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Update mux code to match the spec wrt animation

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- Allow a duration of 0
- Rename LOOP chunk to ANIM and add the background color field to it.
- Add a disposal method field for each animation frame.
- Modify webpmux.c binary interface to allow the input of background color
  and disposal methods. Also make '-loop' and '-bgcolor' arguments optional
  with some default values.

Change-Id: I807372a61cdb8a0d3080ae3552caf2848070bf4d
This commit is contained in:
Urvang Joshi
2012-11-01 15:34:46 -07:00
parent d9c5fbefa4
commit fa30c86323
10 changed files with 287 additions and 162 deletions
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4
src/webp/format_constants.h
View File

@ -65,8 +65,8 @@ typedef enum {
#define CHUNK_SIZE_BYTES 4 // Size needed to store chunk's size.
#define CHUNK_HEADER_SIZE 8 // Size of a chunk header.
#define RIFF_HEADER_SIZE 12 // Size of the RIFF header ("RIFFnnnnWEBP").
#define ANMF_CHUNK_SIZE 15 // Size of a ANMF chunk.
#define LOOP_CHUNK_SIZE 2 // Size of a LOOP chunk.
#define ANMF_CHUNK_SIZE 16 // Size of an ANMF chunk.
#define ANIM_CHUNK_SIZE 6 // Size of an ANIM chunk.
#define FRGM_CHUNK_SIZE 6 // Size of a FRGM chunk.
#define VP8X_CHUNK_SIZE 10 // Size of a VP8X chunk.

56
src/webp/mux.h
View File

@ -59,8 +59,10 @@ typedef struct WebPData WebPData;
typedef enum WebPMuxError WebPMuxError;
typedef enum WebPFeatureFlags WebPFeatureFlags;
typedef enum WebPChunkId WebPChunkId;
typedef enum WebPMuxAnimDispose WebPMuxAnimDispose;
#endif
typedef struct WebPMuxFrameInfo WebPMuxFrameInfo;
typedef struct WebPMuxAnimParams WebPMuxAnimParams;
typedef struct WebPDemuxer WebPDemuxer;
#if !(defined(__cplusplus) || defined(c_plusplus))
@ -94,7 +96,7 @@ enum WebPFeatureFlags {
enum WebPChunkId {
WEBP_CHUNK_VP8X, // VP8X
WEBP_CHUNK_ICCP, // ICCP
WEBP_CHUNK_LOOP, // LOOP
WEBP_CHUNK_ANIM, // ANIM
WEBP_CHUNK_ANMF, // ANMF
WEBP_CHUNK_FRGM, // FRGM
WEBP_CHUNK_ALPHA, // ALPH
@ -220,6 +222,13 @@ WEBP_EXTERN(WebPMuxError) WebPMuxDeleteChunk(
//------------------------------------------------------------------------------
// Images.
// Dispose method (animation only). Indicates how the area used by the current
// frame is to be treated before rendering the next frame on the canvas.
enum WebPMuxAnimDispose {
WEBP_MUX_DISPOSE_NONE, // Do not dispose.
WEBP_MUX_DISPOSE_BACKGROUND // Dispose to background color.
};
// Encapsulates data about a single frame/tile.
struct WebPMuxFrameInfo {
WebPData bitstream; // image data: can either be a raw VP8/VP8L bitstream
@ -230,7 +239,8 @@ struct WebPMuxFrameInfo {
WebPChunkId id; // frame type: should be one of WEBP_CHUNK_ANMF,
// WEBP_CHUNK_FRGM or WEBP_CHUNK_IMAGE
uint32_t pad[3]; // padding for later use
WebPMuxAnimDispose dispose_method; // Disposal method for the frame.
uint32_t pad[2]; // padding for later use
};
// Sets the (non-animated and non-fragmented) image in the mux object.
@ -300,28 +310,38 @@ 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.
// Animation parameters.
struct WebPMuxAnimParams {
uint32_t bgcolor; // Background color of the canvas stored (in MSB order) as:
// Bits 00 to 07: Alpha.
// Bits 08 to 15: Red.
// Bits 16 to 23: Green.
// Bits 24 to 31: Blue.
int loop_count; // Number of times to repeat the animation [0 = infinite].
};
// Sets the animation parameters in the mux object. Any existing ANIM chunks
// will be removed.
// Parameters:
// mux - (in/out) object in which loop chunk is to be set/added
// loop_count - (in) animation loop count value.
// Note that loop_count of zero denotes infinite loop.
// mux - (in/out) object in which ANIM chunk is to be set/added
// params - (in) animation parameters.
// Returns:
// WEBP_MUX_INVALID_ARGUMENT - if mux is NULL
// WEBP_MUX_INVALID_ARGUMENT - if either mux or params is NULL
// WEBP_MUX_MEMORY_ERROR - on memory allocation error.
// WEBP_MUX_OK - on success.
WEBP_EXTERN(WebPMuxError) WebPMuxSetLoopCount(WebPMux* mux, int loop_count);
WEBP_EXTERN(WebPMuxError) WebPMuxSetAnimationParams(
WebPMux* mux, const WebPMuxAnimParams* params);
// Gets the animation loop count from the mux object.
// Gets the animation parameters from the mux object.
// Parameters:
// mux - (in) object from which the loop count is to be fetched
// loop_count - (out) the loop_count value present in the LOOP chunk
// mux - (in) object from which the animation parameters to be fetched
// params - (out) animation parameters extracted from the ANIM chunk
// Returns:
// WEBP_MUX_INVALID_ARGUMENT - if either of mux or loop_count is NULL
// WEBP_MUX_NOT_FOUND - if loop chunk is not present in mux object.
// WEBP_MUX_INVALID_ARGUMENT - if either of mux or params is NULL
// WEBP_MUX_NOT_FOUND - if ANIM chunk is not present in mux object.
// WEBP_MUX_OK - on success.
WEBP_EXTERN(WebPMuxError) WebPMuxGetLoopCount(const WebPMux* mux,
int* loop_count);
WEBP_EXTERN(WebPMuxError) WebPMuxGetAnimationParams(
const WebPMux* mux, WebPMuxAnimParams* params);
//------------------------------------------------------------------------------
// Misc Utilities.
@ -413,7 +433,8 @@ enum WebPFormatFeature {
WEBP_FF_FORMAT_FLAGS, // Extended format flags present in the 'VP8X' chunk.
WEBP_FF_CANVAS_WIDTH,
WEBP_FF_CANVAS_HEIGHT,
WEBP_FF_LOOP_COUNT
WEBP_FF_LOOP_COUNT,
WEBP_FF_BACKGROUND_COLOR
};
// Get the 'feature' value from the 'dmux'.
@ -433,6 +454,7 @@ struct WebPIterator {
int x_offset, y_offset; // offset relative to the canvas.
int width, height; // dimensions of this frame or fragment.
int duration; // display duration in milliseconds.
WebPMuxAnimDispose dispose_method; // dispose method for the frame.
int complete; // true if 'fragment' contains a full frame. partial images
// may still be decoded with the WebP incremental decoder.
WebPData fragment; // The frame or fragment given by 'frame_num' and