1// Copyright 2012 Google Inc. All Rights Reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the COPYING file in the root of the source
5// tree. An additional intellectual property rights grant can be found
6// in the file PATENTS. All contributing project authors may
7// be found in the AUTHORS file in the root of the source tree.
8// -----------------------------------------------------------------------------
9//
10// Demux API.
11// Enables extraction of image and extended format data from WebP files.
12
13// Code Example: Demuxing WebP data to extract all the frames, ICC profile
14// and EXIF/XMP metadata.
15/*
16 WebPDemuxer* demux = WebPDemux(&webp_data);
17
18 uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
19 uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
20 // ... (Get information about the features present in the WebP file).
21 uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
22
23 // ... (Iterate over all frames).
24 WebPIterator iter;
25 if (WebPDemuxGetFrame(demux, 1, &iter)) {
26 do {
27 // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(),
28 // ... and get other frame properties like width, height, offsets etc.
29 // ... see 'struct WebPIterator' below for more info).
30 } while (WebPDemuxNextFrame(&iter));
31 WebPDemuxReleaseIterator(&iter);
32 }
33
34 // ... (Extract metadata).
35 WebPChunkIterator chunk_iter;
36 if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter);
37 // ... (Consume the ICC profile in 'chunk_iter.chunk').
38 WebPDemuxReleaseChunkIterator(&chunk_iter);
39 if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter);
40 // ... (Consume the EXIF metadata in 'chunk_iter.chunk').
41 WebPDemuxReleaseChunkIterator(&chunk_iter);
42 if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter);
43 // ... (Consume the XMP metadata in 'chunk_iter.chunk').
44 WebPDemuxReleaseChunkIterator(&chunk_iter);
45 WebPDemuxDelete(demux);
46*/
47
48#ifndef WEBP_WEBP_DEMUX_H_
49#define WEBP_WEBP_DEMUX_H_
50
51#include "./decode.h" // for WEBP_CSP_MODE
52#include "./mux_types.h"
53
54#ifdef __cplusplus
55extern "C" {
56#endif
57
58#define WEBP_DEMUX_ABI_VERSION 0x0107 // MAJOR(8b) + MINOR(8b)
59
60// Note: forward declaring enumerations is not allowed in (strict) C and C++,
61// the types are left here for reference.
62// typedef enum WebPDemuxState WebPDemuxState;
63// typedef enum WebPFormatFeature WebPFormatFeature;
64typedef struct WebPDemuxer WebPDemuxer;
65typedef struct WebPIterator WebPIterator;
66typedef struct WebPChunkIterator WebPChunkIterator;
67typedef struct WebPAnimInfo WebPAnimInfo;
68typedef struct WebPAnimDecoderOptions WebPAnimDecoderOptions;
69
70//------------------------------------------------------------------------------
71
72// Returns the version number of the demux library, packed in hexadecimal using
73// 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507.
74WEBP_EXTERN int WebPGetDemuxVersion(void);
75
76//------------------------------------------------------------------------------
77// Life of a Demux object
78
79typedef enum WebPDemuxState {
80 WEBP_DEMUX_PARSE_ERROR = -1, // An error occurred while parsing.
81 WEBP_DEMUX_PARSING_HEADER = 0, // Not enough data to parse full header.
82 WEBP_DEMUX_PARSED_HEADER = 1, // Header parsing complete,
83 // data may be available.
84 WEBP_DEMUX_DONE = 2 // Entire file has been parsed.
85} WebPDemuxState;
86
87// Internal, version-checked, entry point
88WEBP_EXTERN WebPDemuxer* WebPDemuxInternal(
89 const WebPData*, int, WebPDemuxState*, int);
90
91// Parses the full WebP file given by 'data'. For single images the WebP file
92// header alone or the file header and the chunk header may be absent.
93// Returns a WebPDemuxer object on successful parse, NULL otherwise.
94static WEBP_INLINE WebPDemuxer* WebPDemux(const WebPData* data) {
95 return WebPDemuxInternal(data, 0, NULL, WEBP_DEMUX_ABI_VERSION);
96}
97
98// Parses the possibly incomplete WebP file given by 'data'.
99// If 'state' is non-NULL it will be set to indicate the status of the demuxer.
100// Returns NULL in case of error or if there isn't enough data to start parsing;
101// and a WebPDemuxer object on successful parse.
102// Note that WebPDemuxer keeps internal pointers to 'data' memory segment.
103// If this data is volatile, the demuxer object should be deleted (by calling
104// WebPDemuxDelete()) and WebPDemuxPartial() called again on the new data.
105// This is usually an inexpensive operation.
106static WEBP_INLINE WebPDemuxer* WebPDemuxPartial(
107 const WebPData* data, WebPDemuxState* state) {
108 return WebPDemuxInternal(data, 1, state, WEBP_DEMUX_ABI_VERSION);
109}
110
111// Frees memory associated with 'dmux'.
112WEBP_EXTERN void WebPDemuxDelete(WebPDemuxer* dmux);
113
114//------------------------------------------------------------------------------
115// Data/information extraction.
116
117typedef enum WebPFormatFeature {
118 WEBP_FF_FORMAT_FLAGS, // bit-wise combination of WebPFeatureFlags
119 // corresponding to the 'VP8X' chunk (if present).
120 WEBP_FF_CANVAS_WIDTH,
121 WEBP_FF_CANVAS_HEIGHT,
122 WEBP_FF_LOOP_COUNT, // only relevant for animated file
123 WEBP_FF_BACKGROUND_COLOR, // idem.
124 WEBP_FF_FRAME_COUNT // Number of frames present in the demux object.
125 // In case of a partial demux, this is the number
126 // of frames seen so far, with the last frame
127 // possibly being partial.
128} WebPFormatFeature;
129
130// Get the 'feature' value from the 'dmux'.
131// NOTE: values are only valid if WebPDemux() was used or WebPDemuxPartial()
132// returned a state > WEBP_DEMUX_PARSING_HEADER.
133// If 'feature' is WEBP_FF_FORMAT_FLAGS, the returned value is a bit-wise
134// combination of WebPFeatureFlags values.
135// If 'feature' is WEBP_FF_LOOP_COUNT, WEBP_FF_BACKGROUND_COLOR, the returned
136// value is only meaningful if the bitstream is animated.
137WEBP_EXTERN uint32_t WebPDemuxGetI(
138 const WebPDemuxer* dmux, WebPFormatFeature feature);
139
140//------------------------------------------------------------------------------
141// Frame iteration.
142
143struct WebPIterator {
144 int frame_num;
145 int num_frames; // equivalent to WEBP_FF_FRAME_COUNT.
146 int x_offset, y_offset; // offset relative to the canvas.
147 int width, height; // dimensions of this frame.
148 int duration; // display duration in milliseconds.
149 WebPMuxAnimDispose dispose_method; // dispose method for the frame.
150 int complete; // true if 'fragment' contains a full frame. partial images
151 // may still be decoded with the WebP incremental decoder.
152 WebPData fragment; // The frame given by 'frame_num'. Note for historical
153 // reasons this is called a fragment.
154 int has_alpha; // True if the frame contains transparency.
155 WebPMuxAnimBlend blend_method; // Blend operation for the frame.
156
157 uint32_t pad[2]; // padding for later use.
158 void* private_; // for internal use only.
159};
160
161// Retrieves frame 'frame_number' from 'dmux'.
162// 'iter->fragment' points to the frame on return from this function.
163// Setting 'frame_number' equal to 0 will return the last frame of the image.
164// Returns false if 'dmux' is NULL or frame 'frame_number' is not present.
165// Call WebPDemuxReleaseIterator() when use of the iterator is complete.
166// NOTE: 'dmux' must persist for the lifetime of 'iter'.
167WEBP_EXTERN int WebPDemuxGetFrame(
168 const WebPDemuxer* dmux, int frame_number, WebPIterator* iter);
169
170// Sets 'iter->fragment' to point to the next ('iter->frame_num' + 1) or
171// previous ('iter->frame_num' - 1) frame. These functions do not loop.
172// Returns true on success, false otherwise.
173WEBP_EXTERN int WebPDemuxNextFrame(WebPIterator* iter);
174WEBP_EXTERN int WebPDemuxPrevFrame(WebPIterator* iter);
175
176// Releases any memory associated with 'iter'.
177// Must be called before any subsequent calls to WebPDemuxGetChunk() on the same
178// iter. Also, must be called before destroying the associated WebPDemuxer with
179// WebPDemuxDelete().
180WEBP_EXTERN void WebPDemuxReleaseIterator(WebPIterator* iter);
181
182//------------------------------------------------------------------------------
183// Chunk iteration.
184
185struct WebPChunkIterator {
186 // The current and total number of chunks with the fourcc given to
187 // WebPDemuxGetChunk().
188 int chunk_num;
189 int num_chunks;
190 WebPData chunk; // The payload of the chunk.
191
192 uint32_t pad[6]; // padding for later use
193 void* private_;
194};
195
196// Retrieves the 'chunk_number' instance of the chunk with id 'fourcc' from
197// 'dmux'.
198// 'fourcc' is a character array containing the fourcc of the chunk to return,
199// e.g., "ICCP", "XMP ", "EXIF", etc.
200// Setting 'chunk_number' equal to 0 will return the last chunk in a set.
201// Returns true if the chunk is found, false otherwise. Image related chunk
202// payloads are accessed through WebPDemuxGetFrame() and related functions.
203// Call WebPDemuxReleaseChunkIterator() when use of the iterator is complete.
204// NOTE: 'dmux' must persist for the lifetime of the iterator.
205WEBP_EXTERN int WebPDemuxGetChunk(const WebPDemuxer* dmux,
206 const char fourcc[4], int chunk_number,
207 WebPChunkIterator* iter);
208
209// Sets 'iter->chunk' to point to the next ('iter->chunk_num' + 1) or previous
210// ('iter->chunk_num' - 1) chunk. These functions do not loop.
211// Returns true on success, false otherwise.
212WEBP_EXTERN int WebPDemuxNextChunk(WebPChunkIterator* iter);
213WEBP_EXTERN int WebPDemuxPrevChunk(WebPChunkIterator* iter);
214
215// Releases any memory associated with 'iter'.
216// Must be called before destroying the associated WebPDemuxer with
217// WebPDemuxDelete().
218WEBP_EXTERN void WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter);
219
220//------------------------------------------------------------------------------
221// WebPAnimDecoder API
222//
223// This API allows decoding (possibly) animated WebP images.
224//
225// Code Example:
226/*
227 WebPAnimDecoderOptions dec_options;
228 WebPAnimDecoderOptionsInit(&dec_options);
229 // Tune 'dec_options' as needed.
230 WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options);
231 WebPAnimInfo anim_info;
232 WebPAnimDecoderGetInfo(dec, &anim_info);
233 for (uint32_t i = 0; i < anim_info.loop_count; ++i) {
234 while (WebPAnimDecoderHasMoreFrames(dec)) {
235 uint8_t* buf;
236 int timestamp;
237 WebPAnimDecoderGetNext(dec, &buf, &timestamp);
238 // ... (Render 'buf' based on 'timestamp').
239 // ... (Do NOT free 'buf', as it is owned by 'dec').
240 }
241 WebPAnimDecoderReset(dec);
242 }
243 const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec);
244 // ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data).
245 WebPAnimDecoderDelete(dec);
246*/
247
248typedef struct WebPAnimDecoder WebPAnimDecoder; // Main opaque object.
249
250// Global options.
251struct WebPAnimDecoderOptions {
252 // Output colorspace. Only the following modes are supported:
253 // MODE_RGBA, MODE_BGRA, MODE_rgbA and MODE_bgrA.
254 WEBP_CSP_MODE color_mode;
255 int use_threads; // If true, use multi-threaded decoding.
256 uint32_t padding[7]; // Padding for later use.
257};
258
259// Internal, version-checked, entry point.
260WEBP_EXTERN int WebPAnimDecoderOptionsInitInternal(
261 WebPAnimDecoderOptions*, int);
262
263// Should always be called, to initialize a fresh WebPAnimDecoderOptions
264// structure before modification. Returns false in case of version mismatch.
265// WebPAnimDecoderOptionsInit() must have succeeded before using the
266// 'dec_options' object.
267static WEBP_INLINE int WebPAnimDecoderOptionsInit(
268 WebPAnimDecoderOptions* dec_options) {
269 return WebPAnimDecoderOptionsInitInternal(dec_options,
270 WEBP_DEMUX_ABI_VERSION);
271}
272
273// Internal, version-checked, entry point.
274WEBP_EXTERN WebPAnimDecoder* WebPAnimDecoderNewInternal(
275 const WebPData*, const WebPAnimDecoderOptions*, int);
276
277// Creates and initializes a WebPAnimDecoder object.
278// Parameters:
279// webp_data - (in) WebP bitstream. This should remain unchanged during the
280// lifetime of the output WebPAnimDecoder object.
281// dec_options - (in) decoding options. Can be passed NULL to choose
282// reasonable defaults (in particular, color mode MODE_RGBA
283// will be picked).
284// Returns:
285// A pointer to the newly created WebPAnimDecoder object, or NULL in case of
286// parsing error, invalid option or memory error.
287static WEBP_INLINE WebPAnimDecoder* WebPAnimDecoderNew(
288 const WebPData* webp_data, const WebPAnimDecoderOptions* dec_options) {
289 return WebPAnimDecoderNewInternal(webp_data, dec_options,
290 WEBP_DEMUX_ABI_VERSION);
291}
292
293// Global information about the animation..
294struct WebPAnimInfo {
295 uint32_t canvas_width;
296 uint32_t canvas_height;
297 uint32_t loop_count;
298 uint32_t bgcolor;
299 uint32_t frame_count;
300 uint32_t pad[4]; // padding for later use
301};
302
303// Get global information about the animation.
304// Parameters:
305// dec - (in) decoder instance to get information from.
306// info - (out) global information fetched from the animation.
307// Returns:
308// True on success.
309WEBP_EXTERN int WebPAnimDecoderGetInfo(const WebPAnimDecoder* dec,
310 WebPAnimInfo* info);
311
312// Fetch the next frame from 'dec' based on options supplied to
313// WebPAnimDecoderNew(). This will be a fully reconstructed canvas of size
314// 'canvas_width * 4 * canvas_height', and not just the frame sub-rectangle. The
315// returned buffer 'buf' is valid only until the next call to
316// WebPAnimDecoderGetNext(), WebPAnimDecoderReset() or WebPAnimDecoderDelete().
317// Parameters:
318// dec - (in/out) decoder instance from which the next frame is to be fetched.
319// buf - (out) decoded frame.
320// timestamp - (out) timestamp of the frame in milliseconds.
321// Returns:
322// False if any of the arguments are NULL, or if there is a parsing or
323// decoding error, or if there are no more frames. Otherwise, returns true.
324WEBP_EXTERN int WebPAnimDecoderGetNext(WebPAnimDecoder* dec,
325 uint8_t** buf, int* timestamp);
326
327// Check if there are more frames left to decode.
328// Parameters:
329// dec - (in) decoder instance to be checked.
330// Returns:
331// True if 'dec' is not NULL and some frames are yet to be decoded.
332// Otherwise, returns false.
333WEBP_EXTERN int WebPAnimDecoderHasMoreFrames(const WebPAnimDecoder* dec);
334
335// Resets the WebPAnimDecoder object, so that next call to
336// WebPAnimDecoderGetNext() will restart decoding from 1st frame. This would be
337// helpful when all frames need to be decoded multiple times (e.g.
338// info.loop_count times) without destroying and recreating the 'dec' object.
339// Parameters:
340// dec - (in/out) decoder instance to be reset
341WEBP_EXTERN void WebPAnimDecoderReset(WebPAnimDecoder* dec);
342
343// Grab the internal demuxer object.
344// Getting the demuxer object can be useful if one wants to use operations only
345// available through demuxer; e.g. to get XMP/EXIF/ICC metadata. The returned
346// demuxer object is owned by 'dec' and is valid only until the next call to
347// WebPAnimDecoderDelete().
348//
349// Parameters:
350// dec - (in) decoder instance from which the demuxer object is to be fetched.
351WEBP_EXTERN const WebPDemuxer* WebPAnimDecoderGetDemuxer(
352 const WebPAnimDecoder* dec);
353
354// Deletes the WebPAnimDecoder object.
355// Parameters:
356// dec - (in/out) decoder instance to be deleted
357WEBP_EXTERN void WebPAnimDecoderDelete(WebPAnimDecoder* dec);
358
359#ifdef __cplusplus
360} // extern "C"
361#endif
362
363#endif /* WEBP_WEBP_DEMUX_H_ */
364