Mux API change:

Create common APIs for image, frame and tile.

Change-Id: I709ad752133094bd5bc89dd9c832ff79802aac68

README.mux

@@ -94,7 +94,7 @@ Example#2 (pseudo code): Get image & color profile data from a WebP file.
   int copy_data = 0;
   // ... (Read data from file).
   WebPMux* mux = WebPMuxCreate(&data, copy_data);
-  WebPMuxGetImage(mux, &image);
+  WebPMuxGetFrame(mux, 1, &image);
   // ... (Consume image; e.g. call WebPDecode() to decode the data).
   WebPMuxGetChunk(mux, "ICCP", &icc_profile);
   // ... (Consume icc_profile).

examples/webpmux.c

@@ -142,6 +142,12 @@ static int IsNotCompatible(int count1, int count2) {
     return err;                                                      \
   }
 
+#define RETURN_IF_ERROR3(ERR_MSG, FORMAT_STR1, FORMAT_STR2)          \
+  if (err != WEBP_MUX_OK) {                                          \
+    fprintf(stderr, ERR_MSG, FORMAT_STR1, FORMAT_STR2);              \
+    return err;                                                      \
+  }
+
 #define ERROR_GOTO1(ERR_MSG, LABEL)                                  \
   do {                                                               \
     fprintf(stderr, ERR_MSG);                                        \
@@ -183,51 +189,36 @@ static WebPMuxError DisplayInfo(const WebPMux* mux) {
   if (flag & ALPHA_FLAG)     printf(" transparency");
   printf("\n");
 
-  if (flag & ANIMATION_FLAG) {
+  if ((flag & ANIMATION_FLAG) || (flag & TILE_FLAG)) {
+    const int is_anim = !!(flag & ANIMATION_FLAG);
+    const WebPChunkId id = is_anim ? WEBP_CHUNK_FRAME : WEBP_CHUNK_TILE;
+    const char* const type_str = is_anim ? "frame" : "tile";
     int nFrames;
+
+    if (is_anim) {
       int loop_count;
       err = WebPMuxGetLoopCount(mux, &loop_count);
       RETURN_IF_ERROR("Failed to retrieve loop count\n");
       printf("Loop Count : %d\n", loop_count);
+    }
 
-    err = WebPMuxNumChunks(mux, WEBP_CHUNK_FRAME, &nFrames);
+    err = WebPMuxNumChunks(mux, id, &nFrames);
-    RETURN_IF_ERROR("Failed to retrieve number of frames\n");
+    RETURN_IF_ERROR2("Failed to retrieve number of %ss\n", type_str);
 
-    printf("Number of frames: %d\n", nFrames);
+    printf("Number of %ss: %d\n", type_str, nFrames);
     if (nFrames > 0) {
       int i;
-      printf("No.: x_offset y_offset duration image_size");
+      printf("No.: x_offset y_offset ");
-      printf("\n");
+      if (is_anim) printf("duration ");
+      printf("image_size\n");
       for (i = 1; i <= nFrames; i++) {
         WebPMuxFrameInfo frame;
         err = WebPMuxGetFrame(mux, i, &frame);
-        RETURN_IF_ERROR2("Failed to retrieve frame#%d\n", i);
+        RETURN_IF_ERROR3("Failed to retrieve %s#%d\n", type_str, i);
-        printf("%3d: %8d %8d %8d %10zu", i, frame.x_offset_, frame.y_offset_,
+        printf("%3d: %8d %8d ", i, frame.x_offset_, frame.y_offset_);
-               frame.duration_, frame.bitstream_.size_);
+        if (is_anim) printf("%8d ", frame.duration_);
+        printf("%10zu\n", frame.bitstream_.size_);
         WebPDataClear(&frame.bitstream_);
-        printf("\n");
-      }
-    }
-  }
-
-  if (flag & TILE_FLAG) {
-    int nTiles;
-    err = WebPMuxNumChunks(mux, WEBP_CHUNK_TILE, &nTiles);
-    RETURN_IF_ERROR("Failed to retrieve number of tiles\n");
-
-    printf("Number of tiles: %d\n", nTiles);
-    if (nTiles > 0) {
-      int i;
-      printf("No.: x_offset y_offset image_size");
-      printf("\n");
-      for (i = 1; i <= nTiles; i++) {
-        WebPMuxFrameInfo tile;
-        err = WebPMuxGetTile(mux, i, &tile);
-        RETURN_IF_ERROR2("Failed to retrieve tile#%d\n", i);
-        printf("%3d: %8d %8d %10zu",
-               i, tile.x_offset_, tile.y_offset_, tile.bitstream_.size_);
-        WebPDataClear(&tile.bitstream_);
-        printf("\n");
       }
     }
   }
@@ -247,10 +238,10 @@ static WebPMuxError DisplayInfo(const WebPMux* mux) {
   }
 
   if ((flag & ALPHA_FLAG) && !(flag & (ANIMATION_FLAG | TILE_FLAG))) {
-    WebPData bitstream;
+    WebPMuxFrameInfo image;
-    err = WebPMuxGetImage(mux, &bitstream);
+    err = WebPMuxGetFrame(mux, 1, &image);
     RETURN_IF_ERROR("Failed to retrieve the image\n");
-    printf("Size of the image (with alpha): %zu\n", bitstream.size_);
+    printf("Size of the image (with alpha): %zu\n", image.bitstream_.size_);
   }
 
   return WEBP_MUX_OK;
@@ -693,6 +684,7 @@ static int GetFrameTile(const WebPMux* mux,
   WebPMux* mux_single = NULL;
   long num = 0;
   int ok = 1;
+  const WebPChunkId id = isFrame ? WEBP_CHUNK_FRAME : WEBP_CHUNK_TILE;
   WebPMuxFrameInfo info;
   WebPDataInit(&info.bitstream_);
 
@@ -701,19 +693,12 @@ static int GetFrameTile(const WebPMux* mux,
     ERROR_GOTO1("ERROR: Frame/Tile index must be non-negative.\n", ErrGet);
   }
 
-  if (isFrame) {
   err = WebPMuxGetFrame(mux, num, &info);
+  if (err == WEBP_MUX_OK && info.id != id) err = WEBP_MUX_NOT_FOUND;
   if (err != WEBP_MUX_OK) {
     ERROR_GOTO3("ERROR (%s): Could not get frame %ld.\n",
                 ErrorString(err), num, ErrGet);
   }
-  } else {
-    err = WebPMuxGetTile(mux, num, &info);
-    if (err != WEBP_MUX_OK) {
-      ERROR_GOTO3("ERROR (%s): Could not get frame %ld.\n",
-                  ErrorString(err), num, ErrGet);
-    }
-  }
 
   mux_single = WebPMuxNew();
   if (mux_single == NULL) {
@@ -726,6 +711,7 @@ static int GetFrameTile(const WebPMux* mux,
     ERROR_GOTO2("ERROR (%s): Could not create single image mux object.\n",
                 ErrorString(err), ErrGet);
   }
+
   ok = WriteWebP(mux_single, config->output_);
 
  ErrGet:
@@ -808,6 +794,7 @@ static int Process(const WebPMuxConfig* config) {
                 WebPDataClear(&frame.bitstream_);
                 ERROR_GOTO1("ERROR: Could not parse frame properties.\n", Err2);
               }
+              frame.id = WEBP_CHUNK_FRAME;
               err = WebPMuxPushFrame(mux, &frame, 1);
               WebPDataClear(&frame.bitstream_);
               if (err != WEBP_MUX_OK) {
@@ -836,7 +823,8 @@ static int Process(const WebPMuxConfig* config) {
               WebPDataClear(&tile.bitstream_);
               ERROR_GOTO1("ERROR: Could not parse tile properties.\n", Err2);
             }
-            err = WebPMuxPushTile(mux, &tile, 1);
+            tile.id = WEBP_CHUNK_TILE;
+            err = WebPMuxPushFrame(mux, &tile, 1);
             WebPDataClear(&tile.bitstream_);
             if (err != WEBP_MUX_OK) {
               ERROR_GOTO3("ERROR (%s): Could not add a tile at index %d.\n",

src/mux/muxedit.c

@@ -205,61 +205,6 @@ static WebPMuxError DeleteLoopCount(WebPMux* const mux) {
 //------------------------------------------------------------------------------
 // Set API(s).
 
-WebPMuxError WebPMuxSetImage(WebPMux* mux,
-                             const WebPData* bitstream, int copy_data) {
-  WebPMuxError err;
-  WebPChunk chunk;
-  WebPMuxImage wpi;
-  WebPData image;
-  WebPData alpha;
-  int is_lossless;
-  int image_tag;
-
-  if (mux == NULL || bitstream == NULL || bitstream->bytes_ == NULL ||
-      bitstream->size_ > MAX_CHUNK_PAYLOAD) {
-    return WEBP_MUX_INVALID_ARGUMENT;
-  }
-
-  // If given data is for a whole webp file,
-  // extract only the VP8/VP8L data from it.
-  err = GetImageData(bitstream, &image, &alpha, &is_lossless);
-  if (err != WEBP_MUX_OK) return err;
-  image_tag = is_lossless ? kChunks[IDX_VP8L].tag : kChunks[IDX_VP8].tag;
-
-  // Delete the existing images.
-  MuxImageDeleteAll(&mux->images_);
-
-  MuxImageInit(&wpi);
-
-  if (alpha.bytes_ != NULL) {  // Add alpha chunk.
-    ChunkInit(&chunk);
-    err = ChunkAssignData(&chunk, &alpha, copy_data, kChunks[IDX_ALPHA].tag);
-    if (err != WEBP_MUX_OK) goto Err;
-    err = ChunkSetNth(&chunk, &wpi.alpha_, 1);
-    if (err != WEBP_MUX_OK) goto Err;
-  }
-
-  // Add image chunk.
-  ChunkInit(&chunk);
-  err = ChunkAssignData(&chunk, &image, copy_data, image_tag);
-  if (err != WEBP_MUX_OK) goto Err;
-  err = ChunkSetNth(&chunk, &wpi.img_, 1);
-  if (err != WEBP_MUX_OK) goto Err;
-
-  // Add this image to mux.
-  err = MuxImagePush(&wpi, &mux->images_);
-  if (err != WEBP_MUX_OK) goto Err;
-
-  // All OK.
-  return WEBP_MUX_OK;
-
- Err:
-  // Something bad happened.
-  ChunkRelease(&chunk);
-  MuxImageRelease(&wpi);
-  return err;
-}
-
 WebPMuxError WebPMuxSetChunk(WebPMux* mux, const char fourcc[4],
                              const WebPData* chunk_data, int copy_data) {
   const CHUNK_INDEX idx = ChunkGetIndexFromFourCC(fourcc);
@@ -278,105 +223,60 @@ WebPMuxError WebPMuxSetChunk(WebPMux* mux, const char fourcc[4],
   return MuxSet(mux, idx, 1, chunk_data, copy_data);
 }
 
-
+// Creates a chunk from given 'data' and sets it as 1st chunk in 'chunk_list'.
-WebPMuxError WebPMuxSetLoopCount(WebPMux* mux, int loop_count) {
+static WebPMuxError AddDataToChunkList(
+    const WebPData* const data, int copy_data, uint32_t tag,
+    WebPChunk** chunk_list) {
+  WebPChunk chunk;
   WebPMuxError err;
-  uint8_t* data = NULL;
+  ChunkInit(&chunk);
-
+  err = ChunkAssignData(&chunk, data, copy_data, tag);
-  if (mux == NULL) return WEBP_MUX_INVALID_ARGUMENT;
+  if (err != WEBP_MUX_OK) goto Err;
-  if (loop_count >= MAX_LOOP_COUNT) return WEBP_MUX_INVALID_ARGUMENT;
+  err = ChunkSetNth(&chunk, chunk_list, 1);
-
+  if (err != WEBP_MUX_OK) goto Err;
-  // Delete the existing LOOP chunk(s).
+  return WEBP_MUX_OK;
-  err = DeleteLoopCount(mux);
+ Err:
-  if (err != WEBP_MUX_OK && err != WEBP_MUX_NOT_FOUND) return err;
+  ChunkRelease(&chunk);
-
-  // Add the given loop count.
-  data = (uint8_t*)malloc(kChunks[IDX_LOOP].size);
-  if (data == NULL) return WEBP_MUX_MEMORY_ERROR;
-
-  PutLE16(data, loop_count);
-  err = MuxAddChunk(mux, 1, kChunks[IDX_LOOP].tag, data,
-                    kChunks[IDX_LOOP].size, 1);
-  free(data);
   return err;
 }
 
-static WebPMuxError MuxPushFrameTileInternal(
+// Extracts image & alpha data from the given bitstream and then sets wpi.alpha_
-    WebPMux* const mux, const WebPMuxFrameInfo* const frame_tile_info,
+// and wpi.img_ appropriately.
-    int copy_data, uint32_t tag) {
+static WebPMuxError SetAlphaAndImageChunks(
-  const WebPData* bitstream;
+    const WebPData* const bitstream, int copy_data, WebPMuxImage* const wpi) {
-  int x_offset, y_offset, duration;
+  int is_lossless = 0;
-  WebPChunk chunk;
+  WebPData image, alpha;
-  WebPData image;
+  WebPMuxError err = GetImageData(bitstream, &image, &alpha, &is_lossless);
-  WebPData alpha;
+  const int image_tag =
+      is_lossless ? kChunks[IDX_VP8L].tag : kChunks[IDX_VP8].tag;
+  if (err != WEBP_MUX_OK) return err;
+  if (alpha.bytes_ != NULL) {
+    err = AddDataToChunkList(&alpha, copy_data, kChunks[IDX_ALPHA].tag,
+                             &wpi->alpha_);
+    if (err != WEBP_MUX_OK) return err;
+  }
+  return AddDataToChunkList(&image, copy_data, image_tag, &wpi->img_);
+}
+
+WebPMuxError WebPMuxSetImage(WebPMux* mux, const WebPData* bitstream,
+                             int copy_data) {
   WebPMuxImage wpi;
   WebPMuxError err;
-  WebPData frame_tile;
-  const int is_frame = (tag == kChunks[IDX_FRAME].tag) ? 1 : 0;
-  int is_lossless;
-  int image_tag;
 
   // Sanity checks.
-  if (mux == NULL || frame_tile_info == NULL) {
+  if (mux == NULL || bitstream == NULL || bitstream->bytes_ == NULL ||
+      bitstream->size_ > MAX_CHUNK_PAYLOAD) {
     return WEBP_MUX_INVALID_ARGUMENT;
   }
 
-  bitstream = &frame_tile_info->bitstream_;
+  if (mux->images_ != NULL) {
-  x_offset = frame_tile_info->x_offset_;
+    // Only one 'simple image' can be added in mux. So, remove present images.
-  y_offset = frame_tile_info->y_offset_;
+    MuxImageDeleteAll(&mux->images_);
-  duration = is_frame ? frame_tile_info->duration_ : 1 /* unused */;
-
-  if (bitstream->bytes_ == NULL || bitstream->size_ > MAX_CHUNK_PAYLOAD) {
-    return WEBP_MUX_INVALID_ARGUMENT;
-  }
-  if (x_offset < 0 || x_offset >= MAX_POSITION_OFFSET ||
-      y_offset < 0 || y_offset >= MAX_POSITION_OFFSET ||
-      (is_frame && (duration <= 0 || duration > MAX_DURATION))) {
-    return WEBP_MUX_INVALID_ARGUMENT;
   }
 
-  // Snap offsets to even positions.
-  x_offset &= ~1;
-  y_offset &= ~1;
-
-  // If given data is for a whole webp file,
-  // extract only the VP8/VP8L data from it.
-  err = GetImageData(bitstream, &image, &alpha, &is_lossless);
-  if (err != WEBP_MUX_OK) return err;
-  image_tag = is_lossless ? kChunks[IDX_VP8L].tag : kChunks[IDX_VP8].tag;
-
-  WebPDataInit(&frame_tile);
-  ChunkInit(&chunk);
   MuxImageInit(&wpi);
-
+  err = SetAlphaAndImageChunks(bitstream, copy_data, &wpi);
-  if (alpha.bytes_ != NULL) {
-    // Add alpha chunk.
-    err = ChunkAssignData(&chunk, &alpha, copy_data, kChunks[IDX_ALPHA].tag);
   if (err != WEBP_MUX_OK) goto Err;
-    err = ChunkSetNth(&chunk, &wpi.alpha_, 1);
-    if (err != WEBP_MUX_OK) goto Err;
-    ChunkInit(&chunk);  // chunk owned by wpi.alpha_ now.
-  }
-
-  // Add image chunk.
-  err = ChunkAssignData(&chunk, &image, copy_data, image_tag);
-  if (err != WEBP_MUX_OK) goto Err;
-  err = ChunkSetNth(&chunk, &wpi.img_, 1);
-  if (err != WEBP_MUX_OK) goto Err;
-  ChunkInit(&chunk);  // chunk owned by wpi.img_ now.
-
-  // Create frame/tile data.
-  err = CreateFrameTileData(&image, x_offset, y_offset, duration, is_lossless,
-                            is_frame, &frame_tile);
-  if (err != WEBP_MUX_OK) goto Err;
-
-  // Add frame/tile chunk (with copy_data = 1).
-  err = ChunkAssignData(&chunk, &frame_tile, 1, tag);
-  if (err != WEBP_MUX_OK) goto Err;
-  WebPDataClear(&frame_tile);
-  err = ChunkSetNth(&chunk, &wpi.header_, 1);
-  if (err != WEBP_MUX_OK) goto Err;
-  ChunkInit(&chunk);  // chunk owned by wpi.header_ now.
 
   // Add this WebPMuxImage to mux.
   err = MuxImagePush(&wpi, &mux->images_);
@@ -386,61 +286,103 @@ static WebPMuxError MuxPushFrameTileInternal(
   return WEBP_MUX_OK;
 
  Err:  // Something bad happened.
-  WebPDataClear(&frame_tile);
-  ChunkRelease(&chunk);
   MuxImageRelease(&wpi);
   return err;
 }
 
-WebPMuxError WebPMuxPushFrame(WebPMux* mux,
+WebPMuxError WebPMuxPushFrame(WebPMux* mux, const WebPMuxFrameInfo* frame,
-                              const WebPMuxFrameInfo* frame,
                               int copy_data) {
-  return MuxPushFrameTileInternal(mux, frame, copy_data,
+  WebPMuxImage wpi;
-                                  kChunks[IDX_FRAME].tag);
+  WebPMuxError err;
+  int is_frame;
+  const WebPData* const bitstream = &frame->bitstream_;
+
+  // Sanity checks.
+  if (mux == NULL || frame == NULL) return WEBP_MUX_INVALID_ARGUMENT;
+
+  is_frame = (frame->id == WEBP_CHUNK_FRAME);
+  if (!(is_frame || (frame->id == WEBP_CHUNK_TILE))) {
+    return WEBP_MUX_INVALID_ARGUMENT;
+  }
+
+  if (bitstream->bytes_ == NULL || bitstream->size_ > MAX_CHUNK_PAYLOAD) {
+    return WEBP_MUX_INVALID_ARGUMENT;
+  }
+
+  if (mux->images_ != NULL) {
+    const WebPMuxImage* const image = mux->images_;
+    const uint32_t image_id = (image->header_ != NULL) ?
+        ChunkGetIdFromTag(image->header_->tag_) : WEBP_CHUNK_IMAGE;
+    if (image_id != frame->id) {
+      return WEBP_MUX_INVALID_ARGUMENT;  // Conflicting frame types.
+    }
+  }
+
+  MuxImageInit(&wpi);
+  err = SetAlphaAndImageChunks(bitstream, copy_data, &wpi);
+  if (err != WEBP_MUX_OK) goto Err;
+  assert(wpi.img_ != NULL);  // As SetAlphaAndImageChunks() was successful.
+
+  {
+    const int is_lossless = (wpi.img_->tag_ == kChunks[IDX_VP8L].tag);
+    const int x_offset = frame->x_offset_ & ~1;  // Snap offsets to even.
+    const int y_offset = frame->y_offset_ & ~1;
+    const int duration = is_frame ? frame->duration_ : 1 /* unused */;
+    const uint32_t tag = kChunks[is_frame ? IDX_FRAME : IDX_TILE].tag;
+    WebPData frame_tile;
+    if (x_offset < 0 || x_offset >= MAX_POSITION_OFFSET ||
+        y_offset < 0 || y_offset >= MAX_POSITION_OFFSET ||
+        (duration <= 0 || duration > MAX_DURATION)) {
+      err = WEBP_MUX_INVALID_ARGUMENT;
+      goto Err;
+    }
+    err = CreateFrameTileData(&wpi.img_->data_, x_offset, y_offset, duration,
+                              is_lossless, is_frame, &frame_tile);
+    if (err != WEBP_MUX_OK) goto Err;
+    // Add frame/tile chunk (with copy_data = 1).
+    err = AddDataToChunkList(&frame_tile, 1, tag, &wpi.header_);
+    WebPDataClear(&frame_tile);  // frame_tile owned by wpi.header_ now.
+    if (err != WEBP_MUX_OK) goto Err;
+  }
+
+  // Add this WebPMuxImage to mux.
+  err = MuxImagePush(&wpi, &mux->images_);
+  if (err != WEBP_MUX_OK) goto Err;
+
+  // All is well.
+  return WEBP_MUX_OK;
+
+ Err:  // Something bad happened.
+  MuxImageRelease(&wpi);
+  return err;
 }
 
-WebPMuxError WebPMuxPushTile(WebPMux* mux,
+WebPMuxError WebPMuxSetLoopCount(WebPMux* mux, int loop_count) {
-                             const WebPMuxFrameInfo* tile,
+  WebPMuxError err;
-                             int copy_data) {
+  uint8_t data[LOOP_CHUNK_SIZE];
-  return MuxPushFrameTileInternal(mux, tile /*unused duration*/, copy_data,
+
-                                  kChunks[IDX_TILE].tag);
+  if (mux == NULL) return WEBP_MUX_INVALID_ARGUMENT;
+  if (loop_count >= MAX_LOOP_COUNT) return WEBP_MUX_INVALID_ARGUMENT;
+
+  // Delete the existing LOOP chunk(s).
+  err = DeleteLoopCount(mux);
+  if (err != WEBP_MUX_OK && err != WEBP_MUX_NOT_FOUND) return err;
+
+  // Add the given loop count.
+  PutLE16(data, loop_count);
+  return MuxAddChunk(mux, 1, kChunks[IDX_LOOP].tag, data, sizeof(data), 1);
 }
 
 //------------------------------------------------------------------------------
 // Delete API(s).
 
-WebPMuxError WebPMuxDeleteImage(WebPMux* mux) {
-  WebPMuxError err;
-
-  if (mux == NULL) return WEBP_MUX_INVALID_ARGUMENT;
-
-  err = MuxValidateForImage(mux);
-  if (err != WEBP_MUX_OK) return err;
-
-  // All well, delete image.
-  MuxImageDeleteAll(&mux->images_);
-  return WEBP_MUX_OK;
-}
-
 WebPMuxError WebPMuxDeleteChunk(WebPMux* mux, const char fourcc[4]) {
   return MuxDeleteAllNamedData(mux, ChunkGetTagFromFourCC(fourcc));
 }
 
-static WebPMuxError DeleteFrameTileInternal(WebPMux* const mux, uint32_t nth,
-                                            CHUNK_INDEX idx) {
-  const WebPChunkId id = kChunks[idx].id;
-  if (mux == NULL) return WEBP_MUX_INVALID_ARGUMENT;
-
-  assert(idx == IDX_FRAME || idx == IDX_TILE);
-  return MuxImageDeleteNth(&mux->images_, nth, id);
-}
-
 WebPMuxError WebPMuxDeleteFrame(WebPMux* mux, uint32_t nth) {
-  return DeleteFrameTileInternal(mux, nth, IDX_FRAME);
+  if (mux == NULL) return WEBP_MUX_INVALID_ARGUMENT;
-}
+  return MuxImageDeleteNth(&mux->images_, nth);
-
-WebPMuxError WebPMuxDeleteTile(WebPMux* mux, uint32_t nth) {
-  return DeleteFrameTileInternal(mux, nth, IDX_TILE);
 }
 
 //------------------------------------------------------------------------------

src/mux/muxi.h

@@ -199,6 +199,7 @@ WebPMuxImage* MuxImageDelete(WebPMuxImage* const wpi);
 void MuxImageDeleteAll(WebPMuxImage** const wpi_list);
 
 // Count number of images matching the given tag id in the 'wpi_list'.
+// If id == WEBP_CHUNK_NIL, all images will be matched.
 int MuxImageCount(const WebPMuxImage* wpi_list, WebPChunkId id);
 
 // Check if given ID corresponds to an image related chunk.
@@ -228,13 +229,12 @@ static WEBP_INLINE WebPChunk** MuxImageGetListFromId(
 // Pushes 'wpi' at the end of 'wpi_list'.
 WebPMuxError MuxImagePush(const WebPMuxImage* wpi, WebPMuxImage** wpi_list);
 
-// Delete nth image in the image list with given tag id.
+// Delete nth image in the image list.
-WebPMuxError MuxImageDeleteNth(WebPMuxImage** wpi_list, uint32_t nth,
+WebPMuxError MuxImageDeleteNth(WebPMuxImage** wpi_list, uint32_t nth);
-                               WebPChunkId id);
 
-// Get nth image in the image list with given tag id.
+// Get nth image in the image list.
 WebPMuxError MuxImageGetNth(const WebPMuxImage** wpi_list, uint32_t nth,
-                            WebPChunkId id, WebPMuxImage** wpi);
+                            WebPMuxImage** wpi);
 
 // Total size of the given image.
 size_t MuxImageDiskSize(const WebPMuxImage* const wpi);

src/mux/muxinternal.c

@@ -109,7 +109,7 @@ WebPChunk* ChunkSearchList(WebPChunk* first, uint32_t nth, uint32_t tag) {
 
 // Outputs a pointer to 'prev_chunk->next_',
 //   where 'prev_chunk' is the pointer to the chunk at position (nth - 1).
-// Returns 1 if nth chunk was found, 0 otherwise.
+// Returns true if nth chunk was found.
 static int ChunkSearchListToSet(WebPChunk** chunk_list, uint32_t nth,
                                 WebPChunk*** const location) {
   uint32_t count = 0;
@@ -275,10 +275,14 @@ int MuxImageCount(const WebPMuxImage* wpi_list, WebPChunkId id) {
   int count = 0;
   const WebPMuxImage* current;
   for (current = wpi_list; current != NULL; current = current->next_) {
+    if (id == WEBP_CHUNK_NIL) {
+      ++count;  // Special case: count all images.
+    } else {
       const WebPChunk* const wpi_chunk = *MuxImageGetListFromId(current, id);
       if (wpi_chunk != NULL) {
         const WebPChunkId wpi_chunk_id = ChunkGetIdFromTag(wpi_chunk->tag_);
-      if (wpi_chunk_id == id) ++count;
+        if (wpi_chunk_id == id) ++count;  // Count images with a matching 'id'.
+      }
     }
   }
   return count;
@@ -286,34 +290,22 @@ int MuxImageCount(const WebPMuxImage* wpi_list, WebPChunkId id) {
 
 // Outputs a pointer to 'prev_wpi->next_',
 //   where 'prev_wpi' is the pointer to the image at position (nth - 1).
-// Returns 1 if nth image with given id was found, 0 otherwise.
+// Returns true if nth image was found.
 static int SearchImageToGetOrDelete(WebPMuxImage** wpi_list, uint32_t nth,
-                                    WebPChunkId id,
                                     WebPMuxImage*** const location) {
   uint32_t count = 0;
   assert(wpi_list);
   *location = wpi_list;
 
-  // Search makes sense only for the following.
-  assert(id == WEBP_CHUNK_FRAME || id == WEBP_CHUNK_TILE ||
-         id == WEBP_CHUNK_IMAGE);
-  assert(id != WEBP_CHUNK_IMAGE || nth == 1);
-
   if (nth == 0) {
-    nth = MuxImageCount(*wpi_list, id);
+    nth = MuxImageCount(*wpi_list, WEBP_CHUNK_NIL);
     if (nth == 0) return 0;  // Not found.
   }
 
   while (*wpi_list) {
     WebPMuxImage* const cur_wpi = *wpi_list;
-    const WebPChunk* const wpi_chunk = *MuxImageGetListFromId(cur_wpi, id);
-    if (wpi_chunk != NULL) {
-      const WebPChunkId wpi_chunk_id = ChunkGetIdFromTag(wpi_chunk->tag_);
-      if (wpi_chunk_id == id) {
     ++count;
     if (count == nth) return 1;  // Found.
-      }
-    }
     wpi_list = &cur_wpi->next_;
     *location = wpi_list;
   }
@@ -361,10 +353,9 @@ void MuxImageDeleteAll(WebPMuxImage** const wpi_list) {
   }
 }
 
-WebPMuxError MuxImageDeleteNth(WebPMuxImage** wpi_list, uint32_t nth,
+WebPMuxError MuxImageDeleteNth(WebPMuxImage** wpi_list, uint32_t nth) {
-                               WebPChunkId id) {
   assert(wpi_list);
-  if (!SearchImageToGetOrDelete(wpi_list, nth, id, &wpi_list)) {
+  if (!SearchImageToGetOrDelete(wpi_list, nth, &wpi_list)) {
     return WEBP_MUX_NOT_FOUND;
   }
   *wpi_list = MuxImageDelete(*wpi_list);
@@ -375,10 +366,10 @@ WebPMuxError MuxImageDeleteNth(WebPMuxImage** wpi_list, uint32_t nth,
 // MuxImage reader methods.
 
 WebPMuxError MuxImageGetNth(const WebPMuxImage** wpi_list, uint32_t nth,
-                            WebPChunkId id, WebPMuxImage** wpi) {
+                            WebPMuxImage** wpi) {
   assert(wpi_list);
   assert(wpi);
-  if (!SearchImageToGetOrDelete((WebPMuxImage**)wpi_list, nth, id,
+  if (!SearchImageToGetOrDelete((WebPMuxImage**)wpi_list, nth,
                                 (WebPMuxImage***)&wpi_list)) {
     return WEBP_MUX_NOT_FOUND;
   }

src/mux/muxread.c

@@ -190,6 +190,8 @@ WebPMux* WebPMuxCreateInternal(const WebPData* bitstream, int copy_data,
 //------------------------------------------------------------------------------
 // Get API(s).
 
+// TODO(urvang): Change the behavior of this to return ALPHA_FLAG when the mux
+// doesn't contain a VP8X chunk, but does contain a VP8L chunk with real alpha.
 WebPMuxError WebPMuxGetFeatures(const WebPMux* mux, uint32_t* flags) {
   WebPData data;
   WebPMuxError err;
@@ -200,10 +202,7 @@ WebPMuxError WebPMuxGetFeatures(const WebPMux* mux, uint32_t* flags) {
   // Check if VP8X chunk is present.
   err = MuxGet(mux, IDX_VP8X, 1, &data);
   if (err == WEBP_MUX_NOT_FOUND) {
-    // Check if VP8/VP8L chunk is present.
+    return MuxValidateForImage(mux);  // Check if a single image is present.
-    err = WebPMuxGetImage(mux, &data);
-    WebPDataClear(&data);
-    return err;
   } else if (err != WEBP_MUX_OK) {
     return err;
   }
@@ -230,7 +229,7 @@ static uint8_t* EmitVP8XChunk(uint8_t* const dst, int width,
 }
 
 // Assemble a single image WebP bitstream from 'wpi'.
-static WebPMuxError SynthesizeBitstream(WebPMuxImage* const wpi,
+static WebPMuxError SynthesizeBitstream(const WebPMuxImage* const wpi,
                                         WebPData* const bitstream) {
   uint8_t* dst;
 
@@ -270,25 +269,6 @@ static WebPMuxError SynthesizeBitstream(WebPMuxImage* const wpi,
   return WEBP_MUX_OK;
 }
 
-WebPMuxError WebPMuxGetImage(const WebPMux* mux, WebPData* bitstream) {
-  WebPMuxError err;
-  WebPMuxImage* wpi = NULL;
-
-  if (mux == NULL || bitstream == NULL) {
-    return WEBP_MUX_INVALID_ARGUMENT;
-  }
-
-  err = MuxValidateForImage(mux);
-  if (err != WEBP_MUX_OK) return err;
-
-  // All well. Get the image.
-  err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, 1, WEBP_CHUNK_IMAGE,
-                       &wpi);
-  assert(err == WEBP_MUX_OK);  // Already tested above.
-
-  return SynthesizeBitstream(wpi, bitstream);
-}
-
 WebPMuxError WebPMuxGetChunk(const WebPMux* mux, const char fourcc[4],
                              WebPData* chunk_data) {
   const CHUNK_INDEX idx = ChunkGetIndexFromFourCC(fourcc);
@@ -306,6 +286,56 @@ WebPMuxError WebPMuxGetChunk(const WebPMux* mux, const char fourcc[4],
   }
 }
 
+static WebPMuxError MuxGetImageInternal(const WebPMuxImage* const wpi,
+                                        WebPMuxFrameInfo* const info) {
+  // Set some defaults for unrelated fields.
+  info->x_offset_ = 0;
+  info->y_offset_ = 0;
+  info->duration_ = 1;
+  // Extract data for related fields.
+  info->id = ChunkGetIdFromTag(wpi->img_->tag_);
+  return SynthesizeBitstream(wpi, &info->bitstream_);
+}
+
+static WebPMuxError MuxGetFrameTileInternal(const WebPMuxImage* const wpi,
+                                            WebPMuxFrameInfo* const frame) {
+  const int is_frame = (wpi->header_->tag_ == kChunks[IDX_FRAME].tag);
+  const CHUNK_INDEX idx = is_frame ? IDX_FRAME : IDX_TILE;
+  const WebPData* frame_tile_data;
+  assert(wpi->header_ != NULL);  // Already checked by WebPMuxGetFrame().
+  // Get frame/tile chunk.
+  frame_tile_data = &wpi->header_->data_;
+  if (frame_tile_data->size_ < kChunks[idx].size) return WEBP_MUX_BAD_DATA;
+  // Extract info.
+  frame->x_offset_ = 2 * GetLE24(frame_tile_data->bytes_ + 0);
+  frame->y_offset_ = 2 * GetLE24(frame_tile_data->bytes_ + 3);
+  frame->duration_ = is_frame ? 1 + GetLE24(frame_tile_data->bytes_ + 12) : 1;
+  frame->id = ChunkGetIdFromTag(wpi->header_->tag_);
+  return SynthesizeBitstream(wpi, &frame->bitstream_);
+}
+
+WebPMuxError WebPMuxGetFrame(
+    const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* frame) {
+  WebPMuxError err;
+  WebPMuxImage* wpi;
+
+  // Sanity checks.
+  if (mux == NULL || frame == NULL) {
+    return WEBP_MUX_INVALID_ARGUMENT;
+  }
+
+  // Get the nth WebPMuxImage.
+  err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, nth, &wpi);
+  if (err != WEBP_MUX_OK) return err;
+
+  // Get frame info.
+  if (wpi->header_ == NULL) {
+    return MuxGetImageInternal(wpi, frame);
+  } else {
+    return MuxGetFrameTileInternal(wpi, frame);
+  }
+}
+
 WebPMuxError WebPMuxGetLoopCount(const WebPMux* mux, int* loop_count) {
   WebPData image;
   WebPMuxError err;
@@ -320,49 +350,6 @@ WebPMuxError WebPMuxGetLoopCount(const WebPMux* mux, int* loop_count) {
   return WEBP_MUX_OK;
 }
 
-static WebPMuxError MuxGetFrameTileInternal(
-    const WebPMux* const mux, uint32_t nth,
-    WebPMuxFrameInfo* const frame_tile_info, uint32_t tag) {
-  const WebPData* frame_tile_data;
-  WebPMuxError err;
-  WebPMuxImage* wpi;
-
-  const int is_frame = (tag == kChunks[WEBP_CHUNK_FRAME].tag) ? 1 : 0;
-  const CHUNK_INDEX idx = is_frame ? IDX_FRAME : IDX_TILE;
-  const WebPChunkId id = kChunks[idx].id;
-
-  if (mux == NULL || frame_tile_info == NULL) {
-    return WEBP_MUX_INVALID_ARGUMENT;
-  }
-
-  // Get the nth WebPMuxImage.
-  err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, nth, id, &wpi);
-  if (err != WEBP_MUX_OK) return err;
-
-  // Get frame chunk.
-  assert(wpi->header_ != NULL);  // As MuxImageGetNth() already checked header_.
-  frame_tile_data = &wpi->header_->data_;
-
-  if (frame_tile_data->size_ < kChunks[idx].size) return WEBP_MUX_BAD_DATA;
-  frame_tile_info->x_offset_ = 2 * GetLE24(frame_tile_data->bytes_ + 0);
-  frame_tile_info->y_offset_ = 2 * GetLE24(frame_tile_data->bytes_ + 3);
-  if (is_frame) {
-    frame_tile_info->duration_ = 1 + GetLE24(frame_tile_data->bytes_ + 12);
-  }
-
-  return SynthesizeBitstream(wpi, &frame_tile_info->bitstream_);
-}
-
-WebPMuxError WebPMuxGetFrame(const WebPMux* mux, uint32_t nth,
-                             WebPMuxFrameInfo* frame) {
-  return MuxGetFrameTileInternal(mux, nth, frame, kChunks[IDX_FRAME].tag);
-}
-
-WebPMuxError WebPMuxGetTile(const WebPMux* mux, uint32_t nth,
-                            WebPMuxFrameInfo* tile) {
-  return MuxGetFrameTileInternal(mux, nth, tile, kChunks[IDX_TILE].tag);
-}
-
 // Get chunk index from chunk id. Returns IDX_NIL if not found.
 static CHUNK_INDEX ChunkGetIndexFromId(WebPChunkId id) {
   int i;

src/webp/mux.h

@@ -35,7 +35,7 @@
 //   int copy_data = 0;
 //   // ... (Read data from file).
 //   WebPMux* mux = WebPMuxCreate(&data, copy_data);
-//   WebPMuxGetImage(mux, &image);
+//   WebPMuxGetFrame(mux, 1, &image);
 //   // ... (Consume image; e.g. call WebPDecode() to decode the data).
 //   WebPMuxGetChunk(mux, "ICCP", &icc_profile);
 //   // ... (Consume icc_data).
@@ -151,8 +151,8 @@ WEBP_EXTERN(WebPMux*) WebPMuxCreateInternal(const WebPData*, int, int);
 // Creates a mux object from raw data given in WebP RIFF format.
 // Parameters:
 //   bitstream - (in) the bitstream data in WebP RIFF format
-//   copy_data - (in) value 1 indicates given data WILL copied to the mux, and
+//   copy_data - (in) value 1 indicates given data WILL be copied to the mux
-//               value 0 indicates data will NOT be copied.
+//               and value 0 indicates data will NOT be copied.
 // Returns:
 //   A pointer to the mux object created from given data - on success.
 //   NULL - In case of invalid data or memory error.
@@ -162,54 +162,12 @@ static WEBP_INLINE WebPMux* WebPMuxCreate(const WebPData* bitstream,
 }
 
 //------------------------------------------------------------------------------
-// Single Image.
+// Non-image chunks.
-
-// Sets the image in the mux object. Any existing images (including frame/tile)
-// will be removed.
-// Parameters:
-//   mux - (in/out) object in which the image is to be set
-//   bitstream - (in) can either be a raw VP8/VP8L bitstream or a single-image
-//               WebP file (non-animated and non-tiled)
-//   copy_data - (in) value 1 indicates given data WILL copied to the mux, and
-//               value 0 indicates data will NOT be copied.
-// Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL or bitstream is NULL.
-//   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
-//   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxSetImage(WebPMux* mux,
-                                          const WebPData* bitstream,
-                                          int copy_data);
-
-// Gets image data from the mux object.
-// The content of 'bitstream' is allocated using malloc(), and NOT
-// owned by the 'mux' object. It MUST be deallocated by the caller by calling
-// WebPDataClear().
-// Parameters:
-//   mux - (in) object from which the image is to be fetched
-//   bitstream - (out) the image data
-// Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if either mux or bitstream is NULL
-//                               or if mux contains animation/tiling.
-//   WEBP_MUX_NOT_FOUND - if image is not present in mux object.
-//   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxGetImage(const WebPMux* mux,
-                                          WebPData* bitstream);
-
-// Deletes the image in the mux object.
-// Parameters:
-//   mux - (in/out) object from which the image is to be deleted
-// Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL
-//                               or if mux contains animation/tiling.
-//   WEBP_MUX_NOT_FOUND - if image is not present in mux object.
-//   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxDeleteImage(WebPMux* mux);
-
-//------------------------------------------------------------------------------
-// Chunks.
 
 // Note: Only non-image related chunks should be managed through chunk APIs.
 // (Image related chunks are: "FRM ", "TILE", "VP8 ", "VP8L" and "ALPH").
+// To add, get and delete images, use APIs WebPMuxSetImage(),
+// WebPMuxPushFrame(), WebPMuxGetFrame() and WebPMuxDeleteFrame().
 
 // Adds a chunk with id 'fourcc' and data 'chunk_data' in the mux object.
 // Any existing chunk(s) with the same id will be removed.
@@ -218,8 +176,8 @@ WEBP_EXTERN(WebPMuxError) WebPMuxDeleteImage(WebPMux* mux);
 //   fourcc - (in) a character array containing the fourcc of the given chunk;
 //                 e.g., "ICCP", "META" etc.
 //   chunk_data - (in) the chunk data to be added
-//   copy_data - (in) value 1 indicates given data WILL copied to the mux, and
+//   copy_data - (in) value 1 indicates given data WILL be copied to the mux
-//               value 0 indicates data will NOT be copied.
+//               and value 0 indicates data will NOT be copied.
 // Returns:
 //   WEBP_MUX_INVALID_ARGUMENT - if mux or chunk_data is NULL
 //                               or if fourcc corresponds to an image chunk.
@@ -258,7 +216,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxDeleteChunk(
     WebPMux* mux, const char fourcc[4]);
 
 //------------------------------------------------------------------------------
-// Animation.
+// Images.
 
 // Encapsulates data about a single frame/tile.
 struct WebPMuxFrameInfo {
@@ -267,17 +225,39 @@ struct WebPMuxFrameInfo {
   int         x_offset_;   // x-offset of the frame.
   int         y_offset_;   // y-offset of the frame.
   int         duration_;   // duration of the frame (in milliseconds).
+
+  WebPChunkId id;          // frame type: should be one of WEBP_CHUNK_FRAME,
+                           // WEBP_CHUNK_TILE or WEBP_CHUNK_IMAGE
   uint32_t pad[3];         // padding for later use
 };
 
-// Adds an animation frame at the end of the mux object.
+// Sets the (non-animated and non-tiled) image in the mux object.
-// Note: as WebP only supports even offsets, any odd offset will be snapped to
+// Note: Any existing images (including frames/tiles) will be removed.
-// an even location using: offset &= ~1
 // Parameters:
-//   mux - (in/out) object to which an animation frame is to be added
+//   mux - (in/out) object in which the image is to be set
+//   bitstream - (in) can either be a raw VP8/VP8L bitstream or a single-image
+//               WebP file (non-animated and non-tiled)
+//   copy_data - (in) value 1 indicates given data WILL be copied to the mux
+//               and value 0 indicates data will NOT be copied.
+// Returns:
+//   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL or bitstream is NULL.
+//   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
+//   WEBP_MUX_OK - on success.
+WEBP_EXTERN(WebPMuxError) WebPMuxSetImage(
+    WebPMux* mux, const WebPData* bitstream, int copy_data);
+
+// Adds a frame at the end of the mux object.
+// Notes: (1) frame.id should be one of WEBP_CHUNK_FRAME or WEBP_CHUNK_TILE
+//        (2) For setting a non-animated non-tiled image, use WebPMuxSetImage()
+//            instead.
+//        (3) Type of frame being pushed must be same as the frames in mux.
+//        (4) As WebP only supports even offsets, any odd offset will be snapped
+//            to an even location using: offset &= ~1
+// Parameters:
+//   mux - (in/out) object to which the frame is to be added
 //   frame - (in) frame data.
-//   copy_data - (in) value 1 indicates given data WILL copied to the mux, and
+//   copy_data - (in) value 1 indicates given data WILL be copied to the mux
-//               value 0 indicates data will NOT be copied.
+//               and value 0 indicates data will NOT be copied.
 // Returns:
 //   WEBP_MUX_INVALID_ARGUMENT - if mux or frame is NULL
 //                               or if content of 'frame' is invalid.
@@ -286,7 +266,7 @@ struct WebPMuxFrameInfo {
 WEBP_EXTERN(WebPMuxError) WebPMuxPushFrame(
     WebPMux* mux, const WebPMuxFrameInfo* frame, int copy_data);
 
-// Gets the nth animation frame from the mux object.
+// Gets the nth frame from the mux object.
 // The content of 'frame->bitstream_' is allocated using malloc(), and NOT
 // owned by the 'mux' object. It MUST be deallocated by the caller by calling
 // WebPDataClear().
@@ -296,25 +276,28 @@ WEBP_EXTERN(WebPMuxError) WebPMuxPushFrame(
 //   nth - (in) index of the frame in the mux object
 //   frame - (out) data of the returned frame
 // Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if mux or frame is NULL
+//   WEBP_MUX_INVALID_ARGUMENT - if mux or frame is NULL.
 //   WEBP_MUX_NOT_FOUND - if there are less than nth frames in the mux object.
 //   WEBP_MUX_BAD_DATA - if nth frame chunk in mux is invalid.
 //   WEBP_MUX_OK - on success.
 WEBP_EXTERN(WebPMuxError) WebPMuxGetFrame(
     const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* frame);
 
-// Deletes an animation frame from the mux object.
+// Deletes a frame from the mux object.
 // nth=0 has a special meaning - last position.
 // Parameters:
 //   mux - (in/out) object from which a frame is to be deleted
 //   nth - (in) The position from which the frame is to be deleted
 // Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL
+//   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL.
 //   WEBP_MUX_NOT_FOUND - If there are less than nth frames in the mux object
 //                        before deletion.
 //   WEBP_MUX_OK - on success.
 WEBP_EXTERN(WebPMuxError) WebPMuxDeleteFrame(WebPMux* mux, uint32_t nth);
 
+//------------------------------------------------------------------------------
+// Animation.
+
 // Sets the animation loop count in the mux object. Any existing loop count
 // value(s) will be removed.
 // Parameters:
@@ -338,54 +321,6 @@ WEBP_EXTERN(WebPMuxError) WebPMuxSetLoopCount(WebPMux* mux, int loop_count);
 WEBP_EXTERN(WebPMuxError) WebPMuxGetLoopCount(const WebPMux* mux,
                                               int* loop_count);
 
-//------------------------------------------------------------------------------
-// Tiling.
-
-// Adds a tile at the end of the mux object.
-// Note: as WebP only supports even offsets, any odd offset will be snapped to
-// an even location using: offset &= ~1
-// Parameters:
-//   mux - (in/out) object to which a tile is to be added.
-//   tile - (in) tile data.
-//   copy_data - (in) value 1 indicates given data WILL copied to the mux, and
-//               value 0 indicates data will NOT be copied.
-// Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if mux or tile is NULL
-//                               or if content of 'tile' is invalid.
-//   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
-//   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxPushTile(
-    WebPMux* mux, const WebPMuxFrameInfo* tile, int copy_data);
-
-// Gets the nth tile from the mux object.
-// The content of 'tile->bitstream_' is allocated using malloc(), and NOT
-// owned by the 'mux' object. It MUST be deallocated by the caller by calling
-// WebPDataClear().
-// nth=0 has a special meaning - last position.
-// Parameters:
-//   mux - (in) object from which the info is to be fetched
-//   nth - (in) index of the tile in the mux object
-//   tile - (out) data of the returned tile
-// Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if either mux or tile is NULL
-//   WEBP_MUX_NOT_FOUND - if there are less than nth tiles in the mux object.
-//   WEBP_MUX_BAD_DATA - if nth tile chunk in mux is invalid.
-//   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxGetTile(
-    const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* tile);
-
-// Deletes a tile from the mux object.
-// nth=0 has a special meaning - last position
-// Parameters:
-//   mux - (in/out) object from which a tile is to be deleted
-//   nth - (in) The position from which the tile is to be deleted
-// Returns:
-//   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL
-//   WEBP_MUX_NOT_FOUND - If there are less than nth tiles in the mux object
-//                        before deletion.
-//   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxDeleteTile(WebPMux* mux, uint32_t nth);
-
 //------------------------------------------------------------------------------
 // Misc Utilities.