Update ChangeLog

Change-Id: I381ab93458df3d1851aec36161cc4b2cbd1265be

ChangeLog

@@ -1,3 +1,24 @@
+d52b405 Cosmetic fixes
+6cb4a61 misc style fix
+68111ab add missing YUVA->ARGB automatic conversion in WebPEncode()
+403bfe8 Container spec: Clarify frame disposal
+3e7a13a Merge "Container spec: clarify the background color field" into 0.3.0
+14af774 container doc: add a note about the 'ANMF' payload
+cc635ef Container spec: clarify the background color field
+e3e3394 container doc: move RIFF description to own section
+4299f39 libwebp/mux: fix double free
+33f9a69 Merge "demux: keep a frame tail pointer; used in AddFrame" into 0.3.0
+a2a7b95 use WebPDataCopy() instead of re-coding it.
+6f18f12 demux: keep a frame tail pointer; used in AddFrame
+e5af49e add doc precision about WebPParseHeaders() return codes
+db46daa Merge "Makefile.vc: fix dynamic builds" into 0.3.0
+53c77af Merge "gif2webp: Bgcolor fix for a special case" into 0.3.0
+a5ebd14 gif2webp: Bgcolor fix for a special case
+6378f23 Merge "vwebp/animation: fix background dispose" into 0.3.0
+3c8eb9a fix bad saturation order in QuantizeBlock
+04c7a2e vwebp/animation: fix background dispose
+81a5069 Makefile.vc: fix dynamic builds
+5f25c39 update ChangeLog
 14d42af examples: don't use C99 %zu
 5ccf1fe update ChangeLog
 2560c24 update NEWS

Makefile.vc

@@ -105,7 +105,7 @@ DLLC   = webp_dll.c
 DLLINC = webp_dll.h
 DLL_OBJS = $(DIROBJ)\$(DLLC:.c=.obj)
 CC     = $(CC) /I$(DIROBJ) /FI$(DLLINC) $(RTLIB) /DWEBP_DLL
-LIBWEBP = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME)_dll.lib
+LIBWEBPDECODER = $(DIRLIB)\$(LIBWEBPDECODER_BASENAME)_dll.lib
 LIBWEBP = $(DIRLIB)\$(LIBWEBP_BASENAME)_dll.lib
 LIBWEBPMUX = $(DIRLIB)\$(LIBWEBPMUX_BASENAME)_dll.lib
 LIBWEBPDEMUX = $(DIRLIB)\$(LIBWEBPMDEMUX_BASENAME)_dll.lib
@@ -261,7 +261,7 @@ $(LIBWEBPDEMUX): $(LIBWEBPDEMUX_OBJS)
 $(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS): $(OUTPUT_DIRS)
 
 !IF "$(DLLBUILD)" == "TRUE"
-$(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS):
+$(LIBWEBP_OBJS) $(LIBWEBPMUX_OBJS) $(LIBWEBPDEMUX_OBJS): \
     $(DIROBJ)\$(DLLINC) $(DIROBJ)\$(DLLC)
 
 {$(DIROBJ)}.c{$(DIROBJ)}.obj:

doc/webp-container-spec.txt

@@ -93,11 +93,21 @@ _uint32_
 
 : A 32-bit, little-endian, unsigned integer.
 
+_FourCC_
+
+: A _FourCC_ (four-character code) is a _uint32_ created by concatenating four
+  ASCII characters in little-endian order.
+
 _1-based_
 
 : An unsigned integer field storing values offset by `-1`. e.g., Such a field
 would store value _25_ as _24_.
 
+RIFF file format
+----------------
+The WebP file format is based on the RIFF (resource interchange file format)
+document format.
+
 The basic element of a RIFF file is a _chunk_. It consists of:
 
      0                   1                   2                   3
@@ -112,12 +122,12 @@ The basic element of a RIFF file is a _chunk_. It consists of:
 
 Chunk FourCC: 32 bits
 
-: ASCII four character code or _chunk tag_ used for chunk identification.
+: ASCII four-character code used for chunk identification.
 
 Chunk Size: 32 bits (_uint32_)
 
-: The size of the chunk (_ckSize_) not including this field, the chunk
-  identifier and padding.
+: The size of the chunk not including this field, the chunk identifier or
+  padding.
 
 Chunk Payload: _Chunk Size_ bytes
 
@@ -126,43 +136,13 @@ Chunk Payload: _Chunk Size_ bytes
 
 _ChunkHeader('ABCD')_
 
-: This is used to describe the fourcc and size header of individual
-  chunks, where 'ABCD' is the fourcc for the chunk. This element's
+: This is used to describe the _FourCC_ and _Chunk Size_ header of individual
+  chunks, where 'ABCD' is the FourCC for the chunk. This element's
   size is 8 bytes.
 
-: Note that, in this specification, all chunk tag characters are in
-  file order, not in byte order of a uint32 of any particular
-  architecture.
-
-_list of chunks_
-
-: A concatenation of multiple chunks.
-
-: We will refer to the first chunk as having _position_ 0, the second
-  as position 1, etc. By _chunk with index 0 among "ABCD"_ we mean
-  the first chunk among the chunks of type "ABCD" in the list, the
-  _chunk with index 1 among "ABCD"_ is the second such chunk, etc.
-
-A WebP file MUST begin with a single chunk with a tag 'RIFF'. All
-other defined chunks are contained within this chunk. The file SHOULD
-NOT contain anything after it.
-
-The maximum size of RIFF's _ckSize_ is 2^32 minus 10 bytes. The size
-of the whole file is at most 4GiB minus 2 bytes.
-
-**Note:** some RIFF libraries are said to have bugs when handling files
-larger than 1GiB or 2GiB. If you are using an existing library, check
-that it handles large files correctly.
-
-The first four bytes of the RIFF chunk contents (i.e., bytes 8-11 of the file)
-MUST be the ASCII string "WEBP". They are followed by a list of chunks. As the
-size of any chunk is even, the size of the RIFF chunk is also even.  The
-contents of the chunks in that list will be described in the following sections.
-
-**Note:** RIFF has a convention that all-uppercase chunks are standard
-chunks that apply to any RIFF file format, while chunks specific to a
-file format are all lowercase. WebP does not follow this convention.
-
+**Note:** RIFF has a convention that all-uppercase chunk FourCCs are standard
+chunks that apply to any RIFF file format, while FourCCs specific to a file
+format are all lowercase. WebP does not follow this convention.
 
 WebP file header
 ----------------
@@ -183,12 +163,20 @@ WebP file header
 
 File Size: 32 bits (_uint32_)
 
-: The size of the file in bytes starting at offset 8.
+: The size of the file in bytes starting at offset 8. The maximum value of
+this field is 2^32 minus 10 bytes and thus the size of the whole file is at
+most 4GiB minus 2 bytes.
 
 'WEBP': 32 bits
 
 : The ASCII characters 'W' 'E' 'B' 'P'.
 
+A WebP file MUST begin with a RIFF header with the FourCC 'WEBP'. The file size
+in the header is the total size of the chunks that follow plus `4` bytes for
+the 'WEBP' FourCC. The file SHOULD NOT contain anything after it. As the size
+of any chunk is even, the size given by the RIFF header is also even. The
+contents of individual chunks will be described in the following sections.
+
 Simple file format (lossy)
 --------------------------
 
@@ -376,6 +364,7 @@ Future specifications MAY add more fields.
 An animation is controlled by ANIM and ANMF chunks.
 
 ANIM Chunk:
+{:#anim_chunk}
 
 For an animated image, this chunk contains the _global parameters_ of the
 animation.
@@ -392,10 +381,14 @@ animation.
 
 Background Color: 32 bits (_uint32_)
 
-: The background color of the canvas in \[Blue, Green, Red, Alpha\] byte order.
-The background color is the color used for those pixels of the canvas that are
-not covered by a frame. Background color is also used when disposal method is
-`1`.
+: The default background color of the canvas in \[Blue, Green, Red, Alpha\]
+byte order. This color is used to fill the unused space on the canvas around the
+frames, as well as the transparent pixels of the first frame. Background color
+is also used when disposal method is `1`.
+
+**Note**: Viewers that have a preferred background against which to present the
+images (web browsers, for example) should ignore this value and use their
+preferred background color instead.
 
 Loop Count: 16 bits (_uint16_)
 
@@ -457,14 +450,45 @@ Reserved: 7 bits
 
 Disposal method (D): 1 bit
 
-: Indicates how the area used by this frame is to be treated before rendering
-the next frame on canvas:
+: Indicates how _the current frame_ is to be treated after it has been displayed
+(before rendering the next frame) on the canvas:
 
-  * `0`: Do not dispose. Keep the area used by this frame as it is and render
-    the next frame on top of it.
+  * `0`: Do not dispose. Leave the canvas as is.
 
-  * `1`: Dispose to background color (also part of this chunk). Restore the
-    area used by this frame to background color before rendering the next frame.
+  * `1`: Dispose to background color. Fill the _rectangle_ on the canvas covered
+    by the _current frame_ with background color specified in the
+    [ANIM chunk](#anim_chunk).
+
+After disposing the current frame, render the next frame on the canvas using
+[alpha-blending](#alpha-blending). If the next frame does not have an alpha
+channel, assume alpha value of 255, effectively replacing the rectangle.
+
+**Notes**:
+
+  * The frame disposal only applies to the _frame rectangle_, that is, the
+    rectangle defined by _Frame X_, _Frame Y_, _frame width_ and _frame height_.
+    It may or may not cover the whole canvas.
+
+{:#alpha-blending}
+  * **Alpha-blending**:
+
+    Given that each of the R, G, B and A channels is 8-bit, and the RGB
+    channels are _not premultiplied_ by alpha, the formula for blending
+    'dst' onto 'src' is:
+
+~~~~~
+    blend.A = src.A + dst.A * (1 - src.A / 255)
+    if blend.A = 0 then
+      blend.RGB = 0
+    else
+      blend.RGB = (src.RGB * src.A +
+                   dst.RGB * dst.A * (1 - src.A / 255)) / blend.A
+~~~~~
+
+  * Alpha-blending SHOULD be done in linear color space, by taking into account
+    the [color profile](#color-profile) of the image. If the color profile is
+    not present, sRGB is to be assumed. (Note that sRGB also needs to be
+    linearized due to a gamma of ~2.2).
 
 Frame Data: _Chunk Size_ - `16` bytes
 
@@ -478,6 +502,9 @@ Frame Data: _Chunk Size_ - `16` bytes
 
   * An optional list of [unknown chunks](#unknown-chunks).
 
+**Note**: The 'ANMF' payload, _Frame Data_ above, consists of individual
+_padded_ chunks as described by the [RIFF file format](#riff-file-format).
+
 #### Fragments _\[status: experimental\]_
 
 For images that are represented by fragments, this chunk contains data for

examples/gif2webp.c

@@ -117,14 +117,17 @@ static int ReadSubImage(GifFileType* gif, WebPPicture* pic, WebPPicture* view) {
   return ok;
 }
 
-static int GetColorFromIndex(const ColorMapObject* const color_map, GifWord idx,
-                             uint32_t* const argb) {
-  assert(color_map != NULL && color_map->Colors != NULL);
-  if (idx >= color_map->ColorCount) {
-    return 0;  // Invalid index.
+static int GetBackgroundColor(const ColorMapObject* const color_map,
+                              GifWord bgcolor_idx, uint32_t* const bgcolor) {
+  if (transparent_index != -1 && bgcolor_idx == transparent_index) {
+    *bgcolor = TRANSPARENT_COLOR;  // Special case.
+    return 1;
+  } else if (color_map == NULL || color_map->Colors == NULL
+             || bgcolor_idx >= color_map->ColorCount) {
+    return 0;  // Invalid color map or index.
   } else {
-    const GifColorType color = color_map->Colors[idx];
-    *argb = (0xff        << 24)
+    const GifColorType color = color_map->Colors[bgcolor_idx];
+    *bgcolor = (0xff        << 24)
              | (color.Red   << 16)
              | (color.Green <<  8)
              | (color.Blue  <<  0);
@@ -199,6 +202,7 @@ int main(int argc, const char *argv[]) {
   WebPMuxFrameInfo frame;
   WebPMuxAnimParams anim = { WHITE_COLOR, 0 };
 
+  int is_first_frame = 1;
   int done;
   int c;
   int quiet = 0;
@@ -283,14 +287,6 @@ int main(int argc, const char *argv[]) {
   picture.custom_ptr = &memory;
   if (!WebPPictureAlloc(&picture)) goto End;
 
-  if (gif->SColorMap != NULL &&
-      !GetColorFromIndex(gif->SColorMap, gif->SBackGroundColor,
-                         &anim.bgcolor)) {
-    fprintf(stderr, "GIF decode warning: invalid background color index. "
-            "Assuming white background.\n");
-  }
-  ClearPicture(&picture, anim.bgcolor);
-
   mux = WebPMuxNew();
   if (mux == NULL) {
     fprintf(stderr, "ERROR: could not create a mux object.\n");
@@ -379,6 +375,15 @@ int main(int argc, const char *argv[]) {
                                  : WEBP_MUX_DISPOSE_NONE;
             }
             transparent_index = (flags & GIF_TRANSPARENT_MASK) ? data[4] : -1;
+            if (is_first_frame) {
+              if (!GetBackgroundColor(gif->SColorMap, gif->SBackGroundColor,
+                                      &anim.bgcolor)) {
+                fprintf(stderr, "GIF decode warning: invalid background color "
+                        "index. Assuming white background.\n");
+              }
+              ClearPicture(&picture, anim.bgcolor);
+              is_first_frame = 0;
+            }
             break;
           }
           case PLAINTEXT_EXT_FUNC_CODE: {

examples/vwebp.c

@@ -62,6 +62,11 @@ static struct {
   const WebPDecBuffer* pic;
   WebPDemuxer* dmux;
   WebPIterator frameiter;
+  struct {
+    int width, height;
+    int x_offset, y_offset;
+    enum WebPMuxAnimDispose dispose_method;
+  } prev_frame;
   WebPChunkIterator iccp;
 } kParams;
 
@@ -287,9 +292,31 @@ static void HandleDisplay(void) {
   glRasterPos2f(-1.f + xoff, 1.f - yoff);
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
   glPixelStorei(GL_UNPACK_ROW_LENGTH, pic->u.RGBA.stride / 4);
-  if (iter->dispose_method == WEBP_MUX_DISPOSE_BACKGROUND) {
+
+  if (kParams.prev_frame.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND) {
+    // 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).
+    const int window_x = kParams.prev_frame.x_offset;
+    const int window_y = kParams.canvas_height -
+                         kParams.prev_frame.y_offset -
+                         kParams.prev_frame.height;
+    glEnable(GL_SCISSOR_TEST);
+    // Only updated the requested area, not the whole canvas.
+    glScissor(window_x, window_y,
+              kParams.prev_frame.width, kParams.prev_frame.height);
+
     glClear(GL_COLOR_BUFFER_BIT);  // use clear color
+    DrawCheckerBoard();
+
+    glDisable(GL_SCISSOR_TEST);
   }
+  kParams.prev_frame.width = iter->width;
+  kParams.prev_frame.height = iter->height;
+  kParams.prev_frame.x_offset = iter->x_offset;
+  kParams.prev_frame.y_offset = iter->y_offset;
+  kParams.prev_frame.dispose_method = iter->dispose_method;
+
   glDrawPixels(pic->width, pic->height,
                GL_RGBA, GL_UNSIGNED_BYTE,
                (GLvoid*)pic->u.RGBA.rgba);
@@ -426,6 +453,11 @@ int main(int argc, char *argv[]) {
     printf("Canvas: %d x %d\n", kParams.canvas_width, kParams.canvas_height);
   }
 
+  kParams.prev_frame.width = kParams.canvas_width;
+  kParams.prev_frame.height = kParams.canvas_height;
+  kParams.prev_frame.x_offset = kParams.prev_frame.y_offset = 0;
+  kParams.prev_frame.dispose_method = WEBP_MUX_DISPOSE_BACKGROUND;
+
   memset(&kParams.iccp, 0, sizeof(kParams.iccp));
   kParams.has_color_profile =
       !!(WebPDemuxGetI(kParams.dmux, WEBP_FF_FORMAT_FLAGS) & ICCP_FLAG);

src/dec/webpi.h

@@ -61,10 +61,10 @@ typedef struct {
 } WebPHeaderStructure;
 
 // Skips over all valid chunks prior to the first VP8/VP8L frame header.
-// Returns VP8_STATUS_OK on success,
-//         VP8_STATUS_BITSTREAM_ERROR if an invalid header/chunk is found, and
-//         VP8_STATUS_NOT_ENOUGH_DATA if case of insufficient data.
-// In 'headers', compressed_size, offset, alpha_data, alpha_size and lossless
+// Returns: VP8_STATUS_OK, VP8_STATUS_BITSTREAM_ERROR (invalid header/chunk),
+// VP8_STATUS_NOT_ENOUGH_DATA (partial input) or VP8_STATUS_UNSUPPORTED_FEATURE
+// in the case of non-decodable features (animation for instance).
+// In 'headers', compressed_size, offset, alpha_data, alpha_size, and lossless
 // fields are updated appropriately upon success.
 VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers);
 

src/demux/demux.c

@@ -69,6 +69,7 @@ struct WebPDemuxer {
   uint32_t bgcolor_;
   int num_frames_;
   Frame* frames_;
+  Frame** frames_tail_;
   Chunk* chunks_;  // non-image chunks
 };
 
@@ -183,15 +184,12 @@ static void AddChunk(WebPDemuxer* const dmux, Chunk* const chunk) {
 // Add a frame to the end of the list, ensuring the last frame is complete.
 // Returns true on success, false otherwise.
 static int AddFrame(WebPDemuxer* const dmux, Frame* const frame) {
-  const Frame* last_frame = NULL;
-  Frame** f = &dmux->frames_;
-  while (*f != NULL) {
-    last_frame = *f;
-    f = &(*f)->next_;
-  }
+  const Frame* const last_frame = *dmux->frames_tail_;
   if (last_frame != NULL && !last_frame->complete_) return 0;
-  *f = frame;
+
+  *dmux->frames_tail_ = frame;
   frame->next_ = NULL;
+  dmux->frames_tail_ = &frame->next_;
   return 1;
 }
 
@@ -660,6 +658,7 @@ static void InitDemux(WebPDemuxer* const dmux, const MemBuffer* const mem) {
   dmux->bgcolor_ = 0xFFFFFFFF;  // White background by default.
   dmux->canvas_width_ = -1;
   dmux->canvas_height_ = -1;
+  dmux->frames_tail_ = &dmux->frames_;
   dmux->mem_ = *mem;
 }
 

src/dsp/enc.c

@@ -631,13 +631,13 @@ static int QuantizeBlock(int16_t in[16], int16_t out[16],
   for (; n < 16; ++n) {
     const int j = kZigzag[n];
     const int sign = (in[j] < 0);
-    int coeff = (sign ? -in[j] : in[j]) + mtx->sharpen_[j];
-    if (coeff > 2047) coeff = 2047;
+    const int coeff = (sign ? -in[j] : in[j]) + mtx->sharpen_[j];
     if (coeff > mtx->zthresh_[j]) {
       const int Q = mtx->q_[j];
       const int iQ = mtx->iq_[j];
       const int B = mtx->bias_[j];
       out[n] = QUANTDIV(coeff, iQ, B);
+      if (out[n] > MAX_LEVEL) out[n] = MAX_LEVEL;
       if (sign) out[n] = -out[n];
       in[j] = out[n] * Q;
       if (out[n]) last = n;

src/dsp/enc_sse2.c

@@ -776,7 +776,7 @@ static int Disto16x16SSE2(const uint8_t* const a, const uint8_t* const b,
 // Simple quantization
 static int QuantizeBlockSSE2(int16_t in[16], int16_t out[16],
                              int n, const VP8Matrix* const mtx) {
-  const __m128i max_coeff_2047 = _mm_set1_epi16(2047);
+  const __m128i max_coeff_2047 = _mm_set1_epi16(MAX_LEVEL);
   const __m128i zero = _mm_setzero_si128();
   __m128i coeff0, coeff8;
   __m128i out0, out8;
@@ -812,10 +812,6 @@ static int QuantizeBlockSSE2(int16_t in[16], int16_t out[16],
   coeff0 = _mm_add_epi16(coeff0, sharpen0);
   coeff8 = _mm_add_epi16(coeff8, sharpen8);
 
-  // if (coeff > 2047) coeff = 2047
-  coeff0 = _mm_min_epi16(coeff0, max_coeff_2047);
-  coeff8 = _mm_min_epi16(coeff8, max_coeff_2047);
-
   // out = (coeff * iQ + B) >> QFIX;
   {
     // doing calculations with 32b precision (QFIX=17)
@@ -843,9 +839,14 @@ static int QuantizeBlockSSE2(int16_t in[16], int16_t out[16],
     out_04 = _mm_srai_epi32(out_04, QFIX);
     out_08 = _mm_srai_epi32(out_08, QFIX);
     out_12 = _mm_srai_epi32(out_12, QFIX);
+
     // pack result as 16b
     out0 = _mm_packs_epi32(out_00, out_04);
     out8 = _mm_packs_epi32(out_08, out_12);
+
+    // if (coeff > 2047) coeff = 2047
+    out0 = _mm_min_epi16(out0, max_coeff_2047);
+    out8 = _mm_min_epi16(out8, max_coeff_2047);
   }
 
   // get sign back (if (sign[j]) out_n = -out_n)

src/enc/cost.c

@@ -75,7 +75,7 @@ const uint16_t VP8LevelCodes[MAX_VARIABLE_LEVEL][2] = {
 
 // fixed costs for coding levels, deduce from the coding tree.
 // This is only the part that doesn't depend on the probability state.
-const uint16_t VP8LevelFixedCosts[2048] = {
+const uint16_t VP8LevelFixedCosts[MAX_LEVEL + 1] = {
      0,  256,  256,  256,  256,  432,  618,  630,
    731,  640,  640,  828,  901,  948, 1021, 1101,
   1174, 1221, 1294, 1042, 1085, 1115, 1158, 1202,

src/enc/cost.h

@@ -18,7 +18,8 @@
 extern "C" {
 #endif
 
-extern const uint16_t VP8LevelFixedCosts[2048];   // approximate cost per level
+// approximate cost per level:
+extern const uint16_t VP8LevelFixedCosts[MAX_LEVEL + 1];
 extern const uint16_t VP8EntropyCost[256];        // 8bit fixed-point log(p)
 
 // Cost of coding one event with probability 'proba'.

src/enc/picture.c

@@ -462,7 +462,6 @@ int WebPPictureRescale(WebPPicture* pic, int width, int height) {
                  (uint8_t*)tmp.argb, width, height,
                  tmp.argb_stride * 4,
                  work, 4);
-
   }
   WebPPictureFree(pic);
   free(work);

src/enc/syntax.c

@@ -29,7 +29,6 @@ static int IsVP8XNeeded(const VP8Encoder* const enc) {
 }
 
 static int PutPaddingByte(const WebPPicture* const pic) {
-
   const uint8_t pad_byte[1] = { 0 };
   return !!pic->writer(pad_byte, 1, pic);
 }

src/enc/vp8enci.h

@@ -56,7 +56,8 @@ enum { NUM_MB_SEGMENTS = 4,
        NUM_CTX = 3,
        NUM_PROBAS = 11,
        MAX_LF_LEVELS = 64,       // Maximum loop filter level
-       MAX_VARIABLE_LEVEL = 67  // last (inclusive) level with variable cost
+       MAX_VARIABLE_LEVEL = 67,  // last (inclusive) level with variable cost
+       MAX_LEVEL = 2047          // max level (note: max codable is 2047 + 67)
      };
 
 typedef enum {   // Rate-distortion optimization levels

src/enc/webpenc.c

@@ -374,11 +374,8 @@ int WebPEncode(const WebPConfig* config, WebPPicture* pic) {
   if (!config->lossless) {
     VP8Encoder* enc = NULL;
     if (pic->y == NULL || pic->u == NULL || pic->v == NULL) {
-      if (pic->argb != NULL) {
+      // Make sure we have YUVA samples.
       if (!WebPPictureARGBToYUVA(pic, WEBP_YUV420)) return 0;
-      } else {
-        return WebPEncodingSetError(pic, VP8_ENC_ERROR_NULL_PARAMETER);
-      }
     }
 
     enc = InitVP8Encoder(config, pic);
@@ -405,8 +402,10 @@ int WebPEncode(const WebPConfig* config, WebPPicture* pic) {
     }
     ok &= DeleteVP8Encoder(enc);  // must always be called, even if !ok
   } else {
-    if (pic->argb == NULL)
-      return WebPEncodingSetError(pic, VP8_ENC_ERROR_NULL_PARAMETER);
+    // Make sure we have ARGB samples.
+    if (pic->argb == NULL && !WebPPictureYUVAToARGB(pic)) {
+      return 0;
+    }
 
     ok = VP8LEncodeImage(config, pic);  // Sets pic->error in case of problem.
   }

src/mux/muxi.h

@@ -121,7 +121,8 @@ WebPMuxError ChunkAssignData(WebPChunk* chunk, const WebPData* const data,
 
 // Sets 'chunk' at nth position in the 'chunk_list'.
 // nth = 0 has the special meaning "last of the list".
-WebPMuxError ChunkSetNth(const WebPChunk* chunk, WebPChunk** chunk_list,
+// On success ownership is transferred from 'chunk' to the 'chunk_list'.
+WebPMuxError ChunkSetNth(WebPChunk* chunk, WebPChunk** chunk_list,
                          uint32_t nth);
 
 // Releases chunk and returns chunk->next_.

src/mux/muxinternal.c

@@ -96,7 +96,7 @@ CHUNK_INDEX ChunkGetIndexFromFourCC(const char fourcc[4]) {
 
 // Returns next chunk in the chunk list with the given tag.
 static WebPChunk* ChunkSearchNextInList(WebPChunk* chunk, uint32_t tag) {
-  while (chunk && chunk->tag_ != tag) {
+  while (chunk != NULL && chunk->tag_ != tag) {
     chunk = chunk->next_;
   }
   return chunk;
@@ -105,7 +105,7 @@ static WebPChunk* ChunkSearchNextInList(WebPChunk* chunk, uint32_t tag) {
 WebPChunk* ChunkSearchList(WebPChunk* first, uint32_t nth, uint32_t tag) {
   uint32_t iter = nth;
   first = ChunkSearchNextInList(first, tag);
-  if (!first) return NULL;
+  if (first == NULL) return NULL;
 
   while (--iter != 0) {
     WebPChunk* next_chunk = ChunkSearchNextInList(first->next_, tag);
@@ -121,10 +121,10 @@ WebPChunk* ChunkSearchList(WebPChunk* first, uint32_t nth, uint32_t tag) {
 static int ChunkSearchListToSet(WebPChunk** chunk_list, uint32_t nth,
                                 WebPChunk*** const location) {
   uint32_t count = 0;
-  assert(chunk_list);
+  assert(chunk_list != NULL);
   *location = chunk_list;
 
-  while (*chunk_list) {
+  while (*chunk_list != NULL) {
     WebPChunk* const cur_chunk = *chunk_list;
     ++count;
     if (count == nth) return 1;  // Found.
@@ -149,27 +149,18 @@ WebPMuxError ChunkAssignData(WebPChunk* chunk, const WebPData* const data,
   ChunkRelease(chunk);
 
   if (data != NULL) {
-    if (copy_data) {
-      // Copy data.
-      chunk->data_.bytes = (uint8_t*)malloc(data->size);
-      if (chunk->data_.bytes == NULL) return WEBP_MUX_MEMORY_ERROR;
-      memcpy((uint8_t*)chunk->data_.bytes, data->bytes, data->size);
-      chunk->data_.size = data->size;
-
-      // Chunk is owner of data.
-      chunk->owner_ = 1;
-    } else {
-      // Don't copy data.
+    if (copy_data) {        // Copy data.
+      if (!WebPDataCopy(data, &chunk->data_)) return WEBP_MUX_MEMORY_ERROR;
+      chunk->owner_ = 1;    // Chunk is owner of data.
+    } else {                // Don't copy data.
       chunk->data_ = *data;
     }
   }
-
   chunk->tag_ = tag;
-
   return WEBP_MUX_OK;
 }
 
-WebPMuxError ChunkSetNth(const WebPChunk* chunk, WebPChunk** chunk_list,
+WebPMuxError ChunkSetNth(WebPChunk* chunk, WebPChunk** chunk_list,
                          uint32_t nth) {
   WebPChunk* new_chunk;
 
@@ -180,6 +171,7 @@ WebPMuxError ChunkSetNth(const WebPChunk* chunk, WebPChunk** chunk_list,
   new_chunk = (WebPChunk*)malloc(sizeof(*new_chunk));
   if (new_chunk == NULL) return WEBP_MUX_MEMORY_ERROR;
   *new_chunk = *chunk;
+  chunk->owner_ = 0;
   new_chunk->next_ = *chunk_list;
   *chunk_list = new_chunk;
   return WEBP_MUX_OK;
@@ -199,7 +191,7 @@ WebPChunk* ChunkDelete(WebPChunk* const chunk) {
 
 size_t ChunksListDiskSize(const WebPChunk* chunk_list) {
   size_t size = 0;
-  while (chunk_list) {
+  while (chunk_list != NULL) {
     size += ChunkDiskSize(chunk_list);
     chunk_list = chunk_list->next_;
   }
@@ -220,7 +212,7 @@ static uint8_t* ChunkEmit(const WebPChunk* const chunk, uint8_t* dst) {
 }
 
 uint8_t* ChunkListEmit(const WebPChunk* chunk_list, uint8_t* dst) {
-  while (chunk_list) {
+  while (chunk_list != NULL) {
     dst = ChunkEmit(chunk_list, dst);
     chunk_list = chunk_list->next_;
   }
@@ -281,7 +273,7 @@ static int SearchImageToGetOrDelete(WebPMuxImage** wpi_list, uint32_t nth,
     if (nth == 0) return 0;  // Not found.
   }
 
-  while (*wpi_list) {
+  while (*wpi_list != NULL) {
     WebPMuxImage* const cur_wpi = *wpi_list;
     ++count;
     if (count == nth) return 1;  // Found.
@@ -327,7 +319,7 @@ WebPMuxImage* MuxImageDelete(WebPMuxImage* const wpi) {
 }
 
 void MuxImageDeleteAll(WebPMuxImage** const wpi_list) {
-  while (*wpi_list) {
+  while (*wpi_list != NULL) {
     *wpi_list = MuxImageDelete(*wpi_list);
   }
 }
@@ -370,7 +362,7 @@ size_t MuxImageDiskSize(const WebPMuxImage* const wpi) {
 
 size_t MuxImageListDiskSize(const WebPMuxImage* wpi_list) {
   size_t size = 0;
-  while (wpi_list) {
+  while (wpi_list != NULL) {
     size += MuxImageDiskSize(wpi_list);
     wpi_list = wpi_list->next_;
   }
@@ -409,7 +401,7 @@ uint8_t* MuxImageEmit(const WebPMuxImage* const wpi, uint8_t* dst) {
 }
 
 uint8_t* MuxImageListEmit(const WebPMuxImage* wpi_list, uint8_t* dst) {
-  while (wpi_list) {
+  while (wpi_list != NULL) {
     dst = MuxImageEmit(wpi_list, dst);
     wpi_list = wpi_list->next_;
   }

src/webp/encode.h

@@ -266,7 +266,6 @@ enum WebPEncodingError {
 
 // Main exchange structure (input samples, output bytes, statistics)
 struct WebPPicture {
-
   //   INPUT
   //////////////
   // Main flag for encoder selecting between ARGB or YUV input.