prepare experimentation with yuv444 / 422

+ add a simple rescaling function: WebPPictureRescale() for encoding
+ clean-up the memory managment around the alpha plane
+ fix some includes path by using "../webp/xxx.h" instead of "webp/xxx.h"

New flags for 'cwebp':
 -resize <width> <height>
 -444  (no effect)
 -422  (no effect)
 -400

Change-Id: I25a95f901493f939c2dd789e658493b83bd1abfa

src/dec/Makefile.am

@@ -1,7 +1,8 @@
 AM_CPPFLAGS = -I$(top_srcdir)/src
 
 libwebpdecode_la_SOURCES = bits.h vp8i.h yuv.h bits.c dsp.c frame.c \
-                          quant.c tree.c vp8.c webp.c yuv.c idec.c alpha.c
+                          quant.c tree.c vp8.c webp.c yuv.c idec.c alpha.c \
+                          layer.c
 libwebpdecode_la_LDFLAGS = -version-info 0:0:0
 libwebpdecode_la_CPPFLAGS = $(USE_EXPERIMENTAL_CODE)
 libwebpdecodeinclude_HEADERS = ../webp/decode.h ../webp/decode_vp8.h ../webp/types.h

src/dec/bits.h

@@ -13,7 +13,7 @@
 #define WEBP_DEC_BITS_H_
 
 #include <assert.h>
-#include "webp/decode_vp8.h"
+#include "../webp/decode_vp8.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {

src/dec/frame.c

@@ -10,7 +10,7 @@
 // Author: Skal (pascal.massimino@gmail.com)
 
 #include <stdlib.h>
-#include "vp8i.h"
+#include "./vp8i.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {

src/dec/layer.c

@@ -0,0 +1,34 @@
+// Copyright 2011 Google Inc.
+//
+// This code is licensed under the same terms as WebM:
+//  Software License Agreement:  http://www.webmproject.org/license/software/
+//  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
+// -----------------------------------------------------------------------------
+//
+// Enhancement layer (for YUV444/422)
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <assert.h>
+#include <stdlib.h>
+#include "vp8i.h"
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+//-----------------------------------------------------------------------------
+
+int VP8DecodeLayer(VP8Decoder* const dec) {
+  assert(dec);
+  assert(dec->layer_data_size_ > 0);
+  (void)dec;
+
+  // TODO: handle enhancement layer here.
+
+  return 1;
+}
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}    // extern "C"
+#endif

src/dec/vp8.c

@@ -375,26 +375,30 @@ int VP8GetHeaders(VP8Decoder* const dec, VP8Io* const io) {
 #ifdef WEBP_EXPERIMENTAL_FEATURES
   // Extensions
   if (dec->pic_hdr_.colorspace_) {
-    const uint32_t EXT_SIZE = 4;
-    uint32_t ext_size;
-    uint8_t ext_bits;
-    const uint8_t* ext_bytes_end = buf - EXT_SIZE;
-    if (frm_hdr->partition_length_ <= EXT_SIZE) {
+    const size_t kTrailerSize = 8;
+    const uint8_t kTrailerMarker = 0x01;
+    uint8_t* const ext_buf = buf - kTrailerSize;
+    size_t size;
+
+    if (frm_hdr->partition_length_ < kTrailerSize ||
+        ext_buf[kTrailerSize - 1] != kTrailerMarker) {
+ Error:
       return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
                          "RIFF: Inconsistent extra information.");
     }
-    ext_size = (ext_bytes_end[0] << 16) | (ext_bytes_end[1] << 8)
-             | (ext_bytes_end[2]);
-    ext_bits = ext_bytes_end[3];
-    ext_bytes_end -= ext_size;
-    if (!(ext_bits & 0x01) || (ext_size + EXT_SIZE > frm_hdr->partition_length_)) {
-      return VP8SetError(dec, VP8_STATUS_BITSTREAM_ERROR,
-                         "RIFF: Inconsistent extra information.");
-    }
-    if (!!(ext_bits & 0x02)) {    // has alpha data
-      dec->alpha_data_size_ = ext_size;
-      dec->alpha_data_ = ext_bytes_end;
+    // Alpha
+    size = (ext_buf[4] << 0) | (ext_buf[5] << 8) | (ext_buf[6] << 16);
+    if (frm_hdr->partition_length_ < size + kTrailerSize) {
+      goto Error;
     }
+    dec->alpha_data_ = (size > 0) ? ext_buf - size : NULL;
+    dec->alpha_data_size_ = size;
+
+    // Layer
+    size = (ext_buf[0] << 0) | (ext_buf[1] << 8) | (ext_buf[2] << 16);
+    dec->layer_data_size_ = size;
+    dec->layer_data_ = NULL;  // will be set later
+    dec->layer_colorspace_ = ext_buf[3];
   }
 #endif
 
@@ -651,6 +655,14 @@ static int ParseFrame(VP8Decoder* const dec, VP8Io* io) {
   }
 #endif
 
+#ifdef WEBP_EXPERIMENTAL_FEATURES
+  if (dec->layer_data_size_ > 0) {
+    if (!VP8DecodeLayer(dec)) {
+      return 0;
+    }
+  }
+#endif
+
   return 1;
 }
 

src/dec/vp8i.h

@@ -244,13 +244,17 @@ struct VP8Decoder {
   uint32_t non_zero_ac_;
 
   // Filtering side-info
-  int filter_type_;                       // 0=off, 1=simple, 2=complex
+  int filter_type_;                         // 0=off, 1=simple, 2=complex
   uint8_t filter_levels_[NUM_MB_SEGMENTS];  // precalculated per-segment
 
   // extensions
   const uint8_t* alpha_data_;   // compressed alpha data (if present)
   size_t alpha_data_size_;
   uint8_t* alpha_plane_;        // output
+
+  int layer_colorspace_;
+  const uint8_t* layer_data_;   // compressed layer data (if present)
+  size_t layer_data_size_;
 };
 
 //-----------------------------------------------------------------------------
@@ -283,6 +287,9 @@ int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br);
 const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
                                       int row, int num_rows);
 
+// in layer.c
+int VP8DecodeLayer(VP8Decoder* const dec);
+
 // in dsp.c
 typedef void (*VP8Idct)(const int16_t* coeffs, uint8_t* dst);
 extern VP8Idct VP8Transform;

src/dec/webpi.h

@@ -16,7 +16,7 @@
 extern "C" {
 #endif
 
-#include "webp/decode_vp8.h"
+#include "../webp/decode_vp8.h"
 
 // Decoding output parameters.
 typedef struct {

src/dec/yuv.h

@@ -12,7 +12,7 @@
 #ifndef WEBP_DEC_YUV_H_
 #define WEBP_DEC_YUV_H_
 
-#include "webp/decode_vp8.h"
+#include "../webp/decode_vp8.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {