Fix invalid incremental decoding check.

(cherry picked from commit 95ea5226c8)

Change-Id: I80c2165aa9fdf43077db155d2d00e0e99db73eab

.gitignore

@@ -31,3 +31,6 @@ src/webp/stamp-h1
 *.pdb
 /iosbuild
 /WebP.framework
+CMakeCache.txt
+CMakeFiles/
+cmake_install.cmake

.mailmap

@@ -8,3 +8,5 @@ Vikas Arora <vikasa@google.com>
 <slobodan.prijic@imgtec.com> <Slobodan.Prijic@imgtec.com>
 <vrabaud@google.com> <vincent.rabaud@gmail.com>
 Tamar Levy <tamar.levy@intel.com>
+<qrczak@google.com> <qrczak>
+Hui Su <huisu@google.com>

AUTHORS

@@ -2,6 +2,7 @@ Contributors:
 - Charles Munger (clm at google dot com)
 - Christian Duvivier (cduvivier at google dot com)
 - Djordje Pesut (djordje dot pesut at imgtec dot com)
+- Hui Su (huisu at google dot com)
 - James Zern (jzern at google dot com)
 - Jan Engelhardt (jengelh at medozas dot de)
 - Johann (johann dot koenig at duck dot com)
@@ -10,10 +11,13 @@ Contributors:
 - Lode Vandevenne (lode at google dot com)
 - Lou Quillio (louquillio at google dot com)
 - Mans Rullgard (mans at mansr dot com)
+- Marcin Kowalczyk (qrczak at google dot com)
 - Martin Olsson (mnemo at minimum dot se)
 - Mikołaj Zalewski (mikolajz at google dot com)
 - Mislav Bradac (mislavm at google dot com)
+- Nico Weber (thakis at chromium dot org)
 - Noel Chromium (noel at chromium dot org)
+- 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)
 - Pierre Joye (pierre dot php at gmail dot com)

Android.mk

@@ -1,6 +1,7 @@
 LOCAL_PATH := $(call my-dir)
 
 WEBP_CFLAGS := -Wall -DANDROID -DHAVE_MALLOC_H -DHAVE_PTHREAD -DWEBP_USE_THREAD
+WEBP_CFLAGS += -fvisibility=hidden
 
 ifeq ($(APP_OPTIM),release)
   WEBP_CFLAGS += -finline-functions -ffast-math \
@@ -49,6 +50,7 @@ dsp_dec_srcs := \
     src/dsp/dec_clip_tables.c \
     src/dsp/dec_mips32.c \
     src/dsp/dec_mips_dsp_r2.c \
+    src/dsp/dec_msa.c \
     src/dsp/dec_neon.$(NEON) \
     src/dsp/dec_sse2.c \
     src/dsp/dec_sse41.c \

CMakeLists.txt

@@ -0,0 +1,151 @@
+cmake_minimum_required(VERSION 2.8.7)
+
+project(libwebp C)
+
+# Options for coder / decoder executables.
+option(WEBP_BUILD_CWEBP "Build the cwebp command line tool." OFF)
+option(WEBP_BUILD_DWEBP "Build the dwebp command line tool." OFF)
+option(WEBP_EXPERIMENTAL_FEATURES "Build with experimental features." OFF)
+option(WEBP_FORCE_ALIGNED "Force aligned memory operations." OFF)
+option(WEBP_ENABLE_SWAP_16BIT_CSP "Enable byte swap for 16 bit colorspaces." OFF)
+
+set(WEBP_DEP_LIBRARIES)
+set(WEBP_DEP_INCLUDE_DIRS)
+
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE "Release" CACHE
+    "Build type: Release, Debug or RelWithDebInfo" STRING FORCE
+  )
+endif()
+
+include(cmake/config.h.cmake)
+
+################################################################################
+# Options.
+if(WEBP_ENABLE_SWAP_16BIT_CSP)
+  add_definitions(-DWEBP_SWAP_16BIT_CSP)
+endif()
+
+################################################################################
+# Android only.
+if(ANDROID)
+  include_directories(${ANDROID_NDK}/sources/android/cpufeatures)
+  add_library(cpufeatures STATIC
+    ${ANDROID_NDK}/sources/android/cpufeatures/cpu-features.c
+  )
+  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
+  )
+endif()
+
+################################################################################
+# WebP source files.
+# Read the Makefile.am to get the source files.
+set(WEBP_SRCS)
+
+function(parse_Makefile_am FOLDER WEBP_SRCS)
+  file(READ ${FOLDER}/Makefile.am MAKEFILE_AM)
+  string(REGEX MATCHALL "_SOURCES \\+= [^\n]*"
+    FILES_PER_LINE ${MAKEFILE_AM}
+  )
+  set(SRCS ${WEBP_SRCS})
+  foreach(FILES ${FILES_PER_LINE})
+    string(SUBSTRING ${FILES} 12 -1 FILES)
+    string(REGEX MATCHALL "[0-9a-z\\._]+"
+      FILES ${FILES}
+    )
+    foreach(FILE ${FILES})
+      list(APPEND SRCS ${FOLDER}/${FILE})
+    endforeach()
+  endforeach()
+  set(WEBP_SRCS ${SRCS} PARENT_SCOPE)
+endfunction()
+
+parse_Makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/dec "${WEBP_SRCS}")
+parse_Makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/demux "${WEBP_SRCS}")
+parse_Makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/dsp "${WEBP_SRCS}")
+parse_Makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/enc "${WEBP_SRCS}")
+parse_Makefile_am(${CMAKE_CURRENT_SOURCE_DIR}/src/utils "${WEBP_SRCS}")
+
+# Remove the files specific to SIMD we don't use.
+foreach(FILE ${WEBP_SIMD_FILES_NOT_TO_INCLUDE})
+  list(REMOVE_ITEM WEBP_SRCS ${FILE})
+endforeach()
+
+# Build the library.
+add_definitions(-Wall)
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/src/ ${WEBP_DEP_INCLUDE_DIRS})
+add_library(webp ${WEBP_SRCS})
+target_link_libraries(webp ${WEBP_DEP_LIBRARIES})
+
+# Change the compile flags for SIMD files we use.
+list(LENGTH WEBP_SIMD_FILES_TO_INCLUDE WEBP_SIMD_FILES_TO_INCLUDE_LENGTH)
+math(EXPR WEBP_SIMD_FILES_TO_INCLUDE_RANGE
+  "${WEBP_SIMD_FILES_TO_INCLUDE_LENGTH}-1"
+)
+
+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}
+  )
+endforeach()
+
+# Build the executables if asked for.
+if(WEBP_BUILD_CWEBP OR WEBP_BUILD_DWEBP)
+  # Example utility library.
+  set(exampleutil_SRCS
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/example_util.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/example_util.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h)
+  add_library(exampleutil ${exampleutil_SRCS})
+  target_link_libraries(exampleutil webp ${WEBP_DEP_LIBRARIES})
+endif()
+
+if(WEBP_BUILD_CWEBP)
+  # Image-decoding utility library.
+  set(exampledec_SRCS
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/image_dec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/image_dec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/jpegdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/jpegdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/metadata.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/metadata.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/pngdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/pngdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/tiffdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/tiffdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/webpdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/webpdec.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/wicdec.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/wicdec.h)
+  add_library(exampledec ${exampledec_SRCS})
+  target_link_libraries(exampledec webp ${WEBP_DEP_LIBRARIES}
+    ${WEBP_DEP_IMG_LIBRARIES})
+endif()
+
+if(WEBP_BUILD_DWEBP)
+  # dwebp
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+  add_executable(dwebp
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/dwebp.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h
+  )
+  target_link_libraries(dwebp webp exampleutil ${WEBP_DEP_LIBRARIES}
+    ${WEBP_DEP_IMG_LIBRARIES}
+  )
+endif()
+
+if(WEBP_BUILD_CWEBP)
+  # cwebp
+  include_directories(${WEBP_DEP_IMG_INCLUDE_DIRS})
+  add_executable(cwebp
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/cwebp.c
+    ${CMAKE_CURRENT_SOURCE_DIR}/examples/stopwatch.h)
+  target_link_libraries(cwebp exampledec webp exampleutil
+    ${WEBP_DEP_LIBRARIES} ${WEBP_DEP_IMG_LIBRARIES}
+  )
+endif()

ChangeLog

@@ -1,3 +1,233 @@
+aa7744c anim_util: quiet implicit conv warnings in 32-bit
+d912027 jpegdec: correct ContextFill signature
+24eb394 Remove some errors when compiling the code as C++.
+a4a8e5f vwebp: clear canvas during resize w/o animation
+31ca2a8 tiffdec: restore libtiff 3.9.x compatibility
+b2f77b5 update NEWS
+5ab6d9d AnimEncoder: avoid freeing uninitialized memory pointer.
+f29bf58 WebPAnimEncoder: If 'minimize_size' and 'allow_mixed' on, try lossy + lossless.
+df780e0 fix a potential overflow with MALLOC_LIMIT
+218460c bump version to 0.5.2
+de7d654 update AUTHORS & .mailmap
+74a12b1 iosbuild.sh: add WebPDecoder.framework + encoder
+be7dcc0 AnimEncoder: Correctly skip a frame when sub-rectangle is empty.
+4088583 Fix assertions in WebPRescalerExportRow()
+8f38c72 fix a typo in WebPPictureYUVAToARGB's doc
+33ca93f systematically call WebPDemuxReleaseIterator() on dec->prev_iter_
+76e1907 doc: use two's complement explicitly for uint8->int8 conversion
+f91ba96 Anim_encoder: correctly handle enc->prev_candidate_undecided_
+25d74e6 WebPPictureDistortion(): free() -> WebPSafeFree()
+03f1c00 mux/Makefile.am: add missing -lm
+58410cd fix bug in RefineUsingDistortion()
+e168af8 fix filtering auto-adjustment
+ed9dec4 fix doc and code snippet for WebPINewDecoder() doc
+3c49178 prevent 32b overflow for very large canvas_width / height
+9595f29 fix anim_util.c compilation when HAVE_GIF is not defined.
+7ec9552 Make gif transparent color to be transparent black
+9871335 Add a CMake option for WEBP_SWAP_16BIT_CSP.
+0ae3222 Fix missing cpu-features for Android.
+ab4c805 cpu.cmake: improve webp_check_compiler_flag output
+eec5fa3 Provide support for CMake on Android studio 2.2.
+004d569 Split the main CMake file.
+4fe5d58 Android.mk: use -fvisibility=hidden
+bd63a31 vwebp: ensure setenv() is available in stdlib.h
+363a568 vwebp: handle window resizing properly
+a0d2753 lower WEBP_MAX_ALLOCABLE_MEMORY default
+31fe11a  fix infinite loop in case of PARTITION0 overflow
+532215d Change the rule of picking UV mode in MBAnalyzeBestUVMode()
+9c75dbd cwebp.1: improve some grammar
+af2e05c vwebp: Clear previous frame when a key triggers a redraw
+26ffa29 Add descriptions of default configuration in help info.
+7416280 Fix an unsigned integer overflow error in enc/cost.h
+13cf1d2 Do token recording and counting in a single loop
+eb9a4b9 Reset segment id if we decide not to update segment map
+42ebe3b configure: fix NEON flag detection under gcc 6
+83cbfa0 Import: use relative pointer offsets
+a1ade40 PreprocessARGB: use relative pointer offsets
+fd4d090 ConvertWRGBToYUV: use relative pointer offsets
+9daad45 ImportYUVAFromRGBA: use relative pointer offsets
+c284780 imageio_util: add ImgIoUtilCheckSizeArgumentsOverflow
+e375080 gifdec,Remap: avoid out of bounds colormap read
+c222a05 additional fix for stride type as size_t
+bb23361 fix potential overflow when width * height * 4 >= (1<<32)
+883d41f gif2webp: fix crash with NULL extension data
+3d97bb7 update ChangeLog (tag: v0.5.1, origin/0.5.1, 0.5.1)
+deb54d9 Clarify the expected 'config' lifespan in WebPIDecode()
+c7e2d24 update ChangeLog (tag: v0.5.1-rc5)
+c7eb06f Fix corner case in CostManagerInit.
+ab7937a gif2webp: normalize the number of .'s in the help message
+3cdec84 vwebp: normalize the number of .'s in the help message
+bdf6241 cwebp: normalize the number of .'s in the help message
+06a38c7 fix rescaling bug: alpha plane wasn't filled with 0xff
+319e37b Improve lossless compression.
+447adbc 'our bug tracker' -> 'the bug tracker'
+97b9e64 normalize the number of .'s in the help message
+bb50bf4 pngdec,ReadFunc: throw an error on invalid read
+38063af decode.h,WebPGetInfo: normalize function comment
+9e8e1b7 Inline GetResidual for speed.
+7d58d1b Speed-up uniform-region processing.
+23e29cb Merge "Fix a boundary case in BackwardReferencesHashChainDistanceOnly." into 0.5.1
+0bb23b2 free -> WebPSafeFree()
+e7b9177 Merge "DecodeImageData(): change the incorrect assert" into 0.5.1
+2abfa54 DecodeImageData(): change the incorrect assert
+5a48fcd Merge "configure: test for -Wfloat-conversion"
+0174d18 Fix a boundary case in BackwardReferencesHashChainDistanceOnly.
+6a9c262 Merge "Added MSA optimized transform functions"
+cfbcc5e Make sure to consider small distances in LZ77.
+5e60c42 Added MSA optimized transform functions
+3dc28d7 configure: test for -Wfloat-conversion
+f2a0946 add some asserts to delimit the perimeter of CostManager's operation
+9a583c6 fix invalid-write bug for alpha-decoding
+f66512d make gradlew executable
+6fda58f backward_references: quiet double->int warning
+a48cc9d Merge "Fix a compression regression for images with long uniform regions." into 0.5.1
+cc2720c Merge "Revert an LZ77 boundary constant." into 0.5.1
+059aab4 Fix a compression regression for images with long uniform regions.
+b0c7e49 Check more backward matches with higher quality.
+a361151 Revert an LZ77 boundary constant.
+8190374 README: fix typo
+7551db4 update NEWS
+0fb2269 bump version to 0.5.1
+f453761 update AUTHORS & .mailmap
+3259571 Refactor GetColorPalette method.
+1df5e26 avoid using tmp histogram in PreparePair()
+7685123 fix comment typos
+a246b92 Speedup backward references.
+76d73f1 Merge "CostManager: introduce a free-list of ~10 intervals"
+eab39d8 CostManager: introduce a free-list of ~10 intervals
+4c59aac Merge "mips msa webp configuration"
+043c33f Merge "Improve speed and compression in backward reference for lossless."
+71be9b8 Merge "clarify variable names in HistogramRemap()"
+0ba7fd7 Improve speed and compression in backward reference for lossless.
+0481d42 CostManager: cache one interval and re-use it when possible
+41b7e6b Merge "histogram: fix bin calculation"
+96c3d62 histogram: fix bin calculation
+fe9e31e clarify variable names in HistogramRemap()
+ce3c824 disable near-lossless quantization if palette is used
+e11da08 mips msa webp configuration
+5f8f998 mux: Presence of unknown chunks should trigger VP8X chunk output.
+cadec0b Merge "Sync mips32 and dsp_r2 YUV->RGB code with C verison"
+d963775 Compute the hash chain once and for all for lossless compression.
+50a4866 Sync mips32 and dsp_r2 YUV->RGB code with C verison
+eee788e Merge "introduce a common signature for all image reader function"
+d77b877 introduce a common signature for all image reader function
+ca8d951 remove some obsolete TODOs
+ae2a722 collect all decoding utilities from examples/ in libexampledec.a
+0b8ae85 Merge "Move DitherCombine8x8 to dsp/dec.c"
+77cad88 Merge "ReadWebP: avoid conversion to ARGB if final format is YUVA"
+ab8d669 ReadWebP: avoid conversion to ARGB if final format is YUVA
+f8b7ce9 Merge "test pointer to NULL explicitly"
+5df6f21 test pointer to NULL explicitly
+77f21c9 Move DitherCombine8x8 to dsp/dec.c
+c9e6d86 Add gradle support
+c65f41e Revert "Add gradle support"
+bf731ed Add gradle support
+08333b8 WebPAnimEncoder: Detect when canvas is modified, restore only when needed.
+0209d7e Merge "speed-up MapToPalette() with binary search"
+fdd29a3 speed-up MapToPalette() with binary search
+cf4a651 Revert "Refactor GetColorPalette method."
+0a27aca Merge changes Idfa8ce83,I19adc9c4
+f25c440 WebPAnimEncoder: Restore original canvas between multiple encodes.
+169004b Refactor GetColorPalette method.
+576362a VP8LDoFillBitWindow: support big-endian in fast path
+ac49e4e bit_reader.c: s/VP8L_USE_UNALIGNED_LOAD/VP8L_USE_FAST_LOAD/
+d39ceb5 VP8LDoFillBitWindow: remove stale TODO
+2ec2de1 Merge "Speed-up BackwardReferencesHashChainDistanceOnly."
+3e023c1 Speed-up BackwardReferencesHashChainDistanceOnly.
+f2e1efb Improve near lossless compression when a prediction filter is used.
+e15afbc dsp.h: fix ubsan macro name
+e53c9cc dsp.h: add WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW
+af81fdb utils.h: quiet -fsanitize=undefined warnings
+ea0be35 dsp.h: remove utils.h include
+cd276ae utils/*.c: ../utils/utils.h -> ./utils.h
+c892713 utils/Makefile.am: add some missing headers
+ea24e02 Merge "dsp.h: add WEBP_UBSAN_IGNORE_UNDEF"
+369e264 dsp.h: add WEBP_UBSAN_IGNORE_UNDEF
+0d020a7 Merge "add runtime NEON detection"
+5ee2136 Merge "add VP8LAddPixels() to lossless.h"
+47435a6 add VP8LAddPixels() to lossless.h
+8fa6ac6 remove two ubsan warnings
+74fb56f add runtime NEON detection
+4154a83 MIPS update to new Unfilter API
+c80b9fc Merge "cherry-pick decoder fix for 64-bit android devices"
+6235147 cherry-pick decoder fix for 64-bit android devices
+d41b8c4 configure: test for -Wformat-* w/-Wformat present
+5f95589 Fix WEBP_ALIGN in case the argument is a pointer to a type larger than a byte.
+2309fd5 replace num_parts_ by num_parts_minus_one_ (unsigned)
+9629f4b SimplifySegments: quiet -Warray-bounds warning
+de47492 Merge "update the Unfilter API in dsp to process one row independently"
+2102ccd update the Unfilter API in dsp to process one row independently
+e3912d5 WebPAnimEncoder: Restore canvas before evaluating blending possibility.
+6e12e1e WebPAnimEncoder: Fix for single-frame optimization.
+602f344 Merge changes I1d03acac,Ifcb64219
+95ecccf only apply color-mapping for alpha on the cropped area
+47dd070 anim_diff: Add an experimental option for max inter-frame diff.
+aa809cf only allocate alpha_plane_ up to crop_bottom row
+31f2b8d WebPAnimEncoder: FlattenSimilarPixels(): look for similar
+774dfbd perform alpha filtering within the decoding loop
+a4cae68 lossless decoding: only process decoded row up to last_row
+238cdcd Only call WebPDequantizeLevels() on cropped area
+cf6c713 alpha: preparatory cleanup
+b95ac0a Merge "VP8GetHeaders(): initialize VP8Io with sane value for crop/scale dimensions"
+8923139 VP8GetHeaders(): initialize VP8Io with sane value for crop/scale dimensions
+5828e19 use_8b_decode -> use_8b_decode_
+8dca024 fix bug in alpha.c that was triggering a memory error in incremental mode
+9a950c5 WebPAnimEncoder: Disable filtering when blending is used with lossy encoding.
+eb42390 WebPAnimEncoder: choose max diff for framerect based on quality.
+ff0a94b WebPAnimEncoder lossy: ignore small pixel differences for frame rectangles.
+f804008 gif2webp: Remove the 'prev_to_prev_canvas' buffer.
+6d8c07d Merge "WebPDequantizeLevels(): use stride in CountLevels()"
+d96fe5e WebPDequantizeLevels(): use stride in CountLevels()
+ec1b240 WebPPictureImport*: check output pointer
+c076876 Merge "Revert "Re-enable encoding of alpha plane with color cache for next release.""
+41f14bc WebPPictureImport*: check src pointer
+64eed38 Pass stride parameter to WebPDequantizeLevels()
+97934e2 Revert "Re-enable encoding of alpha plane with color cache for next release."
+e88c4ca fix -m 2 mode-cost evaluation (causing partition0 overflow)
+4562e83 Merge "add extra meaning to WebPDecBuffer::is_external_memory"
+abdb109 add extra meaning to WebPDecBuffer::is_external_memory
+875aec7 enc_neon,cosmetics: break long comment
+71e856c GetMBSSIM,cosmetics: fix alignment
+a90edff fix missing 'extern' for SSIM function in dsp/
+423ecaf move some SSIM-accumulation function for dsp/
+f08e662 Merge "Fix FindClosestDiscretized in near lossless:"
+0d40cc5 enc_neon,Disto4x4: remove an unnecessary transpose
+e8feb20 Fix FindClosestDiscretized in near lossless:
+8200643 anim_util: quiet static analysis warning
+a6f23c4 Merge "AnimEncoder: Support progress hook and user data."
+a519377 Merge "Near lossless feature: fix some comments."
+da98d31 AnimEncoder: Support progress hook and user data.
+3335713 Near lossless feature: fix some comments.
+0beed01 cosmetics: fix indent after 2f5e898
+6753f35 Merge "FTransformWHT optimization."
+6583bb1 Improve SSE4.1 implementation of TTransform.
+7561d0c FTransformWHT optimization.
+7ccdb73 fix indentation after patch #328220
+6ec0d2a clarify the logic of the error path when decoding fails.
+8aa352b Merge "Remove an unnecessary transposition in TTransform."
+db86088 Merge "remove useless #include"
+9960c31 Remove an unnecessary transposition in TTransform.
+6e36b51 Small speedup in FTransform.
+9dbd4aa Merge "fix C and SIMD flags completion."
+e60853e Add missing common_sse2.h file to makefile.unix
+696eb2b fix C and SIMD flags completion.
+2b4fe33 Merge "fix multiple allocation for transform buffer"
+2f5e898 fix multiple allocation for transform buffer
+bf2b4f1 Regroup common SSE code + optimization.
+4ed650a force "-pass 6" if -psnr or -size is used but -pass isn't.
+3ef1ce9 yuv_sse2: fix -Wconstant-conversion warning
+a7a03e9 Merge changes I4852d18f,I51ccb85d
+5e122bd gif2webp: set enc_options.verbose = 0 w/-quiet
+ab3c258 anim_encode,DefaultEncoderOptions: init verbose
+8f0dee7 Merge "configure: fix builtin detection w/-Werror"
+4a7b85a cmake: fix builtin detection w/-Werror
+b74657f configure: fix builtin detection w/-Werror
+3661b98 Add a CMakeLists.txt
+75f4af4 remove useless #include
+6c1d763 avoid Yoda style for comparison
+8ce975a SSE optimization for vector mismatch.
+7db5383 Merge tag 'v0.5.0'
+37f0494 update ChangeLog (tag: v0.5.0-rc1, tag: v0.5.0, origin/0.5.0, 0.5.0)
 7e7b6cc faster rgb565/rgb4444/argb output
 4c7f565 update NEWS
 1f62b6b update AUTHORS
@@ -140,7 +370,7 @@ f7c507a Merge "remove unnecessary #include "yuv.h""
 7861578 for ReadXXXX() image-readers, use the value of pic->use_argb
 14e4043 remove unnecessary #include "yuv.h"
 469ba2c vwebp: fix incorrect clipping w/NO_BLEND
-4b9186b update issue tracker url (master)
+4b9186b update issue tracker url
 d64d376 change WEBP_ALIGN_CST value to 31
 f717b82 vp8l.c, cosmetics: fix indent after 95509f9
 927ccdc Merge "fix alignment of allocated memory in AllocateTransformBuffer"

Makefile.vc

@@ -194,6 +194,7 @@ DSP_DEC_OBJS = \
     $(DIROBJ)\dsp\dec_clip_tables.obj \
     $(DIROBJ)\dsp\dec_mips32.obj \
     $(DIROBJ)\dsp\dec_mips_dsp_r2.obj \
+    $(DIROBJ)\dsp\dec_msa.obj \
     $(DIROBJ)\dsp\dec_neon.obj \
     $(DIROBJ)\dsp\dec_sse2.obj \
     $(DIROBJ)\dsp\dec_sse41.obj \
@@ -244,6 +245,7 @@ EX_ANIM_UTIL_OBJS = \
     $(DIROBJ)\examples\anim_util.obj \
 
 EX_FORMAT_DEC_OBJS = \
+    $(DIROBJ)\examples\image_dec.obj \
     $(DIROBJ)\examples\jpegdec.obj \
     $(DIROBJ)\examples\metadata.obj \
     $(DIROBJ)\examples\pngdec.obj \

NEWS

@@ -1,3 +1,30 @@
+- 12/13/2016: version 0.5.2
+  This is a binary compatible release.
+  This release covers CVE-2016-8888 and CVE-2016-9085.
+  * further security related hardening in the tools; fixes to
+    gif2webp/AnimEncoder (issues #310, #314, #316, #322), cwebp/libwebp (issue
+    #312)
+  * full libwebp (encoder & decoder) iOS framework; libwebpdecoder
+    WebP.framework renamed to WebPDecoder.framework (issue #307)
+  * CMake support for Android Studio (2.2)
+  * miscellaneous build related fixes (issue #306, #313)
+  * miscellaneous documentation improvements (issue #225)
+  * minor lossy encoder fixes and improvements
+
+- 6/14/2016: version 0.5.1
+  This is a binary compatible release.
+  * miscellaneous bug fixes (issues #280, #289)
+  * reverted alpha plane encoding with color cache for compatibility with
+    libwebp 0.4.0->0.4.3 (issues #291, #298)
+  * lossless encoding performance improvements
+  * memory reduction in both lossless encoding and decoding
+  * force mux output to be in the extended format (VP8X) when undefined chunks
+    are present (issue #294)
+  * gradle, cmake build support
+  * workaround for compiler bug causing 64-bit decode failures on android
+    devices using clang-3.8 in the r11c NDK
+  * various WebPAnimEncoder improvements
+
 - 12/17/2015: version 0.5.0
   * miscellaneous bug & build fixes (issues #234, #258, #274, #275, #278)
   * encoder & decoder speed-ups on x86/ARM/MIPS for lossy & lossless

README

@@ -4,7 +4,7 @@
           \__\__/\____/\_____/__/ ____  ___
                 / _/ /    \    \ /  _ \/ _/
                /  \_/   / /   \ \   __/  \__
-               \____/____/\_____/_____/____/v0.5.0
+               \____/____/\_____/_____/____/v0.5.2
 
 Description:
 ============
@@ -20,7 +20,7 @@ https://chromium.googlesource.com/webm/libwebp
 
 It is released under the same license as the WebM project.
 See http://www.webmproject.org/license/software/ or the
-file "COPYING" file for details. An additional intellectual
+"COPYING" file for details. An additional intellectual
 property rights grant can be found in the file PATENTS.
 
 Building:
@@ -84,6 +84,73 @@ 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="$MIPS_LDFLAGS"
+make
+make install
+
+CMake:
+------
+The support for CMake is minimal: it only helps you compile libwebp, cwebp and
+dwebp.
+
+Prerequisites:
+A compiler (e.g., gcc with autotools) and CMake.
+On a Debian-like system the following should install everything you need for a
+minimal build:
+$ sudo apt-get install build-essential cmake
+
+When building from git sources, you will need to run cmake to generate the
+configure script.
+
+mkdir build && cd build && cmake ../
+make
+make install
+
+If you also want cwebp or dwebp, you will need to enable them through CMake:
+
+cmake -DWEBP_BUILD_CWEBP=ON -DWEBP_BUILD_DWEBP=ON ../
+
+or through your favorite interface (like ccmake or cmake-qt-gui).
+
+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:
 --------------
 
@@ -151,10 +218,11 @@ If input size (-s) for an image is not specified, it is
 assumed to be a PNG, JPEG, TIFF or WebP file.
 
 Options:
-  -h / -help  ............ short help
-  -H / -longhelp  ........ long help
-  -q <float> ............. quality factor (0:small..100:big)
-  -alpha_q <int> ......... transparency-compression quality (0..100)
+  -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
@@ -162,15 +230,15 @@ Options:
   -z <int> ............... activates lossless preset with given
                            level in [0:fast, ..., 9:slowest]
 
-  -m <int> ............... compression method (0=fast, 6=slowest)
-  -segments <int> ........ number of segments to use (1..4)
+  -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)
-  -f <int> ............... filter strength (0=off..100)
-  -sharpness <int> ....... filter sharpness (0:most .. 7:least sharp)
+  -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
   -partition_limit <int> . limit quality to fit the 512k limit on
@@ -185,18 +253,18 @@ Options:
   -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)
+  -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
+  -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
+  -lossless .............. encode image losslessly, default=off
   -near_lossless <int> ... use near-lossless image
-                           preprocessing (0..100=off)
+                           preprocessing (0..100=off), default=100
   -hint <string> ......... specify image characteristics hint,
                            one of: photo, picture or graph
 
@@ -274,7 +342,7 @@ Use following options to convert into alternate image formats:
   -yuv ......... save the raw YUV samples in flat layout
 
  Other options are:
-  -version  .... print version number and exit
+  -version ..... print version number and exit
   -nofancy ..... don't use the fancy YUV420 upscaler
   -nofilter .... disable in-loop filtering
   -nodither .... disable dithering
@@ -286,8 +354,8 @@ Use following options to convert into alternate image formats:
   -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)
+  -h ........... this help message
+  -v ........... verbose (e.g. print encoding/decoding times)
   -quiet ....... quiet mode, don't print anything
   -noasm ....... disable all assembly optimizations
 
@@ -303,7 +371,7 @@ Usage: vwebp in_file [options]
 
 Decodes the WebP image file and visualize it using OpenGL
 Options are:
-  -version  .... print version number and exit
+  -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
@@ -311,7 +379,7 @@ Options are:
   -noalphadither disable alpha plane dithering
   -mt .......... use multi-threading
   -info ........ print info
-  -h     ....... this help message
+  -h ........... this help message
 
 Keyboard shortcuts:
   'c' ................ toggle use of color profile
@@ -353,7 +421,7 @@ vwebp.
 Usage:
  gif2webp [options] gif_file -o webp_file
 Options:
-  -h / -help  ............ this help
+  -h / -help ............. this help
   -lossy ................. encode image using lossy compression
   -mixed ................. for each frame in the image, pick lossy
                            or lossless compression heuristically
@@ -637,7 +705,7 @@ an otherwise too-large picture. Some CPU can be saved too, incidentally.
 Bugs:
 =====
 
-Please report all bugs to our issue tracker:
+Please report all bugs to the issue tracker:
     https://bugs.chromium.org/p/webp
 Patches welcome! See this page to get started:
     http://www.webmproject.org/code/contribute/submitting-patches/

README.mux

@@ -1,7 +1,7 @@
           __   __  ____  ____  ____  __ __  _     __ __
          /  \\/  \/  _ \/  _ \/  _ \/  \  \/ \___/_ / _\
          \       /   __/  _  \   __/      /  /  (_/  /__
-          \__\__/\_____/_____/__/  \__//_/\_____/__/___/v0.3.0
+          \__\__/\_____/_____/__/  \__//_/\_____/__/___/v0.3.2
 
 
 Description:
@@ -198,7 +198,7 @@ For a detailed AnimEncoder API reference, please refer to the header file
 Bugs:
 =====
 
-Please report all bugs to our issue tracker:
+Please report all bugs to the issue tracker:
     https://bugs.chromium.org/p/webp
 Patches welcome! See this page to get started:
     http://www.webmproject.org/code/contribute/submitting-patches/

build.gradle

@@ -0,0 +1,337 @@
+// Define dependencies.
+buildscript {
+  repositories {
+    maven {
+      url "https://jcenter.bintray.com"
+    }
+  }
+  dependencies {
+    classpath "com.android.tools.build:gradle:${ANDROID_GRADLE_PLUGIN_VERSION}"
+  }
+}
+
+// Define versions in the project.
+project.ext {
+  buildToolsVersion = "${BUILD_TOOLS_VERSION}"
+  compileSdkVersion = COMPILE_SDK_VERSION.toInteger()
+}
+
+// Core libraries and executables.
+apply plugin: "c"
+def NEON
+model {
+  buildTypes {
+    debug
+    release
+  }
+  platforms {
+    arm {
+      architecture "arm"
+    }
+    arm64 {
+      architecture "arm64"
+    }
+    x86 {
+      architecture "x86"
+    }
+    x64 {
+      architecture "x86_64"
+    }
+    mips32r2
+    mips32r5
+    mips64r6
+  }
+  toolChains {
+    gcc(Gcc) {
+      target("mips32r2") {
+        cCompiler.args "-mips32r2"
+      }
+      target("mips32r5") {
+        cCompiler.args "-mips32r5"
+      }
+      target("mips64r6") {
+        cCompiler.args "-mips64r6"
+      }
+    }
+  }
+  binaries {
+    all {
+      if (toolChain in Gcc) {
+        cCompiler.args "-fPIC"
+        cCompiler.args "-Wall"
+        cCompiler.define "ANDROID"
+        cCompiler.define "HAVE_MALLOC_H"
+      }
+      // Optimizations.
+      if (buildType == buildTypes.release) {
+        if (toolChain in Gcc) {
+          cCompiler.args "-finline-functions"
+          cCompiler.args "-ffast-math"
+          cCompiler.args "-ffunction-sections"
+          cCompiler.args "-fdata-sections"
+        }
+        if (toolChain in Clang) {
+          cCompiler.args "-frename-registers -s"
+        }
+      }
+      // Check for NEON usage.
+      if (getTargetPlatform() == "arm" || getTargetPlatform() == "arm64") {
+        NEON = "c.neon"
+      } else {
+        NEON = "c"
+      }
+    }
+    // Link to pthread for shared libraries.
+    withType(SharedLibraryBinarySpec) {
+      if (toolChain in Gcc) {
+        cCompiler.define "HAVE_PTHREAD"
+        cCompiler.define "WEBP_USE_THREAD"
+        linker.args "-pthread"
+      }
+    }
+  }
+  components {
+    webp(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "src/dec"
+            include "alpha.c"
+            include "buffer.c"
+            include "frame.c"
+            include "idec.c"
+            include "io.c"
+            include "quant.c"
+            include "tree.c"
+            include "vp8.c"
+            include "vp8l.c"
+            include "webp.c"
+            srcDir "src/dsp"
+            include "alpha_processing.c"
+            include "alpha_processing_mips_dsp_r2.c"
+            include "alpha_processing_sse2.c"
+            include "alpha_processing_sse41.c"
+            include "argb.c"
+            include "argb_mips_dsp_r2.c"
+            include "argb_sse2.c"
+            include "cpu.c"
+            include "dec.c"
+            include "dec_clip_tables.c"
+            include "dec_mips32.c"
+            include "dec_mips_dsp_r2.c"
+            include "dec_msa.c"
+            include "dec_neon.$NEON"
+            include "dec_sse2.c"
+            include "dec_sse41.c"
+            include "filters.c"
+            include "filters_mips_dsp_r2.c"
+            include "filters_sse2.c"
+            include "lossless.c"
+            include "lossless_mips_dsp_r2.c"
+            include "lossless_neon.$NEON"
+            include "lossless_sse2.c"
+            include "rescaler.c"
+            include "rescaler_mips32.c"
+            include "rescaler_mips_dsp_r2.c"
+            include "rescaler_neon.$NEON"
+            include "rescaler_sse2.c"
+            include "upsampling.c"
+            include "upsampling_mips_dsp_r2.c"
+            include "upsampling_neon.$NEON"
+            include "upsampling_sse2.c"
+            include "yuv.c"
+            include "yuv_mips32.c"
+            include "yuv_mips_dsp_r2.c"
+            include "yuv_sse2.c"
+            srcDir "src/utils"
+            include "ans.c"
+            include "bit_reader.c"
+            include "color_cache.c"
+            include "filters.c"
+            include "huffman.c"
+            include "quant_levels_dec.c"
+            include "random.c"
+            include "rescaler.c"
+            include "thread.c"
+            include "utils.c"
+            srcDir "src/dsp"
+            include "cost.c"
+            include "cost_mips32.c"
+            include "cost_mips_dsp_r2.c"
+            include "cost_sse2.c"
+            include "enc.c"
+            include "enc_avx2.c"
+            include "enc_mips32.c"
+            include "enc_mips_dsp_r2.c"
+            include "enc_neon.$NEON"
+            include "enc_sse2.c"
+            include "enc_sse41.c"
+            include "lossless_enc.c"
+            include "lossless_enc_mips32.c"
+            include "lossless_enc_mips_dsp_r2.c"
+            include "lossless_enc_neon.$NEON"
+            include "lossless_enc_sse2.c"
+            include "lossless_enc_sse41.c"
+            srcDir "src/enc"
+            include "alpha.c"
+            include "analysis.c"
+            include "backward_references.c"
+            include "config.c"
+            include "cost.c"
+            include "delta_palettization.c"
+            include "filter.c"
+            include "frame.c"
+            include "histogram.c"
+            include "iterator.c"
+            include "near_lossless.c"
+            include "picture.c"
+            include "picture_csp.c"
+            include "picture_psnr.c"
+            include "picture_rescale.c"
+            include "picture_tools.c"
+            include "quant.c"
+            include "syntax.c"
+            include "token.c"
+            include "tree.c"
+            include "vp8l.c"
+            include "webpenc.c"
+            srcDir "src/utils"
+            include "bit_writer.c"
+            include "huffman_encode.c"
+            include "quant_levels.c"
+          }
+          exportedHeaders {
+            srcDir "src"
+          }
+        }
+      }
+    }
+
+    webpdemux(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "src/demux"
+            include "anim_decode.c"
+            include "demux.c"
+          }
+        }
+      }
+    }
+
+    webpmux(NativeLibrarySpec) {
+      sources {
+        c {
+          source {
+            srcDir "src/mux/"
+            include "anim_encode.c"
+            include "muxedit.c"
+            include "muxinternal.c"
+            include "muxread.c"
+          }
+        }
+      }
+    }
+
+    // Executables from examples.
+    example_util(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "example_util.c"
+          }
+        }
+      }
+    }
+
+    example_dec(NativeLibrarySpec) {
+      binaries {
+        all {
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "image_dec.c"
+            include "jpegdec.c"
+            include "metadata.c"
+            include "pngdec.c"
+            include "tiffdec.c"
+            include "webpdec.c"
+          }
+        }
+      }
+    }
+    cwebp(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "example_dec", linkage: "static"
+          lib library: "webp", linkage: "static"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "cwebp.c"
+          }
+        }
+      }
+    }
+
+    dwebp(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+              srcDir "./examples"
+              include "dwebp.c"
+          }
+        }
+      }
+    }
+
+    webpmux_example(NativeExecutableSpec) {
+      binaries {
+        all {
+          lib library: "example_util", linkage: "static"
+          lib library: "webpmux", linkage: "static"
+          lib library: "webp"
+        }
+      }
+      sources {
+        c {
+          source {
+            srcDir "./examples"
+            include "webpmux.c"
+          }
+        }
+      }
+    }
+  }
+  tasks {
+    // Task to test all possible configurations.
+    buildAllExecutables(Task) {
+      dependsOn $.binaries.findAll { it.buildable }
+    }
+  }
+}
+
+// Task to generate the wrapper.
+task wrapper(type: Wrapper) {
+  gradleVersion = '2.13'
+}

cmake/config.h.cmake

@@ -0,0 +1,141 @@
+# Generate the config.h to compile with specific intrinsics / libs.
+
+## Check for compiler options.
+include(CheckCSourceCompiles)
+check_c_source_compiles("
+    int main(void) {
+      (void)__builtin_bswap16(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP16
+)
+check_c_source_compiles("
+    int main(void) {
+      (void)__builtin_bswap32(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP32
+)
+check_c_source_compiles("
+    int main(void) {
+      (void)__builtin_bswap64(0);
+      return 0;
+    }
+  "
+  HAVE_BUILTIN_BSWAP64
+)
+
+## Check for libraries.
+find_package(Threads)
+if(Threads_FOUND)
+  if(CMAKE_USE_PTHREADS_INIT)
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")
+  endif()
+  foreach(PTHREAD_TEST HAVE_PTHREAD_PRIO_INHERIT PTHREAD_CREATE_UNDETACHED)
+    check_c_source_compiles("
+        #include <pthread.h>
+        int main (void) {
+          int attr = ${PTHREAD_TEST};
+          return attr;
+        }
+      " ${PTHREAD_TEST}
+    )
+  endforeach()
+  list(APPEND WEBP_DEP_LIBRARIES ${CMAKE_THREAD_LIBS_INIT})
+endif()
+set(WEBP_USE_THREAD ${Threads_FOUND})
+
+# TODO: this seems unused, check with autotools.
+set(LT_OBJDIR ".libs/")
+
+# Only useful for vwebp, so useless for now.
+# find_package(OpenGL)
+# set(WEBP_HAVE_GL ${OPENGL_FOUND})
+# set(WEBP_DEP_INCLUDE_DIRS ${WEBP_DEP_INCLUDE_DIRS} ${OPENGL_INCLUDE_DIRS})
+# set(WEBP_DEP_LIBRARIES ${WEBP_DEP_LIBRARIES} ${OPENGL_LIBRARIES})
+
+# Find the standard C math library.
+find_library(MATH_LIBRARY NAMES m)
+if(MATH_LIBRARY)
+  list(APPEND WEBP_DEP_LIBRARIES ${MATH_LIBRARY})
+endif()
+
+# Find the standard image libraries.
+set(WEBP_DEP_IMG_LIBRARIES)
+set(WEBP_DEP_IMG_INCLUDE_DIRS)
+foreach(I_LIB PNG JPEG TIFF GIF)
+  find_package(${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_DIRS})
+  endif()
+endforeach()
+
+## 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)
+endif()
+
+## Check for SIMD extensions.
+include(${CMAKE_CURRENT_LIST_DIR}/cpu.cmake)
+
+## Define extra info.
+set(PACKAGE ${PROJECT_NAME})
+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 ${CONFIGURE_AC}
+)
+function(strip_bracket VAR)
+  string(LENGTH ${${VAR}} TMP_LEN)
+  math(EXPR TMP_LEN ${TMP_LEN}-2)
+  string(SUBSTRING ${${VAR}} 1 ${TMP_LEN} TMP_SUB)
+  set(${VAR} ${TMP_SUB} PARENT_SCOPE)
+endfunction()
+
+list(GET CONFIGURE_AC_PACKAGE_INFO 1 PACKAGE_VERSION)
+strip_bracket(PACKAGE_VERSION)
+list(GET CONFIGURE_AC_PACKAGE_INFO 2 PACKAGE_BUGREPORT)
+strip_bracket(PACKAGE_BUGREPORT)
+list(GET CONFIGURE_AC_PACKAGE_INFO 3 PACKAGE_URL)
+strip_bracket(PACKAGE_URL)
+
+# Build more info.
+set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
+set(PACKAGE_TARNAME ${PACKAGE_NAME})
+set(VERSION ${PACKAGE_VERSION})
+
+## Generate the config.h header.
+configure_file(${CMAKE_CURRENT_LIST_DIR}/config.h.in
+  ${CMAKE_CURRENT_BINARY_DIR}/include/webp/config.h)
+add_definitions(-DHAVE_CONFIG_H)
+# The webp folder is included as we reference config.h as
+# ../webp/config.h or webp/config.h
+include_directories(${CMAKE_CURRENT_BINARY_DIR}/include
+  ${CMAKE_CURRENT_BINARY_DIR}/include/webp
+)

cmake/config.h.in

@@ -0,0 +1,146 @@
+/* Adapted from the autotools src/webp/config.h.in.  */
+
+/* Define if building universal (internal helper macro) */
+/* TODO: handle properly in CMake */
+#cmakedefine AC_APPLE_UNIVERSAL_BUILD 1
+
+/* Set to 1 if __builtin_bswap16 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP16 1
+
+/* Set to 1 if __builtin_bswap32 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP32 1
+
+/* Set to 1 if __builtin_bswap64 is available */
+#cmakedefine HAVE_BUILTIN_BSWAP64 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
+
+/* Define to 1 if you have the <wincodec.h> header file. */
+#cmakedefine HAVE_WINCODEC_H 1
+
+/* Define to 1 if you have the <windows.h> header file. */
+#cmakedefine HAVE_WINDOWS_H 1
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+/* TODO: handle properly in CMake */
+#cmakedefine LT_OBJDIR "@LT_OBJDIR@"
+
+/* Name of package */
+#cmakedefine PACKAGE "@PROJECT_NAME@"
+
+/* Define to the address where bug reports for this package should be sent. */
+#cmakedefine PACKAGE_BUGREPORT "@PACKAGE_BUGREPORT@"
+
+/* Define to the full name of this package. */
+#cmakedefine PACKAGE_NAME "@PACKAGE_NAME@"
+
+/* Define to the full name and version of this package. */
+#cmakedefine PACKAGE_STRING "@PACKAGE_STRING@"
+
+/* Define to the one symbol short name of this package. */
+#cmakedefine PACKAGE_TARNAME "@PACKAGE_TARNAME@"
+
+/* Define to the home page for this package. */
+#cmakedefine PACKAGE_URL "@PACKAGE_URL@"
+
+/* Define to the version of this package. */
+#cmakedefine PACKAGE_VERSION "@PACKAGE_VERSION@"
+
+/* Define to necessary symbol if this constant uses a non-standard name on
+   your system. */
+#cmakedefine PTHREAD_CREATE_JOINABLE 1
+
+/* Define to 1 if you have the ANSI C header files. */
+#cmakedefine STDC_HEADERS 1
+
+/* Version number of package */
+#cmakedefine VERSION "@VERSION@"
+
+/* Enable experimental code */
+#cmakedefine WEBP_EXPERIMENTAL_FEATURES 1
+
+/* Define to 1 to force aligned memory operations */
+#cmakedefine WEBP_FORCE_ALIGNED 1
+
+/* Set to 1 if AVX2 is supported */
+#cmakedefine WEBP_HAVE_AVX2 1
+
+/* Set to 1 if GIF library is installed */
+#cmakedefine WEBP_HAVE_GIF 1
+
+/* Set to 1 if OpenGL is supported */
+#cmakedefine WEBP_HAVE_GL 1
+
+/* Set to 1 if JPEG library is installed */
+#cmakedefine WEBP_HAVE_JPEG 1
+
+/* Set to 1 if PNG library is installed */
+#cmakedefine WEBP_HAVE_PNG 1
+
+/* Set to 1 if SSE2 is supported */
+#cmakedefine WEBP_HAVE_SSE2 1
+
+/* Set to 1 if SSE4.1 is supported */
+#cmakedefine WEBP_HAVE_SSE41 1
+
+/* Set to 1 if TIFF library is installed */
+#cmakedefine WEBP_HAVE_TIFF 1
+
+/* Undefine this to disable thread support. */
+#cmakedefine WEBP_USE_THREAD 1
+
+/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
+   significant byte first (like Motorola and SPARC, unlike Intel). */
+#if defined AC_APPLE_UNIVERSAL_BUILD
+# if defined __BIG_ENDIAN__
+#  define WORDS_BIGENDIAN 1
+# endif
+#else
+# ifndef WORDS_BIGENDIAN
+#  undef WORDS_BIGENDIAN
+# endif
+#endif

cmake/cpu.cmake

@@ -0,0 +1,96 @@
+## Check for SIMD extensions.
+
+function(webp_check_compiler_flag WEBP_SIMD_FLAG)
+  unset(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG} CACHE)
+  check_c_source_compiles("
+      #include \"${CMAKE_CURRENT_LIST_DIR}/../src/dsp/dsp.h\"
+      int main(void) {
+        #if !defined(WEBP_USE_${WEBP_SIMD_FLAG})
+        this is not valid code
+        #endif
+        return 0;
+      }
+    " WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG}
+  )
+  if(WEBP_HAVE_FLAG_${WEBP_SIMD_FLAG})
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 1 PARENT_SCOPE)
+  else()
+    set(WEBP_HAVE_${WEBP_SIMD_FLAG} 0 PARENT_SCOPE)
+  endif()
+endfunction()
+
+# those are included in the names of WEBP_USE_* in c++ code.
+set(WEBP_SIMD_FLAGS "SSE2;SSE41;AVX2;MIPS32;MIPS_DSP_R2;NEON;MSA")
+set(WEBP_SIMD_FILE_EXTENSIONS "_sse2.c;_sse41.c;_avx2.c;_mips32.c;_mips_dsp_r2.c;_neon.c;_msa.c")
+if(MSVC)
+  # MSVC does not have a SSE4 flag but AVX2 support implies
+  # SSE4 support.
+  set(SIMD_ENABLE_FLAGS "/arch:SSE2;/arch:AVX2;/arch:AVX2;;;;")
+  set(SIMD_DISABLE_FLAGS)
+else()
+  set(SIMD_ENABLE_FLAGS "-msse2;-msse4.1;-mavx2;-mips32;-mdspr2;-mfpu=neon;-mmsa")
+  set(SIMD_DISABLE_FLAGS "-mno-sse2;-mno-sse4.1;-mno-avx2;;-mno-dspr2;;-mno-msa")
+endif()
+
+set(WEBP_SIMD_FILES_TO_NOT_INCLUDE)
+set(WEBP_SIMD_FILES_TO_INCLUDE)
+set(WEBP_SIMD_FLAGS_TO_INCLUDE)
+
+if(${ANDROID})
+  if(${ANDROID_ABI} STREQUAL "armeabi-v7a")
+    # This is because Android studio uses the configuration
+    # "-march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16"
+    # that does not trigger neon optimizations but should
+    # (as this configuration does not exist anymore).
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mfpu=neon ")
+  endif()
+endif()
+
+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})
+  list(GET WEBP_SIMD_FLAGS ${I_SIMD} WEBP_SIMD_FLAG)
+
+  # First try with no extra flag added as the compiler might have default flags
+  # (especially on Android).
+  unset(WEBP_HAVE_${WEBP_SIMD_FLAG} CACHE)
+  set(CMAKE_REQUIRED_FLAGS)
+  webp_check_compiler_flag(${WEBP_SIMD_FLAG})
+  if(NOT WEBP_HAVE_${WEBP_SIMD_FLAG})
+    list(GET SIMD_ENABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+    set(CMAKE_REQUIRED_FLAGS ${SIMD_COMPILE_FLAG})
+    webp_check_compiler_flag(${WEBP_SIMD_FLAG})
+  else()
+    set(SIMD_COMPILE_FLAG " ")
+  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/*${WEBP_SIMD_FILE_EXTENSION}"
+  )
+  if(WEBP_HAVE_${WEBP_SIMD_FLAG})
+    # Memorize the file and flags.
+    foreach(FILE ${SIMD_FILES})
+      list(APPEND WEBP_SIMD_FILES_TO_INCLUDE ${FILE})
+      list(APPEND WEBP_SIMD_FLAGS_TO_INCLUDE ${SIMD_COMPILE_FLAG})
+    endforeach()
+  else()
+    # Remove the file from the list.
+    foreach(FILE ${SIMD_FILES})
+      list(APPEND WEBP_SIMD_FILES_NOT_TO_INCLUDE ${FILE})
+    endforeach()
+    # Explicitly disable SIMD.
+    if(SIMD_DISABLE_FLAGS)
+      list(GET SIMD_DISABLE_FLAGS ${I_SIMD} SIMD_COMPILE_FLAG)
+      include(CheckCCompilerFlag)
+      if(SIMD_COMPILE_FLAG)
+        unset(HAS_COMPILE_FLAG CACHE)
+        check_c_compiler_flag(${SIMD_COMPILE_FLAG} HAS_COMPILE_FLAG)
+        if(HAS_COMPILE_FLAG)
+          set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${SIMD_COMPILE_FLAG}")
+        endif()
+      endif()
+    endif()
+  endif()
+endforeach()

configure.ac

@@ -1,4 +1,4 @@
-AC_INIT([libwebp], [0.5.0],
+AC_INIT([libwebp], [0.5.2],
         [https://bugs.chromium.org/p/webp],,
         [http://developers.google.com/speed/webp])
 AC_CANONICAL_HOST
@@ -10,6 +10,7 @@ dnl === it must occur before LT_INIT (AC_PROG_LIBTOOL).
 m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
 
 AC_PROG_LIBTOOL
+AC_PROG_SED
 AM_PROG_CC_C_O
 
 dnl === Enable less verbose output when building.
@@ -68,8 +69,9 @@ TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-fvisibility=hidden])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wall])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wdeclaration-after-statement])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wextra])
-TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat-nonliteral])
-TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wformat-security])
+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])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wmissing-declarations])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wmissing-prototypes])
 TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wold-style-definition])
@@ -178,6 +180,71 @@ AS_IF([test "x$enable_sse2" != "xno"], [
     CFLAGS=$SAVED_CFLAGS])
   AC_SUBST([SSE2_FLAGS])])
 
+AC_ARG_ENABLE([neon],
+              AS_HELP_STRING([--disable-neon],
+                             [Disable detection of NEON support
+                              @<:@default=auto@:>@]))
+
+AC_ARG_ENABLE([neon_rtcd],
+              AS_HELP_STRING([--disable-neon-rtcd],
+                             [Disable runtime detection of NEON support via
+                              /proc/cpuinfo on Linux hosts
+                              @<:@default=auto@:>@]))
+# For ARM(7) hosts:
+# Both NEON flags unset and NEON support detected = build all modules with NEON
+# NEON detected with the use of -mfpu=neon = build only NEON modules with NEON
+AS_IF([test "x$enable_neon" != "xno"], [
+  case "$host_cpu" in
+    arm|armv7*)
+      # Test for NEON support without flags before falling back to -mfpu=neon
+      for flag in '' '-mfpu=neon'; do
+        LOCAL_NEON_FLAGS="$INTRINSICS_CFLAGS $NEON_FLAGS"
+        TEST_AND_ADD_CFLAGS([LOCAL_NEON_FLAGS], [$flag])
+        SAVED_CFLAGS=$CFLAGS
+        CFLAGS="$CFLAGS $LOCAL_NEON_FLAGS"
+
+        dnl Note AC_LANG_PROGRAM([]) uses an old-style main definition.
+        AC_COMPILE_IFELSE([AC_LANG_SOURCE([
+          #include <arm_neon.h>
+          int main(void) {
+            int8x8_t v = vdup_n_s8(0);
+            (void)v;
+            return 0;
+          }])],
+          [NEON_FLAGS="$(echo $LOCAL_NEON_FLAGS | $SED 's/^ *//')"
+           AS_IF([test -n "$NEON_FLAGS"], [
+             AS_IF([test "${host_os%%-*}" = "linux" -o \
+                         "x$enable_neon_rtcd" = "xno"], [
+               CFLAGS=$SAVED_CFLAGS
+               AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+               break
+             ],[
+               AC_MSG_WARN(m4_normalize([NEON runtime cpu-detection is
+                                         unavailable for ${host_os%%-*}. Force
+                                         with CFLAGS=-mfpu=neon or
+                                         --disable-neon-rtcd.]))
+               enable_neon_rtcd=no
+               NEON_FLAGS=""
+             ])
+           ],[
+             CFLAGS=$SAVED_CFLAGS
+             AC_DEFINE(WEBP_HAVE_NEON, [1], [Set to 1 if NEON is supported])
+             break
+           ])])
+        CFLAGS=$SAVED_CFLAGS
+      done
+
+      AS_IF([test -n "$NEON_FLAGS"], [
+        # If NEON is available and rtcd is disabled apply NEON_FLAGS globally.
+        AS_IF([test "x$enable_neon_rtcd" = "xno"], [
+          AM_CFLAGS="$AM_CFLAGS $NEON_FLAGS"
+          NEON_FLAGS=""],
+          [AC_DEFINE(WEBP_HAVE_NEON_RTCD, [1],
+                     [Set to 1 if runtime detection of NEON is enabled])])])
+        ;;
+    esac
+    AC_SUBST([NEON_FLAGS])])
+
 dnl === CLEAR_LIBVARS([var_pfx])
 dnl ===   Clears <var_pfx>_{INCLUDES,LIBS}.
 AC_DEFUN([CLEAR_LIBVARS], [$1_INCLUDES=""; $1_LIBS=""])
@@ -221,7 +288,7 @@ dnl ===   AC_DEFINE'ing <define> if successful.
 AC_DEFUN([CHECK_FOR_BUILTIN],
          [AC_LANG_PUSH([C])
           AC_MSG_CHECKING([for $1])
-          AC_LINK_IFELSE([AC_LANG_PROGRAM([], [$1($2)])],
+          AC_LINK_IFELSE([AC_LANG_PROGRAM([], [(void)$1($2)])],
                          [AC_MSG_RESULT([yes])
                           AC_DEFINE([$3], [1],
                                     [Set to 1 if $1 is available])],

doc/webp-lossless-bitstream-spec.txt

@@ -429,6 +429,11 @@ int8 ColorTransformDelta(int8 t, int8 c) {
 }
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+A conversion from the 8-bit unsigned representation (uint8) to the 8-bit
+signed one (int8) is required before calling ColorTransformDelta().
+It should be performed using 8-bit two's complement (that is: uint8 range
+\[128-255\] is mapped to the \[-128, -1\] range of its converted int8 value).
+
 The multiplication is to be done using more precision (with at least
 16-bit dynamics). The sign extension property of the shift operation
 does not matter here: only the lowest 8 bits are used from the result,

examples/Android.mk

@@ -15,6 +15,27 @@ LOCAL_MODULE := example_util
 
 include $(BUILD_STATIC_LIBRARY)
 
+
+################################################################################
+# libexample_dec
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    image_dec.c \
+    jpegdec.c \
+    metadata.c \
+    pngdec.c \
+    tiffdec.c \
+    webpdec.c \
+
+LOCAL_CFLAGS := $(WEBP_CFLAGS)
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
+
+LOCAL_MODULE := example_dec
+
+include $(BUILD_STATIC_LIBRARY)
+
 ################################################################################
 # cwebp
 
@@ -24,15 +45,10 @@ include $(CLEAR_VARS)
 # minor modification to their Android.mk files.
 LOCAL_SRC_FILES := \
     cwebp.c \
-    jpegdec.c \
-    metadata.c \
-    pngdec.c \
-    tiffdec.c \
-    webpdec.c \
 
 LOCAL_CFLAGS := $(WEBP_CFLAGS)
 LOCAL_C_INCLUDES := $(LOCAL_PATH)/../src
-LOCAL_STATIC_LIBRARIES := example_util webp
+LOCAL_STATIC_LIBRARIES := example_util example_dec webp
 
 LOCAL_MODULE := cwebp
 

examples/Makefile.am

@@ -12,16 +12,26 @@ if BUILD_GIF2WEBP
   bin_PROGRAMS += gif2webp
 endif
 
-noinst_LTLIBRARIES = libexampleutil.la
+noinst_LTLIBRARIES = libexampleutil.la libexampledec.la
 
 libexampleutil_la_SOURCES = example_util.c example_util.h stopwatch.h
 
+libexampledec_la_SOURCES  = image_dec.c image_dec.h
+libexampledec_la_SOURCES += jpegdec.c jpegdec.h
+libexampledec_la_SOURCES += metadata.c metadata.h
+libexampledec_la_SOURCES += pngdec.c pngdec.h
+libexampledec_la_SOURCES += tiffdec.c tiffdec.h
+libexampledec_la_SOURCES += webpdec.c webpdec.h
+libexampledec_la_SOURCES += wicdec.c wicdec.h
+libexampledec_la_CPPFLAGS = $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
+libexampledec_la_CPPFLAGS += $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
+
 if BUILD_ANIMDIFF
   noinst_PROGRAMS = anim_diff
 endif
 
 anim_diff_SOURCES = anim_diff.c anim_util.c anim_util.h
-anim_diff_CPPFLAGS = $(AM_CPPFLAGS) $(GIF_INCLUDES)
+anim_diff_CPPFLAGS = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE) $(GIF_INCLUDES)
 anim_diff_LDADD  = ../src/demux/libwebpdemux.la
 anim_diff_LDADD += libexampleutil.la
 anim_diff_LDADD += $(GIF_LIBS) -lm
@@ -31,15 +41,9 @@ dwebp_CPPFLAGS  = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
 dwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES)
 dwebp_LDADD = libexampleutil.la $(PNG_LIBS) $(JPEG_LIBS)
 
-cwebp_SOURCES  = cwebp.c metadata.c metadata.h stopwatch.h
-cwebp_SOURCES += jpegdec.c jpegdec.h
-cwebp_SOURCES += pngdec.c pngdec.h
-cwebp_SOURCES += tiffdec.c tiffdec.h
-cwebp_SOURCES += webpdec.c webpdec.h
-cwebp_SOURCES += wicdec.c wicdec.h
+cwebp_SOURCES  = cwebp.c stopwatch.h
 cwebp_CPPFLAGS  = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
-cwebp_CPPFLAGS += $(JPEG_INCLUDES) $(PNG_INCLUDES) $(TIFF_INCLUDES)
-cwebp_LDADD  = libexampleutil.la ../src/libwebp.la
+cwebp_LDADD  = libexampleutil.la libexampledec.la ../src/libwebp.la
 cwebp_LDADD += $(JPEG_LIBS) $(PNG_LIBS) $(TIFF_LIBS)
 
 gif2webp_SOURCES = gif2webp.c gifdec.c gifdec.h

examples/anim_diff.c

@@ -13,6 +13,7 @@
 //
 // example: anim_diff foo.gif bar.webp
 
+#include <assert.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>  // for 'strtod'.
@@ -29,20 +30,67 @@ static int AdditionWillOverflow(int a, int b) {
   return (b > 0) && (a > INT_MAX - b);
 }
 
-// Minimize number of frames by combining successive frames that have exact same
-// ARGB data into a single longer duration frame.
-static void MinimizeAnimationFrames(AnimatedImage* const img) {
+static int FramesAreEqual(const uint8_t* const rgba1,
+                          const uint8_t* const rgba2, int width, int height) {
+  const int stride = width * 4;  // Always true for 'DecodedFrame.rgba'.
+  return !memcmp(rgba1, rgba2, stride * height);
+}
+
+static WEBP_INLINE int PixelsAreSimilar(uint32_t src, uint32_t dst,
+                                        int max_allowed_diff) {
+  const int src_a = (src >> 24) & 0xff;
+  const int src_r = (src >> 16) & 0xff;
+  const int src_g = (src >> 8) & 0xff;
+  const int src_b = (src >> 0) & 0xff;
+  const int dst_a = (dst >> 24) & 0xff;
+  const int dst_r = (dst >> 16) & 0xff;
+  const int dst_g = (dst >> 8) & 0xff;
+  const int dst_b = (dst >> 0) & 0xff;
+
+  return (abs(src_r * src_a - dst_r * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_g * src_a - dst_g * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_b * src_a - dst_b * dst_a) <= (max_allowed_diff * 255)) &&
+         (abs(src_a - dst_a) <= max_allowed_diff);
+}
+
+static int FramesAreSimilar(const uint8_t* const rgba1,
+                            const uint8_t* const rgba2,
+                            int width, int height, int max_allowed_diff) {
+  int i, j;
+  assert(max_allowed_diff > 0);
+  for (j = 0; j < height; ++j) {
+    for (i = 0; i < width; ++i) {
+      const int stride = width * 4;
+      const size_t offset = j * stride + i;
+      if (!PixelsAreSimilar(rgba1[offset], rgba2[offset], max_allowed_diff)) {
+        return 0;
+      }
+    }
+  }
+  return 1;
+}
+
+// Minimize number of frames by combining successive frames that have at max
+// 'max_diff' difference per channel between corresponding pixels.
+static void MinimizeAnimationFrames(AnimatedImage* const img, int max_diff) {
   uint32_t i;
   for (i = 1; i < img->num_frames; ++i) {
     DecodedFrame* const frame1 = &img->frames[i - 1];
     DecodedFrame* const frame2 = &img->frames[i];
     const uint8_t* const rgba1 = frame1->rgba;
     const uint8_t* const rgba2 = frame2->rgba;
+    int should_merge_frames = 0;
     // If merging frames will result in integer overflow for 'duration',
     // skip merging.
     if (AdditionWillOverflow(frame1->duration, frame2->duration)) continue;
-    if (!memcmp(rgba1, rgba2, img->canvas_width * 4 * img->canvas_height)) {
-      // Merge 'i+1'th frame into 'i'th frame.
+    if (max_diff > 0) {
+      should_merge_frames = FramesAreSimilar(rgba1, rgba2, img->canvas_width,
+                                             img->canvas_height, max_diff);
+    } else {
+      should_merge_frames =
+          FramesAreEqual(rgba1, rgba2, img->canvas_width, img->canvas_height);
+    }
+    if (should_merge_frames) {  // Merge 'i+1'th frame into 'i'th frame.
       frame1->duration += frame2->duration;
       if (i + 1 < img->num_frames) {
         memmove(&img->frames[i], &img->frames[i + 1],
@@ -62,6 +110,20 @@ static int CompareValues(uint32_t a, uint32_t b, const char* output_str) {
   return 1;
 }
 
+static int CompareBackgroundColor(uint32_t bg1, uint32_t bg2, int premultiply) {
+  if (premultiply) {
+    const int alpha1 = (bg1 >> 24) & 0xff;
+    const int alpha2 = (bg2 >> 24) & 0xff;
+    if (alpha1 == 0 && alpha2 == 0) return 1;
+  }
+  if (bg1 != bg2) {
+    fprintf(stderr, "Background color mismatch: 0x%08x vs 0x%08x\n",
+            bg1, bg2);
+    return 0;
+  }
+  return 1;
+}
+
 // Note: As long as frame durations and reconstructed frames are identical, it
 // is OK for other aspects like offsets, dispose/blend method to vary.
 static int CompareAnimatedImagePair(const AnimatedImage* const img1,
@@ -83,8 +145,8 @@ static int CompareAnimatedImagePair(const AnimatedImage* const img1,
   if (is_multi_frame_image) {  // Checks relevant for multi-frame images only.
     ok = CompareValues(img1->loop_count, img2->loop_count,
                        "Loop count mismatch") && ok;
-    ok = CompareValues(img1->bgcolor, img2->bgcolor,
-                       "Background color mismatch") && ok;
+    ok = CompareBackgroundColor(img1->bgcolor, img2->bgcolor,
+                                premultiply) && ok;
   }
 
   for (i = 0; i < img1->num_frames; ++i) {
@@ -125,6 +187,11 @@ static void Help(void) {
   printf("  -min_psnr <float> ... minimum per-frame PSNR\n");
   printf("  -raw_comparison ..... if this flag is not used, RGB is\n");
   printf("                        premultiplied before comparison\n");
+#ifdef WEBP_EXPERIMENTAL_FEATURES
+  printf("  -max_diff <int> ..... maximum allowed difference per channel "
+         "                        between corresponding pixels in subsequent"
+         "                        frames\n");
+#endif
 }
 
 int main(int argc, const char* argv[]) {
@@ -135,6 +202,7 @@ int main(int argc, const char* argv[]) {
   int got_input1 = 0;
   int got_input2 = 0;
   int premultiply = 1;
+  int max_diff = 0;
   int i, c;
   const char* files[2] = { NULL, NULL };
   AnimatedImage images[2];
@@ -168,6 +236,21 @@ int main(int argc, const char* argv[]) {
       }
     } else if (!strcmp(argv[c], "-raw_comparison")) {
       premultiply = 0;
+#ifdef WEBP_EXPERIMENTAL_FEATURES
+    } else if (!strcmp(argv[c], "-max_diff")) {
+      if (c < argc - 1) {
+        const char* const v = argv[++c];
+        char* end = NULL;
+        const int n = (int)strtol(v, &end, 10);
+        if (end == v) {
+          parse_error = 1;
+          fprintf(stderr, "Error! '%s' is not an integer.\n", v);
+        }
+        max_diff = n;
+      } else {
+        parse_error = 1;
+      }
+#endif
     } else {
       if (!got_input1) {
         files[0] = argv[c];
@@ -201,7 +284,7 @@ int main(int argc, const char* argv[]) {
       return_code = -2;
       goto End;
     } else {
-      MinimizeAnimationFrames(&images[i]);
+      MinimizeAnimationFrames(&images[i], max_diff);
     }
   }
 

examples/anim_util.c

@@ -39,13 +39,24 @@ static int IsFullFrame(int width, int height,
   return (width == canvas_width && height == canvas_height);
 }
 
+static int CheckSizeForOverflow(uint64_t size) {
+  return (size == (size_t)size);
+}
+
 static int AllocateFrames(AnimatedImage* const image, uint32_t num_frames) {
   uint32_t i;
-  const size_t rgba_size =
-      image->canvas_width * kNumChannels * image->canvas_height;
-  uint8_t* const mem = (uint8_t*)malloc(num_frames * rgba_size * sizeof(*mem));
-  DecodedFrame* const frames =
-      (DecodedFrame*)malloc(num_frames * sizeof(*frames));
+  uint8_t* mem = NULL;
+  DecodedFrame* frames = NULL;
+  const uint64_t rgba_size =
+      (uint64_t)image->canvas_width * kNumChannels * image->canvas_height;
+  const uint64_t total_size = (uint64_t)num_frames * rgba_size * sizeof(*mem);
+  const uint64_t total_frame_size = (uint64_t)num_frames * sizeof(*frames);
+  if (!CheckSizeForOverflow(total_size) ||
+      !CheckSizeForOverflow(total_frame_size)) {
+    return 0;
+  }
+  mem = (uint8_t*)malloc((size_t)total_size);
+  frames = (DecodedFrame*)malloc((size_t)total_frame_size);
 
   if (mem == NULL || frames == NULL) {
     free(mem);
@@ -232,6 +243,7 @@ static int ReadAnimatedWebP(const char filename[],
       fprintf(stderr, "Error decoding frame #%u\n", frame_index);
       goto End;
     }
+    assert(frame_index < anim_info.frame_count);
     curr_frame = &image->frames[frame_index];
     curr_rgba = curr_frame->rgba;
     curr_frame->duration = timestamp - prev_frame_timestamp;
@@ -264,6 +276,8 @@ static int ReadAnimatedWebP(const char filename[],
 // -----------------------------------------------------------------------------
 // GIF Decoding.
 
+#ifdef WEBP_HAVE_GIF
+
 // Returns true if this is a valid GIF bitstream.
 static int IsGIF(const WebPData* const data) {
   return data->size > GIF_STAMP_LEN &&
@@ -272,8 +286,6 @@ static int IsGIF(const WebPData* const data) {
           !memcmp(GIF89_STAMP, data->bytes, GIF_STAMP_LEN));
 }
 
-#ifdef WEBP_HAVE_GIF
-
 // GIFLIB_MAJOR is only defined in libgif >= 4.2.0.
 #if defined(GIFLIB_MAJOR) && defined(GIFLIB_MINOR)
 # define LOCAL_GIF_VERSION ((GIFLIB_MAJOR << 8) | GIFLIB_MINOR)
@@ -395,7 +407,7 @@ static uint32_t GetBackgroundColorGIF(GifFileType* gif) {
   const ColorMapObject* const color_map = gif->SColorMap;
   if (transparent_index != NO_TRANSPARENT_COLOR &&
       gif->SBackGroundColor == transparent_index) {
-    return 0x00ffffff;  // Special case: transparent white.
+    return 0x00000000;  // Special case: transparent black.
   } else if (color_map == NULL || color_map->Colors == NULL
              || gif->SBackGroundColor >= color_map->ColorCount) {
     return 0xffffffff;  // Invalid: assume white.
@@ -664,6 +676,11 @@ static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
 
 #else
 
+static int IsGIF(const WebPData* const data) {
+  (void)data;
+  return 0;
+}
+
 static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
                            int dump_frames, const char dump_folder[]) {
   (void)filename;

examples/cwebp.c

@@ -20,17 +20,10 @@
 #include "webp/config.h"
 #endif
 
-#include "webp/encode.h"
-
 #include "./example_util.h"
-#include "./metadata.h"
+#include "./image_dec.h"
 #include "./stopwatch.h"
-
-#include "./jpegdec.h"
-#include "./pngdec.h"
-#include "./tiffdec.h"
-#include "./webpdec.h"
-#include "./wicdec.h"
+#include "webp/encode.h"
 
 #ifndef WEBP_DLL
 #ifdef __cplusplus
@@ -50,13 +43,12 @@ static int verbose = 0;
 
 static int ReadYUV(const uint8_t* const data, size_t data_size,
                    WebPPicture* const pic) {
-  int y;
   const int use_argb = pic->use_argb;
   const int uv_width = (pic->width + 1) / 2;
   const int uv_height = (pic->height + 1) / 2;
+  const int y_plane_size = pic->width * pic->height;
   const int uv_plane_size = uv_width * uv_height;
-  const size_t expected_data_size =
-      pic->width * pic->height + 2 * uv_plane_size;
+  const size_t expected_data_size = y_plane_size + 2 * uv_plane_size;
 
   if (data_size != expected_data_size) {
     fprintf(stderr,
@@ -67,18 +59,12 @@ static int ReadYUV(const uint8_t* const data, size_t data_size,
 
   pic->use_argb = 0;
   if (!WebPPictureAlloc(pic)) return 0;
-
-  for (y = 0; y < pic->height; ++y) {
-    memcpy(pic->y + y * pic->y_stride, data + y * pic->width,
-           pic->width * sizeof(*pic->y));
-  }
-  for (y = 0; y < uv_height; ++y) {
-    const uint8_t* const uv_data = data + pic->height * pic->y_stride;
-    memcpy(pic->u + y * pic->uv_stride, uv_data + y * uv_width,
-           uv_width * sizeof(*uv_data));
-    memcpy(pic->v + y * pic->uv_stride, uv_data + y * uv_width + uv_plane_size,
-           uv_width * sizeof(*uv_data));
-  }
+  ExUtilCopyPlane(data, pic->width, pic->y, pic->y_stride,
+                  pic->width, pic->height);
+  ExUtilCopyPlane(data + y_plane_size, uv_width,
+                  pic->u, pic->uv_stride, uv_width, uv_height);
+  ExUtilCopyPlane(data + y_plane_size + uv_plane_size, uv_width,
+                  pic->v, pic->uv_stride, uv_width, uv_height);
   return use_argb ? WebPPictureYUVAToARGB(pic) : 1;
 }
 
@@ -109,34 +95,6 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic,
 
 #else  // !HAVE_WINCODEC_H
 
-typedef enum {
-  PNG_ = 0,
-  JPEG_,
-  TIFF_,  // 'TIFF' clashes with libtiff
-  WEBP_,
-  UNSUPPORTED
-} InputFileFormat;
-
-static uint32_t GetBE32(const uint8_t buf[]) {
-  return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
-}
-
-static InputFileFormat GuessImageType(const uint8_t buf[12]) {
-  InputFileFormat format = UNSUPPORTED;
-  const uint32_t magic1 = GetBE32(buf + 0);
-  const uint32_t magic2 = GetBE32(buf + 8);
-  if (magic1 == 0x89504E47U) {
-    format = PNG_;
-  } else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
-    format = JPEG_;
-  } else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
-    format = TIFF_;
-  } else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
-    format = WEBP_;
-  }
-  return format;
-}
-
 static int ReadPicture(const char* const filename, WebPPicture* const pic,
                        int keep_alpha, Metadata* const metadata) {
   const uint8_t* data = NULL;
@@ -147,19 +105,8 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic,
   if (!ok) goto End;
 
   if (pic->width == 0 || pic->height == 0) {
-    ok = 0;
-    if (data_size >= 12) {
-      const InputFileFormat format = GuessImageType(data);
-      if (format == PNG_) {
-        ok = ReadPNG(data, data_size, pic, keep_alpha, metadata);
-      } else if (format == JPEG_) {
-        ok = ReadJPEG(data, data_size, pic, metadata);
-      } else if (format == TIFF_) {
-        ok = ReadTIFF(data, data_size, pic, keep_alpha, metadata);
-      } else if (format == WEBP_) {
-        ok = ReadWebP(data, data_size, pic, keep_alpha, metadata);
-      }
-    }
+    WebPImageReader reader = WebPGuessImageReader(data, data_size);
+    ok = (reader != NULL) && reader(data, data_size, pic, keep_alpha, metadata);
   } else {
     // If image size is specified, infer it as YUV format.
     ok = ReadYUV(data, data_size, pic);
@@ -567,11 +514,12 @@ static void HelpLong(void) {
   printf("Windows builds can take as input any of the files handled by WIC.\n");
 #endif
   printf("\nOptions:\n");
-  printf("  -h / -help  ............ short help\n");
-  printf("  -H / -longhelp  ........ long help\n");
-  printf("  -q <float> ............. quality factor (0:small..100:big)\n");
-  printf("  -alpha_q <int> ......... transparency-compression quality "
-         "(0..100)\n");
+  printf("  -h / -help ............. short help\n");
+  printf("  -H / -longhelp ......... long help\n");
+  printf("  -q <float> ............. quality factor (0:small..100:big), "
+         "default=75\n");
+  printf("  -alpha_q <int> ......... transparency-compression quality (0..100),"
+         "\n                           default=100\n");
   printf("  -preset <string> ....... preset setting, one of:\n");
   printf("                            default, photo, picture,\n");
   printf("                            drawing, icon, text\n");
@@ -579,16 +527,20 @@ static void HelpLong(void) {
   printf("  -z <int> ............... activates lossless preset with given\n"
          "                           level in [0:fast, ..., 9:slowest]\n");
   printf("\n");
-  printf("  -m <int> ............... compression method (0=fast, 6=slowest)\n");
-  printf("  -segments <int> ........ number of segments to use (1..4)\n");
+  printf("  -m <int> ............... compression method (0=fast, 6=slowest), "
+         "default=4\n");
+  printf("  -segments <int> ........ number of segments to use (1..4), "
+         "default=4\n");
   printf("  -size <int> ............ target size (in bytes)\n");
   printf("  -psnr <float> .......... target PSNR (in dB. typically: 42)\n");
   printf("\n");
   printf("  -s <int> <int> ......... input size (width x height) for YUV\n");
-  printf("  -sns <int> ............. spatial noise shaping (0:off, 100:max)\n");
-  printf("  -f <int> ............... filter strength (0=off..100)\n");
+  printf("  -sns <int> ............. spatial noise shaping (0:off, 100:max), "
+         "default=50\n");
+  printf("  -f <int> ............... filter strength (0=off..100), "
+         "default=60\n");
   printf("  -sharpness <int> ....... "
-         "filter sharpness (0:most .. 7:least sharp)\n");
+         "filter sharpness (0:most .. 7:least sharp), default=0\n");
   printf("  -strong ................ use strong filter instead "
                                      "of simple (default)\n");
   printf("  -nostrong .............. use simple filter instead of strong\n");
@@ -605,19 +557,21 @@ static void HelpLong(void) {
   printf("  -print_ssim ............ prints averaged SSIM distortion\n");
   printf("  -print_lsim ............ prints local-similarity distortion\n");
   printf("  -d <file.pgm> .......... dump the compressed output (PGM file)\n");
-  printf("  -alpha_method <int> .... transparency-compression method (0..1)\n");
+  printf("  -alpha_method <int> .... transparency-compression method (0..1), "
+         "default=1\n");
   printf("  -alpha_filter <string> . predictive filtering for alpha plane,\n");
   printf("                           one of: none, fast (default) or best\n");
-  printf("  -exact ................. preserve RGB values in transparent area"
-         "\n");
+  printf("  -exact ................. preserve RGB values in transparent area, "
+         "default=off\n");
   printf("  -blend_alpha <hex> ..... blend colors against background color\n"
          "                           expressed as RGB values written in\n"
          "                           hexadecimal, e.g. 0xc0e0d0 for red=0xc0\n"
          "                           green=0xe0 and blue=0xd0\n");
   printf("  -noalpha ............... discard any transparency information\n");
-  printf("  -lossless .............. encode image losslessly\n");
+  printf("  -lossless .............. encode image losslessly, default=off\n");
   printf("  -near_lossless <int> ... use near-lossless image\n"
-         "                           preprocessing (0..100=off)\n");
+         "                           preprocessing (0..100=off), "
+         "default=100\n");
 #ifdef WEBP_EXPERIMENTAL_FEATURES
   printf("  -delta_palettization ... use delta palettization\n");
 #endif  // WEBP_EXPERIMENTAL_FEATURES
@@ -972,6 +926,11 @@ int main(int argc, const char *argv[]) {
                       " encoding. Ignoring this option!\n");
     }
   }
+  // If a target size or PSNR was given, but somehow the -pass option was
+  // omitted, force a reasonable value.
+  if (config.target_size > 0 || config.target_PSNR > 0) {
+    if (config.pass == 1) config.pass = 6;
+  }
 
   if (!WebPValidateConfig(&config)) {
     fprintf(stderr, "Error! Invalid configuration.\n");

examples/dwebp.c

@@ -67,8 +67,13 @@ typedef enum {
   PGM,
   BMP,
   TIFF,
-  YUV,
-  ALPHA_PLANE_ONLY  // this is for experimenting only
+  RAW_YUV,
+  ALPHA_PLANE_ONLY,  // this is for experimenting only
+  // forced colorspace output (for testing, mostly)
+  RGB, RGBA, BGR, BGRA, ARGB,
+  RGBA_4444, RGB_565,
+  rgbA, bgrA, Argb, rgbA_4444,
+  YUV, YUVA
 } OutputFileFormat;
 
 #ifdef HAVE_WINCODEC_H
@@ -175,7 +180,7 @@ static int WritePNG(const char* out_file_name, int use_stdout,
   const uint32_t height = buffer->height;
   uint8_t* const rgb = buffer->u.RGBA.rgba;
   const int stride = buffer->u.RGBA.stride;
-  const int has_alpha = (buffer->colorspace == MODE_BGRA);
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
 
   return SUCCEEDED(WriteUsingWIC(out_file_name, use_stdout,
                                  MAKE_REFGUID(GUID_ContainerFormatPng),
@@ -193,7 +198,7 @@ static int WritePNG(FILE* out_file, const WebPDecBuffer* const buffer) {
   const uint32_t height = buffer->height;
   uint8_t* const rgb = buffer->u.RGBA.rgba;
   const int stride = buffer->u.RGBA.stride;
-  const int has_alpha = (buffer->colorspace == MODE_RGBA);
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
   volatile png_structp png;
   volatile png_infop info;
   png_uint_32 y;
@@ -259,6 +264,24 @@ static int WritePPM(FILE* fout, const WebPDecBuffer* const buffer, int alpha) {
   return 1;
 }
 
+// Save 16b mode (RGBA4444, RGB565, ...) for debugging purpose.
+static int Write16bAsPGM(FILE* fout, const WebPDecBuffer* const buffer) {
+  const uint32_t width = buffer->width;
+  const uint32_t height = buffer->height;
+  const uint8_t* const rgba = buffer->u.RGBA.rgba;
+  const int stride = buffer->u.RGBA.stride;
+  const uint32_t bytes_per_px = 2;
+  uint32_t y;
+
+  fprintf(fout, "P5\n%u %u\n255\n", width * bytes_per_px, height);
+  for (y = 0; y < height; ++y) {
+    if (fwrite(rgba + y * stride, width, bytes_per_px, fout) != bytes_per_px) {
+      return 0;
+    }
+  }
+  return 1;
+}
+
 static void PutLE16(uint8_t* const dst, uint32_t value) {
   dst[0] = (value >> 0) & 0xff;
   dst[1] = (value >> 8) & 0xff;
@@ -271,7 +294,7 @@ static void PutLE32(uint8_t* const dst, uint32_t value) {
 
 #define BMP_HEADER_SIZE 54
 static int WriteBMP(FILE* fout, const WebPDecBuffer* const buffer) {
-  const int has_alpha = (buffer->colorspace != MODE_BGR);
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
   const uint32_t width = buffer->width;
   const uint32_t height = buffer->height;
   const uint8_t* const rgba = buffer->u.RGBA.rgba;
@@ -332,7 +355,7 @@ static int WriteBMP(FILE* fout, const WebPDecBuffer* const buffer) {
 #define TIFF_HEADER_SIZE (EXTRA_DATA_OFFSET + EXTRA_DATA_SIZE)
 
 static int WriteTIFF(FILE* fout, const WebPDecBuffer* const buffer) {
-  const int has_alpha = (buffer->colorspace != MODE_RGB);
+  const int has_alpha = WebPIsAlphaMode(buffer->colorspace);
   const uint32_t width = buffer->width;
   const uint32_t height = buffer->height;
   const uint8_t* const rgba = buffer->u.RGBA.rgba;
@@ -418,7 +441,7 @@ static int WriteAlphaPlane(FILE* fout, const WebPDecBuffer* const buffer) {
 // format=PGM: save a grayscale PGM file using the IMC4 layout
 // (http://www.fourcc.org/yuv.php#IMC4). This is a very convenient format for
 // viewing the samples, esp. for odd dimensions.
-// format=YUV: just save the Y/U/V/A planes sequentially without header.
+// format=RAW_YUV: just save the Y/U/V/A planes sequentially without header.
 static int WritePGMOrYUV(FILE* fout, const WebPDecBuffer* const buffer,
                          OutputFileFormat format) {
   const int width = buffer->width;
@@ -426,7 +449,7 @@ static int WritePGMOrYUV(FILE* fout, const WebPDecBuffer* const buffer,
   const WebPYUVABuffer* const yuv = &buffer->u.YUVA;
   int ok = 1;
   int y;
-  const int pad = (format == YUV) ? 0 : 1;
+  const int pad = (format == RAW_YUV) ? 0 : 1;
   const int uv_width = (width + 1) / 2;
   const int uv_height = (height + 1) / 2;
   const int out_stride = (width + pad) & ~pad;
@@ -487,7 +510,9 @@ static int SaveOutput(const WebPDecBuffer* const buffer,
     }
   }
 
-  if (format == PNG) {
+  if (format == PNG ||
+      format == RGBA || format == BGRA || format == ARGB ||
+      format == rgbA || format == bgrA || format == Argb) {
 #ifdef HAVE_WINCODEC_H
     ok &= WritePNG(out_file, use_stdout, buffer);
 #else
@@ -495,14 +520,17 @@ static int SaveOutput(const WebPDecBuffer* const buffer,
 #endif
   } else if (format == PAM) {
     ok &= WritePPM(fout, buffer, 1);
-  } else if (format == PPM) {
+  } else if (format == PPM || format == RGB || format == BGR) {
     ok &= WritePPM(fout, buffer, 0);
+  } else if (format == RGBA_4444 || format == RGB_565 || format == rgbA_4444) {
+    ok &= Write16bAsPGM(fout, buffer);
   } else if (format == BMP) {
     ok &= WriteBMP(fout, buffer);
   } else if (format == TIFF) {
     ok &= WriteTIFF(fout, buffer);
-  } else if (format == PGM || format == YUV) {
-    ok &= WritePGMOrYUV(fout, buffer, format);
+  } else if (format == PGM || format == RAW_YUV ||
+             format == YUV || format == YUVA) {
+    ok &= WritePGMOrYUV(fout, buffer, format == RAW_YUV ? RAW_YUV : PGM);
   } else if (format == ALPHA_PLANE_ONLY) {
     ok &= WriteAlphaPlane(fout, buffer);
   }
@@ -544,7 +572,7 @@ static void Help(void) {
          "  -yuv ......... save the raw YUV samples in flat layout\n"
          "\n"
          " Other options are:\n"
-         "  -version  .... print version number and exit\n"
+         "  -version ..... print version number and exit\n"
          "  -nofancy ..... don't use the fancy YUV420 upscaler\n"
          "  -nofilter .... disable in-loop filtering\n"
          "  -nodither .... disable dithering\n"
@@ -556,8 +584,8 @@ static void Help(void) {
          "  -flip ........ flip the output vertically\n"
          "  -alpha ....... only save the alpha plane\n"
          "  -incremental . use incremental decoding (useful for tests)\n"
-         "  -h     ....... this help message\n"
-         "  -v     ....... verbose (e.g. print encoding/decoding times)\n"
+         "  -h ........... this help message\n"
+         "  -v ........... verbose (e.g. print encoding/decoding times)\n"
          "  -quiet ....... quiet mode, don't print anything\n"
 #ifndef WEBP_DLL
          "  -noasm ....... disable all assembly optimizations\n"
@@ -569,6 +597,70 @@ static const char* const kFormatType[] = {
   "unspecified", "lossy", "lossless"
 };
 
+static uint8_t* AllocateExternalBuffer(WebPDecoderConfig* config,
+                                       OutputFileFormat format,
+                                       int use_external_memory) {
+  uint8_t* external_buffer = NULL;
+  WebPDecBuffer* const output_buffer = &config->output;
+  int w = config->input.width;
+  int h = config->input.height;
+  if (config->options.use_scaling) {
+    w = config->options.scaled_width;
+    h = config->options.scaled_height;
+  } else if (config->options.use_cropping) {
+    w = config->options.crop_width;
+    h = config->options.crop_height;
+  }
+  if (format >= RGB && format <= rgbA_4444) {
+    const int bpp = (format == RGB || format == BGR) ? 3
+                  : (format == RGBA_4444 || format == rgbA_4444 ||
+                     format == RGB_565) ? 2
+                  : 4;
+    uint32_t stride = bpp * w + 7;   // <- just for exercising
+    external_buffer = (uint8_t*)malloc(stride * h);
+    if (external_buffer == NULL) return NULL;
+    output_buffer->u.RGBA.stride = stride;
+    output_buffer->u.RGBA.size = stride * h;
+    output_buffer->u.RGBA.rgba = external_buffer;
+  } else {    // YUV and YUVA
+    const int has_alpha = WebPIsAlphaMode(output_buffer->colorspace);
+    uint8_t* tmp;
+    uint32_t stride = w + 3;
+    uint32_t uv_stride = (w + 1) / 2 + 13;
+    uint32_t total_size = stride * h * (has_alpha ? 2 : 1)
+                        + 2 * uv_stride * (h + 1) / 2;
+    assert(format >= YUV && format <= YUVA);
+    external_buffer = (uint8_t*)malloc(total_size);
+    if (external_buffer == NULL) return NULL;
+    tmp = external_buffer;
+    output_buffer->u.YUVA.y = tmp;
+    output_buffer->u.YUVA.y_stride = stride;
+    output_buffer->u.YUVA.y_size = stride * h;
+    tmp += output_buffer->u.YUVA.y_size;
+    if (has_alpha) {
+      output_buffer->u.YUVA.a = tmp;
+      output_buffer->u.YUVA.a_stride = stride;
+      output_buffer->u.YUVA.a_size = stride * h;
+      tmp += output_buffer->u.YUVA.a_size;
+    } else {
+      output_buffer->u.YUVA.a = NULL;
+      output_buffer->u.YUVA.a_stride = 0;
+    }
+    output_buffer->u.YUVA.u = tmp;
+    output_buffer->u.YUVA.u_stride = uv_stride;
+    output_buffer->u.YUVA.u_size = uv_stride * (h + 1) / 2;
+    tmp += output_buffer->u.YUVA.u_size;
+
+    output_buffer->u.YUVA.v = tmp;
+    output_buffer->u.YUVA.v_stride = uv_stride;
+    output_buffer->u.YUVA.v_size = uv_stride * (h + 1) / 2;
+    tmp += output_buffer->u.YUVA.v_size;
+    assert(tmp <= external_buffer + total_size);
+  }
+  output_buffer->is_external_memory = use_external_memory;
+  return external_buffer;
+}
+
 int main(int argc, const char *argv[]) {
   int ok = 0;
   const char *in_file = NULL;
@@ -578,6 +670,10 @@ int main(int argc, const char *argv[]) {
   WebPDecBuffer* const output_buffer = &config.output;
   WebPBitstreamFeatures* const bitstream = &config.input;
   OutputFileFormat format = PNG;
+  uint8_t* external_buffer = NULL;
+  int use_external_memory = 0;
+  const uint8_t* data = NULL;
+
   int incremental = 0;
   int c;
 
@@ -617,7 +713,32 @@ int main(int argc, const char *argv[]) {
     } else if (!strcmp(argv[c], "-pgm")) {
       format = PGM;
     } else if (!strcmp(argv[c], "-yuv")) {
-      format = YUV;
+      format = RAW_YUV;
+    } else if (!strcmp(argv[c], "-pixel_format") && c < argc - 1) {
+      const char* const fmt = argv[++c];
+      if      (!strcmp(fmt, "RGB"))  format = RGB;
+      else if (!strcmp(fmt, "RGBA")) format = RGBA;
+      else if (!strcmp(fmt, "BGR"))  format = BGR;
+      else if (!strcmp(fmt, "BGRA")) format = BGRA;
+      else if (!strcmp(fmt, "ARGB")) format = ARGB;
+      else if (!strcmp(fmt, "RGBA_4444")) format = RGBA_4444;
+      else if (!strcmp(fmt, "RGB_565")) format = RGB_565;
+      else if (!strcmp(fmt, "rgbA")) format = rgbA;
+      else if (!strcmp(fmt, "bgrA")) format = bgrA;
+      else if (!strcmp(fmt, "Argb")) format = Argb;
+      else if (!strcmp(fmt, "rgbA_4444")) format = rgbA_4444;
+      else if (!strcmp(fmt, "YUV"))  format = YUV;
+      else if (!strcmp(fmt, "YUVA")) format = YUVA;
+      else {
+        fprintf(stderr, "Can't parse pixel_format %s\n", fmt);
+        parse_error = 1;
+      }
+    } else if (!strcmp(argv[c], "-external_memory") && c < argc - 1) {
+      use_external_memory = ExUtilGetInt(argv[++c], 0, &parse_error);
+      parse_error |= (use_external_memory > 2 || use_external_memory < 0);
+      if (parse_error) {
+        fprintf(stderr, "Can't parse 'external_memory' value %s\n", argv[c]);
+      }
     } else if (!strcmp(argv[c], "-mt")) {
       config.options.use_threads = 1;
     } else if (!strcmp(argv[c], "-alpha_dither")) {
@@ -676,7 +797,6 @@ int main(int argc, const char *argv[]) {
   {
     VP8StatusCode status = VP8_STATUS_OK;
     size_t data_size = 0;
-    const uint8_t* data = NULL;
     if (!ExUtilLoadWebP(in_file, &data, &data_size, bitstream)) {
       return -1;
     }
@@ -703,15 +823,33 @@ int main(int argc, const char *argv[]) {
             bitstream->has_alpha ? MODE_rgbA : MODE_RGB;
         break;
       case PGM:
-      case YUV:
+      case RAW_YUV:
         output_buffer->colorspace = bitstream->has_alpha ? MODE_YUVA : MODE_YUV;
         break;
       case ALPHA_PLANE_ONLY:
         output_buffer->colorspace = MODE_YUVA;
         break;
-      default:
-        free((void*)data);
-        return -1;
+      // forced modes:
+      case RGB: output_buffer->colorspace = MODE_RGB; break;
+      case RGBA: output_buffer->colorspace = MODE_RGBA; break;
+      case BGR: output_buffer->colorspace = MODE_BGR; break;
+      case BGRA: output_buffer->colorspace = MODE_BGRA; break;
+      case ARGB: output_buffer->colorspace = MODE_ARGB; break;
+      case RGBA_4444: output_buffer->colorspace = MODE_RGBA_4444; break;
+      case RGB_565: output_buffer->colorspace = MODE_RGB_565; break;
+      case rgbA: output_buffer->colorspace = MODE_rgbA; break;
+      case bgrA: output_buffer->colorspace = MODE_bgrA; break;
+      case Argb: output_buffer->colorspace = MODE_Argb; break;
+      case rgbA_4444: output_buffer->colorspace = MODE_rgbA_4444; break;
+      case YUV: output_buffer->colorspace = MODE_YUV; break;
+      case YUVA: output_buffer->colorspace = MODE_YUVA; break;
+      default: goto Exit;
+    }
+
+    if (use_external_memory > 0 && format >= RGB) {
+      external_buffer = AllocateExternalBuffer(&config, format,
+                                               use_external_memory);
+      if (external_buffer == NULL) goto Exit;
     }
 
     if (incremental) {
@@ -720,7 +858,6 @@ int main(int argc, const char *argv[]) {
       status = ExUtilDecodeWebP(data, data_size, verbose, &config);
     }
 
-    free((void*)data);
     ok = (status == VP8_STATUS_OK);
     if (!ok) {
       ExUtilPrintWebPError(in_file, status);
@@ -750,6 +887,8 @@ int main(int argc, const char *argv[]) {
   }
  Exit:
   WebPFreeDecBuffer(output_buffer);
+  free((void*)external_buffer);
+  free((void*)data);
   return ok ? 0 : -1;
 }
 

examples/example_util.c

@@ -268,3 +268,21 @@ VP8StatusCode ExUtilDecodeWebPIncremental(
 }
 
 // -----------------------------------------------------------------------------
+
+void ExUtilCopyPlane(const uint8_t* src, int src_stride,
+                     uint8_t* dst, int dst_stride, int width, int height) {
+  while (height-- > 0) {
+    memcpy(dst, src, width * sizeof(*dst));
+    src += src_stride;
+    dst += dst_stride;
+  }
+}
+
+// -----------------------------------------------------------------------------
+
+int ImgIoUtilCheckSizeArgumentsOverflow(uint64_t nmemb, size_t size) {
+  const uint64_t total_size = nmemb * size;
+  return (total_size == (size_t)total_size);
+}
+
+// -----------------------------------------------------------------------------

examples/example_util.h

@@ -53,6 +53,17 @@ int ExUtilReadFromStdin(const uint8_t** data, size_t* data_size);
 int ExUtilWriteFile(const char* const file_name,
                     const uint8_t* data, size_t data_size);
 
+//------------------------------------------------------------------------------
+
+// Copy width x height pixels from 'src' to 'dst' honoring the strides.
+void ExUtilCopyPlane(const uint8_t* src, int src_stride,
+                     uint8_t* dst, int dst_stride, int width, int height);
+
+//------------------------------------------------------------------------------
+
+// Returns 0 in case of overflow of nmemb * size.
+int ImgIoUtilCheckSizeArgumentsOverflow(uint64_t nmemb, size_t size);
+
 //------------------------------------------------------------------------------
 // WebP decoding
 

examples/gif2webp.c

@@ -55,7 +55,7 @@ static void Help(void) {
   printf("Usage:\n");
   printf(" gif2webp [options] gif_file -o webp_file\n");
   printf("Options:\n");
-  printf("  -h / -help  ............ this help\n");
+  printf("  -h / -help ............. this help\n");
   printf("  -lossy ................. encode image using lossy compression\n");
   printf("  -mixed ................. for each frame in the image, pick lossy\n"
          "                           or lossless compression heuristically\n");
@@ -98,7 +98,6 @@ int main(int argc, const char *argv[]) {
   WebPPicture frame;                // Frame rectangle only (not disposed).
   WebPPicture curr_canvas;          // Not disposed.
   WebPPicture prev_canvas;          // Disposed.
-  WebPPicture prev_to_prev_canvas;  // Disposed.
 
   WebPAnimEncoder* enc = NULL;
   WebPAnimEncoderOptions enc_options;
@@ -124,8 +123,7 @@ int main(int argc, const char *argv[]) {
 
   if (!WebPConfigInit(&config) || !WebPAnimEncoderOptionsInit(&enc_options) ||
       !WebPPictureInit(&frame) || !WebPPictureInit(&curr_canvas) ||
-      !WebPPictureInit(&prev_canvas) ||
-      !WebPPictureInit(&prev_to_prev_canvas)) {
+      !WebPPictureInit(&prev_canvas)) {
     fprintf(stderr, "Error! Version mismatch!\n");
     return -1;
   }
@@ -217,6 +215,7 @@ int main(int argc, const char *argv[]) {
       return 0;
     } else if (!strcmp(argv[c], "-quiet")) {
       quiet = 1;
+      enc_options.verbose = 0;
     } else if (!strcmp(argv[c], "-v")) {
       verbose = 1;
       enc_options.verbose = 1;
@@ -304,7 +303,6 @@ int main(int argc, const char *argv[]) {
           GIFClearPic(&frame, NULL);
           WebPPictureCopy(&frame, &curr_canvas);
           WebPPictureCopy(&frame, &prev_canvas);
-          WebPPictureCopy(&frame, &prev_to_prev_canvas);
 
           // Background color.
           GIFGetBackgroundColor(gif->SColorMap, gif->SBackGroundColor,
@@ -341,7 +339,6 @@ int main(int argc, const char *argv[]) {
         }
 
         // Update canvases.
-        GIFCopyPixels(&prev_canvas, &prev_to_prev_canvas);
         GIFDisposeFrame(orig_dispose, &gif_rect, &prev_canvas, &curr_canvas);
         GIFCopyPixels(&curr_canvas, &prev_canvas);
 
@@ -362,6 +359,8 @@ int main(int argc, const char *argv[]) {
         if (DGifGetExtension(gif, &extension, &data) == GIF_ERROR) {
           goto End;
         }
+        if (data == NULL) continue;
+
         switch (extension) {
           case COMMENT_EXT_FUNC_CODE: {
             break;  // Do nothing for now.
@@ -529,7 +528,6 @@ int main(int argc, const char *argv[]) {
   WebPPictureFree(&frame);
   WebPPictureFree(&curr_canvas);
   WebPPictureFree(&prev_canvas);
-  WebPPictureFree(&prev_to_prev_canvas);
   WebPAnimEncoderDelete(enc);
   if (out != NULL && out_file != NULL) fclose(out);
 

examples/gifdec.c

@@ -21,7 +21,7 @@
 #include "webp/encode.h"
 #include "webp/mux_types.h"
 
-#define GIF_TRANSPARENT_COLOR 0x00ffffff
+#define GIF_TRANSPARENT_COLOR 0x00000000
 #define GIF_WHITE_COLOR       0xffffffff
 #define GIF_TRANSPARENT_MASK  0x01
 #define GIF_DISPOSE_MASK      0x07
@@ -81,20 +81,27 @@ int GIFReadGraphicsExtension(const GifByteType* const buf, int* const duration,
   return 1;
 }
 
-static void Remap(const GifFileType* const gif, const uint8_t* const src,
-                  int len, int transparent_index, uint32_t* dst) {
+static int Remap(const GifFileType* const gif, const uint8_t* const src,
+                 int len, int transparent_index, uint32_t* dst) {
   int i;
   const GifColorType* colors;
   const ColorMapObject* const cmap =
       gif->Image.ColorMap ? gif->Image.ColorMap : gif->SColorMap;
-  if (cmap == NULL) return;
+  if (cmap == NULL) return 1;
+  if (cmap->Colors == NULL || cmap->ColorCount <= 0) return 0;
   colors = cmap->Colors;
 
   for (i = 0; i < len; ++i) {
-    const GifColorType c = colors[src[i]];
-    dst[i] = (src[i] == transparent_index) ? GIF_TRANSPARENT_COLOR
-           : c.Blue | (c.Green << 8) | (c.Red << 16) | (0xff << 24);
+    if (src[i] == transparent_index) {
+      dst[i] = GIF_TRANSPARENT_COLOR;
+    } else if (src[i] < cmap->ColorCount) {
+      const GifColorType c = colors[src[i]];
+      dst[i] = c.Blue | (c.Green << 8) | (c.Red << 16) | (0xffu << 24);
+    } else {
+      return 0;
+    }
   }
+  return 1;
 }
 
 int GIFReadFrame(GifFileType* const gif, int transparent_index,
@@ -103,12 +110,18 @@ int GIFReadFrame(GifFileType* const gif, int transparent_index,
   const GifImageDesc* const image_desc = &gif->Image;
   uint32_t* dst = NULL;
   uint8_t* tmp = NULL;
-  int ok = 0;
-  GIFFrameRect rect = {
+  const GIFFrameRect rect = {
       image_desc->Left, image_desc->Top, image_desc->Width, image_desc->Height
   };
+  const uint64_t memory_needed = 4 * rect.width * (uint64_t)rect.height;
+  int ok = 0;
   *gif_rect = rect;
 
+  if (memory_needed != (size_t)memory_needed || memory_needed > (4ULL << 32)) {
+    fprintf(stderr, "Image is too large (%d x %d).", rect.width, rect.height);
+    return 0;
+  }
+
   // Use a view for the sub-picture:
   if (!WebPPictureView(picture, rect.x_offset, rect.y_offset,
                        rect.width, rect.height, &sub_image)) {
@@ -127,20 +140,21 @@ int GIFReadFrame(GifFileType* const gif, int transparent_index,
     const int interlace_jumps[]   = { 8, 8, 4, 2 };
     int pass;
     for (pass = 0; pass < 4; ++pass) {
-      int y;
-      for (y = interlace_offsets[pass]; y < rect.height;
-           y += interlace_jumps[pass]) {
+      const size_t stride = (size_t)sub_image.argb_stride;
+      int y = interlace_offsets[pass];
+      uint32_t* row = dst + y * stride;
+      const size_t jump = interlace_jumps[pass] * stride;
+      for (; y < rect.height; y += interlace_jumps[pass], row += jump) {
         if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
-        Remap(gif, tmp, rect.width, transparent_index,
-              dst + y * sub_image.argb_stride);
+        if (!Remap(gif, tmp, rect.width, transparent_index, row)) goto End;
       }
     }
   } else {  // Non-interlaced image.
     int y;
-    for (y = 0; y < rect.height; ++y) {
+    uint32_t* ptr = dst;
+    for (y = 0; y < rect.height; ++y, ptr += sub_image.argb_stride) {
       if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
-      Remap(gif, tmp, rect.width, transparent_index,
-            dst + y * sub_image.argb_stride);
+      if (!Remap(gif, tmp, rect.width, transparent_index, ptr)) goto End;
     }
   }
   ok = 1;
@@ -216,13 +230,11 @@ int GIFReadMetadata(GifFileType* const gif, GifByteType** const buf,
 
 static void ClearRectangle(WebPPicture* const picture,
                            int left, int top, int width, int height) {
-  int j;
-  for (j = top; j < top + height; ++j) {
-    uint32_t* const dst = picture->argb + j * picture->argb_stride;
-    int i;
-    for (i = left; i < left + width; ++i) {
-      dst[i] = GIF_TRANSPARENT_COLOR;
-    }
+  int i, j;
+  const size_t stride = picture->argb_stride;
+  uint32_t* dst = picture->argb + top * stride + left;
+  for (j = 0; j < height; ++j, dst += stride) {
+    for (i = 0; i < width; ++i) dst[i] = GIF_TRANSPARENT_COLOR;
   }
 }
 
@@ -246,29 +258,31 @@ void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
   if (dispose == GIF_DISPOSE_BACKGROUND) {
     GIFClearPic(curr_canvas, rect);
   } else if (dispose == GIF_DISPOSE_RESTORE_PREVIOUS) {
-    const int src_stride = prev_canvas->argb_stride;
-    const uint32_t* const src =
-        prev_canvas->argb + rect->x_offset + rect->y_offset * src_stride;
-    const int dst_stride = curr_canvas->argb_stride;
-    uint32_t* const dst =
-        curr_canvas->argb + rect->x_offset + rect->y_offset * dst_stride;
+    const size_t src_stride = prev_canvas->argb_stride;
+    const uint32_t* const src = prev_canvas->argb + rect->x_offset
+                              + rect->y_offset * src_stride;
+    const size_t dst_stride = curr_canvas->argb_stride;
+    uint32_t* const dst = curr_canvas->argb + rect->x_offset
+                        + rect->y_offset * dst_stride;
     assert(prev_canvas != NULL);
-    WebPCopyPlane((uint8_t*)src, 4 * src_stride, (uint8_t*)dst, 4 * dst_stride,
+    WebPCopyPlane((uint8_t*)src, (int)(4 * src_stride),
+                  (uint8_t*)dst, (int)(4 * dst_stride),
                   4 * rect->width, rect->height);
   }
 }
 
 void GIFBlendFrames(const WebPPicture* const src,
                     const GIFFrameRect* const rect, WebPPicture* const dst) {
-  int j;
+  int i, j;
+  const size_t src_stride = src->argb_stride;
+  const size_t dst_stride = dst->argb_stride;
   assert(src->width == dst->width && src->height == dst->height);
   for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) {
-    int i;
     for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) {
-      const uint32_t src_pixel = src->argb[j * src->argb_stride + i];
+      const uint32_t src_pixel = src->argb[j * src_stride + i];
       const int src_alpha = src_pixel >> 24;
       if (src_alpha != 0) {
-        dst->argb[j * dst->argb_stride + i] = src_pixel;
+        dst->argb[j * dst_stride + i] = src_pixel;
       }
     }
   }

examples/image_dec.c

@@ -0,0 +1,46 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+// Generic image-type guessing.
+
+#include "./image_dec.h"
+
+static WEBP_INLINE uint32_t GetBE32(const uint8_t buf[]) {
+  return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
+}
+
+WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
+                                       size_t data_size) {
+  WebPInputFileFormat format = WEBP_UNSUPPORTED_FORMAT;
+  if (data != NULL && data_size >= 12) {
+    const uint32_t magic1 = GetBE32(data + 0);
+    const uint32_t magic2 = GetBE32(data + 8);
+    if (magic1 == 0x89504E47U) {
+      format = WEBP_PNG_FORMAT;
+    } else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
+      format = WEBP_JPEG_FORMAT;
+    } else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
+      format = WEBP_TIFF_FORMAT;
+    } else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
+      format = WEBP_WEBP_FORMAT;
+    }
+  }
+  return format;
+}
+
+WebPImageReader WebPGuessImageReader(const uint8_t* const data,
+                                     size_t data_size) {
+  switch (WebPGuessImageType(data, data_size)) {
+    case WEBP_PNG_FORMAT: return ReadPNG;
+    case WEBP_JPEG_FORMAT: return ReadJPEG;
+    case WEBP_TIFF_FORMAT: return ReadTIFF;
+    case WEBP_WEBP_FORMAT: return ReadWebP;
+    default: return NULL;
+  }
+}

examples/image_dec.h

@@ -0,0 +1,61 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+//  All-in-one library to decode PNG/JPEG/WebP/TIFF/WIC input images.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#ifndef WEBP_EXAMPLES_IMAGE_DEC_H_
+#define WEBP_EXAMPLES_IMAGE_DEC_H_
+
+#include "webp/types.h"
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#include "./metadata.h"
+#include "./jpegdec.h"
+#include "./pngdec.h"
+#include "./tiffdec.h"
+#include "./webpdec.h"
+#include "./wicdec.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  WEBP_PNG_FORMAT = 0,
+  WEBP_JPEG_FORMAT,
+  WEBP_TIFF_FORMAT,
+  WEBP_WEBP_FORMAT,
+  WEBP_UNSUPPORTED_FORMAT
+} WebPInputFileFormat;
+
+// 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,
+                                       size_t data_size);
+
+// Signature for common image-reading functions (ReadPNG, ReadJPEG, ...)
+typedef int (*WebPImageReader)(const uint8_t* const data, size_t data_size,
+                               struct WebPPicture* const pic,
+                               int keep_alpha, struct Metadata* const metadata);
+
+// This function is similar to WebPGuessImageType(), but returns a
+// suitable reader function. Or NULL if the image can't be guessed.
+WebPImageReader WebPGuessImageReader(const uint8_t* const data,
+                                     size_t data_size);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  // WEBP_EXAMPLES_IMAGE_DEC_H_

examples/jpegdec.c

@@ -222,10 +222,10 @@ static void ContextInit(j_decompress_ptr cinfo) {
   ctx->pub.bytes_in_buffer = ctx->data_size;
 }
 
-static int ContextFill(j_decompress_ptr cinfo) {
+static boolean ContextFill(j_decompress_ptr cinfo) {
   // we shouldn't get here.
   ERREXIT(cinfo, JERR_FILE_READ);
-  return 0;
+  return FALSE;
 }
 
 static void ContextSkip(j_decompress_ptr cinfo, long jump_size) {
@@ -255,15 +255,18 @@ static void ContextSetup(volatile struct jpeg_decompress_struct* const cinfo,
 }
 
 int ReadJPEG(const uint8_t* const data, size_t data_size,
-             WebPPicture* const pic, Metadata* const metadata) {
+             WebPPicture* const pic, int keep_alpha,
+             Metadata* const metadata) {
   volatile int ok = 0;
-  int stride, width, height;
+  int width, height;
+  int64_t stride;
   volatile struct jpeg_decompress_struct dinfo;
   struct my_error_mgr jerr;
   uint8_t* volatile rgb = NULL;
   JSAMPROW buffer[1];
   JPEGReadContext ctx;
 
+  (void)keep_alpha;
   memset(&ctx, 0, sizeof(ctx));
   ctx.data = data;
   ctx.data_size = data_size;
@@ -295,9 +298,14 @@ int ReadJPEG(const uint8_t* const data, size_t data_size,
 
   width = dinfo.output_width;
   height = dinfo.output_height;
-  stride = dinfo.output_width * dinfo.output_components * sizeof(*rgb);
+  stride = (int64_t)dinfo.output_width * dinfo.output_components * sizeof(*rgb);
 
-  rgb = (uint8_t*)malloc(stride * height);
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    goto End;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * height);
   if (rgb == NULL) {
     goto End;
   }
@@ -324,7 +332,7 @@ int ReadJPEG(const uint8_t* const data, size_t data_size,
   // WebP conversion.
   pic->width = width;
   pic->height = height;
-  ok = WebPPictureImportRGB(pic, rgb, stride);
+  ok = WebPPictureImportRGB(pic, rgb, (int)stride);
   if (!ok) goto Error;
 
  End:
@@ -333,11 +341,12 @@ int ReadJPEG(const uint8_t* const data, size_t data_size,
 }
 #else  // !WEBP_HAVE_JPEG
 int ReadJPEG(const uint8_t* const data, size_t data_size,
-             struct WebPPicture* const pic,
+             struct WebPPicture* const pic, int keep_alpha,
              struct Metadata* const metadata) {
   (void)data;
   (void)data_size;
   (void)pic;
+  (void)keep_alpha;
   (void)metadata;
   fprintf(stderr, "JPEG support not compiled. Please install the libjpeg "
           "development package before building.\n");

examples/jpegdec.h

@@ -25,8 +25,11 @@ struct WebPPicture;
 // Reads a JPEG from 'data', returning the decoded output in 'pic'.
 // The output is RGB or YUV depending on pic->use_argb value.
 // Returns true on success.
+// 'keep_alpha' has no effect, but is kept for coherence with other signatures
+// for image readers.
 int ReadJPEG(const uint8_t* const data, size_t data_size,
-             struct WebPPicture* const pic, struct Metadata* const metadata);
+             struct WebPPicture* const pic, int keep_alpha,
+             struct Metadata* const metadata);
 
 #ifdef __cplusplus
 }    // extern "C"

examples/pngdec.c

@@ -18,7 +18,6 @@
 #include <stdio.h>
 
 #ifdef WEBP_HAVE_PNG
-#include <assert.h>
 #include <png.h>
 #include <setjmp.h>   // note: this must be included *after* png.h
 #include <stdlib.h>
@@ -198,7 +197,9 @@ typedef struct {
 
 static void ReadFunc(png_structp png_ptr, png_bytep data, png_size_t length) {
   PNGReadContext* const ctx = (PNGReadContext*)png_get_io_ptr(png_ptr);
-  assert(ctx->offset + length <= ctx->data_size);
+  if (ctx->data_size - ctx->offset < length) {
+    png_error(png_ptr, "ReadFunc: invalid read length (overflow)!");
+  }
   memcpy(data, ctx->data + ctx->offset, length);
   ctx->offset += length;
 }
@@ -216,7 +217,7 @@ int ReadPNG(const uint8_t* const data, size_t data_size,
   int p;
   volatile int ok = 0;
   png_uint_32 width, height, y;
-  png_uint_32 stride;
+  int64_t stride;
   uint8_t* volatile rgb = NULL;
 
   context.data = data;
@@ -269,8 +270,14 @@ int ReadPNG(const uint8_t* const data, size_t data_size,
 
   num_passes = png_set_interlace_handling(png);
   png_read_update_info(png, info);
-  stride = (has_alpha ? 4 : 3) * width * sizeof(*rgb);
-  rgb = (uint8_t*)malloc(stride * height);
+
+  stride = (int64_t)(has_alpha ? 4 : 3) * width * sizeof(*rgb);
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    goto Error;
+  }
+
+  rgb = (uint8_t*)malloc((size_t)stride * height);
   if (rgb == NULL) goto Error;
   for (p = 0; p < num_passes; ++p) {
     for (y = 0; y < height; ++y) {

examples/tiffdec.c

@@ -22,6 +22,7 @@
 #include <tiffio.h>
 
 #include "webp/encode.h"
+#include "./example_util.h"
 #include "./metadata.h"
 
 static const struct {
@@ -124,6 +125,7 @@ int ReadTIFF(const uint8_t* const data, size_t data_size,
                                    MySize, MyMapFile, MyUnmapFile);
   uint32 width, height;
   uint32* raster;
+  int64_t alloc_size;
   int ok = 0;
   tdir_t dircount;
 
@@ -144,7 +146,16 @@ int ReadTIFF(const uint8_t* const data, size_t data_size,
     fprintf(stderr, "Error! Cannot retrieve TIFF image dimensions.\n");
     goto End;
   }
-  raster = (uint32*)_TIFFmalloc(width * height * sizeof(*raster));
+
+  if (!ImgIoUtilCheckSizeArgumentsOverflow((uint64_t)width * height,
+                                           sizeof(*raster))) {
+    goto End;
+  }
+  // _Tiffmalloc uses a signed type for size.
+  alloc_size = (int64_t)((uint64_t)width * height * sizeof(*raster));
+  if (alloc_size < 0 || alloc_size != (tsize_t)alloc_size) goto End;
+
+  raster = (uint32*)_TIFFmalloc((tsize_t)alloc_size);
   if (raster != NULL) {
     if (TIFFReadRGBAImageOriented(tif, width, height, raster,
                                   ORIENTATION_TOPLEFT, 1)) {

examples/vwebp.c

@@ -14,6 +14,10 @@
 #include "webp/config.h"
 #endif
 
+#if defined(__unix__) || defined(__CYGWIN__)
+#define _POSIX_C_SOURCE 200112L  // for setenv
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -63,6 +67,7 @@ static struct {
   WebPIterator curr_frame;
   WebPIterator prev_frame;
   WebPChunkIterator iccp;
+  int viewport_width, viewport_height;
 } kParams;
 
 static void ClearPreviousPic(void) {
@@ -242,18 +247,24 @@ static void HandleKey(unsigned char key, int pos_x, int pos_y) {
     }
   } else if (key == 'i') {
     kParams.print_info = 1 - kParams.print_info;
+    // TODO(skal): handle refresh of animation's last-frame too. It's quite
+    // more involved though (need to save the previous frame).
+    if (!kParams.has_animation) ClearPreviousFrame();
     glutPostRedisplay();
   }
 }
 
 static void HandleReshape(int width, int height) {
-  // TODO(skal): proper handling of resize, esp. for large pictures.
-  // + key control of the zoom.
+  // TODO(skal): should we preserve aspect ratio?
+  // Also: handle larger-than-screen pictures correctly.
   glViewport(0, 0, width, height);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
+  kParams.viewport_width = width;
+  kParams.viewport_height = height;
+  if (!kParams.has_animation) ClearPreviousFrame();
 }
 
 static void PrintString(const char* const text) {
@@ -295,7 +306,8 @@ static void HandleDisplay(void) {
   GLfloat xoff, yoff;
   if (pic == NULL) return;
   glPushMatrix();
-  glPixelZoom(1, -1);
+  glPixelZoom((GLfloat)(+1. / kParams.canvas_width * kParams.viewport_width),
+              (GLfloat)(-1. / kParams.canvas_height * kParams.viewport_height));
   xoff = (GLfloat)(2. * curr->x_offset / kParams.canvas_width);
   yoff = (GLfloat)(2. * curr->y_offset / kParams.canvas_height);
   glRasterPos2f(-1.f + xoff, 1.f - yoff);
@@ -304,8 +316,6 @@ static void HandleDisplay(void) {
 
   if (prev->dispose_method == WEBP_MUX_DISPOSE_BACKGROUND ||
       curr->blend_method == WEBP_MUX_NO_BLEND) {
-    // TODO(later): these offsets and those above should factor in window size.
-    //              they will be incorrect if the window is resized.
     // glScissor() takes window coordinates (0,0 at bottom left).
     int window_x, window_y;
     int frame_w, frame_h;
@@ -325,6 +335,10 @@ static void HandleDisplay(void) {
     }
     glEnable(GL_SCISSOR_TEST);
     // Only update the requested area, not the whole canvas.
+    window_x = window_x * kParams.viewport_width / kParams.canvas_width;
+    window_y = window_y * kParams.viewport_height / kParams.canvas_height;
+    frame_w = frame_w * kParams.viewport_width / kParams.canvas_width;
+    frame_h = frame_h * kParams.viewport_height / kParams.canvas_height;
     glScissor(window_x, window_y, frame_w, frame_h);
 
     glClear(GL_COLOR_BUFFER_BIT);  // use clear color
@@ -367,6 +381,7 @@ static void StartDisplay(void) {
   glutInitWindowSize(width, height);
   glutCreateWindow("WebP viewer");
   glutDisplayFunc(HandleDisplay);
+  glutReshapeFunc(HandleReshape);
   glutIdleFunc(NULL);
   glutKeyboardFunc(HandleKey);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
@@ -375,7 +390,6 @@ static void StartDisplay(void) {
                GetColorf(kParams.bg_color, 8),
                GetColorf(kParams.bg_color, 16),
                GetColorf(kParams.bg_color, 24));
-  HandleReshape(width, height);
   glClear(GL_COLOR_BUFFER_BIT);
   DrawCheckerBoard();
 }
@@ -387,7 +401,7 @@ static void Help(void) {
   printf("Usage: vwebp in_file [options]\n\n"
          "Decodes the WebP image file and visualize it using OpenGL\n"
          "Options are:\n"
-         "  -version  .... print version number and exit\n"
+         "  -version ..... print version number and exit\n"
          "  -noicc ....... don't use the icc profile if present\n"
          "  -nofancy ..... don't use the fancy YUV420 upscaler\n"
          "  -nofilter .... disable in-loop filtering\n"
@@ -395,7 +409,7 @@ static void Help(void) {
          "  -noalphadither disable alpha plane dithering\n"
          "  -mt .......... use multi-threading\n"
          "  -info ........ print info\n"
-         "  -h     ....... this help message\n"
+         "  -h ........... this help message\n"
          "\n"
          "Keyboard shortcuts:\n"
          "  'c' ................ toggle use of color profile\n"

examples/webpdec.c

@@ -45,18 +45,42 @@ int ReadWebP(const uint8_t* const data, size_t data_size,
   }
   {
     const int has_alpha = keep_alpha && bitstream->has_alpha;
-    // TODO(skal): use MODE_YUV(A), depending on the expected
-    // input pic->use_argb. This would save some conversion steps.
-    output_buffer->colorspace = has_alpha ? MODE_RGBA : MODE_RGB;
+    if (pic->use_argb) {
+      output_buffer->colorspace = has_alpha ? MODE_RGBA : MODE_RGB;
+    } else {
+      output_buffer->colorspace = has_alpha ? MODE_YUVA : MODE_YUV;
+    }
 
     status = ExUtilDecodeWebP(data, data_size, 0, &config);
     if (status == VP8_STATUS_OK) {
-      const uint8_t* const rgba = output_buffer->u.RGBA.rgba;
-      const int stride = output_buffer->u.RGBA.stride;
       pic->width = output_buffer->width;
       pic->height = output_buffer->height;
-      ok = has_alpha ? WebPPictureImportRGBA(pic, rgba, stride)
-                     : WebPPictureImportRGB(pic, rgba, stride);
+      if (pic->use_argb) {
+        const uint8_t* const rgba = output_buffer->u.RGBA.rgba;
+        const int stride = output_buffer->u.RGBA.stride;
+        ok = has_alpha ? WebPPictureImportRGBA(pic, rgba, stride)
+                       : WebPPictureImportRGB(pic, rgba, stride);
+      } else {
+        pic->colorspace = has_alpha ? WEBP_YUV420A : WEBP_YUV420;
+        ok = WebPPictureAlloc(pic);
+        if (!ok) {
+          status = VP8_STATUS_OUT_OF_MEMORY;
+        } else {
+          const WebPYUVABuffer* const yuva = &output_buffer->u.YUVA;
+          const int uv_width = (pic->width + 1) >> 1;
+          const int uv_height = (pic->height + 1) >> 1;
+          ExUtilCopyPlane(yuva->y, yuva->y_stride,
+                          pic->y, pic->y_stride, pic->width, pic->height);
+          ExUtilCopyPlane(yuva->u, yuva->u_stride,
+                          pic->u, pic->uv_stride, uv_width, uv_height);
+          ExUtilCopyPlane(yuva->v, yuva->v_stride,
+                          pic->v, pic->uv_stride, uv_width, uv_height);
+          if (has_alpha) {
+            ExUtilCopyPlane(yuva->a, yuva->a_stride,
+                            pic->a, pic->a_stride, pic->width, pic->height);
+          }
+        }
+      }
     }
   }
 

examples/wicdec.c

@@ -274,7 +274,7 @@ int ReadPictureWithWIC(const char* const filename,
     NULL
   };
   int has_alpha = 0;
-  int stride;
+  int64_t stride;
 
   IFS(CoInitialize(NULL));
   IFS(CoCreateInstance(MAKE_REFGUID(CLSID_WICImagingFactory), NULL,
@@ -334,14 +334,19 @@ int ReadPictureWithWIC(const char* const filename,
 
   // Decode.
   IFS(IWICFormatConverter_GetSize(converter, &width, &height));
-  stride = importer->bytes_per_pixel * width * sizeof(*rgb);
+  stride = (int64_t)importer->bytes_per_pixel * width * sizeof(*rgb);
+  if (stride != (int)stride ||
+      !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
+    hr = E_FAIL;
+  }
+
   if (SUCCEEDED(hr)) {
-    rgb = (BYTE*)malloc(stride * height);
+    rgb = (BYTE*)malloc((size_t)stride * height);
     if (rgb == NULL)
       hr = E_OUTOFMEMORY;
   }
   IFS(IWICFormatConverter_CopyPixels(converter, NULL,
-                                     stride, stride * height, rgb));
+                                     (UINT)stride, (UINT)stride * height, rgb));
 
   // WebP conversion.
   if (SUCCEEDED(hr)) {
@@ -349,7 +354,7 @@ int ReadPictureWithWIC(const char* const filename,
     pic->width = width;
     pic->height = height;
     pic->use_argb = 1;    // For WIC, we always force to argb
-    ok = importer->import(pic, rgb, stride);
+    ok = importer->import(pic, rgb, (int)stride);
     if (!ok) hr = E_FAIL;
   }
   if (SUCCEEDED(hr)) {

gradle.properties

@@ -0,0 +1,14 @@
+# Project-wide Gradle settings.
+
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+
+# Versions for gradle
+BUILD_TOOLS_VERSION=23.0.3
+COMPILE_SDK_VERSION=23
+ANDROID_GRADLE_PLUGIN_VERSION=1.5.0
+GRADLE_DOWNLOAD_TASK_VERSION=2.1.0

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Thu May 12 17:06:25 CEST 2016
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.13-bin.zip

gradlew

@@ -0,0 +1,164 @@
+#!/usr/bin/env bash
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn ( ) {
+    echo "$*"
+}
+
+die ( ) {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
+function splitJvmOpts() {
+    JVM_OPTS=("$@")
+}
+eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
+JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+
+exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"

gradlew.bat

@@ -0,0 +1,90 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+if "%@eval[2+2]" == "4" goto 4NT_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+goto execute
+
+:4NT_args
+@rem Get arguments from the 4NT Shell from JP Software
+set CMD_LINE_ARGS=%$
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

iosbuild.sh

@@ -1,10 +1,11 @@
 #!/bin/bash
 #
-# This script generates 'WebP.framework'. An iOS app can decode WebP images
-# by including 'WebP.framework'.
+# This script generates 'WebP.framework' and 'WebPDecoder.framework'. An iOS
+# app can decode WebP images by including 'WebPDecoder.framework' and both
+# encode and decode WebP images by including 'WebP.framework'.
 #
-# Run ./iosbuild.sh to generate 'WebP.framework' under the current directory
-# (previous build will be erased if it exists).
+# Run ./iosbuild.sh to generate the frameworks under the current directory
+# (the previous build will be erased if it exists).
 #
 # This script is inspired by the build script written by Carson McDonald.
 # (http://www.ioncannon.net/programming/1483/using-webp-to-reduce-native-ios-app-size/).
@@ -33,10 +34,12 @@ readonly SRCDIR=$(dirname $0)
 readonly TOPDIR=$(pwd)
 readonly BUILDDIR="${TOPDIR}/iosbuild"
 readonly TARGETDIR="${TOPDIR}/WebP.framework"
+readonly DECTARGETDIR="${TOPDIR}/WebPDecoder.framework"
 readonly DEVELOPER=$(xcode-select --print-path)
 readonly PLATFORMSROOT="${DEVELOPER}/Platforms"
 readonly LIPO=$(xcrun -sdk iphoneos${SDK} -find lipo)
 LIBLIST=''
+DECLIBLIST=''
 
 if [[ -z "${SDK}" ]]; then
   echo "iOS SDK not available"
@@ -50,10 +53,8 @@ else
   echo "iOS SDK Version ${SDK}"
 fi
 
-rm -rf ${BUILDDIR}
-rm -rf ${TARGETDIR}
-mkdir -p ${BUILDDIR}
-mkdir -p ${TARGETDIR}/Headers/
+rm -rf ${BUILDDIR} ${TARGETDIR} ${DECTARGETDIR}
+mkdir -p ${BUILDDIR} ${TARGETDIR}/Headers/ ${DECTARGETDIR}/Headers/
 
 if [[ ! -e ${SRCDIR}/configure ]]; then
   if ! (cd ${SRCDIR} && sh autogen.sh); then
@@ -107,12 +108,13 @@ for PLATFORM in ${PLATFORMS}; do
     CFLAGS="${CFLAGS}"
   set +x
 
-  # run make only in the src/ directory to create libwebpdecoder.a
+  # run make only in the src/ directory to create libwebp.a/libwebpdecoder.a
   cd src/
   make V=0
   make install
 
-  LIBLIST+=" ${ROOTDIR}/lib/libwebpdecoder.a"
+  LIBLIST+=" ${ROOTDIR}/lib/libwebp.a"
+  DECLIBLIST+=" ${ROOTDIR}/lib/libwebpdecoder.a"
 
   make clean
   cd ..
@@ -122,3 +124,6 @@ done
 
 cp -a ${SRCDIR}/src/webp/*.h ${TARGETDIR}/Headers/
 ${LIPO} -create ${LIBLIST} -output ${TARGETDIR}/WebP
+
+cp -a ${SRCDIR}/src/webp/*.h ${DECTARGETDIR}/Headers/
+${LIPO} -create ${DECLIBLIST} -output ${DECTARGETDIR}/WebPDecoder

makefile.unix

@@ -89,6 +89,14 @@ endif
 # EXTRA_FLAGS += -march=armv7-a -mfloat-abi=hard -mfpu=neon -mtune=cortex-a8
 # -> seems to make the overall lib slower: -fno-split-wide-types
 
+# MIPS (MSA) 32-bit build specific flags for mips32r5 (p5600):
+# EXTRA_FLAGS += -mips32r5 -mabi=32 -mtune=p5600 -mmsa -mfp64
+# EXTRA_FLAGS += -msched-weight -mload-store-pairs
+
+# MIPS (MSA) 64-bit build specific flags for mips64r6 (i6400):
+# EXTRA_FLAGS += -mips64r6 -mabi=64 -mtune=i6400 -mmsa -mfp64
+# EXTRA_FLAGS += -msched-weight -mload-store-pairs
+
 #### Nothing should normally be changed below this line ####
 
 AR = ar
@@ -130,6 +138,7 @@ DSP_DEC_OBJS = \
     src/dsp/dec_clip_tables.o \
     src/dsp/dec_mips32.o \
     src/dsp/dec_mips_dsp_r2.o \
+    src/dsp/dec_msa.o \
     src/dsp/dec_neon.o \
     src/dsp/dec_sse2.o \
     src/dsp/dec_sse41.o \
@@ -201,6 +210,7 @@ ENC_OBJS = \
     src/enc/webpenc.o \
 
 EX_FORMAT_DEC_OBJS = \
+    examples/image_dec.o \
     examples/jpegdec.o \
     examples/metadata.o \
     examples/pngdec.o \
@@ -260,9 +270,11 @@ HDRS = \
     src/dec/vp8i.h \
     src/dec/vp8li.h \
     src/dec/webpi.h \
+    src/dsp/common_sse2.h \
     src/dsp/dsp.h \
     src/dsp/lossless.h \
     src/dsp/mips_macro.h \
+    src/dsp/msa_macro.h \
     src/dsp/neon.h \
     src/dsp/yuv.h \
     src/enc/backward_references.h \
@@ -320,6 +332,7 @@ src/utils/bit_writer.o: src/utils/endian_inl.h
 	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
 
 examples/libanim_util.a: $(ANIM_UTIL_OBJS)
+examples/libexample_dec.a: $(EX_FORMAT_DEC_OBJS)
 examples/libexample_util.a: $(EX_UTIL_OBJS)
 examples/libgifdec.a: $(GIFDEC_OBJS)
 src/libwebpdecoder.a: $(LIBWEBPDECODER_OBJS)
@@ -332,7 +345,7 @@ src/libwebpextras.a: $(LIBWEBPEXTRA_OBJS)
 	$(AR) $(ARFLAGS) $@ $^
 
 examples/anim_diff: examples/anim_diff.o $(ANIM_UTIL_OBJS) $(GIFDEC_OBJS)
-examples/cwebp: examples/cwebp.o $(EX_FORMAT_DEC_OBJS)
+examples/cwebp: examples/cwebp.o
 examples/dwebp: examples/dwebp.o
 examples/gif2webp: examples/gif2webp.o $(GIFDEC_OBJS)
 examples/vwebp: examples/vwebp.o
@@ -343,7 +356,8 @@ examples/anim_diff: src/demux/libwebpdemux.a examples/libexample_util.a
 examples/anim_diff: src/libwebp.a
 examples/anim_diff: EXTRA_LIBS += $(GIF_LIBS)
 examples/anim_diff: EXTRA_FLAGS += -DWEBP_HAVE_GIF
-examples/cwebp: examples/libexample_util.a src/libwebp.a
+examples/cwebp: examples/libexample_util.a examples/libexample_dec.a
+examples/cwebp: src/libwebp.a
 examples/cwebp: EXTRA_LIBS += $(CWEBP_LIBS)
 examples/dwebp: examples/libexample_util.a src/libwebpdecoder.a
 examples/dwebp: EXTRA_LIBS += $(DWEBP_LIBS)

man/cwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH CWEBP 1 "December 14, 2015"
+.TH CWEBP 1 "September 02, 2016"
 .SH NAME
 cwebp \- compress an image file to a WebP file
 .SH SYNOPSIS
@@ -117,17 +117,21 @@ or without alpha).
 .TP
 .BI \-size " int
 Specify a target size (in bytes) to try and reach for the compressed output.
-Compressor will make several pass of partial encoding in order to get as
-close as possible to this target.
+The compressor will make several passes of partial encoding in order to get as
+close as possible to this target. If both \fB\-size\fP and \fB\-psnr\fP
+are used, \fB\-size\fP value will prevail.
 .TP
 .BI \-psnr " float
 Specify a target PSNR (in dB) to try and reach for the compressed output.
-Compressor will make several pass of partial encoding in order to get as
-close as possible to this target.
+The compressor will make several passes of partial encoding in order to get as
+close as possible to this target. If both \fB\-size\fP and \fB\-psnr\fP
+are used, \fB\-size\fP value will prevail.
 .TP
 .BI \-pass " int
 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.
 .TP
 .B \-af
 Turns auto\-filter on. This algorithm will spend additional time optimizing
@@ -167,7 +171,7 @@ Specify the amplitude of the spatial noise shaping. Spatial noise shaping
 (or \fBsns\fP for short) refers to a general collection of built\-in algorithms
 used to decide which area of the picture should use relatively less bits,
 and where else to better transfer these bits. The possible range goes from
-0 (algorithm is off) to 100 (the maximal effect). The default value is 80.
+0 (algorithm is off) to 100 (the maximal effect). The default value is 50.
 .TP
 .BI \-segments " int
 Change the number of partitions to use during the segmentation of the
@@ -218,7 +222,7 @@ Report encoding progress in percent.
 Do not print anything.
 .TP
 .B \-short
-Only print brief information (output file size and PSNR) for testing purpose.
+Only print brief information (output file size and PSNR) for testing purposes.
 .TP
 .BI \-map " int
 Output additional ASCII\-map of encoding information. Possible map values
@@ -277,7 +281,7 @@ Note: each input format may not support all combinations.
 Disable all assembly optimizations.
 
 .SH BUGS
-Please report all bugs to our issue tracker:
+Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp
 .br
 Patches welcome! See this page to get started:

man/dwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH DWEBP 1 "December 11, 2015"
+.TH DWEBP 1 "June 23, 2016"
 .SH NAME
 dwebp \- decompress a WebP file to an image file
 .SH SYNOPSIS
@@ -108,7 +108,7 @@ Print extra information (decoding time in particular).
 Disable all assembly optimizations.
 
 .SH BUGS
-Please report all bugs to our issue tracker:
+Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp
 .br
 Patches welcome! See this page to get started:

man/gif2webp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH GIF2WEBP 1 "December 11, 2015"
+.TH GIF2WEBP 1 "June 23, 2016"
 .SH NAME
 gif2webp \- Convert a GIF image to WebP
 .SH SYNOPSIS
@@ -117,7 +117,7 @@ Print extra information.
 Do not print anything.
 
 .SH BUGS
-Please report all bugs to our issue tracker:
+Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp
 .br
 Patches welcome! See this page to get started:

man/vwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH VWEBP 1 "December 11, 2015"
+.TH VWEBP 1 "June 23, 2016"
 .SH NAME
 vwebp \- decompress a WebP file and display it in a window
 .SH SYNOPSIS
@@ -63,7 +63,7 @@ Overlay file information.
 Quit.
 
 .SH BUGS
-Please report all bugs to our issue tracker:
+Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp
 .br
 Patches welcome! See this page to get started:

man/webpmux.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH WEBPMUX 1 "December 11, 2015"
+.TH WEBPMUX 1 "June 23, 2016"
 .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.
@@ -128,7 +128,7 @@ Output file in WebP format.
 The nature of EXIF, XMP and ICC data is not checked and is assumed to be valid.
 
 .SH BUGS
-Please report all bugs to our issue tracker:
+Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp
 .br
 Patches welcome! See this page to get started:

src/Makefile.am

@@ -38,7 +38,7 @@ 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 6:0:0
+libwebp_la_LDFLAGS = -no-undefined -version-info 6:2:0
 libwebpincludedir = $(includedir)/webp
 pkgconfig_DATA = libwebp.pc
 
@@ -50,7 +50,7 @@ if BUILD_LIBWEBPDECODER
   libwebpdecoder_la_LIBADD += dsp/libwebpdspdecode.la
   libwebpdecoder_la_LIBADD += utils/libwebputilsdecode.la
 
-  libwebpdecoder_la_LDFLAGS = -no-undefined -version-info 2:0:0
+  libwebpdecoder_la_LDFLAGS = -no-undefined -version-info 2:2:0
   pkgconfig_DATA += libwebpdecoder.pc
 endif
 

src/dec/alpha.c

@@ -23,12 +23,14 @@
 //------------------------------------------------------------------------------
 // ALPHDecoder object.
 
-ALPHDecoder* ALPHNew(void) {
+// Allocates a new alpha decoder instance.
+static ALPHDecoder* ALPHNew(void) {
   ALPHDecoder* const dec = (ALPHDecoder*)WebPSafeCalloc(1ULL, sizeof(*dec));
   return dec;
 }
 
-void ALPHDelete(ALPHDecoder* const dec) {
+// Clears and deallocates an alpha decoder instance.
+static void ALPHDelete(ALPHDecoder* const dec) {
   if (dec != NULL) {
     VP8LDelete(dec->vp8l_dec_);
     dec->vp8l_dec_ = NULL;
@@ -44,24 +46,28 @@ void ALPHDelete(ALPHDecoder* const dec) {
 // 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, int width, int height, uint8_t* output) {
+                    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;
   int rsrv;
+  VP8Io* const io = &dec->io_;
 
-  assert(width > 0 && height > 0);
-  assert(data != NULL && output != NULL);
+  assert(data != NULL && output != NULL && src_io != NULL);
 
-  dec->width_ = width;
-  dec->height_ = height;
+  VP8FiltersInit();
+  dec->output_ = output;
+  dec->width_ = src_io->width;
+  dec->height_ = src_io->height;
+  assert(dec->width_ > 0 && dec->height_ > 0);
 
   if (data_size <= ALPHA_HEADER_LEN) {
     return 0;
   }
 
   dec->method_ = (data[0] >> 0) & 0x03;
-  dec->filter_ = (data[0] >> 2) & 0x03;
+  dec->filter_ = (WEBP_FILTER_TYPE)((data[0] >> 2) & 0x03);
   dec->pre_processing_ = (data[0] >> 4) & 0x03;
   rsrv = (data[0] >> 6) & 0x03;
   if (dec->method_ < ALPHA_NO_COMPRESSION ||
@@ -72,14 +78,28 @@ static int ALPHInit(ALPHDecoder* const dec, const uint8_t* data,
     return 0;
   }
 
+  // Copy the necessary parameters from src_io to io
+  VP8InitIo(io);
+  WebPInitCustomIo(NULL, io);
+  io->opaque = dec;
+  io->width = src_io->width;
+  io->height = src_io->height;
+
+  io->use_cropping = src_io->use_cropping;
+  io->crop_left = src_io->crop_left;
+  io->crop_right = src_io->crop_right;
+  io->crop_top = src_io->crop_top;
+  io->crop_bottom = src_io->crop_bottom;
+  // No need to copy the scaling parameters.
+
   if (dec->method_ == ALPHA_NO_COMPRESSION) {
     const size_t alpha_decoded_size = dec->width_ * dec->height_;
     ok = (alpha_data_size >= alpha_decoded_size);
   } else {
     assert(dec->method_ == ALPHA_LOSSLESS_COMPRESSION);
-    ok = VP8LDecodeAlphaHeader(dec, alpha_data, alpha_data_size, output);
+    ok = VP8LDecodeAlphaHeader(dec, alpha_data, alpha_data_size);
   }
-  VP8FiltersInit();
+
   return ok;
 }
 
@@ -90,15 +110,30 @@ static int ALPHInit(ALPHDecoder* const dec, const uint8_t* data,
 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->height_;
-  WebPUnfilterFunc unfilter_func = WebPUnfilters[alph_dec->filter_];
-  uint8_t* const output = dec->alpha_plane_;
+  const int height = alph_dec->io_.crop_bottom;
   if (alph_dec->method_ == ALPHA_NO_COMPRESSION) {
-    const size_t offset = row * width;
-    const size_t num_pixels = num_rows * width;
-    assert(dec->alpha_data_size_ >= ALPHA_HEADER_LEN + offset + num_pixels);
-    memcpy(dec->alpha_plane_ + offset,
-           dec->alpha_data_ + ALPHA_HEADER_LEN + offset, num_pixels);
+    int y;
+    const uint8_t* prev_line = dec->alpha_prev_line_;
+    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;
+      }
+    }
+    dec->alpha_prev_line_ = prev_line;
   } else {  // alph_dec->method_ == ALPHA_LOSSLESS_COMPRESSION
     assert(alph_dec->vp8l_dec_ != NULL);
     if (!VP8LDecodeAlphaImageStream(alph_dec, row + num_rows)) {
@@ -106,62 +141,92 @@ static int ALPHDecode(VP8Decoder* const dec, int row, int num_rows) {
     }
   }
 
-  if (unfilter_func != NULL) {
-    unfilter_func(width, height, width, row, num_rows, output);
-  }
-
-  if (row + num_rows == dec->pic_hdr_.height_) {
+  if (row + num_rows >= height) {
     dec->is_alpha_decoded_ = 1;
   }
   return 1;
 }
 
+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;
+  assert(dec->alpha_plane_mem_ == NULL);
+  dec->alpha_plane_mem_ =
+      (uint8_t*)WebPSafeMalloc(alpha_size, sizeof(*dec->alpha_plane_));
+  if (dec->alpha_plane_mem_ == NULL) {
+    return 0;
+  }
+  dec->alpha_plane_ = dec->alpha_plane_mem_;
+  dec->alpha_prev_line_ = NULL;
+  return 1;
+}
+
+void WebPDeallocateAlphaMemory(VP8Decoder* const dec) {
+  assert(dec != NULL);
+  WebPSafeFree(dec->alpha_plane_mem_);
+  dec->alpha_plane_mem_ = NULL;
+  dec->alpha_plane_ = NULL;
+  ALPHDelete(dec->alph_dec_);
+  dec->alph_dec_ = NULL;
+}
+
 //------------------------------------------------------------------------------
 // Main entry point.
 
 const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
+                                      const VP8Io* const io,
                                       int row, int num_rows) {
-  const int width = dec->pic_hdr_.width_;
-  const int height = dec->pic_hdr_.height_;
+  const int width = io->width;
+  const int height = io->crop_bottom;
+
+  assert(dec != NULL && io != NULL);
 
   if (row < 0 || num_rows <= 0 || row + num_rows > height) {
     return NULL;    // sanity check.
   }
 
-  if (row == 0) {
-    // Initialize decoding.
-    assert(dec->alpha_plane_ != NULL);
-    dec->alph_dec_ = ALPHNew();
-    if (dec->alph_dec_ == NULL) return NULL;
-    if (!ALPHInit(dec->alph_dec_, dec->alpha_data_, dec->alpha_data_size_,
-                  width, height, dec->alpha_plane_)) {
-      ALPHDelete(dec->alph_dec_);
-      dec->alph_dec_ = NULL;
-      return NULL;
-    }
-    // if we allowed use of alpha dithering, check whether it's needed at all
-    if (dec->alph_dec_->pre_processing_ != ALPHA_PREPROCESSED_LEVELS) {
-      dec->alpha_dithering_ = 0;  // disable dithering
-    } else {
-      num_rows = height;          // decode everything in one pass
-    }
-  }
-
   if (!dec->is_alpha_decoded_) {
-    int ok = 0;
-    assert(dec->alph_dec_ != NULL);
-    ok = ALPHDecode(dec, row, num_rows);
-    if (ok && dec->alpha_dithering_ > 0) {
-      ok = WebPDequantizeLevels(dec->alpha_plane_, width, height,
-                                dec->alpha_dithering_);
+    if (dec->alph_dec_ == NULL) {    // Initialize decoder.
+      dec->alph_dec_ = ALPHNew();
+      if (dec->alph_dec_ == NULL) return NULL;
+      if (!AllocateAlphaPlane(dec, io)) goto Error;
+      if (!ALPHInit(dec->alph_dec_, dec->alpha_data_, dec->alpha_data_size_,
+                    io, dec->alpha_plane_)) {
+        goto Error;
+      }
+      // if we allowed use of alpha dithering, check whether it's needed at all
+      if (dec->alph_dec_->pre_processing_ != ALPHA_PREPROCESSED_LEVELS) {
+        dec->alpha_dithering_ = 0;   // disable dithering
+      } else {
+        num_rows = height - row;     // decode everything in one pass
+      }
     }
-    if (!ok || dec->is_alpha_decoded_) {
+
+    assert(dec->alph_dec_ != NULL);
+    assert(row + num_rows <= height);
+    if (!ALPHDecode(dec, row, num_rows)) goto Error;
+
+    if (dec->is_alpha_decoded_) {   // finished?
       ALPHDelete(dec->alph_dec_);
       dec->alph_dec_ = NULL;
+      if (dec->alpha_dithering_ > 0) {
+        uint8_t* const alpha = dec->alpha_plane_ + io->crop_top * width
+                             + io->crop_left;
+        if (!WebPDequantizeLevels(alpha,
+                                  io->crop_right - io->crop_left,
+                                  io->crop_bottom - io->crop_top,
+                                  width, dec->alpha_dithering_)) {
+          goto Error;
+        }
+      }
     }
-    if (!ok) return NULL;  // Error.
   }
 
   // Return a pointer to the current decoded row.
   return dec->alpha_plane_ + row * width;
+
+ Error:
+  WebPDeallocateAlphaMemory(dec);
+  return NULL;
 }

src/dec/alphai.h

@@ -32,19 +32,18 @@ struct ALPHDecoder {
   int pre_processing_;
   struct VP8LDecoder* vp8l_dec_;
   VP8Io io_;
-  int use_8b_decode;  // Although alpha channel requires only 1 byte per
-                      // pixel, sometimes VP8LDecoder may need to allocate
-                      // 4 bytes per pixel internally during decode.
+  int use_8b_decode_;  // Although alpha channel requires only 1 byte per
+                       // pixel, sometimes VP8LDecoder may need to allocate
+                       // 4 bytes per pixel internally during decode.
+  uint8_t* output_;
+  const uint8_t* prev_line_;   // last output row (or NULL)
 };
 
 //------------------------------------------------------------------------------
 // internal functions. Not public.
 
-// Allocates a new alpha decoder instance.
-ALPHDecoder* ALPHNew(void);
-
-// Clears and deallocates an alpha decoder instance.
-void ALPHDelete(ALPHDecoder* const dec);
+// Deallocate memory associated to dec->alpha_plane_ decoding
+void WebPDeallocateAlphaMemory(VP8Decoder* const dec);
 
 //------------------------------------------------------------------------------
 

src/dec/buffer.c

@@ -92,7 +92,7 @@ static VP8StatusCode AllocateBuffer(WebPDecBuffer* const buffer) {
     return VP8_STATUS_INVALID_PARAM;
   }
 
-  if (!buffer->is_external_memory && buffer->private_memory == NULL) {
+  if (buffer->is_external_memory <= 0 && buffer->private_memory == NULL) {
     uint8_t* output;
     int uv_stride = 0, a_stride = 0;
     uint64_t uv_size = 0, a_size = 0, total_size;
@@ -227,7 +227,7 @@ int WebPInitDecBufferInternal(WebPDecBuffer* buffer, int version) {
 
 void WebPFreeDecBuffer(WebPDecBuffer* buffer) {
   if (buffer != NULL) {
-    if (!buffer->is_external_memory) {
+    if (buffer->is_external_memory <= 0) {
       WebPSafeFree(buffer->private_memory);
     }
     buffer->private_memory = NULL;
@@ -256,5 +256,45 @@ void WebPGrabDecBuffer(WebPDecBuffer* const src, WebPDecBuffer* const dst) {
   }
 }
 
-//------------------------------------------------------------------------------
+VP8StatusCode WebPCopyDecBufferPixels(const WebPDecBuffer* const src_buf,
+                                      WebPDecBuffer* const dst_buf) {
+  assert(src_buf != NULL && dst_buf != NULL);
+  assert(src_buf->colorspace == dst_buf->colorspace);
 
+  dst_buf->width = src_buf->width;
+  dst_buf->height = src_buf->height;
+  if (CheckDecBuffer(dst_buf) != VP8_STATUS_OK) {
+    return VP8_STATUS_INVALID_PARAM;
+  }
+  if (WebPIsRGBMode(src_buf->colorspace)) {
+    const WebPRGBABuffer* const src = &src_buf->u.RGBA;
+    const WebPRGBABuffer* const dst = &dst_buf->u.RGBA;
+    WebPCopyPlane(src->rgba, src->stride, dst->rgba, dst->stride,
+                  src_buf->width * kModeBpp[src_buf->colorspace],
+                  src_buf->height);
+  } else {
+    const WebPYUVABuffer* const src = &src_buf->u.YUVA;
+    const WebPYUVABuffer* const dst = &dst_buf->u.YUVA;
+    WebPCopyPlane(src->y, src->y_stride, dst->y, dst->y_stride,
+                  src_buf->width, src_buf->height);
+    WebPCopyPlane(src->u, src->u_stride, dst->u, dst->u_stride,
+                  (src_buf->width + 1) / 2, (src_buf->height + 1) / 2);
+    WebPCopyPlane(src->v, src->v_stride, dst->v, dst->v_stride,
+                  (src_buf->width + 1) / 2, (src_buf->height + 1) / 2);
+    if (WebPIsAlphaMode(src_buf->colorspace)) {
+      WebPCopyPlane(src->a, src->a_stride, dst->a, dst->a_stride,
+                    src_buf->width, src_buf->height);
+    }
+  }
+  return VP8_STATUS_OK;
+}
+
+int WebPAvoidSlowMemory(const WebPDecBuffer* const output,
+                        const WebPBitstreamFeatures* const features) {
+  assert(output != NULL);
+  return (output->is_external_memory >= 2) &&
+         WebPIsPremultipliedMode(output->colorspace) &&
+         (features != NULL && features->has_alpha);
+}
+
+//------------------------------------------------------------------------------

src/dec/frame.c

@@ -316,6 +316,9 @@ static void PrecomputeFilterStrengths(VP8Decoder* const dec) {
 //------------------------------------------------------------------------------
 // Dithering
 
+// minimal amp that will provide a non-zero dithering effect
+#define MIN_DITHER_AMP 4
+
 #define DITHER_AMP_TAB_SIZE 12
 static const int kQuantToDitherAmp[DITHER_AMP_TAB_SIZE] = {
   // roughly, it's dqm->uv_mat_[1]
@@ -356,27 +359,14 @@ void VP8InitDithering(const WebPDecoderOptions* const options,
   }
 }
 
-// minimal amp that will provide a non-zero dithering effect
-#define MIN_DITHER_AMP 4
-#define DITHER_DESCALE 4
-#define DITHER_DESCALE_ROUNDER (1 << (DITHER_DESCALE - 1))
-#define DITHER_AMP_BITS 8
-#define DITHER_AMP_CENTER (1 << DITHER_AMP_BITS)
-
+// Convert to range: [-2,2] for dither=50, [-4,4] for dither=100
 static void Dither8x8(VP8Random* const rg, uint8_t* dst, int bps, int amp) {
-  int i, j;
-  for (j = 0; j < 8; ++j) {
-    for (i = 0; i < 8; ++i) {
-      // TODO: could be made faster with SSE2
-      const int bits =
-          VP8RandomBits2(rg, DITHER_AMP_BITS + 1, amp) - DITHER_AMP_CENTER;
-      // Convert to range: [-2,2] for dither=50, [-4,4] for dither=100
-      const int delta = (bits + DITHER_DESCALE_ROUNDER) >> DITHER_DESCALE;
-      const int v = (int)dst[i] + delta;
-      dst[i] = (v < 0) ? 0 : (v > 255) ? 255u : (uint8_t)v;
-    }
-    dst += bps;
+  uint8_t dither[64];
+  int i;
+  for (i = 0; i < 8 * 8; ++i) {
+    dither[i] = VP8RandomBits2(rg, VP8_DITHER_AMP_BITS + 1, amp);
   }
+  VP8DitherCombine8x8(dither, dst, bps);
 }
 
 static void DitherRow(VP8Decoder* const dec) {
@@ -462,7 +452,7 @@ static int FinishRow(VP8Decoder* const dec, VP8Io* const io) {
     if (dec->alpha_data_ != NULL && y_start < y_end) {
       // TODO(skal): testing presence of alpha with dec->alpha_data_ is not a
       // good idea.
-      io->a = VP8DecompressAlphaRows(dec, y_start, y_end - y_start);
+      io->a = VP8DecompressAlphaRows(dec, io, y_start, y_end - y_start);
       if (io->a == NULL) {
         return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
                            "Could not decode alpha data.");

src/dec/idec.c

@@ -70,7 +70,9 @@ struct WebPIDecoder {
   VP8Io io_;
 
   MemBuffer mem_;          // input memory buffer.
-  WebPDecBuffer output_;   // output buffer (when no external one is supplied)
+  WebPDecBuffer output_;   // output buffer (when no external one is supplied,
+                           // or if the external one has slow-memory)
+  WebPDecBuffer* final_output_;  // Slow-memory output to copy to eventually.
   size_t chunk_size_;      // Compressed VP8/VP8L size extracted from Header.
 
   int last_mb_y_;          // last row reached for intra-mode decoding
@@ -118,9 +120,9 @@ static void DoRemap(WebPIDecoder* const idec, ptrdiff_t offset) {
   if (idec->dec_ != NULL) {
     if (!idec->is_lossless_) {
       VP8Decoder* const dec = (VP8Decoder*)idec->dec_;
-      const int last_part = dec->num_parts_ - 1;
+      const uint32_t last_part = dec->num_parts_minus_one_;
       if (offset != 0) {
-        int p;
+        uint32_t p;
         for (p = 0; p <= last_part; ++p) {
           VP8RemapBitReader(dec->parts_ + p, offset);
         }
@@ -132,7 +134,6 @@ static void DoRemap(WebPIDecoder* const idec, ptrdiff_t offset) {
       }
       {
         const uint8_t* const last_start = dec->parts_[last_part].buf_;
-        assert(last_part >= 0);
         VP8BitReaderSetBuffer(&dec->parts_[last_part], last_start,
                               mem->buf_ + mem->end_ - last_start);
       }
@@ -249,10 +250,16 @@ static VP8StatusCode FinishDecoding(WebPIDecoder* const idec) {
 
   idec->state_ = STATE_DONE;
   if (options != NULL && options->flip) {
-    return WebPFlipBuffer(output);
-  } else {
-    return VP8_STATUS_OK;
+    const VP8StatusCode status = WebPFlipBuffer(output);
+    if (status != VP8_STATUS_OK) return status;
   }
+  if (idec->final_output_ != NULL) {
+    WebPCopyDecBufferPixels(output, idec->final_output_);  // do the slow-copy
+    WebPFreeDecBuffer(&idec->output_);
+    *output = *idec->final_output_;
+    idec->final_output_ = NULL;
+  }
+  return VP8_STATUS_OK;
 }
 
 //------------------------------------------------------------------------------
@@ -457,19 +464,20 @@ static VP8StatusCode DecodeRemaining(WebPIDecoder* const idec) {
     }
     for (; dec->mb_x_ < dec->mb_w_; ++dec->mb_x_) {
       VP8BitReader* const token_br =
-          &dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
+          &dec->parts_[dec->mb_y_ & dec->num_parts_minus_one_];
       MBContext context;
       SaveContext(dec, token_br, &context);
       if (!VP8DecodeMB(dec, token_br)) {
         // We shouldn't fail when MAX_MB data was available
-        if (dec->num_parts_ == 1 && MemDataSize(&idec->mem_) > MAX_MB_SIZE) {
+        if (dec->num_parts_minus_one_ == 0 &&
+            MemDataSize(&idec->mem_) > MAX_MB_SIZE) {
           return IDecError(idec, VP8_STATUS_BITSTREAM_ERROR);
         }
         RestoreContext(&context, dec, token_br);
         return VP8_STATUS_SUSPENDED;
       }
       // Release buffer only if there is only one partition
-      if (dec->num_parts_ == 1) {
+      if (dec->num_parts_minus_one_ == 0) {
         idec->mem_.start_ = token_br->buf_ - idec->mem_.buf_;
         assert(idec->mem_.start_ <= idec->mem_.end_);
       }
@@ -575,9 +583,10 @@ static VP8StatusCode IDecode(WebPIDecoder* idec) {
 }
 
 //------------------------------------------------------------------------------
-// Public functions
+// Internal constructor
 
-WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
+static WebPIDecoder* NewDecoder(WebPDecBuffer* const output_buffer,
+                                const WebPBitstreamFeatures* const features) {
   WebPIDecoder* idec = (WebPIDecoder*)WebPSafeCalloc(1ULL, sizeof(*idec));
   if (idec == NULL) {
     return NULL;
@@ -593,25 +602,46 @@ WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
   VP8InitIo(&idec->io_);
 
   WebPResetDecParams(&idec->params_);
-  idec->params_.output = (output_buffer != NULL) ? output_buffer
-                                                 : &idec->output_;
+  if (output_buffer == NULL || WebPAvoidSlowMemory(output_buffer, features)) {
+    idec->params_.output = &idec->output_;
+    idec->final_output_ = output_buffer;
+    if (output_buffer != NULL) {
+      idec->params_.output->colorspace = output_buffer->colorspace;
+    }
+  } else {
+    idec->params_.output = output_buffer;
+    idec->final_output_ = NULL;
+  }
   WebPInitCustomIo(&idec->params_, &idec->io_);  // Plug the I/O functions.
 
   return idec;
 }
 
+//------------------------------------------------------------------------------
+// Public functions
+
+WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
+  return NewDecoder(output_buffer, NULL);
+}
+
 WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size,
                           WebPDecoderConfig* config) {
   WebPIDecoder* idec;
+  WebPBitstreamFeatures tmp_features;
+  WebPBitstreamFeatures* const features =
+      (config == NULL) ? &tmp_features : &config->input;
+  memset(&tmp_features, 0, sizeof(tmp_features));
 
   // Parse the bitstream's features, if requested:
-  if (data != NULL && data_size > 0 && config != NULL) {
-    if (WebPGetFeatures(data, data_size, &config->input) != VP8_STATUS_OK) {
+  if (data != NULL && data_size > 0) {
+    if (WebPGetFeatures(data, data_size, features) != VP8_STATUS_OK) {
       return NULL;
     }
   }
+
   // Create an instance of the incremental decoder
-  idec = WebPINewDecoder(config ? &config->output : NULL);
+  idec = (config != NULL) ? NewDecoder(&config->output, features)
+                          : NewDecoder(NULL, features);
   if (idec == NULL) {
     return NULL;
   }
@@ -645,11 +675,11 @@ void WebPIDelete(WebPIDecoder* idec) {
 
 WebPIDecoder* WebPINewRGB(WEBP_CSP_MODE mode, uint8_t* output_buffer,
                           size_t output_buffer_size, int output_stride) {
-  const int is_external_memory = (output_buffer != NULL);
+  const int is_external_memory = (output_buffer != NULL) ? 1 : 0;
   WebPIDecoder* idec;
 
   if (mode >= MODE_YUV) return NULL;
-  if (!is_external_memory) {    // Overwrite parameters to sane values.
+  if (is_external_memory == 0) {    // Overwrite parameters to sane values.
     output_buffer_size = 0;
     output_stride = 0;
   } else {  // A buffer was passed. Validate the other params.
@@ -671,11 +701,11 @@ WebPIDecoder* WebPINewYUVA(uint8_t* luma, size_t luma_size, int luma_stride,
                            uint8_t* u, size_t u_size, int u_stride,
                            uint8_t* v, size_t v_size, int v_stride,
                            uint8_t* a, size_t a_size, int a_stride) {
-  const int is_external_memory = (luma != NULL);
+  const int is_external_memory = (luma != NULL) ? 1 : 0;
   WebPIDecoder* idec;
   WEBP_CSP_MODE colorspace;
 
-  if (!is_external_memory) {    // Overwrite parameters to sane values.
+  if (is_external_memory == 0) {    // Overwrite parameters to sane values.
     luma_size = u_size = v_size = a_size = 0;
     luma_stride = u_stride = v_stride = a_stride = 0;
     u = v = a = NULL;
@@ -783,6 +813,9 @@ static const WebPDecBuffer* GetOutputBuffer(const WebPIDecoder* const idec) {
   if (idec->state_ <= STATE_VP8_PARTS0) {
     return NULL;
   }
+  if (idec->final_output_ != NULL) {
+    return NULL;   // not yet slow-copied
+  }
   return idec->params_.output;
 }
 
@@ -792,7 +825,7 @@ const WebPDecBuffer* WebPIDecodedArea(const WebPIDecoder* idec,
   const WebPDecBuffer* const src = GetOutputBuffer(idec);
   if (left != NULL) *left = 0;
   if (top != NULL) *top = 0;
-  if (src) {
+  if (src != NULL) {
     if (width != NULL) *width = src->width;
     if (height != NULL) *height = idec->params_.last_y;
   } else {

src/dec/io.c

@@ -119,6 +119,14 @@ static int EmitFancyRGB(const VP8Io* const io, WebPDecParams* const p) {
 
 //------------------------------------------------------------------------------
 
+static void FillAlphaPlane(uint8_t* dst, int w, int h, int stride) {
+  int j;
+  for (j = 0; j < h; ++j) {
+    memset(dst, 0xff, w * sizeof(*dst));
+    dst += stride;
+  }
+}
+
 static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
                         int expected_num_lines_out) {
   const uint8_t* alpha = io->a;
@@ -137,10 +145,7 @@ static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
     }
   } else if (buf->a != NULL) {
     // the user requested alpha, but there is none, set it to opaque.
-    for (j = 0; j < mb_h; ++j) {
-      memset(dst, 0xff, mb_w * sizeof(*dst));
-      dst += buf->a_stride;
-    }
+    FillAlphaPlane(dst, mb_w, mb_h, buf->a_stride);
   }
   return 0;
 }
@@ -269,8 +274,8 @@ static int EmitRescaledYUV(const VP8Io* const io, WebPDecParams* const p) {
 
 static int EmitRescaledAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
                                 int expected_num_lines_out) {
+  const WebPYUVABuffer* const buf = &p->output->u.YUVA;
   if (io->a != NULL) {
-    const WebPYUVABuffer* const buf = &p->output->u.YUVA;
     uint8_t* dst_y = buf->y + p->last_y * buf->y_stride;
     const uint8_t* src_a = buf->a + p->last_y * buf->a_stride;
     const int num_lines_out = Rescale(io->a, io->width, io->mb_h, &p->scaler_a);
@@ -280,6 +285,11 @@ static int EmitRescaledAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
       WebPMultRows(dst_y, buf->y_stride, src_a, buf->a_stride,
                    p->scaler_a.dst_width, num_lines_out, 1);
     }
+  } else if (buf->a != NULL) {
+    // the user requested alpha, but there is none, set it to opaque.
+    assert(p->last_y + expected_num_lines_out <= io->scaled_height);
+    FillAlphaPlane(buf->a + p->last_y * buf->a_stride,
+                   io->scaled_width, expected_num_lines_out, buf->a_stride);
   }
   return 0;
 }

src/dec/vp8.c

@@ -50,7 +50,7 @@ VP8Decoder* VP8New(void) {
     SetOk(dec);
     WebPGetWorkerInterface()->Init(&dec->worker_);
     dec->ready_ = 0;
-    dec->num_parts_ = 1;
+    dec->num_parts_minus_one_ = 0;
   }
   return dec;
 }
@@ -194,8 +194,8 @@ static VP8StatusCode ParsePartitions(VP8Decoder* const dec,
   size_t last_part;
   size_t p;
 
-  dec->num_parts_ = 1 << VP8GetValue(br, 2);
-  last_part = dec->num_parts_ - 1;
+  dec->num_parts_minus_one_ = (1 << VP8GetValue(br, 2)) - 1;
+  last_part = dec->num_parts_minus_one_;
   if (size < 3 * last_part) {
     // we can't even read the sizes with sz[]! That's a failure.
     return VP8_STATUS_NOT_ENOUGH_DATA;
@@ -303,15 +303,22 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
 
     dec->mb_w_ = (pic_hdr->width_ + 15) >> 4;
     dec->mb_h_ = (pic_hdr->height_ + 15) >> 4;
+
     // Setup default output area (can be later modified during io->setup())
     io->width = pic_hdr->width_;
     io->height = pic_hdr->height_;
-    io->use_scaling  = 0;
+    // IMPORTANT! use some sane dimensions in crop_* and scaled_* fields.
+    // So they can be used interchangeably without always testing for
+    // 'use_cropping'.
     io->use_cropping = 0;
     io->crop_top  = 0;
     io->crop_left = 0;
     io->crop_right  = io->width;
     io->crop_bottom = io->height;
+    io->use_scaling  = 0;
+    io->scaled_width = io->width;
+    io->scaled_height = io->height;
+
     io->mb_w = io->width;   // sanity check
     io->mb_h = io->height;  // ditto
 
@@ -579,7 +586,7 @@ static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
   for (dec->mb_y_ = 0; dec->mb_y_ < dec->br_mb_y_; ++dec->mb_y_) {
     // Parse bitstream for this row.
     VP8BitReader* const token_br =
-        &dec->parts_[dec->mb_y_ & (dec->num_parts_ - 1)];
+        &dec->parts_[dec->mb_y_ & dec->num_parts_minus_one_];
     if (!VP8ParseIntraModeRow(&dec->br_, dec)) {
       return VP8SetError(dec, VP8_STATUS_NOT_ENOUGH_DATA,
                          "Premature end-of-partition0 encountered.");
@@ -649,8 +656,7 @@ void VP8Clear(VP8Decoder* const dec) {
     return;
   }
   WebPGetWorkerInterface()->End(&dec->worker_);
-  ALPHDelete(dec->alph_dec_);
-  dec->alph_dec_ = NULL;
+  WebPDeallocateAlphaMemory(dec);
   WebPSafeFree(dec->mem_);
   dec->mem_ = NULL;
   dec->mem_size_ = 0;
@@ -659,4 +665,3 @@ void VP8Clear(VP8Decoder* const dec) {
 }
 
 //------------------------------------------------------------------------------
-

src/dec/vp8i.h

@@ -32,7 +32,7 @@ extern "C" {
 // version numbers
 #define DEC_MAJ_VERSION 0
 #define DEC_MIN_VERSION 5
-#define DEC_REV_VERSION 0
+#define DEC_REV_VERSION 2
 
 // YUV-cache parameters. Cache is 32-bytes wide (= one cacheline).
 // Constraints are: We need to store one 16x16 block of luma samples (y),
@@ -209,8 +209,8 @@ struct VP8Decoder {
   int tl_mb_x_, tl_mb_y_;  // top-left MB that must be in-loop filtered
   int br_mb_x_, br_mb_y_;  // last bottom-right MB that must be decoded
 
-  // number of partitions.
-  int num_parts_;
+  // number of partitions minus one.
+  uint32_t num_parts_minus_one_;
   // per-partition boolean decoders.
   VP8BitReader parts_[MAX_NUM_PARTITIONS];
 
@@ -258,9 +258,11 @@ struct VP8Decoder {
   struct ALPHDecoder* alph_dec_;  // alpha-plane decoder object
   const uint8_t* alpha_data_;     // compressed alpha data (if present)
   size_t alpha_data_size_;
-  int is_alpha_decoded_;  // true if alpha_data_ is decoded in alpha_plane_
-  uint8_t* alpha_plane_;  // output. Persistent, contains the whole data.
-  int alpha_dithering_;   // derived from decoding options (0=off, 100=full).
+  int is_alpha_decoded_;      // true if alpha_data_ is decoded in alpha_plane_
+  uint8_t* alpha_plane_mem_;  // memory allocated for alpha_plane_
+  uint8_t* alpha_plane_;      // output. Persistent, contains the whole data.
+  const uint8_t* alpha_prev_line_;  // last decoded alpha row (or NULL)
+  int alpha_dithering_;       // derived from decoding options (0=off, 100=full)
 };
 
 //------------------------------------------------------------------------------
@@ -306,6 +308,7 @@ int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br);
 
 // in alpha.c
 const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
+                                      const VP8Io* const io,
                                       int row, int num_rows);
 
 //------------------------------------------------------------------------------

src/dec/vp8l.c

@@ -252,11 +252,11 @@ 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;
   }
 
@@ -276,7 +276,7 @@ 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) {
@@ -299,6 +299,7 @@ static int ReadHuffmanCodeLengths(
   ok = 1;
 
  End:
+  VP8LHuffmanTablesDeallocate(&tables);
   if (!ok) dec->status_ = VP8_STATUS_BITSTREAM_ERROR;
   return ok;
 }
@@ -306,7 +307,8 @@ static int ReadHuffmanCodeLengths(
 // '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_;
@@ -361,12 +363,18 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
   VP8LMetadata* const hdr = &dec->hdr_;
   uint32_t* huffman_image = NULL;
   HTreeGroup* htree_groups = NULL;
-  HuffmanCode* huffman_tables = NULL;
-  HuffmanCode* next = 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.
@@ -383,10 +391,36 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
       // The huffman data is stored in red and green bytes.
       const int group = (huffman_image[i] >> 8) & 0xffff;
       huffman_image[i] = group;
-      if (group >= num_htree_groups) {
-        num_htree_groups = group + 1;
+      if (group >= num_htree_groups_max) {
+        num_htree_groups_max = group + 1;
       }
     }
+    // Check the validity of num_htree_groups_max. If it seems too big, use a
+    // smaller value for later. This will prevent big memory allocations to end
+    // up with a bad bitstream anyway.
+    // The value of 1000 is totally arbitrary. We know that num_htree_groups_max
+    // is smaller than (1 << 16) and should be smaller than the number of pixels
+    // (though the format allows it to be bigger).
+    if (num_htree_groups_max > 1000 || num_htree_groups_max > xsize * ysize) {
+      // Create a mapping from the used indices to the minimal set of used
+      // values [0, num_htree_groups)
+      mapping = (int*)WebPSafeMalloc(num_htree_groups_max, sizeof(*mapping));
+      if (mapping == NULL) {
+        dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
+        goto Error;
+      }
+      // -1 means a value is unmapped, and therefore unused in the Huffman
+      // image.
+      memset(mapping, 0xff, num_htree_groups_max * sizeof(*mapping));
+      for (num_htree_groups = 0, i = 0; i < huffman_pixs; ++i) {
+        // Get the current mapping for the group and remap the Huffman image.
+        int* const mapped_group = &mapping[huffman_image[i]];
+        if (*mapped_group == -1) *mapped_group = num_htree_groups++;
+        huffman_image[i] = *mapped_group;
+      }
+    } else {
+      num_htree_groups = num_htree_groups_max;
+    }
   }
 
   if (br->eos_) goto Error;
@@ -402,83 +436,99 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
     }
   }
 
-  huffman_tables = (HuffmanCode*)WebPSafeMalloc(num_htree_groups * table_size,
-                                                sizeof(*huffman_tables));
   htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
   code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
                                       sizeof(*code_lengths));
 
-  if (htree_groups == NULL || code_lengths == NULL || huffman_tables == NULL) {
+  if (htree_groups == NULL || code_lengths == NULL ||
+      !VP8LHuffmanTablesAllocate(num_htree_groups * table_size,
+                                 huffman_tables)) {
     dec->status_ = VP8_STATUS_OUT_OF_MEMORY;
     goto Error;
   }
 
-  next = huffman_tables;
-  for (i = 0; i < num_htree_groups; ++i) {
-    HTreeGroup* const htree_group = &htree_groups[i];
-    HuffmanCode** const htrees = htree_group->htrees;
-    int size;
-    int total_size = 0;
-    int is_trivial_literal = 1;
-    int max_bits = 0;
-    for (j = 0; j < HUFFMAN_CODES_PER_META_CODE; ++j) {
-      int alphabet_size = kAlphabetSize[j];
-      htrees[j] = next;
-      if (j == 0 && color_cache_bits > 0) {
-        alphabet_size += 1 << color_cache_bits;
-      }
-      size = ReadHuffmanCode(alphabet_size, dec, code_lengths, next);
-      if (size == 0) {
-        goto Error;
-      }
-      if (is_trivial_literal && kLiteralMap[j] == 1) {
-        is_trivial_literal = (next->bits == 0);
-      }
-      total_size += next->bits;
-      next += size;
-      if (j <= ALPHA) {
-        int local_max_bits = code_lengths[0];
-        int k;
-        for (k = 1; k < alphabet_size; ++k) {
-          if (code_lengths[k] > local_max_bits) {
-            local_max_bits = code_lengths[k];
-          }
+  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.
+    if (mapping != NULL && mapping[i] == -1) {
+      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);
+        }
+        // Passing in NULL so that nothing gets filled.
+        if (!ReadHuffmanCode(alphabet_size, dec, code_lengths, NULL)) {
+          goto Error;
         }
-        max_bits += local_max_bits;
       }
-    }
-    htree_group->is_trivial_literal = is_trivial_literal;
-    htree_group->is_trivial_code = 0;
-    if (is_trivial_literal) {
-      const int red = htrees[RED][0].value;
-      const int blue = htrees[BLUE][0].value;
-      const int alpha = htrees[ALPHA][0].value;
-      htree_group->literal_arb =
-          ((uint32_t)alpha << 24) | (red << 16) | blue;
-      if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) {
-        htree_group->is_trivial_code = 1;
-        htree_group->literal_arb |= htrees[GREEN][0].value << 8;
+    } else {
+      HTreeGroup* const htree_group =
+          &htree_groups[(mapping == NULL) ? i : mapping[i]];
+      HuffmanCode** const htrees = htree_group->htrees;
+      int size;
+      int total_size = 0;
+      int is_trivial_literal = 1;
+      int max_bits = 0;
+      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);
+        }
+        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 = (htrees[j]->bits == 0);
+        }
+        total_size += htrees[j]->bits;
+        huffman_tables->curr_segment->curr_table += size;
+        if (j <= ALPHA) {
+          int local_max_bits = code_lengths[0];
+          int k;
+          for (k = 1; k < alphabet_size; ++k) {
+            if (code_lengths[k] > local_max_bits) {
+              local_max_bits = code_lengths[k];
+            }
+          }
+          max_bits += local_max_bits;
+        }
       }
+      htree_group->is_trivial_literal = is_trivial_literal;
+      htree_group->is_trivial_code = 0;
+      if (is_trivial_literal) {
+        const int red = htrees[RED][0].value;
+        const int blue = htrees[BLUE][0].value;
+        const int alpha = htrees[ALPHA][0].value;
+        htree_group->literal_arb = ((uint32_t)alpha << 24) | (red << 16) | blue;
+        if (total_size == 0 && htrees[GREEN][0].value < NUM_LITERAL_CODES) {
+          htree_group->is_trivial_code = 1;
+          htree_group->literal_arb |= htrees[GREEN][0].value << 8;
+        }
+      }
+      htree_group->use_packed_table =
+          !htree_group->is_trivial_code && (max_bits < HUFFMAN_PACKED_BITS);
+      if (htree_group->use_packed_table) BuildPackedTable(htree_group);
     }
-    htree_group->use_packed_table = !htree_group->is_trivial_code &&
-                                    (max_bits < HUFFMAN_PACKED_BITS);
-    if (htree_group->use_packed_table) BuildPackedTable(htree_group);
   }
-  WebPSafeFree(code_lengths);
+  ok = 1;
 
-  // All OK. Finalize pointers and return.
+  // 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;
-  return 1;
 
  Error:
   WebPSafeFree(code_lengths);
-  WebPSafeFree(huffman_image);
-  WebPSafeFree(huffman_tables);
-  VP8LHtreeGroupsFree(htree_groups);
-  return 0;
+  WebPSafeFree(mapping);
+  if (!ok) {
+    WebPSafeFree(huffman_image);
+    VP8LHuffmanTablesDeallocate(huffman_tables);
+    VP8LHtreeGroupsFree(htree_groups);
+  }
+  return ok;
 }
 
 //------------------------------------------------------------------------------
@@ -714,34 +764,22 @@ static void ApplyInverseTransforms(VP8LDecoder* const dec, int num_rows,
   }
 }
 
-// Special method for paletted alpha data.
-static void ApplyInverseTransformsAlpha(VP8LDecoder* const dec, int num_rows,
-                                        const uint8_t* const rows) {
-  const int start_row = dec->last_row_;
-  const int end_row = start_row + num_rows;
-  const uint8_t* rows_in = rows;
-  uint8_t* rows_out = (uint8_t*)dec->io_->opaque + dec->io_->width * start_row;
-  VP8LTransform* const transform = &dec->transforms_[0];
-  assert(dec->next_transform_ == 1);
-  assert(transform->type_ == COLOR_INDEXING_TRANSFORM);
-  VP8LColorIndexInverseTransformAlpha(transform, start_row, end_row, rows_in,
-                                      rows_out);
-}
-
 // Processes (transforms, scales & color-converts) the rows decoded after the
 // last call.
 static void ProcessRows(VP8LDecoder* const dec, int row) {
   const uint32_t* const rows = dec->pixels_ + dec->width_ * dec->last_row_;
   const int num_rows = row - dec->last_row_;
 
-  if (num_rows <= 0) return;  // Nothing to be done.
-  ApplyInverseTransforms(dec, num_rows, rows);
-
-  // Emit output.
-  {
+  assert(row <= dec->io_->crop_bottom);
+  // We can't process more than NUM_ARGB_CACHE_ROWS at a time (that's the size
+  // of argb_cache_), but we currently don't need more than that.
+  assert(num_rows <= NUM_ARGB_CACHE_ROWS);
+  if (num_rows > 0) {    // Emit output.
     VP8Io* const io = dec->io_;
     uint8_t* rows_data = (uint8_t*)dec->argb_cache_;
     const int in_stride = io->width * sizeof(uint32_t);  // in unit of RGBA
+
+    ApplyInverseTransforms(dec, num_rows, rows);
     if (!SetCropWindow(io, dec->last_row_, row, &rows_data, in_stride)) {
       // Nothing to output (this time).
     } else {
@@ -786,14 +824,46 @@ static int Is8bOptimizable(const VP8LMetadata* const hdr) {
   return 1;
 }
 
-static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int row) {
-  const int num_rows = row - dec->last_row_;
-  const uint8_t* const in =
-      (uint8_t*)dec->pixels_ + dec->width_ * dec->last_row_;
-  if (num_rows > 0) {
-    ApplyInverseTransformsAlpha(dec, num_rows, in);
+static void AlphaApplyFilter(ALPHDecoder* const alph_dec,
+                             int first_row, int last_row,
+                             uint8_t* out, int stride) {
+  if (alph_dec->filter_ != WEBP_FILTER_NONE) {
+    int y;
+    const uint8_t* prev_line = alph_dec->prev_line_;
+    assert(WebPUnfilters[alph_dec->filter_] != NULL);
+    for (y = first_row; y < last_row; ++y) {
+      WebPUnfilters[alph_dec->filter_](prev_line, out, out, stride);
+      prev_line = out;
+      out += stride;
+    }
+    alph_dec->prev_line_ = prev_line;
   }
-  dec->last_row_ = dec->last_out_row_ = row;
+}
+
+static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int last_row) {
+  // For vertical and gradient filtering, we need to decode the part above the
+  // crop_top row, in order to have the correct spatial predictors.
+  ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
+  const int top_row =
+      (alph_dec->filter_ == WEBP_FILTER_NONE ||
+       alph_dec->filter_ == WEBP_FILTER_HORIZONTAL) ? dec->io_->crop_top
+                                                    : dec->last_row_;
+  const int first_row = (dec->last_row_ < top_row) ? top_row : dec->last_row_;
+  assert(last_row <= dec->io_->crop_bottom);
+  if (last_row > first_row) {
+    // Special method for paletted alpha data. We only process the cropped area.
+    const int width = dec->io_->width;
+    uint8_t* out = alph_dec->output_ + width * first_row;
+    const uint8_t* const in =
+      (uint8_t*)dec->pixels_ + dec->width_ * first_row;
+    VP8LTransform* const transform = &dec->transforms_[0];
+    assert(dec->next_transform_ == 1);
+    assert(transform->type_ == COLOR_INDEXING_TRANSFORM);
+    VP8LColorIndexInverseTransformAlpha(transform, first_row, last_row,
+                                        in, out);
+    AlphaApplyFilter(alph_dec, first_row, last_row, out, width);
+  }
+  dec->last_row_ = dec->last_out_row_ = last_row;
 }
 
 //------------------------------------------------------------------------------
@@ -922,14 +992,14 @@ static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
   int col = dec->last_pixel_ % width;
   VP8LBitReader* const br = &dec->br_;
   VP8LMetadata* const hdr = &dec->hdr_;
-  const HTreeGroup* htree_group = GetHtreeGroupForPos(hdr, col, row);
   int pos = dec->last_pixel_;         // current position
   const int end = width * height;     // End of data
   const int last = width * last_row;  // Last pixel to decode
   const int len_code_limit = NUM_LITERAL_CODES + NUM_LENGTH_CODES;
   const int mask = hdr->huffman_mask_;
-  assert(htree_group != NULL);
-  assert(pos < end);
+  const HTreeGroup* htree_group =
+      (pos < last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
+  assert(pos <= end);
   assert(last_row <= height);
   assert(Is8bOptimizable(hdr));
 
@@ -939,6 +1009,7 @@ static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
     if ((col & mask) == 0) {
       htree_group = GetHtreeGroupForPos(hdr, col, row);
     }
+    assert(htree_group != NULL);
     VP8LFillBitWindow(br);
     code = ReadSymbol(htree_group->htrees[GREEN], br);
     if (code < NUM_LITERAL_CODES) {  // Literal
@@ -948,7 +1019,7 @@ static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
       if (col >= width) {
         col = 0;
         ++row;
-        if (row % NUM_ARGB_CACHE_ROWS == 0) {
+        if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
           ExtractPalettedAlphaRows(dec, row);
         }
       }
@@ -971,7 +1042,7 @@ static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
       while (col >= width) {
         col -= width;
         ++row;
-        if (row % NUM_ARGB_CACHE_ROWS == 0) {
+        if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
           ExtractPalettedAlphaRows(dec, row);
         }
       }
@@ -985,7 +1056,7 @@ static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data,
     assert(br->eos_ == VP8LIsEndOfStream(br));
   }
   // Process the remaining rows corresponding to last row-block.
-  ExtractPalettedAlphaRows(dec, row);
+  ExtractPalettedAlphaRows(dec, row > last_row ? last_row : row);
 
  End:
   if (!ok || (br->eos_ && pos < end)) {
@@ -1025,7 +1096,6 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
   int col = dec->last_pixel_ % width;
   VP8LBitReader* const br = &dec->br_;
   VP8LMetadata* const hdr = &dec->hdr_;
-  HTreeGroup* htree_group = GetHtreeGroupForPos(hdr, col, row);
   uint32_t* src = data + dec->last_pixel_;
   uint32_t* last_cached = src;
   uint32_t* const src_end = data + width * height;     // End of data
@@ -1036,8 +1106,9 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
   VP8LColorCache* const color_cache =
       (hdr->color_cache_size_ > 0) ? &hdr->color_cache_ : NULL;
   const int mask = hdr->huffman_mask_;
-  assert(htree_group != NULL);
-  assert(src < src_end);
+  const HTreeGroup* htree_group =
+      (src < src_last) ? GetHtreeGroupForPos(hdr, col, row) : NULL;
+  assert(dec->last_row_ < last_row);
   assert(src_last <= src_end);
 
   while (src < src_last) {
@@ -1049,7 +1120,10 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
     // Only update when changing tile. Note we could use this test:
     // if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed
     // but that's actually slower and needs storing the previous col/row.
-    if ((col & mask) == 0) htree_group = GetHtreeGroupForPos(hdr, col, row);
+    if ((col & mask) == 0) {
+      htree_group = GetHtreeGroupForPos(hdr, col, row);
+    }
+    assert(htree_group != NULL);
     if (htree_group->is_trivial_code) {
       *src = htree_group->literal_arb;
       goto AdvanceByOne;
@@ -1080,8 +1154,10 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
       if (col >= width) {
         col = 0;
         ++row;
-        if ((row % NUM_ARGB_CACHE_ROWS == 0) && (process_func != NULL)) {
-          process_func(dec, row);
+        if (process_func != NULL) {
+          if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
+            process_func(dec, row);
+          }
         }
         if (color_cache != NULL) {
           while (last_cached < src) {
@@ -1108,8 +1184,10 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
       while (col >= width) {
         col -= width;
         ++row;
-        if ((row % NUM_ARGB_CACHE_ROWS == 0) && (process_func != NULL)) {
-          process_func(dec, row);
+        if (process_func != NULL) {
+          if (row <= last_row && (row % NUM_ARGB_CACHE_ROWS == 0)) {
+            process_func(dec, row);
+          }
         }
       }
       // Because of the check done above (before 'src' was incremented by
@@ -1135,12 +1213,24 @@ static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data,
     assert(br->eos_ == VP8LIsEndOfStream(br));
   }
 
-  if (dec->incremental_ && br->eos_ && src < src_end) {
+  br->eos_ = VP8LIsEndOfStream(br);
+  // 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);
+      process_func(dec, row > last_row ? last_row : row);
     }
     dec->status_ = VP8_STATUS_OK;
     dec->last_pixel_ = (int)(src - data);  // end-of-scan marker
@@ -1255,7 +1345,7 @@ 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_);
@@ -1438,46 +1528,51 @@ static int AllocateInternalBuffers8b(VP8LDecoder* const dec) {
 //------------------------------------------------------------------------------
 
 // Special row-processing that only stores the alpha data.
-static void ExtractAlphaRows(VP8LDecoder* const dec, int row) {
-  const int num_rows = row - dec->last_row_;
-  const uint32_t* const in = dec->pixels_ + dec->width_ * dec->last_row_;
+static void ExtractAlphaRows(VP8LDecoder* const dec, int last_row) {
+  int cur_row = dec->last_row_;
+  int num_rows = last_row - cur_row;
+  const uint32_t* in = dec->pixels_ + dec->width_ * cur_row;
 
-  if (num_rows <= 0) return;  // Nothing to be done.
-  ApplyInverseTransforms(dec, num_rows, in);
-
-  // Extract alpha (which is stored in the green plane).
-  {
+  assert(last_row <= dec->io_->crop_bottom);
+  while (num_rows > 0) {
+    const int num_rows_to_process =
+        (num_rows > NUM_ARGB_CACHE_ROWS) ? NUM_ARGB_CACHE_ROWS : num_rows;
+    // Extract alpha (which is stored in the green plane).
+    ALPHDecoder* const alph_dec = (ALPHDecoder*)dec->io_->opaque;
+    uint8_t* const output = alph_dec->output_;
     const int width = dec->io_->width;      // the final width (!= dec->width_)
-    const int cache_pixs = width * num_rows;
-    uint8_t* const dst = (uint8_t*)dec->io_->opaque + width * dec->last_row_;
+    const int cache_pixs = width * num_rows_to_process;
+    uint8_t* const dst = output + width * cur_row;
     const uint32_t* const src = dec->argb_cache_;
     int i;
+    ApplyInverseTransforms(dec, num_rows_to_process, in);
     for (i = 0; i < cache_pixs; ++i) dst[i] = (src[i] >> 8) & 0xff;
+    AlphaApplyFilter(alph_dec,
+                     cur_row, cur_row + num_rows_to_process, dst, width);
+    num_rows -= num_rows_to_process;
+    in += num_rows_to_process * dec->width_;
+    cur_row += num_rows_to_process;
   }
-  dec->last_row_ = dec->last_out_row_ = row;
+  assert(cur_row == last_row);
+  dec->last_row_ = dec->last_out_row_ = last_row;
 }
 
 int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
-                          const uint8_t* const data, size_t data_size,
-                          uint8_t* const output) {
+                          const uint8_t* const data, size_t data_size) {
   int ok = 0;
-  VP8LDecoder* dec;
-  VP8Io* io;
+  VP8LDecoder* dec = VP8LNew();
+
+  if (dec == NULL) return 0;
+
   assert(alph_dec != NULL);
-  alph_dec->vp8l_dec_ = VP8LNew();
-  if (alph_dec->vp8l_dec_ == NULL) return 0;
-  dec = alph_dec->vp8l_dec_;
+  alph_dec->vp8l_dec_ = dec;
 
   dec->width_ = alph_dec->width_;
   dec->height_ = alph_dec->height_;
   dec->io_ = &alph_dec->io_;
-  io = dec->io_;
-
-  VP8InitIo(io);
-  WebPInitCustomIo(NULL, io);  // Just a sanity Init. io won't be used.
-  io->opaque = output;
-  io->width = alph_dec->width_;
-  io->height = alph_dec->height_;
+  dec->io_->opaque = alph_dec;
+  dec->io_->width = alph_dec->width_;
+  dec->io_->height = alph_dec->height_;
 
   dec->status_ = VP8_STATUS_OK;
   VP8LInitBitReader(&dec->br_, data, data_size);
@@ -1492,11 +1587,11 @@ int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec,
   if (dec->next_transform_ == 1 &&
       dec->transforms_[0].type_ == COLOR_INDEXING_TRANSFORM &&
       Is8bOptimizable(&dec->hdr_)) {
-    alph_dec->use_8b_decode = 1;
+    alph_dec->use_8b_decode_ = 1;
     ok = AllocateInternalBuffers8b(dec);
   } else {
     // Allocate internal buffers (note that dec->width_ may have changed here).
-    alph_dec->use_8b_decode = 0;
+    alph_dec->use_8b_decode_ = 0;
     ok = AllocateInternalBuffers32b(dec, alph_dec->width_);
   }
 
@@ -1515,12 +1610,12 @@ int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) {
   assert(dec != NULL);
   assert(last_row <= dec->height_);
 
-  if (dec->last_pixel_ == dec->width_ * dec->height_) {
+  if (dec->last_row_ >= last_row) {
     return 1;  // done
   }
 
   // Decode (with special row processing).
-  return alph_dec->use_8b_decode ?
+  return alph_dec->use_8b_decode_ ?
       DecodeAlphaData(dec, (uint8_t*)dec->pixels_, dec->width_, dec->height_,
                       last_row) :
       DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
@@ -1565,7 +1660,7 @@ int VP8LDecodeImage(VP8LDecoder* const dec) {
   // Sanity checks.
   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);
 
@@ -1611,7 +1706,7 @@ int VP8LDecodeImage(VP8LDecoder* const dec) {
 
   // Decode.
   if (!DecodeImageData(dec, dec->pixels_, dec->width_, dec->height_,
-                       dec->height_, ProcessRows)) {
+                       io->crop_bottom, ProcessRows)) {
     goto Err;
   }
 

src/dec/vp8li.h

@@ -51,7 +51,7 @@ typedef struct {
   uint32_t       *huffman_image_;
   int             num_htree_groups_;
   HTreeGroup     *htree_groups_;
-  HuffmanCode    *huffman_tables_;
+  HuffmanTables   huffman_tables_;
 } VP8LMetadata;
 
 typedef struct VP8LDecoder VP8LDecoder;
@@ -100,8 +100,7 @@ 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,
-                          uint8_t* const output);
+                          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

src/dec/webp.c

@@ -415,7 +415,8 @@ static VP8StatusCode ParseHeadersInternal(const uint8_t* data,
 }
 
 VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
-  VP8StatusCode status;
+  // status is marked volatile as a workaround for a clang-3.8 (aarch64) bug
+  volatile VP8StatusCode status;
   int has_animation = 0;
   assert(headers != NULL);
   // fill out headers, ignore width/height/has_alpha.
@@ -512,10 +513,12 @@ static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
 
   if (status != VP8_STATUS_OK) {
     WebPFreeDecBuffer(params->output);
-  }
-
-  if (params->options != NULL && params->options->flip) {
-    status = WebPFlipBuffer(params->output);
+  } else {
+    if (params->options != NULL && params->options->flip) {
+      // This restores the original stride values if options->flip was used
+      // during the call to WebPAllocateDecBuffer above.
+      status = WebPFlipBuffer(params->output);
+    }
   }
   return status;
 }
@@ -758,9 +761,24 @@ VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
   }
 
   WebPResetDecParams(&params);
-  params.output = &config->output;
   params.options = &config->options;
-  status = DecodeInto(data, data_size, &params);
+  params.output = &config->output;
+  if (WebPAvoidSlowMemory(params.output, &config->input)) {
+    // decoding to slow memory: use a temporary in-mem buffer to decode into.
+    WebPDecBuffer in_mem_buffer;
+    WebPInitDecBuffer(&in_mem_buffer);
+    in_mem_buffer.colorspace = config->output.colorspace;
+    in_mem_buffer.width = config->input.width;
+    in_mem_buffer.height = config->input.height;
+    params.output = &in_mem_buffer;
+    status = DecodeInto(data, data_size, &params);
+    if (status == VP8_STATUS_OK) {  // do the slow-copy
+      status = WebPCopyDecBufferPixels(&in_mem_buffer, &config->output);
+    }
+    WebPFreeDecBuffer(&in_mem_buffer);
+  } else {
+    status = DecodeInto(data, data_size, &params);
+  }
 
   return status;
 }
@@ -809,7 +827,7 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
   }
 
   // Filter
-  io->bypass_filtering = options && options->bypass_filtering;
+  io->bypass_filtering = (options != NULL) && options->bypass_filtering;
 
   // Fancy upsampler
 #ifdef FANCY_UPSAMPLING
@@ -826,4 +844,3 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
 }
 
 //------------------------------------------------------------------------------
-

src/dec/webpi.h

@@ -45,11 +45,20 @@ struct WebPDecParams {
   OutputFunc emit;               // output RGB or YUV samples
   OutputAlphaFunc emit_alpha;    // output alpha channel
   OutputRowFunc emit_alpha_row;  // output one line of rescaled alpha values
+
+  WebPDecBuffer* final_output;   // In case the user supplied a slow-memory
+                                 // output, we decode image in temporary buffer
+                                 // (this::output) and copy it here.
+  WebPDecBuffer tmp_buffer;      // this::output will point to this one in case
+                                 // of slow memory.
 };
 
 // Should be called first, before any use of the WebPDecParams object.
 void WebPResetDecParams(WebPDecParams* const params);
 
+// Delete all memory (after an error occurred, for instance)
+void WebPFreeDecParams(WebPDecParams* const params);
+
 //------------------------------------------------------------------------------
 // Header parsing helpers
 
@@ -107,13 +116,23 @@ VP8StatusCode WebPAllocateDecBuffer(int width, int height,
 VP8StatusCode WebPFlipBuffer(WebPDecBuffer* const buffer);
 
 // Copy 'src' into 'dst' buffer, making sure 'dst' is not marked as owner of the
-// memory (still held by 'src').
+// memory (still held by 'src'). No pixels are copied.
 void WebPCopyDecBuffer(const WebPDecBuffer* const src,
                        WebPDecBuffer* const dst);
 
 // Copy and transfer ownership from src to dst (beware of parameter order!)
 void WebPGrabDecBuffer(WebPDecBuffer* const src, WebPDecBuffer* const dst);
 
+// Copy pixels from 'src' into a *preallocated* 'dst' buffer. Returns
+// VP8_STATUS_INVALID_PARAM if the 'dst' is not set up correctly for the copy.
+VP8StatusCode WebPCopyDecBufferPixels(const WebPDecBuffer* const src,
+                                      WebPDecBuffer* const dst);
+
+// Returns true if decoding will be slow with the current configuration
+// and bitstream features.
+int WebPAvoidSlowMemory(const WebPDecBuffer* const output,
+                        const WebPBitstreamFeatures* const features);
+
 //------------------------------------------------------------------------------
 
 #ifdef __cplusplus

src/demux/Makefile.am

@@ -9,6 +9,6 @@ libwebpdemuxinclude_HEADERS += ../webp/mux_types.h
 libwebpdemuxinclude_HEADERS += ../webp/types.h
 
 libwebpdemux_la_LIBADD = ../libwebp.la
-libwebpdemux_la_LDFLAGS = -no-undefined -version-info 2:0:0
+libwebpdemux_la_LDFLAGS = -no-undefined -version-info 2:1:0
 libwebpdemuxincludedir = $(includedir)/webp
 pkgconfig_DATA = libwebpdemux.pc

src/demux/anim_decode.c

@@ -112,18 +112,15 @@ WebPAnimDecoder* WebPAnimDecoderNewInternal(
   dec->info_.bgcolor = WebPDemuxGetI(dec->demux_, WEBP_FF_BACKGROUND_COLOR);
   dec->info_.frame_count = WebPDemuxGetI(dec->demux_, WEBP_FF_FRAME_COUNT);
 
-  {
-    const int canvas_bytes =
-        dec->info_.canvas_width * NUM_CHANNELS * dec->info_.canvas_height;
-    // Note: calloc() because we fill frame with zeroes as well.
-    dec->curr_frame_ = WebPSafeCalloc(1ULL, canvas_bytes);
-    if (dec->curr_frame_ == NULL) goto Error;
-    dec->prev_frame_disposed_ = WebPSafeCalloc(1ULL, canvas_bytes);
-    if (dec->prev_frame_disposed_ == NULL) goto Error;
-  }
+  // Note: calloc() because we fill frame with zeroes as well.
+  dec->curr_frame_ = (uint8_t*)WebPSafeCalloc(
+      dec->info_.canvas_width * NUM_CHANNELS, dec->info_.canvas_height);
+  if (dec->curr_frame_ == NULL) goto Error;
+  dec->prev_frame_disposed_ = (uint8_t*)WebPSafeCalloc(
+      dec->info_.canvas_width * NUM_CHANNELS, dec->info_.canvas_height);
+  if (dec->prev_frame_disposed_ == NULL) goto Error;
 
   WebPAnimDecoderReset(dec);
-
   return dec;
 
  Error:
@@ -144,9 +141,13 @@ static int IsFullFrame(int width, int height, int canvas_width,
 }
 
 // Clear the canvas to transparent.
-static void ZeroFillCanvas(uint8_t* buf, uint32_t canvas_width,
-                           uint32_t canvas_height) {
-  memset(buf, 0, canvas_width * NUM_CHANNELS * canvas_height);
+static int ZeroFillCanvas(uint8_t* buf, uint32_t canvas_width,
+                          uint32_t canvas_height) {
+  const uint64_t size =
+      (uint64_t)canvas_width * canvas_height * NUM_CHANNELS * sizeof(*buf);
+  if (size != (size_t)size) return 0;
+  memset(buf, 0, (size_t)size);
+  return 1;
 }
 
 // Clear given frame rectangle to transparent.
@@ -162,10 +163,13 @@ static void ZeroFillFrameRect(uint8_t* buf, int buf_stride, int x_offset,
 }
 
 // Copy width * height pixels from 'src' to 'dst'.
-static void CopyCanvas(const uint8_t* src, uint8_t* dst,
-                       uint32_t width, uint32_t height) {
+static int CopyCanvas(const uint8_t* src, uint8_t* dst,
+                      uint32_t width, uint32_t height) {
+  const uint64_t size = (uint64_t)width * height * NUM_CHANNELS;
+  if (size != (size_t)size) return 0;
   assert(src != NULL && dst != NULL);
-  memcpy(dst, src, width * NUM_CHANNELS * height);
+  memcpy(dst, src, (size_t)size);
+  return 1;
 }
 
 // Returns true if the current frame is a key-frame.
@@ -328,9 +332,14 @@ int WebPAnimDecoderGetNext(WebPAnimDecoder* dec,
   is_key_frame = IsKeyFrame(&iter, &dec->prev_iter_,
                             dec->prev_frame_was_keyframe_, width, height);
   if (is_key_frame) {
-    ZeroFillCanvas(dec->curr_frame_, width, height);
+    if (!ZeroFillCanvas(dec->curr_frame_, width, height)) {
+      goto Error;
+    }
   } else {
-    CopyCanvas(dec->prev_frame_disposed_, dec->curr_frame_, width, height);
+    if (!CopyCanvas(dec->prev_frame_disposed_, dec->curr_frame_,
+                    width, height)) {
+      goto Error;
+    }
   }
 
   // Decode.
@@ -393,6 +402,7 @@ int WebPAnimDecoderGetNext(WebPAnimDecoder* dec,
 
   // Update info of the previous frame and dispose it for the next iteration.
   dec->prev_frame_timestamp_ = timestamp;
+  WebPDemuxReleaseIterator(&dec->prev_iter_);
   dec->prev_iter_ = iter;
   dec->prev_frame_was_keyframe_ = is_key_frame;
   CopyCanvas(dec->curr_frame_, dec->prev_frame_disposed_, width, height);
@@ -421,6 +431,7 @@ int WebPAnimDecoderHasMoreFrames(const WebPAnimDecoder* dec) {
 void WebPAnimDecoderReset(WebPAnimDecoder* dec) {
   if (dec != NULL) {
     dec->prev_frame_timestamp_ = 0;
+    WebPDemuxReleaseIterator(&dec->prev_iter_);
     memset(&dec->prev_iter_, 0, sizeof(dec->prev_iter_));
     dec->prev_frame_was_keyframe_ = 0;
     dec->next_frame_ = 1;
@@ -434,6 +445,7 @@ const WebPDemuxer* WebPAnimDecoderGetDemuxer(const WebPAnimDecoder* dec) {
 
 void WebPAnimDecoderDelete(WebPAnimDecoder* dec) {
   if (dec != NULL) {
+    WebPDemuxReleaseIterator(&dec->prev_iter_);
     WebPDemuxDelete(dec->demux_);
     WebPSafeFree(dec->curr_frame_);
     WebPSafeFree(dec->prev_frame_disposed_);

src/demux/demux.c

@@ -25,7 +25,7 @@
 
 #define DMUX_MAJ_VERSION 0
 #define DMUX_MIN_VERSION 3
-#define DMUX_REV_VERSION 0
+#define DMUX_REV_VERSION 1
 
 typedef struct {
   size_t start_;        // start location of the data

src/dsp/Makefile.am

@@ -1,6 +1,8 @@
 noinst_LTLIBRARIES = libwebpdsp.la libwebpdsp_avx2.la
 noinst_LTLIBRARIES += libwebpdsp_sse2.la libwebpdspdecode_sse2.la
 noinst_LTLIBRARIES += libwebpdsp_sse41.la libwebpdspdecode_sse41.la
+noinst_LTLIBRARIES += libwebpdsp_neon.la libwebpdspdecode_neon.la
+noinst_LTLIBRARIES += libwebpdspdecode_msa.la
 
 if BUILD_LIBWEBPDECODER
   noinst_LTLIBRARIES += libwebpdspdecode.la
@@ -12,28 +14,24 @@ commondir = $(includedir)/webp
 COMMON_SOURCES =
 COMMON_SOURCES += alpha_processing.c
 COMMON_SOURCES += alpha_processing_mips_dsp_r2.c
+COMMON_SOURCES += common_sse2.h
 COMMON_SOURCES += cpu.c
 COMMON_SOURCES += dec.c
 COMMON_SOURCES += dec_clip_tables.c
 COMMON_SOURCES += dec_mips32.c
 COMMON_SOURCES += dec_mips_dsp_r2.c
-COMMON_SOURCES += dec_neon.c
 COMMON_SOURCES += dsp.h
 COMMON_SOURCES += filters.c
 COMMON_SOURCES += filters_mips_dsp_r2.c
 COMMON_SOURCES += lossless.c
 COMMON_SOURCES += lossless.h
 COMMON_SOURCES += lossless_mips_dsp_r2.c
-COMMON_SOURCES += lossless_neon.c
 COMMON_SOURCES += mips_macro.h
-COMMON_SOURCES += neon.h
 COMMON_SOURCES += rescaler.c
 COMMON_SOURCES += rescaler_mips32.c
 COMMON_SOURCES += rescaler_mips_dsp_r2.c
-COMMON_SOURCES += rescaler_neon.c
 COMMON_SOURCES += upsampling.c
 COMMON_SOURCES += upsampling_mips_dsp_r2.c
-COMMON_SOURCES += upsampling_neon.c
 COMMON_SOURCES += yuv.c
 COMMON_SOURCES += yuv.h
 COMMON_SOURCES += yuv_mips32.c
@@ -48,11 +46,9 @@ ENC_SOURCES += cost_mips_dsp_r2.c
 ENC_SOURCES += enc.c
 ENC_SOURCES += enc_mips32.c
 ENC_SOURCES += enc_mips_dsp_r2.c
-ENC_SOURCES += enc_neon.c
 ENC_SOURCES += lossless_enc.c
 ENC_SOURCES += lossless_enc_mips32.c
 ENC_SOURCES += lossless_enc_mips_dsp_r2.c
-ENC_SOURCES += lossless_enc_neon.c
 
 libwebpdsp_avx2_la_SOURCES =
 libwebpdsp_avx2_la_SOURCES += enc_avx2.c
@@ -76,6 +72,21 @@ libwebpdspdecode_sse2_la_SOURCES += yuv_sse2.c
 libwebpdspdecode_sse2_la_CPPFLAGS = $(libwebpdsp_sse2_la_CPPFLAGS)
 libwebpdspdecode_sse2_la_CFLAGS = $(libwebpdsp_sse2_la_CFLAGS)
 
+libwebpdspdecode_neon_la_SOURCES =
+libwebpdspdecode_neon_la_SOURCES += dec_neon.c
+libwebpdspdecode_neon_la_SOURCES += lossless_neon.c
+libwebpdspdecode_neon_la_SOURCES += neon.h
+libwebpdspdecode_neon_la_SOURCES += rescaler_neon.c
+libwebpdspdecode_neon_la_SOURCES += upsampling_neon.c
+libwebpdspdecode_neon_la_CPPFLAGS = $(libwebpdsp_neon_la_CPPFLAGS)
+libwebpdspdecode_neon_la_CFLAGS = $(libwebpdsp_neon_la_CFLAGS)
+
+libwebpdspdecode_msa_la_SOURCES =
+libwebpdspdecode_msa_la_SOURCES += dec_msa.c
+libwebpdspdecode_msa_la_SOURCES += msa_macro.h
+libwebpdspdecode_msa_la_CPPFLAGS = $(libwebpdsp_la_CPPFLAGS)
+libwebpdspdecode_msa_la_CFLAGS = $(AM_CFLAGS)
+
 libwebpdsp_sse2_la_SOURCES =
 libwebpdsp_sse2_la_SOURCES += argb_sse2.c
 libwebpdsp_sse2_la_SOURCES += cost_sse2.c
@@ -92,6 +103,13 @@ libwebpdsp_sse41_la_CPPFLAGS = $(libwebpdsp_la_CPPFLAGS)
 libwebpdsp_sse41_la_CFLAGS = $(AM_CFLAGS) $(SSE41_FLAGS)
 libwebpdsp_sse41_la_LIBADD = libwebpdspdecode_sse41.la
 
+libwebpdsp_neon_la_SOURCES =
+libwebpdsp_neon_la_SOURCES += enc_neon.c
+libwebpdsp_neon_la_SOURCES += lossless_enc_neon.c
+libwebpdsp_neon_la_CPPFLAGS = $(libwebpdsp_la_CPPFLAGS)
+libwebpdsp_neon_la_CFLAGS = $(AM_CFLAGS) $(NEON_FLAGS)
+libwebpdsp_neon_la_LIBADD = libwebpdspdecode_neon.la
+
 libwebpdsp_la_SOURCES = $(COMMON_SOURCES) $(ENC_SOURCES)
 
 noinst_HEADERS =
@@ -105,6 +123,8 @@ libwebpdsp_la_LDFLAGS = -lm
 libwebpdsp_la_LIBADD =
 libwebpdsp_la_LIBADD += libwebpdsp_avx2.la libwebpdsp_sse2.la
 libwebpdsp_la_LIBADD += libwebpdsp_sse41.la
+libwebpdsp_la_LIBADD += libwebpdsp_neon.la
+libwebpdsp_la_LIBADD += libwebpdspdecode_msa.la
 
 if BUILD_LIBWEBPDECODER
   libwebpdspdecode_la_SOURCES = $(COMMON_SOURCES)
@@ -114,4 +134,6 @@ if BUILD_LIBWEBPDECODER
   libwebpdspdecode_la_LIBADD =
   libwebpdspdecode_la_LIBADD += libwebpdspdecode_sse2.la
   libwebpdspdecode_la_LIBADD += libwebpdspdecode_sse41.la
+  libwebpdspdecode_la_LIBADD += libwebpdspdecode_neon.la
+  libwebpdspdecode_la_LIBADD += libwebpdspdecode_msa.la
 endif

src/dsp/common_sse2.h

@@ -0,0 +1,109 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+// SSE2 code common to several files.
+//
+// Author: Vincent Rabaud (vrabaud@google.com)
+
+#ifndef WEBP_DSP_COMMON_SSE2_H_
+#define WEBP_DSP_COMMON_SSE2_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(WEBP_USE_SSE2)
+
+#include <emmintrin.h>
+
+//------------------------------------------------------------------------------
+// Quite useful macro for debugging. Left here for convenience.
+
+#if 0
+#include <stdio.h>
+static WEBP_INLINE void PrintReg(const __m128i r, const char* const name,
+                                 int size) {
+  int n;
+  union {
+    __m128i r;
+    uint8_t i8[16];
+    uint16_t i16[8];
+    uint32_t i32[4];
+    uint64_t i64[2];
+  } tmp;
+  tmp.r = r;
+  fprintf(stderr, "%s\t: ", name);
+  if (size == 8) {
+    for (n = 0; n < 16; ++n) fprintf(stderr, "%.2x ", tmp.i8[n]);
+  } else if (size == 16) {
+    for (n = 0; n < 8; ++n) fprintf(stderr, "%.4x ", tmp.i16[n]);
+  } else if (size == 32) {
+    for (n = 0; n < 4; ++n) fprintf(stderr, "%.8x ", tmp.i32[n]);
+  } else {
+    for (n = 0; n < 2; ++n) fprintf(stderr, "%.16lx ", tmp.i64[n]);
+  }
+  fprintf(stderr, "\n");
+}
+#endif
+
+//------------------------------------------------------------------------------
+// Math functions.
+
+// Return the sum of all the 8b in the register.
+static WEBP_INLINE int VP8HorizontalAdd8b(const __m128i* const a) {
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i sad8x2 = _mm_sad_epu8(*a, zero);
+  // sum the two sads: sad8x2[0:1] + sad8x2[8:9]
+  const __m128i sum = _mm_add_epi32(sad8x2, _mm_shuffle_epi32(sad8x2, 2));
+  return _mm_cvtsi128_si32(sum);
+}
+
+// Transpose two 4x4 16b matrices horizontally stored in registers.
+static WEBP_INLINE void VP8Transpose_2_4x4_16b(
+    const __m128i* const in0, const __m128i* const in1,
+    const __m128i* const in2, const __m128i* const in3, __m128i* const out0,
+    __m128i* const out1, __m128i* const out2, __m128i* const out3) {
+  // Transpose the two 4x4.
+  // a00 a01 a02 a03   b00 b01 b02 b03
+  // a10 a11 a12 a13   b10 b11 b12 b13
+  // a20 a21 a22 a23   b20 b21 b22 b23
+  // a30 a31 a32 a33   b30 b31 b32 b33
+  const __m128i transpose0_0 = _mm_unpacklo_epi16(*in0, *in1);
+  const __m128i transpose0_1 = _mm_unpacklo_epi16(*in2, *in3);
+  const __m128i transpose0_2 = _mm_unpackhi_epi16(*in0, *in1);
+  const __m128i transpose0_3 = _mm_unpackhi_epi16(*in2, *in3);
+  // a00 a10 a01 a11   a02 a12 a03 a13
+  // a20 a30 a21 a31   a22 a32 a23 a33
+  // b00 b10 b01 b11   b02 b12 b03 b13
+  // b20 b30 b21 b31   b22 b32 b23 b33
+  const __m128i transpose1_0 = _mm_unpacklo_epi32(transpose0_0, transpose0_1);
+  const __m128i transpose1_1 = _mm_unpacklo_epi32(transpose0_2, transpose0_3);
+  const __m128i transpose1_2 = _mm_unpackhi_epi32(transpose0_0, transpose0_1);
+  const __m128i transpose1_3 = _mm_unpackhi_epi32(transpose0_2, transpose0_3);
+  // a00 a10 a20 a30 a01 a11 a21 a31
+  // b00 b10 b20 b30 b01 b11 b21 b31
+  // a02 a12 a22 a32 a03 a13 a23 a33
+  // b02 b12 a22 b32 b03 b13 b23 b33
+  *out0 = _mm_unpacklo_epi64(transpose1_0, transpose1_1);
+  *out1 = _mm_unpackhi_epi64(transpose1_0, transpose1_1);
+  *out2 = _mm_unpacklo_epi64(transpose1_2, transpose1_3);
+  *out3 = _mm_unpackhi_epi64(transpose1_2, transpose1_3);
+  // a00 a10 a20 a30   b00 b10 b20 b30
+  // a01 a11 a21 a31   b01 b11 b21 b31
+  // a02 a12 a22 a32   b02 b12 b22 b32
+  // a03 a13 a23 a33   b03 b13 b23 b33
+}
+
+#endif  // WEBP_USE_SSE2
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // WEBP_DSP_COMMON_SSE2_H_

src/dsp/cpu.c

@@ -13,6 +13,11 @@
 
 #include "./dsp.h"
 
+#if defined(WEBP_HAVE_NEON_RTCD)
+#include <stdio.h>
+#include <string.h>
+#endif
+
 #if defined(WEBP_ANDROID_NEON)
 #include <cpu-features.h>
 #endif
@@ -142,13 +147,33 @@ VP8CPUInfo VP8GetCPUInfo = AndroidCPUInfo;
 // define a dummy function to enable turning off NEON at runtime by setting
 // VP8DecGetCPUInfo = NULL
 static int armCPUInfo(CPUFeature feature) {
-  (void)feature;
+  if (feature != kNEON) return 0;
+#if defined(__linux__) && defined(WEBP_HAVE_NEON_RTCD)
+  {
+    int has_neon = 0;
+    char line[200];
+    FILE* const cpuinfo = fopen("/proc/cpuinfo", "r");
+    if (cpuinfo == NULL) return 0;
+    while (fgets(line, sizeof(line), cpuinfo)) {
+      if (!strncmp(line, "Features", 8)) {
+        if (strstr(line, " neon ") != NULL) {
+          has_neon = 1;
+          break;
+        }
+      }
+    }
+    fclose(cpuinfo);
+    return has_neon;
+  }
+#else
   return 1;
+#endif
 }
 VP8CPUInfo VP8GetCPUInfo = armCPUInfo;
-#elif defined(WEBP_USE_MIPS32) || defined(WEBP_USE_MIPS_DSP_R2)
+#elif defined(WEBP_USE_MIPS32) || defined(WEBP_USE_MIPS_DSP_R2) || \
+      defined(WEBP_USE_MSA)
 static int mipsCPUInfo(CPUFeature feature) {
-  if ((feature == kMIPS32) || (feature == kMIPSdspR2)) {
+  if ((feature == kMIPS32) || (feature == kMIPSdspR2) || (feature == kMSA)) {
     return 1;
   } else {
     return 0;

src/dsp/dec.c

@@ -13,6 +13,7 @@
 
 #include "./dsp.h"
 #include "../dec/vp8i.h"
+#include "../utils/utils.h"
 
 //------------------------------------------------------------------------------
 
@@ -238,7 +239,7 @@ VP8PredFunc VP8PredLuma16[NUM_B_DC_MODES];
 //------------------------------------------------------------------------------
 // 4x4
 
-#define AVG3(a, b, c) (((a) + 2 * (b) + (c) + 2) >> 2)
+#define AVG3(a, b, c) ((uint8_t)(((a) + 2 * (b) + (c) + 2) >> 2))
 #define AVG2(a, b) (((a) + (b) + 1) >> 1)
 
 static void VE4(uint8_t* dst) {    // vertical
@@ -654,6 +655,23 @@ static void HFilter8i(uint8_t* u, uint8_t* v, int stride,
 
 //------------------------------------------------------------------------------
 
+static void DitherCombine8x8(const uint8_t* dither, uint8_t* dst,
+                             int dst_stride) {
+  int i, j;
+  for (j = 0; j < 8; ++j) {
+    for (i = 0; i < 8; ++i) {
+      const int delta0 = dither[i] - VP8_DITHER_AMP_CENTER;
+      const int delta1 =
+          (delta0 + VP8_DITHER_DESCALE_ROUNDER) >> VP8_DITHER_DESCALE;
+      dst[i] = clip_8b((int)dst[i] + delta1);
+    }
+    dst += dst_stride;
+    dither += 8;
+  }
+}
+
+//------------------------------------------------------------------------------
+
 VP8DecIdct2 VP8Transform;
 VP8DecIdct VP8TransformAC3;
 VP8DecIdct VP8TransformUV;
@@ -673,11 +691,15 @@ VP8SimpleFilterFunc VP8SimpleHFilter16;
 VP8SimpleFilterFunc VP8SimpleVFilter16i;
 VP8SimpleFilterFunc VP8SimpleHFilter16i;
 
+void (*VP8DitherCombine8x8)(const uint8_t* dither, uint8_t* dst,
+                            int dst_stride);
+
 extern void VP8DspInitSSE2(void);
 extern void VP8DspInitSSE41(void);
 extern void VP8DspInitNEON(void);
 extern void VP8DspInitMIPS32(void);
 extern void VP8DspInitMIPSdspR2(void);
+extern void VP8DspInitMSA(void);
 
 static volatile VP8CPUInfo dec_last_cpuinfo_used =
     (VP8CPUInfo)&dec_last_cpuinfo_used;
@@ -734,6 +756,8 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8DspInit(void) {
   VP8PredChroma8[5] = DC8uvNoLeft;
   VP8PredChroma8[6] = DC8uvNoTopLeft;
 
+  VP8DitherCombine8x8 = DitherCombine8x8;
+
   // If defined, use CPUInfo() to overwrite some pointers with faster versions.
   if (VP8GetCPUInfo != NULL) {
 #if defined(WEBP_USE_SSE2)
@@ -760,6 +784,11 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8DspInit(void) {
     if (VP8GetCPUInfo(kMIPSdspR2)) {
       VP8DspInitMIPSdspR2();
     }
+#endif
+#if defined(WEBP_USE_MSA)
+    if (VP8GetCPUInfo(kMSA)) {
+      VP8DspInitMSA();
+    }
 #endif
   }
   dec_last_cpuinfo_used = VP8GetCPUInfo;

src/dsp/dec_msa.c

@@ -0,0 +1,172 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+// MSA version of dsp functions
+//
+// Author(s):  Prashant Patil   (prashant.patil@imgtec.com)
+
+
+#include "./dsp.h"
+
+#if defined(WEBP_USE_MSA)
+
+#include "./msa_macro.h"
+
+//------------------------------------------------------------------------------
+// Transforms
+
+#define IDCT_1D_W(in0, in1, in2, in3, out0, out1, out2, out3) {  \
+  v4i32 a1_m, b1_m, c1_m, d1_m;                                  \
+  v4i32 c_tmp1_m, c_tmp2_m, d_tmp1_m, d_tmp2_m;                  \
+  const v4i32 cospi8sqrt2minus1 = __msa_fill_w(20091);           \
+  const v4i32 sinpi8sqrt2 = __msa_fill_w(35468);                 \
+                                                                 \
+  a1_m = in0 + in2;                                              \
+  b1_m = in0 - in2;                                              \
+  c_tmp1_m = (in1 * sinpi8sqrt2) >> 16;                          \
+  c_tmp2_m = in3 + ((in3 * cospi8sqrt2minus1) >> 16);            \
+  c1_m = c_tmp1_m - c_tmp2_m;                                    \
+  d_tmp1_m = in1 + ((in1 * cospi8sqrt2minus1) >> 16);            \
+  d_tmp2_m = (in3 * sinpi8sqrt2) >> 16;                          \
+  d1_m = d_tmp1_m + d_tmp2_m;                                    \
+  BUTTERFLY_4(a1_m, b1_m, c1_m, d1_m, out0, out1, out2, out3);   \
+}
+#define MULT1(a) ((((a) * 20091) >> 16) + (a))
+#define MULT2(a) (((a) * 35468) >> 16)
+
+static void TransformOne(const int16_t* in, uint8_t* dst) {
+  v8i16 input0, input1;
+  v4i32 in0, in1, in2, in3, hz0, hz1, hz2, hz3, vt0, vt1, vt2, vt3;
+  v4i32 res0, res1, res2, res3;
+  const v16i8 zero = { 0 };
+  v16i8 dest0, dest1, dest2, dest3;
+
+  LD_SH2(in, 8, input0, input1);
+  UNPCK_SH_SW(input0, in0, in1);
+  UNPCK_SH_SW(input1, in2, in3);
+  IDCT_1D_W(in0, in1, in2, in3, hz0, hz1, hz2, hz3);
+  TRANSPOSE4x4_SW_SW(hz0, hz1, hz2, hz3, hz0, hz1, hz2, hz3);
+  IDCT_1D_W(hz0, hz1, hz2, hz3, vt0, vt1, vt2, vt3);
+  SRARI_W4_SW(vt0, vt1, vt2, vt3, 3);
+  TRANSPOSE4x4_SW_SW(vt0, vt1, vt2, vt3, vt0, vt1, vt2, vt3);
+  LD_SB4(dst, BPS, dest0, dest1, dest2, dest3);
+  ILVR_B4_SW(zero, dest0, zero, dest1, zero, dest2, zero, dest3,
+             res0, res1, res2, res3);
+  ILVR_H4_SW(zero, res0, zero, res1, zero, res2, zero, res3,
+             res0, res1, res2, res3);
+  ADD4(res0, vt0, res1, vt1, res2, vt2, res3, vt3, res0, res1, res2, res3);
+  CLIP_SW4_0_255(res0, res1, res2, res3);
+  PCKEV_B2_SW(res0, res1, res2, res3, vt0, vt1);
+  res0 = (v4i32)__msa_pckev_b((v16i8)vt0, (v16i8)vt1);
+  ST4x4_UB(res0, res0, 3, 2, 1, 0, dst, BPS);
+}
+
+static void TransformTwo(const int16_t* in, uint8_t* dst, int do_two) {
+  TransformOne(in, dst);
+  if (do_two) {
+    TransformOne(in + 16, dst + 4);
+  }
+}
+
+static void TransformWHT(const int16_t* in, int16_t* out) {
+  v8i16 input0, input1;
+  const v8i16 mask0 = { 0, 1, 2, 3, 8, 9, 10, 11 };
+  const v8i16 mask1 = { 4, 5, 6, 7, 12, 13, 14, 15 };
+  const v8i16 mask2 = { 0, 4, 8, 12, 1, 5, 9, 13 };
+  const v8i16 mask3 = { 3, 7, 11, 15, 2, 6, 10, 14 };
+  v8i16 tmp0, tmp1, tmp2, tmp3;
+  v8i16 out0, out1;
+
+  LD_SH2(in, 8, input0, input1);
+  input1 = SLDI_SH(input1, input1, 8);
+  tmp0 = input0 + input1;
+  tmp1 = input0 - input1;
+  VSHF_H2_SH(tmp0, tmp1, tmp0, tmp1, mask0, mask1, tmp2, tmp3);
+  out0 = tmp2 + tmp3;
+  out1 = tmp2 - tmp3;
+  VSHF_H2_SH(out0, out1, out0, out1, mask2, mask3, input0, input1);
+  tmp0 = input0 + input1;
+  tmp1 = input0 - input1;
+  VSHF_H2_SH(tmp0, tmp1, tmp0, tmp1, mask0, mask1, tmp2, tmp3);
+  tmp0 = tmp2 + tmp3;
+  tmp1 = tmp2 - tmp3;
+  ADDVI_H2_SH(tmp0, 3, tmp1, 3, out0, out1);
+  SRAI_H2_SH(out0, out1, 3);
+  out[0] = __msa_copy_s_h(out0, 0);
+  out[16] = __msa_copy_s_h(out0, 4);
+  out[32] = __msa_copy_s_h(out1, 0);
+  out[48] = __msa_copy_s_h(out1, 4);
+  out[64] = __msa_copy_s_h(out0, 1);
+  out[80] = __msa_copy_s_h(out0, 5);
+  out[96] = __msa_copy_s_h(out1, 1);
+  out[112] = __msa_copy_s_h(out1, 5);
+  out[128] = __msa_copy_s_h(out0, 2);
+  out[144] = __msa_copy_s_h(out0, 6);
+  out[160] = __msa_copy_s_h(out1, 2);
+  out[176] = __msa_copy_s_h(out1, 6);
+  out[192] = __msa_copy_s_h(out0, 3);
+  out[208] = __msa_copy_s_h(out0, 7);
+  out[224] = __msa_copy_s_h(out1, 3);
+  out[240] = __msa_copy_s_h(out1, 7);
+}
+
+static void TransformDC(const int16_t* in, uint8_t* dst) {
+  const int DC = (in[0] + 4) >> 3;
+  const v8i16 tmp0 = __msa_fill_h(DC);
+  ADDBLK_ST4x4_UB(tmp0, tmp0, tmp0, tmp0, dst, BPS);
+}
+
+static void TransformAC3(const int16_t* in, uint8_t* dst) {
+  const int a = in[0] + 4;
+  const int c4 = MULT2(in[4]);
+  const int d4 = MULT1(in[4]);
+  const int in2 = MULT2(in[1]);
+  const int in3 = MULT1(in[1]);
+  v4i32 tmp0 = { 0 };
+  v4i32 out0 = __msa_fill_w(a + d4);
+  v4i32 out1 = __msa_fill_w(a + c4);
+  v4i32 out2 = __msa_fill_w(a - c4);
+  v4i32 out3 = __msa_fill_w(a - d4);
+  v4i32 res0, res1, res2, res3;
+  const v4i32 zero = { 0 };
+  v16u8 dest0, dest1, dest2, dest3;
+
+  INSERT_W4_SW(in3, in2, -in2, -in3, tmp0);
+  ADD4(out0, tmp0, out1, tmp0, out2, tmp0, out3, tmp0,
+       out0, out1, out2, out3);
+  SRAI_W4_SW(out0, out1, out2, out3, 3);
+  LD_UB4(dst, BPS, dest0, dest1, dest2, dest3);
+  ILVR_B4_SW(zero, dest0, zero, dest1, zero, dest2, zero, dest3,
+             res0, res1, res2, res3);
+  ILVR_H4_SW(zero, res0, zero, res1, zero, res2, zero, res3,
+             res0, res1, res2, res3);
+  ADD4(res0, out0, res1, out1, res2, out2, res3, out3, res0, res1, res2, res3);
+  CLIP_SW4_0_255(res0, res1, res2, res3);
+  PCKEV_B2_SW(res0, res1, res2, res3, out0, out1);
+  res0 = (v4i32)__msa_pckev_b((v16i8)out0, (v16i8)out1);
+  ST4x4_UB(res0, res0, 3, 2, 1, 0, dst, BPS);
+}
+
+//------------------------------------------------------------------------------
+// Entry point
+
+extern void VP8DspInitMSA(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void VP8DspInitMSA(void) {
+  VP8TransformWHT = TransformWHT;
+  VP8Transform = TransformTwo;
+  VP8TransformDC = TransformDC;
+  VP8TransformAC3 = TransformAC3;
+}
+
+#else  // !WEBP_USE_MSA
+
+WEBP_DSP_INIT_STUB(VP8DspInitMSA)
+
+#endif  // WEBP_USE_MSA

src/dsp/dec_sse2.c

@@ -21,7 +21,9 @@
 // #define USE_TRANSFORM_AC3
 
 #include <emmintrin.h>
+#include "./common_sse2.h"
 #include "../dec/vp8i.h"
+#include "../utils/utils.h"
 
 //------------------------------------------------------------------------------
 // Transforms (Paragraph 14.4)
@@ -102,34 +104,7 @@ static void Transform(const int16_t* in, uint8_t* dst, int do_two) {
     const __m128i tmp3 = _mm_sub_epi16(a, d);
 
     // Transpose the two 4x4.
-    // a00 a01 a02 a03   b00 b01 b02 b03
-    // a10 a11 a12 a13   b10 b11 b12 b13
-    // a20 a21 a22 a23   b20 b21 b22 b23
-    // a30 a31 a32 a33   b30 b31 b32 b33
-    const __m128i transpose0_0 = _mm_unpacklo_epi16(tmp0, tmp1);
-    const __m128i transpose0_1 = _mm_unpacklo_epi16(tmp2, tmp3);
-    const __m128i transpose0_2 = _mm_unpackhi_epi16(tmp0, tmp1);
-    const __m128i transpose0_3 = _mm_unpackhi_epi16(tmp2, tmp3);
-    // a00 a10 a01 a11   a02 a12 a03 a13
-    // a20 a30 a21 a31   a22 a32 a23 a33
-    // b00 b10 b01 b11   b02 b12 b03 b13
-    // b20 b30 b21 b31   b22 b32 b23 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpacklo_epi32(transpose0_2, transpose0_3);
-    const __m128i transpose1_2 = _mm_unpackhi_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_3 = _mm_unpackhi_epi32(transpose0_2, transpose0_3);
-    // a00 a10 a20 a30 a01 a11 a21 a31
-    // b00 b10 b20 b30 b01 b11 b21 b31
-    // a02 a12 a22 a32 a03 a13 a23 a33
-    // b02 b12 a22 b32 b03 b13 b23 b33
-    T0 = _mm_unpacklo_epi64(transpose1_0, transpose1_1);
-    T1 = _mm_unpackhi_epi64(transpose1_0, transpose1_1);
-    T2 = _mm_unpacklo_epi64(transpose1_2, transpose1_3);
-    T3 = _mm_unpackhi_epi64(transpose1_2, transpose1_3);
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    VP8Transpose_2_4x4_16b(&tmp0, &tmp1, &tmp2, &tmp3, &T0, &T1, &T2, &T3);
   }
 
   // Horizontal pass and subsequent transpose.
@@ -164,34 +139,8 @@ static void Transform(const int16_t* in, uint8_t* dst, int do_two) {
     const __m128i shifted3 = _mm_srai_epi16(tmp3, 3);
 
     // Transpose the two 4x4.
-    // a00 a01 a02 a03   b00 b01 b02 b03
-    // a10 a11 a12 a13   b10 b11 b12 b13
-    // a20 a21 a22 a23   b20 b21 b22 b23
-    // a30 a31 a32 a33   b30 b31 b32 b33
-    const __m128i transpose0_0 = _mm_unpacklo_epi16(shifted0, shifted1);
-    const __m128i transpose0_1 = _mm_unpacklo_epi16(shifted2, shifted3);
-    const __m128i transpose0_2 = _mm_unpackhi_epi16(shifted0, shifted1);
-    const __m128i transpose0_3 = _mm_unpackhi_epi16(shifted2, shifted3);
-    // a00 a10 a01 a11   a02 a12 a03 a13
-    // a20 a30 a21 a31   a22 a32 a23 a33
-    // b00 b10 b01 b11   b02 b12 b03 b13
-    // b20 b30 b21 b31   b22 b32 b23 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpacklo_epi32(transpose0_2, transpose0_3);
-    const __m128i transpose1_2 = _mm_unpackhi_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_3 = _mm_unpackhi_epi32(transpose0_2, transpose0_3);
-    // a00 a10 a20 a30 a01 a11 a21 a31
-    // b00 b10 b20 b30 b01 b11 b21 b31
-    // a02 a12 a22 a32 a03 a13 a23 a33
-    // b02 b12 a22 b32 b03 b13 b23 b33
-    T0 = _mm_unpacklo_epi64(transpose1_0, transpose1_1);
-    T1 = _mm_unpackhi_epi64(transpose1_0, transpose1_1);
-    T2 = _mm_unpacklo_epi64(transpose1_2, transpose1_3);
-    T3 = _mm_unpackhi_epi64(transpose1_2, transpose1_3);
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    VP8Transpose_2_4x4_16b(&shifted0, &shifted1, &shifted2, &shifted3, &T0, &T1,
+                        &T2, &T3);
   }
 
   // Add inverse transform to 'dst' and store.

src/dsp/dec_sse41.c

@@ -17,6 +17,7 @@
 
 #include <smmintrin.h>
 #include "../dec/vp8i.h"
+#include "../utils/utils.h"
 
 static void HE16(uint8_t* dst) {     // horizontal
   int j;

src/dsp/dsp.h

@@ -14,8 +14,11 @@
 #ifndef WEBP_DSP_DSP_H_
 #define WEBP_DSP_DSP_H_
 
+#ifdef HAVE_CONFIG_H
+#include "../webp/config.h"
+#endif
+
 #include "../webp/types.h"
-#include "../utils/utils.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -72,7 +75,8 @@ extern "C" {
 // The intrinsics currently cause compiler errors with arm-nacl-gcc and the
 // inline assembly would need to be modified for use with Native Client.
 #if (defined(__ARM_NEON__) || defined(WEBP_ANDROID_NEON) || \
-     defined(__aarch64__)) && !defined(__native_client__)
+     defined(__aarch64__) || defined(WEBP_HAVE_NEON)) && \
+    !defined(__native_client__)
 #define WEBP_USE_NEON
 #endif
 
@@ -92,6 +96,10 @@ extern "C" {
 #endif
 #endif
 
+#if defined(__mips_msa) && defined(__mips_isa_rev) && (__mips_isa_rev >= 5)
+#define WEBP_USE_MSA
+#endif
+
 // This macro prevents thread_sanitizer from reporting known concurrent writes.
 #define WEBP_TSAN_IGNORE_FUNCTION
 #if defined(__has_feature)
@@ -101,6 +109,27 @@ extern "C" {
 #endif
 #endif
 
+#define WEBP_UBSAN_IGNORE_UNDEF
+#define WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW
+#if !defined(WEBP_FORCE_ALIGNED) && defined(__clang__) && \
+    defined(__has_attribute)
+#if __has_attribute(no_sanitize)
+// This macro prevents the undefined behavior sanitizer from reporting
+// failures. This is only meant to silence unaligned loads on platforms that
+// are known to support them.
+#undef WEBP_UBSAN_IGNORE_UNDEF
+#define WEBP_UBSAN_IGNORE_UNDEF \
+  __attribute__((no_sanitize("undefined")))
+
+// This macro prevents the undefined behavior sanitizer from reporting
+// failures related to unsigned integer overflows. This is only meant to
+// silence cases where this well defined behavior is expected.
+#undef WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW
+#define WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW \
+  __attribute__((no_sanitize("unsigned-integer-overflow")))
+#endif
+#endif
+
 typedef enum {
   kSSE2,
   kSSE3,
@@ -109,7 +138,8 @@ typedef enum {
   kAVX2,
   kNEON,
   kMIPS32,
-  kMIPSdspR2
+  kMIPSdspR2,
+  kMSA
 } CPUFeature;
 // returns true if the CPU supports the feature.
 typedef int (*VP8CPUInfo)(CPUFeature feature);
@@ -151,6 +181,8 @@ typedef int (*VP8Metric)(const uint8_t* pix, const uint8_t* ref);
 extern VP8Metric VP8SSE16x16, VP8SSE16x8, VP8SSE8x8, VP8SSE4x4;
 typedef int (*VP8WMetric)(const uint8_t* pix, const uint8_t* ref,
                           const uint16_t* const weights);
+// The weights for VP8TDisto4x4 and VP8TDisto16x16 contain a row-major
+// 4 by 4 symmetric matrix.
 extern VP8WMetric VP8TDisto4x4, VP8TDisto16x16;
 
 typedef void (*VP8BlockCopy)(const uint8_t* src, uint8_t* dst);
@@ -213,6 +245,35 @@ extern VP8GetResidualCostFunc VP8GetResidualCost;
 // must be called before anything using the above
 void VP8EncDspCostInit(void);
 
+//------------------------------------------------------------------------------
+// SSIM utils
+
+// struct for accumulating statistical moments
+typedef struct {
+  double w;              // sum(w_i) : sum of weights
+  double xm, ym;         // sum(w_i * x_i), sum(w_i * y_i)
+  double xxm, xym, yym;  // sum(w_i * x_i * x_i), etc.
+} VP8DistoStats;
+
+#define VP8_SSIM_KERNEL 3   // total size of the kernel: 2 * VP8_SSIM_KERNEL + 1
+typedef void (*VP8SSIMAccumulateClippedFunc)(const uint8_t* src1, int stride1,
+                                             const uint8_t* src2, int stride2,
+                                             int xo, int yo,  // center position
+                                             int W, int H,    // plane dimension
+                                             VP8DistoStats* const stats);
+
+// This version is called with the guarantee that you can load 8 bytes and
+// 8 rows at offset src1 and src2
+typedef void (*VP8SSIMAccumulateFunc)(const uint8_t* src1, int stride1,
+                                      const uint8_t* src2, int stride2,
+                                      VP8DistoStats* const stats);
+
+extern VP8SSIMAccumulateFunc VP8SSIMAccumulate;         // unclipped / unchecked
+extern VP8SSIMAccumulateClippedFunc VP8SSIMAccumulateClipped;   // with clipping
+
+// must be called before using any of the above directly
+void VP8SSIMDspInit(void);
+
 //------------------------------------------------------------------------------
 // Decoding
 
@@ -265,6 +326,15 @@ extern VP8LumaFilterFunc VP8HFilter16i;
 extern VP8ChromaFilterFunc VP8VFilter8i;  // filtering u and v altogether
 extern VP8ChromaFilterFunc VP8HFilter8i;
 
+// Dithering. Combines dithering values (centered around 128) with dst[],
+// according to: dst[] = clip(dst[] + (((dither[]-128) + 8) >> 4)
+#define VP8_DITHER_DESCALE 4
+#define VP8_DITHER_DESCALE_ROUNDER (1 << (VP8_DITHER_DESCALE - 1))
+#define VP8_DITHER_AMP_BITS 7
+#define VP8_DITHER_AMP_CENTER (1 << VP8_DITHER_AMP_BITS)
+extern void (*VP8DitherCombine8x8)(const uint8_t* dither, uint8_t* dst,
+                                   int dst_stride);
+
 // must be called before anything using the above
 void VP8DspInit(void);
 
@@ -472,8 +542,10 @@ typedef enum {     // Filter types.
 
 typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height,
                                int stride, uint8_t* out);
-typedef void (*WebPUnfilterFunc)(int width, int height, int stride,
-                                 int row, int num_rows, uint8_t* data);
+// In-place un-filtering.
+// Warning! 'prev_line' pointer can be equal to 'cur_line' or 'preds'.
+typedef void (*WebPUnfilterFunc)(const uint8_t* prev_line, const uint8_t* preds,
+                                 uint8_t* cur_line, int width);
 
 // Filter the given data using the given predictor.
 // 'in' corresponds to a 2-dimensional pixel array of size (stride * height)

src/dsp/enc.c

@@ -69,7 +69,7 @@ static void CollectHistogram(const uint8_t* ref, const uint8_t* pred,
 
     // Convert coefficients to bin.
     for (k = 0; k < 16; ++k) {
-      const int v = abs(out[k]) >> 3;  // TODO(skal): add rounding?
+      const int v = abs(out[k]) >> 3;
       const int clipped_value = clip_max(v, MAX_COEFF_THRESH);
       ++distribution[clipped_value];
     }
@@ -335,7 +335,7 @@ static void Intra16Preds(uint8_t* dst,
 // luma 4x4 prediction
 
 #define DST(x, y) dst[(x) + (y) * BPS]
-#define AVG3(a, b, c) (((a) + 2 * (b) + (c) + 2) >> 2)
+#define AVG3(a, b, c) ((uint8_t)(((a) + 2 * (b) + (c) + 2) >> 2))
 #define AVG2(a, b) (((a) + (b) + 1) >> 1)
 
 static void VE4(uint8_t* dst, const uint8_t* top) {    // vertical
@@ -559,6 +559,7 @@ static int SSE4x4(const uint8_t* a, const uint8_t* b) {
 
 // Hadamard transform
 // Returns the weighted sum of the absolute value of transformed coefficients.
+// w[] contains a row-major 4 by 4 symmetric matrix.
 static int TTransform(const uint8_t* in, const uint16_t* w) {
   int sum = 0;
   int tmp[16];
@@ -636,7 +637,7 @@ static int QuantizeBlock(int16_t in[16], int16_t out[16],
       int level = QUANTDIV(coeff, iQ, B);
       if (level > MAX_LEVEL) level = MAX_LEVEL;
       if (sign) level = -level;
-      in[j] = level * Q;
+      in[j] = level * (int)Q;
       out[n] = level;
       if (level) last = n;
     } else {
@@ -670,7 +671,7 @@ static int QuantizeBlockWHT(int16_t in[16], int16_t out[16],
       int level = QUANTDIV(coeff, iQ, B);
       if (level > MAX_LEVEL) level = MAX_LEVEL;
       if (sign) level = -level;
-      in[j] = level * Q;
+      in[j] = level * (int)Q;
       out[n] = level;
       if (level) last = n;
     } else {
@@ -701,6 +702,68 @@ static void Copy16x8(const uint8_t* src, uint8_t* dst) {
   Copy(src, dst, 16, 8);
 }
 
+//------------------------------------------------------------------------------
+
+static void SSIMAccumulateClipped(const uint8_t* src1, int stride1,
+                                  const uint8_t* src2, int stride2,
+                                  int xo, int yo, int W, int H,
+                                  VP8DistoStats* const stats) {
+  const int ymin = (yo - VP8_SSIM_KERNEL < 0) ? 0 : yo - VP8_SSIM_KERNEL;
+  const int ymax = (yo + VP8_SSIM_KERNEL > H - 1) ? H - 1
+                                                  : yo + VP8_SSIM_KERNEL;
+  const int xmin = (xo - VP8_SSIM_KERNEL < 0) ? 0 : xo - VP8_SSIM_KERNEL;
+  const int xmax = (xo + VP8_SSIM_KERNEL > W - 1) ? W - 1
+                                                  : xo + VP8_SSIM_KERNEL;
+  int x, y;
+  src1 += ymin * stride1;
+  src2 += ymin * stride2;
+  for (y = ymin; y <= ymax; ++y, src1 += stride1, src2 += stride2) {
+    for (x = xmin; x <= xmax; ++x) {
+      const int s1 = src1[x];
+      const int s2 = src2[x];
+      stats->w   += 1;
+      stats->xm  += s1;
+      stats->ym  += s2;
+      stats->xxm += s1 * s1;
+      stats->xym += s1 * s2;
+      stats->yym += s2 * s2;
+    }
+  }
+}
+
+static void SSIMAccumulate(const uint8_t* src1, int stride1,
+                           const uint8_t* src2, int stride2,
+                           VP8DistoStats* const stats) {
+  int x, y;
+  for (y = 0; y <= 2 * VP8_SSIM_KERNEL; ++y, src1 += stride1, src2 += stride2) {
+    for (x = 0; x <= 2 * VP8_SSIM_KERNEL; ++x) {
+      const int s1 = src1[x];
+      const int s2 = src2[x];
+      stats->w   += 1;
+      stats->xm  += s1;
+      stats->ym  += s2;
+      stats->xxm += s1 * s1;
+      stats->xym += s1 * s2;
+      stats->yym += s2 * s2;
+    }
+  }
+}
+
+VP8SSIMAccumulateFunc VP8SSIMAccumulate;
+VP8SSIMAccumulateClippedFunc VP8SSIMAccumulateClipped;
+
+static volatile VP8CPUInfo ssim_last_cpuinfo_used =
+    (VP8CPUInfo)&ssim_last_cpuinfo_used;
+
+WEBP_TSAN_IGNORE_FUNCTION void VP8SSIMDspInit(void) {
+  if (ssim_last_cpuinfo_used == VP8GetCPUInfo) return;
+
+  VP8SSIMAccumulate = SSIMAccumulate;
+  VP8SSIMAccumulateClipped = SSIMAccumulateClipped;
+
+  ssim_last_cpuinfo_used = VP8GetCPUInfo;
+}
+
 //------------------------------------------------------------------------------
 // Initialization
 

src/dsp/enc_mips_dsp_r2.c

@@ -1393,8 +1393,6 @@ static void FTransformWHT(const int16_t* in, int16_t* out) {
   "absq_s.ph  %[temp1],  %[temp1]                      \n\t"                   \
   "absq_s.ph  %[temp2],  %[temp2]                      \n\t"                   \
   "absq_s.ph  %[temp3],  %[temp3]                      \n\t"                   \
-  /* TODO(skal): add rounding ? shra_r.ph : shra.ph */                         \
-  /*             for following 4 instructions       */                         \
   "shra.ph    %[temp0],  %[temp0],    3                \n\t"                   \
   "shra.ph    %[temp1],  %[temp1],    3                \n\t"                   \
   "shra.ph    %[temp2],  %[temp2],    3                \n\t"                   \

src/dsp/enc_neon.c

@@ -560,21 +560,6 @@ static void FTransformWHT(const int16_t* src, int16_t* out) {
 // a 26ae, b 26ae
 // a 37bf, b 37bf
 //
-static WEBP_INLINE uint8x8x4_t DistoTranspose4x4U8(uint8x8x4_t d4_in) {
-  const uint8x8x2_t d2_tmp0 = vtrn_u8(d4_in.val[0], d4_in.val[1]);
-  const uint8x8x2_t d2_tmp1 = vtrn_u8(d4_in.val[2], d4_in.val[3]);
-  const uint16x4x2_t d2_tmp2 = vtrn_u16(vreinterpret_u16_u8(d2_tmp0.val[0]),
-                                        vreinterpret_u16_u8(d2_tmp1.val[0]));
-  const uint16x4x2_t d2_tmp3 = vtrn_u16(vreinterpret_u16_u8(d2_tmp0.val[1]),
-                                        vreinterpret_u16_u8(d2_tmp1.val[1]));
-
-  d4_in.val[0] = vreinterpret_u8_u16(d2_tmp2.val[0]);
-  d4_in.val[2] = vreinterpret_u8_u16(d2_tmp2.val[1]);
-  d4_in.val[1] = vreinterpret_u8_u16(d2_tmp3.val[0]);
-  d4_in.val[3] = vreinterpret_u8_u16(d2_tmp3.val[1]);
-  return d4_in;
-}
-
 static WEBP_INLINE int16x8x4_t DistoTranspose4x4S16(int16x8x4_t q4_in) {
   const int16x8x2_t q2_tmp0 = vtrnq_s16(q4_in.val[0], q4_in.val[1]);
   const int16x8x2_t q2_tmp1 = vtrnq_s16(q4_in.val[2], q4_in.val[3]);
@@ -589,41 +574,40 @@ static WEBP_INLINE int16x8x4_t DistoTranspose4x4S16(int16x8x4_t q4_in) {
   return q4_in;
 }
 
-static WEBP_INLINE int16x8x4_t DistoHorizontalPass(const uint8x8x4_t d4_in) {
+static WEBP_INLINE int16x8x4_t DistoHorizontalPass(const int16x8x4_t q4_in) {
   // {a0, a1} = {in[0] + in[2], in[1] + in[3]}
   // {a3, a2} = {in[0] - in[2], in[1] - in[3]}
-  const int16x8_t q_a0 = vreinterpretq_s16_u16(vaddl_u8(d4_in.val[0],
-                                                        d4_in.val[2]));
-  const int16x8_t q_a1 = vreinterpretq_s16_u16(vaddl_u8(d4_in.val[1],
-                                                        d4_in.val[3]));
-  const int16x8_t q_a3 = vreinterpretq_s16_u16(vsubl_u8(d4_in.val[0],
-                                                        d4_in.val[2]));
-  const int16x8_t q_a2 = vreinterpretq_s16_u16(vsubl_u8(d4_in.val[1],
-                                                        d4_in.val[3]));
+  const int16x8_t q_a0 = vaddq_s16(q4_in.val[0], q4_in.val[2]);
+  const int16x8_t q_a1 = vaddq_s16(q4_in.val[1], q4_in.val[3]);
+  const int16x8_t q_a3 = vsubq_s16(q4_in.val[0], q4_in.val[2]);
+  const int16x8_t q_a2 = vsubq_s16(q4_in.val[1], q4_in.val[3]);
   int16x8x4_t q4_out;
   // tmp[0] = a0 + a1
   // tmp[1] = a3 + a2
   // tmp[2] = a3 - a2
   // tmp[3] = a0 - a1
   INIT_VECTOR4(q4_out,
-               vaddq_s16(q_a0, q_a1), vaddq_s16(q_a3, q_a2),
-               vsubq_s16(q_a3, q_a2), vsubq_s16(q_a0, q_a1));
+               vabsq_s16(vaddq_s16(q_a0, q_a1)),
+               vabsq_s16(vaddq_s16(q_a3, q_a2)),
+               vabdq_s16(q_a3, q_a2), vabdq_s16(q_a0, q_a1));
   return q4_out;
 }
 
-static WEBP_INLINE int16x8x4_t DistoVerticalPass(int16x8x4_t q4_in) {
-  const int16x8_t q_a0 = vaddq_s16(q4_in.val[0], q4_in.val[2]);
-  const int16x8_t q_a1 = vaddq_s16(q4_in.val[1], q4_in.val[3]);
-  const int16x8_t q_a2 = vsubq_s16(q4_in.val[1], q4_in.val[3]);
-  const int16x8_t q_a3 = vsubq_s16(q4_in.val[0], q4_in.val[2]);
+static WEBP_INLINE int16x8x4_t DistoVerticalPass(const uint8x8x4_t q4_in) {
+  const int16x8_t q_a0 = vreinterpretq_s16_u16(vaddl_u8(q4_in.val[0],
+                                                        q4_in.val[2]));
+  const int16x8_t q_a1 = vreinterpretq_s16_u16(vaddl_u8(q4_in.val[1],
+                                                        q4_in.val[3]));
+  const int16x8_t q_a2 = vreinterpretq_s16_u16(vsubl_u8(q4_in.val[1],
+                                                        q4_in.val[3]));
+  const int16x8_t q_a3 = vreinterpretq_s16_u16(vsubl_u8(q4_in.val[0],
+                                                        q4_in.val[2]));
+  int16x8x4_t q4_out;
 
-  q4_in.val[0] = vaddq_s16(q_a0, q_a1);
-  q4_in.val[1] = vaddq_s16(q_a3, q_a2);
-  q4_in.val[2] = vabdq_s16(q_a3, q_a2);
-  q4_in.val[3] = vabdq_s16(q_a0, q_a1);
-  q4_in.val[0] = vabsq_s16(q4_in.val[0]);
-  q4_in.val[1] = vabsq_s16(q4_in.val[1]);
-  return q4_in;
+  INIT_VECTOR4(q4_out,
+               vaddq_s16(q_a0, q_a1), vaddq_s16(q_a3, q_a2),
+               vsubq_s16(q_a3, q_a2), vsubq_s16(q_a0, q_a1));
+  return q4_out;
 }
 
 static WEBP_INLINE int16x4x4_t DistoLoadW(const uint16_t* w) {
@@ -667,6 +651,7 @@ static WEBP_INLINE int32x2_t DistoSum(const int16x8x4_t q4_in,
 
 // Hadamard transform
 // Returns the weighted sum of the absolute value of transformed coefficients.
+// w[] contains a row-major 4 by 4 symmetric matrix.
 static int Disto4x4(const uint8_t* const a, const uint8_t* const b,
                     const uint16_t* const w) {
   uint32x2_t d_in_ab_0123 = vdup_n_u32(0);
@@ -691,18 +676,19 @@ static int Disto4x4(const uint8_t* const a, const uint8_t* const b,
                vreinterpret_u8_u32(d_in_ab_cdef));
 
   {
-    // horizontal pass
-    const uint8x8x4_t d4_t = DistoTranspose4x4U8(d4_in);
-    const int16x8x4_t q4_h = DistoHorizontalPass(d4_t);
+    // Vertical pass first to avoid a transpose (vertical and horizontal passes
+    // are commutative because w/kWeightY is symmetric) and subsequent
+    // transpose.
+    const int16x8x4_t q4_v = DistoVerticalPass(d4_in);
     const int16x4x4_t d4_w = DistoLoadW(w);
-    // vertical pass
-    const int16x8x4_t q4_t = DistoTranspose4x4S16(q4_h);
-    const int16x8x4_t q4_v = DistoVerticalPass(q4_t);
-    int32x2_t d_sum = DistoSum(q4_v, d4_w);
+    // horizontal pass
+    const int16x8x4_t q4_t = DistoTranspose4x4S16(q4_v);
+    const int16x8x4_t q4_h = DistoHorizontalPass(q4_t);
+    int32x2_t d_sum = DistoSum(q4_h, d4_w);
 
     // abs(sum2 - sum1) >> 5
     d_sum = vabs_s32(d_sum);
-    d_sum  = vshr_n_s32(d_sum, 5);
+    d_sum = vshr_n_s32(d_sum, 5);
     return vget_lane_s32(d_sum, 0);
   }
 }

src/dsp/enc_sse2.c

@@ -17,38 +17,10 @@
 #include <stdlib.h>  // for abs()
 #include <emmintrin.h>
 
+#include "./common_sse2.h"
 #include "../enc/cost.h"
 #include "../enc/vp8enci.h"
 
-//------------------------------------------------------------------------------
-// Quite useful macro for debugging. Left here for convenience.
-
-#if 0
-#include <stdio.h>
-static void PrintReg(const __m128i r, const char* const name, int size) {
-  int n;
-  union {
-    __m128i r;
-    uint8_t i8[16];
-    uint16_t i16[8];
-    uint32_t i32[4];
-    uint64_t i64[2];
-  } tmp;
-  tmp.r = r;
-  fprintf(stderr, "%s\t: ", name);
-  if (size == 8) {
-    for (n = 0; n < 16; ++n) fprintf(stderr, "%.2x ", tmp.i8[n]);
-  } else if (size == 16) {
-    for (n = 0; n < 8; ++n) fprintf(stderr, "%.4x ", tmp.i16[n]);
-  } else if (size == 32) {
-    for (n = 0; n < 4; ++n) fprintf(stderr, "%.8x ", tmp.i32[n]);
-  } else {
-    for (n = 0; n < 2; ++n) fprintf(stderr, "%.16lx ", tmp.i64[n]);
-  }
-  fprintf(stderr, "\n");
-}
-#endif
-
 //------------------------------------------------------------------------------
 // Transforms (Paragraph 14.4)
 
@@ -131,34 +103,7 @@ static void ITransform(const uint8_t* ref, const int16_t* in, uint8_t* dst,
     const __m128i tmp3 = _mm_sub_epi16(a, d);
 
     // Transpose the two 4x4.
-    // a00 a01 a02 a03   b00 b01 b02 b03
-    // a10 a11 a12 a13   b10 b11 b12 b13
-    // a20 a21 a22 a23   b20 b21 b22 b23
-    // a30 a31 a32 a33   b30 b31 b32 b33
-    const __m128i transpose0_0 = _mm_unpacklo_epi16(tmp0, tmp1);
-    const __m128i transpose0_1 = _mm_unpacklo_epi16(tmp2, tmp3);
-    const __m128i transpose0_2 = _mm_unpackhi_epi16(tmp0, tmp1);
-    const __m128i transpose0_3 = _mm_unpackhi_epi16(tmp2, tmp3);
-    // a00 a10 a01 a11   a02 a12 a03 a13
-    // a20 a30 a21 a31   a22 a32 a23 a33
-    // b00 b10 b01 b11   b02 b12 b03 b13
-    // b20 b30 b21 b31   b22 b32 b23 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpacklo_epi32(transpose0_2, transpose0_3);
-    const __m128i transpose1_2 = _mm_unpackhi_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_3 = _mm_unpackhi_epi32(transpose0_2, transpose0_3);
-    // a00 a10 a20 a30 a01 a11 a21 a31
-    // b00 b10 b20 b30 b01 b11 b21 b31
-    // a02 a12 a22 a32 a03 a13 a23 a33
-    // b02 b12 a22 b32 b03 b13 b23 b33
-    T0 = _mm_unpacklo_epi64(transpose1_0, transpose1_1);
-    T1 = _mm_unpackhi_epi64(transpose1_0, transpose1_1);
-    T2 = _mm_unpacklo_epi64(transpose1_2, transpose1_3);
-    T3 = _mm_unpackhi_epi64(transpose1_2, transpose1_3);
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    VP8Transpose_2_4x4_16b(&tmp0, &tmp1, &tmp2, &tmp3, &T0, &T1, &T2, &T3);
   }
 
   // Horizontal pass and subsequent transpose.
@@ -193,34 +138,8 @@ static void ITransform(const uint8_t* ref, const int16_t* in, uint8_t* dst,
     const __m128i shifted3 = _mm_srai_epi16(tmp3, 3);
 
     // Transpose the two 4x4.
-    // a00 a01 a02 a03   b00 b01 b02 b03
-    // a10 a11 a12 a13   b10 b11 b12 b13
-    // a20 a21 a22 a23   b20 b21 b22 b23
-    // a30 a31 a32 a33   b30 b31 b32 b33
-    const __m128i transpose0_0 = _mm_unpacklo_epi16(shifted0, shifted1);
-    const __m128i transpose0_1 = _mm_unpacklo_epi16(shifted2, shifted3);
-    const __m128i transpose0_2 = _mm_unpackhi_epi16(shifted0, shifted1);
-    const __m128i transpose0_3 = _mm_unpackhi_epi16(shifted2, shifted3);
-    // a00 a10 a01 a11   a02 a12 a03 a13
-    // a20 a30 a21 a31   a22 a32 a23 a33
-    // b00 b10 b01 b11   b02 b12 b03 b13
-    // b20 b30 b21 b31   b22 b32 b23 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpacklo_epi32(transpose0_2, transpose0_3);
-    const __m128i transpose1_2 = _mm_unpackhi_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_3 = _mm_unpackhi_epi32(transpose0_2, transpose0_3);
-    // a00 a10 a20 a30 a01 a11 a21 a31
-    // b00 b10 b20 b30 b01 b11 b21 b31
-    // a02 a12 a22 a32 a03 a13 a23 a33
-    // b02 b12 a22 b32 b03 b13 b23 b33
-    T0 = _mm_unpacklo_epi64(transpose1_0, transpose1_1);
-    T1 = _mm_unpackhi_epi64(transpose1_0, transpose1_1);
-    T2 = _mm_unpacklo_epi64(transpose1_2, transpose1_3);
-    T3 = _mm_unpackhi_epi64(transpose1_2, transpose1_3);
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    VP8Transpose_2_4x4_16b(&shifted0, &shifted1, &shifted2, &shifted3, &T0, &T1,
+                        &T2, &T3);
   }
 
   // Add inverse transform to 'ref' and store.
@@ -373,42 +292,42 @@ static void FTransformPass2(const __m128i* const v01, const __m128i* const v32,
 
 static void FTransform(const uint8_t* src, const uint8_t* ref, int16_t* out) {
   const __m128i zero = _mm_setzero_si128();
-
-  // Load src and convert to 16b.
+  // Load src.
   const __m128i src0 = _mm_loadl_epi64((const __m128i*)&src[0 * BPS]);
   const __m128i src1 = _mm_loadl_epi64((const __m128i*)&src[1 * BPS]);
   const __m128i src2 = _mm_loadl_epi64((const __m128i*)&src[2 * BPS]);
   const __m128i src3 = _mm_loadl_epi64((const __m128i*)&src[3 * BPS]);
-  const __m128i src_0 = _mm_unpacklo_epi8(src0, zero);
-  const __m128i src_1 = _mm_unpacklo_epi8(src1, zero);
-  const __m128i src_2 = _mm_unpacklo_epi8(src2, zero);
-  const __m128i src_3 = _mm_unpacklo_epi8(src3, zero);
-  // Load ref and convert to 16b.
+  // 00 01 02 03 *
+  // 10 11 12 13 *
+  // 20 21 22 23 *
+  // 30 31 32 33 *
+  // Shuffle.
+  const __m128i src_0 = _mm_unpacklo_epi16(src0, src1);
+  const __m128i src_1 = _mm_unpacklo_epi16(src2, src3);
+  // 00 01 10 11 02 03 12 13 * * ...
+  // 20 21 30 31 22 22 32 33 * * ...
+
+  // Load ref.
   const __m128i ref0 = _mm_loadl_epi64((const __m128i*)&ref[0 * BPS]);
   const __m128i ref1 = _mm_loadl_epi64((const __m128i*)&ref[1 * BPS]);
   const __m128i ref2 = _mm_loadl_epi64((const __m128i*)&ref[2 * BPS]);
   const __m128i ref3 = _mm_loadl_epi64((const __m128i*)&ref[3 * BPS]);
-  const __m128i ref_0 = _mm_unpacklo_epi8(ref0, zero);
-  const __m128i ref_1 = _mm_unpacklo_epi8(ref1, zero);
-  const __m128i ref_2 = _mm_unpacklo_epi8(ref2, zero);
-  const __m128i ref_3 = _mm_unpacklo_epi8(ref3, zero);
-  // Compute difference. -> 00 01 02 03 00 00 00 00
-  const __m128i diff0 = _mm_sub_epi16(src_0, ref_0);
-  const __m128i diff1 = _mm_sub_epi16(src_1, ref_1);
-  const __m128i diff2 = _mm_sub_epi16(src_2, ref_2);
-  const __m128i diff3 = _mm_sub_epi16(src_3, ref_3);
+  const __m128i ref_0 = _mm_unpacklo_epi16(ref0, ref1);
+  const __m128i ref_1 = _mm_unpacklo_epi16(ref2, ref3);
 
-  // Unpack and shuffle
-  // 00 01 02 03   0 0 0 0
-  // 10 11 12 13   0 0 0 0
-  // 20 21 22 23   0 0 0 0
-  // 30 31 32 33   0 0 0 0
-  const __m128i shuf01 = _mm_unpacklo_epi32(diff0, diff1);
-  const __m128i shuf23 = _mm_unpacklo_epi32(diff2, diff3);
+  // Convert both to 16 bit.
+  const __m128i src_0_16b = _mm_unpacklo_epi8(src_0, zero);
+  const __m128i src_1_16b = _mm_unpacklo_epi8(src_1, zero);
+  const __m128i ref_0_16b = _mm_unpacklo_epi8(ref_0, zero);
+  const __m128i ref_1_16b = _mm_unpacklo_epi8(ref_1, zero);
+
+  // Compute the difference.
+  const __m128i row01 = _mm_sub_epi16(src_0_16b, ref_0_16b);
+  const __m128i row23 = _mm_sub_epi16(src_1_16b, ref_1_16b);
   __m128i v01, v32;
 
   // First pass
-  FTransformPass1(&shuf01, &shuf23, &v01, &v32);
+  FTransformPass1(&row01, &row23, &v01, &v32);
 
   // Second pass
   FTransformPass2(&v01, &v32, out);
@@ -463,8 +382,7 @@ static void FTransform2(const uint8_t* src, const uint8_t* ref, int16_t* out) {
 }
 
 static void FTransformWHTRow(const int16_t* const in, __m128i* const out) {
-  const __m128i kMult1 = _mm_set_epi16(0, 0, 0, 0, 1, 1, 1, 1);
-  const __m128i kMult2 = _mm_set_epi16(0, 0, 0, 0, -1, 1, -1, 1);
+  const __m128i kMult = _mm_set_epi16(-1, 1, -1, 1, 1, 1, 1, 1);
   const __m128i src0 = _mm_loadl_epi64((__m128i*)&in[0 * 16]);
   const __m128i src1 = _mm_loadl_epi64((__m128i*)&in[1 * 16]);
   const __m128i src2 = _mm_loadl_epi64((__m128i*)&in[2 * 16]);
@@ -473,33 +391,38 @@ static void FTransformWHTRow(const int16_t* const in, __m128i* const out) {
   const __m128i A23 = _mm_unpacklo_epi16(src2, src3);  // A2 A3 | ...
   const __m128i B0 = _mm_adds_epi16(A01, A23);    // a0 | a1 | ...
   const __m128i B1 = _mm_subs_epi16(A01, A23);    // a3 | a2 | ...
-  const __m128i C0 = _mm_unpacklo_epi32(B0, B1);  // a0 | a1 | a3 | a2
-  const __m128i C1 = _mm_unpacklo_epi32(B1, B0);  // a3 | a2 | a0 | a1
-  const __m128i D0 = _mm_madd_epi16(C0, kMult1);  // out0, out1
-  const __m128i D1 = _mm_madd_epi16(C1, kMult2);  // out2, out3
-  *out = _mm_unpacklo_epi64(D0, D1);
+  const __m128i C0 = _mm_unpacklo_epi32(B0, B1);  // a0 | a1 | a3 | a2 | ...
+  const __m128i C1 = _mm_unpacklo_epi32(B1, B0);  // a3 | a2 | a0 | a1 | ...
+  const __m128i D = _mm_unpacklo_epi64(C0, C1);   // a0 a1 a3 a2 a3 a2 a0 a1
+  *out = _mm_madd_epi16(D, kMult);
 }
 
 static void FTransformWHT(const int16_t* in, int16_t* out) {
+  // Input is 12b signed.
   __m128i row0, row1, row2, row3;
+  // Rows are 14b signed.
   FTransformWHTRow(in + 0 * 64, &row0);
   FTransformWHTRow(in + 1 * 64, &row1);
   FTransformWHTRow(in + 2 * 64, &row2);
   FTransformWHTRow(in + 3 * 64, &row3);
 
   {
+    // The a* are 15b signed.
     const __m128i a0 = _mm_add_epi32(row0, row2);
     const __m128i a1 = _mm_add_epi32(row1, row3);
     const __m128i a2 = _mm_sub_epi32(row1, row3);
     const __m128i a3 = _mm_sub_epi32(row0, row2);
-    const __m128i b0 = _mm_srai_epi32(_mm_add_epi32(a0, a1), 1);
-    const __m128i b1 = _mm_srai_epi32(_mm_add_epi32(a3, a2), 1);
-    const __m128i b2 = _mm_srai_epi32(_mm_sub_epi32(a3, a2), 1);
-    const __m128i b3 = _mm_srai_epi32(_mm_sub_epi32(a0, a1), 1);
-    const __m128i out0 = _mm_packs_epi32(b0, b1);
-    const __m128i out1 = _mm_packs_epi32(b2, b3);
-    _mm_storeu_si128((__m128i*)&out[0], out0);
-    _mm_storeu_si128((__m128i*)&out[8], out1);
+    const __m128i a0a3 = _mm_packs_epi32(a0, a3);
+    const __m128i a1a2 = _mm_packs_epi32(a1, a2);
+
+    // The b* are 16b signed.
+    const __m128i b0b1 = _mm_add_epi16(a0a3, a1a2);
+    const __m128i b3b2 = _mm_sub_epi16(a0a3, a1a2);
+    const __m128i tmp_b2b3 = _mm_unpackhi_epi64(b3b2, b3b2);
+    const __m128i b2b3 = _mm_unpacklo_epi64(tmp_b2b3, b3b2);
+
+    _mm_storeu_si128((__m128i*)&out[0], _mm_srai_epi16(b0b1, 1));
+    _mm_storeu_si128((__m128i*)&out[8], _mm_srai_epi16(b2b3, 1));
   }
 }
 
@@ -692,12 +615,10 @@ static WEBP_INLINE void TrueMotion(uint8_t* dst, const uint8_t* left,
 
 static WEBP_INLINE void DC8uv(uint8_t* dst, const uint8_t* left,
                               const uint8_t* top) {
-  const __m128i zero = _mm_setzero_si128();
   const __m128i top_values = _mm_loadl_epi64((const __m128i*)top);
   const __m128i left_values = _mm_loadl_epi64((const __m128i*)left);
-  const __m128i sum_top = _mm_sad_epu8(top_values, zero);
-  const __m128i sum_left = _mm_sad_epu8(left_values, zero);
-  const int DC = _mm_cvtsi128_si32(sum_top) + _mm_cvtsi128_si32(sum_left) + 8;
+  const __m128i combined = _mm_unpacklo_epi64(top_values, left_values);
+  const int DC = VP8HorizontalAdd8b(&combined) + 8;
   Put8x8uv(DC >> 4, dst);
 }
 
@@ -735,27 +656,16 @@ static WEBP_INLINE void DC8uvMode(uint8_t* dst, const uint8_t* left,
 
 static WEBP_INLINE void DC16(uint8_t* dst, const uint8_t* left,
                              const uint8_t* top) {
-  const __m128i zero = _mm_setzero_si128();
   const __m128i top_row = _mm_load_si128((const __m128i*)top);
   const __m128i left_row = _mm_load_si128((const __m128i*)left);
-  const __m128i sad8x2 = _mm_sad_epu8(top_row, zero);
-  // sum the two sads: sad8x2[0:1] + sad8x2[8:9]
-  const __m128i sum_top = _mm_add_epi16(sad8x2, _mm_shuffle_epi32(sad8x2, 2));
-  const __m128i sad8x2_left = _mm_sad_epu8(left_row, zero);
-  // sum the two sads: sad8x2[0:1] + sad8x2[8:9]
-  const __m128i sum_left =
-      _mm_add_epi16(sad8x2_left, _mm_shuffle_epi32(sad8x2_left, 2));
-  const int DC = _mm_cvtsi128_si32(sum_top) + _mm_cvtsi128_si32(sum_left) + 16;
+  const int DC =
+      VP8HorizontalAdd8b(&top_row) + VP8HorizontalAdd8b(&left_row) + 16;
   Put16(DC >> 5, dst);
 }
 
 static WEBP_INLINE void DC16NoLeft(uint8_t* dst, const uint8_t* top) {
-  const __m128i zero = _mm_setzero_si128();
   const __m128i top_row = _mm_load_si128((const __m128i*)top);
-  const __m128i sad8x2 = _mm_sad_epu8(top_row, zero);
-  // sum the two sads: sad8x2[0:1] + sad8x2[8:9]
-  const __m128i sum = _mm_add_epi16(sad8x2, _mm_shuffle_epi32(sad8x2, 2));
-  const int DC = _mm_cvtsi128_si32(sum) + 8;
+  const int DC = VP8HorizontalAdd8b(&top_row) + 8;
   Put16(DC >> 4, dst);
 }
 
@@ -1142,15 +1052,15 @@ static int SSE4x4(const uint8_t* a, const uint8_t* b) {
 // reconstructed samples.
 
 // Hadamard transform
-// Returns the difference between the weighted sum of the absolute value of
-// transformed coefficients.
+// Returns the weighted sum of the absolute value of transformed coefficients.
+// w[] contains a row-major 4 by 4 symmetric matrix.
 static int TTransform(const uint8_t* inA, const uint8_t* inB,
                       const uint16_t* const w) {
   int32_t sum[4];
   __m128i tmp_0, tmp_1, tmp_2, tmp_3;
   const __m128i zero = _mm_setzero_si128();
 
-  // Load, combine and transpose inputs.
+  // Load and combine inputs.
   {
     const __m128i inA_0 = _mm_loadl_epi64((const __m128i*)&inA[BPS * 0]);
     const __m128i inA_1 = _mm_loadl_epi64((const __m128i*)&inA[BPS * 1]);
@@ -1162,37 +1072,22 @@ static int TTransform(const uint8_t* inA, const uint8_t* inB,
     const __m128i inB_3 = _mm_loadl_epi64((const __m128i*)&inB[BPS * 3]);
 
     // Combine inA and inB (we'll do two transforms in parallel).
-    const __m128i inAB_0 = _mm_unpacklo_epi8(inA_0, inB_0);
-    const __m128i inAB_1 = _mm_unpacklo_epi8(inA_1, inB_1);
-    const __m128i inAB_2 = _mm_unpacklo_epi8(inA_2, inB_2);
-    const __m128i inAB_3 = _mm_unpacklo_epi8(inA_3, inB_3);
-    // a00 b00 a01 b01 a02 b03 a03 b03   0 0 0 0 0 0 0 0
-    // a10 b10 a11 b11 a12 b12 a13 b13   0 0 0 0 0 0 0 0
-    // a20 b20 a21 b21 a22 b22 a23 b23   0 0 0 0 0 0 0 0
-    // a30 b30 a31 b31 a32 b32 a33 b33   0 0 0 0 0 0 0 0
-
-    // Transpose the two 4x4, discarding the filling zeroes.
-    const __m128i transpose0_0 = _mm_unpacklo_epi8(inAB_0, inAB_2);
-    const __m128i transpose0_1 = _mm_unpacklo_epi8(inAB_1, inAB_3);
-    // a00 a20  b00 b20  a01 a21  b01 b21  a02 a22  b02 b22  a03 a23  b03 b23
-    // a10 a30  b10 b30  a11 a31  b11 b31  a12 a32  b12 b32  a13 a33  b13 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi8(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpackhi_epi8(transpose0_0, transpose0_1);
-    // a00 a10 a20 a30  b00 b10 b20 b30  a01 a11 a21 a31  b01 b11 b21 b31
-    // a02 a12 a22 a32  b02 b12 b22 b32  a03 a13 a23 a33  b03 b13 b23 b33
-
-    // Convert to 16b.
-    tmp_0 = _mm_unpacklo_epi8(transpose1_0, zero);
-    tmp_1 = _mm_unpackhi_epi8(transpose1_0, zero);
-    tmp_2 = _mm_unpacklo_epi8(transpose1_1, zero);
-    tmp_3 = _mm_unpackhi_epi8(transpose1_1, zero);
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    const __m128i inAB_0 = _mm_unpacklo_epi32(inA_0, inB_0);
+    const __m128i inAB_1 = _mm_unpacklo_epi32(inA_1, inB_1);
+    const __m128i inAB_2 = _mm_unpacklo_epi32(inA_2, inB_2);
+    const __m128i inAB_3 = _mm_unpacklo_epi32(inA_3, inB_3);
+    tmp_0 = _mm_unpacklo_epi8(inAB_0, zero);
+    tmp_1 = _mm_unpacklo_epi8(inAB_1, zero);
+    tmp_2 = _mm_unpacklo_epi8(inAB_2, zero);
+    tmp_3 = _mm_unpacklo_epi8(inAB_3, zero);
+    // a00 a01 a02 a03   b00 b01 b02 b03
+    // a10 a11 a12 a13   b10 b11 b12 b13
+    // a20 a21 a22 a23   b20 b21 b22 b23
+    // a30 a31 a32 a33   b30 b31 b32 b33
   }
 
-  // Horizontal pass and subsequent transpose.
+  // Vertical pass first to avoid a transpose (vertical and horizontal passes
+  // are commutative because w/kWeightY is symmetric) and subsequent transpose.
   {
     // Calculate a and b (two 4x4 at once).
     const __m128i a0 = _mm_add_epi16(tmp_0, tmp_2);
@@ -1209,33 +1104,10 @@ static int TTransform(const uint8_t* inA, const uint8_t* inB,
     // a30 a31 a32 a33   b30 b31 b32 b33
 
     // Transpose the two 4x4.
-    const __m128i transpose0_0 = _mm_unpacklo_epi16(b0, b1);
-    const __m128i transpose0_1 = _mm_unpacklo_epi16(b2, b3);
-    const __m128i transpose0_2 = _mm_unpackhi_epi16(b0, b1);
-    const __m128i transpose0_3 = _mm_unpackhi_epi16(b2, b3);
-    // a00 a10 a01 a11   a02 a12 a03 a13
-    // a20 a30 a21 a31   a22 a32 a23 a33
-    // b00 b10 b01 b11   b02 b12 b03 b13
-    // b20 b30 b21 b31   b22 b32 b23 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpacklo_epi32(transpose0_2, transpose0_3);
-    const __m128i transpose1_2 = _mm_unpackhi_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_3 = _mm_unpackhi_epi32(transpose0_2, transpose0_3);
-    // a00 a10 a20 a30 a01 a11 a21 a31
-    // b00 b10 b20 b30 b01 b11 b21 b31
-    // a02 a12 a22 a32 a03 a13 a23 a33
-    // b02 b12 a22 b32 b03 b13 b23 b33
-    tmp_0 = _mm_unpacklo_epi64(transpose1_0, transpose1_1);
-    tmp_1 = _mm_unpackhi_epi64(transpose1_0, transpose1_1);
-    tmp_2 = _mm_unpacklo_epi64(transpose1_2, transpose1_3);
-    tmp_3 = _mm_unpackhi_epi64(transpose1_2, transpose1_3);
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    VP8Transpose_2_4x4_16b(&b0, &b1, &b2, &b3, &tmp_0, &tmp_1, &tmp_2, &tmp_3);
   }
 
-  // Vertical pass and difference of weighted sums.
+  // Horizontal pass and difference of weighted sums.
   {
     // Load all inputs.
     const __m128i w_0 = _mm_loadu_si128((const __m128i*)&w[0]);

src/dsp/enc_sse41.c

@@ -17,6 +17,7 @@
 #include <smmintrin.h>
 #include <stdlib.h>  // for abs()
 
+#include "./common_sse2.h"
 #include "../enc/vp8enci.h"
 
 //------------------------------------------------------------------------------
@@ -67,55 +68,45 @@ static void CollectHistogram(const uint8_t* ref, const uint8_t* pred,
 // reconstructed samples.
 
 // Hadamard transform
-// Returns the difference between the weighted sum of the absolute value of
-// transformed coefficients.
+// Returns the weighted sum of the absolute value of transformed coefficients.
+// w[] contains a row-major 4 by 4 symmetric matrix.
 static int TTransform(const uint8_t* inA, const uint8_t* inB,
                       const uint16_t* const w) {
+  int32_t sum[4];
   __m128i tmp_0, tmp_1, tmp_2, tmp_3;
 
-  // Load, combine and transpose inputs.
+  // Load and combine inputs.
   {
-    const __m128i inA_0 = _mm_loadl_epi64((const __m128i*)&inA[BPS * 0]);
-    const __m128i inA_1 = _mm_loadl_epi64((const __m128i*)&inA[BPS * 1]);
-    const __m128i inA_2 = _mm_loadl_epi64((const __m128i*)&inA[BPS * 2]);
+    const __m128i inA_0 = _mm_loadu_si128((const __m128i*)&inA[BPS * 0]);
+    const __m128i inA_1 = _mm_loadu_si128((const __m128i*)&inA[BPS * 1]);
+    const __m128i inA_2 = _mm_loadu_si128((const __m128i*)&inA[BPS * 2]);
+    // In SSE4.1, with gcc 4.8 at least (maybe other versions),
+    // _mm_loadu_si128 is faster than _mm_loadl_epi64. But for the last lump
+    // of inA and inB, _mm_loadl_epi64 is still used not to have an out of
+    // bound read.
     const __m128i inA_3 = _mm_loadl_epi64((const __m128i*)&inA[BPS * 3]);
-    const __m128i inB_0 = _mm_loadl_epi64((const __m128i*)&inB[BPS * 0]);
-    const __m128i inB_1 = _mm_loadl_epi64((const __m128i*)&inB[BPS * 1]);
-    const __m128i inB_2 = _mm_loadl_epi64((const __m128i*)&inB[BPS * 2]);
+    const __m128i inB_0 = _mm_loadu_si128((const __m128i*)&inB[BPS * 0]);
+    const __m128i inB_1 = _mm_loadu_si128((const __m128i*)&inB[BPS * 1]);
+    const __m128i inB_2 = _mm_loadu_si128((const __m128i*)&inB[BPS * 2]);
     const __m128i inB_3 = _mm_loadl_epi64((const __m128i*)&inB[BPS * 3]);
 
     // Combine inA and inB (we'll do two transforms in parallel).
-    const __m128i inAB_0 = _mm_unpacklo_epi8(inA_0, inB_0);
-    const __m128i inAB_1 = _mm_unpacklo_epi8(inA_1, inB_1);
-    const __m128i inAB_2 = _mm_unpacklo_epi8(inA_2, inB_2);
-    const __m128i inAB_3 = _mm_unpacklo_epi8(inA_3, inB_3);
-    // a00 b00 a01 b01 a02 b03 a03 b03   0 0 0 0 0 0 0 0
-    // a10 b10 a11 b11 a12 b12 a13 b13   0 0 0 0 0 0 0 0
-    // a20 b20 a21 b21 a22 b22 a23 b23   0 0 0 0 0 0 0 0
-    // a30 b30 a31 b31 a32 b32 a33 b33   0 0 0 0 0 0 0 0
-
-    // Transpose the two 4x4, discarding the filling zeroes.
-    const __m128i transpose0_0 = _mm_unpacklo_epi8(inAB_0, inAB_2);
-    const __m128i transpose0_1 = _mm_unpacklo_epi8(inAB_1, inAB_3);
-    // a00 a20  b00 b20  a01 a21  b01 b21  a02 a22  b02 b22  a03 a23  b03 b23
-    // a10 a30  b10 b30  a11 a31  b11 b31  a12 a32  b12 b32  a13 a33  b13 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi8(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpackhi_epi8(transpose0_0, transpose0_1);
-    // a00 a10 a20 a30  b00 b10 b20 b30  a01 a11 a21 a31  b01 b11 b21 b31
-    // a02 a12 a22 a32  b02 b12 b22 b32  a03 a13 a23 a33  b03 b13 b23 b33
-
-    // Convert to 16b.
-    tmp_0 = _mm_cvtepu8_epi16(transpose1_0);
-    tmp_1 = _mm_cvtepu8_epi16(_mm_srli_si128(transpose1_0, 8));
-    tmp_2 = _mm_cvtepu8_epi16(transpose1_1);
-    tmp_3 = _mm_cvtepu8_epi16(_mm_srli_si128(transpose1_1, 8));
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    const __m128i inAB_0 = _mm_unpacklo_epi32(inA_0, inB_0);
+    const __m128i inAB_1 = _mm_unpacklo_epi32(inA_1, inB_1);
+    const __m128i inAB_2 = _mm_unpacklo_epi32(inA_2, inB_2);
+    const __m128i inAB_3 = _mm_unpacklo_epi32(inA_3, inB_3);
+    tmp_0 = _mm_cvtepu8_epi16(inAB_0);
+    tmp_1 = _mm_cvtepu8_epi16(inAB_1);
+    tmp_2 = _mm_cvtepu8_epi16(inAB_2);
+    tmp_3 = _mm_cvtepu8_epi16(inAB_3);
+    // a00 a01 a02 a03   b00 b01 b02 b03
+    // a10 a11 a12 a13   b10 b11 b12 b13
+    // a20 a21 a22 a23   b20 b21 b22 b23
+    // a30 a31 a32 a33   b30 b31 b32 b33
   }
 
-  // Horizontal pass and subsequent transpose.
+  // Vertical pass first to avoid a transpose (vertical and horizontal passes
+  // are commutative because w/kWeightY is symmetric) and subsequent transpose.
   {
     // Calculate a and b (two 4x4 at once).
     const __m128i a0 = _mm_add_epi16(tmp_0, tmp_2);
@@ -132,33 +123,10 @@ static int TTransform(const uint8_t* inA, const uint8_t* inB,
     // a30 a31 a32 a33   b30 b31 b32 b33
 
     // Transpose the two 4x4.
-    const __m128i transpose0_0 = _mm_unpacklo_epi16(b0, b1);
-    const __m128i transpose0_1 = _mm_unpacklo_epi16(b2, b3);
-    const __m128i transpose0_2 = _mm_unpackhi_epi16(b0, b1);
-    const __m128i transpose0_3 = _mm_unpackhi_epi16(b2, b3);
-    // a00 a10 a01 a11   a02 a12 a03 a13
-    // a20 a30 a21 a31   a22 a32 a23 a33
-    // b00 b10 b01 b11   b02 b12 b03 b13
-    // b20 b30 b21 b31   b22 b32 b23 b33
-    const __m128i transpose1_0 = _mm_unpacklo_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_1 = _mm_unpacklo_epi32(transpose0_2, transpose0_3);
-    const __m128i transpose1_2 = _mm_unpackhi_epi32(transpose0_0, transpose0_1);
-    const __m128i transpose1_3 = _mm_unpackhi_epi32(transpose0_2, transpose0_3);
-    // a00 a10 a20 a30 a01 a11 a21 a31
-    // b00 b10 b20 b30 b01 b11 b21 b31
-    // a02 a12 a22 a32 a03 a13 a23 a33
-    // b02 b12 a22 b32 b03 b13 b23 b33
-    tmp_0 = _mm_unpacklo_epi64(transpose1_0, transpose1_1);
-    tmp_1 = _mm_unpackhi_epi64(transpose1_0, transpose1_1);
-    tmp_2 = _mm_unpacklo_epi64(transpose1_2, transpose1_3);
-    tmp_3 = _mm_unpackhi_epi64(transpose1_2, transpose1_3);
-    // a00 a10 a20 a30   b00 b10 b20 b30
-    // a01 a11 a21 a31   b01 b11 b21 b31
-    // a02 a12 a22 a32   b02 b12 b22 b32
-    // a03 a13 a23 a33   b03 b13 b23 b33
+    VP8Transpose_2_4x4_16b(&b0, &b1, &b2, &b3, &tmp_0, &tmp_1, &tmp_2, &tmp_3);
   }
 
-  // Vertical pass and difference of weighted sums.
+  // Horizontal pass and difference of weighted sums.
   {
     // Load all inputs.
     const __m128i w_0 = _mm_loadu_si128((const __m128i*)&w[0]);
@@ -195,11 +163,9 @@ static int TTransform(const uint8_t* inA, const uint8_t* inB,
 
     // difference of weighted sums
     A_b2 = _mm_sub_epi32(A_b0, B_b0);
-    // cascading summation of the differences
-    B_b0 = _mm_hadd_epi32(A_b2, A_b2);
-    B_b2 = _mm_hadd_epi32(B_b0, B_b0);
-    return _mm_cvtsi128_si32(B_b2);
+    _mm_storeu_si128((__m128i*)&sum[0], A_b2);
   }
+  return sum[0] + sum[1] + sum[2] + sum[3];
 }
 
 static int Disto4x4(const uint8_t* const a, const uint8_t* const b,

src/dsp/filters.c

@@ -184,19 +184,40 @@ static void GradientFilter(const uint8_t* data, int width, int height,
 
 //------------------------------------------------------------------------------
 
-static void VerticalUnfilter(int width, int height, int stride, int row,
-                             int num_rows, uint8_t* data) {
-  DoVerticalFilter(data, width, height, stride, row, num_rows, 1, data);
+static void HorizontalUnfilter(const uint8_t* prev, const uint8_t* in,
+                               uint8_t* out, int width) {
+  uint8_t pred = (prev == NULL) ? 0 : prev[0];
+  int i;
+  for (i = 0; i < width; ++i) {
+    out[i] = pred + in[i];
+    pred = out[i];
+  }
 }
 
-static void HorizontalUnfilter(int width, int height, int stride, int row,
-                               int num_rows, uint8_t* data) {
-  DoHorizontalFilter(data, width, height, stride, row, num_rows, 1, data);
+static void VerticalUnfilter(const uint8_t* prev, const uint8_t* in,
+                             uint8_t* out, int width) {
+  if (prev == NULL) {
+    HorizontalUnfilter(NULL, in, out, width);
+  } else {
+    int i;
+    for (i = 0; i < width; ++i) out[i] = prev[i] + in[i];
+  }
 }
 
-static void GradientUnfilter(int width, int height, int stride, int row,
-                             int num_rows, uint8_t* data) {
-  DoGradientFilter(data, width, height, stride, row, num_rows, 1, data);
+static void GradientUnfilter(const uint8_t* prev, const uint8_t* in,
+                             uint8_t* out, int width) {
+  if (prev == NULL) {
+    HorizontalUnfilter(NULL, in, out, width);
+  } else {
+    uint8_t top = prev[0], top_left = top, left = top;
+    int i;
+    for (i = 0; i < width; ++i) {
+      top = prev[i];  // need to read this first, in case prev==out
+      left = in[i] + GradientPredictor(left, top, top_left);
+      top_left = top;
+      out[i] = left;
+    }
+  }
 }
 
 //------------------------------------------------------------------------------

src/dsp/filters_mips_dsp_r2.c

@@ -33,10 +33,6 @@
   assert(row >= 0 && num_rows > 0 && row + num_rows <= height);                \
   (void)height;  // Silence unused warning.
 
-// if INVERSE
-//   preds == &dst[-1] == &src[-1]
-// else
-//   preds == &src[-1] != &dst[-1]
 #define DO_PREDICT_LINE(SRC, DST, LENGTH, INVERSE) do {                        \
     const uint8_t* psrc = (uint8_t*)(SRC);                                     \
     uint8_t* pdst = (uint8_t*)(DST);                                           \
@@ -45,27 +41,28 @@
     __asm__ volatile (                                                         \
       ".set      push                                   \n\t"                  \
       ".set      noreorder                              \n\t"                  \
-      "srl       %[temp0],    %[length],    0x2         \n\t"                  \
+      "srl       %[temp0],    %[length],    2           \n\t"                  \
       "beqz      %[temp0],    4f                        \n\t"                  \
-      " andi     %[temp6],    %[length],    0x3         \n\t"                  \
+      " andi     %[temp6],    %[length],    3           \n\t"                  \
     ".if " #INVERSE "                                   \n\t"                  \
-      "lbu       %[temp1],    -1(%[src])                \n\t"                  \
     "1:                                                 \n\t"                  \
+      "lbu       %[temp1],    -1(%[dst])                \n\t"                  \
       "lbu       %[temp2],    0(%[src])                 \n\t"                  \
       "lbu       %[temp3],    1(%[src])                 \n\t"                  \
       "lbu       %[temp4],    2(%[src])                 \n\t"                  \
       "lbu       %[temp5],    3(%[src])                 \n\t"                  \
+      "addu      %[temp1],    %[temp1],     %[temp2]    \n\t"                  \
+      "addu      %[temp2],    %[temp1],     %[temp3]    \n\t"                  \
+      "addu      %[temp3],    %[temp2],     %[temp4]    \n\t"                  \
+      "addu      %[temp4],    %[temp3],     %[temp5]    \n\t"                  \
+      "sb        %[temp1],    0(%[dst])                 \n\t"                  \
+      "sb        %[temp2],    1(%[dst])                 \n\t"                  \
+      "sb        %[temp3],    2(%[dst])                 \n\t"                  \
+      "sb        %[temp4],    3(%[dst])                 \n\t"                  \
       "addiu     %[src],      %[src],       4           \n\t"                  \
       "addiu     %[temp0],    %[temp0],     -1          \n\t"                  \
-      "addu      %[temp2],    %[temp2],     %[temp1]    \n\t"                  \
-      "addu      %[temp3],    %[temp3],     %[temp2]    \n\t"                  \
-      "addu      %[temp4],    %[temp4],     %[temp3]    \n\t"                  \
-      "addu      %[temp1],    %[temp5],     %[temp4]    \n\t"                  \
-      "sb        %[temp2],    -4(%[src])                \n\t"                  \
-      "sb        %[temp3],    -3(%[src])                \n\t"                  \
-      "sb        %[temp4],    -2(%[src])                \n\t"                  \
       "bnez      %[temp0],    1b                        \n\t"                  \
-      " sb       %[temp1],    -1(%[src])                \n\t"                  \
+      " addiu    %[dst],      %[dst],       4           \n\t"                  \
     ".else                                              \n\t"                  \
     "1:                                                 \n\t"                  \
       "ulw       %[temp1],    -1(%[src])                \n\t"                  \
@@ -81,16 +78,16 @@
       "beqz      %[temp6],    3f                        \n\t"                  \
       " nop                                             \n\t"                  \
     "2:                                                 \n\t"                  \
-      "lbu       %[temp1],    -1(%[src])                \n\t"                  \
       "lbu       %[temp2],    0(%[src])                 \n\t"                  \
-      "addiu     %[src],      %[src],       1           \n\t"                  \
     ".if " #INVERSE "                                   \n\t"                  \
+      "lbu       %[temp1],    -1(%[dst])                \n\t"                  \
       "addu      %[temp3],    %[temp1],     %[temp2]    \n\t"                  \
-      "sb        %[temp3],    -1(%[src])                \n\t"                  \
     ".else                                              \n\t"                  \
+      "lbu       %[temp1],    -1(%[src])                \n\t"                  \
       "subu      %[temp3],    %[temp1],     %[temp2]    \n\t"                  \
-      "sb        %[temp3],    0(%[dst])                 \n\t"                  \
     ".endif                                             \n\t"                  \
+      "addiu     %[src],      %[src],       1           \n\t"                  \
+      "sb        %[temp3],    0(%[dst])                 \n\t"                  \
       "addiu     %[temp6],    %[temp6],     -1          \n\t"                  \
       "bnez      %[temp6],    2b                        \n\t"                  \
       " addiu    %[dst],      %[dst],       1           \n\t"                  \
@@ -105,12 +102,8 @@
   } while (0)
 
 static WEBP_INLINE void PredictLine(const uint8_t* src, uint8_t* dst,
-                                    int length, int inverse) {
-  if (inverse) {
-    DO_PREDICT_LINE(src, dst, length, 1);
-  } else {
-    DO_PREDICT_LINE(src, dst, length, 0);
-  }
+                                    int length) {
+  DO_PREDICT_LINE(src, dst, length, 0);
 }
 
 #define DO_PREDICT_LINE_VERTICAL(SRC, PRED, DST, LENGTH, INVERSE) do {         \
@@ -172,16 +165,12 @@ static WEBP_INLINE void PredictLine(const uint8_t* src, uint8_t* dst,
     );                                                                         \
   } while (0)
 
-#define PREDICT_LINE_ONE_PASS(SRC, PRED, DST, INVERSE) do {                    \
+#define PREDICT_LINE_ONE_PASS(SRC, PRED, DST) do {                             \
     int temp1, temp2, temp3;                                                   \
     __asm__ volatile (                                                         \
       "lbu       %[temp1],   0(%[src])               \n\t"                     \
       "lbu       %[temp2],   0(%[pred])              \n\t"                     \
-    ".if " #INVERSE "                                \n\t"                     \
-      "addu      %[temp3],   %[temp1],   %[temp2]    \n\t"                     \
-    ".else                                           \n\t"                     \
       "subu      %[temp3],   %[temp1],   %[temp2]    \n\t"                     \
-    ".endif                                          \n\t"                     \
       "sb        %[temp3],   0(%[dst])               \n\t"                     \
       : [temp1]"=&r"(temp1), [temp2]"=&r"(temp2), [temp3]"=&r"(temp3)          \
       : [pred]"r"((PRED)), [dst]"r"((DST)), [src]"r"((SRC))                    \
@@ -192,10 +181,10 @@ static WEBP_INLINE void PredictLine(const uint8_t* src, uint8_t* dst,
 //------------------------------------------------------------------------------
 // Horizontal filter.
 
-#define FILTER_LINE_BY_LINE(INVERSE) do {                                      \
+#define FILTER_LINE_BY_LINE do {                                               \
     while (row < last_row) {                                                   \
-      PREDICT_LINE_ONE_PASS(in, preds - stride, out, INVERSE);                 \
-      DO_PREDICT_LINE(in + 1, out + 1, width - 1, INVERSE);                    \
+      PREDICT_LINE_ONE_PASS(in, preds - stride, out);                          \
+      DO_PREDICT_LINE(in + 1, out + 1, width - 1, 0);                          \
       ++row;                                                                   \
       preds += stride;                                                         \
       in += stride;                                                            \
@@ -206,19 +195,19 @@ static WEBP_INLINE void PredictLine(const uint8_t* src, uint8_t* dst,
 static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
                                            int width, int height, int stride,
                                            int row, int num_rows,
-                                           int inverse, uint8_t* out) {
+                                           uint8_t* out) {
   const uint8_t* preds;
   const size_t start_offset = row * stride;
   const int last_row = row + num_rows;
   SANITY_CHECK(in, out);
   in += start_offset;
   out += start_offset;
-  preds = inverse ? out : in;
+  preds = in;
 
   if (row == 0) {
     // Leftmost pixel is the same as input for topmost scanline.
     out[0] = in[0];
-    PredictLine(in + 1, out + 1, width - 1, inverse);
+    PredictLine(in + 1, out + 1, width - 1);
     row = 1;
     preds += stride;
     in += stride;
@@ -226,31 +215,21 @@ static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
   }
 
   // Filter line-by-line.
-  if (inverse) {
-    FILTER_LINE_BY_LINE(1);
-  } else {
-    FILTER_LINE_BY_LINE(0);
-  }
+  FILTER_LINE_BY_LINE;
 }
-
 #undef FILTER_LINE_BY_LINE
 
 static void HorizontalFilter(const uint8_t* data, int width, int height,
                              int stride, uint8_t* filtered_data) {
-  DoHorizontalFilter(data, width, height, stride, 0, height, 0, filtered_data);
-}
-
-static void HorizontalUnfilter(int width, int height, int stride, int row,
-                               int num_rows, uint8_t* data) {
-  DoHorizontalFilter(data, width, height, stride, row, num_rows, 1, data);
+  DoHorizontalFilter(data, width, height, stride, 0, height, filtered_data);
 }
 
 //------------------------------------------------------------------------------
 // Vertical filter.
 
-#define FILTER_LINE_BY_LINE(INVERSE) do {                                      \
+#define FILTER_LINE_BY_LINE do {                                               \
     while (row < last_row) {                                                   \
-      DO_PREDICT_LINE_VERTICAL(in, preds, out, width, INVERSE);                \
+      DO_PREDICT_LINE_VERTICAL(in, preds, out, width, 0);                      \
       ++row;                                                                   \
       preds += stride;                                                         \
       in += stride;                                                            \
@@ -260,21 +239,20 @@ static void HorizontalUnfilter(int width, int height, int stride, int row,
 
 static WEBP_INLINE void DoVerticalFilter(const uint8_t* in,
                                          int width, int height, int stride,
-                                         int row, int num_rows,
-                                         int inverse, uint8_t* out) {
+                                         int row, int num_rows, uint8_t* out) {
   const uint8_t* preds;
   const size_t start_offset = row * stride;
   const int last_row = row + num_rows;
   SANITY_CHECK(in, out);
   in += start_offset;
   out += start_offset;
-  preds = inverse ? out : in;
+  preds = in;
 
   if (row == 0) {
     // Very first top-left pixel is copied.
     out[0] = in[0];
     // Rest of top scan-line is left-predicted.
-    PredictLine(in + 1, out + 1, width - 1, inverse);
+    PredictLine(in + 1, out + 1, width - 1);
     row = 1;
     in += stride;
     out += stride;
@@ -284,24 +262,13 @@ static WEBP_INLINE void DoVerticalFilter(const uint8_t* in,
   }
 
   // Filter line-by-line.
-  if (inverse) {
-    FILTER_LINE_BY_LINE(1);
-  } else {
-    FILTER_LINE_BY_LINE(0);
-  }
+  FILTER_LINE_BY_LINE;
 }
-
 #undef FILTER_LINE_BY_LINE
-#undef DO_PREDICT_LINE_VERTICAL
 
 static void VerticalFilter(const uint8_t* data, int width, int height,
                            int stride, uint8_t* filtered_data) {
-  DoVerticalFilter(data, width, height, stride, 0, height, 0, filtered_data);
-}
-
-static void VerticalUnfilter(int width, int height, int stride, int row,
-                             int num_rows, uint8_t* data) {
-  DoVerticalFilter(data, width, height, stride, row, num_rows, 1, data);
+  DoVerticalFilter(data, width, height, stride, 0, height, filtered_data);
 }
 
 //------------------------------------------------------------------------------
@@ -321,10 +288,10 @@ static WEBP_INLINE int GradientPredictor(uint8_t a, uint8_t b, uint8_t c) {
   return temp0;
 }
 
-#define FILTER_LINE_BY_LINE(INVERSE, PREDS, OPERATION) do {                    \
+#define FILTER_LINE_BY_LINE(PREDS, OPERATION) do {                             \
     while (row < last_row) {                                                   \
       int w;                                                                   \
-      PREDICT_LINE_ONE_PASS(in, PREDS - stride, out, INVERSE);                 \
+      PREDICT_LINE_ONE_PASS(in, PREDS - stride, out);                          \
       for (w = 1; w < width; ++w) {                                            \
         const int pred = GradientPredictor(PREDS[w - 1],                       \
                                            PREDS[w - stride],                  \
@@ -339,20 +306,19 @@ static WEBP_INLINE int GradientPredictor(uint8_t a, uint8_t b, uint8_t c) {
 
 static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
                                          int width, int height, int stride,
-                                         int row, int num_rows,
-                                         int inverse, uint8_t* out) {
+                                         int row, int num_rows, uint8_t* out) {
   const uint8_t* preds;
   const size_t start_offset = row * stride;
   const int last_row = row + num_rows;
   SANITY_CHECK(in, out);
   in += start_offset;
   out += start_offset;
-  preds = inverse ? out : in;
+  preds = in;
 
   // left prediction for top scan-line
   if (row == 0) {
     out[0] = in[0];
-    PredictLine(in + 1, out + 1, width - 1, inverse);
+    PredictLine(in + 1, out + 1, width - 1);
     row = 1;
     preds += stride;
     in += stride;
@@ -360,25 +326,49 @@ static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
   }
 
   // Filter line-by-line.
-  if (inverse) {
-    FILTER_LINE_BY_LINE(1, out, +);
-  } else {
-    FILTER_LINE_BY_LINE(0, in, -);
-  }
+  FILTER_LINE_BY_LINE(in, -);
 }
-
 #undef FILTER_LINE_BY_LINE
 
 static void GradientFilter(const uint8_t* data, int width, int height,
                            int stride, uint8_t* filtered_data) {
-  DoGradientFilter(data, width, height, stride, 0, height, 0, filtered_data);
+  DoGradientFilter(data, width, height, stride, 0, height, filtered_data);
 }
 
-static void GradientUnfilter(int width, int height, int stride, int row,
-                             int num_rows, uint8_t* data) {
-  DoGradientFilter(data, width, height, stride, row, num_rows, 1, data);
+//------------------------------------------------------------------------------
+
+static void HorizontalUnfilter(const uint8_t* prev, const uint8_t* in,
+                               uint8_t* out, int width) {
+ out[0] = in[0] + (prev == NULL ? 0 : prev[0]);
+ DO_PREDICT_LINE(in + 1, out + 1, width - 1, 1);
 }
 
+static void VerticalUnfilter(const uint8_t* prev, const uint8_t* in,
+                             uint8_t* out, int width) {
+  if (prev == NULL) {
+    HorizontalUnfilter(NULL, in, out, width);
+  } else {
+    DO_PREDICT_LINE_VERTICAL(in, prev, out, width, 1);
+  }
+}
+
+static void GradientUnfilter(const uint8_t* prev, const uint8_t* in,
+                             uint8_t* out, int width) {
+  if (prev == NULL) {
+    HorizontalUnfilter(NULL, in, out, width);
+  } else {
+    uint8_t top = prev[0], top_left = top, left = top;
+    int i;
+    for (i = 0; i < width; ++i) {
+      top = prev[i];  // need to read this first, in case prev==dst
+      left = in[i] + GradientPredictor(left, top, top_left);
+      top_left = top;
+      out[i] = left;
+    }
+  }
+}
+
+#undef DO_PREDICT_LINE_VERTICAL
 #undef PREDICT_LINE_ONE_PASS
 #undef DO_PREDICT_LINE
 #undef SANITY_CHECK
@@ -389,13 +379,13 @@ static void GradientUnfilter(int width, int height, int stride, int row,
 extern void VP8FiltersInitMIPSdspR2(void);
 
 WEBP_TSAN_IGNORE_FUNCTION void VP8FiltersInitMIPSdspR2(void) {
-  WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter;
-  WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter;
-  WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter;
-
   WebPUnfilters[WEBP_FILTER_HORIZONTAL] = HorizontalUnfilter;
   WebPUnfilters[WEBP_FILTER_VERTICAL] = VerticalUnfilter;
   WebPUnfilters[WEBP_FILTER_GRADIENT] = GradientUnfilter;
+
+  WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter;
+  WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter;
+  WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter;
 }
 
 #else  // !WEBP_USE_MIPS_DSP_R2

src/dsp/filters_sse2.c

@@ -33,82 +33,39 @@
   (void)height;  // Silence unused warning.
 
 static void PredictLineTop(const uint8_t* src, const uint8_t* pred,
-                           uint8_t* dst, int length, int inverse) {
+                           uint8_t* dst, int length) {
   int i;
   const int max_pos = length & ~31;
   assert(length >= 0);
-  if (inverse) {
-    for (i = 0; i < max_pos; i += 32) {
-      const __m128i A0 = _mm_loadu_si128((const __m128i*)&src[i +  0]);
-      const __m128i A1 = _mm_loadu_si128((const __m128i*)&src[i + 16]);
-      const __m128i B0 = _mm_loadu_si128((const __m128i*)&pred[i +  0]);
-      const __m128i B1 = _mm_loadu_si128((const __m128i*)&pred[i + 16]);
-      const __m128i C0 = _mm_add_epi8(A0, B0);
-      const __m128i C1 = _mm_add_epi8(A1, B1);
-      _mm_storeu_si128((__m128i*)&dst[i +  0], C0);
-      _mm_storeu_si128((__m128i*)&dst[i + 16], C1);
-    }
-    for (; i < length; ++i) dst[i] = src[i] + pred[i];
-  } else {
-    for (i = 0; i < max_pos; i += 32) {
-      const __m128i A0 = _mm_loadu_si128((const __m128i*)&src[i +  0]);
-      const __m128i A1 = _mm_loadu_si128((const __m128i*)&src[i + 16]);
-      const __m128i B0 = _mm_loadu_si128((const __m128i*)&pred[i +  0]);
-      const __m128i B1 = _mm_loadu_si128((const __m128i*)&pred[i + 16]);
-      const __m128i C0 = _mm_sub_epi8(A0, B0);
-      const __m128i C1 = _mm_sub_epi8(A1, B1);
-      _mm_storeu_si128((__m128i*)&dst[i +  0], C0);
-      _mm_storeu_si128((__m128i*)&dst[i + 16], C1);
-    }
-    for (; i < length; ++i) dst[i] = src[i] - pred[i];
+  for (i = 0; i < max_pos; i += 32) {
+    const __m128i A0 = _mm_loadu_si128((const __m128i*)&src[i +  0]);
+    const __m128i A1 = _mm_loadu_si128((const __m128i*)&src[i + 16]);
+    const __m128i B0 = _mm_loadu_si128((const __m128i*)&pred[i +  0]);
+    const __m128i B1 = _mm_loadu_si128((const __m128i*)&pred[i + 16]);
+    const __m128i C0 = _mm_sub_epi8(A0, B0);
+    const __m128i C1 = _mm_sub_epi8(A1, B1);
+    _mm_storeu_si128((__m128i*)&dst[i +  0], C0);
+    _mm_storeu_si128((__m128i*)&dst[i + 16], C1);
   }
+  for (; i < length; ++i) dst[i] = src[i] - pred[i];
 }
 
 // Special case for left-based prediction (when preds==dst-1 or preds==src-1).
-static void PredictLineLeft(const uint8_t* src, uint8_t* dst, int length,
-                            int inverse) {
+static void PredictLineLeft(const uint8_t* src, uint8_t* dst, int length) {
   int i;
-  if (length <= 0) return;
-  if (inverse) {
-    const int max_pos = length & ~7;
-    __m128i last = _mm_set_epi32(0, 0, 0, dst[-1]);
-    for (i = 0; i < max_pos; i += 8) {
-      const __m128i A0 = _mm_loadl_epi64((const __m128i*)(src + i));
-      const __m128i A1 = _mm_add_epi8(A0, last);
-      const __m128i A2 = _mm_slli_si128(A1, 1);
-      const __m128i A3 = _mm_add_epi8(A1, A2);
-      const __m128i A4 = _mm_slli_si128(A3, 2);
-      const __m128i A5 = _mm_add_epi8(A3, A4);
-      const __m128i A6 = _mm_slli_si128(A5, 4);
-      const __m128i A7 = _mm_add_epi8(A5, A6);
-      _mm_storel_epi64((__m128i*)(dst + i), A7);
-      last = _mm_srli_epi64(A7, 56);
-    }
-    for (; i < length; ++i) dst[i] = src[i] + dst[i - 1];
-  } else {
-    const int max_pos = length & ~31;
-    for (i = 0; i < max_pos; i += 32) {
-      const __m128i A0 = _mm_loadu_si128((const __m128i*)(src + i +  0    ));
-      const __m128i B0 = _mm_loadu_si128((const __m128i*)(src + i +  0 - 1));
-      const __m128i A1 = _mm_loadu_si128((const __m128i*)(src + i + 16    ));
-      const __m128i B1 = _mm_loadu_si128((const __m128i*)(src + i + 16 - 1));
-      const __m128i C0 = _mm_sub_epi8(A0, B0);
-      const __m128i C1 = _mm_sub_epi8(A1, B1);
-      _mm_storeu_si128((__m128i*)(dst + i +  0), C0);
-      _mm_storeu_si128((__m128i*)(dst + i + 16), C1);
-    }
-    for (; i < length; ++i) dst[i] = src[i] - src[i - 1];
-  }
-}
-
-static void PredictLineC(const uint8_t* src, const uint8_t* pred,
-                         uint8_t* dst, int length, int inverse) {
-  int i;
-  if (inverse) {
-    for (i = 0; i < length; ++i) dst[i] = src[i] + pred[i];
-  } else {
-    for (i = 0; i < length; ++i) dst[i] = src[i] - pred[i];
+  const int max_pos = length & ~31;
+  assert(length >= 0);
+  for (i = 0; i < max_pos; i += 32) {
+    const __m128i A0 = _mm_loadu_si128((const __m128i*)(src + i +  0    ));
+    const __m128i B0 = _mm_loadu_si128((const __m128i*)(src + i +  0 - 1));
+    const __m128i A1 = _mm_loadu_si128((const __m128i*)(src + i + 16    ));
+    const __m128i B1 = _mm_loadu_si128((const __m128i*)(src + i + 16 - 1));
+    const __m128i C0 = _mm_sub_epi8(A0, B0);
+    const __m128i C1 = _mm_sub_epi8(A1, B1);
+    _mm_storeu_si128((__m128i*)(dst + i +  0), C0);
+    _mm_storeu_si128((__m128i*)(dst + i + 16), C1);
   }
+  for (; i < length; ++i) dst[i] = src[i] - src[i - 1];
 }
 
 //------------------------------------------------------------------------------
@@ -117,21 +74,18 @@ static void PredictLineC(const uint8_t* src, const uint8_t* pred,
 static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
                                            int width, int height, int stride,
                                            int row, int num_rows,
-                                           int inverse, uint8_t* out) {
-  const uint8_t* preds;
+                                           uint8_t* out) {
   const size_t start_offset = row * stride;
   const int last_row = row + num_rows;
   SANITY_CHECK(in, out);
   in += start_offset;
   out += start_offset;
-  preds = inverse ? out : in;
 
   if (row == 0) {
     // Leftmost pixel is the same as input for topmost scanline.
     out[0] = in[0];
-    PredictLineLeft(in + 1, out + 1, width - 1, inverse);
+    PredictLineLeft(in + 1, out + 1, width - 1);
     row = 1;
-    preds += stride;
     in += stride;
     out += stride;
   }
@@ -139,10 +93,9 @@ static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
   // Filter line-by-line.
   while (row < last_row) {
     // Leftmost pixel is predicted from above.
-    PredictLineC(in, preds - stride, out, 1, inverse);
-    PredictLineLeft(in + 1, out + 1, width - 1, inverse);
+    out[0] = in[0] - in[-stride];
+    PredictLineLeft(in + 1, out + 1, width - 1);
     ++row;
-    preds += stride;
     in += stride;
     out += stride;
   }
@@ -153,34 +106,27 @@ static WEBP_INLINE void DoHorizontalFilter(const uint8_t* in,
 
 static WEBP_INLINE void DoVerticalFilter(const uint8_t* in,
                                          int width, int height, int stride,
-                                         int row, int num_rows,
-                                         int inverse, uint8_t* out) {
-  const uint8_t* preds;
+                                         int row, int num_rows, uint8_t* out) {
   const size_t start_offset = row * stride;
   const int last_row = row + num_rows;
   SANITY_CHECK(in, out);
   in += start_offset;
   out += start_offset;
-  preds = inverse ? out : in;
 
   if (row == 0) {
     // Very first top-left pixel is copied.
     out[0] = in[0];
     // Rest of top scan-line is left-predicted.
-    PredictLineLeft(in + 1, out + 1, width - 1, inverse);
+    PredictLineLeft(in + 1, out + 1, width - 1);
     row = 1;
     in += stride;
     out += stride;
-  } else {
-    // We are starting from in-between. Make sure 'preds' points to prev row.
-    preds -= stride;
   }
 
   // Filter line-by-line.
   while (row < last_row) {
-    PredictLineTop(in, preds, out, width, inverse);
+    PredictLineTop(in, in - stride, out, width);
     ++row;
-    preds += stride;
     in += stride;
     out += stride;
   }
@@ -219,6 +165,101 @@ static void GradientPredictDirect(const uint8_t* const row,
   }
 }
 
+static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
+                                         int width, int height, int stride,
+                                         int row, int num_rows,
+                                         uint8_t* out) {
+  const size_t start_offset = row * stride;
+  const int last_row = row + num_rows;
+  SANITY_CHECK(in, out);
+  in += start_offset;
+  out += start_offset;
+
+  // left prediction for top scan-line
+  if (row == 0) {
+    out[0] = in[0];
+    PredictLineLeft(in + 1, out + 1, width - 1);
+    row = 1;
+    in += stride;
+    out += stride;
+  }
+
+  // Filter line-by-line.
+  while (row < last_row) {
+    out[0] = in[0] - in[-stride];
+    GradientPredictDirect(in + 1, in + 1 - stride, out + 1, width - 1);
+    ++row;
+    in += stride;
+    out += stride;
+  }
+}
+
+#undef SANITY_CHECK
+
+//------------------------------------------------------------------------------
+
+static void HorizontalFilter(const uint8_t* data, int width, int height,
+                             int stride, uint8_t* filtered_data) {
+  DoHorizontalFilter(data, width, height, stride, 0, height, filtered_data);
+}
+
+static void VerticalFilter(const uint8_t* data, int width, int height,
+                           int stride, uint8_t* filtered_data) {
+  DoVerticalFilter(data, width, height, stride, 0, height, filtered_data);
+}
+
+static void GradientFilter(const uint8_t* data, int width, int height,
+                           int stride, uint8_t* filtered_data) {
+  DoGradientFilter(data, width, height, stride, 0, height, filtered_data);
+}
+
+//------------------------------------------------------------------------------
+// Inverse transforms
+
+static void HorizontalUnfilter(const uint8_t* prev, const uint8_t* in,
+                               uint8_t* out, int width) {
+  int i;
+  __m128i last;
+  out[0] = in[0] + (prev == NULL ? 0 : prev[0]);
+  if (width <= 1) return;
+  last = _mm_set_epi32(0, 0, 0, out[0]);
+  for (i = 1; i + 8 <= width; i += 8) {
+    const __m128i A0 = _mm_loadl_epi64((const __m128i*)(in + i));
+    const __m128i A1 = _mm_add_epi8(A0, last);
+    const __m128i A2 = _mm_slli_si128(A1, 1);
+    const __m128i A3 = _mm_add_epi8(A1, A2);
+    const __m128i A4 = _mm_slli_si128(A3, 2);
+    const __m128i A5 = _mm_add_epi8(A3, A4);
+    const __m128i A6 = _mm_slli_si128(A5, 4);
+    const __m128i A7 = _mm_add_epi8(A5, A6);
+    _mm_storel_epi64((__m128i*)(out + i), A7);
+    last = _mm_srli_epi64(A7, 56);
+  }
+  for (; i < width; ++i) out[i] = in[i] + out[i - 1];
+}
+
+static void VerticalUnfilter(const uint8_t* prev, const uint8_t* in,
+                             uint8_t* out, int width) {
+  if (prev == NULL) {
+    HorizontalUnfilter(NULL, in, out, width);
+  } else {
+    int i;
+    const int max_pos = width & ~31;
+    assert(width >= 0);
+    for (i = 0; i < max_pos; i += 32) {
+      const __m128i A0 = _mm_loadu_si128((const __m128i*)&in[i +  0]);
+      const __m128i A1 = _mm_loadu_si128((const __m128i*)&in[i + 16]);
+      const __m128i B0 = _mm_loadu_si128((const __m128i*)&prev[i +  0]);
+      const __m128i B1 = _mm_loadu_si128((const __m128i*)&prev[i + 16]);
+      const __m128i C0 = _mm_add_epi8(A0, B0);
+      const __m128i C1 = _mm_add_epi8(A1, B1);
+      _mm_storeu_si128((__m128i*)&out[i +  0], C0);
+      _mm_storeu_si128((__m128i*)&out[i + 16], C1);
+    }
+    for (; i < width; ++i) out[i] = in[i] + prev[i];
+  }
+}
+
 static void GradientPredictInverse(const uint8_t* const in,
                                    const uint8_t* const top,
                                    uint8_t* const row, int length) {
@@ -232,25 +273,24 @@ static void GradientPredictInverse(const uint8_t* const in,
       const __m128i tmp1 = _mm_loadl_epi64((const __m128i*)&top[i - 1]);
       const __m128i B = _mm_unpacklo_epi8(tmp0, zero);
       const __m128i C = _mm_unpacklo_epi8(tmp1, zero);
-      const __m128i tmp2 = _mm_loadl_epi64((const __m128i*)&in[i]);
-      const __m128i D = _mm_unpacklo_epi8(tmp2, zero);   // base input
+      const __m128i D = _mm_loadl_epi64((const __m128i*)&in[i]);  // base input
       const __m128i E = _mm_sub_epi16(B, C);  // unclipped gradient basis B - C
       __m128i out = zero;                     // accumulator for output
       __m128i mask_hi = _mm_set_epi32(0, 0, 0, 0xff);
       int k = 8;
       while (1) {
-        const __m128i tmp3 = _mm_add_epi16(A, E);        // delta = A + B - C
-        const __m128i tmp4 = _mm_min_epi16(tmp3, mask_hi);
-        const __m128i tmp5 = _mm_max_epi16(tmp4, zero);  // clipped delta
-        const __m128i tmp6 = _mm_add_epi16(tmp5, D);     // add to in[] values
-        A = _mm_and_si128(tmp6, mask_hi);                // 1-complement clip
-        out = _mm_or_si128(out, A);                      // accumulate output
+        const __m128i tmp3 = _mm_add_epi16(A, E);           // delta = A + B - C
+        const __m128i tmp4 = _mm_packus_epi16(tmp3, zero);  // saturate delta
+        const __m128i tmp5 = _mm_add_epi8(tmp4, D);         // add to in[]
+        A = _mm_and_si128(tmp5, mask_hi);                   // 1-complement clip
+        out = _mm_or_si128(out, A);                         // accumulate output
         if (--k == 0) break;
-        A = _mm_slli_si128(A, 2);                        // rotate left sample
-        mask_hi = _mm_slli_si128(mask_hi, 2);            // rotate mask
+        A = _mm_slli_si128(A, 1);                        // rotate left sample
+        mask_hi = _mm_slli_si128(mask_hi, 1);            // rotate mask
+        A = _mm_unpacklo_epi8(A, zero);                  // convert 8b->16b
       }
-      A = _mm_srli_si128(A, 14);       // prepare left sample for next iteration
-      _mm_storel_epi64((__m128i*)&row[i], _mm_packus_epi16(out, zero));
+      A = _mm_srli_si128(A, 7);       // prepare left sample for next iteration
+      _mm_storel_epi64((__m128i*)&row[i], out);
     }
     for (; i < length; ++i) {
       row[i] = in[i] + GradientPredictorC(row[i - 1], top[i], top[i - 1]);
@@ -258,76 +298,14 @@ static void GradientPredictInverse(const uint8_t* const in,
   }
 }
 
-static WEBP_INLINE void DoGradientFilter(const uint8_t* in,
-                                         int width, int height, int stride,
-                                         int row, int num_rows,
-                                         int inverse, uint8_t* out) {
-  const size_t start_offset = row * stride;
-  const int last_row = row + num_rows;
-  SANITY_CHECK(in, out);
-  in += start_offset;
-  out += start_offset;
-
-  // left prediction for top scan-line
-  if (row == 0) {
-    out[0] = in[0];
-    PredictLineLeft(in + 1, out + 1, width - 1, inverse);
-    row = 1;
-    in += stride;
-    out += stride;
+static void GradientUnfilter(const uint8_t* prev, const uint8_t* in,
+                             uint8_t* out, int width) {
+  if (prev == NULL) {
+    HorizontalUnfilter(NULL, in, out, width);
+  } else {
+    out[0] = in[0] + prev[0];  // predict from above
+    GradientPredictInverse(in + 1, prev + 1, out + 1, width - 1);
   }
-
-  // Filter line-by-line.
-  while (row < last_row) {
-    if (inverse) {
-      PredictLineC(in, out - stride, out, 1, inverse);  // predict from above
-      GradientPredictInverse(in + 1, out + 1 - stride, out + 1, width - 1);
-    } else {
-      PredictLineC(in, in - stride, out, 1, inverse);
-      GradientPredictDirect(in + 1, in + 1 - stride, out + 1, width - 1);
-    }
-    ++row;
-    in += stride;
-    out += stride;
-  }
-}
-
-#undef SANITY_CHECK
-
-//------------------------------------------------------------------------------
-
-static void HorizontalFilter(const uint8_t* data, int width, int height,
-                             int stride, uint8_t* filtered_data) {
-  DoHorizontalFilter(data, width, height, stride, 0, height, 0, filtered_data);
-}
-
-static void VerticalFilter(const uint8_t* data, int width, int height,
-                           int stride, uint8_t* filtered_data) {
-  DoVerticalFilter(data, width, height, stride, 0, height, 0, filtered_data);
-}
-
-
-static void GradientFilter(const uint8_t* data, int width, int height,
-                           int stride, uint8_t* filtered_data) {
-  DoGradientFilter(data, width, height, stride, 0, height, 0, filtered_data);
-}
-
-
-//------------------------------------------------------------------------------
-
-static void VerticalUnfilter(int width, int height, int stride, int row,
-                             int num_rows, uint8_t* data) {
-  DoVerticalFilter(data, width, height, stride, row, num_rows, 1, data);
-}
-
-static void HorizontalUnfilter(int width, int height, int stride, int row,
-                               int num_rows, uint8_t* data) {
-  DoHorizontalFilter(data, width, height, stride, row, num_rows, 1, data);
-}
-
-static void GradientUnfilter(int width, int height, int stride, int row,
-                             int num_rows, uint8_t* data) {
-  DoGradientFilter(data, width, height, stride, row, num_rows, 1, data);
 }
 
 //------------------------------------------------------------------------------

src/dsp/lossless.c

@@ -28,9 +28,7 @@
 
 // In-place sum of each component with mod 256.
 static WEBP_INLINE void AddPixelsEq(uint32_t* a, uint32_t b) {
-  const uint32_t alpha_and_green = (*a & 0xff00ff00u) + (b & 0xff00ff00u);
-  const uint32_t red_and_blue = (*a & 0x00ff00ffu) + (b & 0x00ff00ffu);
-  *a = (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu);
+  *a = VP8LAddPixels(*a, b);
 }
 
 static WEBP_INLINE uint32_t Average2(uint32_t a0, uint32_t a1) {

src/dsp/lossless.h

@@ -158,7 +158,8 @@ void VP8LCollectColorBlueTransforms_C(const uint32_t* argb, int stride,
 
 void VP8LResidualImage(int width, int height, int bits, int low_effort,
                        uint32_t* const argb, uint32_t* const argb_scratch,
-                       uint32_t* const image, int exact);
+                       uint32_t* const image, int near_lossless, int exact,
+                       int used_subtract_green);
 
 void VP8LColorSpaceTransform(int width, int height, int bits, int quality,
                              uint32_t* const argb, uint32_t* image);
@@ -172,6 +173,17 @@ static WEBP_INLINE uint32_t VP8LSubSampleSize(uint32_t size,
   return (size + (1 << sampling_bits) - 1) >> sampling_bits;
 }
 
+// Converts near lossless quality into max number of bits shaved off.
+static WEBP_INLINE int VP8LNearLosslessBits(int near_lossless_quality) {
+  //    100 -> 0
+  // 80..99 -> 1
+  // 60..79 -> 2
+  // 40..59 -> 3
+  // 20..39 -> 4
+  //  0..19 -> 5
+  return 5 - near_lossless_quality / 20;
+}
+
 // -----------------------------------------------------------------------------
 // Faster logarithm for integers. Small values use a look-up table.
 
@@ -262,6 +274,11 @@ extern VP8LHistogramAddFunc VP8LHistogramAdd;
 // -----------------------------------------------------------------------------
 // PrefixEncode()
 
+typedef int (*VP8LVectorMismatchFunc)(const uint32_t* const array1,
+                                      const uint32_t* const array2, int length);
+// Returns the first index where array1 and array2 are different.
+extern VP8LVectorMismatchFunc VP8LVectorMismatch;
+
 static WEBP_INLINE int VP8LBitsLog2Ceiling(uint32_t n) {
   const int log_floor = BitsLog2Floor(n);
   if (n == (n & ~(n - 1)))  // zero or a power of two.
@@ -324,7 +341,14 @@ static WEBP_INLINE void VP8LPrefixEncode(int distance, int* const code,
   }
 }
 
-// In-place difference of each component with mod 256.
+// Sum of each component, mod 256.
+static WEBP_INLINE uint32_t VP8LAddPixels(uint32_t a, uint32_t b) {
+  const uint32_t alpha_and_green = (a & 0xff00ff00u) + (b & 0xff00ff00u);
+  const uint32_t red_and_blue = (a & 0x00ff00ffu) + (b & 0x00ff00ffu);
+  return (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu);
+}
+
+// Difference of each component, mod 256.
 static WEBP_INLINE uint32_t VP8LSubPixels(uint32_t a, uint32_t b) {
   const uint32_t alpha_and_green =
       0x00ff00ffu + (a & 0xff00ff00u) - (b & 0xff00ff00u);

src/dsp/lossless_enc.c

@@ -382,6 +382,7 @@ static float FastLog2Slow(uint32_t v) {
 
 // Mostly used to reduce code size + readability
 static WEBP_INLINE int GetMin(int a, int b) { return (a > b) ? b : a; }
+static WEBP_INLINE int GetMax(int a, int b) { return (a < b) ? b : a; }
 
 //------------------------------------------------------------------------------
 // Methods to calculate Entropy (Shannon).
@@ -551,18 +552,204 @@ static WEBP_INLINE uint32_t Predict(VP8LPredictorFunc pred_func,
   }
 }
 
+static int MaxDiffBetweenPixels(uint32_t p1, uint32_t p2) {
+  const int diff_a = abs((int)(p1 >> 24) - (int)(p2 >> 24));
+  const int diff_r = abs((int)((p1 >> 16) & 0xff) - (int)((p2 >> 16) & 0xff));
+  const int diff_g = abs((int)((p1 >> 8) & 0xff) - (int)((p2 >> 8) & 0xff));
+  const int diff_b = abs((int)(p1 & 0xff) - (int)(p2 & 0xff));
+  return GetMax(GetMax(diff_a, diff_r), GetMax(diff_g, diff_b));
+}
+
+static int MaxDiffAroundPixel(uint32_t current, uint32_t up, uint32_t down,
+                              uint32_t left, uint32_t right) {
+  const int diff_up = MaxDiffBetweenPixels(current, up);
+  const int diff_down = MaxDiffBetweenPixels(current, down);
+  const int diff_left = MaxDiffBetweenPixels(current, left);
+  const int diff_right = MaxDiffBetweenPixels(current, right);
+  return GetMax(GetMax(diff_up, diff_down), GetMax(diff_left, diff_right));
+}
+
+static uint32_t AddGreenToBlueAndRed(uint32_t argb) {
+  const uint32_t green = (argb >> 8) & 0xff;
+  uint32_t red_blue = argb & 0x00ff00ffu;
+  red_blue += (green << 16) | green;
+  red_blue &= 0x00ff00ffu;
+  return (argb & 0xff00ff00u) | red_blue;
+}
+
+static void MaxDiffsForRow(int width, int stride, const uint32_t* const argb,
+                           uint8_t* const max_diffs, int used_subtract_green) {
+  uint32_t current, up, down, left, right;
+  int x;
+  if (width <= 2) return;
+  current = argb[0];
+  right = argb[1];
+  if (used_subtract_green) {
+    current = AddGreenToBlueAndRed(current);
+    right = AddGreenToBlueAndRed(right);
+  }
+  // max_diffs[0] and max_diffs[width - 1] are never used.
+  for (x = 1; x < width - 1; ++x) {
+    up = argb[-stride + x];
+    down = argb[stride + x];
+    left = current;
+    current = right;
+    right = argb[x + 1];
+    if (used_subtract_green) {
+      up = AddGreenToBlueAndRed(up);
+      down = AddGreenToBlueAndRed(down);
+      right = AddGreenToBlueAndRed(right);
+    }
+    max_diffs[x] = MaxDiffAroundPixel(current, up, down, left, right);
+  }
+}
+
+// Quantize the difference between the actual component value and its prediction
+// to a multiple of quantization, working modulo 256, taking care not to cross
+// a boundary (inclusive upper limit).
+static uint8_t NearLosslessComponent(uint8_t value, uint8_t predict,
+                                     uint8_t boundary, int quantization) {
+  const int residual = (value - predict) & 0xff;
+  const int boundary_residual = (boundary - predict) & 0xff;
+  const int lower = residual & ~(quantization - 1);
+  const int upper = lower + quantization;
+  // Resolve ties towards a value closer to the prediction (i.e. towards lower
+  // if value comes after prediction and towards upper otherwise).
+  const int bias = ((boundary - value) & 0xff) < boundary_residual;
+  if (residual - lower < upper - residual + bias) {
+    // lower is closer to residual than upper.
+    if (residual > boundary_residual && lower <= boundary_residual) {
+      // Halve quantization step to avoid crossing boundary. This midpoint is
+      // on the same side of boundary as residual because midpoint >= residual
+      // (since lower is closer than upper) and residual is above the boundary.
+      return lower + (quantization >> 1);
+    }
+    return lower;
+  } else {
+    // upper is closer to residual than lower.
+    if (residual <= boundary_residual && upper > boundary_residual) {
+      // Halve quantization step to avoid crossing boundary. This midpoint is
+      // on the same side of boundary as residual because midpoint <= residual
+      // (since upper is closer than lower) and residual is below the boundary.
+      return lower + (quantization >> 1);
+    }
+    return upper & 0xff;
+  }
+}
+
+// Quantize every component of the difference between the actual pixel value and
+// its prediction to a multiple of a quantization (a power of 2, not larger than
+// max_quantization which is a power of 2, smaller than max_diff). Take care if
+// value and predict have undergone subtract green, which means that red and
+// blue are represented as offsets from green.
+static uint32_t NearLossless(uint32_t value, uint32_t predict,
+                             int max_quantization, int max_diff,
+                             int used_subtract_green) {
+  int quantization;
+  uint8_t new_green = 0;
+  uint8_t green_diff = 0;
+  uint8_t a, r, g, b;
+  if (max_diff <= 2) {
+    return VP8LSubPixels(value, predict);
+  }
+  quantization = max_quantization;
+  while (quantization >= max_diff) {
+    quantization >>= 1;
+  }
+  if ((value >> 24) == 0 || (value >> 24) == 0xff) {
+    // Preserve transparency of fully transparent or fully opaque pixels.
+    a = ((value >> 24) - (predict >> 24)) & 0xff;
+  } else {
+    a = NearLosslessComponent(value >> 24, predict >> 24, 0xff, quantization);
+  }
+  g = NearLosslessComponent((value >> 8) & 0xff, (predict >> 8) & 0xff, 0xff,
+                            quantization);
+  if (used_subtract_green) {
+    // The green offset will be added to red and blue components during decoding
+    // to obtain the actual red and blue values.
+    new_green = ((predict >> 8) + g) & 0xff;
+    // The amount by which green has been adjusted during quantization. It is
+    // subtracted from red and blue for compensation, to avoid accumulating two
+    // quantization errors in them.
+    green_diff = (new_green - (value >> 8)) & 0xff;
+  }
+  r = NearLosslessComponent(((value >> 16) - green_diff) & 0xff,
+                            (predict >> 16) & 0xff, 0xff - new_green,
+                            quantization);
+  b = NearLosslessComponent((value - green_diff) & 0xff, predict & 0xff,
+                            0xff - new_green, quantization);
+  return ((uint32_t)a << 24) | ((uint32_t)r << 16) | ((uint32_t)g << 8) | b;
+}
+
+// Returns the difference between the pixel and its prediction. In case of a
+// lossy encoding, updates the source image to avoid propagating the deviation
+// further to pixels which depend on the current pixel for their predictions.
+static WEBP_INLINE uint32_t GetResidual(int width, int height,
+                                        uint32_t* const upper_row,
+                                        uint32_t* const current_row,
+                                        const uint8_t* const max_diffs,
+                                        int mode, VP8LPredictorFunc pred_func,
+                                        int x, int y, int max_quantization,
+                                        int exact, int used_subtract_green) {
+  const uint32_t predict = Predict(pred_func, x, y, current_row, upper_row);
+  uint32_t residual;
+  if (max_quantization == 1 || mode == 0 || y == 0 || y == height - 1 ||
+      x == 0 || x == width - 1) {
+    residual = VP8LSubPixels(current_row[x], predict);
+  } else {
+    residual = NearLossless(current_row[x], predict, max_quantization,
+                            max_diffs[x], used_subtract_green);
+    // Update the source image.
+    current_row[x] = VP8LAddPixels(predict, residual);
+    // x is never 0 here so we do not need to update upper_row like below.
+  }
+  if (!exact && (current_row[x] & kMaskAlpha) == 0) {
+    // If alpha is 0, cleanup RGB. We can choose the RGB values of the residual
+    // for best compression. The prediction of alpha itself can be non-zero and
+    // must be kept though. We choose RGB of the residual to be 0.
+    residual &= kMaskAlpha;
+    // Update the source image.
+    current_row[x] = predict & ~kMaskAlpha;
+    // The prediction for the rightmost pixel in a row uses the leftmost pixel
+    // in that row as its top-right context pixel. Hence if we change the
+    // leftmost pixel of current_row, the corresponding change must be applied
+    // to upper_row as well where top-right context is being read from.
+    if (x == 0 && y != 0) upper_row[width] = current_row[0];
+  }
+  return residual;
+}
+
 // Returns best predictor and updates the accumulated histogram.
+// If max_quantization > 1, assumes that near lossless processing will be
+// applied, quantizing residuals to multiples of quantization levels up to
+// max_quantization (the actual quantization level depends on smoothness near
+// the given pixel).
 static int GetBestPredictorForTile(int width, int height,
                                    int tile_x, int tile_y, int bits,
                                    int accumulated[4][256],
-                                   const uint32_t* const argb_scratch,
-                                   int exact) {
+                                   uint32_t* const argb_scratch,
+                                   const uint32_t* const argb,
+                                   int max_quantization,
+                                   int exact, int used_subtract_green) {
   const int kNumPredModes = 14;
-  const int col_start = tile_x << bits;
-  const int row_start = tile_y << bits;
+  const int start_x = tile_x << bits;
+  const int start_y = tile_y << bits;
   const int tile_size = 1 << bits;
-  const int max_y = GetMin(tile_size, height - row_start);
-  const int max_x = GetMin(tile_size, width - col_start);
+  const int max_y = GetMin(tile_size, height - start_y);
+  const int max_x = GetMin(tile_size, width - start_x);
+  // Whether there exist columns just outside the tile.
+  const int have_left = (start_x > 0);
+  const int have_right = (max_x < width - start_x);
+  // Position and size of the strip covering the tile and adjacent columns if
+  // they exist.
+  const int context_start_x = start_x - have_left;
+  const int context_width = max_x + have_left + have_right;
+  // The width of upper_row and current_row is one pixel larger than image width
+  // to allow the top right pixel to point to the leftmost pixel of the next row
+  // when at the right edge.
+  uint32_t* upper_row = argb_scratch;
+  uint32_t* current_row = upper_row + width + 1;
+  uint8_t* const max_diffs = (uint8_t*)(current_row + width + 1);
   float best_diff = MAX_DIFF_COST;
   int best_mode = 0;
   int mode;
@@ -571,28 +758,46 @@ static int GetBestPredictorForTile(int width, int height,
   // Need pointers to be able to swap arrays.
   int (*histo_argb)[256] = histo_stack_1;
   int (*best_histo)[256] = histo_stack_2;
-
   int i, j;
+
   for (mode = 0; mode < kNumPredModes; ++mode) {
-    const uint32_t* current_row = argb_scratch;
     const VP8LPredictorFunc pred_func = VP8LPredictors[mode];
     float cur_diff;
-    int y;
+    int relative_y;
     memset(histo_argb, 0, sizeof(histo_stack_1));
-    for (y = 0; y < max_y; ++y) {
-      int x;
-      const int row = row_start + y;
-      const uint32_t* const upper_row = current_row;
-      current_row = upper_row + width;
-      for (x = 0; x < max_x; ++x) {
-        const int col = col_start + x;
-        const uint32_t predict =
-            Predict(pred_func, col, row, current_row, upper_row);
-        uint32_t residual = VP8LSubPixels(current_row[col], predict);
-        if (!exact && (current_row[col] & kMaskAlpha) == 0) {
-          residual &= kMaskAlpha;  // See CopyTileWithPrediction.
-        }
-        UpdateHisto(histo_argb, residual);
+    if (start_y > 0) {
+      // Read the row above the tile which will become the first upper_row.
+      // Include a pixel to the left if it exists; include a pixel to the right
+      // in all cases (wrapping to the leftmost pixel of the next row if it does
+      // not exist).
+      memcpy(current_row + context_start_x,
+             argb + (start_y - 1) * width + context_start_x,
+             sizeof(*argb) * (max_x + have_left + 1));
+    }
+    for (relative_y = 0; relative_y < max_y; ++relative_y) {
+      const int y = start_y + relative_y;
+      int relative_x;
+      uint32_t* tmp = upper_row;
+      upper_row = current_row;
+      current_row = tmp;
+      // Read current_row. Include a pixel to the left if it exists; include a
+      // pixel to the right in all cases except at the bottom right corner of
+      // the image (wrapping to the leftmost pixel of the next row if it does
+      // not exist in the current row).
+      memcpy(current_row + context_start_x,
+             argb + y * width + context_start_x,
+             sizeof(*argb) * (max_x + have_left + (y + 1 < height)));
+      if (max_quantization > 1 && y >= 1 && y + 1 < height) {
+        MaxDiffsForRow(context_width, width, argb + y * width + context_start_x,
+                       max_diffs + context_start_x, used_subtract_green);
+      }
+
+      for (relative_x = 0; relative_x < max_x; ++relative_x) {
+        const int x = start_x + relative_x;
+        UpdateHisto(histo_argb,
+                    GetResidual(width, height, upper_row, current_row,
+                                max_diffs, mode, pred_func, x, y,
+                                max_quantization, exact, used_subtract_green));
       }
     }
     cur_diff = PredictionCostSpatialHistogram(
@@ -615,71 +820,82 @@ static int GetBestPredictorForTile(int width, int height,
   return best_mode;
 }
 
+// Converts pixels of the image to residuals with respect to predictions.
+// If max_quantization > 1, applies near lossless processing, quantizing
+// residuals to multiples of quantization levels up to max_quantization
+// (the actual quantization level depends on smoothness near the given pixel).
 static void CopyImageWithPrediction(int width, int height,
                                     int bits, uint32_t* const modes,
                                     uint32_t* const argb_scratch,
                                     uint32_t* const argb,
-                                    int low_effort, int exact) {
+                                    int low_effort, int max_quantization,
+                                    int exact, int used_subtract_green) {
   const int tiles_per_row = VP8LSubSampleSize(width, bits);
   const int mask = (1 << bits) - 1;
-  // The row size is one pixel longer to allow the top right pixel to point to
-  // the leftmost pixel of the next row when at the right edge.
-  uint32_t* current_row = argb_scratch;
-  uint32_t* upper_row = argb_scratch + width + 1;
+  // The width of upper_row and current_row is one pixel larger than image width
+  // to allow the top right pixel to point to the leftmost pixel of the next row
+  // when at the right edge.
+  uint32_t* upper_row = argb_scratch;
+  uint32_t* current_row = upper_row + width + 1;
+  uint8_t* current_max_diffs = (uint8_t*)(current_row + width + 1);
+  uint8_t* lower_max_diffs = current_max_diffs + width;
   int y;
-  VP8LPredictorFunc pred_func =
-      low_effort ? VP8LPredictors[kPredLowEffort] : NULL;
+  int mode = 0;
+  VP8LPredictorFunc pred_func = NULL;
 
   for (y = 0; y < height; ++y) {
     int x;
-    uint32_t* tmp = upper_row;
+    uint32_t* const tmp32 = upper_row;
     upper_row = current_row;
-    current_row = tmp;
-    memcpy(current_row, argb + y * width, sizeof(*current_row) * width);
-    current_row[width] = (y + 1 < height) ? argb[(y + 1) * width] : ARGB_BLACK;
+    current_row = tmp32;
+    memcpy(current_row, argb + y * width,
+           sizeof(*argb) * (width + (y + 1 < height)));
 
     if (low_effort) {
       for (x = 0; x < width; ++x) {
-        const uint32_t predict =
-            Predict(pred_func, x, y, current_row, upper_row);
+        const uint32_t predict = Predict(VP8LPredictors[kPredLowEffort], x, y,
+                                         current_row, upper_row);
         argb[y * width + x] = VP8LSubPixels(current_row[x], predict);
       }
     } else {
+      if (max_quantization > 1) {
+        // Compute max_diffs for the lower row now, because that needs the
+        // contents of argb for the current row, which we will overwrite with
+        // residuals before proceeding with the next row.
+        uint8_t* const tmp8 = current_max_diffs;
+        current_max_diffs = lower_max_diffs;
+        lower_max_diffs = tmp8;
+        if (y + 2 < height) {
+          MaxDiffsForRow(width, width, argb + (y + 1) * width, lower_max_diffs,
+                         used_subtract_green);
+        }
+      }
       for (x = 0; x < width; ++x) {
-        uint32_t predict, residual;
         if ((x & mask) == 0) {
-          const int mode =
-              (modes[(y >> bits) * tiles_per_row + (x >> bits)] >> 8) & 0xff;
+          mode = (modes[(y >> bits) * tiles_per_row + (x >> bits)] >> 8) & 0xff;
           pred_func = VP8LPredictors[mode];
         }
-        predict = Predict(pred_func, x, y, current_row, upper_row);
-        residual = VP8LSubPixels(current_row[x], predict);
-        if (!exact && (current_row[x] & kMaskAlpha) == 0) {
-          // If alpha is 0, cleanup RGB. We can choose the RGB values of the
-          // residual for best compression. The prediction of alpha itself can
-          // be non-zero and must be kept though. We choose RGB of the residual
-          // to be 0.
-          residual &= kMaskAlpha;
-          // Update input image so that next predictions use correct RGB value.
-          current_row[x] = predict & ~kMaskAlpha;
-          if (x == 0 && y != 0) upper_row[width] = current_row[x];
-        }
-        argb[y * width + x] = residual;
+        argb[y * width + x] = GetResidual(
+            width, height, upper_row, current_row, current_max_diffs, mode,
+            pred_func, x, y, max_quantization, exact, used_subtract_green);
       }
     }
   }
 }
 
+// Finds the best predictor for each tile, and converts the image to residuals
+// with respect to predictions. If near_lossless_quality < 100, applies
+// near lossless processing, shaving off more bits of residuals for lower
+// qualities.
 void VP8LResidualImage(int width, int height, int bits, int low_effort,
                        uint32_t* const argb, uint32_t* const argb_scratch,
-                       uint32_t* const image, int exact) {
-  const int max_tile_size = 1 << bits;
+                       uint32_t* const image, int near_lossless_quality,
+                       int exact, int used_subtract_green) {
   const int tiles_per_row = VP8LSubSampleSize(width, bits);
   const int tiles_per_col = VP8LSubSampleSize(height, bits);
-  uint32_t* const upper_row = argb_scratch;
-  uint32_t* const current_tile_rows = argb_scratch + width;
   int tile_y;
   int histo[4][256];
+  const int max_quantization = 1 << VP8LNearLosslessBits(near_lossless_quality);
   if (low_effort) {
     int i;
     for (i = 0; i < tiles_per_row * tiles_per_col; ++i) {
@@ -688,26 +904,19 @@ void VP8LResidualImage(int width, int height, int bits, int low_effort,
   } else {
     memset(histo, 0, sizeof(histo));
     for (tile_y = 0; tile_y < tiles_per_col; ++tile_y) {
-      const int tile_y_offset = tile_y * max_tile_size;
-      const int this_tile_height =
-          (tile_y < tiles_per_col - 1) ? max_tile_size : height - tile_y_offset;
       int tile_x;
-      if (tile_y > 0) {
-        memcpy(upper_row, current_tile_rows + (max_tile_size - 1) * width,
-               width * sizeof(*upper_row));
-      }
-      memcpy(current_tile_rows, &argb[tile_y_offset * width],
-             this_tile_height * width * sizeof(*current_tile_rows));
       for (tile_x = 0; tile_x < tiles_per_row; ++tile_x) {
         const int pred = GetBestPredictorForTile(width, height, tile_x, tile_y,
-            bits, (int (*)[256])histo, argb_scratch, exact);
+            bits, histo, argb_scratch, argb, max_quantization, exact,
+            used_subtract_green);
         image[tile_y * tiles_per_row + tile_x] = ARGB_BLACK | (pred << 8);
       }
     }
   }
 
-  CopyImageWithPrediction(width, height, bits,
-                          image, argb_scratch, argb, low_effort, exact);
+  CopyImageWithPrediction(width, height, bits, image, argb_scratch, argb,
+                          low_effort, max_quantization, exact,
+                          used_subtract_green);
 }
 
 void VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels) {
@@ -1053,6 +1262,17 @@ void VP8LColorSpaceTransform(int width, int height, int bits, int quality,
 }
 
 //------------------------------------------------------------------------------
+
+static int VectorMismatch(const uint32_t* const array1,
+                          const uint32_t* const array2, int length) {
+  int match_len = 0;
+
+  while (match_len < length && array1[match_len] == array2[match_len]) {
+    ++match_len;
+  }
+  return match_len;
+}
+
 // Bundles multiple (1, 2, 4 or 8) pixels into a single pixel.
 void VP8LBundleColorMap(const uint8_t* const row, int width,
                         int xbits, uint32_t* const dst) {
@@ -1149,6 +1369,8 @@ GetEntropyUnrefinedHelperFunc VP8LGetEntropyUnrefinedHelper;
 
 VP8LHistogramAddFunc VP8LHistogramAdd;
 
+VP8LVectorMismatchFunc VP8LVectorMismatch;
+
 extern void VP8LEncDspInitSSE2(void);
 extern void VP8LEncDspInitSSE41(void);
 extern void VP8LEncDspInitNEON(void);
@@ -1181,6 +1403,8 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInit(void) {
 
   VP8LHistogramAdd = HistogramAdd;
 
+  VP8LVectorMismatch = VectorMismatch;
+
   // If defined, use CPUInfo() to overwrite some pointers with faster versions.
   if (VP8GetCPUInfo != NULL) {
 #if defined(WEBP_USE_SSE2)

src/dsp/lossless_enc_sse2.c

@@ -324,6 +324,57 @@ static float CombinedShannonEntropy(const int X[256], const int Y[256]) {
 #undef ANALYZE_X_OR_Y
 #undef ANALYZE_XY
 
+//------------------------------------------------------------------------------
+
+static int VectorMismatch(const uint32_t* const array1,
+                          const uint32_t* const array2, int length) {
+  int match_len;
+
+  if (length >= 12) {
+    __m128i A0 = _mm_loadu_si128((const __m128i*)&array1[0]);
+    __m128i A1 = _mm_loadu_si128((const __m128i*)&array2[0]);
+    match_len = 0;
+    do {
+      // Loop unrolling and early load both provide a speedup of 10% for the
+      // current function. Also, max_limit can be MAX_LENGTH=4096 at most.
+      const __m128i cmpA = _mm_cmpeq_epi32(A0, A1);
+      const __m128i B0 =
+          _mm_loadu_si128((const __m128i*)&array1[match_len + 4]);
+      const __m128i B1 =
+          _mm_loadu_si128((const __m128i*)&array2[match_len + 4]);
+      if (_mm_movemask_epi8(cmpA) != 0xffff) break;
+      match_len += 4;
+
+      {
+        const __m128i cmpB = _mm_cmpeq_epi32(B0, B1);
+        A0 = _mm_loadu_si128((const __m128i*)&array1[match_len + 4]);
+        A1 = _mm_loadu_si128((const __m128i*)&array2[match_len + 4]);
+        if (_mm_movemask_epi8(cmpB) != 0xffff) break;
+        match_len += 4;
+      }
+    } while (match_len + 12 < length);
+  } else {
+    match_len = 0;
+    // Unroll the potential first two loops.
+    if (length >= 4 &&
+        _mm_movemask_epi8(_mm_cmpeq_epi32(
+            _mm_loadu_si128((const __m128i*)&array1[0]),
+            _mm_loadu_si128((const __m128i*)&array2[0]))) == 0xffff) {
+      match_len = 4;
+      if (length >= 8 &&
+          _mm_movemask_epi8(_mm_cmpeq_epi32(
+              _mm_loadu_si128((const __m128i*)&array1[4]),
+              _mm_loadu_si128((const __m128i*)&array2[4]))) == 0xffff)
+        match_len = 8;
+    }
+  }
+
+  while (match_len < length && array1[match_len] == array2[match_len]) {
+    ++match_len;
+  }
+  return match_len;
+}
+
 //------------------------------------------------------------------------------
 // Entry point
 
@@ -336,6 +387,7 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitSSE2(void) {
   VP8LCollectColorRedTransforms = CollectColorRedTransforms;
   VP8LHistogramAdd = HistogramAdd;
   VP8LCombinedShannonEntropy = CombinedShannonEntropy;
+  VP8LVectorMismatch = VectorMismatch;
 }
 
 #else  // !WEBP_USE_SSE2

src/dsp/msa_macro.h

@@ -0,0 +1,555 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+// MSA common macros
+//
+// Author(s):  Prashant Patil   (prashant.patil@imgtec.com)
+
+#ifndef WEBP_DSP_MSA_MACRO_H_
+#define WEBP_DSP_MSA_MACRO_H_
+
+#include <stdint.h>
+#include <msa.h>
+
+#if defined(__clang__)
+  #define CLANG_BUILD
+#endif
+
+#ifdef CLANG_BUILD
+  #define ADDVI_H(a, b)  __msa_addvi_h((v8i16)a, b)
+  #define SRAI_H(a, b)  __msa_srai_h((v8i16)a, b)
+  #define SRAI_W(a, b)  __msa_srai_w((v4i32)a, b)
+#else
+  #define ADDVI_H(a, b)  (a + b)
+  #define SRAI_H(a, b)  (a >> b)
+  #define SRAI_W(a, b)  (a >> b)
+#endif
+
+#define LD_B(RTYPE, psrc) *((RTYPE*)(psrc))
+#define LD_UB(...) LD_B(v16u8, __VA_ARGS__)
+#define LD_SB(...) LD_B(v16i8, __VA_ARGS__)
+
+#define LD_H(RTYPE, psrc) *((RTYPE*)(psrc))
+#define LD_UH(...) LD_H(v8u16, __VA_ARGS__)
+#define LD_SH(...) LD_H(v8i16, __VA_ARGS__)
+
+#define LD_W(RTYPE, psrc) *((RTYPE*)(psrc))
+#define LD_UW(...) LD_W(v4u32, __VA_ARGS__)
+#define LD_SW(...) LD_W(v4i32, __VA_ARGS__)
+
+#define ST_B(RTYPE, in, pdst) *((RTYPE*)(pdst)) = in
+#define ST_UB(...) ST_B(v16u8, __VA_ARGS__)
+#define ST_SB(...) ST_B(v16i8, __VA_ARGS__)
+
+#define ST_H(RTYPE, in, pdst) *((RTYPE*)(pdst)) = in
+#define ST_UH(...) ST_H(v8u16, __VA_ARGS__)
+#define ST_SH(...) ST_H(v8i16, __VA_ARGS__)
+
+#define ST_W(RTYPE, in, pdst) *((RTYPE*)(pdst)) = in
+#define ST_UW(...) ST_W(v4u32, __VA_ARGS__)
+#define ST_SW(...) ST_W(v4i32, __VA_ARGS__)
+
+#define MSA_LOAD_FUNC(TYPE, INSTR, FUNC_NAME)             \
+  static inline TYPE FUNC_NAME(const void* const psrc) {  \
+    const uint8_t* const psrc_m = (const uint8_t*)psrc;   \
+    TYPE val_m;                                           \
+    asm volatile (                                        \
+      "" #INSTR " %[val_m], %[psrc_m]  \n\t"              \
+      : [val_m] "=r" (val_m)                              \
+      : [psrc_m] "m" (*psrc_m));                          \
+    return val_m;                                         \
+  }
+
+#define MSA_LOAD(psrc, FUNC_NAME)  FUNC_NAME(psrc)
+
+#define MSA_STORE_FUNC(TYPE, INSTR, FUNC_NAME)               \
+  static inline void FUNC_NAME(TYPE val, void* const pdst) { \
+    uint8_t* const pdst_m = (uint8_t*)pdst;                  \
+    TYPE val_m = val;                                        \
+    asm volatile (                                           \
+      " " #INSTR "  %[val_m],  %[pdst_m]  \n\t"              \
+      : [pdst_m] "=m" (*pdst_m)                              \
+      : [val_m] "r" (val_m));                                \
+  }
+
+#define MSA_STORE(val, pdst, FUNC_NAME)  FUNC_NAME(val, pdst)
+
+#if (__mips_isa_rev >= 6)
+  MSA_LOAD_FUNC(uint16_t, lh, msa_lh);
+  #define LH(psrc)  MSA_LOAD(psrc, msa_lh)
+  MSA_LOAD_FUNC(uint32_t, lw, msa_lw);
+  #define LW(psrc)  MSA_LOAD(psrc, msa_lw)
+  #if (__mips == 64)
+    MSA_LOAD_FUNC(uint64_t, ld, msa_ld);
+    #define LD(psrc)  MSA_LOAD(psrc, msa_ld)
+  #else  // !(__mips == 64)
+    #define LD(psrc)  ((((uint64_t)MSA_LOAD(psrc + 4, msa_lw)) << 32) | \
+                       MSA_LOAD(psrc, msa_lw))
+  #endif  // (__mips == 64)
+
+  MSA_STORE_FUNC(uint16_t, sh, msa_sh);
+  #define SH(val, pdst)  MSA_STORE(val, pdst, msa_sh)
+  MSA_STORE_FUNC(uint32_t, sw, msa_sw);
+  #define SW(val, pdst)  MSA_STORE(val, pdst, msa_sw)
+  MSA_STORE_FUNC(uint64_t, sd, msa_sd);
+  #define SD(val, pdst)  MSA_STORE(val, pdst, msa_sd)
+#else  // !(__mips_isa_rev >= 6)
+  MSA_LOAD_FUNC(uint16_t, ulh, msa_ulh);
+  #define LH(psrc)  MSA_LOAD(psrc, msa_ulh)
+  MSA_LOAD_FUNC(uint32_t, ulw, msa_ulw);
+  #define LW(psrc)  MSA_LOAD(psrc, msa_ulw)
+  #if (__mips == 64)
+    MSA_LOAD_FUNC(uint64_t, uld, msa_uld);
+    #define LD(psrc)  MSA_LOAD(psrc, msa_uld)
+  #else  // !(__mips == 64)
+    #define LD(psrc)  ((((uint64_t)MSA_LOAD(psrc + 4, msa_ulw)) << 32) | \
+                        MSA_LOAD(psrc, msa_ulw))
+  #endif  // (__mips == 64)
+
+  MSA_STORE_FUNC(uint16_t, ush, msa_ush);
+  #define SH(val, pdst)  MSA_STORE(val, pdst, msa_ush)
+  MSA_STORE_FUNC(uint32_t, usw, msa_usw);
+  #define SW(val, pdst)  MSA_STORE(val, pdst, msa_usw)
+  #define SD(val, pdst) {                                                  \
+    uint8_t* const pdst_sd_m = (uint8_t*)(pdst);                           \
+    const uint32_t val0_m = (uint32_t)(val & 0x00000000FFFFFFFF);          \
+    const uint32_t val1_m = (uint32_t)((val >> 32) & 0x00000000FFFFFFFF);  \
+    SW(val0_m, pdst_sd_m);                                                 \
+    SW(val1_m, pdst_sd_m + 4);                                             \
+  }
+#endif  // (__mips_isa_rev >= 6)
+
+/* Description : Load 4 words with stride
+ * Arguments   : Inputs  - psrc, stride
+ *               Outputs - out0, out1, out2, out3
+ * Details     : Load word in 'out0' from (psrc)
+ *               Load word in 'out1' from (psrc + stride)
+ *               Load word in 'out2' from (psrc + 2 * stride)
+ *               Load word in 'out3' from (psrc + 3 * stride)
+ */
+#define LW4(psrc, stride, out0, out1, out2, out3) {  \
+  const uint8_t* ptmp = (const uint8_t*)psrc;        \
+  out0 = LW(ptmp);                                   \
+  ptmp += stride;                                    \
+  out1 = LW(ptmp);                                   \
+  ptmp += stride;                                    \
+  out2 = LW(ptmp);                                   \
+  ptmp += stride;                                    \
+  out3 = LW(ptmp);                                   \
+}
+
+/* Description : Store 4 words with stride
+ * Arguments   : Inputs - in0, in1, in2, in3, pdst, stride
+ * Details     : Store word from 'in0' to (pdst)
+ *               Store word from 'in1' to (pdst + stride)
+ *               Store word from 'in2' to (pdst + 2 * stride)
+ *               Store word from 'in3' to (pdst + 3 * stride)
+ */
+#define SW4(in0, in1, in2, in3, pdst, stride) {  \
+  uint8_t* ptmp = (uint8_t*)pdst;                \
+  SW(in0, ptmp);                                 \
+  ptmp += stride;                                \
+  SW(in1, ptmp);                                 \
+  ptmp += stride;                                \
+  SW(in2, ptmp);                                 \
+  ptmp += stride;                                \
+  SW(in3, ptmp);                                 \
+}
+
+/* Description : Load vectors with 16 byte elements with stride
+ * Arguments   : Inputs  - psrc, stride
+ *               Outputs - out0, out1
+ *               Return Type - as per RTYPE
+ * Details     : Load 16 byte elements in 'out0' from (psrc)
+ *               Load 16 byte elements in 'out1' from (psrc + stride)
+ */
+#define LD_B2(RTYPE, psrc, stride, out0, out1) {  \
+  out0 = LD_B(RTYPE, psrc);                       \
+  out1 = LD_B(RTYPE, psrc + stride);              \
+}
+#define LD_UB2(...) LD_B2(v16u8, __VA_ARGS__)
+#define LD_SB2(...) LD_B2(v16i8, __VA_ARGS__)
+
+#define LD_B4(RTYPE, psrc, stride, out0, out1, out2, out3) {  \
+  LD_B2(RTYPE, psrc, stride, out0, out1);                     \
+  LD_B2(RTYPE, psrc + 2 * stride , stride, out2, out3);       \
+}
+#define LD_UB4(...) LD_B4(v16u8, __VA_ARGS__)
+#define LD_SB4(...) LD_B4(v16i8, __VA_ARGS__)
+
+/* Description : Load vectors with 8 halfword elements with stride
+ * Arguments   : Inputs  - psrc, stride
+ *               Outputs - out0, out1
+ * Details     : Load 8 halfword elements in 'out0' from (psrc)
+ *               Load 8 halfword elements in 'out1' from (psrc + stride)
+ */
+#define LD_H2(RTYPE, psrc, stride, out0, out1) {  \
+  out0 = LD_H(RTYPE, psrc);                       \
+  out1 = LD_H(RTYPE, psrc + stride);              \
+}
+#define LD_UH2(...) LD_H2(v8u16, __VA_ARGS__)
+#define LD_SH2(...) LD_H2(v8i16, __VA_ARGS__)
+
+/* Description : Store 4x4 byte block to destination memory from input vector
+ * Arguments   : Inputs - in0, in1, pdst, stride
+ * Details     : 'Idx0' word element from input vector 'in0' is copied to the
+ *               GP register and stored to (pdst)
+ *               'Idx1' word element from input vector 'in0' is copied to the
+ *               GP register and stored to (pdst + stride)
+ *               'Idx2' word element from input vector 'in0' is copied to the
+ *               GP register and stored to (pdst + 2 * stride)
+ *               'Idx3' word element from input vector 'in0' is copied to the
+ *               GP register and stored to (pdst + 3 * stride)
+ */
+#define ST4x4_UB(in0, in1, idx0, idx1, idx2, idx3, pdst, stride) {  \
+  uint8_t* const pblk_4x4_m = (uint8_t*)pdst;                       \
+  const uint32_t out0_m = __msa_copy_s_w((v4i32)in0, idx0);         \
+  const uint32_t out1_m = __msa_copy_s_w((v4i32)in0, idx1);         \
+  const uint32_t out2_m = __msa_copy_s_w((v4i32)in1, idx2);         \
+  const uint32_t out3_m = __msa_copy_s_w((v4i32)in1, idx3);         \
+  SW4(out0_m, out1_m, out2_m, out3_m, pblk_4x4_m, stride);          \
+}
+
+/* Description : Immediate number of elements to slide
+ * Arguments   : Inputs  - in0, in1, slide_val
+ *               Outputs - out
+ *               Return Type - as per RTYPE
+ * Details     : Byte elements from 'in1' vector are slid into 'in0' by
+ *               value specified in the 'slide_val'
+ */
+#define SLDI_B(RTYPE, in0, in1, slide_val)                      \
+        (RTYPE)__msa_sldi_b((v16i8)in0, (v16i8)in1, slide_val)  \
+
+#define SLDI_UB(...) SLDI_B(v16u8, __VA_ARGS__)
+#define SLDI_SB(...) SLDI_B(v16i8, __VA_ARGS__)
+#define SLDI_SH(...) SLDI_B(v8i16, __VA_ARGS__)
+
+/* Description : Shuffle halfword vector elements as per mask vector
+ * Arguments   : Inputs  - in0, in1, in2, in3, mask0, mask1
+ *               Outputs - out0, out1
+ *               Return Type - as per RTYPE
+ * Details     : halfword elements from 'in0' & 'in1' are copied selectively to
+ *               'out0' as per control vector 'mask0'
+ */
+#define VSHF_H2(RTYPE, in0, in1, in2, in3, mask0, mask1, out0, out1) {  \
+  out0 = (RTYPE)__msa_vshf_h((v8i16)mask0, (v8i16)in1, (v8i16)in0);     \
+  out1 = (RTYPE)__msa_vshf_h((v8i16)mask1, (v8i16)in3, (v8i16)in2);     \
+}
+#define VSHF_H2_UH(...) VSHF_H2(v8u16, __VA_ARGS__)
+#define VSHF_H2_SH(...) VSHF_H2(v8i16, __VA_ARGS__)
+
+/* Description : Clips all signed halfword elements of input vector
+ *               between 0 & 255
+ * Arguments   : Input/output  - val
+ *               Return Type - signed halfword
+ */
+#define CLIP_SH_0_255(val) {                      \
+  const v8i16 max_m = __msa_ldi_h(255);           \
+  val = __msa_maxi_s_h((v8i16)val, 0);            \
+  val = __msa_min_s_h(max_m, (v8i16)val);         \
+}
+#define CLIP_SH2_0_255(in0, in1) {  \
+  CLIP_SH_0_255(in0);               \
+  CLIP_SH_0_255(in1);               \
+}
+
+/* Description : Clips all signed word elements of input vector
+ *               between 0 & 255
+ * Arguments   : Input/output  - val
+ *               Return Type - signed word
+ */
+#define CLIP_SW_0_255(val) {                      \
+  const v4i32 max_m = __msa_ldi_w(255);           \
+  val = __msa_maxi_s_w((v4i32)val, 0);            \
+  val = __msa_min_s_w(max_m, (v4i32)val);         \
+}
+#define CLIP_SW4_0_255(in0, in1, in2, in3) {  \
+  CLIP_SW_0_255(in0);                         \
+  CLIP_SW_0_255(in1);                         \
+  CLIP_SW_0_255(in2);                         \
+  CLIP_SW_0_255(in3);                         \
+}
+
+/* Description : Set element n input vector to GPR value
+ * Arguments   : Inputs - in0, in1, in2, in3
+ *               Output - out
+ *               Return Type - as per RTYPE
+ * Details     : Set element 0 in vector 'out' to value specified in 'in0'
+ */
+#define INSERT_W2(RTYPE, in0, in1, out) {           \
+  out = (RTYPE)__msa_insert_w((v4i32)out, 0, in0);  \
+  out = (RTYPE)__msa_insert_w((v4i32)out, 1, in1);  \
+}
+#define INSERT_W2_UB(...) INSERT_W2(v16u8, __VA_ARGS__)
+#define INSERT_W2_SB(...) INSERT_W2(v16i8, __VA_ARGS__)
+
+#define INSERT_W4(RTYPE, in0, in1, in2, in3, out) {  \
+  out = (RTYPE)__msa_insert_w((v4i32)out, 0, in0);   \
+  out = (RTYPE)__msa_insert_w((v4i32)out, 1, in1);   \
+  out = (RTYPE)__msa_insert_w((v4i32)out, 2, in2);   \
+  out = (RTYPE)__msa_insert_w((v4i32)out, 3, in3);   \
+}
+#define INSERT_W4_UB(...) INSERT_W4(v16u8, __VA_ARGS__)
+#define INSERT_W4_SB(...) INSERT_W4(v16i8, __VA_ARGS__)
+#define INSERT_W4_SW(...) INSERT_W4(v4i32, __VA_ARGS__)
+
+/* Description : Interleave right half of byte elements from vectors
+ * Arguments   : Inputs  - in0, in1, in2, in3
+ *               Outputs - out0, out1
+ *               Return Type - as per RTYPE
+ * Details     : Right half of byte elements of 'in0' and 'in1' are interleaved
+ *               and written to out0.
+ */
+#define ILVR_B2(RTYPE, in0, in1, in2, in3, out0, out1) {  \
+  out0 = (RTYPE)__msa_ilvr_b((v16i8)in0, (v16i8)in1);     \
+  out1 = (RTYPE)__msa_ilvr_b((v16i8)in2, (v16i8)in3);     \
+}
+#define ILVR_B2_UB(...) ILVR_B2(v16u8, __VA_ARGS__)
+#define ILVR_B2_SB(...) ILVR_B2(v16i8, __VA_ARGS__)
+#define ILVR_B2_UH(...) ILVR_B2(v8u16, __VA_ARGS__)
+#define ILVR_B2_SH(...) ILVR_B2(v8i16, __VA_ARGS__)
+#define ILVR_B2_SW(...) ILVR_B2(v4i32, __VA_ARGS__)
+
+#define ILVR_B4(RTYPE, in0, in1, in2, in3, in4, in5, in6, in7,  \
+                out0, out1, out2, out3) {                       \
+  ILVR_B2(RTYPE, in0, in1, in2, in3, out0, out1);               \
+  ILVR_B2(RTYPE, in4, in5, in6, in7, out2, out3);               \
+}
+#define ILVR_B4_UB(...) ILVR_B4(v16u8, __VA_ARGS__)
+#define ILVR_B4_SB(...) ILVR_B4(v16i8, __VA_ARGS__)
+#define ILVR_B4_UH(...) ILVR_B4(v8u16, __VA_ARGS__)
+#define ILVR_B4_SH(...) ILVR_B4(v8i16, __VA_ARGS__)
+#define ILVR_B4_SW(...) ILVR_B4(v4i32, __VA_ARGS__)
+
+/* Description : Interleave right half of halfword elements from vectors
+ * Arguments   : Inputs  - in0, in1, in2, in3
+ *               Outputs - out0, out1
+ *               Return Type - as per RTYPE
+ * Details     : Right half of halfword elements of 'in0' and 'in1' are
+ *               interleaved and written to 'out0'.
+ */
+#define ILVR_H2(RTYPE, in0, in1, in2, in3, out0, out1) {  \
+  out0 = (RTYPE)__msa_ilvr_h((v8i16)in0, (v8i16)in1);     \
+  out1 = (RTYPE)__msa_ilvr_h((v8i16)in2, (v8i16)in3);     \
+}
+#define ILVR_H2_UB(...) ILVR_H2(v16u8, __VA_ARGS__)
+#define ILVR_H2_SH(...) ILVR_H2(v8i16, __VA_ARGS__)
+#define ILVR_H2_SW(...) ILVR_H2(v4i32, __VA_ARGS__)
+
+#define ILVR_H4(RTYPE, in0, in1, in2, in3, in4, in5, in6, in7,  \
+                out0, out1, out2, out3) {                       \
+  ILVR_H2(RTYPE, in0, in1, in2, in3, out0, out1);               \
+  ILVR_H2(RTYPE, in4, in5, in6, in7, out2, out3);               \
+}
+#define ILVR_H4_UB(...) ILVR_H4(v16u8, __VA_ARGS__)
+#define ILVR_H4_SH(...) ILVR_H4(v8i16, __VA_ARGS__)
+#define ILVR_H4_SW(...) ILVR_H4(v4i32, __VA_ARGS__)
+
+/* Description : Interleave right half of double word elements from vectors
+ * Arguments   : Inputs  - in0, in1, in2, in3
+ *               Outputs - out0, out1
+ *               Return Type - as per RTYPE
+ * Details     : Right half of double word elements of 'in0' and 'in1' are
+ *               interleaved and written to 'out0'.
+ */
+#define ILVR_D2(RTYPE, in0, in1, in2, in3, out0, out1) {  \
+  out0 = (RTYPE)__msa_ilvr_d((v2i64)in0, (v2i64)in1);     \
+  out1 = (RTYPE)__msa_ilvr_d((v2i64)in2, (v2i64)in3);     \
+}
+#define ILVR_D2_UB(...) ILVR_D2(v16u8, __VA_ARGS__)
+#define ILVR_D2_SB(...) ILVR_D2(v16i8, __VA_ARGS__)
+#define ILVR_D2_SH(...) ILVR_D2(v8i16, __VA_ARGS__)
+
+#define ILVRL_H2(RTYPE, in0, in1, out0, out1) {        \
+  out0 = (RTYPE)__msa_ilvr_h((v8i16)in0, (v8i16)in1);  \
+  out1 = (RTYPE)__msa_ilvl_h((v8i16)in0, (v8i16)in1);  \
+}
+#define ILVRL_H2_UB(...) ILVRL_H2(v16u8, __VA_ARGS__)
+#define ILVRL_H2_SB(...) ILVRL_H2(v16i8, __VA_ARGS__)
+#define ILVRL_H2_SH(...) ILVRL_H2(v8i16, __VA_ARGS__)
+#define ILVRL_H2_SW(...) ILVRL_H2(v4i32, __VA_ARGS__)
+#define ILVRL_H2_UW(...) ILVRL_H2(v4u32, __VA_ARGS__)
+
+#define ILVRL_W2(RTYPE, in0, in1, out0, out1) {        \
+  out0 = (RTYPE)__msa_ilvr_w((v4i32)in0, (v4i32)in1);  \
+  out1 = (RTYPE)__msa_ilvl_w((v4i32)in0, (v4i32)in1);  \
+}
+#define ILVRL_W2_UB(...) ILVRL_W2(v16u8, __VA_ARGS__)
+#define ILVRL_W2_SH(...) ILVRL_W2(v8i16, __VA_ARGS__)
+#define ILVRL_W2_SW(...) ILVRL_W2(v4i32, __VA_ARGS__)
+
+/* Description : Pack even byte elements of vector pairs
+ *  Arguments   : Inputs  - in0, in1, in2, in3
+ *                Outputs - out0, out1
+ *                Return Type - as per RTYPE
+ *  Details     : Even byte elements of 'in0' are copied to the left half of
+ *                'out0' & even byte elements of 'in1' are copied to the right
+ *                half of 'out0'.
+ */
+#define PCKEV_B2(RTYPE, in0, in1, in2, in3, out0, out1) {  \
+  out0 = (RTYPE)__msa_pckev_b((v16i8)in0, (v16i8)in1);     \
+  out1 = (RTYPE)__msa_pckev_b((v16i8)in2, (v16i8)in3);     \
+}
+#define PCKEV_B2_SB(...) PCKEV_B2(v16i8, __VA_ARGS__)
+#define PCKEV_B2_UB(...) PCKEV_B2(v16u8, __VA_ARGS__)
+#define PCKEV_B2_SH(...) PCKEV_B2(v8i16, __VA_ARGS__)
+#define PCKEV_B2_SW(...) PCKEV_B2(v4i32, __VA_ARGS__)
+
+/* Description : Arithmetic immediate shift right all elements of word vector
+ * Arguments   : Inputs  - in0, in1, shift
+ *               Outputs - in place operation
+ *               Return Type - as per input vector RTYPE
+ * Details     : Each element of vector 'in0' is right shifted by 'shift' and
+ *               the result is written in-place. 'shift' is a GP variable.
+ */
+#define SRAI_W2(RTYPE, in0, in1, shift_val) {  \
+  in0 = (RTYPE)SRAI_W(in0, shift_val);         \
+  in1 = (RTYPE)SRAI_W(in1, shift_val);         \
+}
+#define SRAI_W2_SW(...) SRAI_W2(v4i32, __VA_ARGS__)
+#define SRAI_W2_UW(...) SRAI_W2(v4u32, __VA_ARGS__)
+
+#define SRAI_W4(RTYPE, in0, in1, in2, in3, shift_val) {  \
+  SRAI_W2(RTYPE, in0, in1, shift_val);                   \
+  SRAI_W2(RTYPE, in2, in3, shift_val);                   \
+}
+#define SRAI_W4_SW(...) SRAI_W4(v4i32, __VA_ARGS__)
+#define SRAI_W4_UW(...) SRAI_W4(v4u32, __VA_ARGS__)
+
+/* Description : Arithmetic shift right all elements of half-word vector
+ * Arguments   : Inputs  - in0, in1, shift
+ *               Outputs - in place operation
+ *               Return Type - as per input vector RTYPE
+ * Details     : Each element of vector 'in0' is right shifted by 'shift' and
+ *               the result is written in-place. 'shift' is a GP variable.
+ */
+#define SRAI_H2(RTYPE, in0, in1, shift_val) {  \
+  in0 = (RTYPE)SRAI_H(in0, shift_val);         \
+  in1 = (RTYPE)SRAI_H(in1, shift_val);         \
+}
+#define SRAI_H2_SH(...) SRAI_H2(v8i16, __VA_ARGS__)
+#define SRAI_H2_UH(...) SRAI_H2(v8u16, __VA_ARGS__)
+
+/* Description : Arithmetic rounded shift right all elements of word vector
+ * Arguments   : Inputs  - in0, in1, shift
+ *               Outputs - in place operation
+ *               Return Type - as per input vector RTYPE
+ * Details     : Each element of vector 'in0' is right shifted by 'shift' and
+ *               the result is written in-place. 'shift' is a GP variable.
+ */
+#define SRARI_W2(RTYPE, in0, in1, shift) {        \
+  in0 = (RTYPE)__msa_srari_w((v4i32)in0, shift);  \
+  in1 = (RTYPE)__msa_srari_w((v4i32)in1, shift);  \
+}
+#define SRARI_W2_SW(...) SRARI_W2(v4i32, __VA_ARGS__)
+
+#define SRARI_W4(RTYPE, in0, in1, in2, in3, shift) {  \
+  SRARI_W2(RTYPE, in0, in1, shift);                   \
+  SRARI_W2(RTYPE, in2, in3, shift);                   \
+}
+#define SRARI_W4_SH(...) SRARI_W4(v8i16, __VA_ARGS__)
+#define SRARI_W4_UW(...) SRARI_W4(v4u32, __VA_ARGS__)
+#define SRARI_W4_SW(...) SRARI_W4(v4i32, __VA_ARGS__)
+
+/* Description : Addition of 2 pairs of half-word vectors
+ * Arguments   : Inputs  - in0, in1, in2, in3
+ *               Outputs - out0, out1
+ * Details     : Each element in 'in0' is added to 'in1' and result is written
+ *               to 'out0'.
+ */
+#define ADDVI_H2(RTYPE, in0, in1, in2, in3, out0, out1) {  \
+  out0 = (RTYPE)ADDVI_H(in0, in1);                         \
+  out1 = (RTYPE)ADDVI_H(in2, in3);                         \
+}
+#define ADDVI_H2_SH(...) ADDVI_H2(v8i16, __VA_ARGS__)
+#define ADDVI_H2_UH(...) ADDVI_H2(v8u16, __VA_ARGS__)
+
+/* Description : Addition of 2 pairs of vectors
+ * Arguments   : Inputs  - in0, in1, in2, in3
+ *               Outputs - out0, out1
+ * Details     : Each element in 'in0' is added to 'in1' and result is written
+ *               to 'out0'.
+ */
+#define ADD2(in0, in1, in2, in3, out0, out1) {  \
+  out0 = in0 + in1;                             \
+  out1 = in2 + in3;                             \
+}
+#define ADD4(in0, in1, in2, in3, in4, in5, in6, in7,  \
+             out0, out1, out2, out3) {                \
+  ADD2(in0, in1, in2, in3, out0, out1);               \
+  ADD2(in4, in5, in6, in7, out2, out3);               \
+}
+
+/* Description : Sign extend halfword elements from input vector and return
+ *               the result in pair of vectors
+ * Arguments   : Input   - in            (halfword vector)
+ *               Outputs - out0, out1   (sign extended word vectors)
+ *               Return Type - signed word
+ * Details     : Sign bit of halfword elements from input vector 'in' is
+ *               extracted and interleaved right with same vector 'in0' to
+ *               generate 4 signed word elements in 'out0'
+ *               Then interleaved left with same vector 'in0' to
+ *               generate 4 signed word elements in 'out1'
+ */
+#define UNPCK_SH_SW(in, out0, out1) {                 \
+  const v8i16 tmp_m = __msa_clti_s_h((v8i16)in, 0);   \
+  ILVRL_H2_SW(tmp_m, in, out0, out1);                 \
+}
+
+/* Description : Butterfly of 4 input vectors
+ * Arguments   : Inputs  - in0, in1, in2, in3
+ *               Outputs - out0, out1, out2, out3
+ * Details     : Butterfly operation
+ */
+#define BUTTERFLY_4(in0, in1, in2, in3, out0, out1, out2, out3) {  \
+  out0 = in0 + in3;                                                \
+  out1 = in1 + in2;                                                \
+  out2 = in1 - in2;                                                \
+  out3 = in0 - in3;                                                \
+}
+
+/* Description : Transpose 4x4 block with word elements in vectors
+ * Arguments   : Inputs  - in0, in1, in2, in3
+ *                Outputs - out0, out1, out2, out3
+ *                Return Type - as per RTYPE
+ */
+#define TRANSPOSE4x4_W(RTYPE, in0, in1, in2, in3, out0, out1, out2, out3) {  \
+  v4i32 s0_m, s1_m, s2_m, s3_m;                                              \
+  ILVRL_W2_SW(in1, in0, s0_m, s1_m);                                         \
+  ILVRL_W2_SW(in3, in2, s2_m, s3_m);                                         \
+  out0 = (RTYPE)__msa_ilvr_d((v2i64)s2_m, (v2i64)s0_m);                      \
+  out1 = (RTYPE)__msa_ilvl_d((v2i64)s2_m, (v2i64)s0_m);                      \
+  out2 = (RTYPE)__msa_ilvr_d((v2i64)s3_m, (v2i64)s1_m);                      \
+  out3 = (RTYPE)__msa_ilvl_d((v2i64)s3_m, (v2i64)s1_m);                      \
+}
+#define TRANSPOSE4x4_SW_SW(...) TRANSPOSE4x4_W(v4i32, __VA_ARGS__)
+
+/* Description : Add block 4x4
+ * Arguments   : Inputs - in0, in1, in2, in3, pdst, stride
+ * Details     : Least significant 4 bytes from each input vector are added to
+ *               the destination bytes, clipped between 0-255 and stored.
+ */
+#define ADDBLK_ST4x4_UB(in0, in1, in2, in3, pdst, stride) {     \
+  uint32_t src0_m, src1_m, src2_m, src3_m;                      \
+  v8i16 inp0_m, inp1_m, res0_m, res1_m;                         \
+  v16i8 dst0_m = { 0 };                                         \
+  v16i8 dst1_m = { 0 };                                         \
+  const v16i8 zero_m = { 0 };                                   \
+  ILVR_D2_SH(in1, in0, in3, in2, inp0_m, inp1_m);               \
+  LW4(pdst, stride, src0_m, src1_m, src2_m, src3_m);            \
+  INSERT_W2_SB(src0_m, src1_m, dst0_m);                         \
+  INSERT_W2_SB(src2_m, src3_m, dst1_m);                         \
+  ILVR_B2_SH(zero_m, dst0_m, zero_m, dst1_m, res0_m, res1_m);   \
+  ADD2(res0_m, inp0_m, res1_m, inp1_m, res0_m, res1_m);         \
+  CLIP_SH2_0_255(res0_m, res1_m);                               \
+  PCKEV_B2_SB(res0_m, res0_m, res1_m, res1_m, dst0_m, dst1_m);  \
+  ST4x4_UB(dst0_m, dst1_m, 0, 1, 0, 1, pdst, stride);           \
+}
+
+#endif  /* WEBP_DSP_MSA_MACRO_H_ */

src/dsp/rescaler.c

@@ -173,10 +173,10 @@ void WebPRescalerExportRow(WebPRescaler* const wrk) {
       WebPRescalerExportRowExpand(wrk);
     } else if (wrk->fxy_scale) {
       WebPRescalerExportRowShrink(wrk);
-    } else {  // very special case for src = dst = 1x1
+    } else {  // special case
       int i;
+      assert(wrk->src_height == wrk->dst_height && wrk->x_add == 1);
       assert(wrk->src_width == 1 && wrk->dst_width <= 2);
-      assert(wrk->src_height == 1 && wrk->dst_height == 1);
       for (i = 0; i < wrk->num_channels * wrk->dst_width; ++i) {
         wrk->dst[i] = wrk->irow[i];
         wrk->irow[i] = 0;

src/dsp/rescaler_sse2.c

@@ -18,6 +18,7 @@
 
 #include <assert.h>
 #include "../utils/rescaler.h"
+#include "../utils/utils.h"
 
 //------------------------------------------------------------------------------
 // Implementations of critical functions ImportRow / ExportRow

src/dsp/upsampling_mips_dsp_r2.c

@@ -14,9 +14,7 @@
 
 #include "./dsp.h"
 
-// Code is disabled for now, in favor of the plain-C version
-// TODO(djordje.pesut): adapt the code to reflect the C-version.
-#if 0 // defined(WEBP_USE_MIPS_DSP_R2)
+#if defined(WEBP_USE_MIPS_DSP_R2)
 
 #include <assert.h>
 #include "./yuv.h"
@@ -24,21 +22,21 @@
 #if !defined(WEBP_YUV_USE_TABLE)
 
 #define YUV_TO_RGB(Y, U, V, R, G, B) do {                                      \
-    const int t1 = kYScale * Y;                                                \
-    const int t2 = kVToG * V;                                                  \
-    R = kVToR * V;                                                             \
-    G = kUToG * U;                                                             \
-    B = kUToB * U;                                                             \
+    const int t1 = MultHi(Y, 19077);                                           \
+    const int t2 = MultHi(V, 13320);                                           \
+    R = MultHi(V, 26149);                                                      \
+    G = MultHi(U, 6419);                                                       \
+    B = MultHi(U, 33050);                                                      \
     R = t1 + R;                                                                \
     G = t1 - G;                                                                \
     B = t1 + B;                                                                \
-    R = R + kRCst;                                                             \
-    G = G - t2 + kGCst;                                                        \
-    B = B + kBCst;                                                             \
+    R = R - 14234;                                                             \
+    G = G - t2 + 8708;                                                         \
+    B = B - 17685;                                                             \
     __asm__ volatile (                                                         \
-      "shll_s.w         %[" #R "],      %[" #R "],        9          \n\t"     \
-      "shll_s.w         %[" #G "],      %[" #G "],        9          \n\t"     \
-      "shll_s.w         %[" #B "],      %[" #B "],        9          \n\t"     \
+      "shll_s.w         %[" #R "],      %[" #R "],        17         \n\t"     \
+      "shll_s.w         %[" #G "],      %[" #G "],        17         \n\t"     \
+      "shll_s.w         %[" #B "],      %[" #B "],        17         \n\t"     \
       "precrqu_s.qb.ph  %[" #R "],      %[" #R "],        $zero      \n\t"     \
       "precrqu_s.qb.ph  %[" #G "],      %[" #G "],        $zero      \n\t"     \
       "precrqu_s.qb.ph  %[" #B "],      %[" #B "],        $zero      \n\t"     \
@@ -279,6 +277,6 @@ WEBP_DSP_INIT_STUB(WebPInitYUV444ConvertersMIPSdspR2)
 
 #endif  // WEBP_USE_MIPS_DSP_R2
 
-#if 1  // !(defined(FANCY_UPSAMPLING) && defined(WEBP_USE_MIPS_DSP_R2))
+#if !(defined(FANCY_UPSAMPLING) && defined(WEBP_USE_MIPS_DSP_R2))
 WEBP_DSP_INIT_STUB(WebPInitUpsamplersMIPSdspR2)
 #endif

src/dsp/yuv_mips32.c

@@ -14,8 +14,7 @@
 
 #include "./dsp.h"
 
-// Code is disabled for now, in favor of the plain-C version
-#if 0  // defined(WEBP_USE_MIPS32)
+#if defined(WEBP_USE_MIPS32)
 
 #include "./yuv.h"
 
@@ -29,19 +28,19 @@ static void FUNC_NAME(const uint8_t* y,                                        \
   int i, r, g, b;                                                              \
   int temp0, temp1, temp2, temp3, temp4;                                       \
   for (i = 0; i < (len >> 1); i++) {                                           \
-    temp1 = kVToR * v[0];                                                      \
-    temp3 = kVToG * v[0];                                                      \
-    temp2 = kUToG * u[0];                                                      \
-    temp4 = kUToB * u[0];                                                      \
-    temp0 = kYScale * y[0];                                                    \
-    temp1 += kRCst;                                                            \
-    temp3 -= kGCst;                                                            \
+    temp1 = MultHi(v[0], 26149);                                               \
+    temp3 = MultHi(v[0], 13320);                                               \
+    temp2 = MultHi(u[0], 6419);                                                \
+    temp4 = MultHi(u[0], 33050);                                               \
+    temp0 = MultHi(y[0], 19077);                                               \
+    temp1 -= 14234;                                                            \
+    temp3 -= 8708;                                                             \
     temp2 += temp3;                                                            \
-    temp4 += kBCst;                                                            \
+    temp4 -= 17685;                                                            \
     r = VP8Clip8(temp0 + temp1);                                               \
     g = VP8Clip8(temp0 - temp2);                                               \
     b = VP8Clip8(temp0 + temp4);                                               \
-    temp0 = kYScale * y[1];                                                    \
+    temp0 = MultHi(y[1], 19077);                                               \
     dst[R] = r;                                                                \
     dst[G] = g;                                                                \
     dst[B] = b;                                                                \
@@ -59,15 +58,15 @@ static void FUNC_NAME(const uint8_t* y,                                        \
     dst += 2 * XSTEP;                                                          \
   }                                                                            \
   if (len & 1) {                                                               \
-    temp1 = kVToR * v[0];                                                      \
-    temp3 = kVToG * v[0];                                                      \
-    temp2 = kUToG * u[0];                                                      \
-    temp4 = kUToB * u[0];                                                      \
-    temp0 = kYScale * y[0];                                                    \
-    temp1 += kRCst;                                                            \
-    temp3 -= kGCst;                                                            \
+    temp1 = MultHi(v[0], 26149);                                               \
+    temp3 = MultHi(v[0], 13320);                                               \
+    temp2 = MultHi(u[0], 6419);                                                \
+    temp4 = MultHi(u[0], 33050);                                               \
+    temp0 = MultHi(y[0], 19077);                                               \
+    temp1 -= 14234;                                                            \
+    temp3 -= 8708;                                                             \
     temp2 += temp3;                                                            \
-    temp4 += kBCst;                                                            \
+    temp4 -= 17685;                                                            \
     r = VP8Clip8(temp0 + temp1);                                               \
     g = VP8Clip8(temp0 - temp2);                                               \
     b = VP8Clip8(temp0 + temp4);                                               \

src/dsp/yuv_mips_dsp_r2.c

@@ -14,8 +14,7 @@
 
 #include "./dsp.h"
 
-// Code is disabled for now, in favor of the plain-C version
-#if 0  // defined(WEBP_USE_MIPS_DSP_R2)
+#if defined(WEBP_USE_MIPS_DSP_R2)
 
 #include "./yuv.h"
 
@@ -31,10 +30,10 @@
   "mul              %[temp2],   %[t_con_3],     %[temp4]        \n\t"          \
   "mul              %[temp4],   %[t_con_4],     %[temp4]        \n\t"          \
   "mul              %[temp0],   %[t_con_5],     %[temp0]        \n\t"          \
-  "addu             %[temp1],   %[temp1],       %[t_con_6]      \n\t"          \
+  "subu             %[temp1],   %[temp1],       %[t_con_6]      \n\t"          \
   "subu             %[temp3],   %[temp3],       %[t_con_7]      \n\t"          \
   "addu             %[temp2],   %[temp2],       %[temp3]        \n\t"          \
-  "addu             %[temp4],   %[temp4],       %[t_con_8]      \n\t"          \
+  "subu             %[temp4],   %[temp4],       %[t_con_8]      \n\t"          \
 
 #define ROW_FUNC_PART_2(R, G, B, K)                                            \
   "addu             %[temp5],   %[temp0],       %[temp1]        \n\t"          \
@@ -43,12 +42,12 @@
 ".if " #K "                                                     \n\t"          \
   "lbu              %[temp0],   1(%[y])                         \n\t"          \
 ".endif                                                         \n\t"          \
-  "shll_s.w         %[temp5],   %[temp5],       9               \n\t"          \
-  "shll_s.w         %[temp6],   %[temp6],       9               \n\t"          \
+  "shll_s.w         %[temp5],   %[temp5],       17              \n\t"          \
+  "shll_s.w         %[temp6],   %[temp6],       17              \n\t"          \
 ".if " #K "                                                     \n\t"          \
   "mul              %[temp0],   %[t_con_5],     %[temp0]        \n\t"          \
 ".endif                                                         \n\t"          \
-  "shll_s.w         %[temp7],   %[temp7],       9               \n\t"          \
+  "shll_s.w         %[temp7],   %[temp7],       17              \n\t"          \
   "precrqu_s.qb.ph  %[temp5],   %[temp5],       $zero           \n\t"          \
   "precrqu_s.qb.ph  %[temp6],   %[temp6],       $zero           \n\t"          \
   "precrqu_s.qb.ph  %[temp7],   %[temp7],       $zero           \n\t"          \
@@ -75,14 +74,14 @@ static void FUNC_NAME(const uint8_t* y,                                        \
                       uint8_t* dst, int len) {                                 \
   int i;                                                                       \
   uint32_t temp0, temp1, temp2, temp3, temp4, temp5, temp6, temp7;             \
-  const int t_con_1 = kVToR;                                                   \
-  const int t_con_2 = kVToG;                                                   \
-  const int t_con_3 = kUToG;                                                   \
-  const int t_con_4 = kUToB;                                                   \
-  const int t_con_5 = kYScale;                                                 \
-  const int t_con_6 = kRCst;                                                   \
-  const int t_con_7 = kGCst;                                                   \
-  const int t_con_8 = kBCst;                                                   \
+  const int t_con_1 = 26149;                                                   \
+  const int t_con_2 = 13320;                                                   \
+  const int t_con_3 = 6419;                                                    \
+  const int t_con_4 = 33050;                                                   \
+  const int t_con_5 = 19077;                                                   \
+  const int t_con_6 = 14234;                                                   \
+  const int t_con_7 = 8708;                                                    \
+  const int t_con_8 = 17685;                                                   \
   for (i = 0; i < (len >> 1); i++) {                                           \
     __asm__ volatile (                                                         \
       ROW_FUNC_PART_1()                                                        \

src/dsp/yuv_sse2.c

@@ -33,7 +33,8 @@ static void ConvertYUV444ToRGB(const __m128i* const Y0,
   const __m128i k19077 = _mm_set1_epi16(19077);
   const __m128i k26149 = _mm_set1_epi16(26149);
   const __m128i k14234 = _mm_set1_epi16(14234);
-  const __m128i k33050 = _mm_set1_epi16(33050);
+  // 33050 doesn't fit in a signed short: only use this with unsigned arithmetic
+  const __m128i k33050 = _mm_set1_epi16((short)33050);
   const __m128i k17685 = _mm_set1_epi16(17685);
   const __m128i k6419  = _mm_set1_epi16(6419);
   const __m128i k13320 = _mm_set1_epi16(13320);

src/enc/alpha.c

@@ -79,7 +79,11 @@ static int EncodeLossless(const uint8_t* const data, int width, int height,
   config.quality = 8.f * effort_level;
   assert(config.quality >= 0 && config.quality <= 100.f);
 
-  ok = (VP8LEncodeStream(&config, &picture, bw) == VP8_ENC_OK);
+  // TODO(urvang): Temporary fix to avoid generating images that trigger
+  // a decoder bug related to alpha with color cache.
+  // See: https://code.google.com/p/webp/issues/detail?id=239
+  // Need to re-enable this later.
+  ok = (VP8LEncodeStream(&config, &picture, bw, 0 /*use_cache*/) == VP8_ENC_OK);
   WebPPictureFree(&picture);
   ok = ok && !bw->error_;
   if (!ok) {
@@ -118,7 +122,6 @@ static int EncodeAlphaInternal(const uint8_t* const data, int width, int height,
   assert(method >= ALPHA_NO_COMPRESSION);
   assert(method <= ALPHA_LOSSLESS_COMPRESSION);
   assert(sizeof(header) == ALPHA_HEADER_LEN);
-  // TODO(skal): have a common function and #define's to validate alpha params.
 
   filter_func = WebPFilters[filter];
   if (filter_func != NULL) {

src/enc/analysis.c

@@ -307,6 +307,7 @@ static int MBAnalyzeBestIntra4Mode(VP8EncIterator* const it,
 
 static int MBAnalyzeBestUVMode(VP8EncIterator* const it) {
   int best_alpha = DEFAULT_ALPHA;
+  int smallest_alpha = 0;
   int best_mode = 0;
   const int max_mode = MAX_UV_MODE;
   int mode;
@@ -322,6 +323,10 @@ static int MBAnalyzeBestUVMode(VP8EncIterator* const it) {
     alpha = GetAlpha(&histo);
     if (IS_BETTER_ALPHA(alpha, best_alpha)) {
       best_alpha = alpha;
+    }
+    // The best prediction mode tends to be the one with the smallest alpha.
+    if (mode == 0 || alpha < smallest_alpha) {
+      smallest_alpha = alpha;
       best_mode = mode;
     }
   }

src/enc/backward_references.h

@@ -115,11 +115,12 @@ static WEBP_INLINE uint32_t PixOrCopyDistance(const PixOrCopy* const p) {
 
 typedef struct VP8LHashChain VP8LHashChain;
 struct VP8LHashChain {
-  // Stores the most recently added position with the given hash value.
-  int32_t hash_to_first_index_[HASH_SIZE];
-  // chain_[pos] stores the previous position with the same hash value
-  // for every pixel in the image.
-  int32_t* chain_;
+  // The 20 most significant bits contain the offset at which the best match
+  // is found. These 20 bits are the limit defined by GetWindowSizeForHashChain
+  // (through WINDOW_SIZE = 1<<20).
+  // The lower 12 bits contain the length of the match. The 12 bit limit is
+  // defined in MaxFindCopyLength with MAX_LENGTH=4096.
+  uint32_t* offset_length_;
   // This is the maximum size of the hash_chain that can be constructed.
   // Typically this is the pixel count (width x height) for a given image.
   int size_;
@@ -127,6 +128,9 @@ struct VP8LHashChain {
 
 // Must be called first, to set size.
 int VP8LHashChainInit(VP8LHashChain* const p, int size);
+// Pre-compute the best matches for argb.
+int VP8LHashChainFill(VP8LHashChain* const p, int quality,
+                      const uint32_t* const argb, int xsize, int ysize);
 void VP8LHashChainClear(VP8LHashChain* const p);  // release memory
 
 // -----------------------------------------------------------------------------
@@ -192,8 +196,8 @@ static WEBP_INLINE void VP8LRefsCursorNext(VP8LRefsCursor* const c) {
 // refs[0] or refs[1].
 VP8LBackwardRefs* VP8LGetBackwardReferences(
     int width, int height, const uint32_t* const argb, int quality,
-    int low_effort, int* const cache_bits, VP8LHashChain* const hash_chain,
-    VP8LBackwardRefs refs[2]);
+    int low_effort, int* const cache_bits,
+    const VP8LHashChain* const hash_chain, VP8LBackwardRefs refs[2]);
 
 #ifdef __cplusplus
 }

src/enc/cost.c

@@ -281,18 +281,6 @@ int VP8GetCostUV(VP8EncIterator* const it, const VP8ModeScore* const rd) {
 //------------------------------------------------------------------------------
 // Recording of token probabilities.
 
-// Record proba context used
-static int Record(int bit, proba_t* const stats) {
-  proba_t p = *stats;
-  if (p >= 0xffff0000u) {               // an overflow is inbound.
-    p = ((p + 1u) >> 1) & 0x7fff7fffu;  // -> divide the stats by 2.
-  }
-  // record bit count (lower 16 bits) and increment total count (upper 16 bits).
-  p += 0x00010000u + bit;
-  *stats = p;
-  return bit;
-}
-
 // We keep the table-free variant around for reference, in case.
 #define USE_LEVEL_CODE_TABLE
 
@@ -303,31 +291,31 @@ int VP8RecordCoeffs(int ctx, const VP8Residual* const res) {
   // should be stats[VP8EncBands[n]], but it's equivalent for n=0 or 1
   proba_t* s = res->stats[n][ctx];
   if (res->last  < 0) {
-    Record(0, s + 0);
+    VP8RecordStats(0, s + 0);
     return 0;
   }
   while (n <= res->last) {
     int v;
-    Record(1, s + 0);  // order of record doesn't matter
+    VP8RecordStats(1, s + 0);  // order of record doesn't matter
     while ((v = res->coeffs[n++]) == 0) {
-      Record(0, s + 1);
+      VP8RecordStats(0, s + 1);
       s = res->stats[VP8EncBands[n]][0];
     }
-    Record(1, s + 1);
-    if (!Record(2u < (unsigned int)(v + 1), s + 2)) {  // v = -1 or 1
+    VP8RecordStats(1, s + 1);
+    if (!VP8RecordStats(2u < (unsigned int)(v + 1), s + 2)) {  // v = -1 or 1
       s = res->stats[VP8EncBands[n]][1];
     } else {
       v = abs(v);
 #if !defined(USE_LEVEL_CODE_TABLE)
-      if (!Record(v > 4, s + 3)) {
-        if (Record(v != 2, s + 4))
-          Record(v == 4, s + 5);
-      } else if (!Record(v > 10, s + 6)) {
-        Record(v > 6, s + 7);
-      } else if (!Record((v >= 3 + (8 << 2)), s + 8)) {
-        Record((v >= 3 + (8 << 1)), s + 9);
+      if (!VP8RecordStats(v > 4, s + 3)) {
+        if (VP8RecordStats(v != 2, s + 4))
+          VP8RecordStats(v == 4, s + 5);
+      } else if (!VP8RecordStats(v > 10, s + 6)) {
+        VP8RecordStats(v > 6, s + 7);
+      } else if (!VP8RecordStats((v >= 3 + (8 << 2)), s + 8)) {
+        VP8RecordStats((v >= 3 + (8 << 1)), s + 9);
       } else {
-        Record((v >= 3 + (8 << 3)), s + 10);
+        VP8RecordStats((v >= 3 + (8 << 3)), s + 10);
       }
 #else
       if (v > MAX_VARIABLE_LEVEL) {
@@ -340,14 +328,14 @@ int VP8RecordCoeffs(int ctx, const VP8Residual* const res) {
         int i;
         for (i = 0; (pattern >>= 1) != 0; ++i) {
           const int mask = 2 << i;
-          if (pattern & 1) Record(!!(bits & mask), s + 3 + i);
+          if (pattern & 1) VP8RecordStats(!!(bits & mask), s + 3 + i);
         }
       }
 #endif
       s = res->stats[VP8EncBands[n]][2];
     }
   }
-  if (n < 16) Record(0, s + 0);
+  if (n < 16) VP8RecordStats(0, s + 0);
   return 1;
 }
 

src/enc/cost.h

@@ -41,6 +41,20 @@ void VP8InitResidual(int first, int coeff_type,
 
 int VP8RecordCoeffs(int ctx, const VP8Residual* const res);
 
+// Record proba context used.
+static WEBP_INLINE int VP8RecordStats(int bit, proba_t* const stats) {
+  proba_t p = *stats;
+  // An overflow is inbound. Note we handle this at 0xfffe0000u instead of
+  // 0xffff0000u to make sure p + 1u does not overflow.
+  if (p >= 0xfffe0000u) {
+    p = ((p + 1u) >> 1) & 0x7fff7fffu;  // -> divide the stats by 2.
+  }
+  // record bit count (lower 16 bits) and increment total count (upper 16 bits).
+  p += 0x00010000u + bit;
+  *stats = p;
+  return bit;
+}
+
 // Cost of coding one event with probability 'proba'.
 static WEBP_INLINE int VP8BitCost(int bit, uint8_t proba) {
   return !bit ? VP8EntropyCost[proba] : VP8EntropyCost[255 - proba];

src/enc/filter.c

@@ -107,10 +107,9 @@ static void DoFilter(const VP8EncIterator* const it, int level) {
 //------------------------------------------------------------------------------
 // SSIM metric
 
-enum { KERNEL = 3 };
 static const double kMinValue = 1.e-10;  // minimal threshold
 
-void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst) {
+void VP8SSIMAddStats(const VP8DistoStats* const src, VP8DistoStats* const dst) {
   dst->w   += src->w;
   dst->xm  += src->xm;
   dst->ym  += src->ym;
@@ -119,32 +118,7 @@ void VP8SSIMAddStats(const DistoStats* const src, DistoStats* const dst) {
   dst->yym += src->yym;
 }
 
-static void VP8SSIMAccumulate(const uint8_t* src1, int stride1,
-                              const uint8_t* src2, int stride2,
-                              int xo, int yo, int W, int H,
-                              DistoStats* const stats) {
-  const int ymin = (yo - KERNEL < 0) ? 0 : yo - KERNEL;
-  const int ymax = (yo + KERNEL > H - 1) ? H - 1 : yo + KERNEL;
-  const int xmin = (xo - KERNEL < 0) ? 0 : xo - KERNEL;
-  const int xmax = (xo + KERNEL > W - 1) ? W - 1 : xo + KERNEL;
-  int x, y;
-  src1 += ymin * stride1;
-  src2 += ymin * stride2;
-  for (y = ymin; y <= ymax; ++y, src1 += stride1, src2 += stride2) {
-    for (x = xmin; x <= xmax; ++x) {
-      const int s1 = src1[x];
-      const int s2 = src2[x];
-      stats->w   += 1;
-      stats->xm  += s1;
-      stats->ym  += s2;
-      stats->xxm += s1 * s1;
-      stats->xym += s1 * s2;
-      stats->yym += s2 * s2;
-    }
-  }
-}
-
-double VP8SSIMGet(const DistoStats* const stats) {
+double VP8SSIMGet(const VP8DistoStats* const stats) {
   const double xmxm = stats->xm * stats->xm;
   const double ymym = stats->ym * stats->ym;
   const double xmym = stats->xm * stats->ym;
@@ -165,7 +139,7 @@ double VP8SSIMGet(const DistoStats* const stats) {
   return (fden != 0.) ? fnum / fden : kMinValue;
 }
 
-double VP8SSIMGetSquaredError(const DistoStats* const s) {
+double VP8SSIMGetSquaredError(const VP8DistoStats* const s) {
   if (s->w > 0.) {
     const double iw2 = 1. / (s->w * s->w);
     const double sxx = s->xxm * s->w - s->xm * s->xm;
@@ -177,34 +151,66 @@ double VP8SSIMGetSquaredError(const DistoStats* const s) {
   return kMinValue;
 }
 
-void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
-                            const uint8_t* src2, int stride2,
-                            int W, int H, DistoStats* const stats) {
-  int x, y;
-  for (y = 0; y < H; ++y) {
-    for (x = 0; x < W; ++x) {
-      VP8SSIMAccumulate(src1, stride1, src2, stride2, x, y, W, H, stats);
-    }
+#define LIMIT(A, M)  ((A) > (M) ? (M) : (A))
+static void VP8SSIMAccumulateRow(const uint8_t* src1, int stride1,
+                                 const uint8_t* src2, int stride2,
+                                 int y, int W, int H,
+                                 VP8DistoStats* const stats) {
+  int x = 0;
+  const int w0 = LIMIT(VP8_SSIM_KERNEL, W);
+  for (x = 0; x < w0; ++x) {
+    VP8SSIMAccumulateClipped(src1, stride1, src2, stride2, x, y, W, H, stats);
+  }
+  for (; x <= W - 8 + VP8_SSIM_KERNEL; ++x) {
+    VP8SSIMAccumulate(
+        src1 + (y - VP8_SSIM_KERNEL) * stride1 + (x - VP8_SSIM_KERNEL), stride1,
+        src2 + (y - VP8_SSIM_KERNEL) * stride2 + (x - VP8_SSIM_KERNEL), stride2,
+        stats);
+  }
+  for (; x < W; ++x) {
+    VP8SSIMAccumulateClipped(src1, stride1, src2, stride2, x, y, W, H, stats);
   }
 }
 
+void VP8SSIMAccumulatePlane(const uint8_t* src1, int stride1,
+                            const uint8_t* src2, int stride2,
+                            int W, int H, VP8DistoStats* const stats) {
+  int x, y;
+  const int h0 = LIMIT(VP8_SSIM_KERNEL, H);
+  const int h1 = LIMIT(VP8_SSIM_KERNEL, H - VP8_SSIM_KERNEL);
+  for (y = 0; y < h0; ++y) {
+    for (x = 0; x < W; ++x) {
+      VP8SSIMAccumulateClipped(src1, stride1, src2, stride2, x, y, W, H, stats);
+    }
+  }
+  for (; y < h1; ++y) {
+    VP8SSIMAccumulateRow(src1, stride1, src2, stride2, y, W, H, stats);
+  }
+  for (; y < H; ++y) {
+    for (x = 0; x < W; ++x) {
+      VP8SSIMAccumulateClipped(src1, stride1, src2, stride2, x, y, W, H, stats);
+    }
+  }
+}
+#undef LIMIT
+
 static double GetMBSSIM(const uint8_t* yuv1, const uint8_t* yuv2) {
   int x, y;
-  DistoStats s = { .0, .0, .0, .0, .0, .0 };
+  VP8DistoStats s = { .0, .0, .0, .0, .0, .0 };
 
   // compute SSIM in a 10 x 10 window
-  for (x = 3; x < 13; x++) {
-    for (y = 3; y < 13; y++) {
-      VP8SSIMAccumulate(yuv1 + Y_OFF_ENC, BPS, yuv2 + Y_OFF_ENC, BPS,
-                        x, y, 16, 16, &s);
+  for (y = VP8_SSIM_KERNEL; y < 16 - VP8_SSIM_KERNEL; y++) {
+    for (x = VP8_SSIM_KERNEL; x < 16 - VP8_SSIM_KERNEL; x++) {
+      VP8SSIMAccumulateClipped(yuv1 + Y_OFF_ENC, BPS, yuv2 + Y_OFF_ENC, BPS,
+                               x, y, 16, 16, &s);
     }
   }
   for (x = 1; x < 7; x++) {
     for (y = 1; y < 7; y++) {
-      VP8SSIMAccumulate(yuv1 + U_OFF_ENC, BPS, yuv2 + U_OFF_ENC, BPS,
-                        x, y, 8, 8, &s);
-      VP8SSIMAccumulate(yuv1 + V_OFF_ENC, BPS, yuv2 + V_OFF_ENC, BPS,
-                        x, y, 8, 8, &s);
+      VP8SSIMAccumulateClipped(yuv1 + U_OFF_ENC, BPS, yuv2 + U_OFF_ENC, BPS,
+                               x, y, 8, 8, &s);
+      VP8SSIMAccumulateClipped(yuv1 + V_OFF_ENC, BPS, yuv2 + V_OFF_ENC, BPS,
+                               x, y, 8, 8, &s);
     }
   }
   return VP8SSIMGet(&s);
@@ -222,6 +228,7 @@ void VP8InitFilter(VP8EncIterator* const it) {
         (*it->lf_stats_)[s][i] = 0;
       }
     }
+    VP8SSIMDspInit();
   }
 }
 

src/enc/frame.c

@@ -185,6 +185,13 @@ static int GetProba(int a, int b) {
                       : (255 * a + total / 2) / total;  // rounded proba
 }
 
+static void ResetSegments(VP8Encoder* const enc) {
+  int n;
+  for (n = 0; n < enc->mb_w_ * enc->mb_h_; ++n) {
+    enc->mb_info_[n].segment_ = 0;
+  }
+}
+
 static void SetSegmentProbas(VP8Encoder* const enc) {
   int p[NUM_MB_SEGMENTS] = { 0 };
   int n;
@@ -206,6 +213,7 @@ static void SetSegmentProbas(VP8Encoder* const enc) {
 
     enc->segment_hdr_.update_map_ =
         (probas[0] != 255) || (probas[1] != 255) || (probas[2] != 255);
+    if (!enc->segment_hdr_.update_map_) ResetSegments(enc);
     enc->segment_hdr_.size_ =
         p[0] * (VP8BitCost(0, probas[0]) + VP8BitCost(0, probas[1])) +
         p[1] * (VP8BitCost(0, probas[0]) + VP8BitCost(1, probas[1])) +
@@ -406,9 +414,7 @@ static int RecordTokens(VP8EncIterator* const it, const VP8ModeScore* const rd,
     VP8InitResidual(0, 1, enc, &res);
     VP8SetResidualCoeffs(rd->y_dc_levels, &res);
     it->top_nz_[8] = it->left_nz_[8] =
-        VP8RecordCoeffTokens(ctx, 1,
-                             res.first, res.last, res.coeffs, tokens);
-    VP8RecordCoeffs(ctx, &res);
+        VP8RecordCoeffTokens(ctx, &res, tokens);
     VP8InitResidual(1, 0, enc, &res);
   } else {
     VP8InitResidual(0, 3, enc, &res);
@@ -420,9 +426,7 @@ static int RecordTokens(VP8EncIterator* const it, const VP8ModeScore* const rd,
       const int ctx = it->top_nz_[x] + it->left_nz_[y];
       VP8SetResidualCoeffs(rd->y_ac_levels[x + y * 4], &res);
       it->top_nz_[x] = it->left_nz_[y] =
-          VP8RecordCoeffTokens(ctx, res.coeff_type,
-                               res.first, res.last, res.coeffs, tokens);
-      VP8RecordCoeffs(ctx, &res);
+          VP8RecordCoeffTokens(ctx, &res, tokens);
     }
   }
 
@@ -434,9 +438,7 @@ static int RecordTokens(VP8EncIterator* const it, const VP8ModeScore* const rd,
         const int ctx = it->top_nz_[4 + ch + x] + it->left_nz_[4 + ch + y];
         VP8SetResidualCoeffs(rd->uv_levels[ch * 2 + x + y * 2], &res);
         it->top_nz_[4 + ch + x] = it->left_nz_[4 + ch + y] =
-            VP8RecordCoeffTokens(ctx, 2,
-                                 res.first, res.last, res.coeffs, tokens);
-        VP8RecordCoeffs(ctx, &res);
+            VP8RecordCoeffTokens(ctx, &res, tokens);
       }
     }
   }
@@ -814,7 +816,7 @@ int VP8EncTokenLoop(VP8Encoder* const enc) {
            num_pass_left, stats.last_value, stats.value,
            stats.last_q, stats.q, stats.dq);
 #endif
-    if (size_p0 > PARTITION0_SIZE_LIMIT) {
+    if (enc->max_i4_header_bits_ > 0 && size_p0 > PARTITION0_SIZE_LIMIT) {
       ++num_pass_left;
       enc->max_i4_header_bits_ >>= 1;  // strengthen header bit limitation...
       continue;                        // ...and start over

src/enc/histogram.c

@@ -386,29 +386,27 @@ static void UpdateHistogramCost(VP8LHistogram* const h) {
 }
 
 static int GetBinIdForEntropy(double min, double max, double val) {
-  const double range = max - min + 1e-6;
-  const double delta = val - min;
-  return (int)(NUM_PARTITIONS * delta / range);
+  const double range = max - min;
+  if (range > 0.) {
+    const double delta = val - min;
+    return (int)((NUM_PARTITIONS - 1e-6) * delta / range);
+  } else {
+    return 0;
+  }
 }
 
-static int GetHistoBinIndexLowEffort(
-    const VP8LHistogram* const h, const DominantCostRange* const c) {
-  const int bin_id = GetBinIdForEntropy(c->literal_min_, c->literal_max_,
-                                        h->literal_cost_);
+static int GetHistoBinIndex(const VP8LHistogram* const h,
+                            const DominantCostRange* const c, int low_effort) {
+  int bin_id = GetBinIdForEntropy(c->literal_min_, c->literal_max_,
+                                  h->literal_cost_);
   assert(bin_id < NUM_PARTITIONS);
-  return bin_id;
-}
-
-static int GetHistoBinIndex(
-    const VP8LHistogram* const h, const DominantCostRange* const c) {
-  const int bin_id =
-      GetBinIdForEntropy(c->blue_min_, c->blue_max_, h->blue_cost_) +
-      NUM_PARTITIONS * GetBinIdForEntropy(c->red_min_, c->red_max_,
-                                          h->red_cost_) +
-      NUM_PARTITIONS * NUM_PARTITIONS * GetBinIdForEntropy(c->literal_min_,
-                                                           c->literal_max_,
-                                                           h->literal_cost_);
-  assert(bin_id < BIN_SIZE);
+  if (!low_effort) {
+    bin_id = bin_id * NUM_PARTITIONS
+           + GetBinIdForEntropy(c->red_min_, c->red_max_, h->red_cost_);
+    bin_id = bin_id * NUM_PARTITIONS
+           + GetBinIdForEntropy(c->blue_min_, c->blue_max_, h->blue_cost_);
+    assert(bin_id < BIN_SIZE);
+  }
   return bin_id;
 }
 
@@ -469,16 +467,13 @@ static void HistogramAnalyzeEntropyBin(VP8LHistogramSet* const image_histo,
   // bin-hash histograms on three of the dominant (literal, red and blue)
   // symbol costs.
   for (i = 0; i < histo_size; ++i) {
-    int num_histos;
-    VP8LHistogram* const histo = histograms[i];
-    const int16_t bin_id = low_effort ?
-        (int16_t)GetHistoBinIndexLowEffort(histo, &cost_range) :
-        (int16_t)GetHistoBinIndex(histo, &cost_range);
+    const VP8LHistogram* const histo = histograms[i];
+    const int bin_id = GetHistoBinIndex(histo, &cost_range, low_effort);
     const int bin_offset = bin_id * bin_depth;
     // bin_map[n][0] for every bin 'n' maintains the counter for the number of
     // histograms in that bin.
     // Get and increment the num_histos in that bin.
-    num_histos = ++bin_map[bin_offset];
+    const int num_histos = ++bin_map[bin_offset];
     assert(bin_offset + num_histos < bin_depth * BIN_SIZE);
     // Add histogram i'th index at num_histos (last) position in the bin_map.
     bin_map[bin_offset + num_histos] = i;
@@ -597,8 +592,8 @@ static int HistoQueueInit(HistoQueue* const histo_queue, const int max_index) {
   histo_queue->max_size = max_index * max_index;
   // We allocate max_size + 1 because the last element at index "size" is
   // used as temporary data (and it could be up to max_size).
-  histo_queue->queue = WebPSafeMalloc(histo_queue->max_size + 1,
-                                      sizeof(*histo_queue->queue));
+  histo_queue->queue = (HistogramPair*)WebPSafeMalloc(
+      histo_queue->max_size + 1, sizeof(*histo_queue->queue));
   return histo_queue->queue != NULL;
 }
 
@@ -636,8 +631,11 @@ static void UpdateQueueFront(HistoQueue* const histo_queue) {
 // -----------------------------------------------------------------------------
 
 static void PreparePair(VP8LHistogram** histograms, int idx1, int idx2,
-                        HistogramPair* const pair,
-                        VP8LHistogram* const histos) {
+                        HistogramPair* const pair) {
+  VP8LHistogram* h1;
+  VP8LHistogram* h2;
+  double sum_cost;
+
   if (idx1 > idx2) {
     const int tmp = idx2;
     idx2 = idx1;
@@ -645,21 +643,24 @@ static void PreparePair(VP8LHistogram** histograms, int idx1, int idx2,
   }
   pair->idx1 = idx1;
   pair->idx2 = idx2;
-  pair->cost_diff =
-      HistogramAddEval(histograms[idx1], histograms[idx2], histos, 0);
-  pair->cost_combo = histos->bit_cost_;
+  h1 = histograms[idx1];
+  h2 = histograms[idx2];
+  sum_cost = h1->bit_cost_ + h2->bit_cost_;
+  pair->cost_combo = 0.;
+  GetCombinedHistogramEntropy(h1, h2, sum_cost, &pair->cost_combo);
+  pair->cost_diff = pair->cost_combo - sum_cost;
 }
 
 // Combines histograms by continuously choosing the one with the highest cost
 // reduction.
-static int HistogramCombineGreedy(VP8LHistogramSet* const image_histo,
-                                  VP8LHistogram* const histos) {
+static int HistogramCombineGreedy(VP8LHistogramSet* const image_histo) {
   int ok = 0;
   int image_histo_size = image_histo->size;
   int i, j;
   VP8LHistogram** const histograms = image_histo->histograms;
   // Indexes of remaining histograms.
-  int* const clusters = WebPSafeMalloc(image_histo_size, sizeof(*clusters));
+  int* const clusters =
+      (int*)WebPSafeMalloc(image_histo_size, sizeof(*clusters));
   // Priority queue of histogram pairs.
   HistoQueue histo_queue;
 
@@ -672,8 +673,7 @@ static int HistogramCombineGreedy(VP8LHistogramSet* const image_histo,
     clusters[i] = i;
     for (j = i + 1; j < image_histo_size; ++j) {
       // Initialize positions array.
-      PreparePair(histograms, i, j, &histo_queue.queue[histo_queue.size],
-                  histos);
+      PreparePair(histograms, i, j, &histo_queue.queue[histo_queue.size]);
       UpdateQueueFront(&histo_queue);
     }
   }
@@ -715,7 +715,7 @@ static int HistogramCombineGreedy(VP8LHistogramSet* const image_histo,
     for (i = 0; i < image_histo_size; ++i) {
       if (clusters[i] != idx1) {
         PreparePair(histograms, idx1, clusters[i],
-                    &histo_queue.queue[histo_queue.size], histos);
+                    &histo_queue.queue[histo_queue.size]);
         UpdateQueueFront(&histo_queue);
       }
     }
@@ -736,11 +736,10 @@ static int HistogramCombineGreedy(VP8LHistogramSet* const image_histo,
   return ok;
 }
 
-static VP8LHistogram* HistogramCombineStochastic(
-    VP8LHistogramSet* const image_histo,
-    VP8LHistogram* tmp_histo,
-    VP8LHistogram* best_combo,
-    int quality, int min_cluster_size) {
+static void HistogramCombineStochastic(VP8LHistogramSet* const image_histo,
+                                       VP8LHistogram* tmp_histo,
+                                       VP8LHistogram* best_combo,
+                                       int quality, int min_cluster_size) {
   int iter;
   uint32_t seed = 0;
   int tries_with_no_success = 0;
@@ -800,7 +799,6 @@ static VP8LHistogram* HistogramCombineStochastic(
     }
   }
   image_histo->size = image_histo_size;
-  return best_combo;
 }
 
 // -----------------------------------------------------------------------------
@@ -808,24 +806,23 @@ static VP8LHistogram* HistogramCombineStochastic(
 
 // Find the best 'out' histogram for each of the 'in' histograms.
 // Note: we assume that out[]->bit_cost_ is already up-to-date.
-static void HistogramRemap(const VP8LHistogramSet* const orig_histo,
-                           const VP8LHistogramSet* const image_histo,
+static void HistogramRemap(const VP8LHistogramSet* const in,
+                           const VP8LHistogramSet* const out,
                            uint16_t* const symbols) {
   int i;
-  VP8LHistogram** const orig_histograms = orig_histo->histograms;
-  VP8LHistogram** const histograms = image_histo->histograms;
-  const int orig_histo_size = orig_histo->size;
-  const int image_histo_size = image_histo->size;
-  if (image_histo_size > 1) {
-    for (i = 0; i < orig_histo_size; ++i) {
+  VP8LHistogram** const in_histo = in->histograms;
+  VP8LHistogram** const out_histo = out->histograms;
+  const int in_size = in->size;
+  const int out_size = out->size;
+  if (out_size > 1) {
+    for (i = 0; i < in_size; ++i) {
       int best_out = 0;
-      double best_bits =
-          HistogramAddThresh(histograms[0], orig_histograms[i], MAX_COST);
+      double best_bits = MAX_COST;
       int k;
-      for (k = 1; k < image_histo_size; ++k) {
+      for (k = 0; k < out_size; ++k) {
         const double cur_bits =
-            HistogramAddThresh(histograms[k], orig_histograms[i], best_bits);
-        if (cur_bits < best_bits) {
+            HistogramAddThresh(out_histo[k], in_histo[i], best_bits);
+        if (k == 0 || cur_bits < best_bits) {
           best_bits = cur_bits;
           best_out = k;
         }
@@ -833,20 +830,20 @@ static void HistogramRemap(const VP8LHistogramSet* const orig_histo,
       symbols[i] = best_out;
     }
   } else {
-    assert(image_histo_size == 1);
-    for (i = 0; i < orig_histo_size; ++i) {
+    assert(out_size == 1);
+    for (i = 0; i < in_size; ++i) {
       symbols[i] = 0;
     }
   }
 
   // Recompute each out based on raw and symbols.
-  for (i = 0; i < image_histo_size; ++i) {
-    HistogramClear(histograms[i]);
+  for (i = 0; i < out_size; ++i) {
+    HistogramClear(out_histo[i]);
   }
 
-  for (i = 0; i < orig_histo_size; ++i) {
+  for (i = 0; i < in_size; ++i) {
     const int idx = symbols[i];
-    VP8LHistogramAdd(orig_histograms[i], histograms[idx], histograms[idx]);
+    VP8LHistogramAdd(in_histo[i], out_histo[idx], out_histo[idx]);
   }
 }
 
@@ -920,11 +917,10 @@ int VP8LGetHistoImageSymbols(int xsize, int ysize,
     const float x = quality / 100.f;
     // cubic ramp between 1 and MAX_HISTO_GREEDY:
     const int threshold_size = (int)(1 + (x * x * x) * (MAX_HISTO_GREEDY - 1));
-    cur_combo = HistogramCombineStochastic(image_histo,
-                                           tmp_histos->histograms[0],
-                                           cur_combo, quality, threshold_size);
+    HistogramCombineStochastic(image_histo, tmp_histos->histograms[0],
+                               cur_combo, quality, threshold_size);
     if ((image_histo->size <= threshold_size) &&
-        !HistogramCombineGreedy(image_histo, cur_combo)) {
+        !HistogramCombineGreedy(image_histo)) {
       goto Error;
     }
   }

src/enc/near_lossless.c

@@ -14,6 +14,7 @@
 // Author: Jyrki Alakuijala (jyrki@google.com)
 // Converted to C by Aleksander Kramarz (akramarz@google.com)
 
+#include <assert.h>
 #include <stdlib.h>
 
 #include "../dsp/lossless.h"
@@ -23,42 +24,14 @@
 #define MIN_DIM_FOR_NEAR_LOSSLESS 64
 #define MAX_LIMIT_BITS             5
 
-// Computes quantized pixel value and distance from original value.
-static void GetValAndDistance(int a, int initial, int bits,
-                              int* const val, int* const distance) {
-  const int mask = ~((1 << bits) - 1);
-  *val = (initial & mask) | (initial >> (8 - bits));
-  *distance = 2 * abs(a - *val);
-}
-
-// Clamps the value to range [0, 255].
-static int Clamp8b(int val) {
-  const int min_val = 0;
-  const int max_val = 0xff;
-  return (val < min_val) ? min_val : (val > max_val) ? max_val : val;
-}
-
-// Quantizes values {a, a+(1<<bits), a-(1<<bits)} and returns the nearest one.
+// Quantizes the value up or down to a multiple of 1<<bits (or to 255),
+// choosing the closer one, resolving ties using bankers' rounding.
 static int FindClosestDiscretized(int a, int bits) {
-  int best_val = a, i;
-  int min_distance = 256;
-
-  for (i = -1; i <= 1; ++i) {
-    int candidate, distance;
-    const int val = Clamp8b(a + i * (1 << bits));
-    GetValAndDistance(a, val, bits, &candidate, &distance);
-    if (i != 0) {
-      ++distance;
-    }
-    // Smallest distance but favor i == 0 over i == -1 and i == 1
-    // since that keeps the overall intensity more constant in the
-    // images.
-    if (distance < min_distance) {
-      min_distance = distance;
-      best_val = candidate;
-    }
-  }
-  return best_val;
+  const int mask = (1 << bits) - 1;
+  const int biased = a + (mask >> 1) + ((a >> bits) & 1);
+  assert(bits > 0);
+  if (biased > 0xff) return 0xff;
+  return biased & ~mask;
 }
 
 // Applies FindClosestDiscretized to all channels of pixel.
@@ -124,22 +97,11 @@ static void NearLossless(int xsize, int ysize, uint32_t* argb,
   }
 }
 
-static int QualityToLimitBits(int quality) {
-  // quality mapping:
-  //  0..19 -> 5
-  //  0..39 -> 4
-  //  0..59 -> 3
-  //  0..79 -> 2
-  //  0..99 -> 1
-  //  100   -> 0
-  return MAX_LIMIT_BITS - quality / 20;
-}
-
 int VP8ApplyNearLossless(int xsize, int ysize, uint32_t* argb, int quality) {
   int i;
   uint32_t* const copy_buffer =
       (uint32_t*)WebPSafeMalloc(xsize * 3, sizeof(*copy_buffer));
-  const int limit_bits = QualityToLimitBits(quality);
+  const int limit_bits = VP8LNearLosslessBits(quality);
   assert(argb != NULL);
   assert(limit_bits >= 0);
   assert(limit_bits <= MAX_LIMIT_BITS);