Merge "lossless.h: fix function declaration mismatches" into main

Extend VP8EncIterator::i4_boundary_ by 3 bytes to avoid Intra4Preds_NEON
reading deeper into the struct (likely padding) when top is positioned
at offset 29. This data is memset with MSan to prevent a warning due to
its incorrect modeling of tbl instructions.

Prior to:
  169dfbf9 disable Intra4Preds_NEON
there was a mismatch in the preprocessor checks for enabling the
function in NEON and removing the C version; NEON used `BPS == 32` while
the C code was removed unconditionally when building for aarch64. This
patch also normalizes those checks to look for `BPS == 32` and `BPS !=
32` as appropriate.

Bug: b:366668849,webp:372109644
Change-Id: Ic9e6ad4b2d844cb446decd63aec0b2676a89c8d0

.cmake-format.py

@@ -0,0 +1,240 @@
+# ----------------------------------
+# Options affecting listfile parsing
+# ----------------------------------
+with section("parse"):
+
+  # Specify structure for custom cmake functions
+  additional_commands = { 'foo': { 'flags': ['BAR', 'BAZ'],
+             'kwargs': {'DEPENDS': '*', 'HEADERS': '*', 'SOURCES': '*'}}}
+
+  # Override configurations per-command where available
+  override_spec = {}
+
+  # Specify variable tags.
+  vartags = []
+
+  # Specify property tags.
+  proptags = []
+
+# -----------------------------
+# Options affecting formatting.
+# -----------------------------
+with section("format"):
+
+  # Disable formatting entirely, making cmake-format a no-op
+  disable = False
+
+  # How wide to allow formatted cmake files
+  line_width = 80
+
+  # How many spaces to tab for indent
+  tab_size = 2
+
+  # If true, lines are indented using tab characters (utf-8 0x09) instead of
+  # <tab_size> space characters (utf-8 0x20). In cases where the layout would
+  # require a fractional tab character, the behavior of the  fractional
+  # indentation is governed by <fractional_tab_policy>
+  use_tabchars = False
+
+  # If <use_tabchars> is True, then the value of this variable indicates how
+  # fractional indentions are handled during whitespace replacement. If set to
+  # 'use-space', fractional indentation is left as spaces (utf-8 0x20). If set
+  # to `round-up` fractional indentation is replaced with a single tab character
+  # (utf-8 0x09) effectively shifting the column to the next tabstop
+  fractional_tab_policy = 'use-space'
+
+  # If an argument group contains more than this many sub-groups (parg or kwarg
+  # groups) then force it to a vertical layout.
+  max_subgroups_hwrap = 3
+
+  # If a positional argument group contains more than this many arguments, then
+  # force it to a vertical layout.
+  max_pargs_hwrap = 6
+
+  # If a cmdline positional group consumes more than this many lines without
+  # nesting, then invalidate the layout (and nest)
+  max_rows_cmdline = 2
+
+  # If true, separate flow control names from their parentheses with a space
+  separate_ctrl_name_with_space = False
+
+  # If true, separate function names from parentheses with a space
+  separate_fn_name_with_space = False
+
+  # If a statement is wrapped to more than one line, than dangle the closing
+  # parenthesis on its own line.
+  dangle_parens = False
+
+  # If the trailing parenthesis must be 'dangled' on its on line, then align it
+  # to this reference: `prefix`: the start of the statement,  `prefix-indent`:
+  # the start of the statement, plus one indentation  level, `child`: align to
+  # the column of the arguments
+  dangle_align = 'prefix'
+
+  # If the statement spelling length (including space and parenthesis) is
+  # smaller than this amount, then force reject nested layouts.
+  min_prefix_chars = 4
+
+  # If the statement spelling length (including space and parenthesis) is larger
+  # than the tab width by more than this amount, then force reject un-nested
+  # layouts.
+  max_prefix_chars = 10
+
+  # If a candidate layout is wrapped horizontally but it exceeds this many
+  # lines, then reject the layout.
+  max_lines_hwrap = 2
+
+  # What style line endings to use in the output.
+  line_ending = 'unix'
+
+  # Format command names consistently as 'lower' or 'upper' case
+  command_case = 'canonical'
+
+  # Format keywords consistently as 'lower' or 'upper' case
+  keyword_case = 'unchanged'
+
+  # A list of command names which should always be wrapped
+  always_wrap = []
+
+  # If true, the argument lists which are known to be sortable will be sorted
+  # lexicographicall
+  enable_sort = True
+
+  # If true, the parsers may infer whether or not an argument list is sortable
+  # (without annotation).
+  autosort = False
+
+  # By default, if cmake-format cannot successfully fit everything into the
+  # desired linewidth it will apply the last, most agressive attempt that it
+  # made. If this flag is True, however, cmake-format will print error, exit
+  # with non-zero status code, and write-out nothing
+  require_valid_layout = False
+
+  # A dictionary mapping layout nodes to a list of wrap decisions. See the
+  # documentation for more information.
+  layout_passes = {}
+
+# ------------------------------------------------
+# Options affecting comment reflow and formatting.
+# ------------------------------------------------
+with section("markup"):
+
+  # What character to use for bulleted lists
+  bullet_char = '*'
+
+  # What character to use as punctuation after numerals in an enumerated list
+  enum_char = '.'
+
+  # If comment markup is enabled, don't reflow the first comment block in each
+  # listfile. Use this to preserve formatting of your copyright/license
+  # statements.
+  first_comment_is_literal = True
+
+  # If comment markup is enabled, don't reflow any comment block which matches
+  # this (regex) pattern. Default is `None` (disabled).
+  literal_comment_pattern = None
+
+  # Regular expression to match preformat fences in comments default=
+  # ``r'^\s*([`~]{3}[`~]*)(.*)$'``
+  fence_pattern = '^\\s*([`~]{3}[`~]*)(.*)$'
+
+  # Regular expression to match rulers in comments default=
+  # ``r'^\s*[^\w\s]{3}.*[^\w\s]{3}$'``
+  ruler_pattern = '^\\s*[^\\w\\s]{3}.*[^\\w\\s]{3}$'
+
+  # If a comment line matches starts with this pattern then it is explicitly a
+  # trailing comment for the preceeding argument. Default is '#<'
+  explicit_trailing_pattern = '#<'
+
+  # If a comment line starts with at least this many consecutive hash
+  # characters, then don't lstrip() them off. This allows for lazy hash rulers
+  # where the first hash char is not separated by space
+  hashruler_min_length = 10
+
+  # If true, then insert a space between the first hash char and remaining hash
+  # chars in a hash ruler, and normalize its length to fill the column
+  canonicalize_hashrulers = True
+
+  # enable comment markup parsing and reflow
+  enable_markup = True
+
+# ----------------------------
+# Options affecting the linter
+# ----------------------------
+with section("lint"):
+
+  # a list of lint codes to disable
+  disabled_codes = []
+
+  # regular expression pattern describing valid function names
+  function_pattern = '[0-9a-z_]+'
+
+  # regular expression pattern describing valid macro names
+  macro_pattern = '[0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with global
+  # (cache) scope
+  global_var_pattern = '[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with global
+  # scope (but internal semantic)
+  internal_var_pattern = '_[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for variables with local
+  # scope
+  local_var_pattern = '[a-z][a-z0-9_]+'
+
+  # regular expression pattern describing valid names for privatedirectory
+  # variables
+  private_var_pattern = '_[0-9a-z_]+'
+
+  # regular expression pattern describing valid names for public directory
+  # variables
+  public_var_pattern = '[A-Z][0-9A-Z_]+'
+
+  # regular expression pattern describing valid names for function/macro
+  # arguments and loop variables.
+  argument_var_pattern = '[a-z][a-z0-9_]+'
+
+  # regular expression pattern describing valid names for keywords used in
+  # functions or macros
+  keyword_pattern = '[A-Z][0-9A-Z_]+'
+
+  # In the heuristic for C0201, how many conditionals to match within a loop in
+  # before considering the loop a parser.
+  max_conditionals_custom_parser = 2
+
+  # Require at least this many newlines between statements
+  min_statement_spacing = 1
+
+  # Require no more than this many newlines between statements
+  max_statement_spacing = 2
+  max_returns = 6
+  max_branches = 12
+  max_arguments = 5
+  max_localvars = 15
+  max_statements = 50
+
+# -------------------------------
+# Options affecting file encoding
+# -------------------------------
+with section("encode"):
+
+  # If true, emit the unicode byte-order mark (BOM) at the start of the file
+  emit_byteorder_mark = False
+
+  # Specify the encoding of the input file. Defaults to utf-8
+  input_encoding = 'utf-8'
+
+  # Specify the encoding of the output file. Defaults to utf-8. Note that cmake
+  # only claims to support utf-8 so be careful when using anything else
+  output_encoding = 'utf-8'
+
+# -------------------------------------
+# Miscellaneous configurations options.
+# -------------------------------------
+with section("misc"):
+
+  # A dictionary containing any per-command configuration overrides. Currently
+  # only `command_case` is supported.
+  per_command = {}

.gitignore

@@ -3,7 +3,9 @@
 *.pc
 .DS_Store
 .deps
+.idea
 .libs
+.vscode
 /aclocal.m4
 /ar-lib
 /autom4te.cache
@@ -50,5 +52,6 @@ tests/fuzzer/animdecoder_fuzzer
 tests/fuzzer/animencoder_fuzzer
 tests/fuzzer/demux_api_fuzzer
 tests/fuzzer/enc_dec_fuzzer
+tests/fuzzer/huffman_fuzzer
 tests/fuzzer/mux_demux_api_fuzzer
 tests/fuzzer/simple_api_fuzzer

.mailmap

@@ -8,8 +8,12 @@ Vikas Arora <vikasa@google.com>
 <vikasa@google.com> <vikaas.arora@gmail.com>
 <slobodan.prijic@imgtec.com> <Slobodan.Prijic@imgtec.com>
 <vrabaud@google.com> <vincent.rabaud@gmail.com>
+Vincent Rabaud <vrabaud@google.com>
 Tamar Levy <tamar.levy@intel.com>
 <qrczak@google.com> <qrczak>
 Hui Su <huisu@google.com>
 James Zern <jzern@google.com>
 Roberto Alanis <alanisbaez@google.com>
+Brian Ledger <brianpl@google.com>
+Maryla Ustarroz-Calonge <maryla@google.com>
+Yannis Guyon <yguyon@google.com>

.style.yapf

@@ -1,2 +1,2 @@
 [style]
-based_on_style = chromium
+based_on_style = yapf

AUTHORS

@@ -1,19 +1,28 @@
 Contributors:
 - Aidan O'Loan (aidanol at gmail dot com)
 - Alan Browning (browning at google dot com)
+- Alexandru Ardelean (ardeleanalex at gmail dot com)
+- Anuraag Agrawal (anuraaga at gmail dot com)
+- Arthur Eubanks (aeubanks at google dot com)
+- Brian Ledger (brianpl at google dot com)
 - Charles Munger (clm at google dot com)
 - Cheng Yi (cyi at google dot com)
 - Christian Duvivier (cduvivier at google dot com)
 - Christopher Degawa (ccom at randomderp dot com)
 - Clement Courbet (courbet at google dot com)
 - Djordje Pesut (djordje dot pesut at imgtec dot com)
+- Frank Barchard (fbarchard at google dot com)
 - Hui Su (huisu at google dot com)
+- H. Vetinari (h dot vetinari at gmx dot com)
 - Ilya Kurdyukov (jpegqs at gmail dot com)
 - Ingvar Stepanyan (rreverser at google dot com)
 - James Zern (jzern at google dot com)
 - Jan Engelhardt (jengelh at medozas dot de)
 - Jehan (jehan at girinstud dot io)
+- Jeremy Maitin-Shepard (jbms at google dot com)
 - Johann Koenig (johann dot koenig at duck dot com)
+- Jonathan Grant (jgrantinfotech at gmail dot com)
+- Jonliu1993 (13720414433 at 163 dot com)
 - Jovan Zelincevic (jovan dot zelincevic at imgtec dot com)
 - Jyrki Alakuijala (jyrki at google dot com)
 - Konstantin Ivlev (tomskside at gmail dot com)
@@ -22,12 +31,17 @@ Contributors:
 - Mans Rullgard (mans at mansr dot com)
 - Marcin Kowalczyk (qrczak at google dot com)
 - Martin Olsson (mnemo at minimum dot se)
+- Maryla Ustarroz-Calonge (maryla at google dot com)
+- Masahiro Hanada (hanada at atmark-techno dot com)
 - Mikołaj Zalewski (mikolajz at google dot com)
 - Mislav Bradac (mislavm at google dot com)
+- natewood (natewood at fb dot com)
 - Nico Weber (thakis at chromium dot org)
 - Noel Chromium (noel at chromium dot org)
+- Nozomi Isozaki (nontan at pixiv dot co dot jp)
 - Oliver Wolff (oliver dot wolff at qt dot io)
 - Owen Rodley (orodley at google dot com)
+- Ozkan Sezer (sezeroz at gmail dot com)
 - Parag Salasakar (img dot mips1 at gmail dot com)
 - Pascal Massimino (pascal dot massimino at gmail dot com)
 - Paweł Hajdan, Jr (phajdan dot jr at chromium dot org)
@@ -41,6 +55,7 @@ Contributors:
 - Somnath Banerjee (somnath dot banerjee at gmail dot com)
 - Sriraman Tallam (tmsriram at google dot com)
 - Tamar Levy (tamar dot levy at intel dot com)
+- Thiago Perrotta (tperrotta at google dot com)
 - Timothy Gu (timothygu99 at gmail dot com)
 - Urvang Joshi (urvang at google dot com)
 - Vikas Arora (vikasa at google dot com)

Android.mk

@@ -1,3 +1,5 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
 LOCAL_PATH := $(call my-dir)
 
 WEBP_CFLAGS := -Wall -DANDROID -DHAVE_MALLOC_H -DHAVE_PTHREAD -DWEBP_USE_THREAD
@@ -33,6 +35,15 @@ else
   NEON := c
 endif
 
+sharpyuv_srcs := \
+    sharpyuv/sharpyuv.c \
+    sharpyuv/sharpyuv_cpu.c \
+    sharpyuv/sharpyuv_csp.c \
+    sharpyuv/sharpyuv_dsp.c \
+    sharpyuv/sharpyuv_gamma.c \
+    sharpyuv/sharpyuv_neon.$(NEON) \
+    sharpyuv/sharpyuv_sse2.c \
+
 dec_srcs := \
     src/dec/alpha_dec.c \
     src/dec/buffer_dec.c \
@@ -153,6 +164,7 @@ utils_dec_srcs := \
     src/utils/color_cache_utils.c \
     src/utils/filters_utils.c \
     src/utils/huffman_utils.c \
+    src/utils/palette.c \
     src/utils/quant_levels_dec_utils.c \
     src/utils/random_utils.c \
     src/utils/rescaler_utils.c \
@@ -204,12 +216,13 @@ endif  # ENABLE_SHARED=1
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := \
+    $(sharpyuv_srcs) \
     $(dsp_enc_srcs) \
     $(enc_srcs) \
     $(utils_enc_srcs) \
 
 LOCAL_CFLAGS := $(WEBP_CFLAGS)
-LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src
+LOCAL_EXPORT_C_INCLUDES += $(LOCAL_PATH)/src $(LOCAL_PATH)
 
 # prefer arm over thumb mode for performance gains
 LOCAL_ARM_MODE := arm
@@ -279,3 +292,4 @@ include $(WEBP_SRC_PATH)/examples/Android.mk
 ifeq ($(USE_CPUFEATURES),yes)
   $(call import-module,android/cpufeatures)
 endif
+endif  # NDK_ROOT

CMakeLists.txt

@@ -6,7 +6,11 @@
 #  in the file PATENTS.  All contributing project authors may
 #  be found in the AUTHORS file in the root of the source tree.
 
-cmake_minimum_required(VERSION 3.7)
+if(APPLE)
+  cmake_minimum_required(VERSION 3.17)
+else()
+  cmake_minimum_required(VERSION 3.7)
+endif()
 
 if(POLICY CMP0072)
   cmake_policy(SET CMP0072 NEW)
@@ -15,6 +19,14 @@ endif()
 project(WebP C)
 
 # Options for coder / decoder executables.
+if(BUILD_SHARED_LIBS)
+  set(WEBP_LINK_STATIC_DEFAULT OFF)
+else()
+  set(WEBP_LINK_STATIC_DEFAULT ON)
+endif()
+option(WEBP_LINK_STATIC
+       "Link using static libraries. If OFF, use dynamic libraries."
+       ${WEBP_LINK_STATIC_DEFAULT})
 if(NOT EMSCRIPTEN)
   # Disable SIMD on Emscripten by default, as it's a new unstable Wasm feature.
   # Users can still explicitly opt-in to make a SIMD-enabled build.
@@ -33,12 +45,27 @@ option(WEBP_BUILD_LIBWEBPMUX "Build the libwebpmux library." ON)
 option(WEBP_BUILD_WEBPMUX "Build the webpmux command line tool." ON)
 option(WEBP_BUILD_EXTRAS "Build extras." ON)
 option(WEBP_BUILD_WEBP_JS "Emscripten build of webp.js." OFF)
+option(WEBP_BUILD_FUZZTEST "Build the fuzztest tests." OFF)
 option(WEBP_USE_THREAD "Enable threading support" ON)
 option(WEBP_NEAR_LOSSLESS "Enable near-lossless encoding" ON)
 option(WEBP_ENABLE_SWAP_16BIT_CSP "Enable byte swap for 16 bit colorspaces."
        OFF)
 set(WEBP_BITTRACE "0" CACHE STRING "Bit trace mode (0=none, 1=bit, 2=bytes)")
 set_property(CACHE WEBP_BITTRACE PROPERTY STRINGS 0 1 2)
+option(WEBP_ENABLE_WUNUSED_RESULT "Add [[nodiscard]] to some functions. \
+       CMake must be at least 3.21 to force C23" OFF)
+
+if(WEBP_LINK_STATIC)
+  if(WIN32)
+    set(CMAKE_FIND_LIBRARY_SUFFIXES .lib .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  else()
+    set(CMAKE_FIND_LIBRARY_SUFFIXES .a ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  endif()
+  set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+  # vwebp does not compile on Ubuntu with static libraries so disabling it for
+  # now.
+  set(WEBP_BUILD_VWEBP OFF)
+endif()
 
 # Option needed for handling Unicode file names on Windows.
 if(WIN32)
@@ -58,23 +85,42 @@ if(WEBP_BUILD_WEBP_JS)
   set(WEBP_USE_THREAD OFF)
 
   if(WEBP_ENABLE_SIMD)
-    message("wasm2js does not support SIMD, disabling webp.js generation.")
+    message(NOTICE
+            "wasm2js does not support SIMD, disabling webp.js generation.")
   endif()
 endif()
 
+set(SHARPYUV_DEP_LIBRARIES)
+set(SHARPYUV_DEP_INCLUDE_DIRS)
 set(WEBP_DEP_LIBRARIES)
 set(WEBP_DEP_INCLUDE_DIRS)
 
 if(NOT CMAKE_BUILD_TYPE)
   set(CMAKE_BUILD_TYPE "Release"
       CACHE STRING "Build type: Release, Debug, MinSizeRel or RelWithDebInfo"
-      FORCE)
+            FORCE)
 endif()
 
 # Include dependencies.
+if(WEBP_BUILD_ANIM_UTILS
+   OR WEBP_BUILD_CWEBP
+   OR WEBP_BUILD_DWEBP
+   OR WEBP_BUILD_EXTRAS
+   OR WEBP_BUILD_GIF2WEBP
+   OR WEBP_BUILD_IMG2WEBP)
+  set(WEBP_FIND_IMG_LIBS TRUE)
+else()
+  set(WEBP_FIND_IMG_LIBS FALSE)
+endif()
 include(cmake/deps.cmake)
 include(GNUInstallDirs)
 
+if(BUILD_SHARED_LIBS AND NOT DEFINED CMAKE_INSTALL_RPATH)
+  # Set the rpath to match autoconf/libtool behavior. Note this must be set
+  # before target creation.
+  set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+endif()
+
 # ##############################################################################
 # Options.
 if(WEBP_ENABLE_SWAP_16BIT_CSP)
@@ -90,24 +136,63 @@ if(WEBP_UNICODE)
   add_definitions(-DUNICODE -D_UNICODE)
 endif()
 
+if(WIN32 AND BUILD_SHARED_LIBS)
+  add_definitions(-DWEBP_DLL)
+endif()
+
+# pkg-config variables used by *.pc.in.
 set(prefix ${CMAKE_INSTALL_PREFIX})
-set(exec_prefix "\$\{prefix\}")
-set(libdir "\$\{prefix\}/lib")
-set(includedir "\$\{prefix\}/include")
+set(exec_prefix "\${prefix}")
+if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+  set(libdir "${CMAKE_INSTALL_LIBDIR}")
+else()
+  set(libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+endif()
+if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+  set(includedir "${CMAKE_INSTALL_INCLUDEDIR}")
+else()
+  set(includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
+endif()
 set(PTHREAD_LIBS ${CMAKE_THREAD_LIBS_INIT})
 set(INSTALLED_LIBRARIES)
 
+if(MSVC)
+  # match the naming convention used by nmake
+  set(webp_libname_prefix "lib")
+  set(CMAKE_SHARED_LIBRARY_PREFIX "${webp_libname_prefix}")
+  set(CMAKE_IMPORT_LIBRARY_PREFIX "${webp_libname_prefix}")
+  set(CMAKE_STATIC_LIBRARY_PREFIX "${webp_libname_prefix}")
+endif()
+
+if(NOT WIN32)
+  set(CMAKE_C_VISIBILITY_PRESET hidden)
+endif()
+
+if(WEBP_ENABLE_WUNUSED_RESULT)
+  if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.21.0)
+    set(CMAKE_C_STANDARD 23)
+  else()
+    unset(CMAKE_C_STANDARD)
+    add_compile_options($<$<COMPILE_LANGUAGE:C>:-std=gnu2x>)
+  endif()
+  add_compile_options(-Wunused-result)
+  add_definitions(-DWEBP_ENABLE_NODISCARD=1)
+endif()
+
 # ##############################################################################
 # Android only.
 if(ANDROID)
   include_directories(${ANDROID_NDK}/sources/android/cpufeatures)
-  add_library(cpufeatures STATIC
+  add_library(cpufeatures-webp STATIC
               ${ANDROID_NDK}/sources/android/cpufeatures/cpu-features.c)
-  list(APPEND INSTALLED_LIBRARIES cpufeatures)
-  target_link_libraries(cpufeatures dl)
-  set(WEBP_DEP_LIBRARIES ${WEBP_DEP_LIBRARIES} cpufeatures)
-  set(WEBP_DEP_INCLUDE_DIRS ${WEBP_DEP_INCLUDE_DIRS}
-      ${ANDROID_NDK}/sources/android/cpufeatures)
+  list(APPEND INSTALLED_LIBRARIES cpufeatures-webp)
+  target_link_libraries(cpufeatures-webp dl)
+  set(SHARPYUV_DEP_LIBRARIES ${SHARPYUV_DEP_LIBRARIES} cpufeatures-webp)
+  set(WEBP_DEP_LIBRARIES ${WEBP_DEP_LIBRARIES} cpufeatures-webp)
+  set(cpufeatures_include_dir ${ANDROID_NDK}/sources/android/cpufeatures)
+  set(SHARPYUV_DEP_INCLUDE_DIRS ${SHARPYUV_DEP_INCLUDE_DIRS}
+                                ${cpufeatures_include_dir})
+  set(WEBP_DEP_INCLUDE_DIRS ${WEBP_DEP_INCLUDE_DIRS} ${cpufeatures_include_dir})
   add_definitions(-DHAVE_CPU_FEATURES_H=1)
   set(HAVE_CPU_FEATURES_H 1)
 else()
@@ -116,7 +201,7 @@ endif()
 
 function(configure_pkg_config FILE)
   configure_file("${CMAKE_CURRENT_SOURCE_DIR}/${FILE}.in"
-                 "${CMAKE_CURRENT_BINARY_DIR}/${FILE}")
+                 "${CMAKE_CURRENT_BINARY_DIR}/${FILE}" @ONLY)
 
   if(HAVE_MATH_LIBRARY)
     # MSVC doesn't have libm
@@ -125,10 +210,8 @@ function(configure_pkg_config FILE)
     file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/${FILE} ${data})
   endif()
 
-  install(
-    FILES "${CMAKE_CURRENT_BINARY_DIR}/${FILE}"
-    DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig
-  )
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/${FILE}"
+          DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
 endfunction()
 
 # ##############################################################################
@@ -138,23 +221,15 @@ endfunction()
 # E.g.: libimagedec_la_SOURCES  = image_dec.c image_dec.h
 function(parse_Makefile_am FOLDER VAR SRC_REGEX)
   file(READ ${FOLDER}/Makefile.am MAKEFILE_AM)
-  string(REGEX MATCHALL
-               "${SRC_REGEX}_SOURCES[ ]*\\+?=[ ]+[0-9a-z\\._ ]*"
-               FILES_PER_LINE
-               ${MAKEFILE_AM})
+  string(REGEX MATCHALL "${SRC_REGEX}_SOURCES[ ]*\\+?=[ ]+[0-9a-z\\._ ]*"
+               FILES_PER_LINE ${MAKEFILE_AM})
   set(SRCS ${${VAR}})
   foreach(FILES ${FILES_PER_LINE})
     string(FIND ${FILES} "=" OFFSET)
     math(EXPR OFFSET "${OFFSET} + 2")
-    string(SUBSTRING ${FILES}
-                     ${OFFSET}
-                     -1
-                     FILES)
+    string(SUBSTRING ${FILES} ${OFFSET} -1 FILES)
     if(FILES)
-      string(REGEX MATCHALL
-                   "[0-9a-z\\._]+"
-                   FILES
-                   ${FILES})
+      string(REGEX MATCHALL "[0-9a-z\\._]+" FILES ${FILES})
       foreach(FILE ${FILES})
         list(APPEND SRCS ${FOLDER}/${FILE})
       endforeach()
@@ -183,161 +258,17 @@ endforeach()
 
 # Generate the config.h file.
 configure_file(${CMAKE_CURRENT_LIST_DIR}/cmake/config.h.in
-               ${CMAKE_CURRENT_BINARY_DIR}/src/webp/config.h)
+               ${CMAKE_CURRENT_BINARY_DIR}/src/webp/config.h @ONLY)
 add_definitions(-DHAVE_CONFIG_H)
 
-# ##############################################################################
-# Build the webpdecoder library.
-
-# Creates a source file with an unused stub function in $CMAKE_BINARY_DIR and
-# adds it to the specified target. Currently used only with Xcode.
-#
-# See also:
-# https://cmake.org/cmake/help/v3.18/command/add_library.html#object-libraries
-# "Some native build systems (such as Xcode) may not like targets that have
-# only object files, so consider adding at least one real source file to any
-# target that references $<TARGET_OBJECTS:objlib>."
-function(libwebp_add_stub_file TARGET)
-  set(stub_source_dir "${CMAKE_BINARY_DIR}")
-  set(stub_source_file
-      "${stub_source_dir}/libwebp_${TARGET}_stub.c")
-  set(stub_source_code
-      "// Generated file. DO NOT EDIT!\n"
-      "// C source file created for target ${TARGET}.\n"
-      "void libwebp_${TARGET}_stub_function(void)\;\n"
-      "void libwebp_${TARGET}_stub_function(void) {}\n")
-  file(WRITE "${stub_source_file}" ${stub_source_code})
-
-  target_sources(${TARGET} PRIVATE ${stub_source_file})
-endfunction()
-
-if(MSVC)
-  # avoid security warnings for e.g., fopen() used in the examples.
-  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
-else()
-  add_definitions(-Wall)
-endif()
-include_directories(${WEBP_DEP_INCLUDE_DIRS})
-add_library(webpdecode OBJECT ${WEBP_DEC_SRCS})
-target_include_directories(webpdecode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webpdspdecode OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS})
-target_include_directories(webpdspdecode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webputilsdecode
-            OBJECT
-            ${WEBP_UTILS_COMMON_SRCS}
-            ${WEBP_UTILS_DEC_SRCS})
-target_include_directories(webputilsdecode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webpdecoder
-            $<TARGET_OBJECTS:webpdecode>
-            $<TARGET_OBJECTS:webpdspdecode>
-            $<TARGET_OBJECTS:webputilsdecode>)
-if(XCODE)
-  libwebp_add_stub_file(webpdecoder)
-endif()
-target_link_libraries(webpdecoder ${WEBP_DEP_LIBRARIES})
-target_include_directories(
-  webpdecoder
-  PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
-  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
-            $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
-set_target_properties(
-  webpdecoder
-  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
-
-configure_pkg_config("src/libwebpdecoder.pc")
-
-# Build the webp library.
-add_library(webpencode OBJECT ${WEBP_ENC_SRCS})
-target_include_directories(webpencode
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webpdsp
-            OBJECT
-            ${WEBP_DSP_COMMON_SRCS}
-            ${WEBP_DSP_DEC_SRCS}
-            ${WEBP_DSP_ENC_SRCS})
-target_include_directories(webpdsp
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webputils
-            OBJECT
-            ${WEBP_UTILS_COMMON_SRCS}
-            ${WEBP_UTILS_DEC_SRCS}
-            ${WEBP_UTILS_ENC_SRCS})
-target_include_directories(webputils
-                           PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                   ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(webp
-            $<TARGET_OBJECTS:webpdecode>
-            $<TARGET_OBJECTS:webpdsp>
-            $<TARGET_OBJECTS:webpencode>
-            $<TARGET_OBJECTS:webputils>)
-if(XCODE)
-  libwebp_add_stub_file(webp)
-endif()
-target_link_libraries(webp ${WEBP_DEP_LIBRARIES})
-target_include_directories(
-  webp
-  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
-          ${CMAKE_CURRENT_BINARY_DIR}
-  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
-         $<INSTALL_INTERFACE:include>)
-set_target_properties(
-  webp
-  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/encode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
-
-# Make sure the OBJECT libraries are built with position independent code (it is
-# not ON by default).
-set_target_properties(webpdecode
-                      webpdspdecode
-                      webputilsdecode
-                      webpencode
-                      webpdsp
-                      webputils
-                      PROPERTIES POSITION_INDEPENDENT_CODE ON)
-configure_pkg_config("src/libwebp.pc")
-
-# Build the webp demux library.
-add_library(webpdemux ${WEBP_DEMUX_SRCS})
-target_link_libraries(webpdemux webp)
-target_include_directories(webpdemux
-                           PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
-                                   ${CMAKE_CURRENT_BINARY_DIR}
-                           PUBLIC $<INSTALL_INTERFACE:include>)
-set_target_properties(
-  webpdemux
-  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/demux.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
-${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
-
-configure_pkg_config("src/demux/libwebpdemux.pc")
-
 # Set the version numbers.
 macro(set_version FILE TARGET_NAME NAME_IN_MAKEFILE)
-  file(READ ${CMAKE_CURRENT_SOURCE_DIR}/src/${FILE} SOURCE_FILE)
+  file(READ ${CMAKE_CURRENT_SOURCE_DIR}/${FILE} SOURCE_FILE)
   string(REGEX MATCH
-               "${NAME_IN_MAKEFILE}_la_LDFLAGS[^\n]* -version-info [0-9:]+"
-               TMP
+               "${NAME_IN_MAKEFILE}_la_LDFLAGS[^\n]* -version-info [0-9:]+" TMP
                ${SOURCE_FILE})
-  string(REGEX MATCH
-               "[0-9:]+"
-               TMP
-               ${TMP})
-  string(REGEX
-         REPLACE ":"
-                 " "
-                 LT_VERSION
-                 ${TMP})
+  string(REGEX MATCH "[0-9:]+" TMP ${TMP})
+  string(REGEX REPLACE ":" " " LT_VERSION ${TMP})
 
   # See the libtool docs for more information:
   # https://www.gnu.org/software/libtool/manual/libtool.html#Updating-version-info
@@ -356,23 +287,166 @@ macro(set_version FILE TARGET_NAME NAME_IN_MAKEFILE)
 
   set_target_properties(
     ${TARGET_NAME}
-    PROPERTIES VERSION
-               ${LT_CURRENT_MINUS_AGE}.${LT_AGE}.${LT_REVISION}
-               SOVERSION
-               ${LT_CURRENT_MINUS_AGE})
+    PROPERTIES VERSION ${LT_CURRENT_MINUS_AGE}.${LT_AGE}.${LT_REVISION}
+               SOVERSION ${LT_CURRENT_MINUS_AGE})
+  if(APPLE)
+    # For compatibility, set MACHO_COMPATIBILITY_VERSION and
+    # MACHO_CURRENT_VERSION to match libtool. These properties were introduced
+    # in 3.17:
+    # https://cmake.org/cmake/help/latest/prop_tgt/MACHO_COMPATIBILITY_VERSION.html
+    math(EXPR LIBWEBP_MACHO_COMPATIBILITY_VERSION "${LT_CURRENT} + 1")
+    set_target_properties(
+      ${TARGET_NAME}
+      PROPERTIES MACHO_COMPATIBILITY_VERSION
+                 ${LIBWEBP_MACHO_COMPATIBILITY_VERSION}
+                 MACHO_CURRENT_VERSION
+                 ${LIBWEBP_MACHO_COMPATIBILITY_VERSION}.${LT_REVISION})
+  endif()
 endmacro()
-set_version(Makefile.am webp webp)
-set_version(Makefile.am webpdecoder webpdecoder)
-set_version(demux/Makefile.am webpdemux webpdemux)
+
+# ##############################################################################
+# Build the webpdecoder library.
+
+# Creates a source file with an unused stub function in $CMAKE_BINARY_DIR and
+# adds it to the specified target. Currently used only with Xcode.
+#
+# See also:
+# https://cmake.org/cmake/help/v3.18/command/add_library.html#object-libraries
+# "Some native build systems (such as Xcode) may not like targets that have only
+# object files, so consider adding at least one real source file to any target
+# that references $<TARGET_OBJECTS:objlib>."
+function(libwebp_add_stub_file TARGET)
+  set(stub_source_dir "${CMAKE_BINARY_DIR}")
+  set(stub_source_file "${stub_source_dir}/libwebp_${TARGET}_stub.c")
+  set(stub_source_code
+      "// Generated file. DO NOT EDIT!\n"
+      "// C source file created for target ${TARGET}.\n"
+      "void libwebp_${TARGET}_stub_function(void)\;\n"
+      "void libwebp_${TARGET}_stub_function(void) {}\n")
+  file(WRITE "${stub_source_file}" ${stub_source_code})
+
+  target_sources(${TARGET} PRIVATE ${stub_source_file})
+endfunction()
+
+parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv "WEBP_SHARPYUV_SRCS" "")
+add_library(sharpyuv ${WEBP_SHARPYUV_SRCS})
+target_link_libraries(sharpyuv ${SHARPYUV_DEP_LIBRARIES})
+set_version(sharpyuv/Makefile.am sharpyuv sharpyuv)
+target_include_directories(
+  sharpyuv PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                   ${CMAKE_CURRENT_SOURCE_DIR}/src)
+set_target_properties(
+  sharpyuv
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/sharpyuv/sharpyuv_csp.h")
+configure_pkg_config("sharpyuv/libsharpyuv.pc")
+install(
+  TARGETS sharpyuv
+  EXPORT ${PROJECT_NAME}Targets
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp/sharpyuv
+  INCLUDES
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  ${CMAKE_INSTALL_INCLUDEDIR}/webp
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
+if(MSVC)
+  # avoid security warnings for e.g., fopen() used in the examples.
+  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+else()
+  add_compile_options(-Wall)
+endif()
+include_directories(${WEBP_DEP_INCLUDE_DIRS})
+add_library(webpdecode OBJECT ${WEBP_DEC_SRCS})
+target_include_directories(webpdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                              ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webpdspdecode OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS})
+target_include_directories(webpdspdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                 ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputilsdecode OBJECT ${WEBP_UTILS_COMMON_SRCS}
+                                   ${WEBP_UTILS_DEC_SRCS})
+target_include_directories(webputilsdecode PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                   ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(
+  webpdecoder $<TARGET_OBJECTS:webpdecode> $<TARGET_OBJECTS:webpdspdecode>
+              $<TARGET_OBJECTS:webputilsdecode>)
+if(XCODE)
+  libwebp_add_stub_file(webpdecoder)
+endif()
+target_link_libraries(webpdecoder ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webpdecoder
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+  INTERFACE
+    "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR};${CMAKE_CURRENT_BINARY_DIR}>"
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+set_target_properties(
+  webpdecoder
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/libwebpdecoder.pc")
+
+# Build the webp library.
+add_library(webpencode OBJECT ${WEBP_ENC_SRCS})
+target_include_directories(
+  webpencode PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                     ${CMAKE_CURRENT_SOURCE_DIR}/src)
+add_library(webpdsp OBJECT ${WEBP_DSP_COMMON_SRCS} ${WEBP_DSP_DEC_SRCS}
+                           ${WEBP_DSP_ENC_SRCS})
+target_include_directories(webpdsp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                           ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webputils OBJECT ${WEBP_UTILS_COMMON_SRCS} ${WEBP_UTILS_DEC_SRCS}
+                             ${WEBP_UTILS_ENC_SRCS})
+target_include_directories(webputils PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                             ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(webp $<TARGET_OBJECTS:webpdecode> $<TARGET_OBJECTS:webpdsp>
+                 $<TARGET_OBJECTS:webpencode> $<TARGET_OBJECTS:webputils>)
+target_link_libraries(webp sharpyuv)
+if(XCODE)
+  libwebp_add_stub_file(webp)
+endif()
+target_link_libraries(webp ${WEBP_DEP_LIBRARIES})
+target_include_directories(
+  webp PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
+         $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webp
+  PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/encode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+# Make sure the OBJECT libraries are built with position independent code (it is
+# not ON by default).
+set_target_properties(webpdecode webpdspdecode webputilsdecode webpencode
+                      webpdsp webputils PROPERTIES POSITION_INDEPENDENT_CODE ON)
+configure_pkg_config("src/libwebp.pc")
+
+# Build the webp demux library.
+add_library(webpdemux ${WEBP_DEMUX_SRCS})
+target_link_libraries(webpdemux webp)
+target_include_directories(
+  webpdemux PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+  PUBLIC $<INSTALL_INTERFACE:include>)
+set_target_properties(
+  webpdemux
+  PROPERTIES
+    PUBLIC_HEADER
+    "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/demux.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
+${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h")
+
+configure_pkg_config("src/demux/libwebpdemux.pc")
+
+set_version(src/Makefile.am webp webp)
+set_version(src/Makefile.am webpdecoder webpdecoder)
+set_version(src/demux/Makefile.am webpdemux webpdemux)
 file(READ ${CMAKE_CURRENT_SOURCE_DIR}/configure.ac CONFIGURE_FILE)
-string(REGEX MATCH
-             "AC_INIT\\([^\n]*\\[[0-9\\.]+\\]"
-             TMP
-             ${CONFIGURE_FILE})
-string(REGEX MATCH
-             "[0-9\\.]+"
-             PROJECT_VERSION
-             ${TMP})
+string(REGEX MATCH "AC_INIT\\([^\n]*\\[[0-9\\.]+\\]" TMP ${CONFIGURE_FILE})
+string(REGEX MATCH "[0-9\\.]+" PROJECT_VERSION ${TMP})
 
 # Define the libraries to install.
 list(APPEND INSTALLED_LIBRARIES webpdecoder webp webpdemux)
@@ -385,10 +459,8 @@ math(EXPR WEBP_SIMD_FILES_TO_INCLUDE_RANGE
 foreach(I_FILE RANGE ${WEBP_SIMD_FILES_TO_INCLUDE_RANGE})
   list(GET WEBP_SIMD_FILES_TO_INCLUDE ${I_FILE} FILE)
   list(GET WEBP_SIMD_FLAGS_TO_INCLUDE ${I_FILE} SIMD_COMPILE_FLAG)
-  set_source_files_properties(${FILE}
-                              PROPERTIES
-                              COMPILE_FLAGS
-                              ${SIMD_COMPILE_FLAG})
+  set_source_files_properties(${FILE} PROPERTIES COMPILE_FLAGS
+                                                 ${SIMD_COMPILE_FLAG})
 endforeach()
 
 if(NOT WEBP_BUILD_LIBWEBPMUX)
@@ -409,32 +481,32 @@ endif()
 if(WEBP_BUILD_ANIM_UTILS
    OR WEBP_BUILD_CWEBP
    OR WEBP_BUILD_DWEBP
+   OR WEBP_BUILD_EXTRAS
+   OR WEBP_BUILD_FUZZTEST
    OR WEBP_BUILD_GIF2WEBP
    OR WEBP_BUILD_IMG2WEBP
-   OR WEBP_BUILD_VWEBP)
+   OR WEBP_BUILD_VWEBP
+   OR WEBP_BUILD_WEBPMUX
+   OR WEBP_BUILD_WEBPINFO)
   # Example utility library.
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "EXAMPLEUTIL_SRCS"
                     "example_util_[^ ]*")
   list(APPEND EXAMPLEUTIL_SRCS ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h)
   add_library(exampleutil STATIC ${EXAMPLEUTIL_SRCS})
-  target_link_libraries(exampleutil imageioutil)
   target_include_directories(
-    exampleutil
-    PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>)
+    exampleutil PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>)
 
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEIOUTILS_SRCS"
                     "imageio_util_[^ ]*")
   add_library(imageioutil STATIC ${IMAGEIOUTILS_SRCS})
   target_link_libraries(imageioutil webp)
+  target_link_libraries(exampleutil imageioutil)
 
   # Image-decoding utility library.
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/imageio "IMAGEDEC_SRCS"
                     "imagedec_[^ ]*")
   add_library(imagedec STATIC ${IMAGEDEC_SRCS})
-  target_link_libraries(imagedec
-                        imageioutil
-                        webpdemux
-                        webp
+  target_link_libraries(imagedec imageioutil webpdemux webp
                         ${WEBP_DEP_IMG_LIBRARIES})
 
   # Image-encoding utility library.
@@ -443,12 +515,12 @@ if(WEBP_BUILD_ANIM_UTILS
   add_library(imageenc STATIC ${IMAGEENC_SRCS})
   target_link_libraries(imageenc imageioutil webp)
 
-  set_property(TARGET exampleutil
-                      imageioutil
-                      imagedec
-                      imageenc
-               PROPERTY INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/src
-                        ${CMAKE_CURRENT_BINARY_DIR}/src)
+  set_property(
+    TARGET exampleutil imageioutil imagedec imageenc
+    PROPERTY INCLUDE_DIRECTORIES ${CMAKE_CURRENT_SOURCE_DIR}/src
+             ${CMAKE_CURRENT_BINARY_DIR}/src)
+  target_include_directories(imagedec PRIVATE ${WEBP_DEP_IMG_INCLUDE_DIRS})
+  target_include_directories(imageenc PRIVATE ${WEBP_DEP_IMG_INCLUDE_DIRS})
 endif()
 
 if(WEBP_BUILD_DWEBP)
@@ -465,7 +537,8 @@ if(WEBP_BUILD_CWEBP)
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "CWEBP_SRCS" "cwebp")
   add_executable(cwebp ${CWEBP_SRCS})
   target_link_libraries(cwebp exampleutil imagedec webp)
-  target_include_directories(cwebp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  target_include_directories(cwebp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                           ${CMAKE_CURRENT_SOURCE_DIR})
   install(TARGETS cwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 endif()
 
@@ -473,13 +546,12 @@ if(WEBP_BUILD_LIBWEBPMUX)
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/mux "WEBP_MUX_SRCS" "")
   add_library(libwebpmux ${WEBP_MUX_SRCS})
   target_link_libraries(libwebpmux webp)
-  target_include_directories(libwebpmux
-                             PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
-                                     ${CMAKE_CURRENT_SOURCE_DIR})
-  set_version(mux/Makefile.am libwebpmux webpmux)
-  set_target_properties(libwebpmux
-                        PROPERTIES PUBLIC_HEADER
-                                   "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux.h;\
+  target_include_directories(libwebpmux PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+                                                ${CMAKE_CURRENT_SOURCE_DIR})
+  set_version(src/mux/Makefile.am libwebpmux webpmux)
+  set_target_properties(
+    libwebpmux
+    PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux.h;\
 ${CMAKE_CURRENT_SOURCE_DIR}/src/webp/mux_types.h;\
 ${CMAKE_CURRENT_SOURCE_DIR}/src/webp/types.h;")
   set_target_properties(libwebpmux PROPERTIES OUTPUT_NAME webpmux)
@@ -493,11 +565,7 @@ if(WEBP_BUILD_GIF2WEBP)
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "GIF2WEBP_SRCS"
                     "gif2webp")
   add_executable(gif2webp ${GIF2WEBP_SRCS})
-  target_link_libraries(gif2webp
-                        exampleutil
-                        imageioutil
-                        webp
-                        libwebpmux
+  target_link_libraries(gif2webp exampleutil imageioutil webp libwebpmux
                         ${WEBP_DEP_GIF_LIBRARIES})
   target_include_directories(gif2webp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
   install(TARGETS gif2webp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
@@ -509,13 +577,10 @@ if(WEBP_BUILD_IMG2WEBP)
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "IMG2WEBP_SRCS"
                     "img2webp")
   add_executable(img2webp ${IMG2WEBP_SRCS})
-  target_link_libraries(img2webp
-                        exampleutil
-                        imagedec
-                        imageioutil
-                        webp
+  target_link_libraries(img2webp exampleutil imagedec imageioutil webp
                         libwebpmux)
-  target_include_directories(img2webp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  target_include_directories(img2webp PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                              ${CMAKE_CURRENT_SOURCE_DIR})
   install(TARGETS img2webp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 endif()
 
@@ -526,17 +591,17 @@ if(WEBP_BUILD_VWEBP)
     include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
     parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "VWEBP_SRCS" "vwebp")
     add_executable(vwebp ${VWEBP_SRCS})
-    target_link_libraries(vwebp
-                          ${OPENGL_LIBRARIES}
-                          exampleutil
-                          ${GLUT_glut_LIBRARY}
-                          imageioutil
-                          webp
-                          webpdemux)
-    target_include_directories(vwebp
-                               PRIVATE ${GLUT_INCLUDE_DIR}
-                                       ${CMAKE_CURRENT_BINARY_DIR}/src
-                                       ${OPENGL_INCLUDE_DIR})
+    target_link_libraries(
+      vwebp
+      ${OPENGL_LIBRARIES}
+      exampleutil
+      GLUT::GLUT
+      imageioutil
+      webp
+      webpdemux)
+    target_include_directories(
+      vwebp PRIVATE ${GLUT_INCLUDE_DIR} ${CMAKE_CURRENT_BINARY_DIR}/src
+                    ${OPENGL_INCLUDE_DIR})
     install(TARGETS vwebp RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
     if(${CMAKE_SYSTEM_NAME} STREQUAL "Darwin")
       check_c_compiler_flag("-Wno-deprecated-declarations" HAS_NO_DEPRECATED)
@@ -554,7 +619,8 @@ if(WEBP_BUILD_WEBPINFO)
                     "webpinfo")
   add_executable(webpinfo ${WEBPINFO_SRCS})
   target_link_libraries(webpinfo exampleutil imageioutil)
-  target_include_directories(webpinfo PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
+  target_include_directories(webpinfo PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src
+                                              ${CMAKE_CURRENT_SOURCE_DIR}/src)
   install(TARGETS webpinfo RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 endif()
 
@@ -575,61 +641,101 @@ if(WEBP_BUILD_EXTRAS)
   parse_makefile_am(${EXTRAS_MAKEFILE} "WEBP_QUALITY_SRCS" "webp_quality")
   parse_makefile_am(${EXTRAS_MAKEFILE} "VWEBP_SDL_SRCS" "vwebp_sdl")
 
+  # libextras
+  add_library(extras STATIC ${WEBP_EXTRAS_SRCS})
+  target_include_directories(
+    extras PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+                   ${CMAKE_CURRENT_SOURCE_DIR}/src)
+
   # get_disto
   add_executable(get_disto ${GET_DISTO_SRCS})
   target_link_libraries(get_disto imagedec)
-  target_include_directories(get_disto
-                             PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
-                                     ${CMAKE_CURRENT_BINARY_DIR}/src)
+  target_include_directories(get_disto PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+                                               ${CMAKE_CURRENT_BINARY_DIR}/src)
 
   # webp_quality
-  add_executable(webp_quality ${WEBP_QUALITY_SRCS} ${WEBP_EXTRAS_SRCS})
-  target_link_libraries(webp_quality exampleutil imagedec)
-  target_include_directories(webp_quality
-                             PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
-                                     ${CMAKE_CURRENT_BINARY_DIR})
+  add_executable(webp_quality ${WEBP_QUALITY_SRCS})
+  target_link_libraries(webp_quality exampleutil imagedec extras)
+  target_include_directories(webp_quality PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+                                                  ${CMAKE_CURRENT_BINARY_DIR})
 
   # vwebp_sdl
-  find_package(SDL)
-  if(SDL_FOUND)
+  find_package(SDL2 QUIET)
+  if(WEBP_BUILD_VWEBP AND SDL2_FOUND)
     add_executable(vwebp_sdl ${VWEBP_SDL_SRCS})
-    target_link_libraries(vwebp_sdl ${SDL_LIBRARY} imageioutil webp)
-    target_include_directories(vwebp_sdl
-                               PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
-                                       ${CMAKE_CURRENT_BINARY_DIR}
-                                       ${CMAKE_CURRENT_BINARY_DIR}/src
-                                       ${SDL_INCLUDE_DIR})
+    target_link_libraries(vwebp_sdl ${SDL2_LIBRARIES} imageioutil webp)
+    target_include_directories(
+      vwebp_sdl PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+                        ${CMAKE_CURRENT_BINARY_DIR}/src ${SDL2_INCLUDE_DIRS})
     set(WEBP_HAVE_SDL 1)
     target_compile_definitions(vwebp_sdl PUBLIC WEBP_HAVE_SDL)
+
+    set(CMAKE_REQUIRED_INCLUDES "${SDL2_INCLUDE_DIRS}")
+    check_c_source_compiles(
+      "
+        #define SDL_MAIN_HANDLED
+        #include \"SDL.h\"
+        int main(void) {
+          return 0;
+        }
+      "
+      HAVE_JUST_SDL_H)
+    set(CMAKE_REQUIRED_INCLUDES)
+    if(HAVE_JUST_SDL_H)
+      target_compile_definitions(vwebp_sdl PRIVATE WEBP_HAVE_JUST_SDL_H)
+    endif()
   endif()
 endif()
 
 if(WEBP_BUILD_WEBP_JS)
+  # The default stack size changed from 5MB to 64KB in 3.1.27. See
+  # https://crbug.com/webp/614.
+  if(EMSCRIPTEN_VERSION VERSION_GREATER_EQUAL "3.1.27")
+    # TOTAL_STACK size was renamed to STACK_SIZE in 3.1.27. The old name was
+    # kept for compatibility, but prefer the new one in case it is removed in
+    # the future.
+    set(emscripten_stack_size "-sSTACK_SIZE=5MB")
+  else()
+    set(emscripten_stack_size "-sTOTAL_STACK=5MB")
+  endif()
+  find_package(SDL2 REQUIRED)
   # wasm2js does not support SIMD.
   if(NOT WEBP_ENABLE_SIMD)
     # JavaScript version
     add_executable(webp_js ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
-    target_link_libraries(webp_js webpdecoder SDL)
+    target_link_libraries(webp_js webpdecoder SDL2)
     target_include_directories(webp_js PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
     set(WEBP_HAVE_SDL 1)
     set_target_properties(
       webp_js
-      PROPERTIES LINK_FLAGS "-s WASM=0 \
-         -s EXPORTED_FUNCTIONS='[\"_WebpToSDL\"]' -s INVOKE_RUN=0 \
-         -s EXPORTED_RUNTIME_METHODS='[\"cwrap\"]'")
+      PROPERTIES
+        # Emscripten puts -sUSE_SDL2=1 in this variable, though it's needed at
+        # compile time to ensure the headers are downloaded.
+        COMPILE_OPTIONS "${SDL2_LIBRARIES}"
+        LINK_FLAGS
+        "-sWASM=0 ${emscripten_stack_size} \
+         -sEXPORTED_FUNCTIONS=_WebPToSDL -sINVOKE_RUN=0 \
+         -sEXPORTED_RUNTIME_METHODS=cwrap ${SDL2_LIBRARIES} \
+         -sALLOW_MEMORY_GROWTH")
     set_target_properties(webp_js PROPERTIES OUTPUT_NAME webp)
     target_compile_definitions(webp_js PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
   endif()
 
   # WASM version
   add_executable(webp_wasm ${CMAKE_CURRENT_SOURCE_DIR}/extras/webp_to_sdl.c)
-  target_link_libraries(webp_wasm webpdecoder SDL)
+  target_link_libraries(webp_wasm webpdecoder SDL2)
   target_include_directories(webp_wasm PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
   set_target_properties(
     webp_wasm
-    PROPERTIES LINK_FLAGS "-s WASM=1 \
-       -s EXPORTED_FUNCTIONS='[\"_WebpToSDL\"]' -s INVOKE_RUN=0 \
-       -s EXPORTED_RUNTIME_METHODS='[\"cwrap\"]'")
+    PROPERTIES
+      # Emscripten puts -sUSE_SDL2=1 in this variable, though it's needed at
+      # compile time to ensure the headers are downloaded.
+      COMPILE_OPTIONS "${SDL2_LIBRARIES}"
+      LINK_FLAGS
+      "-sWASM=1 ${emscripten_stack_size} \
+       -sEXPORTED_FUNCTIONS=_WebPToSDL -sINVOKE_RUN=0 \
+       -sEXPORTED_RUNTIME_METHODS=cwrap ${SDL2_LIBRARIES} \
+       -sALLOW_MEMORY_GROWTH")
   target_compile_definitions(webp_wasm PUBLIC EMSCRIPTEN WEBP_HAVE_SDL)
 
   target_compile_definitions(webpdspdecode PUBLIC EMSCRIPTEN)
@@ -641,14 +747,15 @@ if(WEBP_BUILD_ANIM_UTILS)
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "ANIM_DIFF_SRCS"
                     "anim_diff")
   add_executable(anim_diff ${ANIM_DIFF_SRCS})
-  target_link_libraries(anim_diff
-                        exampleutil
-                        imagedec
-                        imageenc
-                        imageioutil
-                        webp
-                        webpdemux
-                        ${WEBP_DEP_GIF_LIBRARIES})
+  target_link_libraries(
+    anim_diff
+    exampleutil
+    imagedec
+    imageenc
+    imageioutil
+    webp
+    webpdemux
+    ${WEBP_DEP_GIF_LIBRARIES})
   target_include_directories(anim_diff PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
 
   # anim_dump
@@ -656,45 +763,63 @@ if(WEBP_BUILD_ANIM_UTILS)
   parse_makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/examples "ANIM_DUMP_SRCS"
                     "anim_dump")
   add_executable(anim_dump ${ANIM_DUMP_SRCS})
-  target_link_libraries(anim_dump
-                        exampleutil
-                        imagedec
-                        imageenc
-                        imageioutil
-                        webp
-                        webpdemux
-                        ${WEBP_DEP_GIF_LIBRARIES})
+  target_link_libraries(
+    anim_dump
+    exampleutil
+    imagedec
+    imageenc
+    imageioutil
+    webp
+    webpdemux
+    ${WEBP_DEP_GIF_LIBRARIES})
   target_include_directories(anim_dump PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
 endif()
 
+if(WEBP_BUILD_FUZZTEST)
+  add_subdirectory(tests/fuzzer)
+endif()
+
 # Install the different headers and libraries.
-install(TARGETS ${INSTALLED_LIBRARIES}
-        EXPORT ${PROJECT_NAME}Targets
-        PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp
-        INCLUDES
-        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+install(
+  TARGETS ${INSTALLED_LIBRARIES}
+  EXPORT ${PROJECT_NAME}Targets
+  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/webp
+  INCLUDES
+  DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 set(ConfigPackageLocation ${CMAKE_INSTALL_DATADIR}/${PROJECT_NAME}/cmake/)
-install(EXPORT ${PROJECT_NAME}Targets
-        NAMESPACE ${PROJECT_NAME}::
+install(EXPORT ${PROJECT_NAME}Targets NAMESPACE ${PROJECT_NAME}::
         DESTINATION ${ConfigPackageLocation})
 
 # Create the CMake version file.
 include(CMakePackageConfigHelpers)
 write_basic_package_version_file(
   "${CMAKE_CURRENT_BINARY_DIR}/WebPConfigVersion.cmake"
-  VERSION ${PACKAGE_VERSION}
-  COMPATIBILITY AnyNewerVersion)
+  VERSION ${PACKAGE_VERSION} COMPATIBILITY AnyNewerVersion)
 
 # Create the Config file.
 include(CMakePackageConfigHelpers)
+# Fix libwebpmux reference. The target name libwebpmux is used for compatibility
+# purposes, but the library mentioned in WebPConfig.cmake should be the
+# unprefixed version. Note string(...) can be replaced with list(TRANSFORM ...)
+# if cmake_minimum_required is >= 3.12.
+string(REGEX REPLACE "libwebpmux" "webpmux" INSTALLED_LIBRARIES
+                     "${INSTALLED_LIBRARIES}")
+
+if(MSVC)
+  # For compatibility with nmake, MSVC builds use a custom prefix (lib) that
+  # needs to be included in the library name.
+  string(REGEX REPLACE "[A-Za-z0-9_]+" "${CMAKE_STATIC_LIBRARY_PREFIX}\\0"
+                       INSTALLED_LIBRARIES "${INSTALLED_LIBRARIES}")
+endif()
+
 configure_package_config_file(
   ${CMAKE_CURRENT_SOURCE_DIR}/cmake/WebPConfig.cmake.in
   ${CMAKE_CURRENT_BINARY_DIR}/WebPConfig.cmake
-  INSTALL_DESTINATION
-  ${ConfigPackageLocation})
+  INSTALL_DESTINATION ${ConfigPackageLocation}
+  PATH_VARS CMAKE_INSTALL_INCLUDEDIR)
 
 # Install the generated CMake files.
 install(FILES "${CMAKE_CURRENT_BINARY_DIR}/WebPConfigVersion.cmake"
@@ -726,7 +851,6 @@ foreach(I_MAN RANGE ${MAN_PAGES_RANGE})
   if(WEBP_BUILD_${EXEC_BUILD})
     list(GET MAN_PAGES ${I_MAN} MAN_PAGE)
     install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/man/${MAN_PAGE}
-            DESTINATION ${CMAKE_INSTALL_MANDIR}/man1
-            COMPONENT doc)
+            DESTINATION ${CMAKE_INSTALL_MANDIR}/man1 COMPONENT doc)
   endif()
 endforeach()

CONTRIBUTING.md

@@ -19,10 +19,59 @@ again.
 
 All submissions, including submissions by project members, require review. We
 use a [Gerrit](https://www.gerritcodereview.com) instance hosted at
-https://chromium-review.googlesource.com for this purpose. See the
+https://chromium-review.googlesource.com for this purpose.
+
+## Sending patches
+
+The basic git workflow for modifying libwebp code and sending for review is:
+
+1.  Get the latest version of the repository locally:
+
+    ```sh
+    git clone https://chromium.googlesource.com/webm/libwebp && cd libwebp
+    ```
+
+2.  Copy the commit-msg script into ./git/hooks (this will add an ID to all of
+    your commits):
+
+    ```sh
+    curl -Lo .git/hooks/commit-msg https://chromium-review.googlesource.com/tools/hooks/commit-msg && chmod u+x .git/hooks/commit-msg
+    ```
+
+3.  Modify the local copy of libwebp. Make sure the code
+    [builds successfully](https://chromium.googlesource.com/webm/libwebp/+/HEAD/doc/building.md#cmake).
+
+4.  Choose a short and representative commit message:
+
+    ```sh
+    git commit -a -m "Set commit message here"
+    ```
+
+5.  Send the patch for review:
+
+    ```sh
+    git push https://chromium-review.googlesource.com/webm/libwebp HEAD:refs/for/main
+    ```
+
+    Go to https://chromium-review.googlesource.com to view your patch and
+    request a review from the maintainers.
+
+See the
 [WebM Project page](https://www.webmproject.org/code/contribute/submitting-patches/)
 for additional details.
 
+## Code Style
+
+The C code style is based on the
+[Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html) and
+`clang-format --style=Google`, though this project doesn't use the tool to
+enforce the formatting.
+
+CMake files are formatted with
+[cmake-format](https://cmake-format.readthedocs.io/en/latest/). `cmake-format
+-i` can be used to format individual files, it will use the settings from
+`.cmake-format.py`.
+
 ## Community Guidelines
 
 This project follows

ChangeLog

@@ -1,12 +1,506 @@
+8a6a55bb update NEWS
+cf7c5a5d provide a way to opt-out/override WEBP_NODISCARD
+cc34288a update ChangeLog (tag: v1.4.0-rc1)
+f13c0886 NEWS: fix date
+74555950 Merge "vwebp: fix window title when options are given" into 1.4.0
+d781646c vwebp: fix window title when options are given
+c2e394de update NEWS
+f6d15cb7 bump version to 1.4.0
+57c388b8 update AUTHORS
+b3d1b2cb Merge changes I26f4aa22,I83386b6c,I320ed1a2 into main
+07216886 webp-container-spec: fix VP8 chunk ref ('VP8'->'VP8 ')
+f88666eb webp_js/*.html: fix canvas mapping
+e2c8f233 cmake,wasm: simplify SDL2 related flags
+d537cd37 cmake: fix vwebp_sdl compile w/libsdl-org release
+6c484cbf CMakeLists.txt: add missing WEBP_BUILD_EXTRAS check
+7b0bc235 man/cwebp.1: add more detail to -partition_limit
+3c0011bb WebPMuxGetChunk: add an assert
+955a3d14 Merge "muxread,MuxGet: add an assert" into main
+00abc000 muxread,MuxGet: add an assert
+40e85a0b Have the window title reflect the filename.
+1bf46358 man/cwebp.1: clarify -pass > 1 behavior w/o -size/-psnr
+eba03acb webp-container-spec: replace 'above' with 'earlier'
+a16d30cb webp-container-spec: clarify chunk order requirements
+8a7e9112 Merge "CMakeLists.txt: apply cmake-format" into main
+7fac6c1b Merge "Copy C code to not have multiplication overflow" into main
+e2922e43 Merge "Check for the presence of the ANDROID_ABI variable" into main
+501d9274 Copy C code to not have multiplication overflow
+fba7d62e CMakeLists.txt: apply cmake-format
+661c1b66 Merge "windows exports: use dllexport attribute, instead of visibility." into main
+8487860a windows exports: use dllexport attribute, instead of visibility.
+8ea678b9 webp/mux.h: data lifetime note w/copy_data=0
+79e05c7f Check for the presence of the ANDROID_ABI variable
+45f995a3 Expose functions for managing non-image chunks on WebPAnimEncoder
+1fb9f3dc gifdec: fix ErrorGIFNotAvailable() declaration
+4723db65 cosmetics: s/SANITY_CHECK/DCHECK/
+f4b9bc9e clear -Wextra-semi-stmt warnings
+713982b8 Limit animdecoder_fuzzer to 320MB
+cbe825e4 cmake: fix sharpyuv simd files' build
+f99305e9 Makefile.vc: add ARM64 support
+5efd6300 mv SharpYuvEstimate420Risk to extras/
+e78e924f Makefile.vc: add sharpyuv_risk_table.obj
+d7a0506d Add YUV420 riskiness metric.
+89c5b917 Merge "BuildHuffmanTable check sorted[] array bounds before writing" into main
+34c80749 Remove alpha encoding pessimization.
+13d9c30b Add a WEBP_NODISCARD
+24d7f9cb Switch code to SDL2.
+0b56dedc BuildHuffmanTable check sorted[] array bounds before writing
+a429c0de sharpyuv: convert some for() to do/while
+f0cd7861 DoSharpArgbToYuv: remove constant from loop
+339231cc SharpYuvConvertWithOptions,cosmetics: fix formatting
+307071f1 Remove medium/large code model-specific inline asm
+deadc339 Fix transfer functions where toGamma and toLinear are swapped.
+e7b78d43 Merge "Fix bug in FromLinearLog100." into main
+15a1309e Merge "webp-lossless-bitstream-spec: delete extra blank line" into main
+54ca9752 Fix bug in FromLinearLog100.
+d2cb2d8c Dereference after NULL check.
+e9d50107 webp-lossless-bitstream-spec: delete extra blank line
+78657971 Merge changes Ief442c90,Ie6e9c9a5 into main
+e30a5884 webp-lossless-bitstream-spec: update variable names
+09ca1368 Merge "webp-container-spec: change assert to MUST be TRUE" into main
+38cb4fc0 iosbuild,xcframeworkbuild: add SharpYuv framework
+40afa926 webp-lossless-bitstream-spec: simplify abstract
+9db21143 webp-container-spec: change assert to MUST be TRUE
+cdbf88ae Fix typo in API docs for incremental decoding
+05c46984 Reformat vcpkg build instructions.
+8534f539 Merge "Never send VP8_STATUS_SUSPENDED back in non-incremental." into main
+35e197bd Never send VP8_STATUS_SUSPENDED back in non-incremental.
+61441425 Add vcpkg installation instructions
+dce8397f Fix next is invalid pointer when WebPSafeMalloc fails
+57c58105 Cmake: wrong public macro WEBP_INCLUDE_DIRS
+c1ffd9ac Merge "vp8l_enc: fix non-C90 code" into main
+a3965948 Merge changes If628bb93,Ic79f6309,I45f0db23 into main
+f80e9b7e vp8l_enc: fix non-C90 code
+accd141d Update lossless spec for two simple codes.
+ac17ffff Fix non-C90 code.
+433c7dca Fix static analyzer warnings.
+5fac76cf Merge tag 'v1.3.2'
+ca332209 update ChangeLog (tag: v1.3.2)
+1ace578c update NEWS
+63234c42 bump version to 1.3.2
+a35ea50d Add a fuzzer for ReadHuffmanCodes
+95ea5226 Fix invalid incremental decoding check.
+2af26267 Fix OOB write in BuildHuffmanTable.
+902bc919 Fix OOB write in BuildHuffmanTable.
+7ba44f80 Homogenize "__asm__ volatile" vs "asm volatile"
+68e27135 webp-container-spec: reorder example chunk layout
+943b932a Merge changes I6a4d0a04,Ibc37b91e into main
+1cc94f95 decode.h: wrap idec example in /* */
+63acdd1e decode.h: fix decode example
+aac5c5d0 ReadHuffmanCode: rm redundant num code lengths check
+a2de25f6 webp-lossless-bitstream-spec: normalize list item case
+68820f0e webp-lossless-bitstream-spec: normalize pixel ref
+cdb31aa8 webp-lossless-bitstream-spec: add missing periods
+0535a8cf webp-lossless-bitstream-spec: fix grammar
+b6c4ce26 normalize numbered list item format
+dd7364c3 Merge "palette.c: fix msvc warnings" into main
+c63c5df6 palette.c: fix msvc warnings
+0a2cad51 webp-container-spec: move terms from intro section
+dd88d2ff webp-lossless-bitstream-spec: color_cache -> color cache
+6e750547 Merge changes I644d7d39,Icf05491e,Ic02e6652,I63b11258 into main
+67a7cc2b webp-lossless-bitstream-spec: fix code blocks
+1432ebba Refactor palette sorting computation.
+cd436142 webp-lossless-bitstream-spec: block -> chunk
+3cb66f64 webp-lossless-bitstream-spec: add some missing commas
+56471a53 webp-lossless-bitstream-spec: normalize item text in 5.1
+af7fbfd2 vp8l_dec,ReadTransform: improve error status reporting
+7d8e0896 vp8l_dec: add VP8LSetError()
+a71ce1cf animencoder_fuzzer: fix error check w/Nallocfuzz
+e94b36d6 webp-lossless-bitstream-spec: relocate details from 5.1
+84628e56 webp-lossless-bitstream-spec: clarify image width changes
+ee722997 alpha_dec: add missing VP8SetError()
+0081693d enc_dec_fuzzer: use WebPDecode()
+0fcb311c enc_dec_fuzzer: fix WebPEncode/pic.error_code check
+982c177c webp-lossless-bitstream-spec: fix struct member refs
+56cf5625 webp-lossless-bitstream-spec: use RFC 7405 for ABNF
+6c6b3fd3 webp-lossless-bitstream-spec,cosmetics: delete blank lines
+29b9eb15 Merge changes Id56ca4fd,I662bd1d7 into main
+47c0af8d ReadHuffmanCodes: rm max_alphabet_size calc
+b92deba3 animencoder_fuzzer: no WebPAnimEncoderAssemble check w/nallocfuzz
+6be9bf8b animencoder_fuzzer: fix leak on alloc failure
+5c965e55 vp8l_dec,cosmetics: add some /*param=*/ comments
+e4fc2f78 webp-lossless-bitstream-spec: add validity note for max_symbol
+71916726 webp-lossless-bitstream-spec: fix max_symbol definition
+eac3bd5c Have the palette code be in its own file.
+e2c85878 Add an initializer for the SharpYuvOptions struct.
+4222b006 Merge tag 'v1.3.1'
+25d94f47 Implement more transfer functions in libsharpyuv
+2153a679 Merge changes Id0300937,I5dba5ccf,I57bb68e0,I2dba7b4e,I172aca36, ... into main
+4298e976 webp-lossless-bitstream-spec: add PredictorTransformOutput
+cd7e02be webp-lossless-bitstream-spec: fix RIFF-header ABNF
+6c3845f9 webp-lossless-bitstream-spec: split LZ77 Backward Ref section
+7f1b6799 webp-lossless-bitstream-spec: split Meta Prefix Codes section
+7b634d8f webp-lossless-bitstream-spec: note transform order
+6d6d4915 webp-lossless-bitstream-spec: update transformations text
+fd7bb21c update ChangeLog (tag: v1.3.1-rc2, tag: v1.3.1)
+e1adea50 update NEWS
+6b1c722a lossless_common.h,cosmetics: fix a typo
+08d60d60 webp-lossless-bitstream-spec: split code length section
+7a12afcc webp-lossless-bitstream-spec: rm unused anchor
+43393320 enc/*: normalize WebPEncodingSetError() calls
+287fdefe enc/*: add missing WebPEncodingSetError() calls
+c3bd7cff EncodeAlphaInternal: add missing error check
+14a9dbfb webp-lossless-bitstream-spec: refine single node text
+64819c7c Implement ExtractGreen_SSE2
+d49cfbb3 vp8l_enc,WriteImage: add missing error check
+2e5a9ec3 muxread,MuxImageParse: add missing error checks
+ebb6f949 cmake,emscripten: explicitly set stack size
+59a2b1f9 WebPDecodeYUV: check u/v/stride/uv_stride ptrs
+8e965ccb Call png_get_channels() to see if image has alpha
+fe80fbbd webp-container-spec: add some missing commas
+e8ed3176 Merge "treat FILTER_NONE as a regular Unfilter[] call" into main
+03a7a048 webp-lossless-bitstream-spec: rm redundant statement
+c437c7aa webp-lossless-bitstream-spec: mv up prefix code group def
+e4f17a31 webp-lossless-bitstream-spec: fix section reference
+e2ecd5e9 webp-lossless-bitstream-spec: clarify ABNF syntax
+8b55425a webp-lossless-bitstream-spec: refine pixel copy text
+29c9f2d4 webp-lossless-bitstream-spec: minor wording updates
+6b02f660 treat FILTER_NONE as a regular Unfilter[] call
+7f75c91c webp-container-spec: fix location of informative msg
+f6499943 webp-container-spec: consistently quote FourCCs
+49918af3 webp-container-spec: minor wording updates
+7f0a3419 update ChangeLog (tag: v1.3.1-rc1)
+bab7efbe update NEWS
+7138bf8f bump version to 1.3.1
+435b4ded update AUTHORS
+47351229 update .mailmap
+46bc4fc9 Merge "Switch ExtraCost to ints and implement it in SSE." into main
+828b4ce0 Switch ExtraCost to ints and implement it in SSE.
+ff6c7f4e CONTRIBUTING.md: add C style / cmake-format notes
+dd530437 add .cmake-format.py
+adbe2cb1 cmake,cosmetics: apply cmake-format
+15b36508 doc/webp-container-spec: rm future codec comment
+c369c4bf doc/webp-lossless-bitstream-spec: improve link text
+1de35f47 doc/webp-container-spec: don't use 'currently'
+bb06a16e doc/webp-container-spec: prefer present tense
+9f38b71e doc/webp-lossless-bitstream-spec: prefer present tense
+7acb6b82 doc/webp-container-spec: avoid i.e. & e.g.
+4967e7cd doc/webp-lossless-bitstream-spec: avoid i.e. & e.g.
+e3366659 Merge "Do not find_package image libraries if not needed." into main
+428588ef clarify single leaf node trees and use of canonical prefix coding
+709ec152 Do not find_package image libraries if not needed.
+8dd80ef8 fuzz_utils.h: lower kFuzzPxLimit w/ASan
+8f187b9f Clean message calls in CMake
+cba30078 WebPConfig.cmake.in: use calculated include path
+6cf9a76a Merge "webp-lossless-bitstream-spec: remove use of 'dynamics'" into main
+740943b2 Merge "Specialize and optimize ITransform_SSE2 using do_two" into main
+2d547e24 Compare kFuzzPxLimit to max_num_operations
+ac42dde1 Specialize and optimize ITransform_SSE2 using do_two
+17e0ef1d webp-lossless-bitstream-spec: remove use of 'dynamics'
+ed274371 neon.h,cosmetics: clear a couple lint warnings
+3fb82947 cpu.h,cosmetics: segment defines
+0c496a4f cpu.h: add WEBP_AARCH64
+8151f388 move VP8GetCPUInfo declaration to cpu.c
+916548c2 Make kFuzzPxLimit sanitizer dependent
+4070b271 advanced_api_fuzzer: reduce scaling limit
+761f49c3 Merge "webp-lossless-bitstream-spec: add missing bits to ABNF" into main
+84d04c48 webp-lossless-bitstream-spec: add missing bits to ABNF
+0696e1a7 advanced_api_fuzzer: reduce scaling limit
+93d88aa2 Merge "deps.cmake: remove unneeded header checks" into main
+118e0035 deps.cmake: remove unneeded header checks
+4c3d7018 webp-lossless-bitstream-spec: condense normal-prefix-code
+a6a09b32 webp-lossless-bitstream-spec: fix 2 code typos
+50ac4f7c Merge "cpu.h: enable NEON w/_M_ARM64EC" into main
+4b7d7b4f Add contribution instructions
+0afbd97b cpu.h: enable NEON w/_M_ARM64EC
+349f4353 Merge changes Ibd89e56b,Ic57e7f84,I89096614 into main
+8f7513b7 upsampling_neon.c: fix WEBP_SWAP_16BIT_CSP check
+cbf624b5 advanced_api_fuzzer: reduce scaling limit
+89edfdd1 Skip slow scaling in libwebp advanced_api_fuzzer
+859f19f7 Reduce libwebp advanced_api_fuzzer threshold
+a4f04835 Merge changes Ic389aaa2,I329ccd79 into main
+1275fac8 Makefile.vc: fix img2webp link w/dynamic cfg
+2fe27bb9 img2webp: normalize help output
+24bed3d9 cwebp: reflow -near_lossless help text
+0825faa4 img2webp: add -sharp_yuv/-near_lossless
+d64e6d7d Merge "PaletteSortModifiedZeng: fix leak on error" into main
+0e12a22d Merge "EncodeAlphaInternal: clear result->bw on error" into main
+0edbb6ea PaletteSortModifiedZeng: fix leak on error
+41ffe04e Merge "Update yapf style from "chromium" to "yapf"" into main
+2d9d9265 Update yapf style from "chromium" to "yapf"
+a486d800 EncodeAlphaInternal: clear result->bw on error
+1347a32d Skip big scaled advanced_api_fuzzer
+52b6f067 Fix scaling limit in advanced_api_fuzzer.c
+73618428 Limit scaling in libwebp advanced_api_fuzzer.c
+b54d21a0 Merge "CMakeLists.txt: allow CMAKE_INSTALL_RPATH to be set empty" into main
+31c28db5 libwebp{,demux,mux}.pc.in: Requires -> Requires.private
+d9a505ff CMakeLists.txt: allow CMAKE_INSTALL_RPATH to be set empty
+bdf33d03 Merge tag 'v1.3.0'
+b5577769 update ChangeLog (tag: v1.3.0-rc1, tag: v1.3.0)
+0ba77244 update NEWS
+e763eb1e bump version to 1.3.0
+2a8686fc update AUTHORS
+106a57c1 Merge "*/Android.mk: add a check for NDK_ROOT" into main
+c5e841c4 Merge "extras: WebpToSDL -> WebPToSDL" into main
+dbc30715 Merge "xcframeworkbuild.sh: bump MACOSX_CATALYST_MIN_VERSION" into main
+6fc1a9f9 */Android.mk: add a check for NDK_ROOT
+d3e151fc doc/api.md,webp_js/README.md: Webp -> WebP
+ed92a626 extras: WebpToSDL -> WebPToSDL
+6eb0189b xcframeworkbuild.sh: bump MACOSX_CATALYST_MIN_VERSION
+1d58575b CMake: align .pc variables with autoconf
+e5fe2cfc webp-lossless-bitstream-spec,cosmetics: reflow paragraphs
+0ceeeab9 webp-lossless-bitstream-spec: add amendment note
+607611cd Merge "webp-container-spec: normalize section title case" into main
+f853685e lossless: SUBTRACT_GREEN -> SUBTRACT_GREEN_TRANSFORM
+786497e4 webp-lossless-bitstream-spec: fix inv color txfm description
+c6ac672d webp-lossless-bitstream-spec: fix num_code_lengths check
+b5700efb webp-lossless-bitstream-spec,cosmetics: grammar/capitalization
+d8ed8c11 webp-container-spec: normalize section title case
+52ec0b8f Merge changes Ie975dbb5,Ifc8c93af,I6ca7c5d6,I2e8d66f5,I152477b8 into main
+5097ef62 webp-container-spec,cosmetics: grammar/capitalization
+e3ba2b1f webp-lossless-bitstream-spec,cosmetics: reflow abstract
+1e8e3ded webp-lossless-bitstream-spec: reword abstract re alpha
+017cb6fa webp-container-spec,cosmetics: normalize range syntax
+f6a4684b webp-lossless-bitstream-spec,cosmetics: normalize range syntax
+54ebd5a3 webp-lossless-bitstream-spec: limit dist map lut to 69 cols
+44741f9c webp-lossless-bitstream-spec: fix dist mapping example
+fad0ece7 pnmdec.c: use snprintf instead of sprintf
+3f73e8f7 sharpyuv: add SharpYuvGetVersion()
+ce2f2d66 SharpYuvConvert: fix a race on SharpYuvGetCPUInfo
+a458e308 sharpyuv_dsp.h: restore sharpyuv_cpu.h include
+9ba800a7 Merge changes Id72fbf3b,Ic59d23a2 into main
+979c0ebb sharpyuv: add SharpYuvGetCPUInfo
+8bab09a4 Merge "*.pc.in: rename lib_prefix to webp_libname_prefix" into main
+769387c5 cpu.c,cosmetics: fix a typo
+a02978c2 sharpyuv/Makefile.am+cmake: add missing -lm
+28aedcb9 *.pc.in: rename lib_prefix to webp_libname_prefix
+c42e6d5a configure.ac: export an empty lib_prefix variable
+dfc843aa Merge "*.pc.in: add lib prefix to lib names w/MSVC" into main
+2498209b *.pc.in: add lib prefix to lib names w/MSVC
+ac252b61 Merge "analysis_enc.c: fix a dead store warning" into main
+56944762 analysis_enc.c: fix a dead store warning
+d34f9b99 Merge "webp-lossless-bitstream-spec: convert BNF to ABNF" into main
+dc05b4db Merge changes I96bc063c,I45880467,If9e18e5a,I6ee938e4,I0a410b28, ... into main
+83270c7f webp-container-spec: add prose for rendering process
+73b19b64 webp-container-spec: note reserved fields MUST be ignored
+57101d3f webp-lossless-bitstream-spec: improve 'small' color table stmt
+dfd32e45 webp-container-spec: remove redundant sentence
+8a6185dd doc/webp-*: fix some punctuation, grammar
+72776530 webp-lossless-bitstream-spec: convert BNF to ABNF
+d992bb08 cmake: rename cpufeatures target to cpufeatures-webp
+3ed2b275 webp-container-spec: clarify background color note
+951c292d webp-container-spec: come too late -> out of order
+902dd787 webp-container-spec: prefer hex literals
+a8f6b5ee webp-container-spec: change SHOULD to MUST w/ANIM chunk
+1dc59435 webp-container-spec: add unknown fields MUST be ignored
+280a810f webp-container-spec: make padding byte=0 a MUST
+41f0bf68 webp-container-spec: update note on trailing data
+6bdd36db webp-container-spec: clarify Chunk Size is in bytes
+87e36c48 Merge "webp_js/README.md,cosmetics: reflow some lines" into main
+5b01f321 Merge "Update Windows makefile to build libsharpyuv library." into main
+19b1a71c webp_js/README.md,cosmetics: reflow some lines
+780db756 Update Windows makefile to build libsharpyuv library.
+e407d4b3 CMakeLists.txt: replace GLUT_glut_LIBRARY w/GLUT::GLUT
+abf73d62 Merge "WebPConfig.cmake.in: add find_dependency(Threads)" into main
+25807fb4 Merge "cmake: restore compatibility with cmake < 3.12" into main
+5dbc4bfa WebPConfig.cmake.in: add find_dependency(Threads)
+b2a175dd Merge "Update wasm instructions." into main
+cb90f76b Update wasm instructions.
+02d15258 cmake: restore compatibility with cmake < 3.12
+5ba046e2 CMake: add_definitions -> add_compile_options
+e68765af dsp,neon: use vaddv in a few more places
+e8f83de2 Set libsharpyuv include dir to 'webp' subdirectory.
+15a91ab1 cmake,cosmetics: apply cmake-format
+0dd49d1a CMakeLists.txt: set @ONLY in configure_file() calls
+62b1bfe8 Merge changes I2877e7bb,I777cad70,I15af7d1a,I686e6740,If10538a9, ... into main
+95c8fe5f Merge changes Iecea3603,I9dc228ab into main
+e7c805cf picture_csp_enc.c: remove SafeInitSharpYuv
+6af8845a sharpyuv: prefer webp/types.h
+639619ce cmake: fix dll exports
+782ed48c sharpyuv,SharpYuvInit: add mutex protection when available
+cad0d5ad sharyuv_{neon,sse2}.c: merge WEBP_USE_* sections
+ef70ee06 add a few missing <stddef.h> includes for NULL
+f0f9eda4 sharpyuv.h: remove <inttypes.h>
+9b902cba Merge "picture_csp_enc.c,CheckNonOpaque: rm unneeded local" into main
+9c1d457c cmake/cpu.cmake: remove unused variable
+9ac25bcb CMakeLists.txt,win32: match naming convention used by nmake
+76c353ba picture_csp_enc.c,CheckNonOpaque: rm unneeded local
+5000de54 Merge "cwebp: fix WebPPictureHasTransparency call" into main
+e1729309 Merge "WebPPictureHasTransparency: add missing pointer check" into main
+00ff988a vp8l_enc,AddSingleSubGreen: clear int sanitizer warnings
+e2fecc22 dsp/lossless_enc.c: clear int sanitizer warnings
+129cf9e9 dsp/lossless.c: clear int sanitizer warnings
+ad7d1753 dsp/lossless_enc.c: clear int sanitizer warnings
+5037220e VP8LSubtractGreenFromBlueAndRed_C: clear int sanitizer warnings
+2ee786c7 upsampling_sse2.c: clear int sanitizer warnings
+4cc157d4 ParseOptionalChunks: clear int sanitizer warning
+892cf033 BuildHuffmanTable: clear int sanitizer warning
+3a9a4d45 VP8GetSigned: clear int sanitizer warnings
+704a3d0a dsp/lossless.c: quiet int sanitizer warnings
+1a6c109c WebPPictureHasTransparency: add missing pointer check
+c626e7d5 cwebp: fix WebPPictureHasTransparency call
+866e349c Merge tag 'v1.2.4'
+c170df38 Merge "Create libsharpyuv.a in makefile.unix." into main
+9d7ff74a Create libsharpyuv.a in makefile.unix.
+0d1f1254 update ChangeLog (tag: v1.2.4)
+fcbc2d78 Merge "doc/*.txt: restrict code to 69 columns" into main
+4ad0e189 Merge "webp-container-spec.txt: normalize fourcc spelling" into main
+980d2488 update NEWS
+9fde8127 bump version to 1.2.4
+7a0a9935 doc/*.txt: restrict code to 69 columns
+c040a615 webp-container-spec.txt: normalize fourcc spelling
+aff1c546 dsp,x86: normalize types w/_mm_cvtsi128_si32 calls
+ab540ae0 dsp,x86: normalize types w/_mm_cvtsi32_si128 calls
+8980362e dsp,x86: normalize types w/_mm_set* calls (2)
+e626925c lossless: fix crunch mode w/WEBP_REDUCE_SIZE
+83539239 dsp,x86: normalize types w/_mm_set* calls
+8a4576ce webp-container-spec.txt: replace &amp; with &
+db870881 Merge "webp-container-spec.txt: make reserved 0 values a MUST" into main
+01d7d378 webp-lossless-bitstream-spec: number all sections
+337cf69f webp-lossless-bitstream-spec: mv Nomenclature after Intro
+79be856e Merge changes I7111d1f7,I872cd62c into main
+5b87983a webp-container-spec.txt: make reserved 0 values a MUST
+bd939123 Merge changes I7a25b1a6,I51b2c2a0,I87d0cbcf,I6ec60af6,I0a3fe9dc into main
+04764b56 libwebp.pc: add libsharpyuv to requires
+7deee810 libsharpyuv: add pkg-config file
+1a64a7e6 webp-container-spec.txt: clarify some SHOULDs
+bec2c88a webp-container-spec.txt: move ChunkHeader to terminology
+c9359332 webp-container-spec.txt: clarify 'VP8 '/'XMP ' fourccs
+70fe3063 webp-container-spec.txt: rightsize table entries
+ddbf3f3f webp-container-spec.txt: update 'key words' text
+c151e95b utils.h,WEBP_ALIGN: make bitmask unsigned
+748e92bb add WebPInt32ToMem
+3fe15b67 Merge "Build libsharpyuv as a full installable library." into main
+4f402f34 add WebPMemToInt32
+a3b68c19 Build libsharpyuv as a full installable library.
+b4994eaa CMake: set rpath for shared objects
+94cd7117 Merge "CMake: fix dylib versioning" into main
+e91451b6 Fix the lossless specs a bit more.
+231bdfb7 CMake: fix dylib versioning
+bfad7ab5 CMakeLists.txt: correct libwebpmux name in WebPConfig.cmake
+c2e3fd30 Revert "cmake: fix webpmux lib name for cmake linking"
+7366f7f3 Merge "lossless: fix crunch mode w/WEBP_REDUCE_SIZE" into main
+84163d9d lossless: fix crunch mode w/WEBP_REDUCE_SIZE
+d01c1eb3 webp-lossless-bitstream-spec,cosmetics: normalize capitalization
+8813ca8e Merge tag 'v1.2.3'
+3c4a0fbf update ChangeLog (tag: v1.2.3)
+56a480e8 dsp/cpu.h: add missing extern "C"
+62b45bdd update ChangeLog (tag: v1.2.3-rc1)
+8764ec7a Merge changes Idb037953,Id582e395 into 1.2.3
+bcb872c3 vwebp: fix file name display in windows unicode build
+67c44ac5 webpmux: fix -frame option in windows unicode build
+8278825a makefile.unix: add sharpyuv objects to clean target
+14a49e01 update NEWS
+34b1dc33 bump version to 1.2.3
+0b397fda update AUTHORS
+c16488ac update .mailmap
+5a2d929c Merge "unicode.h: set console mode before using wprintf" into main
+169f867f unicode.h: set console mode before using wprintf
+a94b855c Merge "libsharpyuv: add version defines" into main
+f83bdb52 libsharpyuv: add version defines
+bef0d797 unicode_gif.h: fix -Wdeclaration-after-statement
+404c1622 Rename Huffman coding to prefix coding in the bitstream spec
+8895f8a3 Merge "run_static_analysis.sh: fix scan-build archive path" into main
+92a673d2 Merge "Add -fvisibility=hidden flag in CMakeLists." into main
+67c1d722 Merge "add WEBP_MSAN" into main
+1124ff66 Add -fvisibility=hidden flag in CMakeLists.
+e15b3560 add WEBP_MSAN
+ec9e782a sharpyuv: remove minimum image size from sharpyuv library
+7bd07f3b run_static_analysis.sh: fix scan-build archive path
+5ecee06f Merge "sharpyuv: increase precision of gamma<->linear conversion" into main
+f81dd7d6 Merge changes I3d17d529,I53026880,I1bd61639,I6bd4b25d,Icfec8fba into main
+2d607ee6 sharpyuv: increase precision of gamma<->linear conversion
+266cbbc5 sharpyuv: add 32bit version of SharpYuvFilterRow.
+9fc12274 CMake: add src to webpinfo includes
+7d18f40a CMake: add WEBP_BUILD_WEBPINFO to list of checks for exampleutil
+11309aa5 CMake: add WEBP_BUILD_WEBPMUX to list of checks for exampleutil
+4bc762f7 CMake: link imageioutil to exampleutil after defined
+0d1b9bc4 WEBP_DEP_LIBRARIES: use Threads::Threads
+20ef48f0 Merge "sharpyuv: add support for 10/12/16 bit rgb and 10/12 bit yuv." into main
+93c54371 sharpyuv: add support for 10/12/16 bit rgb and 10/12 bit yuv.
+53cf2b49 normalize WebPValidatePicture declaration w/definition
+d3006f4b sharpyuv: slightly improve precision
+ea967098 Merge changes Ia01bd397,Ibf3771af into main
+11bc8410 Merge changes I2d317c4b,I9e77f6db into main
+30453ea4 Add an internal WebPValidatePicture.
+6c43219a Some renamings for consistency.
+4f59fa73 update .mailmap
+e74f8a62 webp-lossless-bitstream-spec,cosmetics: normalize range syntax
+5a709ec0 webp-lossless-bitstream-spec,cosmetics: fix code typo
+a2093acc webp-lossless-bitstream-spec: add amendment note
+86c66930 webp-lossless-bitstream-spec: fix BNF
+232f22da webp-lossless-bitstream-spec: fix 'simple code' snippet
+44dd765d webp-lossless-bitstream-spec: fix ColorTransform impl
+7a7e33e9 webp-lossless-bitstream-spec: fix TR-pixel right border note
+86f94ee0 Update lossless spec with Huffman codes.
+a3927cc8 sharpyuv.c,cosmetics: fix indent
+6c45cef7 Make sure the stride has a minimum value in the importer.
+0c8b0e67 sharpyuv: cleanup/cosmetic changes
+dc3841e0 {histogram,predictor}_enc: quiet int -> float warnings
+a19a25bb Replace doubles by floats in lossless misc cost estimations.
+42888f6c Add an option to enable static builds.
+7efcf3cc Merge "Fix typo in color constants: Marix -> Matrix" into main
+8f4b5c62 Fix typo in color constants: Marix -> Matrix
+90084d84 Merge "demux,IsValidExtendedFormat: remove unused variable" into main
+ed643f61 Merge changes I452d2485,Ic6d75475 into main
+8fa053d1 Rename SharpYUV to SharpYuv for consistency.
+99a87562 SharpYuvComputeConversionMatrix: quiet int->float warnings
+deb426be Makefile.vc: add sharpyuv_csp.obj to SHARPYUV_OBJS
+779597d4 demux,IsValidExtendedFormat: remove unused variable
+40e8aa57 Merge "libsharpyuv: add colorspace utilities" into main
+01a05de1 libsharpyuv: add colorspace utilities
+2de4b05a Merge changes Id9890a60,I376d81e6,I1c958838 into main
+b8bca81f Merge "configure.ac: use LT_INIT if available" into main
+e8e77b9c Merge changes I479bc487,I39864691,I5d486c2c,I186d13be into main
+7e7d5d50 Merge ".gitignore: add Android Studio & VS code dirs" into main
+10c50848 normalize label indent
+89f774e6 mux{edit,internal}: fix leaks on error
+2d3293ad ExUtilInitCommandLineArguments: fix leak on error
+ec34fd70 anim_util: fix leaks on error
+e4717287 gif2webp: fix segfault on OOM
+e3cfafaf GetBackwardReferences: fail on alloc error
+a828a59b BackwardReferencesHashChainDistanceOnly: fix segfault on OOM
+fe153fae VP8LEncodeStream: fix segfault on OOM
+919acc0e .gitignore: add Android Studio & VS code dirs
+efa0731b configure.ac: use LT_INIT if available
+0957fd69 tiffdec: add grayscale support
+e685feef Merge "Make libsharpyuv self-contained by removing dependency on cpu.c" into main
+841960b6 Make libsharpyuv self-contained by removing dependency on cpu.c
+617cf036 image_dec: add WebPGetEnabledInputFileFormats()
+7a68afaa Let SharpArgbToYuv caller pass in an RGB>YUV conversion matrix.
+34bb332c man/cwebp.1: add note about crop/resize order
+f0e9351c webp-lossless-bitstream-spec,cosmetics: fix some typos
+5ccbd6ed vp8l_dec.c,cosmetics: fix a few typos
+c3d0c2d7 fix ios build scripts after sharpyuv dep added
+d0d2292e Merge "Make libwebp depend on libsharpyuv." into main
+03d12190 alpha_processing_neon.c: fix 0x01... typo
+d55d447c Make libwebp depend on libsharpyuv.
+e4cbcdd2 Fix lossless encoding for MIPS.
+924e7ca6 alpha_processing_neon.c: fix Dispatch/ExtractAlpha_NEON
+0fa0ea54 Makefile.vc: use /MANIFEST:EMBED
+29cc95ce Basic version of libsharpyuv in libwebp, in C.
+a30f2190 examples/webpmux.c: fix a couple of typos
+66b3ce23 Fix bad overflow check in ReadTIFF()
+54e61a38 Markdownify libwebp docs and reorganize them.
+b4533deb CMakeLists.txt,cosmetics: break long line
+b9d2f9cd quant_enc.c: use WEBP_RESTRICT qualifier
+ec178f2c Add progress hook granularity in lossless
+26139c73 Rename MAX_COST to MAX_BIT_COST in histogram_enc.c
+13b82816 cmake: fix webpmux lib name for cmake linking
+88b6a396 webp-container-spec.txt,cosmetics: normalize formatting
+6f496540 Merge tag 'v1.2.2'
+4074acf8 dsp.h: bump msvc arm64 version requirement to 16.6
+b0a86089 update ChangeLog (tag: v1.2.2)
 6db8248c libwebp: Fix VP8EncTokenLoop() progress
 827a307f BMP enc: fix the transparency case
+db25f1b4 libwebp: Fix VP8EncTokenLoop() progress
 286e7fce libwebp: do not destroy jpeg codec twice on error
+6e8a4126 libwebp: do not destroy jpeg codec twice on error
+faf21968 Merge "BMP enc: fix the transparency case" into main
+480cd51d BMP enc: fix the transparency case
 9195ea05 update ChangeLog (tag: v1.2.2-rc2)
 4acae017 update NEWS
 883f0633 man/img2webp.1: update date
 567e1f44 Reword img2webp synopsis command line
+1b0c15db man/img2webp.1: update date
+17bade38 Merge "Reword img2webp synopsis command line" into main
+a80954a1 Reword img2webp synopsis command line
 f084244d anim_decode: fix alpha blending with big-endian
 b217b4ff webpinfo: fix fourcc comparison w/big-endian
+ec497b75 Merge "anim_decode: fix alpha blending with big-endian" into main
+e4886716 anim_decode: fix alpha blending with big-endian
+e3cb052c webpinfo: fix fourcc comparison w/big-endian
+a510fedb patch-check: detect duplicated files
 f035d2e4 update ChangeLog (tag: v1.2.2-rc1)
 7031946a update NEWS
 973390b6 bump version to 1.2.2
@@ -45,7 +539,7 @@ e23cd548 dsp.h: enable NEON w/VS2019+ ARM64 targets
 42592af8 webp,cmake: Remove unnecessary include dirs
 e298e05f Add patch-check steps in PRESUBMIT.py
 29148919 Merge tag 'v1.2.1'
-9ce5843d update ChangeLog (tag: v1.2.1, origin/1.2.1)
+9ce5843d update ChangeLog (tag: v1.2.1)
 d9191588 fuzzer/*: normalize src/ includes
 c5bc3624 fuzzer/*: normalize src/ includes
 53b6f762 fix indent
@@ -224,7 +718,7 @@ a99078c1 remove call to MBAnalyzeBestIntra4Mode for method >= 5
 6a0ff358 Enc: add a qmin / qmax range for quality factor
 0fa56f30 Merge tag 'v1.1.0'
 6cf504d0 PNM decoding: handle max_value != 255
-d7844e97 update ChangeLog (tag: v1.1.0-rc2, tag: v1.1.0, origin/1.1.0)
+d7844e97 update ChangeLog (tag: v1.1.0-rc2, tag: v1.1.0)
 7f006436 Makefile.vc: fix webp_quality.exe link
 cf047e83 Makefile.vc: fix webp_quality.exe link
 c074c653 update NEWS
@@ -869,7 +1363,7 @@ b016cb91 NEON: faster fancy upsampling
 f04eb376 Merge tag 'v0.5.2'
 341d711c NEON: 5% faster conversion to RGB565 and RGBA4444
 abb54827 remove Clang warnings with unused arch arguments.
-ece9684f update ChangeLog (tag: v0.5.2-rc2, tag: v0.5.2, origin/0.5.2)
+ece9684f update ChangeLog (tag: v0.5.2-rc2, tag: v0.5.2)
 aa7744ca anim_util: quiet implicit conv warnings in 32-bit
 d9120271 jpegdec: correct ContextFill signature
 24eb3940 Remove some errors when compiling the code as C++.
@@ -1156,7 +1650,7 @@ bbb6ecd9 Merge "Add MSA optimized distortion functions"
 c0991a14 io,EmitRescaledAlphaYUV: factor out a common expr
 48bf5ed1 build.gradle: remove tab
 bfef6c9f Merge tag 'v0.5.1'
-3d97bb75 update ChangeLog (tag: v0.5.1, origin/0.5.1)
+3d97bb75 update ChangeLog (tag: v0.5.1)
 deb54d91 Clarify the expected 'config' lifespan in WebPIDecode()
 435308e0 Add MSA optimized encoder transform functions
 dce64bfa Add MSA optimized alpha filter functions

Makefile.am

@@ -1,5 +1,5 @@
 ACLOCAL_AMFLAGS = -I m4
-SUBDIRS = src imageio man
+SUBDIRS = sharpyuv src imageio man
 EXTRA_DIST = COPYING autogen.sh
 
 if BUILD_EXTRAS

Makefile.vc

@@ -5,12 +5,15 @@ LIBWEBPDECODER_BASENAME = libwebpdecoder
 LIBWEBP_BASENAME = libwebp
 LIBWEBPMUX_BASENAME = libwebpmux
 LIBWEBPDEMUX_BASENAME = libwebpdemux
+LIBSHARPYUV_BASENAME = libsharpyuv
 
 !IFNDEF ARCH
 !IF ! [ cl 2>&1 | find "x86" > NUL ]
 ARCH = x86
 !ELSE IF ! [ cl 2>&1 | find "x64" > NUL ]
 ARCH = x64
+!ELSE IF ! [ cl 2>&1 | find "ARM64" > NUL ]
+ARCH = ARM64
 !ELSE IF ! [ cl 2>&1 | find "ARM" > NUL ]
 ARCH = ARM
 !ELSE
@@ -31,12 +34,11 @@ CCNODBG    = cl.exe $(NOLOGO) /O2 /DNDEBUG
 CCDEBUG    = cl.exe $(NOLOGO) /Od /Zi /D_DEBUG /RTC1
 CFLAGS     = /I. /Isrc $(NOLOGO) /W3 /EHsc /c
 CFLAGS     = $(CFLAGS) /DWIN32 /D_CRT_SECURE_NO_WARNINGS /DWIN32_LEAN_AND_MEAN
-LDFLAGS    = /LARGEADDRESSAWARE /MANIFEST /NXCOMPAT /DYNAMICBASE
+LDFLAGS    = /LARGEADDRESSAWARE /MANIFEST:EMBED /NXCOMPAT /DYNAMICBASE
 LDFLAGS    = $(LDFLAGS) $(PLATFORM_LDFLAGS)
 LNKDLL     = link.exe /DLL $(NOLOGO)
 LNKEXE     = link.exe $(NOLOGO)
 LNKLIB     = lib.exe $(NOLOGO)
-MT         = mt.exe $(NOLOGO)
 RCNODBG    = rc.exe $(NOLOGO) /l"0x0409"  # 0x409 = U.S. English
 RCDEBUG    = $(RCNODBG) /D_DEBUG
 
@@ -82,6 +84,7 @@ OUTPUT_DIRS = $(DIRBIN) $(DIRINC) $(DIRLIB) \
               $(DIROBJ)\extras \
               $(DIROBJ)\imageio \
               $(DIROBJ)\mux \
+              $(DIROBJ)\sharpyuv \
               $(DIROBJ)\utils \
 
 # Target configuration
@@ -96,6 +99,7 @@ LIBWEBPDECODER_BASENAME = $(LIBWEBPDECODER_BASENAME)_debug
 LIBWEBP_BASENAME = $(LIBWEBP_BASENAME)_debug
 LIBWEBPMUX_BASENAME = $(LIBWEBPMUX_BASENAME)_debug
 LIBWEBPDEMUX_BASENAME = $(LIBWEBPDEMUX_BASENAME)_debug
+LIBSHARPYUV_BASENAME = $(LIBSHARPYUV_BASENAME)_debug
 !ELSE IF "$(CFG)" == "release-dynamic"
 CC        = $(CCNODBG)
 RC        = $(RCNODBG)
@@ -109,6 +113,7 @@ LIBWEBPDECODER_BASENAME = $(LIBWEBPDECODER_BASENAME)_debug
 LIBWEBP_BASENAME = $(LIBWEBP_BASENAME)_debug
 LIBWEBPMUX_BASENAME = $(LIBWEBPMUX_BASENAME)_debug
 LIBWEBPDEMUX_BASENAME = $(LIBWEBPDEMUX_BASENAME)_debug
+LIBSHARPYUV_BASENAME = $(LIBSHARPYUV_BASENAME)_debug
 !ENDIF
 
 !IF "$(STATICLIBBUILD)" == "TRUE"
@@ -118,13 +123,14 @@ LIBWEBPDECODER = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME).lib
 LIBWEBP = $(DIRLIB)\$(LIBWEBP_BASENAME).lib
 LIBWEBPMUX = $(DIRLIB)\$(LIBWEBPMUX_BASENAME).lib
 LIBWEBPDEMUX = $(DIRLIB)\$(LIBWEBPDEMUX_BASENAME).lib
+LIBSHARPYUV = $(DIRLIB)\$(LIBSHARPYUV_BASENAME).lib
 !ELSE IF "$(DLLBUILD)" == "TRUE"
-DLLINC = webp_dll.h
-CC     = $(CC) /I$(DIROBJ) /FI$(DLLINC) $(RTLIB) /DWEBP_DLL
+CC     = $(CC) /I$(DIROBJ) $(RTLIB) /DWEBP_DLL
 LIBWEBPDECODER = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME)_dll.lib
 LIBWEBP = $(DIRLIB)\$(LIBWEBP_BASENAME)_dll.lib
 LIBWEBPMUX = $(DIRLIB)\$(LIBWEBPMUX_BASENAME)_dll.lib
 LIBWEBPDEMUX = $(DIRLIB)\$(LIBWEBPDEMUX_BASENAME)_dll.lib
+LIBSHARPYUV = $(DIRLIB)\$(LIBSHARPYUV_BASENAME)_dll.lib
 LIBWEBP_PDBNAME = $(DIROBJ)\$(LIBWEBP_BASENAME)_dll.pdb
 CFGSET = TRUE
 !ENDIF
@@ -174,6 +180,15 @@ CFLAGS = $(CFLAGS) /D_UNICODE /DUNICODE
 # A config was provided, so the library can be built.
 #
 
+SHARPYUV_OBJS = \
+    $(DIROBJ)\sharpyuv\sharpyuv.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_cpu.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_csp.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_dsp.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_gamma.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_neon.obj \
+    $(DIROBJ)\sharpyuv\sharpyuv_sse2.obj \
+
 DEC_OBJS = \
     $(DIROBJ)\dec\alpha_dec.obj \
     $(DIROBJ)\dec\buffer_dec.obj \
@@ -308,6 +323,7 @@ ENC_OBJS = \
 EXTRAS_OBJS = \
     $(DIROBJ)\extras\extras.obj \
     $(DIROBJ)\extras\quality_estimate.obj \
+    $(DIROBJ)\extras\sharpyuv_risk_table.obj \
 
 IMAGEIO_UTIL_OBJS = \
     $(DIROBJ)\imageio\imageio_util.obj \
@@ -323,6 +339,7 @@ UTILS_DEC_OBJS = \
     $(DIROBJ)\utils\color_cache_utils.obj \
     $(DIROBJ)\utils\filters_utils.obj \
     $(DIROBJ)\utils\huffman_utils.obj \
+    $(DIROBJ)\utils\palette.obj \
     $(DIROBJ)\utils\quant_levels_dec_utils.obj \
     $(DIROBJ)\utils\rescaler_utils.obj \
     $(DIROBJ)\utils\random_utils.obj \
@@ -335,12 +352,13 @@ UTILS_ENC_OBJS = \
     $(DIROBJ)\utils\quant_levels_utils.obj \
 
 LIBWEBPDECODER_OBJS = $(DEC_OBJS) $(DSP_DEC_OBJS) $(UTILS_DEC_OBJS)
-LIBWEBP_OBJS = $(LIBWEBPDECODER_OBJS) $(ENC_OBJS) $(DSP_ENC_OBJS) \
-               $(UTILS_ENC_OBJS) $(DLL_OBJS)
+LIBWEBP_OBJS = $(LIBWEBPDECODER_OBJS) $(ENC_OBJS) \
+               $(DSP_ENC_OBJS) $(UTILS_ENC_OBJS) $(DLL_OBJS)
 LIBWEBPMUX_OBJS = $(MUX_OBJS) $(LIBWEBPMUX_OBJS)
 LIBWEBPDEMUX_OBJS = $(DEMUX_OBJS) $(LIBWEBPDEMUX_OBJS)
+LIBSHARPYUV_OBJS = $(SHARPYUV_OBJS)
 
-OUT_LIBS = $(LIBWEBPDECODER) $(LIBWEBP)
+OUT_LIBS = $(LIBWEBPDECODER) $(LIBWEBP) $(LIBSHARPYUV)
 !IF "$(ARCH)" == "ARM"
 ex: $(OUT_LIBS)
 all: ex
@@ -368,7 +386,7 @@ $(DIRBIN)\anim_dump.exe: $(EX_GIF_DEC_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
 $(DIRBIN)\anim_dump.exe: $(IMAGEIO_ENC_OBJS)
 $(DIRBIN)\cwebp.exe: $(DIROBJ)\examples\cwebp.obj $(IMAGEIO_DEC_OBJS)
 $(DIRBIN)\cwebp.exe: $(IMAGEIO_UTIL_OBJS)
-$(DIRBIN)\cwebp.exe: $(LIBWEBPDEMUX)
+$(DIRBIN)\cwebp.exe: $(LIBWEBPDEMUX) $(LIBSHARPYUV)
 $(DIRBIN)\dwebp.exe: $(DIROBJ)\examples\dwebp.obj $(IMAGEIO_DEC_OBJS)
 $(DIRBIN)\dwebp.exe: $(IMAGEIO_ENC_OBJS)
 $(DIRBIN)\dwebp.exe: $(IMAGEIO_UTIL_OBJS)
@@ -386,7 +404,7 @@ $(DIRBIN)\webpmux.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS) $(LIBWEBP)
 $(DIRBIN)\img2webp.exe: $(DIROBJ)\examples\img2webp.obj $(LIBWEBPMUX)
 $(DIRBIN)\img2webp.exe: $(IMAGEIO_DEC_OBJS)
 $(DIRBIN)\img2webp.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS)
-$(DIRBIN)\img2webp.exe: $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\img2webp.exe: $(LIBWEBPDEMUX) $(LIBWEBP) $(LIBSHARPYUV)
 $(DIRBIN)\get_disto.exe: $(DIROBJ)\extras\get_disto.obj
 $(DIRBIN)\get_disto.exe: $(IMAGEIO_DEC_OBJS) $(IMAGEIO_UTIL_OBJS)
 $(DIRBIN)\get_disto.exe: $(LIBWEBPDEMUX) $(LIBWEBP)
@@ -409,17 +427,16 @@ $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS): $(OUTPUT_DIRS)
 $(IMAGEIO_DEC_OBJS) $(IMAGEIO_ENC_OBJS) $(EXTRAS_OBJS): $(OUTPUT_DIRS)
 !ENDIF  # ARCH == ARM
 
+$(LIBSHARPYUV): $(LIBSHARPYUV_OBJS)
 $(LIBWEBPDECODER): $(LIBWEBPDECODER_OBJS)
-$(LIBWEBP): $(LIBWEBP_OBJS)
+$(LIBWEBP): $(LIBWEBP_OBJS) $(LIBSHARPYUV)
 $(LIBWEBPMUX): $(LIBWEBPMUX_OBJS)
 $(LIBWEBPDEMUX): $(LIBWEBPDEMUX_OBJS)
 
-$(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS): $(OUTPUT_DIRS)
+$(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS) $(LIBSHARPYUV_OBJS): \
+    $(OUTPUT_DIRS)
 
 !IF "$(DLLBUILD)" == "TRUE"
-$(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS): \
-    $(DIROBJ)\$(DLLINC)
-
 {$(DIROBJ)}.c{$(DIROBJ)}.obj:
 	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$@  $<
 
@@ -429,20 +446,20 @@ $(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS): \
 	$(RC) /fo$@ $<
 {src\mux}.rc{$(DIROBJ)\mux}.res:
 	$(RC) /fo$@ $<
+{sharpyuv}.rc{$(DIROBJ)\sharpyuv}.res:
+	$(RC) /fo$@ $<
 
-$(LIBWEBP): $(DIROBJ)\$(LIBWEBP_BASENAME:_debug=).res
+$(LIBSHARPYUV): $(DIROBJ)\sharpyuv\$(LIBSHARPYUV_BASENAME:_debug=).res
+$(LIBWEBP): $(LIBSHARPYUV) $(DIROBJ)\$(LIBWEBP_BASENAME:_debug=).res
 $(LIBWEBPDECODER): $(DIROBJ)\$(LIBWEBPDECODER_BASENAME:_debug=).res
 $(LIBWEBPMUX): $(LIBWEBP) $(DIROBJ)\mux\$(LIBWEBPMUX_BASENAME:_debug=).res
 $(LIBWEBPDEMUX): $(LIBWEBP) $(DIROBJ)\demux\$(LIBWEBPDEMUX_BASENAME:_debug=).res
 
-$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX):
+$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX) $(LIBSHARPYUV):
 	$(LNKDLL) /out:$(DIRBIN)\$(@B:_dll=.dll) /implib:$@ $(LFLAGS) $**
 	-xcopy $(DIROBJ)\*.pdb $(DIRLIB) /y
-
-clean::
-	@-erase /s $(DIROBJ)\$(DLLINC) 2> NUL
 !ELSE
-$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX):
+$(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX) $(LIBSHARPYUV):
 	$(LNKLIB) /out:$@ $**
 	-xcopy $(DIROBJ)\*.pdb $(DIRLIB) /y
 !ENDIF
@@ -450,13 +467,6 @@ $(LIBWEBPDECODER) $(LIBWEBP) $(LIBWEBPMUX) $(LIBWEBPDEMUX):
 $(OUTPUT_DIRS):
 	@if not exist "$(@)" mkdir "$(@)"
 
-# generate a helper include to define WEBP_EXTERN suitable for the DLL build
-$(DIROBJ)\$(DLLINC):
-	@echo #ifndef WEBP_DLL_H_ > $@
-	@echo #define WEBP_DLL_H_ >> $@
-	@echo #define WEBP_EXTERN __declspec(dllexport) >> $@
-	@echo #endif  /* WEBP_DLL_H_ */ >> $@
-
 .SUFFIXES: .c .obj .res .exe
 # File-specific flag builds. Note batch rules take precedence over wildcards,
 # so for now name each file individually.
@@ -482,6 +492,8 @@ $(DIROBJ)\examples\gifdec.obj: examples\gifdec.c
 	$(CC) $(CFLAGS) /Fd$(DIROBJ)\extras\ /Fo$(DIROBJ)\extras\ $<
 {imageio}.c{$(DIROBJ)\imageio}.obj::
 	$(CC) $(CFLAGS) /Fd$(DIROBJ)\imageio\ /Fo$(DIROBJ)\imageio\ $<
+{sharpyuv}.c{$(DIROBJ)\sharpyuv}.obj::
+	$(CC) $(CFLAGS) /Fd$(DIROBJ)\sharpyuv\ /Fo$(DIROBJ)\sharpyuv\ $<
 {src\dec}.c{$(DIROBJ)\dec}.obj::
 	$(CC) $(CFLAGS) /Fd$(LIBWEBP_PDBNAME) /Fo$(DIROBJ)\dec\ $<
 {src\demux}.c{$(DIROBJ)\demux}.obj::
@@ -502,13 +514,9 @@ LNKLIBS     = $(LNKLIBS) Shell32.lib
 
 {$(DIROBJ)\examples}.obj{$(DIRBIN)}.exe:
 	$(LNKEXE) $(LDFLAGS) /OUT:$@ $** $(LNKLIBS)
-	$(MT) -manifest $@.manifest -outputresource:$@;1
-	del $@.manifest
 
 {$(DIROBJ)\extras}.obj{$(DIRBIN)}.exe:
 	$(LNKEXE) $(LDFLAGS) /OUT:$@ $** $(LNKLIBS)
-	$(MT) -manifest $@.manifest -outputresource:$@;1
-	del $@.manifest
 
 clean::
 	@-erase /s $(DIROBJ)\*.dll 2> NUL

NEWS

@@ -1,3 +1,59 @@
+- 4/12/2024: version 1.4.0
+  This is a binary compatible release.
+  * API changes:
+    - libwebpmux: WebPAnimEncoderSetChunk, WebPAnimEncoderGetChunk,
+                  WebPAnimEncoderDeleteChunk
+    - libsharpyuv: SharpYuvOptionsInit, SharpYuvConvertWithOptions
+    - extras: SharpYuvEstimate420Risk
+  * further security related hardening in libwebp & examples
+  * some minor optimizations in the lossless encoder
+  * added WEBP_NODISCARD to report unused result warnings; enable with
+    -DWEBP_ENABLE_NODISCARD=1
+  * improvements and corrections in webp-container-spec.txt and
+    webp-lossless-bitstream-spec.txt (#611)
+  * miscellaneous warning, bug & build fixes (#615, #619, #632, #635)
+
+- 9/13/2023: version 1.3.2
+  This is a binary compatible release.
+  * security fix for lossless decoder (chromium: #1479274, CVE-2023-4863)
+
+- 6/23/2023: version 1.3.1
+  This is a binary compatible release.
+  * security fixes for lossless encoder (#603, chromium: #1420107, #1455619,
+    CVE-2023-1999)
+  * improve error reporting through WebPPicture error codes
+  * fix upsampling for RGB565 and RGBA4444 in NEON builds
+  * img2webp: add -sharp_yuv & -near_lossless
+  * Windows builds:
+    - fix compatibility with clang-cl (#607)
+    - improve Arm64 performance with cl.exe
+    - add Arm64EC support
+  * fix webp_js with emcc >= 3.1.27 (stack size change, #614)
+  * CMake fixes (#592, #610, #612)
+  * further updates to the container and lossless bitstream docs (#581, #611)
+
+- 12/16/2022: version 1.3.0
+  This is a binary compatible release.
+  * add libsharpyuv, which exposes -sharp_yuv/config.use_sharp_yuv
+    functionality to other libraries; libwebp now depends on this library
+  * major updates to the container and lossless bitstream docs (#448, #546,
+    #551)
+  * miscellaneous warning, bug & build fixes (#576, #583, #584)
+
+- 8/4/2022: version 1.2.4
+  This is a binary compatible release.
+  * restore CMake libwebpmux target name for compatibility with 1.2.2 (#575)
+  * fix lossless crunch mode encoding with WEBP_REDUCE_SIZE
+    (chromium: #1345547, #1345595, #1345772, #1345804)
+
+- 6/30/2022: version 1.2.3
+  This is a binary compatible release.
+  * security fix for lossless encoder (#565, chromium:1313709)
+  * improved progress granularity in WebPReportProgress() when using lossless
+  * improved precision in Sharp YUV (-sharp_yuv) conversion
+  * many corrections to webp-lossless-bitstream-spec.txt (#551)
+  * crash/leak fixes on error/OOM and other bug fixes (#558, #563, #569, #573)
+
 - 1/11/2022: version 1.2.2
   This is a binary compatible release.
   * webpmux: add "-set bgcolor A,R,G,B"

PRESUBMIT.py

@@ -41,6 +41,7 @@ _BASH_INDENTATION = "2"
 _GIT_COMMIT_SUBJECT_LENGTH = 65
 _INCLUDE_BASH_FILES_ONLY = [r".*\.sh$"]
 _INCLUDE_MAN_FILES_ONLY = [r"man/.+\.1$"]
+_INCLUDE_SOURCE_FILES_ONLY = [r".*\.[ch]$"]
 _LIBWEBP_MAX_LINE_LENGTH = 80
 
 
@@ -72,6 +73,35 @@ def _CheckCommitSubjectLength(input_api, output_api):
   return output_api.PresubmitResult("%s\n (%4.2fs) success" % (name, duration))
 
 
+def _CheckDuplicateFiles(input_api, output_api):
+  """Ensures there are not repeated filenames."""
+  all_files = []
+  for f in input_api.change.AllFiles():
+    for include_file in _INCLUDE_SOURCE_FILES_ONLY:
+      if re.match(include_file, f):
+        all_files.append(f)
+        break
+
+  basename_to_path = {}
+  for f in all_files:
+    basename_file = input_api.basename(f)
+    if basename_file in basename_to_path:
+      basename_to_path[basename_file].append(f)
+    else:
+      basename_to_path[basename_file] = [f]
+
+  dupes = []
+  for files in basename_to_path.values():
+    if len(files) > 1:
+      dupes.extend(files)
+
+  if dupes:
+    return output_api.PresubmitError(
+        "Duplicate source files, rebase or rename some to make them unique:\n%s"
+        % dupes)
+  return output_api.PresubmitResult("No duplicates, success\n")
+
+
 def _GetFilesToSkip(input_api):
   return list(input_api.DEFAULT_FILES_TO_SKIP) + [
       r"swig/.*\.py$",
@@ -154,6 +184,7 @@ def _CommonChecks(input_api, output_api):
       input_api.canned_checks.CheckChangeHasNoStrayWhitespace(
           input_api, output_api))
   results.append(_CheckCommitSubjectLength(input_api, output_api))
+  results.append(_CheckDuplicateFiles(input_api, output_api))
 
   source_file_filter = lambda x: input_api.FilterSourceFile(
       x, files_to_skip=_GetFilesToSkip(input_api))

README

@@ -1,795 +0,0 @@
-          __   __  ____  ____  ____
-         /  \\/  \/  _ \/  _ )/  _ \
-         \       /   __/  _  \   __/
-          \__\__/\____/\_____/__/ ____  ___
-                / _/ /    \    \ /  _ \/ _/
-               /  \_/   / /   \ \   __/  \__
-               \____/____/\_____/_____/____/v1.2.2
-
-Description:
-============
-
-WebP codec: library to encode and decode images in WebP format. This package
-contains the library that can be used in other programs to add WebP support,
-as well as the command line tools 'cwebp' and 'dwebp'.
-
-See https://developers.google.com/speed/webp
-
-The latest source tree is available at
-https://chromium.googlesource.com/webm/libwebp
-
-It is released under the same license as the WebM project.
-See https://www.webmproject.org/license/software/ or the
-"COPYING" file for details. An additional intellectual
-property rights grant can be found in the file PATENTS.
-
-Building:
-=========
-
-Windows build:
---------------
-
-By running:
-
-  nmake /f Makefile.vc CFG=release-static RTLIBCFG=static OBJDIR=output
-
-the directory output\release-static\(x64|x86)\bin will contain the tools
-cwebp.exe and dwebp.exe. The directory output\release-static\(x64|x86)\lib will
-contain the libwebp static library.
-The target architecture (x86/x64) is detected by Makefile.vc from the Visual
-Studio compiler (cl.exe) available in the system path.
-
-Unix build using makefile.unix:
--------------------------------
-
-On platforms with GNU tools installed (gcc and make), running
-
-  make -f makefile.unix
-
-will build the binaries examples/cwebp and examples/dwebp, along
-with the static library src/libwebp.a. No system-wide installation
-is supplied, as this is a simple alternative to the full installation
-system based on the autoconf tools (see below).
-Please refer to makefile.unix for additional details and customizations.
-
-Using autoconf tools:
----------------------
-Prerequisites:
-A compiler (e.g., gcc), make, autoconf, automake, libtool.
-On a Debian-like system the following should install everything you need for a
-minimal build:
-$ sudo apt-get install gcc make autoconf automake libtool
-
-When building from git sources, you will need to run autogen.sh to generate the
-configure script.
-
-./configure
-make
-make install
-
-should be all you need to have the following files
-
-/usr/local/include/webp/decode.h
-/usr/local/include/webp/encode.h
-/usr/local/include/webp/types.h
-/usr/local/lib/libwebp.*
-/usr/local/bin/cwebp
-/usr/local/bin/dwebp
-
-installed.
-
-Note: A decode-only library, libwebpdecoder, is available using the
-'--enable-libwebpdecoder' flag. The encode library is built separately and can
-be installed independently using a minor modification in the corresponding
-Makefile.am configure files (see comments there). See './configure --help' for
-more options.
-
-Building for MIPS Linux:
-------------------------
-MIPS Linux toolchain stable available releases can be found at:
-https://community.imgtec.com/developers/mips/tools/codescape-mips-sdk/available-releases/
-
-# Add toolchain to PATH
-export PATH=$PATH:/path/to/toolchain/bin
-
-# 32-bit build for mips32r5 (p5600)
-HOST=mips-mti-linux-gnu
-MIPS_CFLAGS="-O3 -mips32r5 -mabi=32 -mtune=p5600 -mmsa -mfp64 \
-  -msched-weight -mload-store-pairs -fPIE"
-MIPS_LDFLAGS="-mips32r5 -mabi=32 -mmsa -mfp64 -pie"
-
-# 64-bit build for mips64r6 (i6400)
-HOST=mips-img-linux-gnu
-MIPS_CFLAGS="-O3 -mips64r6 -mabi=64 -mtune=i6400 -mmsa -mfp64 \
-  -msched-weight -mload-store-pairs -fPIE"
-MIPS_LDFLAGS="-mips64r6 -mabi=64 -mmsa -mfp64 -pie"
-
-./configure --host=${HOST} --build=`config.guess` \
-  CC="${HOST}-gcc -EL" \
-  CFLAGS="$MIPS_CFLAGS" \
-  LDFLAGS="$MIPS_LDFLAGS"
-make
-make install
-
-CMake:
-------
-With CMake, you can compile libwebp, cwebp, dwebp, gif2webp, img2webp, webpinfo
-and the JS bindings.
-
-Prerequisites:
-A compiler (e.g., gcc with autotools) and CMake.
-On a Debian-like system the following should install everything you need for a
-minimal build:
-$ sudo apt-get install build-essential cmake
-
-When building from git sources, you will need to run cmake to generate the
-makefiles.
-
-mkdir build && cd build && cmake ../
-make
-make install
-
-If you also want any of the executables, you will need to enable them through
-CMake, e.g.:
-
-cmake -DWEBP_BUILD_CWEBP=ON -DWEBP_BUILD_DWEBP=ON ../
-
-or through your favorite interface (like ccmake or cmake-qt-gui).
-
-Use option -DWEBP_UNICODE=ON for Unicode support on Windows (with chcp 65001).
-
-Finally, once installed, you can also use WebP in your CMake project by doing:
-
-find_package(WebP)
-
-which will define the CMake variables WebP_INCLUDE_DIRS and WebP_LIBRARIES.
-
-Gradle:
--------
-The support for Gradle is minimal: it only helps you compile libwebp, cwebp and
-dwebp and webpmux_example.
-
-Prerequisites:
-A compiler (e.g., gcc with autotools) and gradle.
-On a Debian-like system the following should install everything you need for a
-minimal build:
-$ sudo apt-get install build-essential gradle
-
-When building from git sources, you will need to run the Gradle wrapper with the
-appropriate target, e.g. :
-
-./gradlew buildAllExecutables
-
-SWIG bindings:
---------------
-
-To generate language bindings from swig/libwebp.swig at least swig-1.3
-(http://www.swig.org) is required.
-
-Currently the following functions are mapped:
-Decode:
-  WebPGetDecoderVersion
-  WebPGetInfo
-  WebPDecodeRGBA
-  WebPDecodeARGB
-  WebPDecodeBGRA
-  WebPDecodeBGR
-  WebPDecodeRGB
-
-Encode:
-  WebPGetEncoderVersion
-  WebPEncodeRGBA
-  WebPEncodeBGRA
-  WebPEncodeRGB
-  WebPEncodeBGR
-  WebPEncodeLosslessRGBA
-  WebPEncodeLosslessBGRA
-  WebPEncodeLosslessRGB
-  WebPEncodeLosslessBGR
-
-See swig/README for more detailed build instructions.
-
-Java bindings:
-
-To build the swig-generated JNI wrapper code at least JDK-1.5 (or equivalent)
-is necessary for enum support. The output is intended to be a shared object /
-DLL that can be loaded via System.loadLibrary("webp_jni").
-
-Python bindings:
-
-To build the swig-generated Python extension code at least Python 2.6 is
-required. Python < 2.6 may build with some minor changes to libwebp.swig or the
-generated code, but is untested.
-
-Encoding tool:
-==============
-
-The examples/ directory contains tools for encoding (cwebp) and
-decoding (dwebp) images.
-
-The easiest use should look like:
-  cwebp input.png -q 80 -o output.webp
-which will convert the input file to a WebP file using a quality factor of 80
-on a 0->100 scale (0 being the lowest quality, 100 being the best. Default
-value is 75).
-You might want to try the -lossless flag too, which will compress the source
-(in RGBA format) without any loss. The -q quality parameter will in this case
-control the amount of processing time spent trying to make the output file as
-small as possible.
-
-A longer list of options is available using the -longhelp command line flag:
-
-> cwebp -longhelp
-Usage:
- cwebp [-preset <...>] [options] in_file [-o out_file]
-
-If input size (-s) for an image is not specified, it is
-assumed to be a PNG, JPEG, TIFF or WebP file.
-Note: Animated PNG and WebP files are not supported.
-
-Options:
-  -h / -help ............. short help
-  -H / -longhelp ......... long help
-  -q <float> ............. quality factor (0:small..100:big), default=75
-  -alpha_q <int> ......... transparency-compression quality (0..100),
-                           default=100
-  -preset <string> ....... preset setting, one of:
-                            default, photo, picture,
-                            drawing, icon, text
-     -preset must come first, as it overwrites other parameters
-  -z <int> ............... activates lossless preset with given
-                           level in [0:fast, ..., 9:slowest]
-
-  -m <int> ............... compression method (0=fast, 6=slowest), default=4
-  -segments <int> ........ number of segments to use (1..4), default=4
-  -size <int> ............ target size (in bytes)
-  -psnr <float> .......... target PSNR (in dB. typically: 42)
-
-  -s <int> <int> ......... input size (width x height) for YUV
-  -sns <int> ............. spatial noise shaping (0:off, 100:max), default=50
-  -f <int> ............... filter strength (0=off..100), default=60
-  -sharpness <int> ....... filter sharpness (0:most .. 7:least sharp), default=0
-  -strong ................ use strong filter instead of simple (default)
-  -nostrong .............. use simple filter instead of strong
-  -sharp_yuv ............. use sharper (and slower) RGB->YUV conversion
-  -partition_limit <int> . limit quality to fit the 512k limit on
-                           the first partition (0=no degradation ... 100=full)
-  -pass <int> ............ analysis pass number (1..10)
-  -qrange <min> <max> .... specifies the permissible quality range
-                           (default: 0 100)
-  -crop <x> <y> <w> <h> .. crop picture with the given rectangle
-  -resize <w> <h> ........ resize picture (after any cropping)
-  -mt .................... use multi-threading if available
-  -low_memory ............ reduce memory usage (slower encoding)
-  -map <int> ............. print map of extra info
-  -print_psnr ............ prints averaged PSNR distortion
-  -print_ssim ............ prints averaged SSIM distortion
-  -print_lsim ............ prints local-similarity distortion
-  -d <file.pgm> .......... dump the compressed output (PGM file)
-  -alpha_method <int> .... transparency-compression method (0..1), default=1
-  -alpha_filter <string> . predictive filtering for alpha plane,
-                           one of: none, fast (default) or best
-  -exact ................. preserve RGB values in transparent area, default=off
-  -blend_alpha <hex> ..... blend colors against background color
-                           expressed as RGB values written in
-                           hexadecimal, e.g. 0xc0e0d0 for red=0xc0
-                           green=0xe0 and blue=0xd0
-  -noalpha ............... discard any transparency information
-  -lossless .............. encode image losslessly, default=off
-  -near_lossless <int> ... use near-lossless image
-                           preprocessing (0..100=off), default=100
-  -hint <string> ......... specify image characteristics hint,
-                           one of: photo, picture or graph
-
-  -metadata <string> ..... comma separated list of metadata to
-                           copy from the input to the output if present.
-                           Valid values: all, none (default), exif, icc, xmp
-
-  -short ................. condense printed message
-  -quiet ................. don't print anything
-  -version ............... print version number and exit
-  -noasm ................. disable all assembly optimizations
-  -v ..................... verbose, e.g. print encoding/decoding times
-  -progress .............. report encoding progress
-
-Experimental Options:
-  -jpeg_like ............. roughly match expected JPEG size
-  -af .................... auto-adjust filter strength
-  -pre <int> ............. pre-processing filter
-
-
-The main options you might want to try in order to further tune the
-visual quality are:
- -preset
- -sns
- -f
- -m
-
-Namely:
-  * 'preset' will set up a default encoding configuration targeting a
-     particular type of input. It should appear first in the list of options,
-     so that subsequent options can take effect on top of this preset.
-     Default value is 'default'.
-  * 'sns' will progressively turn on (when going from 0 to 100) some additional
-     visual optimizations (like: segmentation map re-enforcement). This option
-     will balance the bit allocation differently. It tries to take bits from the
-     "easy" parts of the picture and use them in the "difficult" ones instead.
-     Usually, raising the sns value (at fixed -q value) leads to larger files,
-     but with better quality.
-     Typical value is around '75'.
-  * 'f' option directly links to the filtering strength used by the codec's
-     in-loop processing. The higher the value, the smoother the
-     highly-compressed area will look. This is particularly useful when aiming
-     at very small files. Typical values are around 20-30. Note that using the
-     option -strong/-nostrong will change the type of filtering. Use "-f 0" to
-     turn filtering off.
-  * 'm' controls the trade-off between encoding speed and quality. Default is 4.
-     You can try -m 5 or -m 6 to explore more (time-consuming) encoding
-     possibilities. A lower value will result in faster encoding at the expense
-     of quality.
-
-Decoding tool:
-==============
-
-There is a decoding sample in examples/dwebp.c which will take
-a .webp file and decode it to a PNG image file (amongst other formats).
-This is simply to demonstrate the use of the API. You can verify the
-file test.webp decodes to exactly the same as test_ref.ppm by using:
-
- cd examples
- ./dwebp test.webp -ppm -o test.ppm
- diff test.ppm test_ref.ppm
-
-The full list of options is available using -h:
-
-> dwebp -h
-Usage: dwebp in_file [options] [-o out_file]
-
-Decodes the WebP image file to PNG format [Default].
-Note: Animated WebP files are not supported.
-
-Use following options to convert into alternate image formats:
-  -pam ......... save the raw RGBA samples as a color PAM
-  -ppm ......... save the raw RGB samples as a color PPM
-  -bmp ......... save as uncompressed BMP format
-  -tiff ........ save as uncompressed TIFF format
-  -pgm ......... save the raw YUV samples as a grayscale PGM
-                 file with IMC4 layout
-  -yuv ......... save the raw YUV samples in flat layout
-
- Other options are:
-  -version ..... print version number and exit
-  -nofancy ..... don't use the fancy YUV420 upscaler
-  -nofilter .... disable in-loop filtering
-  -nodither .... disable dithering
-  -dither <d> .. dithering strength (in 0..100)
-  -alpha_dither  use alpha-plane dithering if needed
-  -mt .......... use multi-threading
-  -crop <x> <y> <w> <h> ... crop output with the given rectangle
-  -resize <w> <h> ......... scale the output (*after* any cropping)
-  -flip ........ flip the output vertically
-  -alpha ....... only save the alpha plane
-  -incremental . use incremental decoding (useful for tests)
-  -h ........... this help message
-  -v ........... verbose (e.g. print encoding/decoding times)
-  -quiet ....... quiet mode, don't print anything
-  -noasm ....... disable all assembly optimizations
-
-WebP file analysis tool:
-========================
-
-'webpinfo' can be used to print out the chunk level structure and bitstream
-header information of WebP files. It can also check if the files are of valid
-WebP format.
-
-Usage: webpinfo [options] in_files
-Note: there could be multiple input files;
-      options must come before input files.
-Options:
-  -version ........... Print version number and exit.
-  -quiet ............. Do not show chunk parsing information.
-  -diag .............. Show parsing error diagnosis.
-  -summary ........... Show chunk stats summary.
-  -bitstream_info .... Parse bitstream header.
-
-Visualization tool:
-===================
-
-There's a little self-serve visualization tool called 'vwebp' under the
-examples/ directory. It uses OpenGL to open a simple drawing window and show
-a decoded WebP file. It's not yet integrated in the automake build system, but
-you can try to manually compile it using the recommendations below.
-
-Usage: vwebp in_file [options]
-
-Decodes the WebP image file and visualize it using OpenGL
-Options are:
-  -version ..... print version number and exit
-  -noicc ....... don't use the icc profile if present
-  -nofancy ..... don't use the fancy YUV420 upscaler
-  -nofilter .... disable in-loop filtering
-  -dither <int>  dithering strength (0..100), default=50
-  -noalphadither disable alpha plane dithering
-  -usebgcolor .. display background color
-  -mt .......... use multi-threading
-  -info ........ print info
-  -h ........... this help message
-
-Keyboard shortcuts:
-  'c' ................ toggle use of color profile
-  'b' ................ toggle background color display
-  'i' ................ overlay file information
-  'd' ................ disable blending & disposal (debug)
-  'q' / 'Q' / ESC .... quit
-
-Building:
----------
-
-Prerequisites:
-1) OpenGL & OpenGL Utility Toolkit (GLUT)
-  Linux:
-    $ sudo apt-get install freeglut3-dev mesa-common-dev
-  Mac + Xcode:
-    - These libraries should be available in the OpenGL / GLUT frameworks.
-  Windows:
-    http://freeglut.sourceforge.net/index.php#download
-
-2) (Optional) qcms (Quick Color Management System)
-  i. Download qcms from Mozilla / Chromium:
-    https://hg.mozilla.org/mozilla-central/file/0e7639e3bdfb/gfx/qcms
-    https://source.chromium.org/chromium/chromium/src/+/main:third_party/qcms/;drc=d4a2f8e1ed461d8fc05ed88d1ae2dc94c9773825
-  ii. Build and archive the source files as libqcms.a / qcms.lib
-  iii. Update makefile.unix / Makefile.vc
-    a) Define WEBP_HAVE_QCMS
-    b) Update include / library paths to reference the qcms directory.
-
-Build using makefile.unix / Makefile.vc:
-$ make -f makefile.unix examples/vwebp
-> nmake /f Makefile.vc CFG=release-static \
-    ../obj/x64/release-static/bin/vwebp.exe
-
-Animation creation tool:
-========================
-The utility 'img2webp' can turn a sequence of input images (PNG, JPEG, ...)
-into an animated WebP file. It offers fine control over duration, encoding
-modes, etc.
-
-Usage:
-
-  img2webp [file_options] [[frame_options] frame_file]...
-
-File-level options (only used at the start of compression):
- -min_size ............ minimize size
- -loop <int> .......... loop count (default: 0, = infinite loop)
- -kmax <int> .......... maximum number of frame between key-frames
-                        (0=only keyframes)
- -kmin <int> .......... minimum number of frame between key-frames
-                        (0=disable key-frames altogether)
- -mixed ............... use mixed lossy/lossless automatic mode
- -v ................... verbose mode
- -h ................... this help
- -version ............. print version number and exit
-
-Per-frame options (only used for subsequent images input):
- -d <int> ............. frame duration in ms (default: 100)
- -lossless  ........... use lossless mode (default)
- -lossy ... ........... use lossy mode
- -q <float> ........... quality
- -m <int> ............. method to use
-
-example: img2webp -loop 2 in0.png -lossy in1.jpg
-                  -d 80 in2.tiff -o out.webp
-
-Note: if a single file name is passed as the argument, the arguments will be
-tokenized from this file. The file name must not start with the character '-'.
-
-Animated GIF conversion:
-========================
-Animated GIF files can be converted to WebP files with animation using the
-gif2webp utility available under examples/. The files can then be viewed using
-vwebp.
-
-Usage:
- gif2webp [options] gif_file -o webp_file
-Options:
-  -h / -help ............. this help
-  -lossy ................. encode image using lossy compression
-  -mixed ................. for each frame in the image, pick lossy
-                           or lossless compression heuristically
-  -q <float> ............. quality factor (0:small..100:big)
-  -m <int> ............... compression method (0=fast, 6=slowest)
-  -min_size .............. minimize output size (default:off)
-                           lossless compression by default; can be
-                           combined with -q, -m, -lossy or -mixed
-                           options
-  -kmin <int> ............ min distance between key frames
-  -kmax <int> ............ max distance between key frames
-  -f <int> ............... filter strength (0=off..100)
-  -metadata <string> ..... comma separated list of metadata to
-                           copy from the input to the output if present
-                           Valid values: all, none, icc, xmp (default)
-  -loop_compatibility .... use compatibility mode for Chrome
-                           version prior to M62 (inclusive)
-  -mt .................... use multi-threading if available
-
-  -version ............... print version number and exit
-  -v ..................... verbose
-  -quiet ................. don't print anything
-
-Building:
----------
-With the libgif development files installed, gif2webp can be built using
-makefile.unix:
-$ make -f makefile.unix examples/gif2webp
-
-or using autoconf:
-$ ./configure --enable-everything
-$ make
-
-Comparison of animated images:
-==============================
-Test utility anim_diff under examples/ can be used to compare two animated
-images (each can be GIF or WebP).
-
-Usage: anim_diff <image1> <image2> [options]
-
-Options:
-  -dump_frames <folder> dump decoded frames in PAM format
-  -min_psnr <float> ... minimum per-frame PSNR
-  -raw_comparison ..... if this flag is not used, RGB is
-                        premultiplied before comparison
-  -max_diff <int> ..... maximum allowed difference per channel
-                        between corresponding pixels in subsequent
-                        frames
-  -h .................. this help
-  -version ............ print version number and exit
-
-Building:
----------
-With the libgif development files and a C++ compiler installed, anim_diff can
-be built using makefile.unix:
-$ make -f makefile.unix examples/anim_diff
-
-or using autoconf:
-$ ./configure --enable-everything
-$ make
-
-Encoding API:
-=============
-
-The main encoding functions are available in the header src/webp/encode.h
-The ready-to-use ones are:
-size_t WebPEncodeRGB(const uint8_t* rgb, int width, int height, int stride,
-                     float quality_factor, uint8_t** output);
-size_t WebPEncodeBGR(const uint8_t* bgr, int width, int height, int stride,
-                     float quality_factor, uint8_t** output);
-size_t WebPEncodeRGBA(const uint8_t* rgba, int width, int height, int stride,
-                      float quality_factor, uint8_t** output);
-size_t WebPEncodeBGRA(const uint8_t* bgra, int width, int height, int stride,
-                      float quality_factor, uint8_t** output);
-
-They will convert raw RGB samples to a WebP data. The only control supplied
-is the quality factor.
-
-There are some variants for using the lossless format:
-
-size_t WebPEncodeLosslessRGB(const uint8_t* rgb, int width, int height,
-                             int stride, uint8_t** output);
-size_t WebPEncodeLosslessBGR(const uint8_t* bgr, int width, int height,
-                             int stride, uint8_t** output);
-size_t WebPEncodeLosslessRGBA(const uint8_t* rgba, int width, int height,
-                              int stride, uint8_t** output);
-size_t WebPEncodeLosslessBGRA(const uint8_t* bgra, int width, int height,
-                              int stride, uint8_t** output);
-
-Of course in this case, no quality factor is needed since the compression
-occurs without loss of the input values, at the expense of larger output sizes.
-
-Advanced encoding API:
-----------------------
-
-A more advanced API is based on the WebPConfig and WebPPicture structures.
-
-WebPConfig contains the encoding settings and is not tied to a particular
-picture.
-WebPPicture contains input data, on which some WebPConfig will be used for
-compression.
-The encoding flow looks like:
-
--------------------------------------- BEGIN PSEUDO EXAMPLE
-
-#include <webp/encode.h>
-
-  // Setup a config, starting form a preset and tuning some additional
-  // parameters
-  WebPConfig config;
-  if (!WebPConfigPreset(&config, WEBP_PRESET_PHOTO, quality_factor)) {
-    return 0;   // version error
-  }
-  // ... additional tuning
-  config.sns_strength = 90;
-  config.filter_sharpness = 6;
-  config_error = WebPValidateConfig(&config);  // not mandatory, but useful
-
-  // Setup the input data
-  WebPPicture pic;
-  if (!WebPPictureInit(&pic)) {
-    return 0;  // version error
-  }
-  pic.width = width;
-  pic.height = height;
-  // allocated picture of dimension width x height
-  if (!WebPPictureAlloc(&pic)) {
-    return 0;   // memory error
-  }
-  // at this point, 'pic' has been initialized as a container,
-  // and can receive the Y/U/V samples.
-  // Alternatively, one could use ready-made import functions like
-  // WebPPictureImportRGB(), which will take care of memory allocation.
-  // In any case, past this point, one will have to call
-  // WebPPictureFree(&pic) to reclaim memory.
-
-  // Set up a byte-output write method. WebPMemoryWriter, for instance.
-  WebPMemoryWriter wrt;
-  WebPMemoryWriterInit(&wrt);     // initialize 'wrt'
-
-  pic.writer = MyFileWriter;
-  pic.custom_ptr = my_opaque_structure_to_make_MyFileWriter_work;
-
-  // Compress!
-  int ok = WebPEncode(&config, &pic);   // ok = 0 => error occurred!
-  WebPPictureFree(&pic);  // must be called independently of the 'ok' result.
-
-  // output data should have been handled by the writer at that point.
-  // -> compressed data is the memory buffer described by wrt.mem / wrt.size
-
-  // deallocate the memory used by compressed data
-  WebPMemoryWriterClear(&wrt);
-
--------------------------------------- END PSEUDO EXAMPLE
-
-Decoding API:
-=============
-
-This is mainly just one function to call:
-
-#include "webp/decode.h"
-uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
-                       int* width, int* height);
-
-Please have a look at the file src/webp/decode.h for the details.
-There are variants for decoding in BGR/RGBA/ARGB/BGRA order, along with
-decoding to raw Y'CbCr samples. One can also decode the image directly into a
-pre-allocated buffer.
-
-To detect a WebP file and gather the picture's dimensions, the function:
-  int WebPGetInfo(const uint8_t* data, size_t data_size,
-                  int* width, int* height);
-is supplied. No decoding is involved when using it.
-
-Incremental decoding API:
-=========================
-
-In the case when data is being progressively transmitted, pictures can still
-be incrementally decoded using a slightly more complicated API. Decoder state
-is stored into an instance of the WebPIDecoder object. This object can be
-created with the purpose of decoding either RGB or Y'CbCr samples.
-For instance:
-
-  WebPDecBuffer buffer;
-  WebPInitDecBuffer(&buffer);
-  buffer.colorspace = MODE_BGR;
-  ...
-  WebPIDecoder* idec = WebPINewDecoder(&buffer);
-
-As data is made progressively available, this incremental-decoder object
-can be used to decode the picture further. There are two (mutually exclusive)
-ways to pass freshly arrived data:
-
-either by appending the fresh bytes:
-
-  WebPIAppend(idec, fresh_data, size_of_fresh_data);
-
-or by just mentioning the new size of the transmitted data:
-
-  WebPIUpdate(idec, buffer, size_of_transmitted_buffer);
-
-Note that 'buffer' can be modified between each call to WebPIUpdate, in
-particular when the buffer is resized to accommodate larger data.
-
-These functions will return the decoding status: either VP8_STATUS_SUSPENDED if
-decoding is not finished yet or VP8_STATUS_OK when decoding is done. Any other
-status is an error condition.
-
-The 'idec' object must always be released (even upon an error condition) by
-calling: WebPDelete(idec).
-
-To retrieve partially decoded picture samples, one must use the corresponding
-method: WebPIDecGetRGB or WebPIDecGetYUVA.
-It will return the last displayable pixel row.
-
-Lastly, note that decoding can also be performed into a pre-allocated pixel
-buffer. This buffer must be passed when creating a WebPIDecoder, calling
-WebPINewRGB() or WebPINewYUVA().
-
-Please have a look at the src/webp/decode.h header for further details.
-
-Advanced Decoding API:
-======================
-
-WebP decoding supports an advanced API which provides on-the-fly cropping and
-rescaling, something of great usefulness on memory-constrained environments like
-mobile phones. Basically, the memory usage will scale with the output's size,
-not the input's, when one only needs a quick preview or a zoomed in portion of
-an otherwise too-large picture. Some CPU can be saved too, incidentally.
-
--------------------------------------- BEGIN PSEUDO EXAMPLE
-     // A) Init a configuration object
-     WebPDecoderConfig config;
-     CHECK(WebPInitDecoderConfig(&config));
-
-     // B) optional: retrieve the bitstream's features.
-     CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK);
-
-     // C) Adjust 'config' options, if needed
-     config.options.no_fancy_upsampling = 1;
-     config.options.use_scaling = 1;
-     config.options.scaled_width = scaledWidth();
-     config.options.scaled_height = scaledHeight();
-     // etc.
-
-     // D) Specify 'config' output options for specifying output colorspace.
-     // Optionally the external image decode buffer can also be specified.
-     config.output.colorspace = MODE_BGRA;
-     // Optionally, the config.output can be pointed to an external buffer as
-     // well for decoding the image. This externally supplied memory buffer
-     // should be big enough to store the decoded picture.
-     config.output.u.RGBA.rgba = (uint8_t*) memory_buffer;
-     config.output.u.RGBA.stride = scanline_stride;
-     config.output.u.RGBA.size = total_size_of_the_memory_buffer;
-     config.output.is_external_memory = 1;
-
-     // E) Decode the WebP image. There are two variants w.r.t decoding image.
-     // The first one (E.1) decodes the full image and the second one (E.2) is
-     // used to incrementally decode the image using small input buffers.
-     // Any one of these steps can be used to decode the WebP image.
-
-     // E.1) Decode full image.
-     CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK);
-
-     // E.2) Decode image incrementally.
-     WebPIDecoder* const idec = WebPIDecode(NULL, NULL, &config);
-     CHECK(idec != NULL);
-     while (bytes_remaining > 0) {
-       VP8StatusCode status = WebPIAppend(idec, input, bytes_read);
-       if (status == VP8_STATUS_OK || status == VP8_STATUS_SUSPENDED) {
-         bytes_remaining -= bytes_read;
-       } else {
-         break;
-       }
-     }
-     WebPIDelete(idec);
-
-     // F) Decoded image is now in config.output (and config.output.u.RGBA).
-     // It can be saved, displayed or otherwise processed.
-
-     // G) Reclaim memory allocated in config's object. It's safe to call
-     // this function even if the memory is external and wasn't allocated
-     // by WebPDecode().
-     WebPFreeDecBuffer(&config.output);
-
--------------------------------------- END PSEUDO EXAMPLE
-
-Bugs:
-=====
-
-Please report all bugs to the issue tracker:
-    https://bugs.chromium.org/p/webp
-Patches welcome! See this page to get started:
-    https://www.webmproject.org/code/contribute/submitting-patches/
-
-Discuss:
-========
-
-Email: webp-discuss@webmproject.org
-Web: https://groups.google.com/a/webmproject.org/group/webp-discuss

README.md

@@ -0,0 +1,54 @@
+# WebP Codec
+
+```
+      __   __  ____  ____  ____
+     /  \\/  \/  _ \/  _ )/  _ \
+     \       /   __/  _  \   __/
+      \__\__/\____/\_____/__/ ____  ___
+            / _/ /    \    \ /  _ \/ _/
+           /  \_/   / /   \ \   __/  \__
+           \____/____/\_____/_____/____/v1.4.0
+```
+
+WebP codec is a library to encode and decode images in WebP format. This package
+contains the library that can be used in other programs to add WebP support, as
+well as the command line tools 'cwebp' and 'dwebp' to compress and decompress
+images respectively.
+
+See https://developers.google.com/speed/webp for details on the image format.
+
+The latest source tree is available at
+https://chromium.googlesource.com/webm/libwebp
+
+It is released under the same license as the WebM project. See
+https://www.webmproject.org/license/software/ or the "COPYING" file for details.
+An additional intellectual property rights grant can be found in the file
+PATENTS.
+
+## Building
+
+See the [building documentation](doc/building.md).
+
+## Encoding and Decoding Tools
+
+The examples/ directory contains tools to encode and decode images and
+animations, view information about WebP images, and more. See the
+[tools documentation](doc/tools.md).
+
+## APIs
+
+See the [APIs documentation](doc/api.md), and API usage examples in the
+`examples/` directory.
+
+## Bugs
+
+Please report all bugs to the [issue tracker](https://issues.webmproject.org).
+For security reports, select 'Security report' from the Template dropdown.
+
+Patches welcome! See [how to contribute](CONTRIBUTING.md).
+
+## Discuss
+
+Email: webp-discuss@webmproject.org
+
+Web: https://groups.google.com/a/webmproject.org/group/webp-discuss

README.mux

@@ -1,258 +0,0 @@
-          __   __  ____  ____  ____  __ __  _     __ __
-         /  \\/  \/  _ \/  _ \/  _ \/  \  \/ \___/_ / _\
-         \       /   __/  _  \   __/      /  /  (_/  /__
-          \__\__/\_____/_____/__/  \__//_/\_____/__/___/v1.2.2
-
-
-Description:
-============
-
-WebPMux: set of two libraries 'Mux' and 'Demux' for creation, extraction and
-manipulation of an extended format WebP file, which can have features like
-color profile, metadata and animation. Reference command-line tools 'webpmux'
-and 'vwebp' as well as the WebP container specification
-'doc/webp-container-spec.txt' are also provided in this package.
-
-WebP Mux tool:
-==============
-
-The examples/ directory contains a tool (webpmux) for manipulating WebP
-files. The webpmux tool can be used to create an extended format WebP file and
-also to extract or strip relevant data from such a file.
-
-A list of options is available using the -help command line flag:
-
-> webpmux -help
-Usage: webpmux -get GET_OPTIONS INPUT -o OUTPUT
-       webpmux -set SET_OPTIONS INPUT -o OUTPUT
-       webpmux -duration DURATION_OPTIONS [-duration ...]
-               INPUT -o OUTPUT
-       webpmux -strip STRIP_OPTIONS INPUT -o OUTPUT
-       webpmux -frame FRAME_OPTIONS [-frame...] [-loop LOOP_COUNT]
-               [-bgcolor BACKGROUND_COLOR] -o OUTPUT
-       webpmux -info INPUT
-       webpmux [-h|-help]
-       webpmux -version
-       webpmux argument_file_name
-
-GET_OPTIONS:
- Extract relevant data:
-   icc       get ICC profile
-   exif      get EXIF metadata
-   xmp       get XMP metadata
-   frame n   get nth frame
-
-SET_OPTIONS:
- Set color profile/metadata/parameters:
-   loop LOOP_COUNT            set the loop count
-   bgcolor BACKGROUND_COLOR   set the animation background color
-   icc  file.icc              set ICC profile
-   exif file.exif             set EXIF metadata
-   xmp  file.xmp              set XMP metadata
-   where:    'file.icc' contains the ICC profile to be set,
-             'file.exif' contains the EXIF metadata to be set
-             'file.xmp' contains the XMP metadata to be set
-
-DURATION_OPTIONS:
- Set duration of selected frames:
-   duration            set duration for each frames
-   duration,frame      set duration of a particular frame
-   duration,start,end  set duration of frames in the
-                        interval [start,end])
-   where: 'duration' is the duration in milliseconds
-          'start' is the start frame index
-          'end' is the inclusive end frame index
-           The special 'end' value '0' means: last frame.
-
-STRIP_OPTIONS:
- Strip color profile/metadata:
-   icc       strip ICC profile
-   exif      strip EXIF metadata
-   xmp       strip XMP metadata
-
-FRAME_OPTIONS(i):
- Create animation:
-   file_i +di+[xi+yi[+mi[bi]]]
-   where:    'file_i' is the i'th animation frame (WebP format),
-             'di' is the pause duration before next frame,
-             'xi','yi' specify the image offset for this frame,
-             'mi' is the dispose method for this frame (0 or 1),
-             'bi' is the blending method for this frame (+b or -b)
-
-LOOP_COUNT:
- Number of times to repeat the animation.
- Valid range is 0 to 65535 [Default: 0 (infinite)].
-
-BACKGROUND_COLOR:
- Background color of the canvas.
-  A,R,G,B
-  where:    'A', 'R', 'G' and 'B' are integers in the range 0 to 255 specifying
-            the Alpha, Red, Green and Blue component values respectively
-            [Default: 255,255,255,255]
-
-INPUT & OUTPUT are in WebP format.
-
-Note: The nature of EXIF, XMP and ICC data is not checked and is assumed to be
-valid.
-
-Note: if a single file name is passed as the argument, the arguments will be
-tokenized from this file. The file name must not start with the character '-'.
-
-Visualization tool:
-===================
-
-The examples/ directory also contains a tool (vwebp) for viewing WebP files.
-It decodes the image and visualizes it using OpenGL. See the libwebp README
-for details on building and running this program.
-
-Mux API:
-========
-The Mux API contains methods for adding data to and reading data from WebP
-files. This API currently supports XMP/EXIF metadata, ICC profile and animation.
-Other features may be added in subsequent releases.
-
-Example#1 (pseudo code): Creating a WebPMux object with image data, color
-profile and XMP metadata.
-
-  int copy_data = 0;
-  WebPMux* mux = WebPMuxNew();
-  // ... (Prepare image data).
-  WebPMuxSetImage(mux, &image, copy_data);
-  // ... (Prepare ICC profile data).
-  WebPMuxSetChunk(mux, "ICCP", &icc_profile, copy_data);
-  // ... (Prepare XMP metadata).
-  WebPMuxSetChunk(mux, "XMP ", &xmp, copy_data);
-  // Get data from mux in WebP RIFF format.
-  WebPMuxAssemble(mux, &output_data);
-  WebPMuxDelete(mux);
-  // ... (Consume output_data; e.g. write output_data.bytes to file).
-  WebPDataClear(&output_data);
-
-
-Example#2 (pseudo code): Get image and color profile data from a WebP file.
-
-  int copy_data = 0;
-  // ... (Read data from file).
-  WebPMux* mux = WebPMuxCreate(&data, copy_data);
-  WebPMuxGetFrame(mux, 1, &image);
-  // ... (Consume image; e.g. call WebPDecode() to decode the data).
-  WebPMuxGetChunk(mux, "ICCP", &icc_profile);
-  // ... (Consume icc_profile).
-  WebPMuxDelete(mux);
-  free(data);
-
-
-For a detailed Mux API reference, please refer to the header file
-(src/webp/mux.h).
-
-Demux API:
-==========
-The Demux API enables extraction of images and extended format data from
-WebP files. This API currently supports reading of XMP/EXIF metadata, ICC
-profile and animated images. Other features may be added in subsequent
-releases.
-
-Code example: Demuxing WebP data to extract all the frames, ICC profile
-and EXIF/XMP metadata.
-
-  WebPDemuxer* demux = WebPDemux(&webp_data);
-  uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
-  uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
-  // ... (Get information about the features present in the WebP file).
-  uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
-
-  // ... (Iterate over all frames).
-  WebPIterator iter;
-  if (WebPDemuxGetFrame(demux, 1, &iter)) {
-    do {
-      // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(),
-      // ... and get other frame properties like width, height, offsets etc.
-      // ... see 'struct WebPIterator' below for more info).
-    } while (WebPDemuxNextFrame(&iter));
-    WebPDemuxReleaseIterator(&iter);
-  }
-
-  // ... (Extract metadata).
-  WebPChunkIterator chunk_iter;
-  if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter);
-  // ... (Consume the ICC profile in 'chunk_iter.chunk').
-  WebPDemuxReleaseChunkIterator(&chunk_iter);
-  if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter);
-  // ... (Consume the EXIF metadata in 'chunk_iter.chunk').
-  WebPDemuxReleaseChunkIterator(&chunk_iter);
-  if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter);
-  // ... (Consume the XMP metadata in 'chunk_iter.chunk').
-  WebPDemuxReleaseChunkIterator(&chunk_iter);
-  WebPDemuxDelete(demux);
-
-
-For a detailed Demux API reference, please refer to the header file
-(src/webp/demux.h).
-
-AnimEncoder API:
-================
-The AnimEncoder API can be used to create animated WebP images.
-
-Code example:
-
-  WebPAnimEncoderOptions enc_options;
-  WebPAnimEncoderOptionsInit(&enc_options);
-  // ... (Tune 'enc_options' as needed).
-  WebPAnimEncoder* enc = WebPAnimEncoderNew(width, height, &enc_options);
-  while(<there are more frames>) {
-    WebPConfig config;
-    WebPConfigInit(&config);
-    // ... (Tune 'config' as needed).
-    WebPAnimEncoderAdd(enc, frame, duration, &config);
-  }
-  WebPAnimEncoderAssemble(enc, webp_data);
-  WebPAnimEncoderDelete(enc);
-  // ... (Write the 'webp_data' to a file, or re-mux it further).
-
-
-For a detailed AnimEncoder API reference, please refer to the header file
-(src/webp/mux.h).
-
-AnimDecoder API:
-================
-This AnimDecoder API allows decoding (possibly) animated WebP images.
-
-Code Example:
-
-  WebPAnimDecoderOptions dec_options;
-  WebPAnimDecoderOptionsInit(&dec_options);
-  // Tune 'dec_options' as needed.
-  WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options);
-  WebPAnimInfo anim_info;
-  WebPAnimDecoderGetInfo(dec, &anim_info);
-  for (uint32_t i = 0; i < anim_info.loop_count; ++i) {
-    while (WebPAnimDecoderHasMoreFrames(dec)) {
-      uint8_t* buf;
-      int timestamp;
-      WebPAnimDecoderGetNext(dec, &buf, &timestamp);
-      // ... (Render 'buf' based on 'timestamp').
-      // ... (Do NOT free 'buf', as it is owned by 'dec').
-    }
-    WebPAnimDecoderReset(dec);
-  }
-  const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec);
-  // ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data).
-  WebPAnimDecoderDelete(dec);
-
-For a detailed AnimDecoder API reference, please refer to the header file
-(src/webp/demux.h).
-
-
-Bugs:
-=====
-
-Please report all bugs to the issue tracker:
-    https://bugs.chromium.org/p/webp
-Patches welcome! See this page to get started:
-    https://www.webmproject.org/code/contribute/submitting-patches/
-
-Discuss:
-========
-
-Email: webp-discuss@webmproject.org
-Web: https://groups.google.com/a/webmproject.org/group/webp-discuss

README.webp_js

@@ -1,75 +0,0 @@
-     __   __ ____ ____ ____     __  ____
-    /  \\/  \  _ \  _ \  _ \   (__)/  __\
-    \       /  __/ _  \  __/   _)  \_   \
-     \__\__/_____/____/_/     /____/____/
-
-Description:
-============
-
-This file describes the compilation of libwebp into a JavaScript decoder
-using Emscripten and CMake.
-
- - install the Emscripten SDK following the procedure described at:
-   https://emscripten.org/docs/getting_started/downloads.html#installation-instructions-using-the-emsdk-recommended
-   After installation, you should have some global variable positioned to the
-   location of the SDK. In particular, $EMSDK should point to the
-   top-level directory containing Emscripten tools.
-
- - configure the project 'WEBP_JS' with CMake using:
-
- cd webp_js && \
- emcmake cmake -DWEBP_BUILD_WEBP_JS=ON \
-       ../
-
- - compile webp.js using 'emmake make'.
-
- - that's it! Upon completion, you should have the webp.js and
-   webp.wasm files generated.
-
-The callable JavaScript function is WebPToSDL(), which decodes a raw WebP
-bitstream into a canvas. See webp_js/index.html for a simple usage sample
-(see below for instructions).
-
-Demo HTML page:
-===============
-
-   The HTML page webp_js/index.html requires an HTTP server to serve the WebP
-   image example. It's easy to just use Python for that.
-
-cd webp_js && python -m SimpleHTTPServer 8080
-
-and then navigate to http://localhost:8080 in your favorite browser.
-
-
-Web-Assembly (WASM) version:
-============================
-
-  CMakeLists.txt is configured to build the WASM version when using
-  the option WEBP_BUILD_WEBP_JS=ON. The compilation step will assemble
-  the files 'webp_wasm.js', 'webp_wasm.wasm' in the webp_js/ directory.
-  See webp_js/index_wasm.html for a simple demo page using the WASM version
-  of the library.
-
-  You will need a fairly recent version of Emscripten (at least 2.0.18,
-  latest-upstream is recommended) and of your WASM-enabled browser to run this
-  version.
-
-Caveat:
-=======
-
-  - First decoding using the library is usually slower, due to just-in-time
-    compilation.
-
-  - Some versions of llvm produce the following compile error when SSE2 is
-    enabled.
-
-"Unsupported:   %516 = bitcast <8 x i16> %481 to i128
- LLVM ERROR: BitCast Instruction not yet supported for integer types larger than 64 bits"
-
-    The corresponding Emscripten bug is at:
-    https://github.com/kripken/emscripten/issues/3788
-
-    Therefore, SSE2 optimization is currently disabled in CMakeLists.txt.
-
-  - If WEBP_ENABLE_SIMD is set to 1 the JavaScript version (webp.js) will be
-    disabled as wasm2js does not support SIMD.

build.gradle

@@ -105,6 +105,14 @@ model {
       sources {
         c {
           source {
+            srcDir "sharpyuv"
+            include "sharpyuv.c"
+            include "sharpyuv_cpu.c"
+            include "sharpyuv_csp.c"
+            include "sharpyuv_dsp.c"
+            include "sharpyuv_gamma.c"
+            include "sharpyuv_neon.c"
+            include "sharpyuv_sse2.c"
             srcDir "src/dec"
             include "alpha_dec.c"
             include "buffer_dec.c"
@@ -165,6 +173,7 @@ model {
             include "color_cache_utils.c"
             include "filters_utils.c"
             include "huffman_utils.c"
+            include "palette.c"
             include "quant_levels_dec_utils.c"
             include "random_utils.c"
             include "rescaler_utils.c"

cmake/WebPConfig.cmake.in

@@ -3,9 +3,17 @@ set(WEBP_VERSION ${WebP_VERSION})
 
 @PACKAGE_INIT@
 
-include ("${CMAKE_CURRENT_LIST_DIR}/@PROJECT_NAME@Targets.cmake")
+if(@WEBP_USE_THREAD@)
+  include(CMakeFindDependencyMacro)
+  find_dependency(Threads REQUIRED)
+endif()
 
-set(WebP_INCLUDE_DIRS "@CMAKE_INSTALL_FULL_INCLUDEDIR@")
-set(WEBP_INCLUDE_DIRS ${WebP_INCLUDE_DIRS})
+include("${CMAKE_CURRENT_LIST_DIR}/@PROJECT_NAME@Targets.cmake")
+
+set_and_check(WebP_INCLUDE_DIR "@PACKAGE_CMAKE_INSTALL_INCLUDEDIR@")
+set(WebP_INCLUDE_DIRS ${WebP_INCLUDE_DIR})
+set(WEBP_INCLUDE_DIRS ${WebP_INCLUDE_DIR})
 set(WebP_LIBRARIES "@INSTALLED_LIBRARIES@")
 set(WEBP_LIBRARIES "${WebP_LIBRARIES}")
+
+check_required_components(WebP)

cmake/config.h.in

@@ -16,48 +16,18 @@
 /* Define to 1 if you have the <cpu-features.h> header file. */
 #cmakedefine HAVE_CPU_FEATURES_H 1
 
-/* Define to 1 if you have the <dlfcn.h> header file. */
-#cmakedefine HAVE_DLFCN_H 1
-
 /* Define to 1 if you have the <GLUT/glut.h> header file. */
 #cmakedefine HAVE_GLUT_GLUT_H 1
 
 /* Define to 1 if you have the <GL/glut.h> header file. */
 #cmakedefine HAVE_GL_GLUT_H 1
 
-/* Define to 1 if you have the <inttypes.h> header file. */
-#cmakedefine HAVE_INTTYPES_H 1
-
-/* Define to 1 if you have the <memory.h> header file. */
-#cmakedefine HAVE_MEMORY_H 1
-
 /* Define to 1 if you have the <OpenGL/glut.h> header file. */
 #cmakedefine HAVE_OPENGL_GLUT_H 1
 
-/* Have PTHREAD_PRIO_INHERIT. */
-#cmakedefine HAVE_PTHREAD_PRIO_INHERIT @HAVE_PTHREAD_PRIO_INHERIT@
-
 /* Define to 1 if you have the <shlwapi.h> header file. */
 #cmakedefine HAVE_SHLWAPI_H 1
 
-/* Define to 1 if you have the <stdint.h> header file. */
-#cmakedefine HAVE_STDINT_H 1
-
-/* Define to 1 if you have the <stdlib.h> header file. */
-#cmakedefine HAVE_STDLIB_H 1
-
-/* Define to 1 if you have the <strings.h> header file. */
-#cmakedefine HAVE_STRINGS_H 1
-
-/* Define to 1 if you have the <string.h> header file. */
-#cmakedefine HAVE_STRING_H 1
-
-/* Define to 1 if you have the <sys/stat.h> header file. */
-#cmakedefine HAVE_SYS_STAT_H 1
-
-/* Define to 1 if you have the <sys/types.h> header file. */
-#cmakedefine HAVE_SYS_TYPES_H 1
-
 /* Define to 1 if you have the <unistd.h> header file. */
 #cmakedefine HAVE_UNISTD_H 1
 
@@ -93,9 +63,6 @@
 /* Define to the version of this package. */
 #cmakedefine PACKAGE_VERSION "@PACKAGE_VERSION@"
 
-/* Define to 1 if you have the ANSI C header files. */
-#cmakedefine STDC_HEADERS 1
-
 /* Version number of package */
 #cmakedefine VERSION "@VERSION@"
 

cmake/cpu.cmake

@@ -18,7 +18,8 @@ function(webp_check_compiler_flag WEBP_SIMD_FLAG ENABLE_SIMD)
   unset(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG} CACHE)
   cmake_push_check_state()
   set(CMAKE_REQUIRED_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR})
-  check_c_source_compiles("
+  check_c_source_compiles(
+    "
       #include \"${CMAKE_CURRENT_LIST_DIR}/../src/dsp/dsp.h\"
       int main(void) {
         #if !defined(WEBP_USE_${WEBP_SIMD_FLAG})
@@ -26,7 +27,8 @@ function(webp_check_compiler_flag WEBP_SIMD_FLAG ENABLE_SIMD)
         #endif
         return 0;
       }
-    " WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
+    "
+    WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
   cmake_pop_check_state()
   if(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
     set(WEBP_HAVE_${WEBP_SIMD_FLAG} 1 PARENT_SCOPE)
@@ -52,17 +54,14 @@ if(MSVC AND CMAKE_C_COMPILER_ID STREQUAL "MSVC")
   endif()
   set(SIMD_DISABLE_FLAGS)
 else()
-  set(SIMD_ENABLE_FLAGS
-      "-msse4.1;-msse2;-mips32;-mdspr2;-mfpu=neon;-mmsa")
-  set(SIMD_DISABLE_FLAGS
-      "-mno-sse4.1;-mno-sse2;;-mno-dspr2;;-mno-msa")
+  set(SIMD_ENABLE_FLAGS "-msse4.1;-msse2;-mips32;-mdspr2;-mfpu=neon;-mmsa")
+  set(SIMD_DISABLE_FLAGS "-mno-sse4.1;-mno-sse2;;-mno-dspr2;;-mno-msa")
 endif()
 
-set(WEBP_SIMD_FILES_TO_NOT_INCLUDE)
 set(WEBP_SIMD_FILES_TO_INCLUDE)
 set(WEBP_SIMD_FLAGS_TO_INCLUDE)
 
-if(${ANDROID})
+if(ANDROID AND ANDROID_ABI)
   if(${ANDROID_ABI} STREQUAL "armeabi-v7a")
     # This is because Android studio uses the configuration "-march=armv7-a
     # -mfloat-abi=softfp -mfpu=vfpv3-d16" that does not trigger neon
@@ -75,8 +74,8 @@ list(LENGTH WEBP_SIMD_FLAGS WEBP_SIMD_FLAGS_LENGTH)
 math(EXPR WEBP_SIMD_FLAGS_RANGE "${WEBP_SIMD_FLAGS_LENGTH} - 1")
 
 foreach(I_SIMD RANGE ${WEBP_SIMD_FLAGS_RANGE})
-  # With Emscripten 2.0.9 -msimd128 -mfpu=neon will enable NEON, but the
-  # source will fail to compile.
+  # With Emscripten 2.0.9 -msimd128 -mfpu=neon will enable NEON, but the source
+  # will fail to compile.
   if(EMSCRIPTEN AND ${I_SIMD} GREATER_EQUAL 2)
     break()
   endif()
@@ -107,8 +106,9 @@ foreach(I_SIMD RANGE ${WEBP_SIMD_FLAGS_RANGE})
   endif()
   # Check which files we should include or not.
   list(GET WEBP_SIMD_FILE_EXTENSIONS ${I_SIMD} WEBP_SIMD_FILE_EXTENSION)
-  file(GLOB SIMD_FILES "${CMAKE_CURRENT_LIST_DIR}/../"
-            "src/dsp/*${WEBP_SIMD_FILE_EXTENSION}")
+  file(GLOB SIMD_FILES
+       "${CMAKE_CURRENT_LIST_DIR}/../sharpyuv/*${WEBP_SIMD_FILE_EXTENSION}"
+       "${CMAKE_CURRENT_LIST_DIR}/../src/dsp/*${WEBP_SIMD_FILE_EXTENSION}")
   if(WEBP_HAVE_${WEBP_SIMD_FLAG})
     # Memorize the file and flags.
     foreach(FILE ${SIMD_FILES})
@@ -142,11 +142,9 @@ foreach(I_SIMD RANGE ${WEBP_SIMD_FLAGS_RANGE})
             set(COMMON_PATTERNS)
           endif()
           set(CMAKE_REQUIRED_DEFINITIONS ${SIMD_COMPILE_FLAG})
-          check_c_source_compiles("int main(void) {return 0;}"
-                                  FLAG_${SIMD_COMPILE_FLAG}
-                                  FAIL_REGEX
-                                  "warning: argument unused during compilation:"
-                                  ${COMMON_PATTERNS})
+          check_c_source_compiles(
+            "int main(void) {return 0;}" FLAG_${SIMD_COMPILE_FLAG} FAIL_REGEX
+            "warning: argument unused during compilation:" ${COMMON_PATTERNS})
           if(NOT FLAG_${SIMD_COMPILE_FLAG})
             unset(HAS_COMPILE_FLAG)
             unset(HAS_COMPILE_FLAG CACHE)

cmake/deps.cmake

@@ -10,24 +10,30 @@
 
 # Check for compiler options.
 include(CheckCSourceCompiles)
-check_c_source_compiles("
+check_c_source_compiles(
+  "
     int main(void) {
       (void)__builtin_bswap16(0);
       return 0;
     }
-  " HAVE_BUILTIN_BSWAP16)
-check_c_source_compiles("
+  "
+  HAVE_BUILTIN_BSWAP16)
+check_c_source_compiles(
+  "
     int main(void) {
       (void)__builtin_bswap32(0);
       return 0;
     }
-  " HAVE_BUILTIN_BSWAP32)
-check_c_source_compiles("
+  "
+  HAVE_BUILTIN_BSWAP32)
+check_c_source_compiles(
+  "
     int main(void) {
       (void)__builtin_bswap64(0);
       return 0;
     }
-  " HAVE_BUILTIN_BSWAP64)
+  "
+  HAVE_BUILTIN_BSWAP64)
 
 # Check for libraries.
 if(WEBP_USE_THREAD)
@@ -37,15 +43,7 @@ if(WEBP_USE_THREAD)
     if(CMAKE_USE_PTHREADS_INIT AND NOT CMAKE_SYSTEM_NAME STREQUAL "QNX")
       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")
     endif()
-    check_c_source_compiles("
-        #include <pthread.h>
-        int main (void) {
-          int attr = PTHREAD_PRIO_INHERIT;
-          return attr;
-        }
-      " FLAG_HAVE_PTHREAD_PRIO_INHERIT)
-    set(HAVE_PTHREAD_PRIO_INHERIT ${FLAG_HAVE_PTHREAD_PRIO_INHERIT})
-    list(APPEND WEBP_DEP_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
+    list(APPEND WEBP_DEP_LIBRARIES Threads::Threads)
   endif()
   set(WEBP_USE_THREAD ${Threads_FOUND})
 endif()
@@ -59,89 +57,88 @@ set(WEBP_HAVE_GL ${OPENGL_FOUND})
 
 # Check if we need to link to the C math library. We do not look for it as it is
 # not found when cross-compiling, while it is here.
-check_c_source_compiles("
+check_c_source_compiles(
+  "
     #include <math.h>
     int main(int argc, char** argv) {
       return (int)pow(argc, 2.5);
     }
-  " HAVE_MATH_LIBRARY)
+  "
+  HAVE_MATH_LIBRARY)
 if(NOT HAVE_MATH_LIBRARY)
   message(STATUS "Adding -lm flag.")
+  list(APPEND SHARPYUV_DEP_LIBRARIES m)
   list(APPEND WEBP_DEP_LIBRARIES m)
 endif()
 
 # Find the standard image libraries.
 set(WEBP_DEP_IMG_LIBRARIES)
 set(WEBP_DEP_IMG_INCLUDE_DIRS)
-foreach(I_LIB PNG JPEG TIFF)
-  find_package(${I_LIB})
-  set(WEBP_HAVE_${I_LIB} ${${I_LIB}_FOUND})
-  if(${I_LIB}_FOUND)
-    list(APPEND WEBP_DEP_IMG_LIBRARIES ${${I_LIB}_LIBRARIES})
-    list(APPEND WEBP_DEP_IMG_INCLUDE_DIRS ${${I_LIB}_INCLUDE_DIR}
-                ${${I_LIB}_INCLUDE_DIRS})
+if(WEBP_FIND_IMG_LIBS)
+  foreach(I_LIB PNG JPEG TIFF)
+    # Disable tiff when compiling in static mode as it is failing on Ubuntu.
+    if(WEBP_LINK_STATIC AND ${I_LIB} STREQUAL "TIFF")
+      message(STATUS "TIFF is disabled when statically linking.")
+      continue()
+    endif()
+    find_package(${I_LIB})
+    set(WEBP_HAVE_${I_LIB} ${${I_LIB}_FOUND})
+    if(${I_LIB}_FOUND)
+      list(APPEND WEBP_DEP_IMG_LIBRARIES ${${I_LIB}_LIBRARIES})
+      list(APPEND WEBP_DEP_IMG_INCLUDE_DIRS ${${I_LIB}_INCLUDE_DIR}
+           ${${I_LIB}_INCLUDE_DIRS})
+    endif()
+  endforeach()
+  if(WEBP_DEP_IMG_INCLUDE_DIRS)
+    list(REMOVE_DUPLICATES WEBP_DEP_IMG_INCLUDE_DIRS)
   endif()
-endforeach()
-if(WEBP_DEP_IMG_INCLUDE_DIRS)
-  list(REMOVE_DUPLICATES WEBP_DEP_IMG_INCLUDE_DIRS)
-endif()
 
-# GIF detection, gifdec isn't part of the imageio lib.
-include(CMakePushCheckState)
-set(WEBP_DEP_GIF_LIBRARIES)
-set(WEBP_DEP_GIF_INCLUDE_DIRS)
-find_package(GIF)
-set(WEBP_HAVE_GIF ${GIF_FOUND})
-if(GIF_FOUND)
-  # GIF find_package only locates the header and library, it doesn't fail
-  # compile tests when detecting the version, but falls back to 3 (as of at
-  # least cmake 3.7.2). Make sure the library links to avoid incorrect detection
-  # when cross compiling.
-  cmake_push_check_state()
-  set(CMAKE_REQUIRED_LIBRARIES ${GIF_LIBRARIES})
-  set(CMAKE_REQUIRED_INCLUDES ${GIF_INCLUDE_DIR})
-  check_c_source_compiles("
+  # GIF detection, gifdec isn't part of the imageio lib.
+  include(CMakePushCheckState)
+  set(WEBP_DEP_GIF_LIBRARIES)
+  set(WEBP_DEP_GIF_INCLUDE_DIRS)
+  find_package(GIF)
+  set(WEBP_HAVE_GIF ${GIF_FOUND})
+  if(GIF_FOUND)
+    # GIF find_package only locates the header and library, it doesn't fail
+    # compile tests when detecting the version, but falls back to 3 (as of at
+    # least cmake 3.7.2). Make sure the library links to avoid incorrect
+    # detection when cross compiling.
+    cmake_push_check_state()
+    set(CMAKE_REQUIRED_LIBRARIES ${GIF_LIBRARIES})
+    set(CMAKE_REQUIRED_INCLUDES ${GIF_INCLUDE_DIR})
+    check_c_source_compiles(
+      "
       #include <gif_lib.h>
       int main(void) {
         (void)DGifOpenFileHandle;
         return 0;
       }
-      " GIF_COMPILES)
-  cmake_pop_check_state()
-  if(GIF_COMPILES)
-    list(APPEND WEBP_DEP_GIF_LIBRARIES ${GIF_LIBRARIES})
-    list(APPEND WEBP_DEP_GIF_INCLUDE_DIRS ${GIF_INCLUDE_DIR})
-  else()
-    unset(GIF_FOUND)
+      "
+      GIF_COMPILES)
+    cmake_pop_check_state()
+    if(GIF_COMPILES)
+      list(APPEND WEBP_DEP_GIF_LIBRARIES ${GIF_LIBRARIES})
+      list(APPEND WEBP_DEP_GIF_INCLUDE_DIRS ${GIF_INCLUDE_DIR})
+    else()
+      unset(GIF_FOUND)
+    endif()
   endif()
 endif()
 
 # Check for specific headers.
 include(CheckIncludeFiles)
-check_include_files("stdlib.h;stdarg.h;string.h;float.h" STDC_HEADERS)
-check_include_files(dlfcn.h HAVE_DLFCN_H)
 check_include_files(GLUT/glut.h HAVE_GLUT_GLUT_H)
 check_include_files(GL/glut.h HAVE_GL_GLUT_H)
-check_include_files(inttypes.h HAVE_INTTYPES_H)
-check_include_files(memory.h HAVE_MEMORY_H)
 check_include_files(OpenGL/glut.h HAVE_OPENGL_GLUT_H)
 check_include_files(shlwapi.h HAVE_SHLWAPI_H)
-check_include_files(stdint.h HAVE_STDINT_H)
-check_include_files(stdlib.h HAVE_STDLIB_H)
-check_include_files(strings.h HAVE_STRINGS_H)
-check_include_files(string.h HAVE_STRING_H)
-check_include_files(sys/stat.h HAVE_SYS_STAT_H)
-check_include_files(sys/types.h HAVE_SYS_TYPES_H)
 check_include_files(unistd.h HAVE_UNISTD_H)
 check_include_files(wincodec.h HAVE_WINCODEC_H)
 check_include_files(windows.h HAVE_WINDOWS_H)
 
 # Windows specifics
 if(HAVE_WINCODEC_H)
-  list(APPEND WEBP_DEP_LIBRARIES
-              shlwapi
-              ole32
-              windowscodecs)
+  list(APPEND WEBP_DEP_LIBRARIES shlwapi ole32 windowscodecs)
 endif()
 
 # Check for SIMD extensions.
@@ -153,17 +150,12 @@ set(PACKAGE_NAME ${PROJECT_NAME})
 
 # Read from configure.ac.
 file(READ ${CMAKE_CURRENT_SOURCE_DIR}/configure.ac CONFIGURE_AC)
-string(REGEX MATCHALL
-             "\\[([0-9a-z\\.:/]*)\\]"
-             CONFIGURE_AC_PACKAGE_INFO
+string(REGEX MATCHALL "\\[([0-9a-z\\.:/]*)\\]" CONFIGURE_AC_PACKAGE_INFO
              ${CONFIGURE_AC})
 function(strip_bracket VAR)
   string(LENGTH ${${VAR}} TMP_LEN)
   math(EXPR TMP_LEN ${TMP_LEN}-2)
-  string(SUBSTRING ${${VAR}}
-                   1
-                   ${TMP_LEN}
-                   TMP_SUB)
+  string(SUBSTRING ${${VAR}} 1 ${TMP_LEN} TMP_SUB)
   set(${VAR} ${TMP_SUB} PARENT_SCOPE)
 endfunction()
 

configure.ac

@@ -1,5 +1,5 @@
-AC_INIT([libwebp], [1.2.2],
-        [https://bugs.chromium.org/p/webp],,
+AC_INIT([libwebp], [1.4.0],
+        [https://issues.webmproject.org],,
         [https://developers.google.com/speed/webp])
 AC_CANONICAL_HOST
 AC_PREREQ([2.60])
@@ -9,7 +9,8 @@ dnl === automake >= 1.12 requires this for 'unusual archivers' support.
 dnl === it must occur before LT_INIT (AC_PROG_LIBTOOL).
 m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
 
-AC_PROG_LIBTOOL
+dnl === AC_PROG_LIBTOOL is deprecated.
+m4_ifdef([LT_INIT], [LT_INIT], [AC_PROG_LIBTOOL])
 AC_PROG_SED
 AM_PROG_CC_C_O
 
@@ -27,7 +28,8 @@ AC_ARG_ENABLE([everything],
               AS_HELP_STRING([--enable-everything],
                              [Enable all optional targets. These can still be
                               disabled with --disable-target]),
-              [SET_IF_UNSET([enable_libwebpdecoder], [$enableval])
+              [SET_IF_UNSET([enable_libsharpyuv], [$enableval])
+               SET_IF_UNSET([enable_libwebpdecoder], [$enableval])
                SET_IF_UNSET([enable_libwebpdemux], [$enableval])
                SET_IF_UNSET([enable_libwebpextras], [$enableval])
                SET_IF_UNSET([enable_libwebpmux], [$enableval])])
@@ -104,6 +106,7 @@ TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wall])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wconstant-conversion])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wdeclaration-after-statement])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wextra])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wextra-semi-stmt])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wfloat-conversion])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat -Wformat-nonliteral])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat -Wformat-security])
@@ -113,6 +116,7 @@ TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wold-style-definition])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wparentheses-equality])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wshadow])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wshorten-64-to-32])
+TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wstrict-prototypes])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wundef])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunreachable-code-aggressive])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wunreachable-code])
@@ -462,7 +466,7 @@ AC_ARG_ENABLE([sdl],
                               @<:@default=auto@:>@]))
 AS_IF([test "x$enable_sdl" != "xno"], [
   CLEAR_LIBVARS([SDL])
-  AC_PATH_PROGS([LIBSDL_CONFIG], [sdl-config])
+  AC_PATH_PROGS([LIBSDL_CONFIG], [sdl2-config])
   if test -n "$LIBSDL_CONFIG"; then
     SDL_INCLUDES=`$LIBSDL_CONFIG --cflags`
     SDL_LIBS="`$LIBSDL_CONFIG --libs`"
@@ -472,13 +476,12 @@ AS_IF([test "x$enable_sdl" != "xno"], [
 
   sdl_header="no"
   LIBCHECK_PROLOGUE([SDL])
-  AC_CHECK_HEADER([SDL/SDL.h], [sdl_header="SDL/SDL.h"],
-                  [AC_CHECK_HEADER([SDL.h], [sdl_header="SDL.h"],
-                  [AC_MSG_WARN(SDL library not available - no sdl.h)])])
+  AC_CHECK_HEADER([SDL2/SDL.h], [sdl_header="SDL2/SDL.h"],
+                  [AC_MSG_WARN(SDL2 library not available - no SDL.h)])
   if test x"$sdl_header" != "xno"; then
     AC_LANG_PUSH(C)
     SDL_SAVED_LIBS="$LIBS"
-    for lib in "" "-lSDL" "-lSDLmain -lSDL"; do
+    for lib in "" "-lSDL2" "-lSDL2main -lSDL2"; do
       LIBS="$SDL_SAVED_LIBS $lib"
       # Perform a full link to ensure SDL_main is resolved if needed.
       AC_LINK_IFELSE(
@@ -747,17 +750,21 @@ fi
 
 dnl =========================
 
+dnl Add an empty webp_libname_prefix variable for use in *.pc.in.
+AC_SUBST([webp_libname_prefix])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_HEADERS([src/webp/config.h])
 AC_CONFIG_FILES([Makefile src/Makefile man/Makefile \
                  examples/Makefile extras/Makefile imageio/Makefile \
+                 sharpyuv/Makefile sharpyuv/libsharpyuv.pc \
                  src/dec/Makefile src/enc/Makefile src/dsp/Makefile \
                  src/demux/Makefile src/mux/Makefile \
                  src/utils/Makefile \
                  src/libwebp.pc src/libwebpdecoder.pc \
                  src/demux/libwebpdemux.pc src/mux/libwebpmux.pc])
 
-
+dnl fix exports from MinGW builds
+AC_CONFIG_COMMANDS_POST([$SED -i 's/-DDLL_EXPORT/-DWEBP_DLL/' config.status])
 AC_OUTPUT
 
 AC_MSG_NOTICE([

doc/README

@@ -1,29 +0,0 @@
-
-Generate libwebp Container Spec Docs from Text Source
-=====================================================
-
-HTML generation requires kramdown [1], easily installed as a
-rubygem [2].  Rubygems installation should satisfy dependencies
-automatically.
-
-[1]: https://kramdown.gettalong.org/
-[2]: https://rubygems.org/
-
-HTML generation can then be done from the project root:
-
-$ kramdown doc/webp-container-spec.txt --template doc/template.html > \
-  doc/output/webp-container-spec.html
-
-kramdown can optionally syntax highlight code blocks, using CodeRay [3],
-a dependency of kramdown that rubygems will install automatically.  The
-following will apply inline CSS styling; an external stylesheet is not
-needed.
-
-$ kramdown doc/webp-lossless-bitstream-spec.txt --template \
-  doc/template.html --coderay-css style --coderay-line-numbers ' ' \
-  --coderay-default-lang c > \
-  doc/output/webp-lossless-bitstream-spec.html
-
-Optimally, use kramdown 0.13.7 or newer if syntax highlighting desired.
-
-[3]: https://github.com/rubychan/coderay

doc/api.md

@@ -0,0 +1,385 @@
+# WebP APIs
+
+## Encoding API
+
+The main encoding functions are available in the header src/webp/encode.h
+
+The ready-to-use ones are:
+
+```c
+size_t WebPEncodeRGB(const uint8_t* rgb, int width, int height, int stride,
+                     float quality_factor, uint8_t** output);
+size_t WebPEncodeBGR(const uint8_t* bgr, int width, int height, int stride,
+                     float quality_factor, uint8_t** output);
+size_t WebPEncodeRGBA(const uint8_t* rgba, int width, int height, int stride,
+                      float quality_factor, uint8_t** output);
+size_t WebPEncodeBGRA(const uint8_t* bgra, int width, int height, int stride,
+                      float quality_factor, uint8_t** output);
+```
+
+They will convert raw RGB samples to a WebP data. The only control supplied is
+the quality factor.
+
+There are some variants for using the lossless format:
+
+```c
+size_t WebPEncodeLosslessRGB(const uint8_t* rgb, int width, int height,
+                             int stride, uint8_t** output);
+size_t WebPEncodeLosslessBGR(const uint8_t* bgr, int width, int height,
+                             int stride, uint8_t** output);
+size_t WebPEncodeLosslessRGBA(const uint8_t* rgba, int width, int height,
+                              int stride, uint8_t** output);
+size_t WebPEncodeLosslessBGRA(const uint8_t* bgra, int width, int height,
+                              int stride, uint8_t** output);
+```
+
+Of course in this case, no quality factor is needed since the compression occurs
+without loss of the input values, at the expense of larger output sizes.
+
+### Advanced encoding API
+
+A more advanced API is based on the WebPConfig and WebPPicture structures.
+
+WebPConfig contains the encoding settings and is not tied to a particular
+picture. WebPPicture contains input data, on which some WebPConfig will be used
+for compression. The encoding flow looks like:
+
+```c
+#include <webp/encode.h>
+
+// Setup a config, starting form a preset and tuning some additional
+// parameters
+WebPConfig config;
+if (!WebPConfigPreset(&config, WEBP_PRESET_PHOTO, quality_factor)) {
+  return 0;   // version error
+}
+// ... additional tuning
+config.sns_strength = 90;
+config.filter_sharpness = 6;
+config_error = WebPValidateConfig(&config);  // not mandatory, but useful
+
+// Setup the input data
+WebPPicture pic;
+if (!WebPPictureInit(&pic)) {
+  return 0;  // version error
+}
+pic.width = width;
+pic.height = height;
+// allocated picture of dimension width x height
+if (!WebPPictureAlloc(&pic)) {
+  return 0;   // memory error
+}
+// at this point, 'pic' has been initialized as a container,
+// and can receive the Y/U/V samples.
+// Alternatively, one could use ready-made import functions like
+// WebPPictureImportRGB(), which will take care of memory allocation.
+// In any case, past this point, one will have to call
+// WebPPictureFree(&pic) to reclaim memory.
+
+// Set up a byte-output write method. WebPMemoryWriter, for instance.
+WebPMemoryWriter wrt;
+WebPMemoryWriterInit(&wrt);     // initialize 'wrt'
+
+pic.writer = MyFileWriter;
+pic.custom_ptr = my_opaque_structure_to_make_MyFileWriter_work;
+
+// Compress!
+int ok = WebPEncode(&config, &pic);   // ok = 0 => error occurred!
+WebPPictureFree(&pic);  // must be called independently of the 'ok' result.
+
+// output data should have been handled by the writer at that point.
+// -> compressed data is the memory buffer described by wrt.mem / wrt.size
+
+// deallocate the memory used by compressed data
+WebPMemoryWriterClear(&wrt);
+```
+
+## Decoding API
+
+This is mainly just one function to call:
+
+```c
+#include "webp/decode.h"
+uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
+                       int* width, int* height);
+```
+
+Please have a look at the file src/webp/decode.h for the details. There are
+variants for decoding in BGR/RGBA/ARGB/BGRA order, along with decoding to raw
+Y'CbCr samples. One can also decode the image directly into a pre-allocated
+buffer.
+
+To detect a WebP file and gather the picture's dimensions, the function:
+
+```c
+int WebPGetInfo(const uint8_t* data, size_t data_size,
+                int* width, int* height);
+```
+
+is supplied. No decoding is involved when using it.
+
+### Incremental decoding API
+
+In the case when data is being progressively transmitted, pictures can still be
+incrementally decoded using a slightly more complicated API. Decoder state is
+stored into an instance of the WebPIDecoder object. This object can be created
+with the purpose of decoding either RGB or Y'CbCr samples. For instance:
+
+```c
+WebPDecBuffer buffer;
+WebPInitDecBuffer(&buffer);
+buffer.colorspace = MODE_BGR;
+...
+WebPIDecoder* idec = WebPINewDecoder(&buffer);
+```
+
+As data is made progressively available, this incremental-decoder object can be
+used to decode the picture further. There are two (mutually exclusive) ways to
+pass freshly arrived data:
+
+either by appending the fresh bytes:
+
+```c
+WebPIAppend(idec, fresh_data, size_of_fresh_data);
+```
+
+or by just mentioning the new size of the transmitted data:
+
+```c
+WebPIUpdate(idec, buffer, size_of_transmitted_buffer);
+```
+
+Note that 'buffer' can be modified between each call to WebPIUpdate, in
+particular when the buffer is resized to accommodate larger data.
+
+These functions will return the decoding status: either VP8_STATUS_SUSPENDED if
+decoding is not finished yet or VP8_STATUS_OK when decoding is done. Any other
+status is an error condition.
+
+The 'idec' object must always be released (even upon an error condition) by
+calling: WebPIDelete(idec).
+
+To retrieve partially decoded picture samples, one must use the corresponding
+method: WebPIDecGetRGB or WebPIDecGetYUVA. It will return the last displayable
+pixel row.
+
+Lastly, note that decoding can also be performed into a pre-allocated pixel
+buffer. This buffer must be passed when creating a WebPIDecoder, calling
+WebPINewRGB() or WebPINewYUVA().
+
+Please have a look at the src/webp/decode.h header for further details.
+
+### Advanced Decoding API
+
+WebP decoding supports an advanced API which provides on-the-fly cropping and
+rescaling, something of great usefulness on memory-constrained environments like
+mobile phones. Basically, the memory usage will scale with the output's size,
+not the input's, when one only needs a quick preview or a zoomed in portion of
+an otherwise too-large picture. Some CPU can be saved too, incidentally.
+
+```c
+// A) Init a configuration object
+WebPDecoderConfig config;
+CHECK(WebPInitDecoderConfig(&config));
+
+// B) optional: retrieve the bitstream's features.
+CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK);
+
+// C) Adjust 'config' options, if needed
+config.options.no_fancy_upsampling = 1;
+config.options.use_scaling = 1;
+config.options.scaled_width = scaledWidth();
+config.options.scaled_height = scaledHeight();
+// etc.
+
+// D) Specify 'config' output options for specifying output colorspace.
+// Optionally the external image decode buffer can also be specified.
+config.output.colorspace = MODE_BGRA;
+// Optionally, the config.output can be pointed to an external buffer as
+// well for decoding the image. This externally supplied memory buffer
+// should be big enough to store the decoded picture.
+config.output.u.RGBA.rgba = (uint8_t*) memory_buffer;
+config.output.u.RGBA.stride = scanline_stride;
+config.output.u.RGBA.size = total_size_of_the_memory_buffer;
+config.output.is_external_memory = 1;
+
+// E) Decode the WebP image. There are two variants w.r.t decoding image.
+// The first one (E.1) decodes the full image and the second one (E.2) is
+// used to incrementally decode the image using small input buffers.
+// Any one of these steps can be used to decode the WebP image.
+
+// E.1) Decode full image.
+CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK);
+
+// E.2) Decode image incrementally.
+WebPIDecoder* const idec = WebPIDecode(NULL, NULL, &config);
+CHECK(idec != NULL);
+while (bytes_remaining > 0) {
+  VP8StatusCode status = WebPIAppend(idec, input, bytes_read);
+  if (status == VP8_STATUS_OK || status == VP8_STATUS_SUSPENDED) {
+    bytes_remaining -= bytes_read;
+  } else {
+    break;
+  }
+}
+WebPIDelete(idec);
+
+// F) Decoded image is now in config.output (and config.output.u.RGBA).
+// It can be saved, displayed or otherwise processed.
+
+// G) Reclaim memory allocated in config's object. It's safe to call
+// this function even if the memory is external and wasn't allocated
+// by WebPDecode().
+WebPFreeDecBuffer(&config.output);
+```
+
+## WebP Mux
+
+WebPMux is a set of two libraries 'Mux' and 'Demux' for creation, extraction and
+manipulation of an extended format WebP file, which can have features like color
+profile, metadata and animation. Reference command-line tools `webpmux` and
+`vwebp` as well as the WebP container specification
+'doc/webp-container-spec.txt' are also provided in this package, see the
+[tools documentation](tools.md).
+
+### Mux API
+
+The Mux API contains methods for adding data to and reading data from WebP
+files. This API currently supports XMP/EXIF metadata, ICC profile and animation.
+Other features may be added in subsequent releases.
+
+Example#1 (pseudo code): Creating a WebPMux object with image data, color
+profile and XMP metadata.
+
+```c
+int copy_data = 0;
+WebPMux* mux = WebPMuxNew();
+// ... (Prepare image data).
+WebPMuxSetImage(mux, &image, copy_data);
+// ... (Prepare ICC profile data).
+WebPMuxSetChunk(mux, "ICCP", &icc_profile, copy_data);
+// ... (Prepare XMP metadata).
+WebPMuxSetChunk(mux, "XMP ", &xmp, copy_data);
+// Get data from mux in WebP RIFF format.
+WebPMuxAssemble(mux, &output_data);
+WebPMuxDelete(mux);
+// ... (Consume output_data; e.g. write output_data.bytes to file).
+WebPDataClear(&output_data);
+```
+
+Example#2 (pseudo code): Get image and color profile data from a WebP file.
+
+```c
+int copy_data = 0;
+// ... (Read data from file).
+WebPMux* mux = WebPMuxCreate(&data, copy_data);
+WebPMuxGetFrame(mux, 1, &image);
+// ... (Consume image; e.g. call WebPDecode() to decode the data).
+WebPMuxGetChunk(mux, "ICCP", &icc_profile);
+// ... (Consume icc_profile).
+WebPMuxDelete(mux);
+free(data);
+```
+
+For a detailed Mux API reference, please refer to the header file
+(src/webp/mux.h).
+
+### Demux API
+
+The Demux API enables extraction of images and extended format data from WebP
+files. This API currently supports reading of XMP/EXIF metadata, ICC profile and
+animated images. Other features may be added in subsequent releases.
+
+Code example: Demuxing WebP data to extract all the frames, ICC profile and
+EXIF/XMP metadata.
+
+```c
+WebPDemuxer* demux = WebPDemux(&webp_data);
+uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
+uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
+// ... (Get information about the features present in the WebP file).
+uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
+
+// ... (Iterate over all frames).
+WebPIterator iter;
+if (WebPDemuxGetFrame(demux, 1, &iter)) {
+  do {
+    // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(),
+    // ... and get other frame properties like width, height, offsets etc.
+    // ... see 'struct WebPIterator' below for more info).
+  } while (WebPDemuxNextFrame(&iter));
+  WebPDemuxReleaseIterator(&iter);
+}
+
+// ... (Extract metadata).
+WebPChunkIterator chunk_iter;
+if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter);
+// ... (Consume the ICC profile in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter);
+// ... (Consume the EXIF metadata in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter);
+// ... (Consume the XMP metadata in 'chunk_iter.chunk').
+WebPDemuxReleaseChunkIterator(&chunk_iter);
+WebPDemuxDelete(demux);
+```
+
+For a detailed Demux API reference, please refer to the header file
+(src/webp/demux.h).
+
+## AnimEncoder API
+
+The AnimEncoder API can be used to create animated WebP images.
+
+Code example:
+
+```c
+WebPAnimEncoderOptions enc_options;
+WebPAnimEncoderOptionsInit(&enc_options);
+// ... (Tune 'enc_options' as needed).
+WebPAnimEncoder* enc = WebPAnimEncoderNew(width, height, &enc_options);
+while(<there are more frames>) {
+  WebPConfig config;
+  WebPConfigInit(&config);
+  // ... (Tune 'config' as needed).
+  WebPAnimEncoderAdd(enc, frame, duration, &config);
+}
+WebPAnimEncoderAssemble(enc, webp_data);
+WebPAnimEncoderDelete(enc);
+// ... (Write the 'webp_data' to a file, or re-mux it further).
+```
+
+For a detailed AnimEncoder API reference, please refer to the header file
+(src/webp/mux.h).
+
+## AnimDecoder API
+
+This AnimDecoder API allows decoding (possibly) animated WebP images.
+
+Code Example:
+
+```c
+WebPAnimDecoderOptions dec_options;
+WebPAnimDecoderOptionsInit(&dec_options);
+// Tune 'dec_options' as needed.
+WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options);
+WebPAnimInfo anim_info;
+WebPAnimDecoderGetInfo(dec, &anim_info);
+for (uint32_t i = 0; i < anim_info.loop_count; ++i) {
+  while (WebPAnimDecoderHasMoreFrames(dec)) {
+    uint8_t* buf;
+    int timestamp;
+    WebPAnimDecoderGetNext(dec, &buf, &timestamp);
+    // ... (Render 'buf' based on 'timestamp').
+    // ... (Do NOT free 'buf', as it is owned by 'dec').
+  }
+  WebPAnimDecoderReset(dec);
+}
+const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec);
+// ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data).
+WebPAnimDecoderDelete(dec);
+```
+
+For a detailed AnimDecoder API reference, please refer to the header file
+(src/webp/demux.h).

doc/building.md

@@ -0,0 +1,231 @@
+# Building
+
+## Windows build
+
+By running:
+
+```batch
+nmake /f Makefile.vc CFG=release-static RTLIBCFG=static OBJDIR=output
+```
+
+the directory `output\release-static\(x64|x86)\bin` will contain the tools
+cwebp.exe and dwebp.exe. The directory `output\release-static\(x64|x86)\lib`
+will contain the libwebp static library. The target architecture (x86/x64) is
+detected by Makefile.vc from the Visual Studio compiler (cl.exe) available in
+the system path.
+
+## Unix build using makefile.unix
+
+On platforms with GNU tools installed (gcc and make), running
+
+```shell
+make -f makefile.unix
+```
+
+will build the binaries examples/cwebp and examples/dwebp, along with the static
+library src/libwebp.a. No system-wide installation is supplied, as this is a
+simple alternative to the full installation system based on the autoconf tools
+(see below). Please refer to makefile.unix for additional details and
+customizations.
+
+## Using autoconf tools
+
+Prerequisites: a compiler (e.g., gcc), make, autoconf, automake, libtool.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install gcc make autoconf automake libtool
+```
+
+When building from git sources, you will need to run autogen.sh to generate the
+configure script.
+
+```shell
+./configure
+make
+make install
+```
+
+should be all you need to have the following files
+
+```
+/usr/local/include/webp/decode.h
+/usr/local/include/webp/encode.h
+/usr/local/include/webp/types.h
+/usr/local/lib/libwebp.*
+/usr/local/bin/cwebp
+/usr/local/bin/dwebp
+```
+
+installed.
+
+Note: A decode-only library, libwebpdecoder, is available using the
+`--enable-libwebpdecoder` flag. The encode library is built separately and can
+be installed independently using a minor modification in the corresponding
+Makefile.am configure files (see comments there). See `./configure --help` for
+more options.
+
+## Building for MIPS Linux
+
+MIPS Linux toolchain stable available releases can be found at:
+https://community.imgtec.com/developers/mips/tools/codescape-mips-sdk/available-releases/
+
+```shell
+# Add toolchain to PATH
+export PATH=$PATH:/path/to/toolchain/bin
+
+# 32-bit build for mips32r5 (p5600)
+HOST=mips-mti-linux-gnu
+MIPS_CFLAGS="-O3 -mips32r5 -mabi=32 -mtune=p5600 -mmsa -mfp64 \
+  -msched-weight -mload-store-pairs -fPIE"
+MIPS_LDFLAGS="-mips32r5 -mabi=32 -mmsa -mfp64 -pie"
+
+# 64-bit build for mips64r6 (i6400)
+HOST=mips-img-linux-gnu
+MIPS_CFLAGS="-O3 -mips64r6 -mabi=64 -mtune=i6400 -mmsa -mfp64 \
+  -msched-weight -mload-store-pairs -fPIE"
+MIPS_LDFLAGS="-mips64r6 -mabi=64 -mmsa -mfp64 -pie"
+
+./configure --host=${HOST} --build=`config.guess` \
+  CC="${HOST}-gcc -EL" \
+  CFLAGS="$MIPS_CFLAGS" \
+  LDFLAGS="$MIPS_LDFLAGS"
+make
+make install
+```
+
+## Building libwebp - Using vcpkg
+
+You can download and install libwebp using the
+[vcpkg](https://github.com/Microsoft/vcpkg) dependency manager:
+
+```shell
+git clone https://github.com/Microsoft/vcpkg.git
+cd vcpkg
+./bootstrap-vcpkg.sh
+./vcpkg integrate install
+./vcpkg install libwebp
+```
+
+The libwebp port in vcpkg is kept up to date by Microsoft team members and
+community contributors. If the version is out of date, please
+[create an issue or pull request](https://github.com/Microsoft/vcpkg) on the
+vcpkg repository.
+
+## CMake
+
+With CMake, you can compile libwebp, cwebp, dwebp, gif2webp, img2webp, webpinfo
+and the JS bindings.
+
+Prerequisites: a compiler (e.g., gcc with autotools) and CMake.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install build-essential cmake
+```
+
+When building from git sources, you will need to run cmake to generate the
+makefiles.
+
+```shell
+mkdir build && cd build && cmake ../
+make
+make install
+```
+
+If you also want any of the executables, you will need to enable them through
+CMake, e.g.:
+
+```shell
+cmake -DWEBP_BUILD_CWEBP=ON -DWEBP_BUILD_DWEBP=ON ../
+```
+
+or through your favorite interface (like ccmake or cmake-qt-gui).
+
+Use option `-DWEBP_UNICODE=ON` for Unicode support on Windows (with chcp 65001).
+
+Finally, once installed, you can also use WebP in your CMake project by doing:
+
+```cmake
+find_package(WebP)
+```
+
+which will define the CMake variables WebP_INCLUDE_DIRS and WebP_LIBRARIES.
+
+## Gradle
+
+The support for Gradle is minimal: it only helps you compile libwebp, cwebp and
+dwebp and webpmux_example.
+
+Prerequisites: a compiler (e.g., gcc with autotools) and gradle.
+
+On a Debian-like system the following should install everything you need for a
+minimal build:
+
+```shell
+$ sudo apt-get install build-essential gradle
+```
+
+When building from git sources, you will need to run the Gradle wrapper with the
+appropriate target, e.g. :
+
+```shell
+./gradlew buildAllExecutables
+```
+
+## SWIG bindings
+
+To generate language bindings from swig/libwebp.swig at least swig-1.3
+(http://www.swig.org) is required.
+
+Currently the following functions are mapped:
+
+Decode:
+
+```
+WebPGetDecoderVersion
+WebPGetInfo
+WebPDecodeRGBA
+WebPDecodeARGB
+WebPDecodeBGRA
+WebPDecodeBGR
+WebPDecodeRGB
+```
+
+Encode:
+
+```
+WebPGetEncoderVersion
+WebPEncodeRGBA
+WebPEncodeBGRA
+WebPEncodeRGB
+WebPEncodeBGR
+WebPEncodeLosslessRGBA
+WebPEncodeLosslessBGRA
+WebPEncodeLosslessRGB
+WebPEncodeLosslessBGR
+```
+
+See also the [swig documentation](../swig/README.md) for more detailed build
+instructions and usage examples.
+
+### Java bindings
+
+To build the swig-generated JNI wrapper code at least JDK-1.5 (or equivalent) is
+necessary for enum support. The output is intended to be a shared object / DLL
+that can be loaded via `System.loadLibrary("webp_jni")`.
+
+### Python bindings
+
+To build the swig-generated Python extension code at least Python 2.6 is
+required. Python < 2.6 may build with some minor changes to libwebp.swig or the
+generated code, but is untested.
+
+## Javascript decoder
+
+Libwebp can be compiled into a JavaScript decoder using Emscripten and CMake.
+See the [corresponding documentation](../webp_js/README.md)

doc/specs_generation.md

@@ -0,0 +1,27 @@
+# Generate libwebp Container Spec Docs from Text Source
+
+HTML generation requires [kramdown](https://kramdown.gettalong.org/), easily
+installed as a [rubygem](https://rubygems.org/). Rubygems installation should
+satisfy dependencies automatically.
+
+HTML generation can then be done from the project root:
+
+```shell
+$ kramdown doc/webp-container-spec.txt --template doc/template.html > \
+  doc/output/webp-container-spec.html
+```
+
+kramdown can optionally syntax highlight code blocks, using
+[CodeRay](https://github.com/rubychan/coderay), a dependency of kramdown that
+rubygems will install automatically. The following will apply inline CSS
+styling; an external stylesheet is not needed.
+
+```shell
+$ kramdown doc/webp-lossless-bitstream-spec.txt \
+  --template doc/template.html \
+  -x syntax-coderay --syntax-highlighter coderay \
+  --syntax-highlighter-opts "{default_lang: c, line_numbers: , css: style}" \
+  > doc/output/webp-lossless-bitstream-spec.html
+```
+
+Optimally, use kramdown 0.13.7 or newer if syntax highlighting desired.

doc/tools.md

@@ -0,0 +1,519 @@
+# WebP tools
+
+## Encoding tool
+
+The examples/ directory contains tools for encoding (cwebp) and decoding (dwebp)
+images.
+
+The easiest use should look like:
+
+```shell
+cwebp input.png -q 80 -o output.webp
+```
+
+which will convert the input file to a WebP file using a quality factor of 80 on
+a 0->100 scale (0 being the lowest quality, 100 being the best. Default value is
+75).
+
+You might want to try the `-lossless` flag too, which will compress the source
+(in RGBA format) without any loss. The `-q` quality parameter will in this case
+control the amount of processing time spent trying to make the output file as
+small as possible.
+
+A longer list of options is available using the `-longhelp` command line flag:
+
+```shell
+> cwebp -longhelp
+Usage:
+ cwebp [-preset <...>] [options] in_file [-o out_file]
+```
+
+If input size (-s) for an image is not specified, it is assumed to be a PNG,
+JPEG, TIFF or WebP file. Note: Animated PNG and WebP files are not supported.
+
+Options:
+
+```
+-h / -help ............. short help
+-H / -longhelp ......... long help
+-q <float> ............. quality factor (0:small..100:big), default=75
+-alpha_q <int> ......... transparency-compression quality (0..100),
+                         default=100
+-preset <string> ....... preset setting, one of:
+                          default, photo, picture,
+                          drawing, icon, text
+   -preset must come first, as it overwrites other parameters
+-z <int> ............... activates lossless preset with given
+                         level in [0:fast, ..., 9:slowest]
+
+-m <int> ............... compression method (0=fast, 6=slowest), default=4
+-segments <int> ........ number of segments to use (1..4), default=4
+-size <int> ............ target size (in bytes)
+-psnr <float> .......... target PSNR (in dB. typically: 42)
+
+-s <int> <int> ......... input size (width x height) for YUV
+-sns <int> ............. spatial noise shaping (0:off, 100:max), default=50
+-f <int> ............... filter strength (0=off..100), default=60
+-sharpness <int> ....... filter sharpness (0:most .. 7:least sharp), default=0
+-strong ................ use strong filter instead of simple (default)
+-nostrong .............. use simple filter instead of strong
+-sharp_yuv ............. use sharper (and slower) RGB->YUV conversion
+-partition_limit <int> . limit quality to fit the 512k limit on
+                         the first partition (0=no degradation ... 100=full)
+-pass <int> ............ analysis pass number (1..10)
+-qrange <min> <max> .... specifies the permissible quality range
+                         (default: 0 100)
+-crop <x> <y> <w> <h> .. crop picture with the given rectangle
+-resize <w> <h> ........ resize picture (*after* any cropping)
+-mt .................... use multi-threading if available
+-low_memory ............ reduce memory usage (slower encoding)
+-map <int> ............. print map of extra info
+-print_psnr ............ prints averaged PSNR distortion
+-print_ssim ............ prints averaged SSIM distortion
+-print_lsim ............ prints local-similarity distortion
+-d <file.pgm> .......... dump the compressed output (PGM file)
+-alpha_method <int> .... transparency-compression method (0..1), default=1
+-alpha_filter <string> . predictive filtering for alpha plane,
+                         one of: none, fast (default) or best
+-exact ................. preserve RGB values in transparent area, default=off
+-blend_alpha <hex> ..... blend colors against background color
+                         expressed as RGB values written in
+                         hexadecimal, e.g. 0xc0e0d0 for red=0xc0
+                         green=0xe0 and blue=0xd0
+-noalpha ............... discard any transparency information
+-lossless .............. encode image losslessly, default=off
+-near_lossless <int> ... use near-lossless image preprocessing
+                         (0..100=off), default=100
+-hint <string> ......... specify image characteristics hint,
+                         one of: photo, picture or graph
+
+-metadata <string> ..... comma separated list of metadata to
+                         copy from the input to the output if present.
+                         Valid values: all, none (default), exif, icc, xmp
+
+-short ................. condense printed message
+-quiet ................. don't print anything
+-version ............... print version number and exit
+-noasm ................. disable all assembly optimizations
+-v ..................... verbose, e.g. print encoding/decoding times
+-progress .............. report encoding progress
+```
+
+Experimental Options:
+
+```
+-jpeg_like ............. roughly match expected JPEG size
+-af .................... auto-adjust filter strength
+-pre <int> ............. pre-processing filter
+```
+
+The main options you might want to try in order to further tune the visual
+quality are:
+
+-preset -sns -f -m
+
+Namely:
+
+*   `preset` will set up a default encoding configuration targeting a particular
+    type of input. It should appear first in the list of options, so that
+    subsequent options can take effect on top of this preset. Default value is
+    'default'.
+*   `sns` will progressively turn on (when going from 0 to 100) some additional
+    visual optimizations (like: segmentation map re-enforcement). This option
+    will balance the bit allocation differently. It tries to take bits from the
+    "easy" parts of the picture and use them in the "difficult" ones instead.
+    Usually, raising the sns value (at fixed -q value) leads to larger files,
+    but with better quality. Typical value is around '75'.
+*   `f` option directly links to the filtering strength used by the codec's
+    in-loop processing. The higher the value, the smoother the highly-compressed
+    area will look. This is particularly useful when aiming at very small files.
+    Typical values are around 20-30. Note that using the option
+    -strong/-nostrong will change the type of filtering. Use "-f 0" to turn
+    filtering off.
+*   `m` controls the trade-off between encoding speed and quality. Default is 4.
+    You can try -m 5 or -m 6 to explore more (time-consuming) encoding
+    possibilities. A lower value will result in faster encoding at the expense
+    of quality.
+
+## Decoding tool
+
+There is a decoding sample in examples/dwebp.c which will take a .webp file and
+decode it to a PNG image file (amongst other formats). This is simply to
+demonstrate the use of the API. You can verify the file test.webp decodes to
+exactly the same as test_ref.ppm by using:
+
+```shell
+cd examples
+./dwebp test.webp -ppm -o test.ppm
+diff test.ppm test_ref.ppm
+```
+
+The full list of options is available using -h:
+
+```shell
+> dwebp -h
+Usage: dwebp in_file [options] [-o out_file]
+```
+
+Decodes the WebP image file to PNG format [Default]. Note: Animated WebP files
+are not supported.
+
+Use following options to convert into alternate image formats:
+
+```
+-pam ......... save the raw RGBA samples as a color PAM
+-ppm ......... save the raw RGB samples as a color PPM
+-bmp ......... save as uncompressed BMP format
+-tiff ........ save as uncompressed TIFF format
+-pgm ......... save the raw YUV samples as a grayscale PGM
+               file with IMC4 layout
+-yuv ......... save the raw YUV samples in flat layout
+```
+
+Other options are:
+
+```
+-version ..... print version number and exit
+-nofancy ..... don't use the fancy YUV420 upscaler
+-nofilter .... disable in-loop filtering
+-nodither .... disable dithering
+-dither <d> .. dithering strength (in 0..100)
+-alpha_dither  use alpha-plane dithering if needed
+-mt .......... use multi-threading
+-crop <x> <y> <w> <h> ... crop output with the given rectangle
+-resize <w> <h> ......... resize output (*after* any cropping)
+-flip ........ flip the output vertically
+-alpha ....... only save the alpha plane
+-incremental . use incremental decoding (useful for tests)
+-h ........... this help message
+-v ........... verbose (e.g. print encoding/decoding times)
+-quiet ....... quiet mode, don't print anything
+-noasm ....... disable all assembly optimizations
+```
+
+## WebP file analysis tool
+
+`webpinfo` can be used to print out the chunk level structure and bitstream
+header information of WebP files. It can also check if the files are of valid
+WebP format.
+
+Usage:
+
+```shell
+webpinfo [options] in_files
+```
+
+Note: there could be multiple input files; options must come before input files.
+
+Options:
+
+```
+-version ........... Print version number and exit.
+-quiet ............. Do not show chunk parsing information.
+-diag .............. Show parsing error diagnosis.
+-summary ........... Show chunk stats summary.
+-bitstream_info .... Parse bitstream header.
+```
+
+## Visualization tool
+
+There's a little self-serve visualization tool called 'vwebp' under the
+examples/ directory. It uses OpenGL to open a simple drawing window and show a
+decoded WebP file. It's not yet integrated in the automake build system, but you
+can try to manually compile it using the recommendations below.
+
+Usage:
+
+```shell
+vwebp in_file [options]
+```
+
+Decodes the WebP image file and visualize it using OpenGL
+
+Options are:
+
+```
+-version ..... print version number and exit
+-noicc ....... don't use the icc profile if present
+-nofancy ..... don't use the fancy YUV420 upscaler
+-nofilter .... disable in-loop filtering
+-dither <int>  dithering strength (0..100), default=50
+-noalphadither disable alpha plane dithering
+-usebgcolor .. display background color
+-mt .......... use multi-threading
+-info ........ print info
+-h ........... this help message
+```
+
+Keyboard shortcuts:
+
+```
+'c' ................ toggle use of color profile
+'b' ................ toggle background color display
+'i' ................ overlay file information
+'d' ................ disable blending & disposal (debug)
+'q' / 'Q' / ESC .... quit
+```
+
+### Building
+
+Prerequisites:
+
+1.  OpenGL & OpenGL Utility Toolkit (GLUT)
+
+    Linux: `sudo apt-get install freeglut3-dev mesa-common-dev`
+
+    Mac + Xcode: These libraries should be available in the OpenGL / GLUT
+    frameworks.
+
+    Windows: http://freeglut.sourceforge.net/index.php#download
+
+2.  (Optional) qcms (Quick Color Management System)
+
+    1.  Download qcms from Mozilla / Chromium:
+        https://hg.mozilla.org/mozilla-central/file/0e7639e3bdfb/gfx/qcms
+        https://source.chromium.org/chromium/chromium/src/+/main:third_party/qcms/;drc=d4a2f8e1ed461d8fc05ed88d1ae2dc94c9773825
+    2.  Build and archive the source files as libqcms.a / qcms.lib
+    3.  Update makefile.unix / Makefile.vc
+        1.  Define WEBP_HAVE_QCMS
+        2.  Update include / library paths to reference the qcms directory.
+
+Build using makefile.unix / Makefile.vc:
+
+```shell
+$ make -f makefile.unix examples/vwebp
+> nmake /f Makefile.vc CFG=release-static \
+    ../obj/x64/release-static/bin/vwebp.exe
+```
+
+## Animation creation tool
+
+The utility `img2webp` can turn a sequence of input images (PNG, JPEG, ...) into
+an animated WebP file. It offers fine control over duration, encoding modes,
+etc.
+
+Usage:
+
+```shell
+img2webp [file_options] [[frame_options] frame_file]... [-o webp_file]
+```
+
+File-level options (only used at the start of compression):
+
+```
+-min_size ............ minimize size
+-kmax <int> .......... maximum number of frame between key-frames
+                        (0=only keyframes)
+-kmin <int> .......... minimum number of frame between key-frames
+                        (0=disable key-frames altogether)
+-mixed ............... use mixed lossy/lossless automatic mode
+-near_lossless <int> . use near-lossless image preprocessing
+                       (0..100=off), default=100
+-sharp_yuv ........... use sharper (and slower) RGB->YUV conversion
+                       (lossy only)
+-loop <int> .......... loop count (default: 0, = infinite loop)
+-v ................... verbose mode
+-h ................... this help
+-version ............. print version number and exit
+```
+
+Per-frame options (only used for subsequent images input):
+
+```
+-d <int> ............. frame duration in ms (default: 100)
+-lossless ............ use lossless mode (default)
+-lossy ............... use lossy mode
+-q <float> ........... quality
+-m <int> ............. method to use
+-exact, -noexact ..... preserve or alter RGB values in transparent area
+                       (default: -noexact, may cause artifacts
+                                 with lossy animations)
+```
+
+example: `img2webp -loop 2 in0.png -lossy in1.jpg -d 80 in2.tiff -o out.webp`
+
+Note: if a single file name is passed as the argument, the arguments will be
+tokenized from this file. The file name must not start with the character '-'.
+
+## Animated GIF conversion
+
+Animated GIF files can be converted to WebP files with animation using the
+gif2webp utility available under examples/. The files can then be viewed using
+vwebp.
+
+Usage:
+
+```shell
+gif2webp [options] gif_file -o webp_file
+```
+
+Options:
+
+```
+-h / -help ............. this help
+-lossy ................. encode image using lossy compression
+-mixed ................. for each frame in the image, pick lossy
+                         or lossless compression heuristically
+-q <float> ............. quality factor (0:small..100:big)
+-m <int> ............... compression method (0=fast, 6=slowest)
+-min_size .............. minimize output size (default:off)
+                         lossless compression by default; can be
+                         combined with -q, -m, -lossy or -mixed
+                         options
+-kmin <int> ............ min distance between key frames
+-kmax <int> ............ max distance between key frames
+-f <int> ............... filter strength (0=off..100)
+-metadata <string> ..... comma separated list of metadata to
+                         copy from the input to the output if present
+                         Valid values: all, none, icc, xmp (default)
+-loop_compatibility .... use compatibility mode for Chrome
+                         version prior to M62 (inclusive)
+-mt .................... use multi-threading if available
+
+-version ............... print version number and exit
+-v ..................... verbose
+-quiet ................. don't print anything
+```
+
+### Building
+
+With the libgif development files installed, gif2webp can be built using
+makefile.unix:
+
+```shell
+$ make -f makefile.unix examples/gif2webp
+```
+
+or using autoconf:
+
+```shell
+$ ./configure --enable-everything
+$ make
+```
+
+## Comparison of animated images
+
+Test utility anim_diff under examples/ can be used to compare two animated
+images (each can be GIF or WebP).
+
+Usage:
+
+```shell
+anim_diff <image1> <image2> [options]
+```
+
+Options:
+
+```
+-dump_frames <folder> dump decoded frames in PAM format
+-min_psnr <float> ... minimum per-frame PSNR
+-raw_comparison ..... if this flag is not used, RGB is
+                      premultiplied before comparison
+-max_diff <int> ..... maximum allowed difference per channel
+                      between corresponding pixels in subsequent
+                      frames
+-h .................. this help
+-version ............ print version number and exit
+```
+
+### Building
+
+With the libgif development files installed, anim_diff can be built using
+makefile.unix:
+
+```shell
+$ make -f makefile.unix examples/anim_diff
+```
+
+or using autoconf:
+
+```shell
+$ ./configure --enable-everything
+$ make
+```
+
+## WebP Mux tool
+
+The examples/ directory contains a tool (webpmux) for manipulating WebP files.
+The webpmux tool can be used to create an extended format WebP file and also to
+extract or strip relevant data from such a file.
+
+A list of options is available using the -help command line flag:
+
+```shell
+> webpmux -help
+Usage: webpmux -get GET_OPTIONS INPUT -o OUTPUT
+       webpmux -set SET_OPTIONS INPUT -o OUTPUT
+       webpmux -duration DURATION_OPTIONS [-duration ...]
+               INPUT -o OUTPUT
+       webpmux -strip STRIP_OPTIONS INPUT -o OUTPUT
+       webpmux -frame FRAME_OPTIONS [-frame...] [-loop LOOP_COUNT]
+               [-bgcolor BACKGROUND_COLOR] -o OUTPUT
+       webpmux -info INPUT
+       webpmux [-h|-help]
+       webpmux -version
+       webpmux argument_file_name
+
+GET_OPTIONS:
+ Extract relevant data:
+   icc       get ICC profile
+   exif      get EXIF metadata
+   xmp       get XMP metadata
+   frame n   get nth frame
+
+SET_OPTIONS:
+ Set color profile/metadata/parameters:
+   loop LOOP_COUNT            set the loop count
+   bgcolor BACKGROUND_COLOR   set the animation background color
+   icc  file.icc              set ICC profile
+   exif file.exif             set EXIF metadata
+   xmp  file.xmp              set XMP metadata
+   where:    'file.icc' contains the ICC profile to be set,
+             'file.exif' contains the EXIF metadata to be set
+             'file.xmp' contains the XMP metadata to be set
+
+DURATION_OPTIONS:
+ Set duration of selected frames:
+   duration            set duration for all frames
+   duration,frame      set duration of a particular frame
+   duration,start,end  set duration of frames in the
+                        interval [start,end])
+   where: 'duration' is the duration in milliseconds
+          'start' is the start frame index
+          'end' is the inclusive end frame index
+           The special 'end' value '0' means: last frame.
+
+STRIP_OPTIONS:
+ Strip color profile/metadata:
+   icc       strip ICC profile
+   exif      strip EXIF metadata
+   xmp       strip XMP metadata
+
+FRAME_OPTIONS(i):
+ Create animation:
+   file_i +di[+xi+yi[+mi[bi]]]
+   where:    'file_i' is the i'th animation frame (WebP format),
+             'di' is the pause duration before next frame,
+             'xi','yi' specify the image offset for this frame,
+             'mi' is the dispose method for this frame (0 or 1),
+             'bi' is the blending method for this frame (+b or -b)
+
+LOOP_COUNT:
+ Number of times to repeat the animation.
+ Valid range is 0 to 65535 [Default: 0 (infinite)].
+
+BACKGROUND_COLOR:
+ Background color of the canvas.
+  A,R,G,B
+  where:    'A', 'R', 'G' and 'B' are integers in the range 0 to 255 specifying
+            the Alpha, Red, Green and Blue component values respectively
+            [Default: 255,255,255,255]
+
+INPUT & OUTPUT are in WebP format.
+
+Note: The nature of EXIF, XMP and ICC data is not checked and is assumed to be
+valid.
+
+Note: if a single file name is passed as the argument, the arguments will be
+tokenized from this file. The file name must not start with the character '-'.
+```

doc/webp-container-spec.txt

@@ -4,8 +4,8 @@ Although you may be viewing an alternate representation, this document
 is sourced in Markdown, a light-duty markup scheme, and is optimized for
 the [kramdown](https://kramdown.gettalong.org/) transformer.
 
-See the accompanying README. External link targets are referenced at the
-end of this file.
+See the accompanying specs_generation.md. External link targets are referenced
+at the end of this file.
 
 -->
 
@@ -20,46 +20,48 @@ WebP Container Specification
 Introduction
 ------------
 
-WebP is an image format that uses either (i) the VP8 key frame encoding
-to compress image data in a lossy way, or (ii) the WebP lossless encoding
-(and possibly other encodings in the future). These encoding schemes should
-make it more efficient than currently used formats. It is optimized for fast
-image transfer over the network (e.g., for websites). The WebP format has
-feature parity (color profile, metadata, animation etc) with other formats as
-well. This document describes the structure of a WebP file.
+WebP is an image format that uses either (i) the VP8 key frame encoding to
+compress image data in a lossy way or (ii) the WebP lossless encoding. These
+encoding schemes should make it more efficient than older formats, such as JPEG,
+GIF, and PNG. It is optimized for fast image transfer over the network (for
+example, for websites). The WebP format has feature parity (color profile,
+metadata, animation, etc.) with other formats as well. This document describes
+the structure of a WebP file.
 
-The WebP container (i.e., RIFF container for WebP) allows feature support over
-and above the basic use case of WebP (i.e., a file containing a single image
-encoded as a VP8 key frame). The WebP container provides additional support
-for:
+The WebP container (that is, the RIFF container for WebP) allows feature support
+over and above the basic use case of WebP (that is, a file containing a single
+image encoded as a VP8 key frame). The WebP container provides additional
+support for the following:
 
-  * **Lossless compression.** An image can be losslessly compressed, using the
+  * Lossless Compression: An image can be losslessly compressed, using the
     WebP Lossless Format.
 
-  * **Metadata.** An image may have metadata stored in EXIF or XMP formats.
+  * Metadata: An image may have metadata stored in Exchangeable Image File
+    Format (Exif) or Extensible Metadata Platform (XMP) format.
 
-  * **Transparency.** An image may have transparency, i.e., an alpha channel.
+  * Transparency: An image may have transparency, that is, an alpha channel.
 
-  * **Color Profile.** An image may have an embedded ICC profile as described
+  * Color Profile: An image may have an embedded ICC profile as described
     by the [International Color Consortium][iccspec].
 
-  * **Animation.** An image may have multiple frames with pauses between them,
+  * Animation: An image may have multiple frames with pauses between them,
     making it an animation.
 
-The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
-"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
-document are to be interpreted as described in [RFC 2119][].
+Terminology & Basics
+--------------------
+
+The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
+"SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this
+document are to be interpreted as described in BCP 14 [RFC 2119][] [RFC 8174][]
+when, and only when, they appear in all capitals, as shown here.
+
+A WebP file contains either a still image (that is, an encoded matrix of pixels)
+or an [animation](#animation). Optionally, it can also contain transparency
+information, a color profile and metadata. We refer to the matrix of pixels as
+the _canvas_ of the image.
 
 Bit numbering in chunk diagrams starts at `0` for the most significant bit
-('MSB 0') as described in [RFC 1166][].
-
-Terminology & Basics
-------------------------
-
-A WebP file contains either a still image (i.e., an encoded matrix of pixels)
-or an [animation](#animation). Optionally, it can also contain transparency
-information, color profile and metadata. In case we need to refer only to the
-matrix of pixels, we will call it the _canvas_ of the image.
+('MSB 0'), as described in [RFC 1166][].
 
 Below are additional terms used throughout this document:
 
@@ -82,19 +84,25 @@ _uint32_
 
 _FourCC_
 
-: A _FourCC_ (four-character code) is a _uint32_ created by concatenating four
-  ASCII characters in little-endian order.
+: A four-character code (FourCC) is a _uint32_ created by concatenating four
+  ASCII characters in little-endian order. This means 'aaaa' (0x61616161) and
+ 'AAAA' (0x41414141) are treated as different _FourCCs_.
 
 _1-based_
 
-: An unsigned integer field storing values offset by `-1`. e.g., Such a field
-  would store value _25_ as _24_.
+: An unsigned integer field storing values offset by `-1`, for example, such a
+  field would store value _25_ as _24_.
+
+_ChunkHeader('ABCD')_
+
+: Used to describe the _FourCC_ and _Chunk Size_ header of individual chunks,
+  where 'ABCD' is the FourCC for the chunk. This element's size is 8 bytes.
 
 
 RIFF File Format
 ----------------
 
-The WebP file format is based on the RIFF (resource interchange file format)
+The WebP file format is based on the RIFF (Resource Interchange File Format)
 document format.
 
 The basic element of a RIFF file is a _chunk_. It consists of:
@@ -106,7 +114,7 @@ The basic element of a RIFF file is a _chunk_. It consists of:
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Chunk Size                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                         Chunk Payload                         |
+    :                         Chunk Payload                         :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
 Chunk FourCC: 32 bits
@@ -115,21 +123,15 @@ Chunk FourCC: 32 bits
 
 Chunk Size: 32 bits (_uint32_)
 
-: The size of the chunk not including this field, the chunk identifier or
-  padding.
+: The size of the chunk in bytes, not including this field, the chunk
+  identifier, or padding.
 
 Chunk Payload: _Chunk Size_ bytes
 
-: The data payload. If _Chunk Size_ is odd, a single padding byte -- that
-  SHOULD be `0` -- is added.
+: The data payload. If _Chunk Size_ is odd, a single padding byte -- which MUST
+  be `0` to conform with RIFF -- is added.
 
-_ChunkHeader('ABCD')_
-
-: This is used to describe the _FourCC_ and _Chunk Size_ header of individual
-  chunks, where 'ABCD' is the FourCC for the chunk. This element's
-  size is 8 bytes.
-
-**Note:** RIFF has a convention that all-uppercase chunk FourCCs are standard
+**Note**: RIFF has a convention that all-uppercase chunk FourCCs are standard
 chunks that apply to any RIFF file format, while FourCCs specific to a file
 format are all lowercase. WebP does not follow this convention.
 
@@ -149,23 +151,25 @@ WebP File Header
 
 'RIFF': 32 bits
 
-: The ASCII characters 'R' 'I' 'F' 'F'.
+: The ASCII characters 'R', 'I', 'F', 'F'.
 
 File Size: 32 bits (_uint32_)
 
-: The size of the file in bytes starting at offset 8. The maximum value of
+: The size of the file in bytes, starting at offset 8. The maximum value of
   this field is 2^32 minus 10 bytes and thus the size of the whole file is at
-  most 4GiB minus 2 bytes.
+  most 4 GiB minus 2 bytes.
 
 'WEBP': 32 bits
 
-: The ASCII characters 'W' 'E' 'B' 'P'.
+: The ASCII characters 'W', 'E', 'B', 'P'.
 
 A WebP file MUST begin with a RIFF header with the FourCC 'WEBP'. The file size
 in the header is the total size of the chunks that follow plus `4` bytes for
-the 'WEBP' FourCC. The file SHOULD NOT contain anything after it. As the size
-of any chunk is even, the size given by the RIFF header is also even. The
-contents of individual chunks will be described in the following sections.
+the 'WEBP' FourCC. The file SHOULD NOT contain any data after the data
+specified by _File Size_. Readers MAY parse such files, ignoring the trailing
+data. As the size of any chunk is even, the size given by the RIFF header is
+also even. The contents of individual chunks are described in the following
+sections.
 
 
 Simple File Format (Lossy)
@@ -180,37 +184,43 @@ Simple WebP (lossy) file format:
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
     |                    WebP file header (12 bytes)                |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                          VP8 chunk                            |
+    :                        'VP8 ' Chunk                           :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
-VP8 chunk:
+'VP8 ' Chunk:
 
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('VP8 ')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                           VP8 data                            |
+    :                           VP8 data                            :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
 VP8 data: _Chunk Size_ bytes
 
 : VP8 bitstream data.
 
-The VP8 bitstream format specification can be found at [VP8 Data Format and
-Decoding Guide][vp8spec]. Note that the VP8 frame header contains the VP8 frame
+Note that the fourth character in the 'VP8 ' FourCC is an ASCII space (0x20).
+
+The VP8 bitstream format specification is described in [VP8 Data Format and
+Decoding Guide][rfc 6386]. Note that the VP8 frame header contains the VP8 frame
 width and height. That is assumed to be the width and height of the canvas.
 
-The VP8 specification describes how to decode the image into Y'CbCr
-format. To convert to RGB, Rec. 601 SHOULD be used.
+The VP8 specification describes how to decode the image into Y'CbCr format. To
+convert to RGB, [Recommendation BT.601][rec601] SHOULD be used. Applications MAY
+use another conversion method, but visual results may differ among decoders.
 
 
 Simple File Format (Lossless)
 -----------------------------
 
-**Note:** Older readers may not support files using the lossless format.
+**Note**: Older readers may not support files using the lossless format.
 
 This layout SHOULD be used if the image requires _lossless_ encoding (with an
 optional transparency channel) and does not require advanced features provided
@@ -221,19 +231,22 @@ Simple WebP (lossless) file format:
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
     |                    WebP file header (12 bytes)                |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                          VP8L chunk                           |
+    :                         'VP8L' Chunk                          :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
-VP8L chunk:
+'VP8L' Chunk:
 
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('VP8L')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                           VP8L data                           |
+    :                           VP8L data                           :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
 VP8L data: _Chunk Size_ bytes
@@ -249,21 +262,21 @@ and height of the canvas.
 Extended File Format
 --------------------
 
-**Note:** Older readers may not support files using the extended format.
+**Note**: Older readers may not support files using the extended format.
 
 An extended format file consists of:
 
-  * A 'VP8X' chunk with information about features used in the file.
+  * A 'VP8X' Chunk with information about features used in the file.
 
-  * An optional 'ICCP' chunk with color profile.
+  * An optional 'ICCP' Chunk with a color profile.
 
-  * An optional 'ANIM' chunk with animation control data.
+  * An optional 'ANIM' Chunk with animation control data.
 
   * Image data.
 
-  * An optional 'EXIF' chunk with EXIF metadata.
+  * An optional 'EXIF' Chunk with Exif metadata.
 
-  * An optional 'XMP ' chunk with XMP metadata.
+  * An optional 'XMP ' Chunk with XMP metadata.
 
   * An optional list of [unknown chunks](#unknown-chunks).
 
@@ -277,15 +290,18 @@ up of:
 For an _animated image_, the _image data_ consists of multiple frames. More
 details about frames can be found in the [Animation](#animation) section.
 
-All chunks SHOULD be placed in the same order as listed above. If a chunk
-appears in the wrong place, the file is invalid, but readers MAY parse the
-file, ignoring the chunks that come too late.
+All chunks necessary for reconstruction and color correction, that is, 'VP8X',
+'ICCP', 'ANIM', 'ANMF', 'ALPH', 'VP8 ', and 'VP8L', MUST appear in the order
+described earlier. Readers SHOULD fail when chunks necessary for reconstruction
+and color correction are out of order.
 
-**Rationale:** Setting the order of chunks should allow quicker file
-parsing. For example, if an 'ALPH' chunk does not appear in its required
-position, a decoder can choose to stop searching for it. The rule of
-ignoring late chunks should make programs that need to do a full search
-give the same results as the ones stopping early.
+[Metadata](#metadata) and [unknown chunks](#unknown-chunks) MAY appear out of
+order.
+
+**Rationale:** The chunks necessary for reconstruction should appear first in
+the file to allow a reader to begin decoding an image before receiving all of
+the data. An application may benefit from varying the order of metadata and
+custom chunks to suit the implementation.
 
 Extended WebP file header:
 {:#extended_header}
@@ -293,9 +309,12 @@ Extended WebP file header:
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    |                                                               |
     |                   WebP file header (12 bytes)                 |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('VP8X')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Rsv|I|L|E|X|A|R|                   Reserved                    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -306,20 +325,20 @@ Extended WebP file header:
 
 Reserved (Rsv): 2 bits
 
-: SHOULD be `0`.
+: MUST be `0`. Readers MUST ignore this field.
 
 ICC profile (I): 1 bit
 
-: Set if the file contains an ICC profile.
+: Set if the file contains an 'ICCP' Chunk.
 
 Alpha (L): 1 bit
 
 : Set if any of the frames of the image contain transparency information
   ("alpha").
 
-EXIF metadata (E): 1 bit
+Exif metadata (E): 1 bit
 
-: Set if the file contains EXIF metadata.
+: Set if the file contains Exif metadata.
 
 XMP metadata (X): 1 bit
 
@@ -327,38 +346,38 @@ XMP metadata (X): 1 bit
 
 Animation (A): 1 bit
 
-: Set if this is an animated image. Data in 'ANIM' and 'ANMF' chunks should be
+: Set if this is an animated image. Data in 'ANIM' and 'ANMF' Chunks should be
   used to control the animation.
 
 Reserved (R): 1 bit
 
-: SHOULD be `0`.
+: MUST be `0`. Readers MUST ignore this field.
 
 Reserved: 24 bits
 
-: SHOULD be `0`.
+: MUST be `0`. Readers MUST ignore this field.
 
 Canvas Width Minus One: 24 bits
 
 : _1-based_ width of the canvas in pixels.
-  The actual canvas width is '1 + Canvas Width Minus One'
+  The actual canvas width is `1 + Canvas Width Minus One`.
 
 Canvas Height Minus One: 24 bits
 
 : _1-based_ height of the canvas in pixels.
-  The actual canvas height is '1 + Canvas Height Minus One'
+  The actual canvas height is `1 + Canvas Height Minus One`.
 
 The product of _Canvas Width_ and _Canvas Height_ MUST be at most `2^32 - 1`.
 
-Future specifications MAY add more fields.
+Future specifications may add more fields. Unknown fields MUST be ignored.
 
 ### Chunks
 
 #### Animation
 
-An animation is controlled by ANIM and ANMF chunks.
+An animation is controlled by 'ANIM' and 'ANMF' Chunks.
 
-ANIM Chunk:
+'ANIM' Chunk:
 {:#anim_chunk}
 
 For an animated image, this chunk contains the _global parameters_ of the
@@ -368,6 +387,7 @@ animation.
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('ANIM')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Background Color                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -379,14 +399,14 @@ Background Color: 32 bits (_uint32_)
 : The default background color of the canvas in \[Blue, Green, Red, Alpha\]
   byte order. This color MAY be used to fill the unused space on the canvas
   around the frames, as well as the transparent pixels of the first frame.
-  Background color is also used when disposal method is `1`.
+  The background color is also used when the Disposal method is `1`.
 
-**Note**:
+**Notes**:
 
-  * Background color MAY contain a transparency value (alpha), even if the
-    _Alpha_ flag in [VP8X chunk](#extended_header) is unset.
+  * The background color MAY contain a non-opaque alpha value, even if the
+    _Alpha_ flag in the ['VP8X' Chunk](#extended_header) is unset.
 
-  * Viewer applications SHOULD treat the background color value as a hint, and
+  * Viewer applications SHOULD treat the background color value as a hint and
     are not required to use it.
 
   * The canvas is cleared at the start of each loop. The background color MAY be
@@ -394,13 +414,14 @@ Background Color: 32 bits (_uint32_)
 
 Loop Count: 16 bits (_uint16_)
 
-: The number of times to loop the animation. `0` means infinitely.
+: The number of times to loop the animation. If it is `0`, this means
+  infinitely.
 
-This chunk MUST appear if the _Animation_ flag in the VP8X chunk is set.
-If the _Animation_ flag is not set and this chunk is present, it
-SHOULD be ignored.
+This chunk MUST appear if the _Animation_ flag in the 'VP8X' Chunk is set.
+If the _Animation_ flag is not set and this chunk is present, it MUST be
+ignored.
 
-ANMF chunk:
+'ANMF' Chunk:
 
 For animated images, this chunk contains information about a _single_ frame.
 If the _Animation flag_ is not set, then this chunk SHOULD NOT be present.
@@ -409,6 +430,7 @@ If the _Animation flag_ is not set, then this chunk SHOULD NOT be present.
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('ANMF')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                        Frame X                |             ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -418,47 +440,47 @@ If the _Animation flag_ is not set, then this chunk SHOULD NOT be present.
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                 Frame Duration                |  Reserved |B|D|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                         Frame Data                            |
+    :                         Frame Data                            :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
 Frame X: 24 bits (_uint24_)
 
-: The X coordinate of the upper left corner of the frame is `Frame X * 2`
+: The X coordinate of the upper left corner of the frame is `Frame X * 2`.
 
 Frame Y: 24 bits (_uint24_)
 
-: The Y coordinate of the upper left corner of the frame is `Frame Y * 2`
+: The Y coordinate of the upper left corner of the frame is `Frame Y * 2`.
 
 Frame Width Minus One: 24 bits (_uint24_)
 
 : The _1-based_ width of the frame.
-  The frame width is `1 + Frame Width Minus One`
+  The frame width is `1 + Frame Width Minus One`.
 
 Frame Height Minus One: 24 bits (_uint24_)
 
 : The _1-based_ height of the frame.
-  The frame height is `1 + Frame Height Minus One`
+  The frame height is `1 + Frame Height Minus One`.
 
 Frame Duration: 24 bits (_uint24_)
 
-: The time to wait before displaying the next frame, in 1 millisecond units.
-  Note the interpretation of frame duration of 0 (and often <= 10) is
-  implementation defined. Many tools and browsers assign a minimum duration
-  similar to GIF.
+: The time to wait before displaying the next frame, in 1-millisecond units.
+  Note that the interpretation of the Frame Duration of 0 (and often <= 10) is
+  defined by the implementation. Many tools and browsers assign a minimum
+  duration similar to GIF.
 
 Reserved: 6 bits
 
-: SHOULD be 0.
+: MUST be `0`. Readers MUST ignore this field.
 
 Blending method (B): 1 bit
 
 : Indicates how transparent pixels of _the current frame_ are to be blended
   with corresponding pixels of the previous canvas:
 
-    * `0`: Use alpha blending. After disposing of the previous frame, render the
+    * `0`: Use alpha-blending. After disposing of the previous frame, render the
       current frame on the canvas using [alpha-blending](#alpha-blending). If
-      the current frame does not have an alpha channel, assume alpha value of
-      255, effectively replacing the rectangle.
+      the current frame does not have an alpha channel, assume the alpha value
+      is 255, effectively replacing the rectangle.
 
     * `1`: Do not blend. After disposing of the previous frame, render the
       current frame on the canvas by overwriting the rectangle covered by the
@@ -471,20 +493,20 @@ Disposal method (D): 1 bit
 
     * `0`: Do not dispose. Leave the canvas as is.
 
-    * `1`: Dispose to background color. Fill the _rectangle_ on the canvas
-      covered by the _current frame_ with background color specified in the
-      [ANIM chunk](#anim_chunk).
+    * `1`: Dispose to the background color. Fill the _rectangle_ on the canvas
+      covered by the _current frame_ with the background color specified in the
+      ['ANIM' Chunk](#anim_chunk).
 
 **Notes**:
 
   * The frame disposal only applies to the _frame rectangle_, that is, the
-    rectangle defined by _Frame X_, _Frame Y_, _frame width_ and _frame height_.
-    It may or may not cover the whole canvas.
+    rectangle defined by _Frame X_, _Frame Y_, _frame width_, and _frame
+    height_. It may or may not cover the whole canvas.
 
 {:#alpha-blending}
-  * **Alpha-blending**:
+  * Alpha-blending:
 
-    Given that each of the R, G, B and A channels is 8-bit, and the RGB
+    Given that each of the R, G, B, and A channels is 8 bits, and the RGB
     channels are _not premultiplied_ by alpha, the formula for blending
     'dst' onto 'src' is:
 
@@ -493,16 +515,17 @@ Disposal method (D): 1 bit
     if blend.A = 0 then
       blend.RGB = 0
     else
-      blend.RGB = (src.RGB * src.A +
-                   dst.RGB * dst.A * (1 - src.A / 255)) / blend.A
+      blend.RGB =
+          (src.RGB * src.A +
+           dst.RGB * dst.A * (1 - src.A / 255)) / blend.A
 ~~~~~
 
   * Alpha-blending SHOULD be done in linear color space, by taking into account
     the [color profile](#color-profile) of the image. If the color profile is
-    not present, sRGB is to be assumed. (Note that sRGB also needs to be
-    linearized due to a gamma of ~2.2).
+    not present, standard RGB (sRGB) is to be assumed. (Note that sRGB also
+    needs to be linearized due to a gamma of ~2.2.)
 
-Frame Data: _Chunk Size_ - `16` bytes
+Frame Data: _Chunk Size_ bytes - `16`
 
 : Consists of:
 
@@ -512,8 +535,8 @@ Frame Data: _Chunk Size_ - `16` bytes
 
   * An optional list of [unknown chunks](#unknown-chunks).
 
-**Note**: The 'ANMF' payload, _Frame Data_ above, consists of individual
-_padded_ chunks as described by the [RIFF file format](#riff-file-format).
+**Note**: The 'ANMF' payload, _Frame Data_, consists of individual
+_padded_ chunks, as described by the [RIFF file format](#riff-file-format).
 
 #### Alpha
 
@@ -521,26 +544,29 @@ _padded_ chunks as described by the [RIFF file format](#riff-file-format).
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('ALPH')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Rsv| P | F | C |     Alpha Bitstream...                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
 Reserved (Rsv): 2 bits
 
-: SHOULD be `0`.
+: MUST be `0`. Readers MUST ignore this field.
 
-Pre-processing (P): 2 bits
+Preprocessing (P): 2 bits
 
-: These INFORMATIVE bits are used to signal the pre-processing that has
+: These _informative_ bits are used to signal the preprocessing that has
   been performed during compression. The decoder can use this information to
-  e.g. dither the values or smooth the gradients prior to display.
+  for example, dither the values or smooth the gradients prior to display.
 
-    * `0`: no pre-processing
-    * `1`: level reduction
+    * `0`: No preprocessing.
+    * `1`: Level reduction.
+
+Decoders are not required to use this information in any specified way.
 
 Filtering method (F): 2 bits
 
-: The filtering method used:
+: The filtering methods used are described as follows:
 
     * `0`: None.
     * `1`: Horizontal filter.
@@ -564,27 +590,25 @@ made depending on the filtering method:
 
 where `clip(v)` is equal to:
 
-  * 0    if v < 0
-  * 255  if v > 255
+  * 0    if v < 0,
+  * 255  if v > 255, or
   * v    otherwise
 
 The final value is derived by adding the decompressed value `X` to the
-predictor and using modulo-256 arithmetic to wrap the \[256-511\] range
-into the \[0-255\] one:
+predictor and using modulo-256 arithmetic to wrap the \[256..511\] range
+into the \[0..255\] one:
 
 `alpha = (predictor + X) % 256`
 
-There are special cases for left-most and top-most pixel positions:
+There are special cases for the left-most and top-most pixel positions. For
+example, the top-left value at location (0, 0) uses 0 as the predictor value.
+Otherwise:
 
-  * Top-left value at location (0,0) uses 0 as predictor value. Otherwise,
   * For horizontal or gradient filtering methods, the left-most pixels at
     location (0, y) are predicted using the location (0, y-1) just above.
   * For vertical or gradient filtering methods, the top-most pixels at
     location (x, 0) are predicted using the location (x-1, 0) on the left.
 
-
-Decoders are not required to use this information in any specified way.
-
 Compression method (C): 2 bits
 
 : The compression method used:
@@ -592,37 +616,37 @@ Compression method (C): 2 bits
     * `0`: No compression.
     * `1`: Compressed using the WebP lossless format.
 
-Alpha bitstream: _Chunk Size_ - `1` bytes
+Alpha bitstream: _Chunk Size_ bytes - `1`
 
 : Encoded alpha bitstream.
 
 This optional chunk contains encoded alpha data for this frame. A frame
-containing a 'VP8L' chunk SHOULD NOT contain this chunk.
+containing a 'VP8L' Chunk SHOULD NOT contain this chunk.
 
 **Rationale**: The transparency information is already part of the 'VP8L'
-chunk.
+Chunk.
 
-The alpha channel data is stored as uncompressed raw data (when
+The alpha channel data is stored as uncompressed raw data (when the
 compression method is '0') or compressed using the lossless format
 (when the compression method is '1').
 
-  * Raw data: consists of a byte sequence of length width * height,
+  * Raw data: This consists of a byte sequence of length = width * height,
     containing all the 8-bit transparency values in scan order.
 
-  * Lossless format compression: the byte sequence is a compressed
-    image-stream (as described in the [WebP Lossless Bitstream Format]
-    [webpllspec]) of implicit dimension width x height. That is, this
-    image-stream does NOT contain any headers describing the image dimension.
+  * Lossless format compression: The byte sequence is a compressed
+    image-stream (as described in ["WebP Lossless Bitstream Format"]
+    [webpllspec]) of implicit dimensions width x height. That is, this
+    image-stream does NOT contain any headers describing the image dimensions.
 
-    **Rationale**: the dimension is already known from other sources,
-    so storing it again would be redundant and error-prone.
+    **Rationale**: The dimensions are already known from other sources,
+    so storing them again would be redundant and prone to error.
 
-    Once the image-stream is decoded into ARGB color values, following
-    the process described in the lossless format specification, the
-    transparency information must be extracted from the *green* channel
-    of the ARGB quadruplet.
+    Once the image-stream is decoded into Alpha, Red, Green, Blue (ARGB) color
+    values, following the process described in the lossless format
+    specification, the transparency information must be extracted from the
+    *green* channel of the ARGB quadruplet.
 
-    **Rationale**: the green channel is allowed extra transformation
+    **Rationale**: The green channel is allowed extra transformation
     steps in the specification -- unlike the other channels -- that can
     improve compression.
 
@@ -630,22 +654,23 @@ compression method is '0') or compressed using the lossless format
 
 This chunk contains compressed bitstream data for a single frame.
 
-A bitstream chunk may be either (i) a VP8 chunk, using "VP8 " (note the
-significant fourth-character space) as its tag _or_ (ii) a VP8L chunk, using
-"VP8L" as its tag.
+A bitstream chunk may be either (i) a 'VP8 ' Chunk, using 'VP8 ' (note the
+significant fourth-character space) as its FourCC, _or_ (ii) a 'VP8L' Chunk,
+using 'VP8L' as its FourCC.
 
-The formats of VP8 and VP8L chunks are as described in sections
+The formats of 'VP8 ' and 'VP8L' Chunks are as described in sections
 [Simple File Format (Lossy)](#simple-file-format-lossy)
-and [Simple File Format (Lossless)](#simple-file-format-lossless) respectively.
+and [Simple File Format (Lossless)](#simple-file-format-lossless), respectively.
 
-#### Color profile
+#### Color Profile
 
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('ICCP')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                       Color Profile                           |
+    :                       Color Profile                           :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
 Color Profile: _Chunk Size_ bytes
@@ -662,114 +687,145 @@ If this chunk is not present, sRGB SHOULD be assumed.
 
 #### Metadata
 
-Metadata can be stored in 'EXIF' or 'XMP ' chunks.
+Metadata can be stored in 'EXIF' or 'XMP ' Chunks.
 
 There SHOULD be at most one chunk of each type ('EXIF' and 'XMP '). If there
-are more such chunks, readers MAY ignore all except the first one. Also, a file
-may possibly contain both 'EXIF' and 'XMP ' chunks.
+are more such chunks, readers MAY ignore all except the first one.
 
 The chunks are defined as follows:
 
-EXIF chunk:
+'EXIF' Chunk:
 
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('EXIF')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                        EXIF Metadata                          |
+    :                        Exif Metadata                          :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
-EXIF Metadata: _Chunk Size_ bytes
+Exif Metadata: _Chunk Size_ bytes
 
-: image metadata in EXIF format.
+: Image metadata in Exif format.
 
-XMP chunk:
+'XMP ' Chunk:
 
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                      ChunkHeader('XMP ')                      |
+    |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                        XMP Metadata                           |
+    :                        XMP Metadata                           :
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
 XMP Metadata: _Chunk Size_ bytes
 
-: image metadata in XMP format.
+: Image metadata in XMP format.
+
+Note that the fourth character in the 'XMP ' FourCC is an ASCII space (0x20).
 
 Additional guidance about handling metadata can be found in the
-Metadata Working Group's [Guidelines for Handling Metadata][metadata].
+Metadata Working Group's ["Guidelines for Handling Metadata"][metadata].
 
 #### Unknown Chunks
 
-A RIFF chunk (described in [this](#terminology-amp-basics) section) whose _chunk
-tag_ is different from any of the chunks described in this document, is
+A RIFF chunk (described in the [RIFF File Format](#riff-file-format) section)
+whose FourCC is different from any of the chunks described in this document, is
 considered an _unknown chunk_.
 
 **Rationale**: Allowing unknown chunks gives a provision for future extension
-of the format, and also allows storage of any application-specific data.
+of the format and also allows storage of any application-specific data.
 
 A file MAY contain unknown chunks:
 
-  * At the end of the file as described in [Extended WebP file
-    header](#extended_header) section.
-  * At the end of ANMF chunks as described in the
+  * at the end of the file, as described in [Extended WebP file
+    header](#extended_header) section, or
+  * at the end of 'ANMF' Chunks, as described in the
     [Animation](#animation) section.
 
 Readers SHOULD ignore these chunks. Writers SHOULD preserve them in their
 original order (unless they specifically intend to modify these chunks).
 
-### Assembling the Canvas from frames
+### Canvas Assembly from Frames
 
-Here we provide an overview of how a reader should assemble a canvas in the
-case of an animated image. The notation _VP8X.field_ means the field in the
-'VP8X' chunk with the same description.
+Here we provide an overview of how a reader MUST assemble a canvas in the case
+of an animated image.
 
-Displaying an _animated image_ canvas MUST be equivalent to the following
-pseudocode:
+The process begins with creating a canvas using the dimensions given in the
+'VP8X' Chunk, `Canvas Width Minus One + 1` pixels wide by `Canvas Height Minus
+One + 1` pixels high. The `Loop Count` field from the 'ANIM' Chunk controls how
+many times the animation process is repeated. This is `Loop Count - 1` for
+nonzero `Loop Count` values or infinite if the `Loop Count` is zero.
+
+At the beginning of each loop iteration, the canvas is filled using the
+background color from the 'ANIM' Chunk or an application-defined color.
+
+'ANMF' Chunks contain individual frames given in display order. Before rendering
+each frame, the previous frame's `Disposal method` is applied.
+
+The rendering of the decoded frame begins at the Cartesian coordinates (`2 *
+Frame X`, `2 * Frame Y`), using the top-left corner of the canvas as the origin.
+`Frame Width Minus One + 1` pixels wide by `Frame Height Minus One + 1` pixels
+high are rendered onto the canvas using the `Blending method`.
+
+The canvas is displayed for `Frame Duration` milliseconds. This continues until
+all frames given by 'ANMF' Chunks have been displayed. A new loop iteration is
+then begun, or the canvas is left in its final state if all iterations have been
+completed.
+
+The following pseudocode illustrates the rendering process. The notation
+_VP8X.field_ means the field in the 'VP8X' Chunk with the same description.
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-assert VP8X.flags.hasAnimation
+VP8X.flags.hasAnimation MUST be TRUE
 canvas ← new image of size VP8X.canvasWidth x VP8X.canvasHeight with
-         background color ANIM.background_color.
+         background color ANIM.background_color or
+         application-defined color.
 loop_count ← ANIM.loopCount
-dispose_method ← ANIM.disposeMethod
+dispose_method ← Dispose to background color
 if loop_count == 0:
-    loop_count = ∞
+  loop_count = ∞
 frame_params ← nil
-assert next chunk in image_data is ANMF
+next chunk in image_data is ANMF MUST be TRUE
 for loop = 0..loop_count - 1
-    clear canvas to ANIM.background_color or application defined color
-    until eof or non-ANMF chunk
-        frame_params.frameX = Frame X
-        frame_params.frameY = Frame Y
-        frame_params.frameWidth = Frame Width Minus One + 1
-        frame_params.frameHeight = Frame Height Minus One + 1
-        frame_params.frameDuration = Frame Duration
-        frame_right = frame_params.frameX + frame_params.frameWidth
-        frame_bottom = frame_params.frameY + frame_params.frameHeight
-        assert VP8X.canvasWidth >= frame_right
-        assert VP8X.canvasHeight >= frame_bottom
-        for subchunk in 'Frame Data':
-            if subchunk.tag == "ALPH":
-                assert alpha subchunks not found in 'Frame Data' earlier
-                frame_params.alpha = alpha_data
-            else if subchunk.tag == "VP8 " OR subchunk.tag == "VP8L":
-                assert bitstream subchunks not found in 'Frame Data' earlier
-                frame_params.bitstream = bitstream_data
-        render frame with frame_params.alpha and frame_params.bitstream on
-            canvas with top-left corner at (frame_params.frameX,
-            frame_params.frameY), using dispose method dispose_method.
-        canvas contains the decoded image.
-        Show the contents of the canvas for frame_params.frameDuration * 1ms.
+  clear canvas to ANIM.background_color or application-defined color
+  until eof or non-ANMF chunk
+    frame_params.frameX = Frame X
+    frame_params.frameY = Frame Y
+    frame_params.frameWidth = Frame Width Minus One + 1
+    frame_params.frameHeight = Frame Height Minus One + 1
+    frame_params.frameDuration = Frame Duration
+    frame_right = frame_params.frameX + frame_params.frameWidth
+    frame_bottom = frame_params.frameY + frame_params.frameHeight
+    VP8X.canvasWidth >= frame_right MUST be TRUE
+    VP8X.canvasHeight >= frame_bottom MUST be TRUE
+    for subchunk in 'Frame Data':
+      if subchunk.tag == "ALPH":
+        alpha subchunks not found in 'Frame Data' earlier MUST be
+          TRUE
+        frame_params.alpha = alpha_data
+      else if subchunk.tag == "VP8 " OR subchunk.tag == "VP8L":
+        bitstream subchunks not found in 'Frame Data' earlier MUST
+          be TRUE
+        frame_params.bitstream = bitstream_data
+    apply dispose_method.
+    render frame with frame_params.alpha and frame_params.bitstream
+      on canvas with top-left corner at (frame_params.frameX,
+      frame_params.frameY), using Blending method
+      frame_params.blendingMethod.
+    canvas contains the decoded image.
+    Show the contents of the canvas for
+    frame_params.frameDuration * 1 ms.
+    dispose_method = frame_params.disposeMethod
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Example File Layouts
 --------------------
 
-A lossy encoded image with alpha may look as follows:
+A lossy-encoded image with alpha may look as follows:
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 RIFF/WEBP
@@ -778,16 +834,16 @@ RIFF/WEBP
 +- VP8 (bitstream)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-A losslessly encoded image may look as follows:
+A lossless-encoded image may look as follows:
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 RIFF/WEBP
 +- VP8X (descriptions of features used)
-+- XYZW (unknown chunk)
 +- VP8L (lossless bitstream)
++- XYZW (unknown chunk)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-A lossless image with ICC profile and XMP metadata may
+A lossless image with an ICC profile and XMP metadata may
 look as follows:
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -798,7 +854,7 @@ RIFF/WEBP
 +- XMP  (metadata)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-An animated image with EXIF metadata may look as follows:
+An animated image with Exif metadata may look as follows:
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 RIFF/WEBP
@@ -811,9 +867,11 @@ RIFF/WEBP
 +- EXIF (metadata)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-[vp8spec]:  https://datatracker.ietf.org/doc/html/rfc6386
 [webpllspec]: https://chromium.googlesource.com/webm/libwebp/+/HEAD/doc/webp-lossless-bitstream-spec.txt
 [iccspec]: https://www.color.org/icc_specs2.xalter
 [metadata]: https://web.archive.org/web/20180919181934/http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf
+[rec601]: https://www.itu.int/rec/R-REC-BT.601
 [rfc 1166]: https://datatracker.ietf.org/doc/html/rfc1166
 [rfc 2119]: https://datatracker.ietf.org/doc/html/rfc2119
+[rfc 6386]: https://datatracker.ietf.org/doc/html/rfc6386
+[rfc 8174]: https://datatracker.ietf.org/doc/html/rfc8174

examples/Android.mk

@@ -1,3 +1,5 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
 LOCAL_PATH := $(call my-dir)
 
 ################################################################################
@@ -91,3 +93,4 @@ LOCAL_STATIC_LIBRARIES := example_util imageio_util webp
 LOCAL_MODULE := webpinfo_example
 
 include $(BUILD_EXECUTABLE)
+endif  # NDK_ROOT

examples/Makefile.am

@@ -47,7 +47,7 @@ anim_dump_LDADD += ../imageio/libimageenc.la
 anim_dump_LDADD += $(PNG_LIBS) $(GIF_LIBS) $(TIFF_LIBS) -lm
 
 cwebp_SOURCES  = cwebp.c stopwatch.h
-cwebp_CPPFLAGS  = $(AM_CPPFLAGS)
+cwebp_CPPFLAGS  = $(AM_CPPFLAGS) -I$(top_srcdir)
 cwebp_LDADD  =
 cwebp_LDADD += libexample_util.la
 cwebp_LDADD += ../imageio/libimageio_util.la
@@ -92,7 +92,7 @@ webpmux_LDADD += ../src/mux/libwebpmux.la
 webpmux_LDADD += ../src/libwebp.la
 
 img2webp_SOURCES = img2webp.c
-img2webp_CPPFLAGS = $(AM_CPPFLAGS)
+img2webp_CPPFLAGS = $(AM_CPPFLAGS) -I$(top_srcdir)
 img2webp_LDADD  =
 img2webp_LDADD += libexample_util.la
 img2webp_LDADD += ../imageio/libimageio_util.la

examples/anim_diff.c

@@ -16,7 +16,7 @@
 #include <assert.h>
 #include <limits.h>
 #include <stdio.h>
-#include <stdlib.h>  // for 'strtod'.
+#include <stdlib.h>
 #include <string.h>  // for 'strcmp'.
 
 #include "./anim_util.h"
@@ -206,8 +206,9 @@ static void Help(void) {
   printf("  -version ............ print version number and exit\n");
 }
 
+// Returns 0 on success, 1 if animation files differ, and 2 for any error.
 int main(int argc, const char* argv[]) {
-  int return_code = -1;
+  int return_code = 2;
   int dump_frames = 0;
   const char* dump_folder = NULL;
   double min_psnr = 0.;
@@ -269,18 +270,18 @@ int main(int argc, const char* argv[]) {
     }
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(return_code);
     }
   }
   if (argc < 3) {
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(return_code);
   }
 
 
   if (!got_input2) {
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(return_code);
   }
 
   if (dump_frames) {
@@ -293,7 +294,7 @@ int main(int argc, const char* argv[]) {
     if (!ReadAnimatedImage(files[i], &images[i], dump_frames, dump_folder)) {
       WFPRINTF(stderr, "Error decoding file: %s\n Aborting.\n",
                (const W_CHAR*)files[i]);
-      return_code = -2;
+      return_code = 2;
       goto End;
     } else {
       MinimizeAnimationFrames(&images[i], max_diff);
@@ -304,7 +305,7 @@ int main(int argc, const char* argv[]) {
                                 premultiply, min_psnr)) {
     WFPRINTF(stderr, "\nFiles %s and %s differ.\n", (const W_CHAR*)files[0],
              (const W_CHAR*)files[1]);
-    return_code = -3;
+    return_code = 1;
   } else {
     WPRINTF("\nFiles %s and %s are identical.\n", (const W_CHAR*)files[0],
             (const W_CHAR*)files[1]);

examples/anim_dump.c

@@ -12,6 +12,7 @@
 // Author: Skal (pascal.massimino@gmail.com)
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>  // for 'strcmp'.
 
 #include "./anim_util.h"
@@ -35,6 +36,7 @@ static void Help(void) {
   printf("  -version ............ print version number and exit\n");
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int error = 0;
   const W_CHAR* dump_folder = TO_W_CHAR(".");
@@ -47,7 +49,7 @@ int main(int argc, const char* argv[]) {
 
   if (argc < 2) {
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   for (c = 1; !error && c < argc; ++c) {
@@ -73,7 +75,7 @@ int main(int argc, const char* argv[]) {
       suffix = TO_W_CHAR("pam");
     } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-version")) {
       int dec_version, demux_version;
       GetAnimatedImageVersions(&dec_version, &demux_version);
@@ -82,7 +84,7 @@ int main(int argc, const char* argv[]) {
              (dec_version >> 0) & 0xff,
              (demux_version >> 16) & 0xff, (demux_version >> 8) & 0xff,
              (demux_version >> 0) & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {
       uint32_t i;
       AnimatedImage image;
@@ -98,7 +100,11 @@ int main(int argc, const char* argv[]) {
       for (i = 0; !error && i < image.num_frames; ++i) {
         W_CHAR out_file[1024];
         WebPDecBuffer buffer;
-        WebPInitDecBuffer(&buffer);
+        if (!WebPInitDecBuffer(&buffer)) {
+          fprintf(stderr, "Cannot init dec buffer\n");
+          error = 1;
+          continue;
+        }
         buffer.colorspace = MODE_RGBA;
         buffer.is_external_memory = 1;
         buffer.width = image.canvas_width;
@@ -117,5 +123,5 @@ int main(int argc, const char* argv[]) {
       ClearAnimatedImage(&image);
     }
   }
-  FREE_WARGV_AND_RETURN(error ? 1 : 0);
+  FREE_WARGV_AND_RETURN(error ? EXIT_FAILURE : EXIT_SUCCESS);
 }

examples/anim_util.c

@@ -241,7 +241,7 @@ static int ReadAnimatedWebP(const char filename[],
   image->bgcolor = anim_info.bgcolor;
 
   // Allocate frames.
-  if (!AllocateFrames(image, anim_info.frame_count)) return 0;
+  if (!AllocateFrames(image, anim_info.frame_count)) goto End;
 
   // Decode frames.
   while (WebPAnimDecoderHasMoreFrames(dec)) {
@@ -558,7 +558,10 @@ static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
     }
   }
   // Allocate frames.
-  AllocateFrames(image, frame_count);
+  if (!AllocateFrames(image, frame_count)) {
+    DGifCloseFile(gif, NULL);
+    return 0;
+  }
 
   canvas_width = image->canvas_width;
   canvas_height = image->canvas_height;

examples/cwebp.c

@@ -27,6 +27,7 @@
 #include "../imageio/webpdec.h"
 #include "./stopwatch.h"
 #include "./unicode.h"
+#include "sharpyuv/sharpyuv.h"
 #include "webp/encode.h"
 
 #ifndef WEBP_DLL
@@ -177,8 +178,14 @@ static void PrintFullLosslessInfo(const WebPAuxStats* const stats,
     if (stats->lossless_features & 8) fprintf(stderr, " PALETTE");
     fprintf(stderr, "\n");
   }
-  fprintf(stderr, "  * Precision Bits: histogram=%d transform=%d cache=%d\n",
-          stats->histogram_bits, stats->transform_bits, stats->cache_bits);
+  fprintf(stderr, "  * Precision Bits: histogram=%d", stats->histogram_bits);
+  if (stats->lossless_features & 1) {
+    fprintf(stderr, " prediction=%d", stats->transform_bits);
+  }
+  if (stats->lossless_features & 2) {
+    fprintf(stderr, " cross-color=%d", stats->cross_color_transform_bits);
+  }
+  fprintf(stderr, " cache=%d\n", stats->cache_bits);
   if (stats->palette_size > 0) {
     fprintf(stderr, "  * Palette size:   %d\n", stats->palette_size);
   }
@@ -305,6 +312,7 @@ static int MyWriter(const uint8_t* data, size_t data_size,
 // Dumps a picture as a PGM file using the IMC4 layout.
 static int DumpPicture(const WebPPicture* const picture, const char* PGM_name) {
   int y;
+  int ok = 0;
   const int uv_width = (picture->width + 1) / 2;
   const int uv_height = (picture->height + 1) / 2;
   const int stride = (picture->width + 1) & ~1;
@@ -319,23 +327,26 @@ static int DumpPicture(const WebPPicture* const picture, const char* PGM_name) {
   if (f == NULL) return 0;
   fprintf(f, "P5\n%d %d\n255\n", stride, height);
   for (y = 0; y < picture->height; ++y) {
-    if (fwrite(src_y, picture->width, 1, f) != 1) return 0;
+    if (fwrite(src_y, picture->width, 1, f) != 1) goto Error;
     if (picture->width & 1) fputc(0, f);  // pad
     src_y += picture->y_stride;
   }
   for (y = 0; y < uv_height; ++y) {
-    if (fwrite(src_u, uv_width, 1, f) != 1) return 0;
-    if (fwrite(src_v, uv_width, 1, f) != 1) return 0;
+    if (fwrite(src_u, uv_width, 1, f) != 1) goto Error;
+    if (fwrite(src_v, uv_width, 1, f) != 1) goto Error;
     src_u += picture->uv_stride;
     src_v += picture->uv_stride;
   }
   for (y = 0; y < alpha_height; ++y) {
-    if (fwrite(src_a, picture->width, 1, f) != 1) return 0;
+    if (fwrite(src_a, picture->width, 1, f) != 1) goto Error;
     if (picture->width & 1) fputc(0, f);  // pad
     src_a += picture->a_stride;
   }
+  ok = 1;
+
+ Error:
   fclose(f);
-  return 1;
+  return ok;
 }
 
 // -----------------------------------------------------------------------------
@@ -571,7 +582,7 @@ static void HelpLong(void) {
   printf("  -qrange <min> <max> .... specifies the permissible quality range\n"
          "                           (default: 0 100)\n");
   printf("  -crop <x> <y> <w> <h> .. crop picture with the given rectangle\n");
-  printf("  -resize <w> <h> ........ resize picture (after any cropping)\n");
+  printf("  -resize <w> <h> ........ resize picture (*after* any cropping)\n");
   printf("  -mt .................... use multi-threading if available\n");
   printf("  -low_memory ............ reduce memory usage (slower encoding)\n");
   printf("  -map <int> ............. print map of extra info\n");
@@ -591,9 +602,8 @@ static void HelpLong(void) {
          "                           green=0xe0 and blue=0xd0\n");
   printf("  -noalpha ............... discard any transparency information\n");
   printf("  -lossless .............. encode image losslessly, default=off\n");
-  printf("  -near_lossless <int> ... use near-lossless image\n"
-         "                           preprocessing (0..100=off), "
-         "default=100\n");
+  printf("  -near_lossless <int> ... use near-lossless image preprocessing\n"
+         "                           (0..100=off), default=100\n");
   printf("  -hint <string> ......... specify image characteristics hint,\n");
   printf("                           one of: photo, picture or graph\n");
 
@@ -620,6 +630,7 @@ static void HelpLong(void) {
   printf("  -af .................... auto-adjust filter strength\n");
   printf("  -pre <int> ............. pre-processing filter\n");
   printf("\n");
+  printf("Supported input formats:\n  %s\n", WebPGetEnabledInputFileFormats());
 }
 
 //------------------------------------------------------------------------------
@@ -646,8 +657,9 @@ static const char* const kErrorMessages[VP8_ENC_ERROR_LAST] = {
 
 //------------------------------------------------------------------------------
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
-  int return_value = -1;
+  int return_value = EXIT_FAILURE;
   const char* in_file = NULL, *out_file = NULL, *dump_file = NULL;
   FILE* out = NULL;
   int c;
@@ -681,22 +693,22 @@ int main(int argc, const char* argv[]) {
       !WebPPictureInit(&original_picture) ||
       !WebPConfigInit(&config)) {
     fprintf(stderr, "Error! Version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   if (argc == 1) {
     HelpShort();
-    FREE_WARGV_AND_RETURN(0);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   for (c = 1; c < argc; ++c) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       HelpShort();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-H") || !strcmp(argv[c], "-longhelp")) {
       HelpLong();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-o") && c + 1 < argc) {
       out_file = (const char*)GET_WARGV(argv, ++c);
     } else if (!strcmp(argv[c], "-d") && c + 1 < argc) {
@@ -831,9 +843,13 @@ int main(int argc, const char* argv[]) {
 #endif
     } else if (!strcmp(argv[c], "-version")) {
       const int version = WebPGetEncoderVersion();
+      const int sharpyuv_version = SharpYuvGetVersion();
       printf("%d.%d.%d\n",
              (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      printf("libsharpyuv: %d.%d.%d\n",
+             (sharpyuv_version >> 24) & 0xff, (sharpyuv_version >> 16) & 0xffff,
+             sharpyuv_version & 0xff);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-progress")) {
       show_progress = 1;
     } else if (!strcmp(argv[c], "-quiet")) {
@@ -895,7 +911,7 @@ int main(int argc, const char* argv[]) {
         if (i == kNumTokens) {
           fprintf(stderr, "Error! Unknown metadata type '%.*s'\n",
                   (int)(token - start), start);
-          FREE_WARGV_AND_RETURN(-1);
+          FREE_WARGV_AND_RETURN(EXIT_FAILURE);
         }
         start = token + 1;
       }
@@ -914,14 +930,14 @@ int main(int argc, const char* argv[]) {
     } else if (argv[c][0] == '-') {
       fprintf(stderr, "Error! Unknown option '%s'\n", argv[c]);
       HelpLong();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       in_file = (const char*)GET_WARGV(argv, c);
     }
 
     if (parse_error) {
       HelpLong();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
   if (in_file == NULL) {
@@ -1139,9 +1155,10 @@ int main(int argc, const char* argv[]) {
       }
 
       picture.use_argb = 1;
-      if (!ReadWebP(memory_writer.mem, memory_writer.size, &picture,
-                    /*keep_alpha=*/WebPPictureHasTransparency(&picture),
-                    /*metadata=*/NULL)) {
+      if (!ReadWebP(
+              memory_writer.mem, memory_writer.size, &picture,
+              /*keep_alpha=*/WebPPictureHasTransparency(&original_picture),
+              /*metadata=*/NULL)) {
         fprintf(stderr, "Error! Cannot decode encoded WebP bitstream\n");
         fprintf(stderr, "Error code: %d (%s)\n", picture.error_code,
                 kErrorMessages[picture.error_code]);
@@ -1221,7 +1238,7 @@ int main(int argc, const char* argv[]) {
       PrintMetadataInfo(&metadata, metadata_written);
     }
   }
-  return_value = 0;
+  return_value = EXIT_SUCCESS;
 
  Error:
   WebPMemoryWriterClear(&memory_writer);

examples/dwebp.c

@@ -96,7 +96,7 @@ static void Help(void) {
          "  -alpha_dither  use alpha-plane dithering if needed\n"
          "  -mt .......... use multi-threading\n"
          "  -crop <x> <y> <w> <h> ... crop output with the given rectangle\n"
-         "  -resize <w> <h> ......... scale the output (*after* any cropping)\n"
+         "  -resize <w> <h> ......... resize output (*after* any cropping)\n"
          "  -flip ........ flip the output vertically\n"
          "  -alpha ....... only save the alpha plane\n"
          "  -incremental . use incremental decoding (useful for tests)\n"
@@ -177,6 +177,7 @@ static uint8_t* AllocateExternalBuffer(WebPDecoderConfig* config,
   return external_buffer;
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int ok = 0;
   const char* in_file = NULL;
@@ -197,14 +198,14 @@ int main(int argc, const char* argv[]) {
 
   if (!WebPInitDecoderConfig(&config)) {
     fprintf(stderr, "Library version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   for (c = 1; c < argc; ++c) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
       out_file = (const char*)GET_WARGV(argv, ++c);
     } else if (!strcmp(argv[c], "-alpha")) {
@@ -227,7 +228,7 @@ int main(int argc, const char* argv[]) {
       const int version = WebPGetDecoderVersion();
       printf("%d.%d.%d\n",
              (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-pgm")) {
       format = PGM;
     } else if (!strcmp(argv[c], "-yuv")) {
@@ -293,21 +294,21 @@ int main(int argc, const char* argv[]) {
     } else if (argv[c][0] == '-') {
       fprintf(stderr, "Unknown option '%s'\n", argv[c]);
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       in_file = (const char*)GET_WARGV(argv, c);
     }
 
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
 
   if (in_file == NULL) {
     fprintf(stderr, "missing input file!!\n");
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   if (quiet) verbose = 0;
@@ -316,7 +317,7 @@ int main(int argc, const char* argv[]) {
     VP8StatusCode status = VP8_STATUS_OK;
     size_t data_size = 0;
     if (!LoadWebP(in_file, &data, &data_size, bitstream)) {
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
 
     switch (format) {
@@ -415,7 +416,7 @@ int main(int argc, const char* argv[]) {
   WebPFreeDecBuffer(output_buffer);
   WebPFree((void*)external_buffer);
   WebPFree((void*)data);
-  FREE_WARGV_AND_RETURN(ok ? 0 : -1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 //------------------------------------------------------------------------------

examples/example_util.c

@@ -103,7 +103,10 @@ int ExUtilInitCommandLineArguments(int argc, const char* argv[],
     }
     args->own_argv_ = 1;
     args->argv_ = (const char**)WebPMalloc(MAX_ARGC * sizeof(*args->argv_));
-    if (args->argv_ == NULL) return 0;
+    if (args->argv_ == NULL) {
+      ExUtilDeleteCommandLineArguments(args);
+      return 0;
+    }
 
     argc = 0;
     for (cur = strtok((char*)args->argv_data_.bytes, sep);
@@ -111,6 +114,7 @@ int ExUtilInitCommandLineArguments(int argc, const char* argv[],
          cur = strtok(NULL, sep)) {
       if (argc == MAX_ARGC) {
         fprintf(stderr, "ERROR: Arguments limit %d reached\n", MAX_ARGC);
+        ExUtilDeleteCommandLineArguments(args);
         return 0;
       }
       assert(strlen(cur) != 0);

examples/gif2webp.c

@@ -96,6 +96,7 @@ static void Help(void) {
 
 //------------------------------------------------------------------------------
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int verbose = 0;
   int gif_error = GIF_ERROR;
@@ -140,7 +141,7 @@ int main(int argc, const char* argv[]) {
       !WebPPictureInit(&frame) || !WebPPictureInit(&curr_canvas) ||
       !WebPPictureInit(&prev_canvas)) {
     fprintf(stderr, "Error! Version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
   config.lossless = 1;  // Use lossless compression by default.
 
@@ -150,14 +151,14 @@ int main(int argc, const char* argv[]) {
 
   if (argc == 1) {
     Help();
-    FREE_WARGV_AND_RETURN(0);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   for (c = 1; c < argc; ++c) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
       out_file = GET_WARGV(argv, ++c);
     } else if (!strcmp(argv[c], "-lossy")) {
@@ -216,7 +217,7 @@ int main(int argc, const char* argv[]) {
           fprintf(stderr, "Error! Unknown metadata type '%.*s'\n",
                   (int)(token - start), start);
           Help();
-          FREE_WARGV_AND_RETURN(-1);
+          FREE_WARGV_AND_RETURN(EXIT_FAILURE);
         }
         start = token + 1;
       }
@@ -229,7 +230,7 @@ int main(int argc, const char* argv[]) {
              (enc_version >> 16) & 0xff, (enc_version >> 8) & 0xff,
              enc_version & 0xff, (mux_version >> 16) & 0xff,
              (mux_version >> 8) & 0xff, mux_version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-quiet")) {
       quiet = 1;
       enc_options.verbose = 0;
@@ -242,14 +243,14 @@ int main(int argc, const char* argv[]) {
     } else if (argv[c][0] == '-') {
       fprintf(stderr, "Error! Unknown option '%s'\n", argv[c]);
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       in_file = GET_WARGV(argv, c);
     }
 
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
 
@@ -314,8 +315,11 @@ int main(int argc, const char* argv[]) {
           frame.use_argb = 1;
           if (!WebPPictureAlloc(&frame)) goto End;
           GIFClearPic(&frame, NULL);
-          WebPPictureCopy(&frame, &curr_canvas);
-          WebPPictureCopy(&frame, &prev_canvas);
+          if (!(WebPPictureCopy(&frame, &curr_canvas) &&
+                WebPPictureCopy(&frame, &prev_canvas))) {
+            fprintf(stderr, "Error allocating canvas.\n");
+            goto End;
+          }
 
           // Background color.
           GIFGetBackgroundColor(gif->SColorMap, gif->SBackGroundColor,
@@ -590,7 +594,7 @@ int main(int argc, const char* argv[]) {
 #endif
   }
 
-  FREE_WARGV_AND_RETURN(!ok);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 #else  // !WEBP_HAVE_GIF
@@ -598,7 +602,7 @@ int main(int argc, const char* argv[]) {
 int main(int argc, const char* argv[]) {
   fprintf(stderr, "GIF support not enabled in %s.\n", argv[0]);
   (void)argc;
-  return 0;
+  return EXIT_FAILURE;
 }
 
 #endif

examples/gifdec.c

@@ -317,7 +317,7 @@ void GIFDisplayError(const GifFileType* const gif, int gif_error) {
 
 #else  // !WEBP_HAVE_GIF
 
-static void ErrorGIFNotAvailable() {
+static void ErrorGIFNotAvailable(void) {
   fprintf(stderr, "GIF support not compiled. Please install the libgif-dev "
           "package before building.\n");
 }

examples/img2webp.c

@@ -28,6 +28,7 @@
 #include "../imageio/imageio_util.h"
 #include "./stopwatch.h"
 #include "./unicode.h"
+#include "sharpyuv/sharpyuv.h"
 #include "webp/encode.h"
 #include "webp/mux.h"
 
@@ -35,17 +36,22 @@
 
 static void Help(void) {
   printf("Usage:\n\n");
-  printf("  img2webp [file_options] [[frame_options] frame_file]...\n");
-  printf("\n");
+  printf("  img2webp [file_options] [[frame_options] frame_file]...");
+  printf(" [-o webp_file]\n\n");
 
   printf("File-level options (only used at the start of compression):\n");
   printf(" -min_size ............ minimize size\n");
-  printf(" -loop <int> .......... loop count (default: 0, = infinite loop)\n");
   printf(" -kmax <int> .......... maximum number of frame between key-frames\n"
          "                        (0=only keyframes)\n");
   printf(" -kmin <int> .......... minimum number of frame between key-frames\n"
          "                        (0=disable key-frames altogether)\n");
   printf(" -mixed ............... use mixed lossy/lossless automatic mode\n");
+  printf(" -near_lossless <int> . use near-lossless image preprocessing\n"
+         "                        (0..100=off), default=100\n");
+  printf(" -sharp_yuv ........... use sharper (and slower) RGB->YUV "
+                                  "conversion\n                        "
+                                  "(lossy only)\n");
+  printf(" -loop <int> .......... loop count (default: 0, = infinite loop)\n");
   printf(" -v ................... verbose mode\n");
   printf(" -h ................... this help\n");
   printf(" -version ............. print version number and exit\n");
@@ -53,10 +59,14 @@ static void Help(void) {
 
   printf("Per-frame options (only used for subsequent images input):\n");
   printf(" -d <int> ............. frame duration in ms (default: 100)\n");
-  printf(" -lossless  ........... use lossless mode (default)\n");
-  printf(" -lossy ... ........... use lossy mode\n");
+  printf(" -lossless ............ use lossless mode (default)\n");
+  printf(" -lossy ............... use lossy mode\n");
   printf(" -q <float> ........... quality\n");
   printf(" -m <int> ............. method to use\n");
+  printf(" -exact, -noexact ..... preserve or alter RGB values in transparent "
+                                  "area\n"
+         "                        (default: -noexact, may cause artifacts\n"
+         "                                  with lossy animations)\n");
 
   printf("\n");
   printf("example: img2webp -loop 2 in0.png -lossy in1.jpg\n"
@@ -65,6 +75,8 @@ static void Help(void) {
          "arguments will be\n");
   printf("tokenized from this file. The file name must not start with "
          "the character '-'.\n");
+  printf("\nSupported input formats:\n  %s\n",
+         WebPGetEnabledInputFileFormats());
 }
 
 //------------------------------------------------------------------------------
@@ -122,6 +134,7 @@ static int SetLoopCount(int loop_count, WebPData* const webp_data) {
 
 //------------------------------------------------------------------------------
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   const char* output = NULL;
   WebPAnimEncoder* enc = NULL;
@@ -143,7 +156,7 @@ int main(int argc, const char* argv[]) {
   INIT_WARGV(argc, argv);
 
   ok = ExUtilInitCommandLineArguments(argc - 1, argv + 1, &cmd_args);
-  if (!ok) FREE_WARGV_AND_RETURN(1);
+  if (!ok) FREE_WARGV_AND_RETURN(EXIT_FAILURE);
 
   argc = cmd_args.argc_;
   argv = cmd_args.argv_;
@@ -182,18 +195,26 @@ int main(int argc, const char* argv[]) {
       } else if (!strcmp(argv[c], "-mixed")) {
         anim_config.allow_mixed = 1;
         config.lossless = 0;
+      } else if (!strcmp(argv[c], "-near_lossless") && c + 1 < argc) {
+        argv[c] = NULL;
+        config.near_lossless = ExUtilGetInt(argv[++c], 0, &parse_error);
+      } else if (!strcmp(argv[c], "-sharp_yuv")) {
+        config.use_sharp_yuv = 1;
       } else if (!strcmp(argv[c], "-v")) {
         verbose = 1;
       } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
         Help();
-        goto End;
+        FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
       } else if (!strcmp(argv[c], "-version")) {
         const int enc_version = WebPGetEncoderVersion();
         const int mux_version = WebPGetMuxVersion();
+        const int sharpyuv_version = SharpYuvGetVersion();
         printf("WebP Encoder version: %d.%d.%d\nWebP Mux version: %d.%d.%d\n",
                (enc_version >> 16) & 0xff, (enc_version >> 8) & 0xff,
                enc_version & 0xff, (mux_version >> 16) & 0xff,
                (mux_version >> 8) & 0xff, mux_version & 0xff);
+        printf("libsharpyuv: %d.%d.%d\n", (sharpyuv_version >> 24) & 0xff,
+               (sharpyuv_version >> 16) & 0xffff, sharpyuv_version & 0xff);
         goto End;
       } else {
         continue;
@@ -231,6 +252,10 @@ int main(int argc, const char* argv[]) {
           fprintf(stderr, "Invalid negative duration (%d)\n", duration);
           parse_error = 1;
         }
+      } else if (!strcmp(argv[c], "-exact")) {
+        config.exact = 1;
+      } else if (!strcmp(argv[c], "-noexact")) {
+        config.exact = 0;
       } else {
         parse_error = 1;   // shouldn't be here.
         fprintf(stderr, "Unknown option [%s]\n", argv[c]);
@@ -319,5 +344,5 @@ int main(int argc, const char* argv[]) {
   }
   WebPDataClear(&webp_data);
   ExUtilDeleteCommandLineArguments(&cmd_args);
-  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }

examples/unicode.h

@@ -16,11 +16,15 @@
 #ifndef WEBP_EXAMPLES_UNICODE_H_
 #define WEBP_EXAMPLES_UNICODE_H_
 
+#include <stdio.h>
+
 #if defined(_WIN32) && defined(_UNICODE)
 
 // wchar_t is used instead of TCHAR because we only perform additional work when
 // Unicode is enabled and because the output of CommandLineToArgvW() is wchar_t.
 
+#include <fcntl.h>
+#include <io.h>
 #include <wchar.h>
 #include <windows.h>
 #include <shellapi.h>
@@ -55,8 +59,16 @@
 
 #define WFOPEN(ARG, OPT) _wfopen((const W_CHAR*)ARG, TO_W_CHAR(OPT))
 
-#define WPRINTF(STR, ...) wprintf(TO_W_CHAR(STR), __VA_ARGS__)
-#define WFPRINTF(STDERR, STR, ...) fwprintf(STDERR, TO_W_CHAR(STR), __VA_ARGS__)
+#define WFPRINTF(STREAM, STR, ...)                    \
+  do {                                                \
+    int prev_mode;                                    \
+    fflush(STREAM);                                   \
+    prev_mode = _setmode(_fileno(STREAM), _O_U8TEXT); \
+    fwprintf(STREAM, TO_W_CHAR(STR), __VA_ARGS__);    \
+    fflush(STREAM);                                   \
+    (void)_setmode(_fileno(STREAM), prev_mode);       \
+  } while (0)
+#define WPRINTF(STR, ...) WFPRINTF(stdout, STR, __VA_ARGS__)
 
 #define WSTRLEN(FILENAME) wcslen((const W_CHAR*)FILENAME)
 #define WSTRCMP(FILENAME, STR) wcscmp((const W_CHAR*)FILENAME, TO_W_CHAR(STR))
@@ -65,6 +77,8 @@
 
 #else
 
+#include <string.h>
+
 // Unicode file paths work as is on Unix platforms, and no extra work is done on
 // Windows either if Unicode is disabled.
 
@@ -83,7 +97,7 @@
 #define WFOPEN(ARG, OPT) fopen(ARG, OPT)
 
 #define WPRINTF(STR, ...) printf(STR, __VA_ARGS__)
-#define WFPRINTF(STDERR, STR, ...) fprintf(STDERR, STR, __VA_ARGS__)
+#define WFPRINTF(STREAM, STR, ...) fprintf(STREAM, STR, __VA_ARGS__)
 
 #define WSTRLEN(FILENAME) strlen(FILENAME)
 #define WSTRCMP(FILENAME, STR) strcmp(FILENAME, STR)

examples/unicode_gif.h

@@ -45,18 +45,19 @@ static GifFileType* DGifOpenFileUnicode(const W_CHAR* file_name, int* error) {
   }
 
 #if defined(_WIN32) && defined(_UNICODE)
-
-  int file_handle = _wopen(file_name, _O_RDONLY | _O_BINARY);
-  if (file_handle == -1) {
-    if (error != NULL) *error = D_GIF_ERR_OPEN_FAILED;
-    return NULL;
-  }
+  {
+    int file_handle = _wopen(file_name, _O_RDONLY | _O_BINARY);
+    if (file_handle == -1) {
+      if (error != NULL) *error = D_GIF_ERR_OPEN_FAILED;
+      return NULL;
+    }
 
 #if LOCAL_GIF_PREREQ(5, 0)
-  return DGifOpenFileHandle(file_handle, error);
+    return DGifOpenFileHandle(file_handle, error);
 #else
-  return DGifOpenFileHandle(file_handle);
+    return DGifOpenFileHandle(file_handle);
 #endif
+  }
 
 #else
 

examples/vwebp.c

@@ -18,6 +18,7 @@
 #define _POSIX_C_SOURCE 200112L  // for setenv
 #endif
 
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -292,6 +293,19 @@ static void PrintString(const char* const text) {
   }
 }
 
+static void PrintStringW(const char* const text) {
+#if defined(_WIN32) && defined(_UNICODE)
+  void* const font = GLUT_BITMAP_9_BY_15;
+  const W_CHAR* const wtext = (const W_CHAR*)text;
+  int i;
+  for (i = 0; wtext[i]; ++i) {
+    glutBitmapCharacter(font, wtext[i]);
+  }
+#else
+  PrintString(text);
+#endif
+}
+
 static float GetColorf(uint32_t color, int shift) {
   return ((color >> shift) & 0xff) / 255.f;
 }
@@ -396,7 +410,7 @@ static void HandleDisplay(void) {
 
     glColor4f(0.90f, 0.0f, 0.90f, 1.0f);
     glRasterPos2f(-0.95f, 0.90f);
-    PrintString(kParams.file_name);
+    PrintStringW(kParams.file_name);
 
     snprintf(tmp, sizeof(tmp), "Dimension:%d x %d", pic->width, pic->height);
     glColor4f(0.90f, 0.0f, 0.90f, 1.0f);
@@ -417,10 +431,13 @@ static void HandleDisplay(void) {
 #endif
 }
 
-static void StartDisplay(void) {
+static void StartDisplay(const char* filename) {
   int width = kParams.canvas_width;
   int height = kParams.canvas_height;
   int screen_width, screen_height;
+  const char viewername[] = " - WebP viewer";
+  // max linux file len + viewername string
+  char title[4096 + sizeof(viewername)] = "";
   // TODO(webp:365) GLUT_DOUBLE results in flickering / old frames to be
   // partially displayed with animated webp + alpha.
 #if defined(__APPLE__) || defined(_WIN32)
@@ -440,8 +457,9 @@ static void StartDisplay(void) {
       height = screen_height;
     }
   }
+  snprintf(title, sizeof(title), "%s%s", filename, viewername);
   glutInitWindowSize(width, height);
-  glutCreateWindow("WebP viewer");
+  glutCreateWindow(title);
   glutDisplayFunc(HandleDisplay);
   glutReshapeFunc(HandleReshape);
   glutIdleFunc(NULL);
@@ -480,7 +498,7 @@ static void Help(void) {
 }
 
 int main(int argc, char* argv[]) {
-  int c;
+  int c, file_name_argv_index = 1;
   WebPDecoderConfig* const config = &kParams.config;
   WebPIterator* const curr = &kParams.curr_frame;
 
@@ -488,7 +506,7 @@ int main(int argc, char* argv[]) {
 
   if (!WebPInitDecoderConfig(config)) {
     fprintf(stderr, "Library version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
   config->options.dithering_strength = 50;
   config->options.alpha_dithering_strength = 100;
@@ -500,7 +518,7 @@ int main(int argc, char* argv[]) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-noicc")) {
       kParams.use_color_profile = 0;
     } else if (!strcmp(argv[c], "-nofancy")) {
@@ -523,30 +541,34 @@ int main(int argc, char* argv[]) {
              (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
              dec_version & 0xff, (dmux_version >> 16) & 0xff,
              (dmux_version >> 8) & 0xff, dmux_version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-mt")) {
       config->options.use_threads = 1;
     } else if (!strcmp(argv[c], "--")) {
-      if (c < argc - 1) kParams.file_name = (const char*)GET_WARGV(argv, ++c);
+      if (c < argc - 1) {
+        kParams.file_name = (const char*)GET_WARGV(argv, ++c);
+        file_name_argv_index = c;
+      }
       break;
     } else if (argv[c][0] == '-') {
       printf("Unknown option '%s'\n", argv[c]);
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       kParams.file_name = (const char*)GET_WARGV(argv, c);
+      file_name_argv_index = c;
     }
 
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
 
   if (kParams.file_name == NULL) {
     printf("missing input file!!\n");
     Help();
-    FREE_WARGV_AND_RETURN(0);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   if (!ImgIoUtilReadFile(kParams.file_name,
@@ -600,7 +622,7 @@ int main(int argc, char* argv[]) {
 
   // Position iterator to last frame. Next call to HandleDisplay will wrap over.
   // We take this into account by bumping up loop_count.
-  WebPDemuxGetFrame(kParams.dmux, 0, curr);
+  if (!WebPDemuxGetFrame(kParams.dmux, 0, curr)) goto Error;
   if (kParams.loop_count) ++kParams.loop_count;
 
 #if defined(__unix__) || defined(__CYGWIN__)
@@ -614,18 +636,18 @@ int main(int argc, char* argv[]) {
 #ifdef FREEGLUT
   glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, GLUT_ACTION_CONTINUE_EXECUTION);
 #endif
-  StartDisplay();
+  StartDisplay(argv[file_name_argv_index]);
 
   if (kParams.has_animation) glutTimerFunc(0, decode_callback, 0);
   glutMainLoop();
 
   // Should only be reached when using FREEGLUT:
   ClearParams();
-  FREE_WARGV_AND_RETURN(0);
+  FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
 
  Error:
   ClearParams();
-  FREE_WARGV_AND_RETURN(-1);
+  FREE_WARGV_AND_RETURN(EXIT_FAILURE);
 }
 
 #else   // !WEBP_HAVE_GL
@@ -633,7 +655,7 @@ int main(int argc, char* argv[]) {
 int main(int argc, const char* argv[]) {
   fprintf(stderr, "OpenGL support not enabled in %s.\n", argv[0]);
   (void)argc;
-  return 0;
+  return EXIT_FAILURE;
 }
 
 #endif

examples/webpinfo.c

@@ -14,6 +14,7 @@
 
 #include <assert.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifdef HAVE_CONFIG_H
 #include "webp/config.h"
@@ -357,12 +358,12 @@ static WebPInfoStatus ParseLossyHeader(const ChunkData* const chunk_data,
   }
   data += 3;
   data_size -= 3;
-  printf("  Key frame:        %s\n"
-         "  Profile:          %d\n"
-         "  Display:          %s\n"
-         "  Part. 0 length:   %d\n",
-         key_frame ? "Yes" : "No", profile,
-         display ? "Yes" : "No", partition0_length);
+  printf(
+      "  Key frame:        %s\n"
+      "  Profile:          %d\n"
+      "  Display:          Yes\n"
+      "  Part. 0 length:   %d\n",
+      key_frame ? "Yes" : "No", profile, partition0_length);
   if (key_frame) {
     if (!(data[0] == 0x9d && data[1] == 0x01 && data[2] == 0x2a)) {
       LOG_ERROR("Invalid lossy bitstream signature.");
@@ -1120,6 +1121,7 @@ static void Help(void) {
          "  -bitstream_info .... Parse bitstream header.\n");
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int c, quiet = 0, show_diag = 0, show_summary = 0;
   int parse_bitstream = 0;
@@ -1130,7 +1132,7 @@ int main(int argc, const char* argv[]) {
 
   if (argc == 1) {
     Help();
-    FREE_WARGV_AND_RETURN(WEBP_INFO_OK);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   // Parse command-line input.
@@ -1138,7 +1140,7 @@ int main(int argc, const char* argv[]) {
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help") ||
         !strcmp(argv[c], "-H") || !strcmp(argv[c], "-longhelp")) {
       Help();
-      FREE_WARGV_AND_RETURN(WEBP_INFO_OK);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-quiet")) {
       quiet = 1;
     } else if (!strcmp(argv[c], "-diag")) {
@@ -1151,7 +1153,7 @@ int main(int argc, const char* argv[]) {
       const int version = WebPGetDecoderVersion();
       printf("WebP Decoder version: %d.%d.%d\n",
              (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {  // Assume the remaining are all input files.
       break;
     }
@@ -1159,7 +1161,7 @@ int main(int argc, const char* argv[]) {
 
   if (c == argc) {
     Help();
-    FREE_WARGV_AND_RETURN(WEBP_INFO_INVALID_COMMAND);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   // Process input files one by one.
@@ -1182,5 +1184,6 @@ int main(int argc, const char* argv[]) {
     webp_info_status = AnalyzeWebP(&webp_info, &webp_data);
     WebPDataClear(&webp_data);
   }
-  FREE_WARGV_AND_RETURN(webp_info_status);
+  FREE_WARGV_AND_RETURN((webp_info_status == WEBP_INFO_OK) ? EXIT_SUCCESS
+                                                           : EXIT_FAILURE);
 }

examples/webpmux.c

@@ -59,6 +59,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
 #include "webp/decode.h"
 #include "webp/mux.h"
 #include "../examples/example_util.h"
@@ -150,16 +151,20 @@ static const char* ErrorString(WebPMuxError err) {
 }
 
 #define RETURN_IF_ERROR(ERR_MSG)                                     \
-  if (err != WEBP_MUX_OK) {                                          \
-    fprintf(stderr, ERR_MSG);                                        \
-    return err;                                                      \
-  }
+  do {                                                               \
+    if (err != WEBP_MUX_OK) {                                        \
+      fprintf(stderr, ERR_MSG);                                      \
+      return err;                                                    \
+    }                                                                \
+  } while (0)
 
 #define RETURN_IF_ERROR3(ERR_MSG, FORMAT_STR1, FORMAT_STR2)          \
-  if (err != WEBP_MUX_OK) {                                          \
-    fprintf(stderr, ERR_MSG, FORMAT_STR1, FORMAT_STR2);              \
-    return err;                                                      \
-  }
+  do {                                                               \
+    if (err != WEBP_MUX_OK) {                                        \
+      fprintf(stderr, ERR_MSG, FORMAT_STR1, FORMAT_STR2);            \
+      return err;                                                    \
+    }                                                                \
+  } while (0)
 
 #define ERROR_GOTO1(ERR_MSG, LABEL)                                  \
   do {                                                               \
@@ -329,7 +334,7 @@ static void PrintHelp(void) {
   printf("\n");
   printf("DURATION_OPTIONS:\n");
   printf(" Set duration of selected frames:\n");
-  printf("   duration            set duration for each frames\n");
+  printf("   duration            set duration for all frames\n");
   printf("   duration,frame      set duration of a particular frame\n");
   printf("   duration,start,end  set duration of frames in the\n");
   printf("                        interval [start,end])\n");
@@ -348,7 +353,7 @@ static void PrintHelp(void) {
   printf("\n");
   printf("FRAME_OPTIONS(i):\n");
   printf(" Create animation:\n");
-  printf("   file_i +di+[xi+yi[+mi[bi]]]\n");
+  printf("   file_i +di[+xi+yi[+mi[bi]]]\n");
   printf("   where:    'file_i' is the i'th animation frame (WebP format),\n");
   printf("             'di' is the pause duration before next frame,\n");
   printf("             'xi','yi' specify the image offset for this frame,\n");
@@ -460,7 +465,8 @@ static WebPMux* DuplicateMuxHeader(const WebPMux* const mux) {
     if (err == WEBP_MUX_OK && metadata.size > 0) {
       err = WebPMuxSetChunk(new_mux, kFourccList[i], &metadata, 1);
       if (err != WEBP_MUX_OK) {
-        ERROR_GOTO1("Error transferring metadata in DuplicateMux().", End);
+        ERROR_GOTO1("Error transferring metadata in DuplicateMuxHeader().",
+                    End);
       }
     }
   }
@@ -604,20 +610,26 @@ static int ValidateCommandLine(const CommandLineArguments* const cmd_args,
 #define FEATURETYPE_IS_NIL (config->type_ == NIL_FEATURE)
 
 #define CHECK_NUM_ARGS_AT_LEAST(NUM, LABEL)                              \
-  if (argc < i + (NUM)) {                                                \
-    fprintf(stderr, "ERROR: Too few arguments for '%s'.\n", argv[i]);    \
-    goto LABEL;                                                          \
-  }
+  do {                                                                   \
+    if (argc < i + (NUM)) {                                              \
+      fprintf(stderr, "ERROR: Too few arguments for '%s'.\n", argv[i]);  \
+      goto LABEL;                                                        \
+    }                                                                    \
+  } while (0)
 
 #define CHECK_NUM_ARGS_AT_MOST(NUM, LABEL)                               \
-  if (argc > i + (NUM)) {                                                \
-    fprintf(stderr, "ERROR: Too many arguments for '%s'.\n", argv[i]);   \
-    goto LABEL;                                                          \
-  }
+  do {                                                                   \
+    if (argc > i + (NUM)) {                                              \
+      fprintf(stderr, "ERROR: Too many arguments for '%s'.\n", argv[i]); \
+      goto LABEL;                                                        \
+    }                                                                    \
+  } while (0)
 
 #define CHECK_NUM_ARGS_EXACTLY(NUM, LABEL)                               \
-  CHECK_NUM_ARGS_AT_LEAST(NUM, LABEL);                                   \
-  CHECK_NUM_ARGS_AT_MOST(NUM, LABEL);
+  do {                                                                   \
+    CHECK_NUM_ARGS_AT_LEAST(NUM, LABEL);                                 \
+    CHECK_NUM_ARGS_AT_MOST(NUM, LABEL);                                  \
+  } while (0)
 
 // Parses command-line arguments to fill up config object. Also performs some
 // semantic checks. unicode_argv contains wchar_t arguments or is null.
@@ -684,7 +696,7 @@ static int ParseCommandLine(Config* config, const W_CHAR** const unicode_argv) {
           ERROR_GOTO1("ERROR: Multiple features specified.\n", ErrParse);
         }
         arg->subtype_ = SUBTYPE_ANMF;
-        arg->filename_ = argv[i + 1];
+        arg->filename_ = wargv[i + 1];
         arg->params_ = argv[i + 2];
         ++feature_arg_index;
         i += 3;
@@ -1214,6 +1226,7 @@ static int Process(const Config* config) {
 //------------------------------------------------------------------------------
 // Main.
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   Config config;
   int ok;
@@ -1227,7 +1240,7 @@ int main(int argc, const char* argv[]) {
     PrintHelp();
   }
   DeleteConfig(&config);
-  FREE_WARGV_AND_RETURN(!ok);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 //------------------------------------------------------------------------------

extras/Makefile.am

@@ -7,6 +7,7 @@ noinst_HEADERS += ../src/webp/types.h
 
 libwebpextras_la_SOURCES =
 libwebpextras_la_SOURCES += extras.c extras.h quality_estimate.c
+libwebpextras_la_SOURCES += sharpyuv_risk_table.c sharpyuv_risk_table.h
 
 libwebpextras_la_CPPFLAGS = $(AM_CPPFLAGS)
 libwebpextras_la_LDFLAGS = -lm

extras/extras.c

@@ -11,15 +11,21 @@
 //
 
 #include "extras/extras.h"
-#include "webp/format_constants.h"
-#include "src/dsp/dsp.h"
 
 #include <assert.h>
+#include <limits.h>
 #include <string.h>
 
+#include "extras/sharpyuv_risk_table.h"
+#include "sharpyuv/sharpyuv.h"
+#include "src/dsp/dsp.h"
+#include "src/utils/utils.h"
+#include "webp/format_constants.h"
+#include "webp/types.h"
+
 #define XTRA_MAJ_VERSION 1
-#define XTRA_MIN_VERSION 2
-#define XTRA_REV_VERSION 2
+#define XTRA_MIN_VERSION 4
+#define XTRA_REV_VERSION 0
 
 //------------------------------------------------------------------------------
 
@@ -160,3 +166,159 @@ int WebPUnmultiplyARGB(WebPPicture* pic) {
 }
 
 //------------------------------------------------------------------------------
+// 420 risk metric
+
+#define YUV_FIX 16  // fixed-point precision for RGB->YUV
+static const int kYuvHalf = 1 << (YUV_FIX - 1);
+
+// Maps a value in [0, (256 << YUV_FIX) - 1] to [0,
+// precomputed_scores_table_sampling - 1]. It is important that the extremal
+// values are preserved and 1:1 mapped:
+//  ConvertValue(0) = 0
+//  ConvertValue((256 << 16) - 1) = rgb_sampling_size - 1
+static int SharpYuvConvertValueToSampledIdx(int v, int rgb_sampling_size) {
+  v = (v + kYuvHalf) >> YUV_FIX;
+  v = (v < 0) ? 0 : (v > 255) ? 255 : v;
+  return (v * (rgb_sampling_size - 1)) / 255;
+}
+
+#undef YUV_FIX
+
+// For each pixel, computes the index to look up that color in a precomputed
+// risk score table where the YUV space is subsampled to a size of
+// precomputed_scores_table_sampling^3 (see sharpyuv_risk_table.h)
+static int SharpYuvConvertToYuvSharpnessIndex(
+    int r, int g, int b, const SharpYuvConversionMatrix* matrix,
+    int precomputed_scores_table_sampling) {
+  const int y = SharpYuvConvertValueToSampledIdx(
+      matrix->rgb_to_y[0] * r + matrix->rgb_to_y[1] * g +
+          matrix->rgb_to_y[2] * b + matrix->rgb_to_y[3],
+      precomputed_scores_table_sampling);
+  const int u = SharpYuvConvertValueToSampledIdx(
+      matrix->rgb_to_u[0] * r + matrix->rgb_to_u[1] * g +
+          matrix->rgb_to_u[2] * b + matrix->rgb_to_u[3],
+      precomputed_scores_table_sampling);
+  const int v = SharpYuvConvertValueToSampledIdx(
+      matrix->rgb_to_v[0] * r + matrix->rgb_to_v[1] * g +
+          matrix->rgb_to_v[2] * b + matrix->rgb_to_v[3],
+      precomputed_scores_table_sampling);
+  return y + u * precomputed_scores_table_sampling +
+         v * precomputed_scores_table_sampling *
+             precomputed_scores_table_sampling;
+}
+
+static void SharpYuvRowToYuvSharpnessIndex(
+    const uint8_t* r_ptr, const uint8_t* g_ptr, const uint8_t* b_ptr,
+    int rgb_step, int rgb_bit_depth, int width, uint16_t* dst,
+    const SharpYuvConversionMatrix* matrix,
+    int precomputed_scores_table_sampling) {
+  int i;
+  assert(rgb_bit_depth == 8);
+  (void)rgb_bit_depth;  // Unused for now.
+  for (i = 0; i < width;
+       ++i, r_ptr += rgb_step, g_ptr += rgb_step, b_ptr += rgb_step) {
+    dst[i] =
+        SharpYuvConvertToYuvSharpnessIndex(r_ptr[0], g_ptr[0], b_ptr[0], matrix,
+                                           precomputed_scores_table_sampling);
+  }
+}
+
+#define SAFE_ALLOC(W, H, T) ((T*)WebPSafeMalloc((uint64_t)(W) * (H), sizeof(T)))
+
+static int DoEstimateRisk(const uint8_t* r_ptr, const uint8_t* g_ptr,
+                          const uint8_t* b_ptr, int rgb_step, int rgb_stride,
+                          int rgb_bit_depth, int width, int height,
+                          const SharpYuvOptions* options,
+                          const uint8_t precomputed_scores_table[],
+                          int precomputed_scores_table_sampling,
+                          float* score_out) {
+  const int sampling3 = precomputed_scores_table_sampling *
+                        precomputed_scores_table_sampling *
+                        precomputed_scores_table_sampling;
+  const int kNoiseLevel = 4;
+  double total_score = 0;
+  double count = 0;
+  // Rows of indices in
+  uint16_t* row1 = SAFE_ALLOC(width, 1, uint16_t);
+  uint16_t* row2 = SAFE_ALLOC(width, 1, uint16_t);
+  uint16_t* tmp;
+  int i, j;
+
+  if (row1 == NULL || row2 == NULL) {
+    WebPFree(row1);
+    WebPFree(row2);
+    return 0;
+  }
+
+  // Convert the first row ahead.
+  SharpYuvRowToYuvSharpnessIndex(r_ptr, g_ptr, b_ptr, rgb_step, rgb_bit_depth,
+                                 width, row2, options->yuv_matrix,
+                                 precomputed_scores_table_sampling);
+
+  for (j = 1; j < height; ++j) {
+    r_ptr += rgb_stride;
+    g_ptr += rgb_stride;
+    b_ptr += rgb_stride;
+    // Swap row 1 and row 2.
+    tmp = row1;
+    row1 = row2;
+    row2 = tmp;
+    // Convert the row below.
+    SharpYuvRowToYuvSharpnessIndex(r_ptr, g_ptr, b_ptr, rgb_step, rgb_bit_depth,
+                                   width, row2, options->yuv_matrix,
+                                   precomputed_scores_table_sampling);
+    for (i = 0; i < width - 1; ++i) {
+      const int idx0 = row1[i + 0];
+      const int idx1 = row1[i + 1];
+      const int idx2 = row2[i + 0];
+      const int score = precomputed_scores_table[idx0 + sampling3 * idx1] +
+                        precomputed_scores_table[idx0 + sampling3 * idx2] +
+                        precomputed_scores_table[idx1 + sampling3 * idx2];
+      if (score > kNoiseLevel) {
+        total_score += score;
+        count += 1.0;
+      }
+    }
+  }
+  if (count > 0.) total_score /= count;
+
+  // If less than 1% of pixels were evaluated -> below noise level.
+  if (100. * count / (width * height) < 1.) total_score = 0.;
+
+  // Rescale to [0:100]
+  total_score = (total_score > 25.) ? 100. : total_score * 100. / 25.;
+
+  WebPFree(row1);
+  WebPFree(row2);
+
+  *score_out = (float)total_score;
+  return 1;
+}
+
+#undef SAFE_ALLOC
+
+int SharpYuvEstimate420Risk(const void* r_ptr, const void* g_ptr,
+                            const void* b_ptr, int rgb_step, int rgb_stride,
+                            int rgb_bit_depth, int width, int height,
+                            const SharpYuvOptions* options, float* score) {
+  if (width < 1 || height < 1 || width == INT_MAX || height == INT_MAX ||
+      r_ptr == NULL || g_ptr == NULL || b_ptr == NULL || options == NULL ||
+      score == NULL) {
+    return 0;
+  }
+  if (rgb_bit_depth != 8) {
+    return 0;
+  }
+
+  if (width <= 4 || height <= 4) {
+    *score = 0.0f;  // too small, no real risk.
+    return 1;
+  }
+
+  return DoEstimateRisk(
+      (const uint8_t*)r_ptr, (const uint8_t*)g_ptr, (const uint8_t*)b_ptr,
+      rgb_step, rgb_stride, rgb_bit_depth, width, height, options,
+      kSharpYuvPrecomputedRisk, kSharpYuvPrecomputedRiskYuvSampling, score);
+}
+
+//------------------------------------------------------------------------------

extras/extras.h

@@ -17,9 +17,10 @@
 extern "C" {
 #endif
 
+#include "sharpyuv/sharpyuv.h"
 #include "webp/encode.h"
 
-#define WEBP_EXTRAS_ABI_VERSION 0x0002    // MAJOR(8b) + MINOR(8b)
+#define WEBP_EXTRAS_ABI_VERSION 0x0003    // MAJOR(8b) + MINOR(8b)
 
 //------------------------------------------------------------------------------
 
@@ -70,6 +71,38 @@ WEBP_EXTERN int VP8EstimateQuality(const uint8_t* const data, size_t size);
 
 //------------------------------------------------------------------------------
 
+// Computes a score between 0 and 100 which represents the risk of having visual
+// quality loss from converting an RGB image to YUV420.
+// A low score, typically < 40, means there is a low risk of artifacts from
+// chroma subsampling and a simple averaging algorithm can be used instead of
+// the more expensive SharpYuvConvert function.
+// A medium score, typically >= 40 and < 70, means that simple chroma
+// subsampling will produce artifacts and it may be advisable to use the more
+// costly SharpYuvConvert for YUV420 conversion.
+// A high score, typically >= 70, means there is a very high risk of artifacts
+// from chroma subsampling even with SharpYuvConvert, and best results might be
+// achieved by using YUV444.
+// If not using SharpYuvConvert, a threshold of about 50 can be used to decide
+// between (simple averaging) 420 and 444.
+// r_ptr, g_ptr, b_ptr: pointers to the source r, g and b channels. Should point
+//     to uint8_t buffers if rgb_bit_depth is 8, or uint16_t buffers otherwise.
+// rgb_step: distance in bytes between two horizontally adjacent pixels on the
+//     r, g and b channels. If rgb_bit_depth is > 8, it should be a
+//     multiple of 2.
+// rgb_stride: distance in bytes between two vertically adjacent pixels on the
+//     r, g, and b channels. If rgb_bit_depth is > 8, it should be a
+//     multiple of 2.
+// rgb_bit_depth: number of bits for each r/g/b value. Only a value of 8 is
+//     currently supported.
+// width, height: width and height of the image in pixels
+// Returns 0 on failure.
+WEBP_EXTERN int SharpYuvEstimate420Risk(
+    const void* r_ptr, const void* g_ptr, const void* b_ptr, int rgb_step,
+    int rgb_stride, int rgb_bit_depth, int width, int height,
+    const SharpYuvOptions* options, float* score);
+
+//------------------------------------------------------------------------------
+
 #ifdef __cplusplus
 }    // extern "C"
 #endif

extras/get_disto.c

@@ -223,13 +223,15 @@ static void Help(void) {
           "  -o <file> . save the diff map as a WebP lossless file\n"
           "  -scale .... scale the difference map to fit [0..255] range\n"
           "  -gray ..... use grayscale for difference map (-scale)\n"
-          " Also handles PNG, JPG and TIFF files, in addition to WebP.\n");
+          "\nSupported input formats:\n  %s\n",
+          WebPGetEnabledInputFileFormats());
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   WebPPicture pic1, pic2;
   size_t size1 = 0, size2 = 0;
-  int ret = 1;
+  int ret = EXIT_FAILURE;
   float disto[5];
   int type = 0;
   int c;
@@ -245,7 +247,7 @@ int main(int argc, const char* argv[]) {
 
   if (!WebPPictureInit(&pic1) || !WebPPictureInit(&pic2)) {
     fprintf(stderr, "Can't init pictures\n");
-    FREE_WARGV_AND_RETURN(1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   for (c = 1; c < argc; ++c) {
@@ -261,7 +263,7 @@ int main(int argc, const char* argv[]) {
       use_gray = 1;
     } else if (!strcmp(argv[c], "-h")) {
       help = 1;
-      ret = 0;
+      ret = EXIT_SUCCESS;
     } else if (!strcmp(argv[c], "-o")) {
       if (++c == argc) {
         fprintf(stderr, "missing file name after %s option.\n", argv[c - 1]);
@@ -336,7 +338,8 @@ int main(int argc, const char* argv[]) {
       fprintf(stderr, "Error during lossless encoding.\n");
       goto End;
     }
-    ret = ImgIoUtilWriteFile(output, data, data_size) ? 0 : 1;
+    ret = ImgIoUtilWriteFile(output, data, data_size) ? EXIT_SUCCESS
+                                                      : EXIT_FAILURE;
     WebPFree(data);
     if (ret) goto End;
 #else
@@ -344,9 +347,10 @@ int main(int argc, const char* argv[]) {
     (void)data_size;
     fprintf(stderr, "Cannot save the difference map. Please recompile "
                     "without the WEBP_REDUCE_CSP flag.\n");
+    goto End;
 #endif  // WEBP_REDUCE_CSP
   }
-  ret = 0;
+  ret = EXIT_SUCCESS;
 
  End:
   WebPPictureFree(&pic1);

extras/sharpyuv_risk_table.h

@@ -0,0 +1,27 @@
+// Copyright 2023 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Precomputed data for 420 risk estimation.
+
+#ifndef WEBP_EXTRAS_SHARPYUV_RISK_TABLE_H_
+#define WEBP_EXTRAS_SHARPYUV_RISK_TABLE_H_
+
+#include "src/webp/types.h"
+
+extern const int kSharpYuvPrecomputedRiskYuvSampling;
+// Table of precomputed risk scores when chroma subsampling images with two
+// given colors.
+// Since precomputing values for all possible YUV colors would create a huge
+// table, the YUV space (i.e. [0, 255]^3) is reduced to
+// [0, kSharpYuvPrecomputedRiskYuvSampling-1]^3
+// where 255 maps to kSharpYuvPrecomputedRiskYuvSampling-1.
+// Table size: kSharpYuvPrecomputedRiskYuvSampling^6 bytes or 114 KiB
+extern const uint8_t kSharpYuvPrecomputedRisk[];
+
+#endif  // WEBP_EXTRAS_SHARPYUV_RISK_TABLE_H_

extras/vwebp_sdl.c

@@ -15,6 +15,7 @@
 // Author: James Zern (jzern@google.com)
 
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifdef HAVE_CONFIG_H
 #include "webp/config.h"
@@ -30,7 +31,7 @@
 #if defined(WEBP_HAVE_JUST_SDL_H)
 #include <SDL.h>
 #else
-#include <SDL/SDL.h>
+#include <SDL2/SDL.h>
 #endif
 
 static void ProcessEvents(void) {
@@ -49,6 +50,7 @@ static void ProcessEvents(void) {
   }
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, char* argv[]) {
   int c;
   int ok = 0;
@@ -61,7 +63,7 @@ int main(int argc, char* argv[]) {
     size_t webp_size = 0;
     if (!strcmp(argv[c], "-h")) {
       printf("Usage: %s [-h] image.webp [more_files.webp...]\n", argv[0]);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {
       file = (const char*)GET_WARGV(argv, c);
     }
@@ -75,7 +77,7 @@ int main(int argc, char* argv[]) {
       fprintf(stderr, "File too large.\n");
       goto Error;
     }
-    ok = WebpToSDL((const char*)webp, (int)webp_size);
+    ok = WebPToSDL((const char*)webp, (int)webp_size);
     free((void*)webp);
     if (!ok) {
       WFPRINTF(stderr, "Error decoding file %s\n", (const W_CHAR*)file);
@@ -87,7 +89,7 @@ int main(int argc, char* argv[]) {
 
  Error:
   SDL_Quit();
-  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 #else  // !WEBP_HAVE_SDL

extras/webp_quality.c

@@ -15,6 +15,7 @@
 #include "imageio/imageio_util.h"
 #include "../examples/unicode.h"
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int c;
   int quiet = 0;
@@ -27,7 +28,7 @@ int main(int argc, const char* argv[]) {
       quiet = 1;
     } else if (!strcmp(argv[c], "-help") || !strcmp(argv[c], "-h")) {
       printf("webp_quality [-h][-quiet] webp_files...\n");
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {
       const char* const filename = (const char*)GET_WARGV(argv, c);
       const uint8_t* data = NULL;
@@ -50,5 +51,5 @@ int main(int argc, const char* argv[]) {
       free((void*)data);
     }
   }
-  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }

extras/webp_to_sdl.c

@@ -20,88 +20,75 @@
 #include "webp_to_sdl.h"
 
 #include <stdio.h>
+
 #include "src/webp/decode.h"
 
 #if defined(WEBP_HAVE_JUST_SDL_H)
 #include <SDL.h>
 #else
-#include <SDL/SDL.h>
+#include <SDL2/SDL.h>
 #endif
 
 static int init_ok = 0;
-int WebpToSDL(const char* data, unsigned int data_size) {
+int WebPToSDL(const char* data, unsigned int data_size) {
   int ok = 0;
   VP8StatusCode status;
-  WebPDecoderConfig config;
-  WebPBitstreamFeatures* const input = &config.input;
-  WebPDecBuffer* const output = &config.output;
-  SDL_Surface* screen = NULL;
-  SDL_Surface* surface = NULL;
-
-  if (!WebPInitDecoderConfig(&config)) {
-    fprintf(stderr, "Library version mismatch!\n");
-    return 0;
-  }
+  WebPBitstreamFeatures input;
+  uint8_t* output = NULL;
+  SDL_Window* window = NULL;
+  SDL_Renderer* renderer = NULL;
+  SDL_Texture* texture = NULL;
+  int width, height;
 
   if (!init_ok) {
     SDL_Init(SDL_INIT_VIDEO);
     init_ok = 1;
   }
 
-  status = WebPGetFeatures((uint8_t*)data, (size_t)data_size, &config.input);
+  status = WebPGetFeatures((uint8_t*)data, (size_t)data_size, &input);
   if (status != VP8_STATUS_OK) goto Error;
+  width = input.width;
+  height = input.height;
 
-  screen = SDL_SetVideoMode(input->width, input->height, 32, SDL_SWSURFACE);
-  if (screen == NULL) {
-    fprintf(stderr, "Unable to set video mode (32bpp %dx%d)!\n",
-            input->width, input->height);
+  SDL_CreateWindowAndRenderer(width, height, 0, &window, &renderer);
+  if (window == NULL || renderer == NULL) {
+    fprintf(stderr, "Unable to create window or renderer!\n");
     goto Error;
   }
+  SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY,
+              "linear");  // make the scaled rendering look smoother.
+  SDL_RenderSetLogicalSize(renderer, width, height);
 
-  surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
-                                 input->width, input->height, 32,
-                                 0x000000ffu,   // R mask
-                                 0x0000ff00u,   // G mask
-                                 0x00ff0000u,   // B mask
-                                 0xff000000u);  // A mask
-
-  if (surface == NULL) {
-    fprintf(stderr, "Unable to create %dx%d RGBA surface!\n",
-            input->width, input->height);
+  texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ABGR8888,
+                              SDL_TEXTUREACCESS_STREAMING, width, height);
+  if (texture == NULL) {
+    fprintf(stderr, "Unable to create %dx%d RGBA texture!\n", width, height);
     goto Error;
   }
-  if (SDL_MUSTLOCK(surface)) SDL_LockSurface(surface);
 
 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
-  output->colorspace = MODE_BGRA;
+  output = WebPDecodeBGRA((const uint8_t*)data, (size_t)data_size, &width,
+                          &height);
 #else
-  output->colorspace = MODE_RGBA;
+  output = WebPDecodeRGBA((const uint8_t*)data, (size_t)data_size, &width,
+                          &height);
 #endif
-  output->width  = surface->w;
-  output->height = surface->h;
-  output->u.RGBA.rgba   = surface->pixels;
-  output->u.RGBA.stride = surface->pitch;
-  output->u.RGBA.size   = surface->pitch * surface->h;
-  output->is_external_memory = 1;
-
-  status = WebPDecode((const uint8_t*)data, (size_t)data_size, &config);
-  if (status != VP8_STATUS_OK) {
+  if (output == NULL) {
     fprintf(stderr, "Error decoding image (%d)\n", status);
     goto Error;
   }
 
-  if (SDL_MUSTLOCK(surface)) SDL_UnlockSurface(surface);
-  if (SDL_BlitSurface(surface, NULL, screen, NULL) ||
-      SDL_Flip(screen)) {
-    goto Error;
-  }
-
+  SDL_UpdateTexture(texture, NULL, output, width * sizeof(uint32_t));
+  SDL_RenderClear(renderer);
+  SDL_RenderCopy(renderer, texture, NULL, NULL);
+  SDL_RenderPresent(renderer);
   ok = 1;
 
  Error:
-  SDL_FreeSurface(surface);
-  SDL_FreeSurface(screen);
-  WebPFreeDecBuffer(output);
+  // We should call SDL_DestroyWindow(window) but that makes .js fail.
+  SDL_DestroyRenderer(renderer);
+  SDL_DestroyTexture(texture);
+  WebPFree(output);
   return ok;
 }
 

extras/webp_to_sdl.h

@@ -14,9 +14,9 @@
 #ifndef WEBP_EXTRAS_WEBP_TO_SDL_H_
 #define WEBP_EXTRAS_WEBP_TO_SDL_H_
 
-// Exports the method WebpToSDL(const char* data, int data_size) which decodes
+// Exports the method WebPToSDL(const char* data, int data_size) which decodes
 // a WebP bitstream into an RGBA SDL surface.
 // Return false on failure.
-extern int WebpToSDL(const char* data, unsigned int data_size);
+extern int WebPToSDL(const char* data, unsigned int data_size);
 
 #endif  // WEBP_EXTRAS_WEBP_TO_SDL_H_

imageio/Android.mk

@@ -1,3 +1,5 @@
+# Ignore this file during non-NDK builds.
+ifdef NDK_ROOT
 LOCAL_PATH := $(call my-dir)
 
 ################################################################################
@@ -52,3 +54,4 @@ LOCAL_STATIC_LIBRARIES := imageio_util
 LOCAL_MODULE := imageenc
 
 include $(BUILD_STATIC_LIBRARY)
+endif  # NDK_ROOT

imageio/image_dec.c

@@ -11,6 +11,24 @@
 
 #include "./image_dec.h"
 
+const char* WebPGetEnabledInputFileFormats(void) {
+  return "WebP"
+#ifdef WEBP_HAVE_JPEG
+         ", JPEG"
+#endif
+#ifdef WEBP_HAVE_PNG
+         ", PNG"
+#endif
+         ", PNM (PGM, PPM, PAM)"
+#ifdef WEBP_HAVE_TIFF
+         ", TIFF"
+#endif
+#ifdef HAVE_WINCODEC_H
+         ", Windows Imaging Component (WIC)"
+#endif
+         "";
+}
+
 static WEBP_INLINE uint32_t GetBE32(const uint8_t buf[]) {
   return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
 }

imageio/image_dec.h

@@ -41,6 +41,9 @@ typedef enum {
   WEBP_UNSUPPORTED_FORMAT
 } WebPInputFileFormat;
 
+// Returns a comma separated list of enabled input formats.
+const char* WebPGetEnabledInputFileFormats(void);
+
 // Try to infer the image format. 'data_size' should be larger than 12.
 // Returns WEBP_UNSUPPORTED_FORMAT if format can't be guess safely.
 WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,

imageio/image_enc.c

@@ -260,14 +260,20 @@ int WebPWritePAM(FILE* fout, const WebPDecBuffer* const buffer) {
 
 // Save 16b mode (RGBA4444, RGB565, ...) for debugging purpose.
 int WebPWrite16bAsPGM(FILE* fout, const WebPDecBuffer* const buffer) {
-  const uint32_t width = buffer->width;
-  const uint32_t height = buffer->height;
-  const uint8_t* rgba = buffer->u.RGBA.rgba;
-  const int stride = buffer->u.RGBA.stride;
+  uint32_t width, height;
+  uint8_t* rgba;
+  int stride;
   const uint32_t bytes_per_px = 2;
   uint32_t y;
 
-  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+  if (fout == NULL || buffer == NULL) return 0;
+
+  width = buffer->width;
+  height = buffer->height;
+  rgba = buffer->u.RGBA.rgba;
+  stride = buffer->u.RGBA.stride;
+
+  if (rgba == NULL) return 0;
 
   fprintf(fout, "P5\n%u %u\n255\n", width * bytes_per_px, height);
   for (y = 0; y < height; ++y) {
@@ -295,22 +301,29 @@ static void PutLE32(uint8_t* const dst, uint32_t value) {
 #define BMP_HEADER_SIZE 54
 #define BMP_HEADER_ALPHA_EXTRA_SIZE 16  // for alpha info
 int WebPWriteBMP(FILE* fout, const WebPDecBuffer* const buffer) {
-  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
-  const int header_size =
-      BMP_HEADER_SIZE + (has_alpha ? BMP_HEADER_ALPHA_EXTRA_SIZE : 0);
-  const uint32_t width = buffer->width;
-  const uint32_t height = buffer->height;
-  const uint8_t* rgba = buffer->u.RGBA.rgba;
-  const int stride = buffer->u.RGBA.stride;
-  const uint32_t bytes_per_px = has_alpha ? 4 : 3;
+  int has_alpha, header_size;
+  uint32_t width, height;
+  uint8_t* rgba;
+  int stride;
   uint32_t y;
-  const uint32_t line_size = bytes_per_px * width;
-  const uint32_t bmp_stride = (line_size + 3) & ~3;   // pad to 4
-  const uint32_t image_size = bmp_stride * height;
-  const uint32_t total_size =  image_size + header_size;
+  uint32_t bytes_per_px, line_size, image_size, bmp_stride, total_size;
   uint8_t bmp_header[BMP_HEADER_SIZE + BMP_HEADER_ALPHA_EXTRA_SIZE] = { 0 };
 
-  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+  if (fout == NULL || buffer == NULL) return 0;
+
+  has_alpha = WebPIsAlphaMode(buffer->colorspace);
+  header_size = BMP_HEADER_SIZE + (has_alpha ? BMP_HEADER_ALPHA_EXTRA_SIZE : 0);
+  width = buffer->width;
+  height = buffer->height;
+  rgba = buffer->u.RGBA.rgba;
+  stride = buffer->u.RGBA.stride;
+  bytes_per_px = has_alpha ? 4 : 3;
+  line_size = bytes_per_px * width;
+  bmp_stride = (line_size + 3) & ~3;  // pad to 4
+  image_size = bmp_stride * height;
+  total_size = image_size + header_size;
+
+  if (rgba == NULL) return 0;
 
   // bitmap file header
   PutLE16(bmp_header + 0, 0x4d42);                // signature 'BM'
@@ -372,17 +385,14 @@ int WebPWriteBMP(FILE* fout, const WebPDecBuffer* const buffer) {
 #define TIFF_HEADER_SIZE (EXTRA_DATA_OFFSET + EXTRA_DATA_SIZE)
 
 int WebPWriteTIFF(FILE* fout, const WebPDecBuffer* const buffer) {
-  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
-  const uint32_t width = buffer->width;
-  const uint32_t height = buffer->height;
-  const uint8_t* rgba = buffer->u.RGBA.rgba;
-  const int stride = buffer->u.RGBA.stride;
-  const uint8_t bytes_per_px = has_alpha ? 4 : 3;
-  const uint8_t assoc_alpha =
-      WebPIsPremultipliedMode(buffer->colorspace) ? 1 : 2;
+  int has_alpha;
+  uint32_t width, height;
+  uint8_t* rgba;
+  int stride;
+  uint8_t bytes_per_px = 0;
+  const uint8_t assoc_alpha = 0;
   // For non-alpha case, we omit tag 0x152 (ExtraSamples).
-  const uint8_t num_ifd_entries = has_alpha ? NUM_IFD_ENTRIES
-                                            : NUM_IFD_ENTRIES - 1;
+  const uint8_t num_ifd_entries = 0;
   uint8_t tiff_header[TIFF_HEADER_SIZE] = {
     0x49, 0x49, 0x2a, 0x00,   // little endian signature
     8, 0, 0, 0,               // offset to the unique IFD that follows
@@ -416,7 +426,20 @@ int WebPWriteTIFF(FILE* fout, const WebPDecBuffer* const buffer) {
   };
   uint32_t y;
 
-  if (fout == NULL || buffer == NULL || rgba == NULL) return 0;
+  if (fout == NULL || buffer == NULL) return 0;
+
+  has_alpha = WebPIsAlphaMode(buffer->colorspace);
+  width = buffer->width;
+  height = buffer->height;
+  rgba = buffer->u.RGBA.rgba;
+  stride = buffer->u.RGBA.stride;
+
+  if (rgba == NULL) return 0;
+
+  // Update bytes_per_px, num_ifd_entries and assoc_alpha.
+  tiff_header[38] = tiff_header[102] = bytes_per_px = has_alpha ? 4 : 3;
+  tiff_header[8] = has_alpha ? NUM_IFD_ENTRIES : NUM_IFD_ENTRIES - 1;
+  tiff_header[186] = WebPIsPremultipliedMode(buffer->colorspace) ? 1 : 2;
 
   // Fill placeholders in IFD:
   PutLE32(tiff_header + 10 + 8, width);

imageio/imageio_util.c

@@ -89,6 +89,11 @@ int ImgIoUtilReadFile(const char* const file_name,
   }
   fseek(in, 0, SEEK_END);
   file_size = ftell(in);
+  if (file_size == (size_t)-1) {
+    fclose(in);
+    WFPRINTF(stderr, "error getting size of '%s'\n", (const W_CHAR*)file_name);
+    return 0;
+  }
   fseek(in, 0, SEEK_SET);
   // we allocate one extra byte for the \0 terminator
   file_data = (uint8_t*)WebPMalloc(file_size + 1);

imageio/jpegdec.c

@@ -206,8 +206,18 @@ struct my_error_mgr {
 
 static void my_error_exit(j_common_ptr dinfo) {
   struct my_error_mgr* myerr = (struct my_error_mgr*)dinfo->err;
+  // The following code is disabled in fuzzing mode because:
+  // - the logs can be flooded due to invalid JPEG files
+  // - msg_code is wrongfully seen as uninitialized by msan when the libjpeg
+  //   dependency is not built with sanitizers enabled
+#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+  const int msg_code = myerr->pub.msg_code;
   fprintf(stderr, "libjpeg error: ");
   dinfo->err->output_message(dinfo);
+  if (msg_code == JERR_INPUT_EOF || msg_code == JERR_FILE_READ) {
+    fprintf(stderr, "`jpegtran -copy all` MAY be able to process this file.\n");
+  }
+#endif
   longjmp(myerr->setjmp_buffer, 1);
 }
 

imageio/pngdec.c

@@ -235,7 +235,7 @@ int ReadPNG(const uint8_t* const data, size_t data_size,
   volatile png_infop end_info = NULL;
   PNGReadContext context = { NULL, 0, 0 };
   int color_type, bit_depth, interlaced;
-  int has_alpha;
+  int num_channels;
   int num_passes;
   int p;
   volatile int ok = 0;
@@ -293,9 +293,6 @@ int ReadPNG(const uint8_t* const data, size_t data_size,
   }
   if (png_get_valid(png, info, PNG_INFO_tRNS)) {
     png_set_tRNS_to_alpha(png);
-    has_alpha = 1;
-  } else {
-    has_alpha = !!(color_type & PNG_COLOR_MASK_ALPHA);
   }
 
   // Apply gamma correction if needed.
@@ -310,13 +307,16 @@ int ReadPNG(const uint8_t* const data, size_t data_size,
 
   if (!keep_alpha) {
     png_set_strip_alpha(png);
-    has_alpha = 0;
   }
 
   num_passes = png_set_interlace_handling(png);
   png_read_update_info(png, info);
 
-  stride = (int64_t)(has_alpha ? 4 : 3) * width * sizeof(*rgb);
+  num_channels = png_get_channels(png, info);
+  if (num_channels != 3 && num_channels != 4) {
+    goto Error;
+  }
+  stride = (int64_t)num_channels * width * sizeof(*rgb);
   if (stride != (int)stride ||
       !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
     goto Error;
@@ -341,8 +341,8 @@ int ReadPNG(const uint8_t* const data, size_t data_size,
 
   pic->width = (int)width;
   pic->height = (int)height;
-  ok = has_alpha ? WebPPictureImportRGBA(pic, rgb, (int)stride)
-                 : WebPPictureImportRGB(pic, rgb, (int)stride);
+  ok = (num_channels == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
+                           : WebPPictureImportRGB(pic, rgb, (int)stride);
 
   if (!ok) {
     goto Error;

imageio/pnmdec.c

@@ -20,6 +20,10 @@
 #include "webp/encode.h"
 #include "./imageio_util.h"
 
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf
+#endif
+
 typedef enum {
   WIDTH_FLAG      = 1 << 0,
   HEIGHT_FLAG     = 1 << 1,
@@ -111,8 +115,9 @@ static size_t ReadPAMFields(PNMInfo* const info, size_t off) {
       break;
     } else {
       static const char kEllipsis[] = " ...";
+      const size_t kLen = strlen(kEllipsis) + 1;  // +1 = trailing \0
       int i;
-      if (out_size > 20) sprintf(out + 20 - strlen(kEllipsis), kEllipsis);
+      if (out_size > 20) snprintf(out + 20 - kLen, kLen, kEllipsis);
       for (i = 0; i < (int)strlen(out); ++i) {
         // isprint() might trigger a "char-subscripts" warning if given a char.
         if (!isprint((int)out[i])) out[i] = ' ';

imageio/tiffdec.c

@@ -188,7 +188,9 @@ int ReadTIFF(const uint8_t* const data, size_t data_size,
     fprintf(stderr, "Error! Cannot retrieve TIFF samples-per-pixel info.\n");
     goto End;
   }
-  if (samples_per_px < 3 || samples_per_px > 4) goto End;  // not supported
+  if (!(samples_per_px == 1 || samples_per_px == 3 || samples_per_px == 4)) {
+    goto End;  // not supported
+  }
 
   if (!(TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &image_width) &&
         TIFFGetField(tif, TIFFTAG_IMAGELENGTH, &image_height))) {
@@ -212,7 +214,7 @@ int ReadTIFF(const uint8_t* const data, size_t data_size,
       TIFFGetField(tif, TIFFTAG_TILELENGTH, &tile_height)) {
     if ((tile_width > 32 && tile_width / 2 > image_width) ||
         (tile_height > 32 && tile_height / 2 > image_height) ||
-        ImgIoUtilCheckSizeArgumentsOverflow(
+        !ImgIoUtilCheckSizeArgumentsOverflow(
             (uint64_t)tile_width * sizeof(*raster), tile_height)) {
       fprintf(stderr, "Error! TIFF tile dimension (%d x %d) is too large.\n",
               tile_width, tile_height);

infra/run_static_analysis.sh

@@ -85,10 +85,10 @@ scan_build make -j4
 
 index="$(find "${OUTPUT_DIR}" -name index.html)"
 if [[ -f "${index}" ]]; then
-  mv "$(dirname "${index}")/"* .
+  mv "$(dirname "${index}")/"* "${OUTPUT_DIR}"
 else
   # make a empty report to wipe out any old bug reports.
-  cat << EOT > index.html
+  cat << EOT > "${OUTPUT_DIR}/index.html"
 <html>
 <body>
 No bugs reported.

iosbuild.sh

@@ -41,6 +41,7 @@ readonly TARGETDIR="${TOPDIR}/WebP.framework"
 readonly DECTARGETDIR="${TOPDIR}/WebPDecoder.framework"
 readonly MUXTARGETDIR="${TOPDIR}/WebPMux.framework"
 readonly DEMUXTARGETDIR="${TOPDIR}/WebPDemux.framework"
+readonly SHARPYUVTARGETDIR="${TOPDIR}/SharpYuv.framework"
 readonly DEVELOPER=$(xcode-select --print-path)
 readonly PLATFORMSROOT="${DEVELOPER}/Platforms"
 readonly LIPO=$(xcrun -sdk iphoneos${SDK} -find lipo)
@@ -63,7 +64,8 @@ echo "Xcode Version: ${XCODE}"
 echo "iOS SDK Version: ${SDK}"
 
 if [[ -e "${BUILDDIR}" || -e "${TARGETDIR}" || -e "${DECTARGETDIR}" \
-      || -e "${MUXTARGETDIR}" || -e "${DEMUXTARGETDIR}" ]]; then
+      || -e "${MUXTARGETDIR}" || -e "${DEMUXTARGETDIR}" \
+      || -e "${SHARPYUVTARGETDIR}" ]]; then
   cat << EOF
 WARNING: The following directories will be deleted:
 WARNING:   ${BUILDDIR}
@@ -71,14 +73,16 @@ WARNING:   ${TARGETDIR}
 WARNING:   ${DECTARGETDIR}
 WARNING:   ${MUXTARGETDIR}
 WARNING:   ${DEMUXTARGETDIR}
+WARNING:   ${SHARPYUVTARGETDIR}
 WARNING: The build will continue in 5 seconds...
 EOF
   sleep 5
 fi
 rm -rf ${BUILDDIR} ${TARGETDIR} ${DECTARGETDIR} \
-    ${MUXTARGETDIR} ${DEMUXTARGETDIR}
+    ${MUXTARGETDIR} ${DEMUXTARGETDIR} ${SHARPYUVTARGETDIR}
 mkdir -p ${BUILDDIR} ${TARGETDIR}/Headers/ ${DECTARGETDIR}/Headers/ \
-    ${MUXTARGETDIR}/Headers/ ${DEMUXTARGETDIR}/Headers/
+    ${MUXTARGETDIR}/Headers/ ${DEMUXTARGETDIR}/Headers/ \
+    ${SHARPYUVTARGETDIR}/Headers/
 
 if [[ ! -e ${SRCDIR}/configure ]]; then
   if ! (cd ${SRCDIR} && sh autogen.sh); then
@@ -133,18 +137,17 @@ for PLATFORM in ${PLATFORMS}; do
     CFLAGS="${CFLAGS}"
   set +x
 
-  # run make only in the src/ directory to create libwebp.a/libwebpdecoder.a
-  cd src/
-  make V=0
-  make install
+  # Build only the libraries, skip the examples.
+  make V=0 -C sharpyuv install
+  make V=0 -C src install
 
   LIBLIST+=" ${ROOTDIR}/lib/libwebp.a"
   DECLIBLIST+=" ${ROOTDIR}/lib/libwebpdecoder.a"
   MUXLIBLIST+=" ${ROOTDIR}/lib/libwebpmux.a"
   DEMUXLIBLIST+=" ${ROOTDIR}/lib/libwebpdemux.a"
+  SHARPYUVLIBLIST+=" ${ROOTDIR}/lib/libsharpyuv.a"
 
   make clean
-  cd ..
 
   export PATH=${OLDPATH}
 done
@@ -167,4 +170,9 @@ cp -a ${SRCDIR}/src/webp/{decode,types,mux_types,demux}.h \
     ${DEMUXTARGETDIR}/Headers/
 ${LIPO} -create ${DEMUXLIBLIST} -output ${DEMUXTARGETDIR}/WebPDemux
 
+echo "SHARPYUVLIBLIST = ${SHARPYUVLIBLIST}"
+cp -a ${SRCDIR}/sharpyuv/{sharpyuv,sharpyuv_csp}.h \
+    ${SHARPYUVTARGETDIR}/Headers/
+${LIPO} -create ${SHARPYUVLIBLIST} -output ${SHARPYUVTARGETDIR}/SharpYuv
+
 echo  "SUCCESS"

makefile.unix

@@ -3,7 +3,8 @@
 # It will not install the libraries system-wide, but just create the 'cwebp'
 # and 'dwebp' tools in the examples/ directory, along with the static
 # libraries 'src/libwebp.a', 'src/libwebpdecoder.a', 'src/mux/libwebpmux.a',
-# 'src/demux/libwebpdemux.a' and 'extras/libwebpextras.a'.
+# 'src/demux/libwebpdemux.a', 'extras/libwebpextras.a' and
+# 'sharpyuv/libsharpyuv.a'.
 #
 # To build the library and examples, use:
 #    make -f makefile.unix
@@ -36,13 +37,13 @@ else
 endif
 
 # SDL flags: use sdl-config if it exists
-SDL_CONFIG = $(shell sdl-config --version 2> /dev/null)
+SDL_CONFIG = $(shell sdl2-config --version 2> /dev/null)
 ifneq ($(SDL_CONFIG),)
-  SDL_LIBS = $(shell sdl-config --libs)
-  SDL_FLAGS = $(shell sdl-config --cflags)
+  SDL_LIBS = $(shell sdl2-config --libs)
+  SDL_FLAGS = $(shell sdl2-config --cflags)
 else
   # use best-guess
-  SDL_LIBS = -lSDL
+  SDL_LIBS = -lSDL2
   SDL_FLAGS =
 endif
 
@@ -125,6 +126,15 @@ endif
 ANIM_UTIL_OBJS = \
     examples/anim_util.o \
 
+SHARPYUV_OBJS = \
+    sharpyuv/sharpyuv.o \
+    sharpyuv/sharpyuv_cpu.o \
+    sharpyuv/sharpyuv_csp.o \
+    sharpyuv/sharpyuv_dsp.o \
+    sharpyuv/sharpyuv_gamma.o \
+    sharpyuv/sharpyuv_neon.o \
+    sharpyuv/sharpyuv_sse2.o \
+
 DEC_OBJS = \
     src/dec/alpha_dec.o \
     src/dec/buffer_dec.o \
@@ -266,6 +276,7 @@ UTILS_DEC_OBJS = \
     src/utils/color_cache_utils.o \
     src/utils/filters_utils.o \
     src/utils/huffman_utils.o \
+    src/utils/palette.o \
     src/utils/quant_levels_dec_utils.o \
     src/utils/random_utils.o \
     src/utils/rescaler_utils.o \
@@ -280,13 +291,15 @@ UTILS_ENC_OBJS = \
 EXTRA_OBJS = \
     extras/extras.o \
     extras/quality_estimate.o \
+    extras/sharpyuv_risk_table.o \
 
 LIBWEBPDECODER_OBJS = $(DEC_OBJS) $(DSP_DEC_OBJS) $(UTILS_DEC_OBJS)
-LIBWEBP_OBJS = $(LIBWEBPDECODER_OBJS) $(ENC_OBJS) $(DSP_ENC_OBJS) \
-               $(UTILS_ENC_OBJS)
+LIBWEBP_OBJS = $(LIBWEBPDECODER_OBJS) $(ENC_OBJS) \
+               $(DSP_ENC_OBJS) $(UTILS_ENC_OBJS)
 LIBWEBPMUX_OBJS = $(MUX_OBJS)
 LIBWEBPDEMUX_OBJS = $(DEMUX_OBJS)
 LIBWEBPEXTRA_OBJS = $(EXTRA_OBJS)
+LIBSHARPYUV_OBJS = $(SHARPYUV_OBJS)
 
 HDRS_INSTALLED = \
     src/webp/decode.h \
@@ -296,6 +309,11 @@ HDRS_INSTALLED = \
     src/webp/mux_types.h \
     src/webp/types.h \
 
+SHARPYUV_HDRS_INSTALLED = \
+    sharpyuv/sharpyuv.h \
+    sharpyuv/sharpyuv_cpu.h \
+    sharpyuv/sharpyuv_csp.h \
+
 HDRS = \
     src/dec/alphai_dec.h \
     src/dec/common_dec.h \
@@ -304,6 +322,7 @@ HDRS = \
     src/dec/vp8li_dec.h \
     src/dec/webpi_dec.h \
     src/dsp/common_sse2.h \
+    src/dsp/cpu.h \
     src/dsp/dsp.h \
     src/dsp/lossless.h \
     src/dsp/lossless_common.h \
@@ -326,6 +345,7 @@ HDRS = \
     src/utils/filters_utils.h \
     src/utils/huffman_utils.h \
     src/utils/huffman_encode_utils.h \
+    src/utils/palette.h \
     src/utils/quant_levels_utils.h \
     src/utils/quant_levels_dec_utils.h \
     src/utils/random_utils.h \
@@ -334,6 +354,7 @@ HDRS = \
     src/utils/utils.h \
     src/webp/format_constants.h \
     $(HDRS_INSTALLED) \
+    $(SHARPYUV_HDRS_INSTALLED) \
 
 OUT_LIBS = examples/libexample_util.a
 OUT_LIBS += imageio/libimageio_util.a
@@ -341,6 +362,7 @@ OUT_LIBS += imageio/libimagedec.a
 OUT_LIBS += imageio/libimageenc.a
 OUT_LIBS += src/libwebpdecoder.a
 OUT_LIBS += src/libwebp.a
+OUT_LIBS += sharpyuv/libsharpyuv.a
 EXTRA_LIB = extras/libwebpextras.a
 OUT_EXAMPLES = examples/cwebp examples/dwebp
 EXTRA_EXAMPLES = examples/gif2webp examples/vwebp examples/webpmux \
@@ -386,6 +408,7 @@ src/libwebpdecoder.a: $(LIBWEBPDECODER_OBJS)
 src/libwebp.a: $(LIBWEBP_OBJS)
 src/mux/libwebpmux.a: $(LIBWEBPMUX_OBJS)
 src/demux/libwebpdemux.a: $(LIBWEBPDEMUX_OBJS)
+sharpyuv/libsharpyuv.a: $(LIBSHARPYUV_OBJS)
 
 %.a:
 	$(AR) $(ARFLAGS) $@ $^
@@ -403,6 +426,7 @@ examples/webpinfo: examples/webpinfo.o
 examples/anim_diff: examples/libanim_util.a examples/libgifdec.a
 examples/anim_diff: src/demux/libwebpdemux.a examples/libexample_util.a
 examples/anim_diff: imageio/libimageio_util.a src/libwebp.a
+examples/anim_diff: sharpyuv/libsharpyuv.a
 examples/anim_diff: override EXTRA_LIBS += $(GIF_LIBS)
 examples/anim_diff: EXTRA_FLAGS += -DWEBP_HAVE_GIF
 examples/anim_dump: examples/libanim_util.a examples/libgifdec.a
@@ -411,12 +435,14 @@ examples/anim_dump: examples/libexample_util.a
 examples/anim_dump: imageio/libimageio_util.a
 examples/anim_dump: imageio/libimageenc.a
 examples/anim_dump: src/libwebp.a
+examples/anim_dump: sharpyuv/libsharpyuv.a
 examples/anim_dump: override EXTRA_LIBS += $(GIF_LIBS) $(DWEBP_LIBS)
 examples/cwebp: examples/libexample_util.a
 examples/cwebp: imageio/libimagedec.a
 examples/cwebp: src/demux/libwebpdemux.a
 examples/cwebp: imageio/libimageio_util.a
 examples/cwebp: src/libwebp.a
+examples/cwebp: sharpyuv/libsharpyuv.a
 examples/cwebp: override EXTRA_LIBS += $(CWEBP_LIBS)
 examples/dwebp: examples/libexample_util.a
 examples/dwebp: imageio/libimagedec.a
@@ -424,13 +450,16 @@ examples/dwebp: src/demux/libwebpdemux.a
 examples/dwebp: imageio/libimageenc.a
 examples/dwebp: imageio/libimageio_util.a
 examples/dwebp: src/libwebp.a
+examples/dwebp: sharpyuv/libsharpyuv.a
 examples/dwebp: override EXTRA_LIBS += $(DWEBP_LIBS)
 examples/gif2webp: examples/libexample_util.a imageio/libimageio_util.a
 examples/gif2webp: examples/libgifdec.a src/mux/libwebpmux.a src/libwebp.a
+examples/gif2webp: sharpyuv/libsharpyuv.a
 examples/gif2webp: override EXTRA_LIBS += $(GIF_LIBS)
 examples/gif2webp: EXTRA_FLAGS += -DWEBP_HAVE_GIF
 examples/vwebp: examples/libexample_util.a src/demux/libwebpdemux.a
 examples/vwebp: imageio/libimageio_util.a src/libwebp.a
+examples/vwebp: sharpyuv/libsharpyuv.a
 examples/vwebp: override EXTRA_LIBS += $(GL_LIBS)
 examples/vwebp: EXTRA_FLAGS += -DWEBP_HAVE_GL
 examples/webpmux: examples/libexample_util.a imageio/libimageio_util.a
@@ -438,7 +467,9 @@ examples/webpmux: src/mux/libwebpmux.a src/libwebpdecoder.a
 examples/img2webp: examples/libexample_util.a imageio/libimageio_util.a
 examples/img2webp: imageio/libimagedec.a
 examples/img2webp: src/demux/libwebpdemux.a
-examples/img2webp: src/mux/libwebpmux.a src/libwebp.a
+examples/img2webp: src/mux/libwebpmux.a
+examples/img2webp: src/libwebp.a
+examples/img2webp: sharpyuv/libsharpyuv.a
 examples/img2webp: override EXTRA_LIBS += $(CWEBP_LIBS)
 examples/webpinfo: examples/libexample_util.a imageio/libimageio_util.a
 examples/webpinfo: src/libwebpdecoder.a
@@ -448,16 +479,19 @@ extras/get_disto: imageio/libimagedec.a
 extras/get_disto: src/demux/libwebpdemux.a
 extras/get_disto: imageio/libimageio_util.a
 extras/get_disto: src/libwebp.a
+extras/get_disto: sharpyuv/libsharpyuv.a
 extras/get_disto: override EXTRA_LIBS += $(CWEBP_LIBS)
 
 extras/webp_quality: extras/webp_quality.o
 extras/webp_quality: imageio/libimageio_util.a
 extras/webp_quality: $(EXTRA_LIB) src/libwebp.a
+extras/webp_quality: sharpyuv/libsharpyuv.a
 
 extras/vwebp_sdl: extras/vwebp_sdl.o
 extras/vwebp_sdl: extras/webp_to_sdl.o
 extras/vwebp_sdl: imageio/libimageio_util.a
 extras/vwebp_sdl: src/libwebp.a
+extras/vwebp_sdl: sharpyuv/libsharpyuv.a
 extras/vwebp_sdl: EXTRA_FLAGS += -DWEBP_HAVE_SDL $(SDL_FLAGS)
 extras/vwebp_sdl: override EXTRA_LIBS += $(SDL_LIBS)
 
@@ -468,12 +502,15 @@ dist: DESTDIR := dist
 dist: OUT_EXAMPLES += $(EXTRA_EXAMPLES)
 dist: all
 	$(INSTALL) -m755 -d $(DESTDIR)/include/webp \
-	           $(DESTDIR)/bin $(DESTDIR)/doc $(DESTDIR)/lib
+	            $(DESTDIR)/include/webp/sharpyuv \
+	            $(DESTDIR)/bin $(DESTDIR)/doc $(DESTDIR)/lib
 	$(INSTALL) -m755 -s $(OUT_EXAMPLES) $(DESTDIR)/bin
 	$(INSTALL) -m644 $(HDRS_INSTALLED) $(DESTDIR)/include/webp
+	$(INSTALL) -m644 $(SHARPYUV_HDRS_INSTALLED) $(DESTDIR)/include/webp/sharpyuv
 	$(INSTALL) -m644 src/libwebp.a $(DESTDIR)/lib
 	$(INSTALL) -m644 src/demux/libwebpdemux.a $(DESTDIR)/lib
 	$(INSTALL) -m644 src/mux/libwebpmux.a $(DESTDIR)/lib
+	$(INSTALL) -m644 sharpyuv/libsharpyuv.a $(DESTDIR)/lib
 	umask 022; \
 	for m in man/[cdv]webp.1 man/gif2webp.1 man/webpmux.1 \
                  man/img2webp.1 man/webpinfo.1; do \
@@ -489,6 +526,7 @@ clean:
               examples/*.o examples/*~ \
               extras/*.o extras/*~ \
               imageio/*.o imageio/*~ \
+              sharpyuv/*.o sharpyuv/*~ \
               src/dec/*.o src/dec/*~ \
               src/demux/*.o src/demux/*~ \
               src/dsp/*.o src/dsp/*~ \

man/cwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH CWEBP 1 "November 17, 2021"
+.TH CWEBP 1 "September 17, 2024"
 .SH NAME
 cwebp \- compress an image file to a WebP file
 .SH SYNOPSIS
@@ -90,15 +90,17 @@ additional encoding possibilities and decide on the quality gain.
 Lower value can result in faster processing time at the expense of
 larger file size and lower compression quality.
 .TP
-.BI \-resize " width height
-Resize the source to a rectangle with size \fBwidth\fP x \fBheight\fP.
-If either (but not both) of the \fBwidth\fP or \fBheight\fP parameters is 0,
-the value will be calculated preserving the aspect\-ratio.
-.TP
 .BI \-crop " x_position y_position width height
 Crop the source to a rectangle with top\-left corner at coordinates
 (\fBx_position\fP, \fBy_position\fP) and size \fBwidth\fP x \fBheight\fP.
 This cropping area must be fully contained within the source rectangle.
+Note: the cropping is applied \fIbefore\fP any scaling.
+.TP
+.BI \-resize " width height
+Resize the source to a rectangle with size \fBwidth\fP x \fBheight\fP.
+If either (but not both) of the \fBwidth\fP or \fBheight\fP parameters is 0,
+the value will be calculated preserving the aspect\-ratio. Note: scaling
+is applied \fIafter\fP cropping.
 .TP
 .B \-mt
 Use multi\-threading for encoding, if possible.
@@ -133,7 +135,9 @@ are used, \fB\-size\fP value will prevail.
 Set a maximum number of passes to use during the dichotomy used by
 options \fB\-size\fP or \fB\-psnr\fP. Maximum value is 10, default is 1.
 If options \fB\-size\fP or \fB\-psnr\fP were used, but \fB\-pass\fP wasn't
-specified, a default value of '6' passes will be used.
+specified, a default value of '6' passes will be used. If \fB\-pass\fP is
+specified, but neither \fB-size\fP nor \fB-psnr\fP are, a target PSNR of 40dB
+will be used.
 .TP
 .BI \-qrange " int int
 Specifies the permissible interval for the quality factor. This is particularly
@@ -176,8 +180,8 @@ Disable strong filtering (if filtering is being used thanks to the
 \fB\-f\fP option) and use simple filtering instead.
 .TP
 .B \-sharp_yuv
-Use more accurate and sharper RGB->YUV conversion if needed. Note that this
-process is slower than the default 'fast' RGB->YUV conversion.
+Use more accurate and sharper RGB->YUV conversion. Note that this process is
+slower than the default 'fast' RGB->YUV conversion.
 .TP
 .BI \-sns " int
 Specify the amplitude of the spatial noise shaping. Spatial noise shaping
@@ -200,7 +204,8 @@ In the VP8 format, the so\-called control partition has a limit of 512k and
 is used to store the following information: whether the macroblock is skipped,
 which segment it belongs to, whether it is coded as intra 4x4 or intra 16x16
 mode, and finally the prediction modes to use for each of the sub\-blocks.
-For a very large image, 512k only leaves room to few bits per 16x16 macroblock.
+For a very large image, 512k only leaves room for a few bits per 16x16
+macroblock.
 The absolute minimum is 4 bits per macroblock. Skip, segment, and mode
 information can use up almost all these 4 bits (although the case is unlikely),
 which is problematic for very large images. The partition_limit factor controls
@@ -209,7 +214,8 @@ useful in case the 512k limit is reached and the following message is displayed:
 \fIError code: 6 (PARTITION0_OVERFLOW: Partition #0 is too big to fit 512k)\fP.
 If using \fB\-partition_limit\fP is not enough to meet the 512k constraint, one
 should use less segments in order to save more header bits per macroblock.
-See the \fB\-segments\fP option.
+See the \fB\-segments\fP option. Note the \fB-m\fP and \fB-q\fP options also
+influence the encoder's decisions and ability to hit this limit.
 
 .SS LOGGING OPTIONS
 These options control the level of output:
@@ -293,12 +299,12 @@ Note: each input format may not support all combinations.
 .B \-noasm
 Disable all assembly optimizations.
 
-.SH BUGS
-Please report all bugs to the issue tracker:
-https://bugs.chromium.org/p/webp
-.br
-Patches welcome! See this page to get started:
-https://www.webmproject.org/code/contribute/submitting\-patches/
+.SH EXIT STATUS
+If there were no problems during execution, \fBcwebp\fP exits with the value of
+the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBcwebp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
 
 .SH EXAMPLES
 cwebp \-q 50 -lossless picture.png \-o picture_lossless.webp
@@ -318,6 +324,13 @@ https://chromium.googlesource.com/webm/libwebp
 This manual page was written by Pascal Massimino <pascal.massimino@gmail.com>,
 for the Debian project (and may be used by others).
 
+.SH REPORTING BUGS
+Please report all bugs to the issue tracker:
+https://issues.webmproject.org
+.br
+Patches welcome! See this page to get started:
+https://www.webmproject.org/code/contribute/submitting\-patches/
+
 .SH SEE ALSO
 .BR dwebp (1),
 .BR gif2webp (1)

man/dwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH DWEBP 1 "November 17, 2021"
+.TH DWEBP 1 "July 18, 2024"
 .SH NAME
 dwebp \- decompress a WebP file to an image file
 .SH SYNOPSIS
@@ -108,12 +108,12 @@ Print extra information (decoding time in particular).
 .B \-noasm
 Disable all assembly optimizations.
 
-.SH BUGS
-Please report all bugs to the issue tracker:
-https://bugs.chromium.org/p/webp
-.br
-Patches welcome! See this page to get started:
-https://www.webmproject.org/code/contribute/submitting\-patches/
+.SH EXIT STATUS
+If there were no problems during execution, \fBdwebp\fP exits with the value of
+the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBdwebp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
 
 .SH EXAMPLES
 dwebp picture.webp \-o output.png
@@ -133,6 +133,13 @@ https://chromium.googlesource.com/webm/libwebp
 This manual page was written by Pascal Massimino <pascal.massimino@gmail.com>,
 for the Debian project (and may be used by others).
 
+.SH REPORTING BUGS
+Please report all bugs to the issue tracker:
+https://issues.webmproject.org
+.br
+Patches welcome! See this page to get started:
+https://www.webmproject.org/code/contribute/submitting\-patches/
+
 .SH SEE ALSO
 .BR cwebp (1),
 .BR gif2webp (1),

man/gif2webp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH GIF2WEBP 1 "November 17, 2021"
+.TH GIF2WEBP 1 "July 18, 2024"
 .SH NAME
 gif2webp \- Convert a GIF image to WebP
 .SH SYNOPSIS
@@ -126,12 +126,12 @@ Print extra information.
 .B \-quiet
 Do not print anything.
 
-.SH BUGS
-Please report all bugs to the issue tracker:
-https://bugs.chromium.org/p/webp
-.br
-Patches welcome! See this page to get started:
-https://www.webmproject.org/code/contribute/submitting\-patches/
+.SH EXIT STATUS
+If there were no problems during execution, \fBgif2webp\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBgif2webp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
 
 .SH EXAMPLES
 gif2webp picture.gif \-o picture.webp
@@ -155,6 +155,13 @@ https://chromium.googlesource.com/webm/libwebp
 This manual page was written by Urvang Joshi <urvang@google.com>, for the
 Debian project (and may be used by others).
 
+.SH REPORTING BUGS
+Please report all bugs to the issue tracker:
+https://issues.webmproject.org
+.br
+Patches welcome! See this page to get started:
+https://www.webmproject.org/code/contribute/submitting\-patches/
+
 .SH SEE ALSO
 .BR cwebp (1),
 .BR dwebp (1),

man/img2webp.1

@@ -1,10 +1,10 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH IMG2WEBP 1 "January 5, 2022"
+.TH IMG2WEBP 1 "September 17, 2024"
 .SH NAME
 img2webp \- create animated WebP file from a sequence of input images.
 .SH SYNOPSIS
 .B img2webp
-[file_options] [[frame_options] frame_file]...
+[file_options] [[frame_options] frame_file]... [\-o webp_file]
 .br
 .B img2webp argument_file_name
 .br
@@ -44,6 +44,18 @@ Mixed compression mode: optimize compression of the image by picking either
 lossy or lossless compression for each frame heuristically. This global
 option disables the local option \fB-lossy\fP and \fB-lossless\fP .
 .TP
+.BI \-near_lossless " int
+Specify the level of near\-lossless image preprocessing. This option adjusts
+pixel values to help compressibility, but has minimal impact on the visual
+quality. It triggers lossless compression mode automatically. The range is 0
+(maximum preprocessing) to 100 (no preprocessing, the default). The typical
+value is around 60. Note that lossy with \fB\-q 100\fP can at times yield
+better results.
+.TP
+.B \-sharp_yuv
+Use more accurate and sharper RGB->YUV conversion. Note that this process is
+slower than the default 'fast' RGB->YUV conversion.
+.TP
 .BI \-loop " int
 Specifies the number of times the animation should loop. Using '0'
 means 'loop indefinitely'.
@@ -76,18 +88,23 @@ Specify the compression factor between 0 and 100. The default is 75.
 Specify the compression method to use. This parameter controls the
 trade off between encoding speed and the compressed file size and quality.
 Possible values range from 0 to 6. Default value is 4.
+.TP
+.B \-exact, \-noexact
+Preserve or alter RGB values in transparent area. The default is
+\fB-noexact\fP, to help compressibility. Note \fB\-noexact\fP may cause
+artifacts in frames compressed with \fB\-lossy\fP.
+
+.SH EXIT STATUS
+If there were no problems during execution, \fBimg2webp\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBimg2webp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
 
 .SH EXAMPLE
 img2webp -loop 2 in0.png -lossy in1.jpg -d 80 in2.tiff -o out.webp
 .br
 
-.SH BUGS
-Please report all bugs to the issue tracker:
-https://bugs.chromium.org/p/webp
-.br
-Patches welcome! See this page to get started:
-https://www.webmproject.org/code/contribute/submitting\-patches/
-
 .SH AUTHORS
 \fBimg2webp\fP is a part of libwebp and was written by the WebP team.
 .br
@@ -97,6 +114,13 @@ https://chromium.googlesource.com/webm/libwebp
 This manual page was written by Pascal Massimino <pascal.massimino@gmail.com>,
 for the Debian project (and may be used by others).
 
+.SH REPORTING BUGS
+Please report all bugs to the issue tracker:
+https://issues.webmproject.org
+.br
+Patches welcome! See this page to get started:
+https://www.webmproject.org/code/contribute/submitting\-patches/
+
 .SH SEE ALSO
 .BR webpmux (1),
 .BR gif2webp (1)

man/vwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH VWEBP 1 "November 17, 2021"
+.TH VWEBP 1 "July 18, 2024"
 .SH NAME
 vwebp \- decompress a WebP file and display it in a window
 .SH SYNOPSIS
@@ -72,12 +72,12 @@ Disable blending and disposal process, for debugging purposes.
 .B 'q' / 'Q' / ESC
 Quit.
 
-.SH BUGS
-Please report all bugs to the issue tracker:
-https://bugs.chromium.org/p/webp
-.br
-Patches welcome! See this page to get started:
-https://www.webmproject.org/code/contribute/submitting\-patches/
+.SH EXIT STATUS
+If there were no problems during execution, \fBvwebp\fP exits with the value of
+the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBvwebp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
 
 .SH EXAMPLES
 vwebp picture.webp
@@ -94,6 +94,13 @@ https://chromium.googlesource.com/webm/libwebp
 .PP
 This manual page was written for the Debian project (and may be used by others).
 
+.SH REPORTING BUGS
+Please report all bugs to the issue tracker:
+https://issues.webmproject.org
+.br
+Patches welcome! See this page to get started:
+https://www.webmproject.org/code/contribute/submitting\-patches/
+
 .SH SEE ALSO
 .BR dwebp (1)
 .br

man/webpinfo.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH WEBPINFO 1 "November 17, 2021"
+.TH WEBPINFO 1 "July 18, 2024"
 .SH NAME
 webpinfo \- print out the chunk level structure of WebP files
 along with basic integrity checks.
@@ -47,12 +47,12 @@ Detailed usage instructions.
 Input files in WebP format. Input files must come last, following
 options (if any). There can be multiple input files.
 
-.SH BUGS
-Please report all bugs to the issue tracker:
-https://bugs.chromium.org/p/webp
-.br
-Patches welcome! See this page to get started:
-https://www.webmproject.org/code/contribute/submitting\-patches/
+.SH EXIT STATUS
+If there were no problems during execution, \fBwebpinfo\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBwebpinfo\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
 
 .SH EXAMPLES
 .br
@@ -73,6 +73,13 @@ https://chromium.googlesource.com/webm/libwebp
 This manual page was written by Hui Su <huisu@google.com>,
 for the Debian project (and may be used by others).
 
+.SH REPORTING BUGS
+Please report all bugs to the issue tracker:
+https://issues.webmproject.org
+.br
+Patches welcome! See this page to get started:
+https://www.webmproject.org/code/contribute/submitting\-patches/
+
 .SH SEE ALSO
 .BR webpmux (1)
 .br

man/webpmux.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH WEBPMUX 1 "November 17, 2021"
+.TH WEBPMUX 1 "July 18, 2024"
 .SH NAME
 webpmux \- create animated WebP files from non\-animated WebP images, extract
 frames from animated WebP images, and manage XMP/EXIF metadata and ICC profile.
@@ -186,12 +186,12 @@ Output file in WebP format.
 .TP
 The nature of EXIF, XMP and ICC data is not checked and is assumed to be valid.
 
-.SH BUGS
-Please report all bugs to the issue tracker:
-https://bugs.chromium.org/p/webp
-.br
-Patches welcome! See this page to get started:
-https://www.webmproject.org/code/contribute/submitting\-patches/
+.SH EXIT STATUS
+If there were no problems during execution, \fBwebpmux\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBwebpmux\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
 
 .SH EXAMPLES
 .P
@@ -262,6 +262,13 @@ https://chromium.googlesource.com/webm/libwebp
 This manual page was written by Vikas Arora <vikaas.arora@gmail.com>,
 for the Debian project (and may be used by others).
 
+.SH REPORTING BUGS
+Please report all bugs to the issue tracker:
+https://issues.webmproject.org
+.br
+Patches welcome! See this page to get started:
+https://www.webmproject.org/code/contribute/submitting\-patches/
+
 .SH SEE ALSO
 .BR cwebp (1),
 .BR dwebp (1),

sharpyuv/Makefile.am

@@ -0,0 +1,41 @@
+AM_CPPFLAGS += -I$(top_builddir) -I$(top_srcdir)
+AM_CPPFLAGS += -I$(top_builddir)/src -I$(top_srcdir)/src
+
+lib_LTLIBRARIES = libsharpyuv.la
+
+noinst_LTLIBRARIES =
+noinst_LTLIBRARIES += libsharpyuv_sse2.la
+noinst_LTLIBRARIES += libsharpyuv_neon.la
+
+libsharpyuvinclude_HEADERS =
+libsharpyuvinclude_HEADERS += sharpyuv.h
+libsharpyuvinclude_HEADERS += sharpyuv_csp.h
+noinst_HEADERS =
+noinst_HEADERS += ../src/dsp/cpu.c
+noinst_HEADERS += ../src/dsp/cpu.h
+noinst_HEADERS += ../src/webp/types.h
+
+libsharpyuv_sse2_la_SOURCES =
+libsharpyuv_sse2_la_SOURCES += sharpyuv_sse2.c
+libsharpyuv_sse2_la_CPPFLAGS = $(libsharpyuv_la_CPPFLAGS)
+libsharpyuv_sse2_la_CFLAGS = $(AM_CFLAGS) $(SSE2_FLAGS)
+
+libsharpyuv_neon_la_SOURCES =
+libsharpyuv_neon_la_SOURCES += sharpyuv_neon.c
+libsharpyuv_neon_la_CPPFLAGS = $(libsharpyuv_la_CPPFLAGS)
+libsharpyuv_neon_la_CFLAGS = $(AM_CFLAGS) $(NEON_FLAGS)
+
+libsharpyuv_la_SOURCES =
+libsharpyuv_la_SOURCES += sharpyuv_cpu.c sharpyuv_cpu.h
+libsharpyuv_la_SOURCES += sharpyuv_csp.c sharpyuv_csp.h
+libsharpyuv_la_SOURCES += sharpyuv_dsp.c sharpyuv_dsp.h
+libsharpyuv_la_SOURCES += sharpyuv_gamma.c sharpyuv_gamma.h
+libsharpyuv_la_SOURCES += sharpyuv.c sharpyuv.h
+
+libsharpyuv_la_CPPFLAGS = $(AM_CPPFLAGS)
+libsharpyuv_la_LDFLAGS = -no-undefined -version-info 1:0:1 -lm
+libsharpyuv_la_LIBADD =
+libsharpyuv_la_LIBADD += libsharpyuv_sse2.la
+libsharpyuv_la_LIBADD += libsharpyuv_neon.la
+libsharpyuvincludedir = $(includedir)/webp/sharpyuv
+pkgconfig_DATA = libsharpyuv.pc

sharpyuv/libsharpyuv.pc.in

@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@/webp
+
+Name: libsharpyuv
+Description: Library for sharp RGB to YUV conversion
+Version: @PACKAGE_VERSION@
+Cflags: -I${includedir}
+Libs: -L${libdir} -l@webp_libname_prefix@sharpyuv
+Libs.private: -lm @PTHREAD_CFLAGS@ @PTHREAD_LIBS@

sharpyuv/libsharpyuv.rc

@@ -0,0 +1,41 @@
+#define APSTUDIO_READONLY_SYMBOLS
+#include "winres.h"
+#undef APSTUDIO_READONLY_SYMBOLS
+
+#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
+LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
+
+VS_VERSION_INFO VERSIONINFO
+ FILEVERSION 0,0,4,0
+ PRODUCTVERSION 0,0,4,0
+ FILEFLAGSMASK 0x3fL
+#ifdef _DEBUG
+ FILEFLAGS 0x1L
+#else
+ FILEFLAGS 0x0L
+#endif
+ FILEOS 0x40004L
+ FILETYPE 0x2L
+ FILESUBTYPE 0x0L
+BEGIN
+    BLOCK "StringFileInfo"
+    BEGIN
+        BLOCK "040904b0"
+        BEGIN
+            VALUE "CompanyName", "Google, Inc."
+            VALUE "FileDescription", "libsharpyuv DLL"
+            VALUE "FileVersion", "0.4.0"
+            VALUE "InternalName", "libsharpyuv.dll"
+            VALUE "LegalCopyright", "Copyright (C) 2024"
+            VALUE "OriginalFilename", "libsharpyuv.dll"
+            VALUE "ProductName", "SharpYuv Library"
+            VALUE "ProductVersion", "0.4.0"
+        END
+    END
+    BLOCK "VarFileInfo"
+    BEGIN
+        VALUE "Translation", 0x409, 1200
+    END
+END
+
+#endif    // English (United States) resources

sharpyuv/sharpyuv.c

@@ -0,0 +1,575 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Sharp RGB to YUV conversion.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "sharpyuv/sharpyuv.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "src/webp/types.h"
+#include "sharpyuv/sharpyuv_cpu.h"
+#include "sharpyuv/sharpyuv_dsp.h"
+#include "sharpyuv/sharpyuv_gamma.h"
+
+//------------------------------------------------------------------------------
+
+int SharpYuvGetVersion(void) {
+  return SHARPYUV_VERSION;
+}
+
+//------------------------------------------------------------------------------
+// Sharp RGB->YUV conversion
+
+static const int kNumIterations = 4;
+
+#define YUV_FIX 16  // fixed-point precision for RGB->YUV
+static const int kYuvHalf = 1 << (YUV_FIX - 1);
+
+// Max bit depth so that intermediate calculations fit in 16 bits.
+static const int kMaxBitDepth = 14;
+
+// Returns the precision shift to use based on the input rgb_bit_depth.
+static int GetPrecisionShift(int rgb_bit_depth) {
+  // Try to add 2 bits of precision if it fits in kMaxBitDepth. Otherwise remove
+  // bits if needed.
+  return ((rgb_bit_depth + 2) <= kMaxBitDepth) ? 2
+                                               : (kMaxBitDepth - rgb_bit_depth);
+}
+
+typedef int16_t fixed_t;      // signed type with extra precision for UV
+typedef uint16_t fixed_y_t;   // unsigned type with extra precision for W
+
+//------------------------------------------------------------------------------
+
+static uint8_t clip_8b(fixed_t v) {
+  return (!(v & ~0xff)) ? (uint8_t)v : (v < 0) ? 0u : 255u;
+}
+
+static uint16_t clip(fixed_t v, int max) {
+  return (v < 0) ? 0 : (v > max) ? max : (uint16_t)v;
+}
+
+static fixed_y_t clip_bit_depth(int y, int bit_depth) {
+  const int max = (1 << bit_depth) - 1;
+  return (!(y & ~max)) ? (fixed_y_t)y : (y < 0) ? 0 : max;
+}
+
+//------------------------------------------------------------------------------
+
+static int RGBToGray(int64_t r, int64_t g, int64_t b) {
+  const int64_t luma = 13933 * r + 46871 * g + 4732 * b + kYuvHalf;
+  return (int)(luma >> YUV_FIX);
+}
+
+static uint32_t ScaleDown(uint16_t a, uint16_t b, uint16_t c, uint16_t d,
+                          int rgb_bit_depth,
+                          SharpYuvTransferFunctionType transfer_type) {
+  const int bit_depth = rgb_bit_depth + GetPrecisionShift(rgb_bit_depth);
+  const uint32_t A = SharpYuvGammaToLinear(a, bit_depth, transfer_type);
+  const uint32_t B = SharpYuvGammaToLinear(b, bit_depth, transfer_type);
+  const uint32_t C = SharpYuvGammaToLinear(c, bit_depth, transfer_type);
+  const uint32_t D = SharpYuvGammaToLinear(d, bit_depth, transfer_type);
+  return SharpYuvLinearToGamma((A + B + C + D + 2) >> 2, bit_depth,
+                               transfer_type);
+}
+
+static WEBP_INLINE void UpdateW(const fixed_y_t* src, fixed_y_t* dst, int w,
+                                int rgb_bit_depth,
+                                SharpYuvTransferFunctionType transfer_type) {
+  const int bit_depth = rgb_bit_depth + GetPrecisionShift(rgb_bit_depth);
+  int i = 0;
+  do {
+    const uint32_t R =
+        SharpYuvGammaToLinear(src[0 * w + i], bit_depth, transfer_type);
+    const uint32_t G =
+        SharpYuvGammaToLinear(src[1 * w + i], bit_depth, transfer_type);
+    const uint32_t B =
+        SharpYuvGammaToLinear(src[2 * w + i], bit_depth, transfer_type);
+    const uint32_t Y = RGBToGray(R, G, B);
+    dst[i] = (fixed_y_t)SharpYuvLinearToGamma(Y, bit_depth, transfer_type);
+  } while (++i < w);
+}
+
+static void UpdateChroma(const fixed_y_t* src1, const fixed_y_t* src2,
+                         fixed_t* dst, int uv_w, int rgb_bit_depth,
+                         SharpYuvTransferFunctionType transfer_type) {
+  int i = 0;
+  do {
+    const int r =
+        ScaleDown(src1[0 * uv_w + 0], src1[0 * uv_w + 1], src2[0 * uv_w + 0],
+                  src2[0 * uv_w + 1], rgb_bit_depth, transfer_type);
+    const int g =
+        ScaleDown(src1[2 * uv_w + 0], src1[2 * uv_w + 1], src2[2 * uv_w + 0],
+                  src2[2 * uv_w + 1], rgb_bit_depth, transfer_type);
+    const int b =
+        ScaleDown(src1[4 * uv_w + 0], src1[4 * uv_w + 1], src2[4 * uv_w + 0],
+                  src2[4 * uv_w + 1], rgb_bit_depth, transfer_type);
+    const int W = RGBToGray(r, g, b);
+    dst[0 * uv_w] = (fixed_t)(r - W);
+    dst[1 * uv_w] = (fixed_t)(g - W);
+    dst[2 * uv_w] = (fixed_t)(b - W);
+    dst  += 1;
+    src1 += 2;
+    src2 += 2;
+  } while (++i < uv_w);
+}
+
+static void StoreGray(const fixed_y_t* rgb, fixed_y_t* y, int w) {
+  int i = 0;
+  assert(w > 0);
+  do {
+    y[i] = RGBToGray(rgb[0 * w + i], rgb[1 * w + i], rgb[2 * w + i]);
+  } while (++i < w);
+}
+
+//------------------------------------------------------------------------------
+
+static WEBP_INLINE fixed_y_t Filter2(int A, int B, int W0, int bit_depth) {
+  const int v0 = (A * 3 + B + 2) >> 2;
+  return clip_bit_depth(v0 + W0, bit_depth);
+}
+
+//------------------------------------------------------------------------------
+
+static WEBP_INLINE int Shift(int v, int shift) {
+  return (shift >= 0) ? (v << shift) : (v >> -shift);
+}
+
+static void ImportOneRow(const uint8_t* const r_ptr,
+                         const uint8_t* const g_ptr,
+                         const uint8_t* const b_ptr,
+                         int rgb_step,
+                         int rgb_bit_depth,
+                         int pic_width,
+                         fixed_y_t* const dst) {
+  // Convert the rgb_step from a number of bytes to a number of uint8_t or
+  // uint16_t values depending the bit depth.
+  const int step = (rgb_bit_depth > 8) ? rgb_step / 2 : rgb_step;
+  int i = 0;
+  const int w = (pic_width + 1) & ~1;
+  do {
+    const int off = i * step;
+    const int shift = GetPrecisionShift(rgb_bit_depth);
+    if (rgb_bit_depth == 8) {
+      dst[i + 0 * w] = Shift(r_ptr[off], shift);
+      dst[i + 1 * w] = Shift(g_ptr[off], shift);
+      dst[i + 2 * w] = Shift(b_ptr[off], shift);
+    } else {
+      dst[i + 0 * w] = Shift(((uint16_t*)r_ptr)[off], shift);
+      dst[i + 1 * w] = Shift(((uint16_t*)g_ptr)[off], shift);
+      dst[i + 2 * w] = Shift(((uint16_t*)b_ptr)[off], shift);
+    }
+  } while (++i < pic_width);
+  if (pic_width & 1) {  // replicate rightmost pixel
+    dst[pic_width + 0 * w] = dst[pic_width + 0 * w - 1];
+    dst[pic_width + 1 * w] = dst[pic_width + 1 * w - 1];
+    dst[pic_width + 2 * w] = dst[pic_width + 2 * w - 1];
+  }
+}
+
+static void InterpolateTwoRows(const fixed_y_t* const best_y,
+                               const fixed_t* prev_uv,
+                               const fixed_t* cur_uv,
+                               const fixed_t* next_uv,
+                               int w,
+                               fixed_y_t* out1,
+                               fixed_y_t* out2,
+                               int rgb_bit_depth) {
+  const int uv_w = w >> 1;
+  const int len = (w - 1) >> 1;   // length to filter
+  int k = 3;
+  const int bit_depth = rgb_bit_depth + GetPrecisionShift(rgb_bit_depth);
+  while (k-- > 0) {   // process each R/G/B segments in turn
+    // special boundary case for i==0
+    out1[0] = Filter2(cur_uv[0], prev_uv[0], best_y[0], bit_depth);
+    out2[0] = Filter2(cur_uv[0], next_uv[0], best_y[w], bit_depth);
+
+    SharpYuvFilterRow(cur_uv, prev_uv, len, best_y + 0 + 1, out1 + 1,
+                      bit_depth);
+    SharpYuvFilterRow(cur_uv, next_uv, len, best_y + w + 1, out2 + 1,
+                      bit_depth);
+
+    // special boundary case for i == w - 1 when w is even
+    if (!(w & 1)) {
+      out1[w - 1] = Filter2(cur_uv[uv_w - 1], prev_uv[uv_w - 1],
+                            best_y[w - 1 + 0], bit_depth);
+      out2[w - 1] = Filter2(cur_uv[uv_w - 1], next_uv[uv_w - 1],
+                            best_y[w - 1 + w], bit_depth);
+    }
+    out1 += w;
+    out2 += w;
+    prev_uv += uv_w;
+    cur_uv  += uv_w;
+    next_uv += uv_w;
+  }
+}
+
+static WEBP_INLINE int RGBToYUVComponent(int r, int g, int b,
+                                         const int coeffs[4], int sfix) {
+  const int srounder = 1 << (YUV_FIX + sfix - 1);
+  const int luma = coeffs[0] * r + coeffs[1] * g + coeffs[2] * b +
+                   coeffs[3] + srounder;
+  return (luma >> (YUV_FIX + sfix));
+}
+
+static int ConvertWRGBToYUV(const fixed_y_t* best_y, const fixed_t* best_uv,
+                            uint8_t* y_ptr, int y_stride, uint8_t* u_ptr,
+                            int u_stride, uint8_t* v_ptr, int v_stride,
+                            int rgb_bit_depth,
+                            int yuv_bit_depth, int width, int height,
+                            const SharpYuvConversionMatrix* yuv_matrix) {
+  int i, j;
+  const fixed_t* const best_uv_base = best_uv;
+  const int w = (width + 1) & ~1;
+  const int h = (height + 1) & ~1;
+  const int uv_w = w >> 1;
+  const int uv_h = h >> 1;
+  const int sfix = GetPrecisionShift(rgb_bit_depth);
+  const int yuv_max = (1 << yuv_bit_depth) - 1;
+
+  best_uv = best_uv_base;
+  j = 0;
+  do {
+    i = 0;
+    do {
+      const int off = (i >> 1);
+      const int W = best_y[i];
+      const int r = best_uv[off + 0 * uv_w] + W;
+      const int g = best_uv[off + 1 * uv_w] + W;
+      const int b = best_uv[off + 2 * uv_w] + W;
+      const int y = RGBToYUVComponent(r, g, b, yuv_matrix->rgb_to_y, sfix);
+      if (yuv_bit_depth <= 8) {
+        y_ptr[i] = clip_8b(y);
+      } else {
+        ((uint16_t*)y_ptr)[i] = clip(y, yuv_max);
+      }
+    } while (++i < width);
+    best_y += w;
+    best_uv += (j & 1) * 3 * uv_w;
+    y_ptr += y_stride;
+  } while (++j < height);
+
+  best_uv = best_uv_base;
+  j = 0;
+  do {
+    i = 0;
+    do {
+      // Note r, g and b values here are off by W, but a constant offset on all
+      // 3 components doesn't change the value of u and v with a YCbCr matrix.
+      const int r = best_uv[i + 0 * uv_w];
+      const int g = best_uv[i + 1 * uv_w];
+      const int b = best_uv[i + 2 * uv_w];
+      const int u = RGBToYUVComponent(r, g, b, yuv_matrix->rgb_to_u, sfix);
+      const int v = RGBToYUVComponent(r, g, b, yuv_matrix->rgb_to_v, sfix);
+      if (yuv_bit_depth <= 8) {
+        u_ptr[i] = clip_8b(u);
+        v_ptr[i] = clip_8b(v);
+      } else {
+        ((uint16_t*)u_ptr)[i] = clip(u, yuv_max);
+        ((uint16_t*)v_ptr)[i] = clip(v, yuv_max);
+      }
+    } while (++i < uv_w);
+    best_uv += 3 * uv_w;
+    u_ptr += u_stride;
+    v_ptr += v_stride;
+  } while (++j < uv_h);
+  return 1;
+}
+
+//------------------------------------------------------------------------------
+// Main function
+
+static void* SafeMalloc(uint64_t nmemb, size_t size) {
+  const uint64_t total_size = nmemb * (uint64_t)size;
+  if (total_size != (size_t)total_size) return NULL;
+  return malloc((size_t)total_size);
+}
+
+#define SAFE_ALLOC(W, H, T) ((T*)SafeMalloc((uint64_t)(W) * (H), sizeof(T)))
+
+static int DoSharpArgbToYuv(const uint8_t* r_ptr, const uint8_t* g_ptr,
+                            const uint8_t* b_ptr, int rgb_step, int rgb_stride,
+                            int rgb_bit_depth, uint8_t* y_ptr, int y_stride,
+                            uint8_t* u_ptr, int u_stride, uint8_t* v_ptr,
+                            int v_stride, int yuv_bit_depth, int width,
+                            int height,
+                            const SharpYuvConversionMatrix* yuv_matrix,
+                            SharpYuvTransferFunctionType transfer_type) {
+  // we expand the right/bottom border if needed
+  const int w = (width + 1) & ~1;
+  const int h = (height + 1) & ~1;
+  const int uv_w = w >> 1;
+  const int uv_h = h >> 1;
+  const int y_bit_depth = rgb_bit_depth + GetPrecisionShift(rgb_bit_depth);
+  uint64_t prev_diff_y_sum = ~0;
+  int j, iter;
+
+  // TODO(skal): allocate one big memory chunk. But for now, it's easier
+  // for valgrind debugging to have several chunks.
+  fixed_y_t* const tmp_buffer = SAFE_ALLOC(w * 3, 2, fixed_y_t);   // scratch
+  fixed_y_t* const best_y_base = SAFE_ALLOC(w, h, fixed_y_t);
+  fixed_y_t* const target_y_base = SAFE_ALLOC(w, h, fixed_y_t);
+  fixed_y_t* const best_rgb_y = SAFE_ALLOC(w, 2, fixed_y_t);
+  fixed_t* const best_uv_base = SAFE_ALLOC(uv_w * 3, uv_h, fixed_t);
+  fixed_t* const target_uv_base = SAFE_ALLOC(uv_w * 3, uv_h, fixed_t);
+  fixed_t* const best_rgb_uv = SAFE_ALLOC(uv_w * 3, 1, fixed_t);
+  fixed_y_t* best_y = best_y_base;
+  fixed_y_t* target_y = target_y_base;
+  fixed_t* best_uv = best_uv_base;
+  fixed_t* target_uv = target_uv_base;
+  const uint64_t diff_y_threshold = (uint64_t)(3.0 * w * h);
+  int ok;
+  assert(w > 0);
+  assert(h > 0);
+
+  if (best_y_base == NULL || best_uv_base == NULL ||
+      target_y_base == NULL || target_uv_base == NULL ||
+      best_rgb_y == NULL || best_rgb_uv == NULL ||
+      tmp_buffer == NULL) {
+    ok = 0;
+    goto End;
+  }
+
+  // Import RGB samples to W/RGB representation.
+  for (j = 0; j < height; j += 2) {
+    const int is_last_row = (j == height - 1);
+    fixed_y_t* const src1 = tmp_buffer + 0 * w;
+    fixed_y_t* const src2 = tmp_buffer + 3 * w;
+
+    // prepare two rows of input
+    ImportOneRow(r_ptr, g_ptr, b_ptr, rgb_step, rgb_bit_depth, width,
+                 src1);
+    if (!is_last_row) {
+      ImportOneRow(r_ptr + rgb_stride, g_ptr + rgb_stride, b_ptr + rgb_stride,
+                   rgb_step, rgb_bit_depth, width, src2);
+    } else {
+      memcpy(src2, src1, 3 * w * sizeof(*src2));
+    }
+    StoreGray(src1, best_y + 0, w);
+    StoreGray(src2, best_y + w, w);
+
+    UpdateW(src1, target_y, w, rgb_bit_depth, transfer_type);
+    UpdateW(src2, target_y + w, w, rgb_bit_depth, transfer_type);
+    UpdateChroma(src1, src2, target_uv, uv_w, rgb_bit_depth, transfer_type);
+    memcpy(best_uv, target_uv, 3 * uv_w * sizeof(*best_uv));
+    best_y += 2 * w;
+    best_uv += 3 * uv_w;
+    target_y += 2 * w;
+    target_uv += 3 * uv_w;
+    r_ptr += 2 * rgb_stride;
+    g_ptr += 2 * rgb_stride;
+    b_ptr += 2 * rgb_stride;
+  }
+
+  // Iterate and resolve clipping conflicts.
+  for (iter = 0; iter < kNumIterations; ++iter) {
+    const fixed_t* cur_uv = best_uv_base;
+    const fixed_t* prev_uv = best_uv_base;
+    uint64_t diff_y_sum = 0;
+
+    best_y = best_y_base;
+    best_uv = best_uv_base;
+    target_y = target_y_base;
+    target_uv = target_uv_base;
+    j = 0;
+    do {
+      fixed_y_t* const src1 = tmp_buffer + 0 * w;
+      fixed_y_t* const src2 = tmp_buffer + 3 * w;
+      {
+        const fixed_t* const next_uv = cur_uv + ((j < h - 2) ? 3 * uv_w : 0);
+        InterpolateTwoRows(best_y, prev_uv, cur_uv, next_uv, w,
+                           src1, src2, rgb_bit_depth);
+        prev_uv = cur_uv;
+        cur_uv = next_uv;
+      }
+
+      UpdateW(src1, best_rgb_y + 0 * w, w, rgb_bit_depth, transfer_type);
+      UpdateW(src2, best_rgb_y + 1 * w, w, rgb_bit_depth, transfer_type);
+      UpdateChroma(src1, src2, best_rgb_uv, uv_w, rgb_bit_depth, transfer_type);
+
+      // update two rows of Y and one row of RGB
+      diff_y_sum +=
+          SharpYuvUpdateY(target_y, best_rgb_y, best_y, 2 * w, y_bit_depth);
+      SharpYuvUpdateRGB(target_uv, best_rgb_uv, best_uv, 3 * uv_w);
+
+      best_y += 2 * w;
+      best_uv += 3 * uv_w;
+      target_y += 2 * w;
+      target_uv += 3 * uv_w;
+      j += 2;
+    } while (j < h);
+    // test exit condition
+    if (iter > 0) {
+      if (diff_y_sum < diff_y_threshold) break;
+      if (diff_y_sum > prev_diff_y_sum) break;
+    }
+    prev_diff_y_sum = diff_y_sum;
+  }
+
+  // final reconstruction
+  ok = ConvertWRGBToYUV(best_y_base, best_uv_base, y_ptr, y_stride, u_ptr,
+                        u_stride, v_ptr, v_stride, rgb_bit_depth, yuv_bit_depth,
+                        width, height, yuv_matrix);
+
+ End:
+  free(best_y_base);
+  free(best_uv_base);
+  free(target_y_base);
+  free(target_uv_base);
+  free(best_rgb_y);
+  free(best_rgb_uv);
+  free(tmp_buffer);
+  return ok;
+}
+
+#undef SAFE_ALLOC
+
+#if defined(WEBP_USE_THREAD) && !defined(_WIN32)
+#include <pthread.h>  // NOLINT
+
+#define LOCK_ACCESS \
+    static pthread_mutex_t sharpyuv_lock = PTHREAD_MUTEX_INITIALIZER; \
+    if (pthread_mutex_lock(&sharpyuv_lock)) return
+#define UNLOCK_ACCESS_AND_RETURN                  \
+    do {                                          \
+      (void)pthread_mutex_unlock(&sharpyuv_lock); \
+      return;                                     \
+    } while (0)
+#else  // !(defined(WEBP_USE_THREAD) && !defined(_WIN32))
+#define LOCK_ACCESS do {} while (0)
+#define UNLOCK_ACCESS_AND_RETURN return
+#endif  // defined(WEBP_USE_THREAD) && !defined(_WIN32)
+
+// Hidden exported init function.
+// By default SharpYuvConvert calls it with SharpYuvGetCPUInfo. If needed,
+// users can declare it as extern and call it with an alternate VP8CPUInfo
+// function.
+extern VP8CPUInfo SharpYuvGetCPUInfo;
+SHARPYUV_EXTERN void SharpYuvInit(VP8CPUInfo cpu_info_func);
+void SharpYuvInit(VP8CPUInfo cpu_info_func) {
+  static volatile VP8CPUInfo sharpyuv_last_cpuinfo_used =
+      (VP8CPUInfo)&sharpyuv_last_cpuinfo_used;
+  LOCK_ACCESS;
+  // Only update SharpYuvGetCPUInfo when called from external code to avoid a
+  // race on reading the value in SharpYuvConvert().
+  if (cpu_info_func != (VP8CPUInfo)&SharpYuvGetCPUInfo) {
+    SharpYuvGetCPUInfo = cpu_info_func;
+  }
+  if (sharpyuv_last_cpuinfo_used == SharpYuvGetCPUInfo) {
+    UNLOCK_ACCESS_AND_RETURN;
+  }
+
+  SharpYuvInitDsp();
+  SharpYuvInitGammaTables();
+
+  sharpyuv_last_cpuinfo_used = SharpYuvGetCPUInfo;
+  UNLOCK_ACCESS_AND_RETURN;
+}
+
+int SharpYuvConvert(const void* r_ptr, const void* g_ptr, const void* b_ptr,
+                    int rgb_step, int rgb_stride, int rgb_bit_depth,
+                    void* y_ptr, int y_stride, void* u_ptr, int u_stride,
+                    void* v_ptr, int v_stride, int yuv_bit_depth, int width,
+                    int height, const SharpYuvConversionMatrix* yuv_matrix) {
+  SharpYuvOptions options;
+  options.yuv_matrix = yuv_matrix;
+  options.transfer_type = kSharpYuvTransferFunctionSrgb;
+  return SharpYuvConvertWithOptions(
+      r_ptr, g_ptr, b_ptr, rgb_step, rgb_stride, rgb_bit_depth, y_ptr, y_stride,
+      u_ptr, u_stride, v_ptr, v_stride, yuv_bit_depth, width, height, &options);
+}
+
+int SharpYuvOptionsInitInternal(const SharpYuvConversionMatrix* yuv_matrix,
+                                SharpYuvOptions* options, int version) {
+  const int major = (version >> 24);
+  const int minor = (version >> 16) & 0xff;
+  if (options == NULL || yuv_matrix == NULL ||
+      (major == SHARPYUV_VERSION_MAJOR && major == 0 &&
+       minor != SHARPYUV_VERSION_MINOR) ||
+      (major != SHARPYUV_VERSION_MAJOR)) {
+    return 0;
+  }
+  options->yuv_matrix = yuv_matrix;
+  options->transfer_type = kSharpYuvTransferFunctionSrgb;
+  return 1;
+}
+
+int SharpYuvConvertWithOptions(const void* r_ptr, const void* g_ptr,
+                               const void* b_ptr, int rgb_step, int rgb_stride,
+                               int rgb_bit_depth, void* y_ptr, int y_stride,
+                               void* u_ptr, int u_stride, void* v_ptr,
+                               int v_stride, int yuv_bit_depth, int width,
+                               int height, const SharpYuvOptions* options) {
+  const SharpYuvConversionMatrix* yuv_matrix = options->yuv_matrix;
+  SharpYuvTransferFunctionType transfer_type = options->transfer_type;
+  SharpYuvConversionMatrix scaled_matrix;
+  const int rgb_max = (1 << rgb_bit_depth) - 1;
+  const int rgb_round = 1 << (rgb_bit_depth - 1);
+  const int yuv_max = (1 << yuv_bit_depth) - 1;
+  const int sfix = GetPrecisionShift(rgb_bit_depth);
+
+  if (width < 1 || height < 1 || width == INT_MAX || height == INT_MAX ||
+      r_ptr == NULL || g_ptr == NULL || b_ptr == NULL || y_ptr == NULL ||
+      u_ptr == NULL || v_ptr == NULL) {
+    return 0;
+  }
+  if (rgb_bit_depth != 8 && rgb_bit_depth != 10 && rgb_bit_depth != 12 &&
+      rgb_bit_depth != 16) {
+    return 0;
+  }
+  if (yuv_bit_depth != 8 && yuv_bit_depth != 10 && yuv_bit_depth != 12) {
+    return 0;
+  }
+  if (rgb_bit_depth > 8 && (rgb_step % 2 != 0 || rgb_stride % 2 != 0)) {
+    // Step/stride should be even for uint16_t buffers.
+    return 0;
+  }
+  if (yuv_bit_depth > 8 &&
+      (y_stride % 2 != 0 || u_stride % 2 != 0 || v_stride % 2 != 0)) {
+    // Stride should be even for uint16_t buffers.
+    return 0;
+  }
+  // The address of the function pointer is used to avoid a read race.
+  SharpYuvInit((VP8CPUInfo)&SharpYuvGetCPUInfo);
+
+  // Add scaling factor to go from rgb_bit_depth to yuv_bit_depth, to the
+  // rgb->yuv conversion matrix.
+  if (rgb_bit_depth == yuv_bit_depth) {
+    memcpy(&scaled_matrix, yuv_matrix, sizeof(scaled_matrix));
+  } else {
+    int i;
+    for (i = 0; i < 3; ++i) {
+      scaled_matrix.rgb_to_y[i] =
+          (yuv_matrix->rgb_to_y[i] * yuv_max + rgb_round) / rgb_max;
+      scaled_matrix.rgb_to_u[i] =
+          (yuv_matrix->rgb_to_u[i] * yuv_max + rgb_round) / rgb_max;
+      scaled_matrix.rgb_to_v[i] =
+          (yuv_matrix->rgb_to_v[i] * yuv_max + rgb_round) / rgb_max;
+    }
+  }
+  // Also incorporate precision change scaling.
+  scaled_matrix.rgb_to_y[3] = Shift(yuv_matrix->rgb_to_y[3], sfix);
+  scaled_matrix.rgb_to_u[3] = Shift(yuv_matrix->rgb_to_u[3], sfix);
+  scaled_matrix.rgb_to_v[3] = Shift(yuv_matrix->rgb_to_v[3], sfix);
+
+  return DoSharpArgbToYuv(
+      (const uint8_t*)r_ptr, (const uint8_t*)g_ptr, (const uint8_t*)b_ptr,
+      rgb_step, rgb_stride, rgb_bit_depth, (uint8_t*)y_ptr, y_stride,
+      (uint8_t*)u_ptr, u_stride, (uint8_t*)v_ptr, v_stride, yuv_bit_depth,
+      width, height, &scaled_matrix, transfer_type);
+}
+
+//------------------------------------------------------------------------------

sharpyuv/sharpyuv.h

@@ -0,0 +1,181 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Sharp RGB to YUV conversion.
+
+#ifndef WEBP_SHARPYUV_SHARPYUV_H_
+#define WEBP_SHARPYUV_SHARPYUV_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef SHARPYUV_EXTERN
+#ifdef WEBP_EXTERN
+#define SHARPYUV_EXTERN WEBP_EXTERN
+#else
+// This explicitly marks library functions and allows for changing the
+// signature for e.g., Windows DLL builds.
+#if defined(_WIN32) && defined(WEBP_DLL)
+#define SHARPYUV_EXTERN __declspec(dllexport)
+#elif defined(__GNUC__) && __GNUC__ >= 4
+#define SHARPYUV_EXTERN extern __attribute__((visibility("default")))
+#else
+#define SHARPYUV_EXTERN extern
+#endif /* defined(_WIN32) && defined(WEBP_DLL) */
+#endif /* WEBP_EXTERN */
+#endif /* SHARPYUV_EXTERN */
+
+#ifndef SHARPYUV_INLINE
+#ifdef WEBP_INLINE
+#define SHARPYUV_INLINE WEBP_INLINE
+#else
+#ifndef _MSC_VER
+#if defined(__cplusplus) || !defined(__STRICT_ANSI__) || \
+    (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)
+#define SHARPYUV_INLINE inline
+#else
+#define SHARPYUV_INLINE
+#endif
+#else
+#define SHARPYUV_INLINE __forceinline
+#endif /* _MSC_VER */
+#endif /* WEBP_INLINE */
+#endif /* SHARPYUV_INLINE */
+
+// SharpYUV API version following the convention from semver.org
+#define SHARPYUV_VERSION_MAJOR 0
+#define SHARPYUV_VERSION_MINOR 4
+#define SHARPYUV_VERSION_PATCH 0
+// Version as a uint32_t. The major number is the high 8 bits.
+// The minor number is the middle 8 bits. The patch number is the low 16 bits.
+#define SHARPYUV_MAKE_VERSION(MAJOR, MINOR, PATCH) \
+  (((MAJOR) << 24) | ((MINOR) << 16) | (PATCH))
+#define SHARPYUV_VERSION                                                \
+  SHARPYUV_MAKE_VERSION(SHARPYUV_VERSION_MAJOR, SHARPYUV_VERSION_MINOR, \
+                        SHARPYUV_VERSION_PATCH)
+
+// Returns the library's version number, packed in hexadecimal. See
+// SHARPYUV_VERSION.
+SHARPYUV_EXTERN int SharpYuvGetVersion(void);
+
+// RGB to YUV conversion matrix, in 16 bit fixed point.
+// y_ = rgb_to_y[0] * r + rgb_to_y[1] * g + rgb_to_y[2] * b + rgb_to_y[3]
+// u_ = rgb_to_u[0] * r + rgb_to_u[1] * g + rgb_to_u[2] * b + rgb_to_u[3]
+// v_ = rgb_to_v[0] * r + rgb_to_v[1] * g + rgb_to_v[2] * b + rgb_to_v[3]
+// Then the values are divided by 1<<16 and rounded.
+// y = (y_ + (1 << 15)) >> 16
+// u = (u_ + (1 << 15)) >> 16
+// v = (v_ + (1 << 15)) >> 16
+//
+// Typically, the offset values rgb_to_y[3], rgb_to_u[3] and rgb_to_v[3] depend
+// on the input's bit depth, e.g., rgb_to_u[3] = 1 << (rgb_bit_depth - 1 + 16).
+// See also sharpyuv_csp.h to get a predefined matrix or generate a matrix.
+typedef struct {
+  int rgb_to_y[4];
+  int rgb_to_u[4];
+  int rgb_to_v[4];
+} SharpYuvConversionMatrix;
+
+typedef struct SharpYuvOptions SharpYuvOptions;
+
+// Enums for transfer functions, as defined in H.273,
+// https://www.itu.int/rec/T-REC-H.273-202107-I/en
+typedef enum SharpYuvTransferFunctionType {
+  // 0 is reserved
+  kSharpYuvTransferFunctionBt709 = 1,
+  // 2 is unspecified
+  // 3 is reserved
+  kSharpYuvTransferFunctionBt470M = 4,
+  kSharpYuvTransferFunctionBt470Bg = 5,
+  kSharpYuvTransferFunctionBt601 = 6,
+  kSharpYuvTransferFunctionSmpte240 = 7,
+  kSharpYuvTransferFunctionLinear = 8,
+  kSharpYuvTransferFunctionLog100 = 9,
+  kSharpYuvTransferFunctionLog100_Sqrt10 = 10,
+  kSharpYuvTransferFunctionIec61966 = 11,
+  kSharpYuvTransferFunctionBt1361 = 12,
+  kSharpYuvTransferFunctionSrgb = 13,
+  kSharpYuvTransferFunctionBt2020_10Bit = 14,
+  kSharpYuvTransferFunctionBt2020_12Bit = 15,
+  kSharpYuvTransferFunctionSmpte2084 = 16,  // PQ
+  kSharpYuvTransferFunctionSmpte428 = 17,
+  kSharpYuvTransferFunctionHlg = 18,
+  kSharpYuvTransferFunctionNum
+} SharpYuvTransferFunctionType;
+
+// Converts RGB to YUV420 using a downsampling algorithm that minimizes
+// artefacts caused by chroma subsampling.
+// This is slower than standard downsampling (averaging of 4 UV values).
+// Assumes that the image will be upsampled using a bilinear filter. If nearest
+// neighbor is used instead, the upsampled image might look worse than with
+// standard downsampling.
+// r_ptr, g_ptr, b_ptr: pointers to the source r, g and b channels. Should point
+//     to uint8_t buffers if rgb_bit_depth is 8, or uint16_t buffers otherwise.
+// rgb_step: distance in bytes between two horizontally adjacent pixels on the
+//     r, g and b channels. If rgb_bit_depth is > 8, it should be a
+//     multiple of 2.
+// rgb_stride: distance in bytes between two vertically adjacent pixels on the
+//     r, g, and b channels. If rgb_bit_depth is > 8, it should be a
+//     multiple of 2.
+// rgb_bit_depth: number of bits for each r/g/b value. One of: 8, 10, 12, 16.
+//     Note: 16 bit input is truncated to 14 bits before conversion to yuv.
+// yuv_bit_depth: number of bits for each y/u/v value. One of: 8, 10, 12.
+// y_ptr, u_ptr, v_ptr: pointers to the destination y, u and v channels.  Should
+//     point to uint8_t buffers if yuv_bit_depth is 8, or uint16_t buffers
+//     otherwise.
+// y_stride, u_stride, v_stride: distance in bytes between two vertically
+//     adjacent pixels on the y, u and v channels. If yuv_bit_depth > 8, they
+//     should be multiples of 2.
+// width, height: width and height of the image in pixels
+// yuv_matrix: RGB to YUV conversion matrix. The matrix values typically
+//     depend on the input's rgb_bit_depth.
+// This function calls SharpYuvConvertWithOptions with a default transfer
+// function of kSharpYuvTransferFunctionSrgb.
+SHARPYUV_EXTERN int SharpYuvConvert(const void* r_ptr, const void* g_ptr,
+                                    const void* b_ptr, int rgb_step,
+                                    int rgb_stride, int rgb_bit_depth,
+                                    void* y_ptr, int y_stride, void* u_ptr,
+                                    int u_stride, void* v_ptr, int v_stride,
+                                    int yuv_bit_depth, int width, int height,
+                                    const SharpYuvConversionMatrix* yuv_matrix);
+
+struct SharpYuvOptions {
+  // This matrix cannot be NULL and can be initialized by
+  // SharpYuvComputeConversionMatrix.
+  const SharpYuvConversionMatrix* yuv_matrix;
+  SharpYuvTransferFunctionType transfer_type;
+};
+
+// Internal, version-checked, entry point
+SHARPYUV_EXTERN int SharpYuvOptionsInitInternal(const SharpYuvConversionMatrix*,
+                                                SharpYuvOptions*, int);
+
+// Should always be called, to initialize a fresh SharpYuvOptions
+// structure before modification. SharpYuvOptionsInit() must have succeeded
+// before using the 'options' object.
+static SHARPYUV_INLINE int SharpYuvOptionsInit(
+    const SharpYuvConversionMatrix* yuv_matrix, SharpYuvOptions* options) {
+  return SharpYuvOptionsInitInternal(yuv_matrix, options, SHARPYUV_VERSION);
+}
+
+SHARPYUV_EXTERN int SharpYuvConvertWithOptions(
+    const void* r_ptr, const void* g_ptr, const void* b_ptr, int rgb_step,
+    int rgb_stride, int rgb_bit_depth, void* y_ptr, int y_stride, void* u_ptr,
+    int u_stride, void* v_ptr, int v_stride, int yuv_bit_depth, int width,
+    int height, const SharpYuvOptions* options);
+
+// TODO(b/194336375): Add YUV444 to YUV420 conversion. Maybe also add 422
+// support (it's rarely used in practice, especially for images).
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // WEBP_SHARPYUV_SHARPYUV_H_

sharpyuv/sharpyuv_cpu.c

@@ -0,0 +1,14 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+#include "sharpyuv/sharpyuv_cpu.h"
+
+// Include src/dsp/cpu.c to create SharpYuvGetCPUInfo from VP8GetCPUInfo. The
+// function pointer is renamed in sharpyuv_cpu.h.
+#include "src/dsp/cpu.c"

sharpyuv/sharpyuv_cpu.h

@@ -0,0 +1,22 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+#ifndef WEBP_SHARPYUV_SHARPYUV_CPU_H_
+#define WEBP_SHARPYUV_SHARPYUV_CPU_H_
+
+#include "sharpyuv/sharpyuv.h"
+
+// Avoid exporting SharpYuvGetCPUInfo in shared object / DLL builds.
+// SharpYuvInit() replaces the use of the function pointer.
+#undef WEBP_EXTERN
+#define WEBP_EXTERN extern
+#define VP8GetCPUInfo SharpYuvGetCPUInfo
+#include "src/dsp/cpu.h"
+
+#endif  // WEBP_SHARPYUV_SHARPYUV_CPU_H_

sharpyuv/sharpyuv_csp.c

@@ -0,0 +1,110 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Colorspace utilities.
+
+#include "sharpyuv/sharpyuv_csp.h"
+
+#include <assert.h>
+#include <math.h>
+#include <stddef.h>
+
+static int ToFixed16(float f) { return (int)floor(f * (1 << 16) + 0.5f); }
+
+void SharpYuvComputeConversionMatrix(const SharpYuvColorSpace* yuv_color_space,
+                                     SharpYuvConversionMatrix* matrix) {
+  const float kr = yuv_color_space->kr;
+  const float kb = yuv_color_space->kb;
+  const float kg = 1.0f - kr - kb;
+  const float cr = 0.5f / (1.0f - kb);
+  const float cb = 0.5f / (1.0f - kr);
+
+  const int shift = yuv_color_space->bit_depth - 8;
+
+  const float denom = (float)((1 << yuv_color_space->bit_depth) - 1);
+  float scale_y = 1.0f;
+  float add_y = 0.0f;
+  float scale_u = cr;
+  float scale_v = cb;
+  float add_uv = (float)(128 << shift);
+  assert(yuv_color_space->bit_depth >= 8);
+
+  if (yuv_color_space->range == kSharpYuvRangeLimited) {
+    scale_y *= (219 << shift) / denom;
+    scale_u *= (224 << shift) / denom;
+    scale_v *= (224 << shift) / denom;
+    add_y = (float)(16 << shift);
+  }
+
+  matrix->rgb_to_y[0] = ToFixed16(kr * scale_y);
+  matrix->rgb_to_y[1] = ToFixed16(kg * scale_y);
+  matrix->rgb_to_y[2] = ToFixed16(kb * scale_y);
+  matrix->rgb_to_y[3] = ToFixed16(add_y);
+
+  matrix->rgb_to_u[0] = ToFixed16(-kr * scale_u);
+  matrix->rgb_to_u[1] = ToFixed16(-kg * scale_u);
+  matrix->rgb_to_u[2] = ToFixed16((1 - kb) * scale_u);
+  matrix->rgb_to_u[3] = ToFixed16(add_uv);
+
+  matrix->rgb_to_v[0] = ToFixed16((1 - kr) * scale_v);
+  matrix->rgb_to_v[1] = ToFixed16(-kg * scale_v);
+  matrix->rgb_to_v[2] = ToFixed16(-kb * scale_v);
+  matrix->rgb_to_v[3] = ToFixed16(add_uv);
+}
+
+// Matrices are in YUV_FIX fixed point precision.
+// WebP's matrix, similar but not identical to kRec601LimitedMatrix
+static const SharpYuvConversionMatrix kWebpMatrix = {
+  {16839, 33059, 6420, 16 << 16},
+  {-9719, -19081, 28800, 128 << 16},
+  {28800, -24116, -4684, 128 << 16},
+};
+// Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeLimited
+static const SharpYuvConversionMatrix kRec601LimitedMatrix = {
+  {16829, 33039, 6416, 16 << 16},
+  {-9714, -19071, 28784, 128 << 16},
+  {28784, -24103, -4681, 128 << 16},
+};
+// Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeFull
+static const SharpYuvConversionMatrix kRec601FullMatrix = {
+  {19595, 38470, 7471, 0},
+  {-11058, -21710, 32768, 128 << 16},
+  {32768, -27439, -5329, 128 << 16},
+};
+// Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeLimited
+static const SharpYuvConversionMatrix kRec709LimitedMatrix = {
+  {11966, 40254, 4064, 16 << 16},
+  {-6596, -22189, 28784, 128 << 16},
+  {28784, -26145, -2639, 128 << 16},
+};
+// Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeFull
+static const SharpYuvConversionMatrix kRec709FullMatrix = {
+  {13933, 46871, 4732, 0},
+  {-7509, -25259, 32768, 128 << 16},
+  {32768, -29763, -3005, 128 << 16},
+};
+
+const SharpYuvConversionMatrix* SharpYuvGetConversionMatrix(
+    SharpYuvMatrixType matrix_type) {
+  switch (matrix_type) {
+    case kSharpYuvMatrixWebp:
+      return &kWebpMatrix;
+    case kSharpYuvMatrixRec601Limited:
+      return &kRec601LimitedMatrix;
+    case kSharpYuvMatrixRec601Full:
+      return &kRec601FullMatrix;
+    case kSharpYuvMatrixRec709Limited:
+      return &kRec709LimitedMatrix;
+    case kSharpYuvMatrixRec709Full:
+      return &kRec709FullMatrix;
+    case kSharpYuvMatrixNum:
+      return NULL;
+  }
+  return NULL;
+}

sharpyuv/sharpyuv_csp.h

@@ -0,0 +1,65 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Colorspace utilities.
+
+#ifndef WEBP_SHARPYUV_SHARPYUV_CSP_H_
+#define WEBP_SHARPYUV_SHARPYUV_CSP_H_
+
+#include "sharpyuv/sharpyuv.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Range of YUV values.
+typedef enum {
+  kSharpYuvRangeFull,     // YUV values between [0;255] (for 8 bit)
+  kSharpYuvRangeLimited   // Y in [16;235], YUV in [16;240] (for 8 bit)
+} SharpYuvRange;
+
+// Constants that define a YUV color space.
+typedef struct {
+  // Kr and Kb are defined such that:
+  // Y = Kr * r + Kg * g + Kb * b where Kg = 1 - Kr - Kb.
+  float kr;
+  float kb;
+  int bit_depth;  // 8, 10 or 12
+  SharpYuvRange range;
+} SharpYuvColorSpace;
+
+// Fills in 'matrix' for the given YUVColorSpace.
+SHARPYUV_EXTERN void SharpYuvComputeConversionMatrix(
+    const SharpYuvColorSpace* yuv_color_space,
+    SharpYuvConversionMatrix* matrix);
+
+// Enums for precomputed conversion matrices.
+typedef enum {
+  // WebP's matrix, similar but not identical to kSharpYuvMatrixRec601Limited
+  kSharpYuvMatrixWebp = 0,
+  // Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeLimited
+  kSharpYuvMatrixRec601Limited,
+  // Kr=0.2990f Kb=0.1140f bit_depth=8 range=kSharpYuvRangeFull
+  kSharpYuvMatrixRec601Full,
+  // Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeLimited
+  kSharpYuvMatrixRec709Limited,
+  // Kr=0.2126f Kb=0.0722f bit_depth=8 range=kSharpYuvRangeFull
+  kSharpYuvMatrixRec709Full,
+  kSharpYuvMatrixNum
+} SharpYuvMatrixType;
+
+// Returns a pointer to a matrix for one of the predefined colorspaces.
+SHARPYUV_EXTERN const SharpYuvConversionMatrix* SharpYuvGetConversionMatrix(
+    SharpYuvMatrixType matrix_type);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // WEBP_SHARPYUV_SHARPYUV_CSP_H_

sharpyuv/sharpyuv_dsp.c

@@ -0,0 +1,104 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Speed-critical functions for Sharp YUV.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "sharpyuv/sharpyuv_dsp.h"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include "sharpyuv/sharpyuv_cpu.h"
+#include "src/webp/types.h"
+
+//-----------------------------------------------------------------------------
+
+#if !WEBP_NEON_OMIT_C_CODE
+static uint16_t clip(int v, int max) {
+  return (v < 0) ? 0 : (v > max) ? max : (uint16_t)v;
+}
+
+static uint64_t SharpYuvUpdateY_C(const uint16_t* ref, const uint16_t* src,
+                                  uint16_t* dst, int len, int bit_depth) {
+  uint64_t diff = 0;
+  int i;
+  const int max_y = (1 << bit_depth) - 1;
+  for (i = 0; i < len; ++i) {
+    const int diff_y = ref[i] - src[i];
+    const int new_y = (int)dst[i] + diff_y;
+    dst[i] = clip(new_y, max_y);
+    diff += (uint64_t)abs(diff_y);
+  }
+  return diff;
+}
+
+static void SharpYuvUpdateRGB_C(const int16_t* ref, const int16_t* src,
+                                int16_t* dst, int len) {
+  int i;
+  for (i = 0; i < len; ++i) {
+    const int diff_uv = ref[i] - src[i];
+    dst[i] += diff_uv;
+  }
+}
+
+static void SharpYuvFilterRow_C(const int16_t* A, const int16_t* B, int len,
+                                const uint16_t* best_y, uint16_t* out,
+                                int bit_depth) {
+  int i;
+  const int max_y = (1 << bit_depth) - 1;
+  for (i = 0; i < len; ++i, ++A, ++B) {
+    const int v0 = (A[0] * 9 + A[1] * 3 + B[0] * 3 + B[1] + 8) >> 4;
+    const int v1 = (A[1] * 9 + A[0] * 3 + B[1] * 3 + B[0] + 8) >> 4;
+    out[2 * i + 0] = clip(best_y[2 * i + 0] + v0, max_y);
+    out[2 * i + 1] = clip(best_y[2 * i + 1] + v1, max_y);
+  }
+}
+#endif  // !WEBP_NEON_OMIT_C_CODE
+
+//-----------------------------------------------------------------------------
+
+uint64_t (*SharpYuvUpdateY)(const uint16_t* src, const uint16_t* ref,
+                            uint16_t* dst, int len, int bit_depth);
+void (*SharpYuvUpdateRGB)(const int16_t* src, const int16_t* ref, int16_t* dst,
+                          int len);
+void (*SharpYuvFilterRow)(const int16_t* A, const int16_t* B, int len,
+                          const uint16_t* best_y, uint16_t* out, int bit_depth);
+
+extern VP8CPUInfo SharpYuvGetCPUInfo;
+extern void InitSharpYuvSSE2(void);
+extern void InitSharpYuvNEON(void);
+
+void SharpYuvInitDsp(void) {
+#if !WEBP_NEON_OMIT_C_CODE
+  SharpYuvUpdateY = SharpYuvUpdateY_C;
+  SharpYuvUpdateRGB = SharpYuvUpdateRGB_C;
+  SharpYuvFilterRow = SharpYuvFilterRow_C;
+#endif
+
+  if (SharpYuvGetCPUInfo != NULL) {
+#if defined(WEBP_HAVE_SSE2)
+    if (SharpYuvGetCPUInfo(kSSE2)) {
+      InitSharpYuvSSE2();
+    }
+#endif  // WEBP_HAVE_SSE2
+  }
+
+#if defined(WEBP_HAVE_NEON)
+  if (WEBP_NEON_OMIT_C_CODE ||
+      (SharpYuvGetCPUInfo != NULL && SharpYuvGetCPUInfo(kNEON))) {
+    InitSharpYuvNEON();
+  }
+#endif  // WEBP_HAVE_NEON
+
+  assert(SharpYuvUpdateY != NULL);
+  assert(SharpYuvUpdateRGB != NULL);
+  assert(SharpYuvFilterRow != NULL);
+}

sharpyuv/sharpyuv_dsp.h

@@ -0,0 +1,28 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Speed-critical functions for Sharp YUV.
+
+#ifndef WEBP_SHARPYUV_SHARPYUV_DSP_H_
+#define WEBP_SHARPYUV_SHARPYUV_DSP_H_
+
+#include "sharpyuv/sharpyuv_cpu.h"
+#include "src/webp/types.h"
+
+extern uint64_t (*SharpYuvUpdateY)(const uint16_t* src, const uint16_t* ref,
+                                   uint16_t* dst, int len, int bit_depth);
+extern void (*SharpYuvUpdateRGB)(const int16_t* src, const int16_t* ref,
+                                 int16_t* dst, int len);
+extern void (*SharpYuvFilterRow)(const int16_t* A, const int16_t* B, int len,
+                                 const uint16_t* best_y, uint16_t* out,
+                                 int bit_depth);
+
+void SharpYuvInitDsp(void);
+
+#endif  // WEBP_SHARPYUV_SHARPYUV_DSP_H_

sharpyuv/sharpyuv_gamma.c

@@ -0,0 +1,419 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Gamma correction utilities.
+
+#include "sharpyuv/sharpyuv_gamma.h"
+
+#include <assert.h>
+#include <float.h>
+#include <math.h>
+
+#include "src/webp/types.h"
+
+// Gamma correction compensates loss of resolution during chroma subsampling.
+// Size of pre-computed table for converting from gamma to linear.
+#define GAMMA_TO_LINEAR_TAB_BITS 10
+#define GAMMA_TO_LINEAR_TAB_SIZE (1 << GAMMA_TO_LINEAR_TAB_BITS)
+static uint32_t kGammaToLinearTabS[GAMMA_TO_LINEAR_TAB_SIZE + 2];
+#define LINEAR_TO_GAMMA_TAB_BITS 9
+#define LINEAR_TO_GAMMA_TAB_SIZE (1 << LINEAR_TO_GAMMA_TAB_BITS)
+static uint32_t kLinearToGammaTabS[LINEAR_TO_GAMMA_TAB_SIZE + 2];
+
+static const double kGammaF = 1. / 0.45;
+#define GAMMA_TO_LINEAR_BITS 16
+
+static volatile int kGammaTablesSOk = 0;
+void SharpYuvInitGammaTables(void) {
+  assert(GAMMA_TO_LINEAR_BITS <= 16);
+  if (!kGammaTablesSOk) {
+    int v;
+    const double a = 0.09929682680944;
+    const double thresh = 0.018053968510807;
+    const double final_scale = 1 << GAMMA_TO_LINEAR_BITS;
+    // Precompute gamma to linear table.
+    {
+      const double norm = 1. / GAMMA_TO_LINEAR_TAB_SIZE;
+      const double a_rec = 1. / (1. + a);
+      for (v = 0; v <= GAMMA_TO_LINEAR_TAB_SIZE; ++v) {
+        const double g = norm * v;
+        double value;
+        if (g <= thresh * 4.5) {
+          value = g / 4.5;
+        } else {
+          value = pow(a_rec * (g + a), kGammaF);
+        }
+        kGammaToLinearTabS[v] = (uint32_t)(value * final_scale + .5);
+      }
+      // to prevent small rounding errors to cause read-overflow:
+      kGammaToLinearTabS[GAMMA_TO_LINEAR_TAB_SIZE + 1] =
+          kGammaToLinearTabS[GAMMA_TO_LINEAR_TAB_SIZE];
+    }
+    // Precompute linear to gamma table.
+    {
+      const double scale = 1. / LINEAR_TO_GAMMA_TAB_SIZE;
+      for (v = 0; v <= LINEAR_TO_GAMMA_TAB_SIZE; ++v) {
+        const double g = scale * v;
+        double value;
+        if (g <= thresh) {
+          value = 4.5 * g;
+        } else {
+          value = (1. + a) * pow(g, 1. / kGammaF) - a;
+        }
+        kLinearToGammaTabS[v] =
+            (uint32_t)(final_scale * value + 0.5);
+      }
+      // to prevent small rounding errors to cause read-overflow:
+      kLinearToGammaTabS[LINEAR_TO_GAMMA_TAB_SIZE + 1] =
+          kLinearToGammaTabS[LINEAR_TO_GAMMA_TAB_SIZE];
+    }
+    kGammaTablesSOk = 1;
+  }
+}
+
+static WEBP_INLINE int Shift(int v, int shift) {
+  return (shift >= 0) ? (v << shift) : (v >> -shift);
+}
+
+static WEBP_INLINE uint32_t FixedPointInterpolation(int v, uint32_t* tab,
+                                                    int tab_pos_shift_right,
+                                                    int tab_value_shift) {
+  const uint32_t tab_pos = Shift(v, -tab_pos_shift_right);
+  // fractional part, in 'tab_pos_shift' fixed-point precision
+  const uint32_t x = v - (tab_pos << tab_pos_shift_right);  // fractional part
+  // v0 / v1 are in kGammaToLinearBits fixed-point precision (range [0..1])
+  const uint32_t v0 = Shift(tab[tab_pos + 0], tab_value_shift);
+  const uint32_t v1 = Shift(tab[tab_pos + 1], tab_value_shift);
+  // Final interpolation.
+  const uint32_t v2 = (v1 - v0) * x;  // note: v1 >= v0.
+  const int half =
+      (tab_pos_shift_right > 0) ? 1 << (tab_pos_shift_right - 1) : 0;
+  const uint32_t result = v0 + ((v2 + half) >> tab_pos_shift_right);
+  return result;
+}
+
+static uint32_t ToLinearSrgb(uint16_t v, int bit_depth) {
+  const int shift = GAMMA_TO_LINEAR_TAB_BITS - bit_depth;
+  if (shift > 0) {
+    return kGammaToLinearTabS[v << shift];
+  }
+  return FixedPointInterpolation(v, kGammaToLinearTabS, -shift, 0);
+}
+
+static uint16_t FromLinearSrgb(uint32_t value, int bit_depth) {
+  return FixedPointInterpolation(
+      value, kLinearToGammaTabS,
+      (GAMMA_TO_LINEAR_BITS - LINEAR_TO_GAMMA_TAB_BITS),
+      bit_depth - GAMMA_TO_LINEAR_BITS);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+#define CLAMP(x, low, high) \
+  (((x) < (low)) ? (low) : (((high) < (x)) ? (high) : (x)))
+#define MIN(a, b) (((a) < (b)) ? (a) : (b))
+#define MAX(a, b) (((a) > (b)) ? (a) : (b))
+
+static WEBP_INLINE float Roundf(float x) {
+  if (x < 0)
+    return (float)ceil((double)(x - 0.5f));
+  else
+    return (float)floor((double)(x + 0.5f));
+}
+
+static WEBP_INLINE float Powf(float base, float exp) {
+  return (float)pow((double)base, (double)exp);
+}
+
+static WEBP_INLINE float Log10f(float x) { return (float)log10((double)x); }
+
+static float ToLinear709(float gamma) {
+  if (gamma < 0.f) {
+    return 0.f;
+  } else if (gamma < 4.5f * 0.018053968510807f) {
+    return gamma / 4.5f;
+  } else if (gamma < 1.f) {
+    return Powf((gamma + 0.09929682680944f) / 1.09929682680944f, 1.f / 0.45f);
+  }
+  return 1.f;
+}
+
+static float FromLinear709(float linear) {
+  if (linear < 0.f) {
+    return 0.f;
+  } else if (linear < 0.018053968510807f) {
+    return linear * 4.5f;
+  } else if (linear < 1.f) {
+    return 1.09929682680944f * Powf(linear, 0.45f) - 0.09929682680944f;
+  }
+  return 1.f;
+}
+
+static float ToLinear470M(float gamma) {
+  return Powf(CLAMP(gamma, 0.f, 1.f), 2.2f);
+}
+
+static float FromLinear470M(float linear) {
+  return Powf(CLAMP(linear, 0.f, 1.f), 1.f / 2.2f);
+}
+
+static float ToLinear470Bg(float gamma) {
+  return Powf(CLAMP(gamma, 0.f, 1.f), 2.8f);
+}
+
+static float FromLinear470Bg(float linear) {
+  return Powf(CLAMP(linear, 0.f, 1.f), 1.f / 2.8f);
+}
+
+static float ToLinearSmpte240(float gamma) {
+  if (gamma < 0.f) {
+    return 0.f;
+  } else if (gamma < 4.f * 0.022821585529445f) {
+    return gamma / 4.f;
+  } else if (gamma < 1.f) {
+    return Powf((gamma + 0.111572195921731f) / 1.111572195921731f, 1.f / 0.45f);
+  }
+  return 1.f;
+}
+
+static float FromLinearSmpte240(float linear) {
+  if (linear < 0.f) {
+    return 0.f;
+  } else if (linear < 0.022821585529445f) {
+    return linear * 4.f;
+  } else if (linear < 1.f) {
+    return 1.111572195921731f * Powf(linear, 0.45f) - 0.111572195921731f;
+  }
+  return 1.f;
+}
+
+static float ToLinearLog100(float gamma) {
+  // The function is non-bijective so choose the middle of [0, 0.01].
+  const float mid_interval = 0.01f / 2.f;
+  return (gamma <= 0.0f) ? mid_interval
+                          : Powf(10.0f, 2.f * (MIN(gamma, 1.f) - 1.0f));
+}
+
+static float FromLinearLog100(float linear) {
+  return (linear < 0.01f) ? 0.0f : 1.0f + Log10f(MIN(linear, 1.f)) / 2.0f;
+}
+
+static float ToLinearLog100Sqrt10(float gamma) {
+  // The function is non-bijective so choose the middle of [0, 0.00316227766f[.
+  const float mid_interval = 0.00316227766f / 2.f;
+  return (gamma <= 0.0f) ? mid_interval
+                          : Powf(10.0f, 2.5f * (MIN(gamma, 1.f) - 1.0f));
+}
+
+static float FromLinearLog100Sqrt10(float linear) {
+  return (linear < 0.00316227766f) ? 0.0f
+                                  : 1.0f + Log10f(MIN(linear, 1.f)) / 2.5f;
+}
+
+static float ToLinearIec61966(float gamma) {
+  if (gamma <= -4.5f * 0.018053968510807f) {
+    return Powf((-gamma + 0.09929682680944f) / -1.09929682680944f, 1.f / 0.45f);
+  } else if (gamma < 4.5f * 0.018053968510807f) {
+    return gamma / 4.5f;
+  }
+  return Powf((gamma + 0.09929682680944f) / 1.09929682680944f, 1.f / 0.45f);
+}
+
+static float FromLinearIec61966(float linear) {
+  if (linear <= -0.018053968510807f) {
+    return -1.09929682680944f * Powf(-linear, 0.45f) + 0.09929682680944f;
+  } else if (linear < 0.018053968510807f) {
+    return linear * 4.5f;
+  }
+  return 1.09929682680944f * Powf(linear, 0.45f) - 0.09929682680944f;
+}
+
+static float ToLinearBt1361(float gamma) {
+  if (gamma < -0.25f) {
+    return -0.25f;
+  } else if (gamma < 0.f) {
+    return Powf((gamma - 0.02482420670236f) / -0.27482420670236f, 1.f / 0.45f) /
+           -4.f;
+  } else if (gamma < 4.5f * 0.018053968510807f) {
+    return gamma / 4.5f;
+  } else if (gamma < 1.f) {
+    return Powf((gamma + 0.09929682680944f) / 1.09929682680944f, 1.f / 0.45f);
+  }
+  return 1.f;
+}
+
+static float FromLinearBt1361(float linear) {
+  if (linear < -0.25f) {
+    return -0.25f;
+  } else if (linear < 0.f) {
+    return -0.27482420670236f * Powf(-4.f * linear, 0.45f) + 0.02482420670236f;
+  } else if (linear < 0.018053968510807f) {
+    return linear * 4.5f;
+  } else if (linear < 1.f) {
+    return 1.09929682680944f * Powf(linear, 0.45f) - 0.09929682680944f;
+  }
+  return 1.f;
+}
+
+static float ToLinearPq(float gamma) {
+  if (gamma > 0.f) {
+    const float pow_gamma = Powf(gamma, 32.f / 2523.f);
+    const float num = MAX(pow_gamma - 107.f / 128.f, 0.0f);
+    const float den = MAX(2413.f / 128.f - 2392.f / 128.f * pow_gamma, FLT_MIN);
+    return Powf(num / den, 4096.f / 653.f);
+  }
+  return 0.f;
+}
+
+static float FromLinearPq(float linear) {
+  if (linear > 0.f) {
+    const float pow_linear = Powf(linear, 653.f / 4096.f);
+    const float num = 107.f / 128.f + 2413.f / 128.f * pow_linear;
+    const float den = 1.0f + 2392.f / 128.f * pow_linear;
+    return Powf(num / den, 2523.f / 32.f);
+  }
+  return 0.f;
+}
+
+static float ToLinearSmpte428(float gamma) {
+  return Powf(MAX(gamma, 0.f), 2.6f) / 0.91655527974030934f;
+}
+
+static float FromLinearSmpte428(float linear) {
+  return Powf(0.91655527974030934f * MAX(linear, 0.f), 1.f / 2.6f);
+}
+
+// Conversion in BT.2100 requires RGB info. Simplify to gamma correction here.
+static float ToLinearHlg(float gamma) {
+  if (gamma < 0.f) {
+    return 0.f;
+  } else if (gamma <= 0.5f) {
+    return Powf((gamma * gamma) * (1.f / 3.f), 1.2f);
+  }
+  return Powf((expf((gamma - 0.55991073f) / 0.17883277f) + 0.28466892f) / 12.0f,
+              1.2f);
+}
+
+static float FromLinearHlg(float linear) {
+  linear = Powf(linear, 1.f / 1.2f);
+  if (linear < 0.f) {
+    return 0.f;
+  } else if (linear <= (1.f / 12.f)) {
+    return sqrtf(3.f * linear);
+  }
+  return 0.17883277f * logf(12.f * linear - 0.28466892f) + 0.55991073f;
+}
+
+uint32_t SharpYuvGammaToLinear(uint16_t v, int bit_depth,
+                               SharpYuvTransferFunctionType transfer_type) {
+  float v_float, linear;
+  if (transfer_type == kSharpYuvTransferFunctionSrgb) {
+    return ToLinearSrgb(v, bit_depth);
+  }
+  v_float = (float)v / ((1 << bit_depth) - 1);
+  switch (transfer_type) {
+    case kSharpYuvTransferFunctionBt709:
+    case kSharpYuvTransferFunctionBt601:
+    case kSharpYuvTransferFunctionBt2020_10Bit:
+    case kSharpYuvTransferFunctionBt2020_12Bit:
+      linear = ToLinear709(v_float);
+      break;
+    case kSharpYuvTransferFunctionBt470M:
+      linear = ToLinear470M(v_float);
+      break;
+    case kSharpYuvTransferFunctionBt470Bg:
+      linear = ToLinear470Bg(v_float);
+      break;
+    case kSharpYuvTransferFunctionSmpte240:
+      linear = ToLinearSmpte240(v_float);
+      break;
+    case kSharpYuvTransferFunctionLinear:
+      return v;
+    case kSharpYuvTransferFunctionLog100:
+      linear = ToLinearLog100(v_float);
+      break;
+    case kSharpYuvTransferFunctionLog100_Sqrt10:
+      linear = ToLinearLog100Sqrt10(v_float);
+      break;
+    case kSharpYuvTransferFunctionIec61966:
+      linear = ToLinearIec61966(v_float);
+      break;
+    case kSharpYuvTransferFunctionBt1361:
+      linear = ToLinearBt1361(v_float);
+      break;
+    case kSharpYuvTransferFunctionSmpte2084:
+      linear = ToLinearPq(v_float);
+      break;
+    case kSharpYuvTransferFunctionSmpte428:
+      linear = ToLinearSmpte428(v_float);
+      break;
+    case kSharpYuvTransferFunctionHlg:
+      linear = ToLinearHlg(v_float);
+      break;
+    default:
+      assert(0);
+      linear = 0;
+      break;
+  }
+  return (uint32_t)Roundf(linear * ((1 << 16) - 1));
+}
+
+uint16_t SharpYuvLinearToGamma(uint32_t v, int bit_depth,
+                               SharpYuvTransferFunctionType transfer_type) {
+  float v_float, linear;
+  if (transfer_type == kSharpYuvTransferFunctionSrgb) {
+    return FromLinearSrgb(v, bit_depth);
+  }
+  v_float = (float)v / ((1 << 16) - 1);
+  switch (transfer_type) {
+    case kSharpYuvTransferFunctionBt709:
+    case kSharpYuvTransferFunctionBt601:
+    case kSharpYuvTransferFunctionBt2020_10Bit:
+    case kSharpYuvTransferFunctionBt2020_12Bit:
+      linear = FromLinear709(v_float);
+      break;
+    case kSharpYuvTransferFunctionBt470M:
+      linear = FromLinear470M(v_float);
+      break;
+    case kSharpYuvTransferFunctionBt470Bg:
+      linear = FromLinear470Bg(v_float);
+      break;
+    case kSharpYuvTransferFunctionSmpte240:
+      linear = FromLinearSmpte240(v_float);
+      break;
+    case kSharpYuvTransferFunctionLinear:
+      return v;
+    case kSharpYuvTransferFunctionLog100:
+      linear = FromLinearLog100(v_float);
+      break;
+    case kSharpYuvTransferFunctionLog100_Sqrt10:
+      linear = FromLinearLog100Sqrt10(v_float);
+      break;
+    case kSharpYuvTransferFunctionIec61966:
+      linear = FromLinearIec61966(v_float);
+      break;
+    case kSharpYuvTransferFunctionBt1361:
+      linear = FromLinearBt1361(v_float);
+      break;
+    case kSharpYuvTransferFunctionSmpte2084:
+      linear = FromLinearPq(v_float);
+      break;
+    case kSharpYuvTransferFunctionSmpte428:
+      linear = FromLinearSmpte428(v_float);
+      break;
+    case kSharpYuvTransferFunctionHlg:
+      linear = FromLinearHlg(v_float);
+      break;
+    default:
+      assert(0);
+      linear = 0;
+      break;
+  }
+  return (uint16_t)Roundf(linear * ((1 << bit_depth) - 1));
+}

sharpyuv/sharpyuv_gamma.h

@@ -0,0 +1,38 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Gamma correction utilities.
+
+#ifndef WEBP_SHARPYUV_SHARPYUV_GAMMA_H_
+#define WEBP_SHARPYUV_SHARPYUV_GAMMA_H_
+
+#include "sharpyuv/sharpyuv.h"
+#include "src/webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Initializes precomputed tables. Must be called once before calling
+// SharpYuvGammaToLinear or SharpYuvLinearToGamma.
+void SharpYuvInitGammaTables(void);
+
+// Converts a 'bit_depth'-bit gamma color value to a 16-bit linear value.
+uint32_t SharpYuvGammaToLinear(uint16_t v, int bit_depth,
+                               SharpYuvTransferFunctionType transfer_type);
+
+// Converts a 16-bit linear color value to a 'bit_depth'-bit gamma value.
+uint16_t SharpYuvLinearToGamma(uint32_t value, int bit_depth,
+                               SharpYuvTransferFunctionType transfer_type);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // WEBP_SHARPYUV_SHARPYUV_GAMMA_H_

sharpyuv/sharpyuv_neon.c

@@ -0,0 +1,181 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Speed-critical functions for Sharp YUV.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "sharpyuv/sharpyuv_dsp.h"
+
+#if defined(WEBP_USE_NEON)
+#include <assert.h>
+#include <stdlib.h>
+#include <arm_neon.h>
+
+static uint16_t clip_NEON(int v, int max) {
+  return (v < 0) ? 0 : (v > max) ? max : (uint16_t)v;
+}
+
+static uint64_t SharpYuvUpdateY_NEON(const uint16_t* ref, const uint16_t* src,
+                                     uint16_t* dst, int len, int bit_depth) {
+  const int max_y = (1 << bit_depth) - 1;
+  int i;
+  const int16x8_t zero = vdupq_n_s16(0);
+  const int16x8_t max = vdupq_n_s16(max_y);
+  uint64x2_t sum = vdupq_n_u64(0);
+  uint64_t diff;
+
+  for (i = 0; i + 8 <= len; i += 8) {
+    const int16x8_t A = vreinterpretq_s16_u16(vld1q_u16(ref + i));
+    const int16x8_t B = vreinterpretq_s16_u16(vld1q_u16(src + i));
+    const int16x8_t C = vreinterpretq_s16_u16(vld1q_u16(dst + i));
+    const int16x8_t D = vsubq_s16(A, B);       // diff_y
+    const int16x8_t F = vaddq_s16(C, D);       // new_y
+    const uint16x8_t H =
+        vreinterpretq_u16_s16(vmaxq_s16(vminq_s16(F, max), zero));
+    const int16x8_t I = vabsq_s16(D);          // abs(diff_y)
+    vst1q_u16(dst + i, H);
+    sum = vpadalq_u32(sum, vpaddlq_u16(vreinterpretq_u16_s16(I)));
+  }
+  diff = vgetq_lane_u64(sum, 0) + vgetq_lane_u64(sum, 1);
+  for (; i < len; ++i) {
+    const int diff_y = ref[i] - src[i];
+    const int new_y = (int)(dst[i]) + diff_y;
+    dst[i] = clip_NEON(new_y, max_y);
+    diff += (uint64_t)(abs(diff_y));
+  }
+  return diff;
+}
+
+static void SharpYuvUpdateRGB_NEON(const int16_t* ref, const int16_t* src,
+                                   int16_t* dst, int len) {
+  int i;
+  for (i = 0; i + 8 <= len; i += 8) {
+    const int16x8_t A = vld1q_s16(ref + i);
+    const int16x8_t B = vld1q_s16(src + i);
+    const int16x8_t C = vld1q_s16(dst + i);
+    const int16x8_t D = vsubq_s16(A, B);   // diff_uv
+    const int16x8_t E = vaddq_s16(C, D);   // new_uv
+    vst1q_s16(dst + i, E);
+  }
+  for (; i < len; ++i) {
+    const int diff_uv = ref[i] - src[i];
+    dst[i] += diff_uv;
+  }
+}
+
+static void SharpYuvFilterRow16_NEON(const int16_t* A, const int16_t* B,
+                                     int len, const uint16_t* best_y,
+                                     uint16_t* out, int bit_depth) {
+  const int max_y = (1 << bit_depth) - 1;
+  int i;
+  const int16x8_t max = vdupq_n_s16(max_y);
+  const int16x8_t zero = vdupq_n_s16(0);
+  for (i = 0; i + 8 <= len; i += 8) {
+    const int16x8_t a0 = vld1q_s16(A + i + 0);
+    const int16x8_t a1 = vld1q_s16(A + i + 1);
+    const int16x8_t b0 = vld1q_s16(B + i + 0);
+    const int16x8_t b1 = vld1q_s16(B + i + 1);
+    const int16x8_t a0b1 = vaddq_s16(a0, b1);
+    const int16x8_t a1b0 = vaddq_s16(a1, b0);
+    const int16x8_t a0a1b0b1 = vaddq_s16(a0b1, a1b0);  // A0+A1+B0+B1
+    const int16x8_t a0b1_2 = vaddq_s16(a0b1, a0b1);    // 2*(A0+B1)
+    const int16x8_t a1b0_2 = vaddq_s16(a1b0, a1b0);    // 2*(A1+B0)
+    const int16x8_t c0 = vshrq_n_s16(vaddq_s16(a0b1_2, a0a1b0b1), 3);
+    const int16x8_t c1 = vshrq_n_s16(vaddq_s16(a1b0_2, a0a1b0b1), 3);
+    const int16x8_t e0 = vrhaddq_s16(c1, a0);
+    const int16x8_t e1 = vrhaddq_s16(c0, a1);
+    const int16x8x2_t f = vzipq_s16(e0, e1);
+    const int16x8_t g0 = vreinterpretq_s16_u16(vld1q_u16(best_y + 2 * i + 0));
+    const int16x8_t g1 = vreinterpretq_s16_u16(vld1q_u16(best_y + 2 * i + 8));
+    const int16x8_t h0 = vaddq_s16(g0, f.val[0]);
+    const int16x8_t h1 = vaddq_s16(g1, f.val[1]);
+    const int16x8_t i0 = vmaxq_s16(vminq_s16(h0, max), zero);
+    const int16x8_t i1 = vmaxq_s16(vminq_s16(h1, max), zero);
+    vst1q_u16(out + 2 * i + 0, vreinterpretq_u16_s16(i0));
+    vst1q_u16(out + 2 * i + 8, vreinterpretq_u16_s16(i1));
+  }
+  for (; i < len; ++i) {
+    const int a0b1 = A[i + 0] + B[i + 1];
+    const int a1b0 = A[i + 1] + B[i + 0];
+    const int a0a1b0b1 = a0b1 + a1b0 + 8;
+    const int v0 = (8 * A[i + 0] + 2 * a1b0 + a0a1b0b1) >> 4;
+    const int v1 = (8 * A[i + 1] + 2 * a0b1 + a0a1b0b1) >> 4;
+    out[2 * i + 0] = clip_NEON(best_y[2 * i + 0] + v0, max_y);
+    out[2 * i + 1] = clip_NEON(best_y[2 * i + 1] + v1, max_y);
+  }
+}
+
+static void SharpYuvFilterRow32_NEON(const int16_t* A, const int16_t* B,
+                                     int len, const uint16_t* best_y,
+                                     uint16_t* out, int bit_depth) {
+  const int max_y = (1 << bit_depth) - 1;
+  int i;
+  const uint16x8_t max = vdupq_n_u16(max_y);
+  for (i = 0; i + 4 <= len; i += 4) {
+    const int16x4_t a0 = vld1_s16(A + i + 0);
+    const int16x4_t a1 = vld1_s16(A + i + 1);
+    const int16x4_t b0 = vld1_s16(B + i + 0);
+    const int16x4_t b1 = vld1_s16(B + i + 1);
+    const int32x4_t a0b1 = vaddl_s16(a0, b1);
+    const int32x4_t a1b0 = vaddl_s16(a1, b0);
+    const int32x4_t a0a1b0b1 = vaddq_s32(a0b1, a1b0);  // A0+A1+B0+B1
+    const int32x4_t a0b1_2 = vaddq_s32(a0b1, a0b1);    // 2*(A0+B1)
+    const int32x4_t a1b0_2 = vaddq_s32(a1b0, a1b0);    // 2*(A1+B0)
+    const int32x4_t c0 = vshrq_n_s32(vaddq_s32(a0b1_2, a0a1b0b1), 3);
+    const int32x4_t c1 = vshrq_n_s32(vaddq_s32(a1b0_2, a0a1b0b1), 3);
+    const int32x4_t e0 = vrhaddq_s32(c1, vmovl_s16(a0));
+    const int32x4_t e1 = vrhaddq_s32(c0, vmovl_s16(a1));
+    const int32x4x2_t f = vzipq_s32(e0, e1);
+
+    const int16x8_t g = vreinterpretq_s16_u16(vld1q_u16(best_y + 2 * i));
+    const int32x4_t h0 = vaddw_s16(f.val[0], vget_low_s16(g));
+    const int32x4_t h1 = vaddw_s16(f.val[1], vget_high_s16(g));
+    const uint16x8_t i_16 = vcombine_u16(vqmovun_s32(h0), vqmovun_s32(h1));
+    const uint16x8_t i_clamped = vminq_u16(i_16, max);
+    vst1q_u16(out + 2 * i + 0, i_clamped);
+  }
+  for (; i < len; ++i) {
+    const int a0b1 = A[i + 0] + B[i + 1];
+    const int a1b0 = A[i + 1] + B[i + 0];
+    const int a0a1b0b1 = a0b1 + a1b0 + 8;
+    const int v0 = (8 * A[i + 0] + 2 * a1b0 + a0a1b0b1) >> 4;
+    const int v1 = (8 * A[i + 1] + 2 * a0b1 + a0a1b0b1) >> 4;
+    out[2 * i + 0] = clip_NEON(best_y[2 * i + 0] + v0, max_y);
+    out[2 * i + 1] = clip_NEON(best_y[2 * i + 1] + v1, max_y);
+  }
+}
+
+static void SharpYuvFilterRow_NEON(const int16_t* A, const int16_t* B, int len,
+                                   const uint16_t* best_y, uint16_t* out,
+                                   int bit_depth) {
+  if (bit_depth <= 10) {
+    SharpYuvFilterRow16_NEON(A, B, len, best_y, out, bit_depth);
+  } else {
+    SharpYuvFilterRow32_NEON(A, B, len, best_y, out, bit_depth);
+  }
+}
+
+//------------------------------------------------------------------------------
+
+extern void InitSharpYuvNEON(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void InitSharpYuvNEON(void) {
+  SharpYuvUpdateY = SharpYuvUpdateY_NEON;
+  SharpYuvUpdateRGB = SharpYuvUpdateRGB_NEON;
+  SharpYuvFilterRow = SharpYuvFilterRow_NEON;
+}
+
+#else  // !WEBP_USE_NEON
+
+extern void InitSharpYuvNEON(void);
+
+void InitSharpYuvNEON(void) {}
+
+#endif  // WEBP_USE_NEON

sharpyuv/sharpyuv_sse2.c

@@ -0,0 +1,201 @@
+// Copyright 2022 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Speed-critical functions for Sharp YUV.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "sharpyuv/sharpyuv_dsp.h"
+
+#if defined(WEBP_USE_SSE2)
+#include <stdlib.h>
+#include <emmintrin.h>
+
+static uint16_t clip_SSE2(int v, int max) {
+  return (v < 0) ? 0 : (v > max) ? max : (uint16_t)v;
+}
+
+static uint64_t SharpYuvUpdateY_SSE2(const uint16_t* ref, const uint16_t* src,
+                                     uint16_t* dst, int len, int bit_depth) {
+  const int max_y = (1 << bit_depth) - 1;
+  uint64_t diff = 0;
+  uint32_t tmp[4];
+  int i;
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i max = _mm_set1_epi16(max_y);
+  const __m128i one = _mm_set1_epi16(1);
+  __m128i sum = zero;
+
+  for (i = 0; i + 8 <= len; i += 8) {
+    const __m128i A = _mm_loadu_si128((const __m128i*)(ref + i));
+    const __m128i B = _mm_loadu_si128((const __m128i*)(src + i));
+    const __m128i C = _mm_loadu_si128((const __m128i*)(dst + i));
+    const __m128i D = _mm_sub_epi16(A, B);       // diff_y
+    const __m128i E = _mm_cmpgt_epi16(zero, D);  // sign (-1 or 0)
+    const __m128i F = _mm_add_epi16(C, D);       // new_y
+    const __m128i G = _mm_or_si128(E, one);      // -1 or 1
+    const __m128i H = _mm_max_epi16(_mm_min_epi16(F, max), zero);
+    const __m128i I = _mm_madd_epi16(D, G);      // sum(abs(...))
+    _mm_storeu_si128((__m128i*)(dst + i), H);
+    sum = _mm_add_epi32(sum, I);
+  }
+  _mm_storeu_si128((__m128i*)tmp, sum);
+  diff = tmp[3] + tmp[2] + tmp[1] + tmp[0];
+  for (; i < len; ++i) {
+    const int diff_y = ref[i] - src[i];
+    const int new_y = (int)dst[i] + diff_y;
+    dst[i] = clip_SSE2(new_y, max_y);
+    diff += (uint64_t)abs(diff_y);
+  }
+  return diff;
+}
+
+static void SharpYuvUpdateRGB_SSE2(const int16_t* ref, const int16_t* src,
+                                   int16_t* dst, int len) {
+  int i = 0;
+  for (i = 0; i + 8 <= len; i += 8) {
+    const __m128i A = _mm_loadu_si128((const __m128i*)(ref + i));
+    const __m128i B = _mm_loadu_si128((const __m128i*)(src + i));
+    const __m128i C = _mm_loadu_si128((const __m128i*)(dst + i));
+    const __m128i D = _mm_sub_epi16(A, B);   // diff_uv
+    const __m128i E = _mm_add_epi16(C, D);   // new_uv
+    _mm_storeu_si128((__m128i*)(dst + i), E);
+  }
+  for (; i < len; ++i) {
+    const int diff_uv = ref[i] - src[i];
+    dst[i] += diff_uv;
+  }
+}
+
+static void SharpYuvFilterRow16_SSE2(const int16_t* A, const int16_t* B,
+                                     int len, const uint16_t* best_y,
+                                     uint16_t* out, int bit_depth) {
+  const int max_y = (1 << bit_depth) - 1;
+  int i;
+  const __m128i kCst8 = _mm_set1_epi16(8);
+  const __m128i max = _mm_set1_epi16(max_y);
+  const __m128i zero = _mm_setzero_si128();
+  for (i = 0; i + 8 <= len; i += 8) {
+    const __m128i a0 = _mm_loadu_si128((const __m128i*)(A + i + 0));
+    const __m128i a1 = _mm_loadu_si128((const __m128i*)(A + i + 1));
+    const __m128i b0 = _mm_loadu_si128((const __m128i*)(B + i + 0));
+    const __m128i b1 = _mm_loadu_si128((const __m128i*)(B + i + 1));
+    const __m128i a0b1 = _mm_add_epi16(a0, b1);
+    const __m128i a1b0 = _mm_add_epi16(a1, b0);
+    const __m128i a0a1b0b1 = _mm_add_epi16(a0b1, a1b0);  // A0+A1+B0+B1
+    const __m128i a0a1b0b1_8 = _mm_add_epi16(a0a1b0b1, kCst8);
+    const __m128i a0b1_2 = _mm_add_epi16(a0b1, a0b1);    // 2*(A0+B1)
+    const __m128i a1b0_2 = _mm_add_epi16(a1b0, a1b0);    // 2*(A1+B0)
+    const __m128i c0 = _mm_srai_epi16(_mm_add_epi16(a0b1_2, a0a1b0b1_8), 3);
+    const __m128i c1 = _mm_srai_epi16(_mm_add_epi16(a1b0_2, a0a1b0b1_8), 3);
+    const __m128i d0 = _mm_add_epi16(c1, a0);
+    const __m128i d1 = _mm_add_epi16(c0, a1);
+    const __m128i e0 = _mm_srai_epi16(d0, 1);
+    const __m128i e1 = _mm_srai_epi16(d1, 1);
+    const __m128i f0 = _mm_unpacklo_epi16(e0, e1);
+    const __m128i f1 = _mm_unpackhi_epi16(e0, e1);
+    const __m128i g0 = _mm_loadu_si128((const __m128i*)(best_y + 2 * i + 0));
+    const __m128i g1 = _mm_loadu_si128((const __m128i*)(best_y + 2 * i + 8));
+    const __m128i h0 = _mm_add_epi16(g0, f0);
+    const __m128i h1 = _mm_add_epi16(g1, f1);
+    const __m128i i0 = _mm_max_epi16(_mm_min_epi16(h0, max), zero);
+    const __m128i i1 = _mm_max_epi16(_mm_min_epi16(h1, max), zero);
+    _mm_storeu_si128((__m128i*)(out + 2 * i + 0), i0);
+    _mm_storeu_si128((__m128i*)(out + 2 * i + 8), i1);
+  }
+  for (; i < len; ++i) {
+    //   (9 * A0 + 3 * A1 + 3 * B0 + B1 + 8) >> 4 =
+    // = (8 * A0 + 2 * (A1 + B0) + (A0 + A1 + B0 + B1 + 8)) >> 4
+    // We reuse the common sub-expressions.
+    const int a0b1 = A[i + 0] + B[i + 1];
+    const int a1b0 = A[i + 1] + B[i + 0];
+    const int a0a1b0b1 = a0b1 + a1b0 + 8;
+    const int v0 = (8 * A[i + 0] + 2 * a1b0 + a0a1b0b1) >> 4;
+    const int v1 = (8 * A[i + 1] + 2 * a0b1 + a0a1b0b1) >> 4;
+    out[2 * i + 0] = clip_SSE2(best_y[2 * i + 0] + v0, max_y);
+    out[2 * i + 1] = clip_SSE2(best_y[2 * i + 1] + v1, max_y);
+  }
+}
+
+static WEBP_INLINE __m128i s16_to_s32(__m128i in) {
+  return _mm_srai_epi32(_mm_unpacklo_epi16(in, in), 16);
+}
+
+static void SharpYuvFilterRow32_SSE2(const int16_t* A, const int16_t* B,
+                                     int len, const uint16_t* best_y,
+                                     uint16_t* out, int bit_depth) {
+  const int max_y = (1 << bit_depth) - 1;
+  int i;
+  const __m128i kCst8 = _mm_set1_epi32(8);
+  const __m128i max = _mm_set1_epi16(max_y);
+  const __m128i zero = _mm_setzero_si128();
+  for (i = 0; i + 4 <= len; i += 4) {
+    const __m128i a0 = s16_to_s32(_mm_loadl_epi64((const __m128i*)(A + i + 0)));
+    const __m128i a1 = s16_to_s32(_mm_loadl_epi64((const __m128i*)(A + i + 1)));
+    const __m128i b0 = s16_to_s32(_mm_loadl_epi64((const __m128i*)(B + i + 0)));
+    const __m128i b1 = s16_to_s32(_mm_loadl_epi64((const __m128i*)(B + i + 1)));
+    const __m128i a0b1 = _mm_add_epi32(a0, b1);
+    const __m128i a1b0 = _mm_add_epi32(a1, b0);
+    const __m128i a0a1b0b1 = _mm_add_epi32(a0b1, a1b0);  // A0+A1+B0+B1
+    const __m128i a0a1b0b1_8 = _mm_add_epi32(a0a1b0b1, kCst8);
+    const __m128i a0b1_2 = _mm_add_epi32(a0b1, a0b1);  // 2*(A0+B1)
+    const __m128i a1b0_2 = _mm_add_epi32(a1b0, a1b0);  // 2*(A1+B0)
+    const __m128i c0 = _mm_srai_epi32(_mm_add_epi32(a0b1_2, a0a1b0b1_8), 3);
+    const __m128i c1 = _mm_srai_epi32(_mm_add_epi32(a1b0_2, a0a1b0b1_8), 3);
+    const __m128i d0 = _mm_add_epi32(c1, a0);
+    const __m128i d1 = _mm_add_epi32(c0, a1);
+    const __m128i e0 = _mm_srai_epi32(d0, 1);
+    const __m128i e1 = _mm_srai_epi32(d1, 1);
+    const __m128i f0 = _mm_unpacklo_epi32(e0, e1);
+    const __m128i f1 = _mm_unpackhi_epi32(e0, e1);
+    const __m128i g = _mm_loadu_si128((const __m128i*)(best_y + 2 * i + 0));
+    const __m128i h_16 = _mm_add_epi16(g, _mm_packs_epi32(f0, f1));
+    const __m128i final = _mm_max_epi16(_mm_min_epi16(h_16, max), zero);
+    _mm_storeu_si128((__m128i*)(out + 2 * i + 0), final);
+  }
+  for (; i < len; ++i) {
+    //   (9 * A0 + 3 * A1 + 3 * B0 + B1 + 8) >> 4 =
+    // = (8 * A0 + 2 * (A1 + B0) + (A0 + A1 + B0 + B1 + 8)) >> 4
+    // We reuse the common sub-expressions.
+    const int a0b1 = A[i + 0] + B[i + 1];
+    const int a1b0 = A[i + 1] + B[i + 0];
+    const int a0a1b0b1 = a0b1 + a1b0 + 8;
+    const int v0 = (8 * A[i + 0] + 2 * a1b0 + a0a1b0b1) >> 4;
+    const int v1 = (8 * A[i + 1] + 2 * a0b1 + a0a1b0b1) >> 4;
+    out[2 * i + 0] = clip_SSE2(best_y[2 * i + 0] + v0, max_y);
+    out[2 * i + 1] = clip_SSE2(best_y[2 * i + 1] + v1, max_y);
+  }
+}
+
+static void SharpYuvFilterRow_SSE2(const int16_t* A, const int16_t* B, int len,
+                                   const uint16_t* best_y, uint16_t* out,
+                                   int bit_depth) {
+  if (bit_depth <= 10) {
+    SharpYuvFilterRow16_SSE2(A, B, len, best_y, out, bit_depth);
+  } else {
+    SharpYuvFilterRow32_SSE2(A, B, len, best_y, out, bit_depth);
+  }
+}
+
+//------------------------------------------------------------------------------
+
+extern void InitSharpYuvSSE2(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void InitSharpYuvSSE2(void) {
+  SharpYuvUpdateY = SharpYuvUpdateY_SSE2;
+  SharpYuvUpdateRGB = SharpYuvUpdateRGB_SSE2;
+  SharpYuvFilterRow = SharpYuvFilterRow_SSE2;
+}
+#else  // !WEBP_USE_SSE2
+
+extern void InitSharpYuvSSE2(void);
+
+void InitSharpYuvSSE2(void) {}
+
+#endif  // WEBP_USE_SSE2

src/Makefile.am

@@ -36,7 +36,7 @@ libwebp_la_LIBADD += utils/libwebputils.la
 # other than the ones listed on the command line, i.e., after linking, it will
 # not have unresolved symbols. Some platforms (Windows among them) require all
 # symbols in shared libraries to be resolved at library creation.
-libwebp_la_LDFLAGS = -no-undefined -version-info 8:3:1
+libwebp_la_LDFLAGS = -no-undefined -version-info 8:9:1
 libwebpincludedir = $(includedir)/webp
 pkgconfig_DATA = libwebp.pc
 
@@ -48,7 +48,7 @@ if BUILD_LIBWEBPDECODER
   libwebpdecoder_la_LIBADD += dsp/libwebpdspdecode.la
   libwebpdecoder_la_LIBADD += utils/libwebputilsdecode.la
 
-  libwebpdecoder_la_LDFLAGS = -no-undefined -version-info 4:3:1
+  libwebpdecoder_la_LDFLAGS = -no-undefined -version-info 4:9:1
   pkgconfig_DATA += libwebpdecoder.pc
 endif
 

src/dec/alpha_dec.c

@@ -13,18 +13,20 @@
 
 #include <stdlib.h>
 #include "src/dec/alphai_dec.h"
+#include "src/dec/vp8_dec.h"
 #include "src/dec/vp8i_dec.h"
 #include "src/dec/vp8li_dec.h"
 #include "src/dsp/dsp.h"
 #include "src/utils/quant_levels_dec_utils.h"
 #include "src/utils/utils.h"
 #include "src/webp/format_constants.h"
+#include "src/webp/types.h"
 
 //------------------------------------------------------------------------------
 // ALPHDecoder object.
 
 // Allocates a new alpha decoder instance.
-static ALPHDecoder* ALPHNew(void) {
+WEBP_NODISCARD static ALPHDecoder* ALPHNew(void) {
   ALPHDecoder* const dec = (ALPHDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec));
   return dec;
 }
@@ -45,9 +47,9 @@ static void ALPHDelete(ALPHDecoder* const dec) {
 // header for alpha data stored using lossless compression.
 // Returns false in case of error in alpha header (data too short, invalid
 // compression method or filter, error in lossless header data etc).
-static int ALPHInit(ALPHDecoder* const dec, const uint8_t* data,
-                    size_t data_size, const VP8Io* const src_io,
-                    uint8_t* output) {
+WEBP_NODISCARD static int ALPHInit(ALPHDecoder* const dec, const uint8_t* data,
+                                   size_t data_size, const VP8Io* const src_io,
+                                   uint8_t* output) {
   int ok = 0;
   const uint8_t* const alpha_data = data + ALPHA_HEADER_LEN;
   const size_t alpha_data_size = data_size - ALPHA_HEADER_LEN;
@@ -79,7 +81,9 @@ static int ALPHInit(ALPHDecoder* const dec, const uint8_t* data,
   }
 
   // Copy the necessary parameters from src_io to io
-  VP8InitIo(io);
+  if (!VP8InitIo(io)) {
+    return 0;
+  }
   WebPInitCustomIo(NULL, io);
   io->opaque = dec;
   io->width = src_io->width;
@@ -107,7 +111,8 @@ static int ALPHInit(ALPHDecoder* const dec, const uint8_t* data,
 // starting from row number 'row'. It assumes that rows up to (row - 1) have
 // already been decoded.
 // Returns false in case of bitstream error.
-static int ALPHDecode(VP8Decoder* const dec, int row, int num_rows) {
+WEBP_NODISCARD static int ALPHDecode(VP8Decoder* const dec, int row,
+                                     int num_rows) {
   ALPHDecoder* const alph_dec = dec->alph_dec_;
   const int width = alph_dec->width_;
   const int height = alph_dec->io_.crop_bottom;
@@ -117,21 +122,12 @@ static int ALPHDecode(VP8Decoder* const dec, int row, int num_rows) {
     const uint8_t* deltas = dec->alpha_data_ + ALPHA_HEADER_LEN + row * width;
     uint8_t* dst = dec->alpha_plane_ + row * width;
     assert(deltas <= &dec->alpha_data_[dec->alpha_data_size_]);
-    if (alph_dec->filter_ != WEBP_FILTER_NONE) {
-      assert(WebPUnfilters[alph_dec->filter_] != NULL);
-      for (y = 0; y < num_rows; ++y) {
-        WebPUnfilters[alph_dec->filter_](prev_line, deltas, dst, width);
-        prev_line = dst;
-        dst += width;
-        deltas += width;
-      }
-    } else {
-      for (y = 0; y < num_rows; ++y) {
-        memcpy(dst, deltas, width * sizeof(*dst));
-        prev_line = dst;
-        dst += width;
-        deltas += width;
-      }
+    assert(WebPUnfilters[alph_dec->filter_] != NULL);
+    for (y = 0; y < num_rows; ++y) {
+      WebPUnfilters[alph_dec->filter_](prev_line, deltas, dst, width);
+      prev_line = dst;
+      dst += width;
+      deltas += width;
     }
     dec->alpha_prev_line_ = prev_line;
   } else {  // alph_dec->method_ == ALPHA_LOSSLESS_COMPRESSION
@@ -147,7 +143,8 @@ static int ALPHDecode(VP8Decoder* const dec, int row, int num_rows) {
   return 1;
 }
 
-static int AllocateAlphaPlane(VP8Decoder* const dec, const VP8Io* const io) {
+WEBP_NODISCARD static int AllocateAlphaPlane(VP8Decoder* const dec,
+                                             const VP8Io* const io) {
   const int stride = io->width;
   const int height = io->crop_bottom;
   const uint64_t alpha_size = (uint64_t)stride * height;
@@ -155,7 +152,8 @@ static int AllocateAlphaPlane(VP8Decoder* const dec, const VP8Io* const io) {
   dec->alpha_plane_mem_ =
       (uint8_t*)WebPSafeMalloc(alpha_size, sizeof(*dec->alpha_plane_));
   if (dec->alpha_plane_mem_ == NULL) {
-    return 0;
+    return VP8SetError(dec, VP8_STATUS_OUT_OF_MEMORY,
+                       "Alpha decoder initialization failed.");
   }
   dec->alpha_plane_ = dec->alpha_plane_mem_;
   dec->alpha_prev_line_ = NULL;
@@ -174,9 +172,9 @@ void WebPDeallocateAlphaMemory(VP8Decoder* const dec) {
 //------------------------------------------------------------------------------
 // Main entry point.
 
-const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
-                                      const VP8Io* const io,
-                                      int row, int num_rows) {
+WEBP_NODISCARD const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
+                                                     const VP8Io* const io,
+                                                     int row, int num_rows) {
   const int width = io->width;
   const int height = io->crop_bottom;
 
@@ -189,10 +187,19 @@ const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
   if (!dec->is_alpha_decoded_) {
     if (dec->alph_dec_ == NULL) {    // Initialize decoder.
       dec->alph_dec_ = ALPHNew();
-      if (dec->alph_dec_ == NULL) return NULL;
+      if (dec->alph_dec_ == NULL) {
+        VP8SetError(dec, VP8_STATUS_OUT_OF_MEMORY,
+                    "Alpha decoder initialization failed.");
+        return NULL;
+      }
       if (!AllocateAlphaPlane(dec, io)) goto Error;
       if (!ALPHInit(dec->alph_dec_, dec->alpha_data_, dec->alpha_data_size_,
                     io, dec->alpha_plane_)) {
+        VP8LDecoder* const vp8l_dec = dec->alph_dec_->vp8l_dec_;
+        VP8SetError(dec,
+                    (vp8l_dec == NULL) ? VP8_STATUS_OUT_OF_MEMORY
+                                       : vp8l_dec->status_,
+                    "Alpha decoder initialization failed.");
         goto Error;
       }
       // if we allowed use of alpha dithering, check whether it's needed at all

src/dec/buffer_dec.c

@@ -75,7 +75,7 @@ static VP8StatusCode CheckDecBuffer(const WebPDecBuffer* const buffer) {
     const WebPRGBABuffer* const buf = &buffer->u.RGBA;
     const int stride = abs(buf->stride);
     const uint64_t size =
-        MIN_BUFFER_SIZE(width * kModeBpp[mode], height, stride);
+        MIN_BUFFER_SIZE((uint64_t)width * kModeBpp[mode], height, stride);
     ok &= (size <= buf->size);
     ok &= (stride >= width * kModeBpp[mode]);
     ok &= (buf->rgba != NULL);

src/dec/idec_dec.c

@@ -17,8 +17,10 @@
 
 #include "src/dec/alphai_dec.h"
 #include "src/dec/webpi_dec.h"
+#include "src/dec/vp8_dec.h"
 #include "src/dec/vp8i_dec.h"
 #include "src/utils/utils.h"
+#include "src/webp/decode.h"
 
 // In append mode, buffer allocations increase as multiples of this value.
 // Needs to be a power of 2.
@@ -161,8 +163,9 @@ static void DoRemap(WebPIDecoder* const idec, ptrdiff_t offset) {
 
 // Appends data to the end of MemBuffer->buf_. It expands the allocated memory
 // size if required and also updates VP8BitReader's if new memory is allocated.
-static int AppendToMemBuffer(WebPIDecoder* const idec,
-                             const uint8_t* const data, size_t data_size) {
+WEBP_NODISCARD static int AppendToMemBuffer(WebPIDecoder* const idec,
+                                            const uint8_t* const data,
+                                            size_t data_size) {
   VP8Decoder* const dec = (VP8Decoder*)idec->dec_;
   MemBuffer* const mem = &idec->mem_;
   const int need_compressed_alpha = NeedCompressedAlpha(idec);
@@ -203,8 +206,9 @@ static int AppendToMemBuffer(WebPIDecoder* const idec,
   return 1;
 }
 
-static int RemapMemBuffer(WebPIDecoder* const idec,
-                          const uint8_t* const data, size_t data_size) {
+WEBP_NODISCARD static int RemapMemBuffer(WebPIDecoder* const idec,
+                                         const uint8_t* const data,
+                                         size_t data_size) {
   MemBuffer* const mem = &idec->mem_;
   const uint8_t* const old_buf = mem->buf_;
   const uint8_t* const old_start =
@@ -237,7 +241,8 @@ static void ClearMemBuffer(MemBuffer* const mem) {
   }
 }
 
-static int CheckMemBufferMode(MemBuffer* const mem, MemBufferMode expected) {
+WEBP_NODISCARD static int CheckMemBufferMode(MemBuffer* const mem,
+                                             MemBufferMode expected) {
   if (mem->mode_ == MEM_MODE_NONE) {
     mem->mode_ = expected;    // switch to the expected mode
   } else if (mem->mode_ != expected) {
@@ -248,7 +253,7 @@ static int CheckMemBufferMode(MemBuffer* const mem, MemBufferMode expected) {
 }
 
 // To be called last.
-static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) {
+WEBP_NODISCARD static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) {
   const WebPDecoderOptions* const options = idec->params_.options;
   WebPDecBuffer* const output = idec->params_.output;
 
@@ -258,8 +263,10 @@ static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) {
     if (status != VP8_STATUS_OK) return status;
   }
   if (idec->final_output_ != NULL) {
-    WebPCopyDecBufferPixels(output, idec->final_output_);  // do the slow-copy
+    const VP8StatusCode status = WebPCopyDecBufferPixels(
+        output, idec->final_output_);  // do the slow-copy
     WebPFreeDecBuffer(&idec->output_);
+    if (status != VP8_STATUS_OK) return status;
     *output = *idec->final_output_;
     idec->final_output_ = NULL;
   }
@@ -288,7 +295,7 @@ static void RestoreContext(const MBContext* context, VP8Decoder* const dec,
 static VP8StatusCode IDecError(WebPIDecoder* const idec, VP8StatusCode error) {
   if (idec->state_ == STATE_VP8_DATA) {
     // Synchronize the thread, clean-up and check for errors.
-    VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_);
+    (void)VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_);
   }
   idec->state_ = STATE_ERROR;
   return error;
@@ -329,6 +336,7 @@ static VP8StatusCode DecodeWebPHeaders(WebPIDecoder* const idec) {
     if (dec == NULL) {
       return VP8_STATUS_OUT_OF_MEMORY;
     }
+    dec->incremental_ = 1;
     idec->dec_ = dec;
     dec->alpha_data_ = headers.alpha_data;
     dec->alpha_data_size_ = headers.alpha_data_size;
@@ -601,8 +609,9 @@ static VP8StatusCode IDecode(WebPIDecoder* idec) {
 //------------------------------------------------------------------------------
 // Internal constructor
 
-static WebPIDecoder* NewDecoder(WebPDecBuffer* const output_buffer,
-                                const WebPBitstreamFeatures* const features) {
+WEBP_NODISCARD static WebPIDecoder* NewDecoder(
+    WebPDecBuffer* const output_buffer,
+    const WebPBitstreamFeatures* const features) {
   WebPIDecoder* idec = (WebPIDecoder*)WebPSafeCalloc(1ULL, sizeof(*idec));
   if (idec == NULL) {
     return NULL;
@@ -614,8 +623,10 @@ static WebPIDecoder* NewDecoder(WebPDecBuffer* const output_buffer,
   idec->last_mb_y_ = -1;
 
   InitMemBuffer(&idec->mem_);
-  WebPInitDecBuffer(&idec->output_);
-  VP8InitIo(&idec->io_);
+  if (!WebPInitDecBuffer(&idec->output_) || !VP8InitIo(&idec->io_)) {
+    WebPSafeFree(idec);
+    return NULL;
+  }
 
   WebPResetDecParams(&idec->params_);
   if (output_buffer == NULL || WebPAvoidSlowMemory(output_buffer, features)) {
@@ -674,7 +685,8 @@ void WebPIDelete(WebPIDecoder* idec) {
     if (!idec->is_lossless_) {
       if (idec->state_ == STATE_VP8_DATA) {
         // Synchronize the thread, clean-up and check for errors.
-        VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_);
+        // TODO(vrabaud) do we care about the return result?
+        (void)VP8ExitCritical((VP8Decoder*)idec->dec_, &idec->io_);
       }
       VP8Delete((VP8Decoder*)idec->dec_);
     } else {
@@ -851,8 +863,8 @@ const WebPDecBuffer* WebPIDecodedArea(const WebPIDecoder* idec,
   return src;
 }
 
-uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int* last_y,
-                        int* width, int* height, int* stride) {
+WEBP_NODISCARD uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int* last_y,
+                                       int* width, int* height, int* stride) {
   const WebPDecBuffer* const src = GetOutputBuffer(idec);
   if (src == NULL) return NULL;
   if (src->colorspace >= MODE_YUV) {
@@ -867,10 +879,10 @@ uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int* last_y,
   return src->u.RGBA.rgba;
 }
 
-uint8_t* WebPIDecGetYUVA(const WebPIDecoder* idec, int* last_y,
-                         uint8_t** u, uint8_t** v, uint8_t** a,
-                         int* width, int* height,
-                         int* stride, int* uv_stride, int* a_stride) {
+WEBP_NODISCARD uint8_t* WebPIDecGetYUVA(const WebPIDecoder* idec, int* last_y,
+                                        uint8_t** u, uint8_t** v, uint8_t** a,
+                                        int* width, int* height, int* stride,
+                                        int* uv_stride, int* a_stride) {
   const WebPDecBuffer* const src = GetOutputBuffer(idec);
   if (src == NULL) return NULL;
   if (src->colorspace < MODE_YUV) {

src/dec/tree_dec.c

@@ -12,10 +12,12 @@
 // Author: Skal (pascal.massimino@gmail.com)
 
 #include "src/dec/vp8i_dec.h"
+#include "src/dsp/cpu.h"
 #include "src/utils/bit_reader_inl_utils.h"
 
 #if !defined(USE_GENERIC_TREE)
-#if !defined(__arm__) && !defined(_M_ARM) && !defined(__aarch64__)
+#if !defined(__arm__) && !defined(_M_ARM) && !WEBP_AARCH64 && \
+    !defined(__wasm__)
 // using a table is ~1-2% slower on ARM. Prefer the coded-tree approach then.
 #define USE_GENERIC_TREE 1   // ALTERNATE_CODE
 #else

src/dec/vp8_dec.c

@@ -86,6 +86,8 @@ void VP8Delete(VP8Decoder* const dec) {
 
 int VP8SetError(VP8Decoder* const dec,
                 VP8StatusCode error, const char* const msg) {
+  // VP8_STATUS_SUSPENDED is only meaningful in incremental decoding.
+  assert(dec->incremental_ || error != VP8_STATUS_SUSPENDED);
   // The oldest error reported takes precedence over the new one.
   if (dec->status_ == VP8_STATUS_OK) {
     dec->status_ = error;
@@ -190,12 +192,12 @@ static int ParseSegmentHeader(VP8BitReader* br,
 }
 
 // Paragraph 9.5
-// This function returns VP8_STATUS_SUSPENDED if we don't have all the
-// necessary data in 'buf'.
-// This case is not necessarily an error (for incremental decoding).
-// Still, no bitreader is ever initialized to make it possible to read
-// unavailable memory.
-// If we don't even have the partitions' sizes, than VP8_STATUS_NOT_ENOUGH_DATA
+// If we don't have all the necessary data in 'buf', this function returns
+// VP8_STATUS_SUSPENDED in incremental decoding, VP8_STATUS_NOT_ENOUGH_DATA
+// otherwise.
+// In incremental decoding, this case is not necessarily an error. Still, no
+// bitreader is ever initialized to make it possible to read unavailable memory.
+// If we don't even have the partitions' sizes, then VP8_STATUS_NOT_ENOUGH_DATA
 // is returned, and this is an unrecoverable error.
 // If the partitions were positioned ok, VP8_STATUS_OK is returned.
 static VP8StatusCode ParsePartitions(VP8Decoder* const dec,
@@ -225,8 +227,10 @@ static VP8StatusCode ParsePartitions(VP8Decoder* const dec,
     sz += 3;
   }
   VP8InitBitReader(dec->parts_ + last_part, part_start, size_left);
-  return (part_start < buf_end) ? VP8_STATUS_OK :
-           VP8_STATUS_SUSPENDED;   // Init is ok, but there's not enough data
+  if (part_start < buf_end) return VP8_STATUS_OK;
+  return dec->incremental_
+             ? VP8_STATUS_SUSPENDED  // Init is ok, but there's not enough data
+             : VP8_STATUS_NOT_ENOUGH_DATA;
 }
 
 // Paragraph 9.4
@@ -494,6 +498,8 @@ static int GetCoeffsAlt(VP8BitReader* const br,
   return 16;
 }
 
+extern VP8CPUInfo VP8GetCPUInfo;
+
 WEBP_DSP_INIT_FUNC(InitGetCoeffs) {
   if (VP8GetCPUInfo != NULL && VP8GetCPUInfo(kSlowSSSE3)) {
     GetCoeffs = GetCoeffsAlt;

src/dec/vp8_dec.h

@@ -15,6 +15,7 @@
 #define WEBP_DEC_VP8_DEC_H_
 
 #include "src/webp/decode.h"
+#include "src/webp/types.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -108,16 +109,14 @@ struct VP8Io {
 };
 
 // Internal, version-checked, entry point
-int VP8InitIoInternal(VP8Io* const, int);
+WEBP_NODISCARD int VP8InitIoInternal(VP8Io* const, int);
 
 // Set the custom IO function pointers and user-data. The setter for IO hooks
 // should be called before initiating incremental decoding. Returns true if
 // WebPIDecoder object is successfully modified, false otherwise.
-int WebPISetIOHooks(WebPIDecoder* const idec,
-                    VP8IoPutHook put,
-                    VP8IoSetupHook setup,
-                    VP8IoTeardownHook teardown,
-                    void* user_data);
+WEBP_NODISCARD int WebPISetIOHooks(WebPIDecoder* const idec, VP8IoPutHook put,
+                                   VP8IoSetupHook setup,
+                                   VP8IoTeardownHook teardown, void* user_data);
 
 // Main decoding object. This is an opaque structure.
 typedef struct VP8Decoder VP8Decoder;
@@ -128,17 +127,17 @@ VP8Decoder* VP8New(void);
 // Must be called to make sure 'io' is initialized properly.
 // Returns false in case of version mismatch. Upon such failure, no other
 // decoding function should be called (VP8Decode, VP8GetHeaders, ...)
-static WEBP_INLINE int VP8InitIo(VP8Io* const io) {
+WEBP_NODISCARD static WEBP_INLINE int VP8InitIo(VP8Io* const io) {
   return VP8InitIoInternal(io, WEBP_DECODER_ABI_VERSION);
 }
 
 // Decode the VP8 frame header. Returns true if ok.
 // Note: 'io->data' must be pointing to the start of the VP8 frame header.
-int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io);
+WEBP_NODISCARD int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io);
 
 // Decode a picture. Will call VP8GetHeaders() if it wasn't done already.
 // Returns false in case of error.
-int VP8Decode(VP8Decoder* const dec, VP8Io* const io);
+WEBP_NODISCARD int VP8Decode(VP8Decoder* const dec, VP8Io* const io);
 
 // Return current status of the decoder:
 VP8StatusCode VP8Status(VP8Decoder* const dec);

src/dec/vp8i_dec.h

@@ -21,6 +21,7 @@
 #include "src/utils/random_utils.h"
 #include "src/utils/thread_utils.h"
 #include "src/dsp/dsp.h"
+#include "src/webp/types.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -31,8 +32,8 @@ extern "C" {
 
 // version numbers
 #define DEC_MAJ_VERSION 1
-#define DEC_MIN_VERSION 2
-#define DEC_REV_VERSION 2
+#define DEC_MIN_VERSION 4
+#define DEC_REV_VERSION 0
 
 // YUV-cache parameters. Cache is 32-bytes wide (= one cacheline).
 // Constraints are: We need to store one 16x16 block of luma samples (y),
@@ -186,6 +187,7 @@ struct VP8Decoder {
 
   // Main data source
   VP8BitReader br_;
+  int incremental_;  // if true, incremental decoding is expected
 
   // headers
   VP8FrameHeader   frm_hdr_;
@@ -281,7 +283,7 @@ int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec);
 void VP8ParseQuant(VP8Decoder* const dec);
 
 // in frame.c
-int VP8InitFrame(VP8Decoder* const dec, VP8Io* const io);
+WEBP_NODISCARD int VP8InitFrame(VP8Decoder* const dec, VP8Io* const io);
 // Call io->setup() and finish setting up scan parameters.
 // After this call returns, one must always call VP8ExitCritical() with the
 // same parameters. Both functions should be used in pair. Returns VP8_STATUS_OK
@@ -289,7 +291,7 @@ int VP8InitFrame(VP8Decoder* const dec, VP8Io* const io);
 VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io);
 // Must always be called in pair with VP8EnterCritical().
 // Returns false in case of error.
-int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io);
+WEBP_NODISCARD int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io);
 // Return the multi-threading method to use (0=off), depending
 // on options and bitstream size. Only for lossy decoding.
 int VP8GetThreadMethod(const WebPDecoderOptions* const options,
@@ -299,11 +301,12 @@ int VP8GetThreadMethod(const WebPDecoderOptions* const options,
 void VP8InitDithering(const WebPDecoderOptions* const options,
                       VP8Decoder* const dec);
 // Process the last decoded row (filtering + output).
-int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io);
+WEBP_NODISCARD int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io);
 // To be called at the start of a new scanline, to initialize predictors.
 void VP8InitScanline(VP8Decoder* const dec);
 // Decode one macroblock. Returns false if there is not enough data.
-int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br);
+WEBP_NODISCARD int VP8DecodeMB(VP8Decoder* const dec,
+                               VP8BitReader* const token_br);
 
 // in alpha.c
 const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,

src/dec/vp8l_dec.c

@@ -12,6 +12,7 @@
 // Authors: Vikas Arora (vikaas.arora@gmail.com)
 //          Jyrki Alakuijala (jyrki@google.com)
 
+#include <assert.h>
 #include <stdlib.h>
 
 #include "src/dec/alphai_dec.h"
@@ -19,10 +20,9 @@
 #include "src/dsp/dsp.h"
 #include "src/dsp/lossless.h"
 #include "src/dsp/lossless_common.h"
-#include "src/dsp/yuv.h"
-#include "src/utils/endian_inl_utils.h"
 #include "src/utils/huffman_utils.h"
 #include "src/utils/utils.h"
+#include "src/webp/format_constants.h"
 
 #define NUM_ARGB_CACHE_ROWS          16
 
@@ -101,6 +101,14 @@ static const uint16_t kTableSize[12] = {
   FIXED_TABLE_SIZE + 2704
 };
 
+static int VP8LSetError(VP8LDecoder* const dec, VP8StatusCode error) {
+  // The oldest error reported takes precedence over the new one.
+  if (dec->status_ == VP8_STATUS_OK || dec->status_ == VP8_STATUS_SUSPENDED) {
+    dec->status_ = error;
+  }
+  return 0;
+}
+
 static int DecodeImageStream(int xsize, int ysize,
                              int is_level0,
                              VP8LDecoder* const dec,
@@ -178,7 +186,7 @@ static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) {
 
 //------------------------------------------------------------------------------
 // Decodes the next Huffman code from bit-stream.
-// FillBitWindow(br) needs to be called at minimum every second call
+// VP8LFillBitWindow(br) needs to be called at minimum every second call
 // to ReadSymbol, in order to pre-fetch enough bits.
 static WEBP_INLINE int ReadSymbol(const HuffmanCode* table,
                                   VP8LBitReader* const br) {
@@ -253,11 +261,11 @@ static int ReadHuffmanCodeLengths(
   int symbol;
   int max_symbol;
   int prev_code_len = DEFAULT_CODE_LENGTH;
-  HuffmanCode table[1 << LENGTHS_TABLE_BITS];
+  HuffmanTables tables;
 
-  if (!VP8LBuildHuffmanTable(table, LENGTHS_TABLE_BITS,
-                             code_length_code_lengths,
-                             NUM_CODE_LENGTH_CODES)) {
+  if (!VP8LHuffmanTablesAllocate(1 << LENGTHS_TABLE_BITS, &tables) ||
+      !VP8LBuildHuffmanTable(&tables, LENGTHS_TABLE_BITS,
+                             code_length_code_lengths, NUM_CODE_LENGTH_CODES)) {
     goto End;
   }
 
@@ -277,7 +285,7 @@ static int ReadHuffmanCodeLengths(
     int code_len;
     if (max_symbol-- == 0) break;
     VP8LFillBitWindow(br);
-    p = &table[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK];
+    p = &tables.curr_segment->start[VP8LPrefetchBits(br) & LENGTHS_TABLE_MASK];
     VP8LSetBitPos(br, br->bit_pos_ + p->bits);
     code_len = p->value;
     if (code_len < kCodeLengthLiterals) {
@@ -300,14 +308,16 @@ static int ReadHuffmanCodeLengths(
   ok = 1;
 
  End:
-  if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+  VP8LHuffmanTablesDeallocate(&tables);
+  if (!ok) return VP8LSetError(dec, VP8_STATUS_BITSTREAM_ERROR);
   return ok;
 }
 
 // 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman
 // tree.
 static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
-                           int* const code_lengths, HuffmanCode* const table) {
+                           int* const code_lengths,
+                           HuffmanTables* const table) {
   int ok = 0;
   int size = 0;
   VP8LBitReader* const br = &dec->br_;
@@ -321,7 +331,7 @@ static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
     // The first code is either 1 bit or 8 bit code.
     int symbol = VP8LReadBits(br, (first_symbol_len_code == 0) ? 1 : 8);
     code_lengths[symbol] = 1;
-    // The second code (if present), is always 8 bit long.
+    // The second code (if present), is always 8 bits long.
     if (num_symbols == 2) {
       symbol = VP8LReadBits(br, 8);
       code_lengths[symbol] = 1;
@@ -331,10 +341,7 @@ static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
     int i;
     int code_length_code_lengths[NUM_CODE_LENGTH_CODES] = { 0 };
     const int num_codes = VP8LReadBits(br, 4) + 4;
-    if (num_codes > NUM_CODE_LENGTH_CODES) {
-      dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
-      return 0;
-    }
+    assert(num_codes <= NUM_CODE_LENGTH_CODES);
 
     for (i = 0; i < num_codes; ++i) {
       code_length_code_lengths[kCodeLengthCodeOrder[i]] = VP8LReadBits(br, 3);
@@ -349,36 +356,36 @@ static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
                                  code_lengths, alphabet_size);
   }
   if (!ok || size == 0) {
-    dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
-    return 0;
+    return VP8LSetError(dec, VP8_STATUS_BITSTREAM_ERROR);
   }
   return size;
 }
 
 static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
                             int color_cache_bits, int allow_recursion) {
-  int i, j;
+  int i;
   VP8LBitReader* const br = &dec->br_;
   VP8LMetadata* const hdr = &dec->hdr_;
   uint32_t* huffman_image = NULL;
   HTreeGroup* htree_groups = NULL;
-  HuffmanCode* huffman_tables = NULL;
-  HuffmanCode* huffman_table = NULL;
+  HuffmanTables* huffman_tables = &hdr->huffman_tables_;
   int num_htree_groups = 1;
   int num_htree_groups_max = 1;
-  int max_alphabet_size = 0;
-  int* code_lengths = NULL;
-  const int table_size = kTableSize[color_cache_bits];
   int* mapping = NULL;
   int ok = 0;
 
+  // Check the table has been 0 initialized (through InitMetadata).
+  assert(huffman_tables->root.start == NULL);
+  assert(huffman_tables->curr_segment == NULL);
+
   if (allow_recursion && VP8LReadBits(br, 1)) {
     // use meta Huffman codes.
-    const int huffman_precision = VP8LReadBits(br, 3) + 2;
+    const int huffman_precision =
+        MIN_HUFFMAN_BITS + VP8LReadBits(br, NUM_HUFFMAN_BITS);
     const int huffman_xsize = VP8LSubSampleSize(xsize, huffman_precision);
     const int huffman_ysize = VP8LSubSampleSize(ysize, huffman_precision);
     const int huffman_pixs = huffman_xsize * huffman_ysize;
-    if (!DecodeImageStream(huffman_xsize, huffman_ysize, 0, dec,
+    if (!DecodeImageStream(huffman_xsize, huffman_ysize, /*is_level0=*/0, dec,
                            &huffman_image)) {
       goto Error;
     }
@@ -402,7 +409,7 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
       // values [0, num_htree_groups)
       mapping = (int*)WebPSafeMalloc(num_htree_groups_max, sizeof(*mapping));
       if (mapping == NULL) {
-        dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+        VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
         goto Error;
       }
       // -1 means a value is unmapped, and therefore unused in the Huffman
@@ -421,29 +428,55 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
 
   if (br->eos_) goto Error;
 
-  // Find maximum alphabet size for the htree group.
-  for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
-    int alphabet_size = kAlphabetSize[j];
-    if (j == 0 && color_cache_bits > 0) {
-      alphabet_size += 1 << color_cache_bits;
-    }
-    if (max_alphabet_size < alphabet_size) {
-      max_alphabet_size = alphabet_size;
-    }
+  if (!ReadHuffmanCodesHelper(color_cache_bits, num_htree_groups,
+                              num_htree_groups_max, mapping, dec,
+                              huffman_tables, &htree_groups)) {
+    goto Error;
   }
+  ok = 1;
 
-  code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
-                                      sizeof(*code_lengths));
-  huffman_tables = (HuffmanCode*)WebPSafeMalloc(num_htree_groups * table_size,
-                                                sizeof(*huffman_tables));
-  htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
+  // All OK. Finalize pointers.
+  hdr->huffman_image_ = huffman_image;
+  hdr->num_htree_groups_ = num_htree_groups;
+  hdr->htree_groups_ = htree_groups;
 
-  if (htree_groups == NULL || code_lengths == NULL || huffman_tables == NULL) {
-    dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+ Error:
+  WebPSafeFree(mapping);
+  if (!ok) {
+    WebPSafeFree(huffman_image);
+    VP8LHuffmanTablesDeallocate(huffman_tables);
+    VP8LHtreeGroupsFree(htree_groups);
+  }
+  return ok;
+}
+
+int ReadHuffmanCodesHelper(int color_cache_bits, int num_htree_groups,
+                           int num_htree_groups_max, const int* const mapping,
+                           VP8LDecoder* const dec,
+                           HuffmanTables* const huffman_tables,
+                           HTreeGroup** const htree_groups) {
+  int i, j, ok = 0;
+  const int max_alphabet_size =
+      kAlphabetSize[0] + ((color_cache_bits > 0) ? 1 << color_cache_bits : 0);
+  const int table_size = kTableSize[color_cache_bits];
+  int* code_lengths = NULL;
+
+  if ((mapping == NULL && num_htree_groups != num_htree_groups_max) ||
+      num_htree_groups > num_htree_groups_max) {
+    goto Error;
+  }
+
+  code_lengths =
+      (int*)WebPSafeCalloc((uint64_t)max_alphabet_size, sizeof(*code_lengths));
+  *htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
+
+  if (*htree_groups == NULL || code_lengths == NULL ||
+      !VP8LHuffmanTablesAllocate(num_htree_groups * table_size,
+                                 huffman_tables)) {
+    VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
     goto Error;
   }
 
-  huffman_table = huffman_tables;
   for (i = 0; i < num_htree_groups_max; ++i) {
     // If the index "i" is unused in the Huffman image, just make sure the
     // coefficients are valid but do not store them.
@@ -460,7 +493,7 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
       }
     } else {
       HTreeGroup* const htree_group =
-          &htree_groups[(mapping == NULL) ? i : mapping[i]];
+          &(*htree_groups)[(mapping == NULL) ? i : mapping[i]];
       HuffmanCode** const htrees = htree_group->htrees;
       int size;
       int total_size = 0;
@@ -468,19 +501,20 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
       int max_bits = 0;
       for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
         int alphabet_size = kAlphabetSize[j];
-        htrees[j] = huffman_table;
         if (j == 0 && color_cache_bits > 0) {
           alphabet_size += (1 << color_cache_bits);
         }
-        size = ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_table);
+        size =
+            ReadHuffmanCode(alphabet_size, dec, code_lengths, huffman_tables);
+        htrees[j] = huffman_tables->curr_segment->curr_table;
         if (size == 0) {
           goto Error;
         }
         if (is_trivial_literal && kLiteralMap[j] == 1) {
-          is_trivial_literal = (huffman_table->bits == 0);
+          is_trivial_literal = (htrees[j]->bits == 0);
         }
-        total_size += huffman_table->bits;
-        huffman_table += size;
+        total_size += htrees[j]->bits;
+        huffman_tables->curr_segment->curr_table += size;
         if (j <= ALPHA) {
           int local_max_bits = code_lengths[0];
           int k;
@@ -511,19 +545,12 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
   }
   ok = 1;
 
-  // All OK. Finalize pointers.
-  hdr->huffman_image_ = huffman_image;
-  hdr->num_htree_groups_ = num_htree_groups;
-  hdr->htree_groups_ = htree_groups;
-  hdr->huffman_tables_ = huffman_tables;
-
  Error:
   WebPSafeFree(code_lengths);
-  WebPSafeFree(mapping);
   if (!ok) {
-    WebPSafeFree(huffman_image);
-    WebPSafeFree(huffman_tables);
-    VP8LHtreeGroupsFree(htree_groups);
+    VP8LHuffmanTablesDeallocate(huffman_tables);
+    VP8LHtreeGroupsFree(*htree_groups);
+    *htree_groups = NULL;
   }
   return ok;
 }
@@ -547,8 +574,7 @@ static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) {
                                scaled_data_size * sizeof(*scaled_data);
   uint8_t* memory = (uint8_t*)WebPSafeMalloc(memory_size, sizeof(*memory));
   if (memory == NULL) {
-    dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
-    return 0;
+    return VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
   }
   assert(dec->rescaler_memory == NULL);
   dec->rescaler_memory = memory;
@@ -1082,12 +1108,10 @@ static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
  End:
   br->eos_ = VP8LIsEndOfStream(br);
   if (!ok || (br->eos_ && pos < end)) {
-    ok = 0;
-    dec->status_ = br->eos_ ? VP8_STATUS_SUSPENDED
-                            : VP8_STATUS_BITSTREAM_ERROR;
-  } else {
-    dec->last_pixel_ = pos;
+    return VP8LSetError(
+        dec, br->eos_ ? VP8_STATUS_SUSPENDED : VP8_STATUS_BITSTREAM_ERROR);
   }
+  dec->last_pixel_ = pos;
   return ok;
 }
 
@@ -1237,9 +1261,20 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
   }
 
   br->eos_ = VP8LIsEndOfStream(br);
-  if (dec->incremental_ && br->eos_ && src < src_end) {
+  // In incremental decoding:
+  // br->eos_ && src < src_last: if 'br' reached the end of the buffer and
+  // 'src_last' has not been reached yet, there is not enough data. 'dec' has to
+  // be reset until there is more data.
+  // !br->eos_ && src < src_last: this cannot happen as either the buffer is
+  // fully read, either enough has been read to reach 'src_last'.
+  // src >= src_last: 'src_last' is reached, all is fine. 'src' can actually go
+  // beyond 'src_last' in case the image is cropped and an LZ77 goes further.
+  // The buffer might have been enough or there is some left. 'br->eos_' does
+  // not matter.
+  assert(!dec->incremental_ || (br->eos_ && src < src_last) || src >= src_last);
+  if (dec->incremental_ && br->eos_ && src < src_last) {
     RestoreState(dec);
-  } else if (!br->eos_) {
+  } else if ((dec->incremental_ && src >= src_last) || !br->eos_) {
     // Process the remaining rows corresponding to last row-block.
     if (process_func != NULL) {
       process_func(dec, row > last_row ? last_row : row);
@@ -1254,8 +1289,7 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
   return 1;
 
  Error:
-  dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
-  return 0;
+  return VP8LSetError(dec, VP8_STATUS_BITSTREAM_ERROR);
 }
 
 // -----------------------------------------------------------------------------
@@ -1281,7 +1315,7 @@ static int ExpandColorMap(int num_colors, VP8LTransform* const transform) {
     uint8_t* const new_data = (uint8_t*)new_color_map;
     new_color_map[0] = transform->data_[0];
     for (i = 4; i < 4 * num_colors; ++i) {
-      // Equivalent to AddPixelEq(), on a byte-basis.
+      // Equivalent to VP8LAddPixels(), on a byte-basis.
       new_data[i] = (data[i] + new_data[i - 4]) & 0xff;
     }
     for (; i < 4 * final_num_colors; ++i) {
@@ -1317,12 +1351,13 @@ static int ReadTransform(int* const xsize, int const* ysize,
   switch (type) {
     case PREDICTOR_TRANSFORM:
     case CROSS_COLOR_TRANSFORM:
-      transform->bits_ = VP8LReadBits(br, 3) + 2;
+      transform->bits_ =
+          MIN_TRANSFORM_BITS + VP8LReadBits(br, NUM_TRANSFORM_BITS);
       ok = DecodeImageStream(VP8LSubSampleSize(transform->xsize_,
                                                transform->bits_),
                              VP8LSubSampleSize(transform->ysize_,
                                                transform->bits_),
-                             0, dec, &transform->data_);
+                             /*is_level0=*/0, dec, &transform->data_);
       break;
     case COLOR_INDEXING_TRANSFORM: {
        const int num_colors = VP8LReadBits(br, 8) + 1;
@@ -1332,11 +1367,14 @@ static int ReadTransform(int* const xsize, int const* ysize,
                       : 3;
        *xsize = VP8LSubSampleSize(transform->xsize_, bits);
        transform->bits_ = bits;
-       ok = DecodeImageStream(num_colors, 1, 0, dec, &transform->data_);
-       ok = ok && ExpandColorMap(num_colors, transform);
+       ok = DecodeImageStream(num_colors, /*ysize=*/1, /*is_level0=*/0, dec,
+                              &transform->data_);
+       if (ok && !ExpandColorMap(num_colors, transform)) {
+         return VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
+       }
       break;
     }
-    case SUBTRACT_GREEN:
+    case SUBTRACT_GREEN_TRANSFORM:
       break;
     default:
       assert(0);    // can't happen
@@ -1358,7 +1396,7 @@ static void ClearMetadata(VP8LMetadata* const hdr) {
   assert(hdr != NULL);
 
   WebPSafeFree(hdr->huffman_image_);
-  WebPSafeFree(hdr->huffman_tables_);
+  VP8LHuffmanTablesDeallocate(&hdr->huffman_tables_);
   VP8LHtreeGroupsFree(hdr->htree_groups_);
   VP8LColorCacheClear(&hdr->color_cache_);
   VP8LColorCacheClear(&hdr->saved_color_cache_);
@@ -1379,7 +1417,9 @@ VP8LDecoder* VP8LNew(void) {
   return dec;
 }
 
-void VP8LClear(VP8LDecoder* const dec) {
+// Resets the decoder in its initial state, reclaiming memory.
+// Preserves the dec->status_ value.
+static void VP8LClear(VP8LDecoder* const dec) {
   int i;
   if (dec == NULL) return;
   ClearMetadata(&dec->hdr_);
@@ -1439,7 +1479,7 @@ static int DecodeImageStream(int xsize, int ysize,
     color_cache_bits = VP8LReadBits(br, 4);
     ok = (color_cache_bits >= 1 && color_cache_bits <= MAX_CACHE_BITS);
     if (!ok) {
-      dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+      VP8LSetError(dec, VP8_STATUS_BITSTREAM_ERROR);
       goto End;
     }
   }
@@ -1448,7 +1488,7 @@ static int DecodeImageStream(int xsize, int ysize,
   ok = ok && ReadHuffmanCodes(dec, transform_xsize, transform_ysize,
                               color_cache_bits, is_level0);
   if (!ok) {
-    dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+    VP8LSetError(dec, VP8_STATUS_BITSTREAM_ERROR);
     goto End;
   }
 
@@ -1456,8 +1496,7 @@ static int DecodeImageStream(int xsize, int ysize,
   if (color_cache_bits > 0) {
     hdr->color_cache_size_ = 1 << color_cache_bits;
     if (!VP8LColorCacheInit(&hdr->color_cache_, color_cache_bits)) {
-      dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
-      ok = 0;
+      ok = VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
       goto End;
     }
   } else {
@@ -1474,8 +1513,7 @@ static int DecodeImageStream(int xsize, int ysize,
     const uint64_t total_size = (uint64_t)transform_xsize * transform_ysize;
     data = (uint32_t*)WebPSafeMalloc(total_size, sizeof(*data));
     if (data == NULL) {
-      dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
-      ok = 0;
+      ok = VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
       goto End;
     }
   }
@@ -1520,8 +1558,7 @@ static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) {
   dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint32_t));
   if (dec->pixels_ == NULL) {
     dec->argb_cache_ = NULL;    // for soundness
-    dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
-    return 0;
+    return VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
   }
   dec->argb_cache_ = dec->pixels_ + num_pixels + cache_top_pixels;
   return 1;
@@ -1532,8 +1569,7 @@ static int AllocateInternalBuffers8b(VP8LDecoder* const dec) {
   dec->argb_cache_ = NULL;    // for soundness
   dec->pixels_ = (uint32_t*)WebPSafeMalloc(total_num_pixels, sizeof(uint8_t));
   if (dec->pixels_ == NULL) {
-    dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
-    return 0;
+    return VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
   }
   return 1;
 }
@@ -1588,7 +1624,8 @@ int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
   dec->status_ = VP8_STATUS_OK;
   VP8LInitBitReader(&dec->br_, data, data_size);
 
-  if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, 1, dec, NULL)) {
+  if (!DecodeImageStream(alph_dec->width_, alph_dec->height_, /*is_level0=*/1,
+                         dec, /*decoded_data=*/NULL)) {
     goto Err;
   }
 
@@ -1643,22 +1680,24 @@ int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) {
 
   if (dec == NULL) return 0;
   if (io == NULL) {
-    dec->status_ = VP8_STATUS_INVALID_PARAM;
-    return 0;
+    return VP8LSetError(dec, VP8_STATUS_INVALID_PARAM);
   }
 
   dec->io_ = io;
   dec->status_ = VP8_STATUS_OK;
   VP8LInitBitReader(&dec->br_, io->data, io->data_size);
   if (!ReadImageInfo(&dec->br_, &width, &height, &has_alpha)) {
-    dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
+    VP8LSetError(dec, VP8_STATUS_BITSTREAM_ERROR);
     goto Error;
   }
   dec->state_ = READ_DIM;
   io->width = width;
   io->height = height;
 
-  if (!DecodeImageStream(width, height, 1, dec, NULL)) goto Error;
+  if (!DecodeImageStream(width, height, /*is_level0=*/1, dec,
+                         /*decoded_data=*/NULL)) {
+    goto Error;
+  }
   return 1;
 
  Error:
@@ -1673,7 +1712,7 @@ int VP8LDecodeImage(VP8LDecoder* const dec) {
 
   if (dec == NULL) return 0;
 
-  assert(dec->hdr_.huffman_tables_ != NULL);
+  assert(dec->hdr_.huffman_tables_.root.start != NULL);
   assert(dec->hdr_.htree_groups_ != NULL);
   assert(dec->hdr_.num_htree_groups_ > 0);
 
@@ -1688,7 +1727,7 @@ int VP8LDecodeImage(VP8LDecoder* const dec) {
     assert(dec->output_ != NULL);
 
     if (!WebPIoInitFromOptions(params->options, io, MODE_BGRA)) {
-      dec->status_ = VP8_STATUS_INVALID_PARAM;
+      VP8LSetError(dec, VP8_STATUS_INVALID_PARAM);
       goto Err;
     }
 
@@ -1698,7 +1737,7 @@ int VP8LDecodeImage(VP8LDecoder* const dec) {
     if (io->use_scaling && !AllocateAndInitRescaler(dec, io)) goto Err;
 #else
     if (io->use_scaling) {
-      dec->status_ = VP8_STATUS_INVALID_PARAM;
+      VP8LSetError(dec, VP8_STATUS_INVALID_PARAM);
       goto Err;
     }
 #endif
@@ -1716,7 +1755,7 @@ int VP8LDecodeImage(VP8LDecoder* const dec) {
           dec->hdr_.saved_color_cache_.colors_ == NULL) {
         if (!VP8LColorCacheInit(&dec->hdr_.saved_color_cache_,
                                 dec->hdr_.color_cache_.hash_bits_)) {
-          dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+          VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
           goto Err;
         }
       }

src/dec/vp8li_dec.h

@@ -20,6 +20,7 @@
 #include "src/utils/bit_reader_utils.h"
 #include "src/utils/color_cache_utils.h"
 #include "src/utils/huffman_utils.h"
+#include "src/webp/types.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -51,7 +52,7 @@ typedef struct {
   uint32_t*       huffman_image_;
   int             num_htree_groups_;
   HTreeGroup*     htree_groups_;
-  HuffmanCode*    huffman_tables_;
+  HuffmanTables   huffman_tables_;
 } VP8LMetadata;
 
 typedef struct VP8LDecoder VP8LDecoder;
@@ -99,33 +100,42 @@ struct ALPHDecoder;  // Defined in dec/alphai.h.
 
 // Decodes image header for alpha data stored using lossless compression.
 // Returns false in case of error.
-int VP8LDecodeAlphaHeader(struct ALPHDecoder* const alph_dec,
-                          const uint8_t* const data, size_t data_size);
+WEBP_NODISCARD int VP8LDecodeAlphaHeader(struct ALPHDecoder* const alph_dec,
+                                         const uint8_t* const data,
+                                         size_t data_size);
 
 // Decodes *at least* 'last_row' rows of alpha. If some of the initial rows are
 // already decoded in previous call(s), it will resume decoding from where it
 // was paused.
 // Returns false in case of bitstream error.
-int VP8LDecodeAlphaImageStream(struct ALPHDecoder* const alph_dec,
-                               int last_row);
+WEBP_NODISCARD int VP8LDecodeAlphaImageStream(
+    struct ALPHDecoder* const alph_dec, int last_row);
 
 // Allocates and initialize a new lossless decoder instance.
-VP8LDecoder* VP8LNew(void);
+WEBP_NODISCARD VP8LDecoder* VP8LNew(void);
 
 // Decodes the image header. Returns false in case of error.
-int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io);
+WEBP_NODISCARD int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io);
 
 // Decodes an image. It's required to decode the lossless header before calling
 // this function. Returns false in case of error, with updated dec->status_.
-int VP8LDecodeImage(VP8LDecoder* const dec);
-
-// Resets the decoder in its initial state, reclaiming memory.
-// Preserves the dec->status_ value.
-void VP8LClear(VP8LDecoder* const dec);
+WEBP_NODISCARD int VP8LDecodeImage(VP8LDecoder* const dec);
 
 // Clears and deallocate a lossless decoder instance.
 void VP8LDelete(VP8LDecoder* const dec);
 
+// Helper function for reading the different Huffman codes and storing them in
+// 'huffman_tables' and 'htree_groups'.
+// If mapping is NULL 'num_htree_groups_max' must equal 'num_htree_groups'.
+// If it is not NULL, it maps 'num_htree_groups_max' indices to the
+// 'num_htree_groups' groups. If 'num_htree_groups_max' > 'num_htree_groups',
+// some of those indices map to -1. This is used for non-balanced codes to
+// limit memory usage.
+WEBP_NODISCARD int ReadHuffmanCodesHelper(
+    int color_cache_bits, int num_htree_groups, int num_htree_groups_max,
+    const int* const mapping, VP8LDecoder* const dec,
+    HuffmanTables* const huffman_tables, HTreeGroup** const htree_groups);
+
 //------------------------------------------------------------------------------
 
 #ifdef __cplusplus