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#include "./types.h"
54
55#ifdef __cplusplus
56extern "C" {
57#endif
58
59#define WEBP_DEMUX_ABI_VERSION 0x0107 // MAJOR(8b) + MINOR(8b)
60
61// Note: forward declaring enumerations is not allowed in (strict) C and C++,
62// the types are left here for reference.
63// typedef enum WebPDemuxState WebPDemuxState;
64// typedef enum WebPFormatFeature WebPFormatFeature;
65typedef struct WebPDemuxer WebPDemuxer;
66typedef struct WebPIterator WebPIterator;
67typedef struct WebPChunkIterator WebPChunkIterator;
68typedef struct WebPAnimInfo WebPAnimInfo;
69typedef struct WebPAnimDecoderOptions WebPAnimDecoderOptions;
70
71//------------------------------------------------------------------------------
72
73// Returns the version number of the demux library, packed in hexadecimal using
74// 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507.
75WEBP_EXTERN int WebPGetDemuxVersion(void);
76
77//------------------------------------------------------------------------------
78// Life of a Demux object
79
80typedef enum WebPDemuxState {
81 WEBP_DEMUX_PARSE_ERROR = -1, // An error occurred while parsing.
82 WEBP_DEMUX_PARSING_HEADER = 0, // Not enough data to parse full header.
83 WEBP_DEMUX_PARSED_HEADER = 1, // Header parsing complete,
84 // data may be available.
85 WEBP_DEMUX_DONE = 2 // Entire file has been parsed.
86} WebPDemuxState;
87
88// Internal, version-checked, entry point
89WEBP_NODISCARD WEBP_EXTERN WebPDemuxer* WebPDemuxInternal(
90 const WebPData*, int, WebPDemuxState*, int);
91
92// Parses the full WebP file given by 'data'. For single images the WebP file
93// header alone or the file header and the chunk header may be absent.
94// Returns a WebPDemuxer object on successful parse, NULL otherwise.
95WEBP_NODISCARD static WEBP_INLINE WebPDemuxer* WebPDemux(const WebPData* data) {
96 return WebPDemuxInternal(data, 0, NULL, WEBP_DEMUX_ABI_VERSION);
97}
98
99// Parses the possibly incomplete WebP file given by 'data'.
100// If 'state' is non-NULL it will be set to indicate the status of the demuxer.
101// Returns NULL in case of error or if there isn't enough data to start parsing;
102// and a WebPDemuxer object on successful parse.
103// Note that WebPDemuxer keeps internal pointers to 'data' memory segment.
104// If this data is volatile, the demuxer object should be deleted (by calling
105// WebPDemuxDelete()) and WebPDemuxPartial() called again on the new data.
106// This is usually an inexpensive operation.
107WEBP_NODISCARD static WEBP_INLINE WebPDemuxer* WebPDemuxPartial(
108 const WebPData* data, WebPDemuxState* state) {
109 return WebPDemuxInternal(data, 1, state, WEBP_DEMUX_ABI_VERSION);
110}
111
112// Frees memory associated with 'dmux'.
113WEBP_EXTERN void WebPDemuxDelete(WebPDemuxer* dmux);
114
115//------------------------------------------------------------------------------
116// Data/information extraction.
117
118typedef enum WebPFormatFeature {
119 WEBP_FF_FORMAT_FLAGS, // bit-wise combination of WebPFeatureFlags
120 // corresponding to the 'VP8X' chunk (if present).
121 WEBP_FF_CANVAS_WIDTH,
122 WEBP_FF_CANVAS_HEIGHT,
123 WEBP_FF_LOOP_COUNT, // only relevant for animated file
124 WEBP_FF_BACKGROUND_COLOR, // idem.
125 WEBP_FF_FRAME_COUNT // Number of frames present in the demux object.
126 // In case of a partial demux, this is the number
127 // of frames seen so far, with the last frame
128 // possibly being partial.
129} WebPFormatFeature;
130
131// Get the 'feature' value from the 'dmux'.
132// NOTE: values are only valid if WebPDemux() was used or WebPDemuxPartial()
133// returned a state > WEBP_DEMUX_PARSING_HEADER.
134// If 'feature' is WEBP_FF_FORMAT_FLAGS, the returned value is a bit-wise
135// combination of WebPFeatureFlags values.
136// If 'feature' is WEBP_FF_LOOP_COUNT, WEBP_FF_BACKGROUND_COLOR, the returned
137// value is only meaningful if the bitstream is animated.
138WEBP_EXTERN uint32_t WebPDemuxGetI(
139 const WebPDemuxer* dmux, WebPFormatFeature feature);
140
141//------------------------------------------------------------------------------
142// Frame iteration.
143
144struct WebPIterator {
145 int frame_num;
146 int num_frames; // equivalent to WEBP_FF_FRAME_COUNT.
147 int x_offset, y_offset; // offset relative to the canvas.
148 int width, height; // dimensions of this frame.
149 int duration; // display duration in milliseconds.
150 WebPMuxAnimDispose dispose_method; // dispose method for the frame.
151 int complete; // true if 'fragment' contains a full frame. partial images
152 // may still be decoded with the WebP incremental decoder.
153 WebPData fragment; // The frame given by 'frame_num'. Note for historical
154 // reasons this is called a fragment.
155 int has_alpha; // True if the frame contains transparency.
156 WebPMuxAnimBlend blend_method; // Blend operation for the frame.
157
158 uint32_t pad[2]; // padding for later use.
159 void* private_; // for internal use only.
160};
161
162// Retrieves frame 'frame_number' from 'dmux'.
163// 'iter->fragment' points to the frame on return from this function.
164// Setting 'frame_number' equal to 0 will return the last frame of the image.
165// Returns false if 'dmux' is NULL or frame 'frame_number' is not present.
166// Call WebPDemuxReleaseIterator() when use of the iterator is complete.
167// NOTE: 'dmux' must persist for the lifetime of 'iter'.
168WEBP_NODISCARD WEBP_EXTERN int WebPDemuxGetFrame(
169 const WebPDemuxer* dmux, int frame_number, WebPIterator* iter);
170
171// Sets 'iter->fragment' to point to the next ('iter->frame_num' + 1) or
172// previous ('iter->frame_num' - 1) frame. These functions do not loop.
173// Returns true on success, false otherwise.
174WEBP_NODISCARD WEBP_EXTERN int WebPDemuxNextFrame(WebPIterator* iter);
175WEBP_NODISCARD WEBP_EXTERN int WebPDemuxPrevFrame(WebPIterator* iter);
176
177// Releases any memory associated with 'iter'.
178// Must be called before any subsequent calls to WebPDemuxGetChunk() on the same
179// iter. Also, must be called before destroying the associated WebPDemuxer with
180// WebPDemuxDelete().
181WEBP_EXTERN void WebPDemuxReleaseIterator(WebPIterator* iter);
182
183//------------------------------------------------------------------------------
184// Chunk iteration.
185
186struct WebPChunkIterator {
187 // The current and total number of chunks with the fourcc given to
188 // WebPDemuxGetChunk().
189 int chunk_num;
190 int num_chunks;
191 WebPData chunk; // The payload of the chunk.
192
193 uint32_t pad[6]; // padding for later use
194 void* private_;
195};
196
197// Retrieves the 'chunk_number' instance of the chunk with id 'fourcc' from
198// 'dmux'.
199// 'fourcc' is a character array containing the fourcc of the chunk to return,
200// e.g., "ICCP", "XMP ", "EXIF", etc.
201// Setting 'chunk_number' equal to 0 will return the last chunk in a set.
202// Returns true if the chunk is found, false otherwise. Image related chunk
203// payloads are accessed through WebPDemuxGetFrame() and related functions.
204// Call WebPDemuxReleaseChunkIterator() when use of the iterator is complete.
205// NOTE: 'dmux' must persist for the lifetime of the iterator.
206WEBP_NODISCARD WEBP_EXTERN int WebPDemuxGetChunk(const WebPDemuxer* dmux,
207 const char fourcc[4],
208 int chunk_number,
209 WebPChunkIterator* iter);
210
211// Sets 'iter->chunk' to point to the next ('iter->chunk_num' + 1) or previous
212// ('iter->chunk_num' - 1) chunk. These functions do not loop.
213// Returns true on success, false otherwise.
214WEBP_NODISCARD WEBP_EXTERN int WebPDemuxNextChunk(WebPChunkIterator* iter);
215WEBP_NODISCARD WEBP_EXTERN int WebPDemuxPrevChunk(WebPChunkIterator* iter);
216
217// Releases any memory associated with 'iter'.
218// Must be called before destroying the associated WebPDemuxer with
219// WebPDemuxDelete().
220WEBP_EXTERN void WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter);
221
222//------------------------------------------------------------------------------
223// WebPAnimDecoder API
224//
225// This API allows decoding (possibly) animated WebP images.
226//
227// Code Example:
228/*
229 WebPAnimDecoderOptions dec_options;
230 WebPAnimDecoderOptionsInit(&dec_options);
231 // Tune 'dec_options' as needed.
232 WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options);
233 WebPAnimInfo anim_info;
234 WebPAnimDecoderGetInfo(dec, &anim_info);
235 for (uint32_t i = 0; i < anim_info.loop_count; ++i) {
236 while (WebPAnimDecoderHasMoreFrames(dec)) {
237 uint8_t* buf;
238 int timestamp;
239 WebPAnimDecoderGetNext(dec, &buf, &timestamp);
240 // ... (Render 'buf' based on 'timestamp').
241 // ... (Do NOT free 'buf', as it is owned by 'dec').
242 }
243 WebPAnimDecoderReset(dec);
244 }
245 const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec);
246 // ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data).
247 WebPAnimDecoderDelete(dec);
248*/
249
250typedef struct WebPAnimDecoder WebPAnimDecoder; // Main opaque object.
251
252// Global options.
253struct WebPAnimDecoderOptions {
254 // Output colorspace. Only the following modes are supported:
255 // MODE_RGBA, MODE_BGRA, MODE_rgbA and MODE_bgrA.
256 WEBP_CSP_MODE color_mode;
257 int use_threads; // If true, use multi-threaded decoding.
258 uint32_t padding[7]; // Padding for later use.
259};
260
261// Internal, version-checked, entry point.
262WEBP_NODISCARD WEBP_EXTERN int WebPAnimDecoderOptionsInitInternal(
263 WebPAnimDecoderOptions*, int);
264
265// Should always be called, to initialize a fresh WebPAnimDecoderOptions
266// structure before modification. Returns false in case of version mismatch.
267// WebPAnimDecoderOptionsInit() must have succeeded before using the
268// 'dec_options' object.
269WEBP_NODISCARD static WEBP_INLINE int WebPAnimDecoderOptionsInit(
270 WebPAnimDecoderOptions* dec_options) {
271 return WebPAnimDecoderOptionsInitInternal(dec_options,
272 WEBP_DEMUX_ABI_VERSION);
273}
274
275// Internal, version-checked, entry point.
276WEBP_NODISCARD WEBP_EXTERN WebPAnimDecoder* WebPAnimDecoderNewInternal(
277 const WebPData*, const WebPAnimDecoderOptions*, int);
278
279// Creates and initializes a WebPAnimDecoder object.
280// Parameters:
281// webp_data - (in) WebP bitstream. This should remain unchanged during the
282// lifetime of the output WebPAnimDecoder object.
283// dec_options - (in) decoding options. Can be passed NULL to choose
284// reasonable defaults (in particular, color mode MODE_RGBA
285// will be picked).
286// Returns:
287// A pointer to the newly created WebPAnimDecoder object, or NULL in case of
288// parsing error, invalid option or memory error.
289WEBP_NODISCARD static WEBP_INLINE WebPAnimDecoder* WebPAnimDecoderNew(
290 const WebPData* webp_data, const WebPAnimDecoderOptions* dec_options) {
291 return WebPAnimDecoderNewInternal(webp_data, dec_options,
292 WEBP_DEMUX_ABI_VERSION);
293}
294
295// Global information about the animation..
296struct WebPAnimInfo {
297 uint32_t canvas_width;
298 uint32_t canvas_height;
299 uint32_t loop_count;
300 uint32_t bgcolor;
301 uint32_t frame_count;
302 uint32_t pad[4]; // padding for later use
303};
304
305// Get global information about the animation.
306// Parameters:
307// dec - (in) decoder instance to get information from.
308// info - (out) global information fetched from the animation.
309// Returns:
310// True on success.
311WEBP_NODISCARD WEBP_EXTERN int WebPAnimDecoderGetInfo(
312 const WebPAnimDecoder* dec, WebPAnimInfo* info);
313
314// Fetch the next frame from 'dec' based on options supplied to
315// WebPAnimDecoderNew(). This will be a fully reconstructed canvas of size
316// 'canvas_width * 4 * canvas_height', and not just the frame sub-rectangle. The
317// returned buffer 'buf' is valid only until the next call to
318// WebPAnimDecoderGetNext(), WebPAnimDecoderReset() or WebPAnimDecoderDelete().
319// Parameters:
320// dec - (in/out) decoder instance from which the next frame is to be fetched.
321// buf - (out) decoded frame.
322// timestamp - (out) timestamp of the frame in milliseconds.
323// Returns:
324// False if any of the arguments are NULL, or if there is a parsing or
325// decoding error, or if there are no more frames. Otherwise, returns true.
326WEBP_NODISCARD WEBP_EXTERN int WebPAnimDecoderGetNext(WebPAnimDecoder* dec,
327 uint8_t** buf,
328 int* timestamp);
329
330// Check if there are more frames left to decode.
331// Parameters:
332// dec - (in) decoder instance to be checked.
333// Returns:
334// True if 'dec' is not NULL and some frames are yet to be decoded.
335// Otherwise, returns false.
336WEBP_NODISCARD WEBP_EXTERN int WebPAnimDecoderHasMoreFrames(
337 const WebPAnimDecoder* dec);
338
339// Resets the WebPAnimDecoder object, so that next call to
340// WebPAnimDecoderGetNext() will restart decoding from 1st frame. This would be
341// helpful when all frames need to be decoded multiple times (e.g.
342// info.loop_count times) without destroying and recreating the 'dec' object.
343// Parameters:
344// dec - (in/out) decoder instance to be reset
345WEBP_EXTERN void WebPAnimDecoderReset(WebPAnimDecoder* dec);
346
347// Grab the internal demuxer object.
348// Getting the demuxer object can be useful if one wants to use operations only
349// available through demuxer; e.g. to get XMP/EXIF/ICC metadata. The returned
350// demuxer object is owned by 'dec' and is valid only until the next call to
351// WebPAnimDecoderDelete().
352//
353// Parameters:
354// dec - (in) decoder instance from which the demuxer object is to be fetched.
355WEBP_NODISCARD WEBP_EXTERN const WebPDemuxer* WebPAnimDecoderGetDemuxer(
356 const WebPAnimDecoder* dec);
357
358// Deletes the WebPAnimDecoder object.
359// Parameters:
360// dec - (in/out) decoder instance to be deleted
361WEBP_EXTERN void WebPAnimDecoderDelete(WebPAnimDecoder* dec);
362
363#ifdef __cplusplus
364} // extern "C"
365#endif
366
367#endif // WEBP_WEBP_DEMUX_H_
368

source code of qtimageformats/src/3rdparty/libwebp/src/webp/demux.h