1 // Copyright 2011 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 // RIFF container manipulation and encoding for WebP images.
11 //
12 // Authors: Urvang (urvang@google.com)
13 // Vikas (vikasa@google.com)
14
15 #ifndef WEBP_WEBP_MUX_H_
16 #define WEBP_WEBP_MUX_H_
17
18 #include "./mux_types.h"
19
20 #ifdef __cplusplus
21 extern "C" {
22 #endif
23
24 #define WEBP_MUX_ABI_VERSION 0x0108 // MAJOR(8b) + MINOR(8b)
25
26 //------------------------------------------------------------------------------
27 // Mux API
28 //
29 // This API allows manipulation of WebP container images containing features
30 // like color profile, metadata, animation.
31 //
32 // Code Example#1: Create a WebPMux object with image data, color profile and
33 // XMP metadata.
34 /*
35 int copy_data = 0;
36 WebPMux* mux = WebPMuxNew();
37 // ... (Prepare image data).
38 WebPMuxSetImage(mux, &image, copy_data);
39 // ... (Prepare ICCP color profile data).
40 WebPMuxSetChunk(mux, "ICCP", &icc_profile, copy_data);
41 // ... (Prepare XMP metadata).
42 WebPMuxSetChunk(mux, "XMP ", &xmp, copy_data);
43 // Get data from mux in WebP RIFF format.
44 WebPMuxAssemble(mux, &output_data);
45 WebPMuxDelete(mux);
46 // ... (Consume output_data; e.g. write output_data.bytes to file).
47 WebPDataClear(&output_data);
48 */
49
50 // Code Example#2: Get image and color profile data from a WebP file.
51 /*
52 int copy_data = 0;
53 // ... (Read data from file).
54 WebPMux* mux = WebPMuxCreate(&data, copy_data);
55 WebPMuxGetFrame(mux, 1, &image);
56 // ... (Consume image; e.g. call WebPDecode() to decode the data).
57 WebPMuxGetChunk(mux, "ICCP", &icc_profile);
58 // ... (Consume icc_data).
59 WebPMuxDelete(mux);
60 free(data);
61 */
62
63 // Note: forward declaring enumerations is not allowed in (strict) C and C++,
64 // the types are left here for reference.
65 // typedef enum WebPMuxError WebPMuxError;
66 // typedef enum WebPChunkId WebPChunkId;
67 typedef struct WebPMux WebPMux; // main opaque object.
68 typedef struct WebPMuxFrameInfo WebPMuxFrameInfo;
69 typedef struct WebPMuxAnimParams WebPMuxAnimParams;
70 typedef struct WebPAnimEncoderOptions WebPAnimEncoderOptions;
71
72 // Error codes
73 typedef enum WebPMuxError {
74 WEBP_MUX_OK = 1,
75 WEBP_MUX_NOT_FOUND = 0,
76 WEBP_MUX_INVALID_ARGUMENT = -1,
77 WEBP_MUX_BAD_DATA = -2,
78 WEBP_MUX_MEMORY_ERROR = -3,
79 WEBP_MUX_NOT_ENOUGH_DATA = -4
80 } WebPMuxError;
81
82 // IDs for different types of chunks.
83 typedef enum WebPChunkId {
84 WEBP_CHUNK_VP8X, // VP8X
85 WEBP_CHUNK_ICCP, // ICCP
86 WEBP_CHUNK_ANIM, // ANIM
87 WEBP_CHUNK_ANMF, // ANMF
88 WEBP_CHUNK_DEPRECATED, // (deprecated from FRGM)
89 WEBP_CHUNK_ALPHA, // ALPH
90 WEBP_CHUNK_IMAGE, // VP8/VP8L
91 WEBP_CHUNK_EXIF, // EXIF
92 WEBP_CHUNK_XMP, // XMP
93 WEBP_CHUNK_UNKNOWN, // Other chunks.
94 WEBP_CHUNK_NIL
95 } WebPChunkId;
96
97 //------------------------------------------------------------------------------
98
99 // Returns the version number of the mux library, packed in hexadecimal using
100 // 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507.
101 WEBP_EXTERN int WebPGetMuxVersion(void);
102
103 //------------------------------------------------------------------------------
104 // Life of a Mux object
105
106 // Internal, version-checked, entry point
107 WEBP_EXTERN WebPMux* WebPNewInternal(int);
108
109 // Creates an empty mux object.
110 // Returns:
111 // A pointer to the newly created empty mux object.
112 // Or NULL in case of memory error.
WebPMuxNew(void)113 static WEBP_INLINE WebPMux* WebPMuxNew(void) {
114 return WebPNewInternal(WEBP_MUX_ABI_VERSION);
115 }
116
117 // Deletes the mux object.
118 // Parameters:
119 // mux - (in/out) object to be deleted
120 WEBP_EXTERN void WebPMuxDelete(WebPMux* mux);
121
122 //------------------------------------------------------------------------------
123 // Mux creation.
124
125 // Internal, version-checked, entry point
126 WEBP_EXTERN WebPMux* WebPMuxCreateInternal(const WebPData*, int, int);
127
128 // Creates a mux object from raw data given in WebP RIFF format.
129 // Parameters:
130 // bitstream - (in) the bitstream data in WebP RIFF format
131 // copy_data - (in) value 1 indicates given data WILL be copied to the mux
132 // object and value 0 indicates data will NOT be copied.
133 // Returns:
134 // A pointer to the mux object created from given data - on success.
135 // NULL - In case of invalid data or memory error.
WebPMuxCreate(const WebPData * bitstream,int copy_data)136 static WEBP_INLINE WebPMux* WebPMuxCreate(const WebPData* bitstream,
137 int copy_data) {
138 return WebPMuxCreateInternal(bitstream, copy_data, WEBP_MUX_ABI_VERSION);
139 }
140
141 //------------------------------------------------------------------------------
142 // Non-image chunks.
143
144 // Note: Only non-image related chunks should be managed through chunk APIs.
145 // (Image related chunks are: "ANMF", "VP8 ", "VP8L" and "ALPH").
146 // To add, get and delete images, use WebPMuxSetImage(), WebPMuxPushFrame(),
147 // WebPMuxGetFrame() and WebPMuxDeleteFrame().
148
149 // Adds a chunk with id 'fourcc' and data 'chunk_data' in the mux object.
150 // Any existing chunk(s) with the same id will be removed.
151 // Parameters:
152 // mux - (in/out) object to which the chunk is to be added
153 // fourcc - (in) a character array containing the fourcc of the given chunk;
154 // e.g., "ICCP", "XMP ", "EXIF" etc.
155 // chunk_data - (in) the chunk data to be added
156 // copy_data - (in) value 1 indicates given data WILL be copied to the mux
157 // object and value 0 indicates data will NOT be copied.
158 // Returns:
159 // WEBP_MUX_INVALID_ARGUMENT - if mux, fourcc or chunk_data is NULL
160 // or if fourcc corresponds to an image chunk.
161 // WEBP_MUX_MEMORY_ERROR - on memory allocation error.
162 // WEBP_MUX_OK - on success.
163 WEBP_EXTERN WebPMuxError WebPMuxSetChunk(
164 WebPMux* mux, const char fourcc[4], const WebPData* chunk_data,
165 int copy_data);
166
167 // Gets a reference to the data of the chunk with id 'fourcc' in the mux object.
168 // The caller should NOT free the returned data.
169 // Parameters:
170 // mux - (in) object from which the chunk data is to be fetched
171 // fourcc - (in) a character array containing the fourcc of the chunk;
172 // e.g., "ICCP", "XMP ", "EXIF" etc.
173 // chunk_data - (out) returned chunk data
174 // Returns:
175 // WEBP_MUX_INVALID_ARGUMENT - if mux, fourcc or chunk_data is NULL
176 // or if fourcc corresponds to an image chunk.
177 // WEBP_MUX_NOT_FOUND - If mux does not contain a chunk with the given id.
178 // WEBP_MUX_OK - on success.
179 WEBP_EXTERN WebPMuxError WebPMuxGetChunk(
180 const WebPMux* mux, const char fourcc[4], WebPData* chunk_data);
181
182 // Deletes the chunk with the given 'fourcc' from the mux object.
183 // Parameters:
184 // mux - (in/out) object from which the chunk is to be deleted
185 // fourcc - (in) a character array containing the fourcc of the chunk;
186 // e.g., "ICCP", "XMP ", "EXIF" etc.
187 // Returns:
188 // WEBP_MUX_INVALID_ARGUMENT - if mux or fourcc is NULL
189 // or if fourcc corresponds to an image chunk.
190 // WEBP_MUX_NOT_FOUND - If mux does not contain a chunk with the given fourcc.
191 // WEBP_MUX_OK - on success.
192 WEBP_EXTERN WebPMuxError WebPMuxDeleteChunk(
193 WebPMux* mux, const char fourcc[4]);
194
195 //------------------------------------------------------------------------------
196 // Images.
197
198 // Encapsulates data about a single frame.
199 struct WebPMuxFrameInfo {
200 WebPData bitstream; // image data: can be a raw VP8/VP8L bitstream
201 // or a single-image WebP file.
202 int x_offset; // x-offset of the frame.
203 int y_offset; // y-offset of the frame.
204 int duration; // duration of the frame (in milliseconds).
205
206 WebPChunkId id; // frame type: should be one of WEBP_CHUNK_ANMF
207 // or WEBP_CHUNK_IMAGE
208 WebPMuxAnimDispose dispose_method; // Disposal method for the frame.
209 WebPMuxAnimBlend blend_method; // Blend operation for the frame.
210 uint32_t pad[1]; // padding for later use
211 };
212
213 // Sets the (non-animated) image in the mux object.
214 // Note: Any existing images (including frames) will be removed.
215 // Parameters:
216 // mux - (in/out) object in which the image is to be set
217 // bitstream - (in) can be a raw VP8/VP8L bitstream or a single-image
218 // WebP file (non-animated)
219 // copy_data - (in) value 1 indicates given data WILL be copied to the mux
220 // object and value 0 indicates data will NOT be copied.
221 // Returns:
222 // WEBP_MUX_INVALID_ARGUMENT - if mux is NULL or bitstream is NULL.
223 // WEBP_MUX_MEMORY_ERROR - on memory allocation error.
224 // WEBP_MUX_OK - on success.
225 WEBP_EXTERN WebPMuxError WebPMuxSetImage(
226 WebPMux* mux, const WebPData* bitstream, int copy_data);
227
228 // Adds a frame at the end of the mux object.
229 // Notes: (1) frame.id should be WEBP_CHUNK_ANMF
230 // (2) For setting a non-animated image, use WebPMuxSetImage() instead.
231 // (3) Type of frame being pushed must be same as the frames in mux.
232 // (4) As WebP only supports even offsets, any odd offset will be snapped
233 // to an even location using: offset &= ~1
234 // Parameters:
235 // mux - (in/out) object to which the frame is to be added
236 // frame - (in) frame data.
237 // copy_data - (in) value 1 indicates given data WILL be copied to the mux
238 // object and value 0 indicates data will NOT be copied.
239 // Returns:
240 // WEBP_MUX_INVALID_ARGUMENT - if mux or frame is NULL
241 // or if content of 'frame' is invalid.
242 // WEBP_MUX_MEMORY_ERROR - on memory allocation error.
243 // WEBP_MUX_OK - on success.
244 WEBP_EXTERN WebPMuxError WebPMuxPushFrame(
245 WebPMux* mux, const WebPMuxFrameInfo* frame, int copy_data);
246
247 // Gets the nth frame from the mux object.
248 // The content of 'frame->bitstream' is allocated using malloc(), and NOT
249 // owned by the 'mux' object. It MUST be deallocated by the caller by calling
250 // WebPDataClear().
251 // nth=0 has a special meaning - last position.
252 // Parameters:
253 // mux - (in) object from which the info is to be fetched
254 // nth - (in) index of the frame in the mux object
255 // frame - (out) data of the returned frame
256 // Returns:
257 // WEBP_MUX_INVALID_ARGUMENT - if mux or frame is NULL.
258 // WEBP_MUX_NOT_FOUND - if there are less than nth frames in the mux object.
259 // WEBP_MUX_BAD_DATA - if nth frame chunk in mux is invalid.
260 // WEBP_MUX_MEMORY_ERROR - on memory allocation error.
261 // WEBP_MUX_OK - on success.
262 WEBP_EXTERN WebPMuxError WebPMuxGetFrame(
263 const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* frame);
264
265 // Deletes a frame from the mux object.
266 // nth=0 has a special meaning - last position.
267 // Parameters:
268 // mux - (in/out) object from which a frame is to be deleted
269 // nth - (in) The position from which the frame is to be deleted
270 // Returns:
271 // WEBP_MUX_INVALID_ARGUMENT - if mux is NULL.
272 // WEBP_MUX_NOT_FOUND - If there are less than nth frames in the mux object
273 // before deletion.
274 // WEBP_MUX_OK - on success.
275 WEBP_EXTERN WebPMuxError WebPMuxDeleteFrame(WebPMux* mux, uint32_t nth);
276
277 //------------------------------------------------------------------------------
278 // Animation.
279
280 // Animation parameters.
281 struct WebPMuxAnimParams {
282 uint32_t bgcolor; // Background color of the canvas stored (in MSB order) as:
283 // Bits 00 to 07: Alpha.
284 // Bits 08 to 15: Red.
285 // Bits 16 to 23: Green.
286 // Bits 24 to 31: Blue.
287 int loop_count; // Number of times to repeat the animation [0 = infinite].
288 };
289
290 // Sets the animation parameters in the mux object. Any existing ANIM chunks
291 // will be removed.
292 // Parameters:
293 // mux - (in/out) object in which ANIM chunk is to be set/added
294 // params - (in) animation parameters.
295 // Returns:
296 // WEBP_MUX_INVALID_ARGUMENT - if mux or params is NULL.
297 // WEBP_MUX_MEMORY_ERROR - on memory allocation error.
298 // WEBP_MUX_OK - on success.
299 WEBP_EXTERN WebPMuxError WebPMuxSetAnimationParams(
300 WebPMux* mux, const WebPMuxAnimParams* params);
301
302 // Gets the animation parameters from the mux object.
303 // Parameters:
304 // mux - (in) object from which the animation parameters to be fetched
305 // params - (out) animation parameters extracted from the ANIM chunk
306 // Returns:
307 // WEBP_MUX_INVALID_ARGUMENT - if mux or params is NULL.
308 // WEBP_MUX_NOT_FOUND - if ANIM chunk is not present in mux object.
309 // WEBP_MUX_OK - on success.
310 WEBP_EXTERN WebPMuxError WebPMuxGetAnimationParams(
311 const WebPMux* mux, WebPMuxAnimParams* params);
312
313 //------------------------------------------------------------------------------
314 // Misc Utilities.
315
316 // Sets the canvas size for the mux object. The width and height can be
317 // specified explicitly or left as zero (0, 0).
318 // * When width and height are specified explicitly, then this frame bound is
319 // enforced during subsequent calls to WebPMuxAssemble() and an error is
320 // reported if any animated frame does not completely fit within the canvas.
321 // * When unspecified (0, 0), the constructed canvas will get the frame bounds
322 // from the bounding-box over all frames after calling WebPMuxAssemble().
323 // Parameters:
324 // mux - (in) object to which the canvas size is to be set
325 // width - (in) canvas width
326 // height - (in) canvas height
327 // Returns:
328 // WEBP_MUX_INVALID_ARGUMENT - if mux is NULL; or
329 // width or height are invalid or out of bounds
330 // WEBP_MUX_OK - on success.
331 WEBP_EXTERN WebPMuxError WebPMuxSetCanvasSize(WebPMux* mux,
332 int width, int height);
333
334 // Gets the canvas size from the mux object.
335 // Note: This method assumes that the VP8X chunk, if present, is up-to-date.
336 // That is, the mux object hasn't been modified since the last call to
337 // WebPMuxAssemble() or WebPMuxCreate().
338 // Parameters:
339 // mux - (in) object from which the canvas size is to be fetched
340 // width - (out) canvas width
341 // height - (out) canvas height
342 // Returns:
343 // WEBP_MUX_INVALID_ARGUMENT - if mux, width or height is NULL.
344 // WEBP_MUX_BAD_DATA - if VP8X/VP8/VP8L chunk or canvas size is invalid.
345 // WEBP_MUX_OK - on success.
346 WEBP_EXTERN WebPMuxError WebPMuxGetCanvasSize(const WebPMux* mux,
347 int* width, int* height);
348
349 // Gets the feature flags from the mux object.
350 // Note: This method assumes that the VP8X chunk, if present, is up-to-date.
351 // That is, the mux object hasn't been modified since the last call to
352 // WebPMuxAssemble() or WebPMuxCreate().
353 // Parameters:
354 // mux - (in) object from which the features are to be fetched
355 // flags - (out) the flags specifying which features are present in the
356 // mux object. This will be an OR of various flag values.
357 // Enum 'WebPFeatureFlags' can be used to test individual flag values.
358 // Returns:
359 // WEBP_MUX_INVALID_ARGUMENT - if mux or flags is NULL.
360 // WEBP_MUX_BAD_DATA - if VP8X/VP8/VP8L chunk or canvas size is invalid.
361 // WEBP_MUX_OK - on success.
362 WEBP_EXTERN WebPMuxError WebPMuxGetFeatures(const WebPMux* mux,
363 uint32_t* flags);
364
365 // Gets number of chunks with the given 'id' in the mux object.
366 // Parameters:
367 // mux - (in) object from which the info is to be fetched
368 // id - (in) chunk id specifying the type of chunk
369 // num_elements - (out) number of chunks with the given chunk id
370 // Returns:
371 // WEBP_MUX_INVALID_ARGUMENT - if mux, or num_elements is NULL.
372 // WEBP_MUX_OK - on success.
373 WEBP_EXTERN WebPMuxError WebPMuxNumChunks(const WebPMux* mux,
374 WebPChunkId id, int* num_elements);
375
376 // Assembles all chunks in WebP RIFF format and returns in 'assembled_data'.
377 // This function also validates the mux object.
378 // Note: The content of 'assembled_data' will be ignored and overwritten.
379 // Also, the content of 'assembled_data' is allocated using malloc(), and NOT
380 // owned by the 'mux' object. It MUST be deallocated by the caller by calling
381 // WebPDataClear(). It's always safe to call WebPDataClear() upon return,
382 // even in case of error.
383 // Parameters:
384 // mux - (in/out) object whose chunks are to be assembled
385 // assembled_data - (out) assembled WebP data
386 // Returns:
387 // WEBP_MUX_BAD_DATA - if mux object is invalid.
388 // WEBP_MUX_INVALID_ARGUMENT - if mux or assembled_data is NULL.
389 // WEBP_MUX_MEMORY_ERROR - on memory allocation error.
390 // WEBP_MUX_OK - on success.
391 WEBP_EXTERN WebPMuxError WebPMuxAssemble(WebPMux* mux,
392 WebPData* assembled_data);
393
394 //------------------------------------------------------------------------------
395 // WebPAnimEncoder API
396 //
397 // This API allows encoding (possibly) animated WebP images.
398 //
399 // Code Example:
400 /*
401 WebPAnimEncoderOptions enc_options;
402 WebPAnimEncoderOptionsInit(&enc_options);
403 // Tune 'enc_options' as needed.
404 WebPAnimEncoder* enc = WebPAnimEncoderNew(width, height, &enc_options);
405 while(<there are more frames>) {
406 WebPConfig config;
407 WebPConfigInit(&config);
408 // Tune 'config' as needed.
409 WebPAnimEncoderAdd(enc, frame, timestamp_ms, &config);
410 }
411 WebPAnimEncoderAdd(enc, NULL, timestamp_ms, NULL);
412 WebPAnimEncoderAssemble(enc, webp_data);
413 WebPAnimEncoderDelete(enc);
414 // Write the 'webp_data' to a file, or re-mux it further.
415 */
416
417 typedef struct WebPAnimEncoder WebPAnimEncoder; // Main opaque object.
418
419 // Forward declarations. Defined in encode.h.
420 struct WebPPicture;
421 struct WebPConfig;
422
423 // Global options.
424 struct WebPAnimEncoderOptions {
425 WebPMuxAnimParams anim_params; // Animation parameters.
426 int minimize_size; // If true, minimize the output size (slow). Implicitly
427 // disables key-frame insertion.
428 int kmin;
429 int kmax; // Minimum and maximum distance between consecutive key
430 // frames in the output. The library may insert some key
431 // frames as needed to satisfy this criteria.
432 // Note that these conditions should hold: kmax > kmin
433 // and kmin >= kmax / 2 + 1. Also, if kmax <= 0, then
434 // key-frame insertion is disabled; and if kmax == 1,
435 // then all frames will be key-frames (kmin value does
436 // not matter for these special cases).
437 int allow_mixed; // If true, use mixed compression mode; may choose
438 // either lossy and lossless for each frame.
439 int verbose; // If true, print info and warning messages to stderr.
440
441 uint32_t padding[4]; // Padding for later use.
442 };
443
444 // Internal, version-checked, entry point.
445 WEBP_EXTERN int WebPAnimEncoderOptionsInitInternal(
446 WebPAnimEncoderOptions*, int);
447
448 // Should always be called, to initialize a fresh WebPAnimEncoderOptions
449 // structure before modification. Returns false in case of version mismatch.
450 // WebPAnimEncoderOptionsInit() must have succeeded before using the
451 // 'enc_options' object.
WebPAnimEncoderOptionsInit(WebPAnimEncoderOptions * enc_options)452 static WEBP_INLINE int WebPAnimEncoderOptionsInit(
453 WebPAnimEncoderOptions* enc_options) {
454 return WebPAnimEncoderOptionsInitInternal(enc_options, WEBP_MUX_ABI_VERSION);
455 }
456
457 // Internal, version-checked, entry point.
458 WEBP_EXTERN WebPAnimEncoder* WebPAnimEncoderNewInternal(
459 int, int, const WebPAnimEncoderOptions*, int);
460
461 // Creates and initializes a WebPAnimEncoder object.
462 // Parameters:
463 // width/height - (in) canvas width and height of the animation.
464 // enc_options - (in) encoding options; can be passed NULL to pick
465 // reasonable defaults.
466 // Returns:
467 // A pointer to the newly created WebPAnimEncoder object.
468 // Or NULL in case of memory error.
WebPAnimEncoderNew(int width,int height,const WebPAnimEncoderOptions * enc_options)469 static WEBP_INLINE WebPAnimEncoder* WebPAnimEncoderNew(
470 int width, int height, const WebPAnimEncoderOptions* enc_options) {
471 return WebPAnimEncoderNewInternal(width, height, enc_options,
472 WEBP_MUX_ABI_VERSION);
473 }
474
475 // Optimize the given frame for WebP, encode it and add it to the
476 // WebPAnimEncoder object.
477 // The last call to 'WebPAnimEncoderAdd' should be with frame = NULL, which
478 // indicates that no more frames are to be added. This call is also used to
479 // determine the duration of the last frame.
480 // Parameters:
481 // enc - (in/out) object to which the frame is to be added.
482 // frame - (in/out) frame data in ARGB or YUV(A) format. If it is in YUV(A)
483 // format, it will be converted to ARGB, which incurs a small loss.
484 // timestamp_ms - (in) timestamp of this frame in milliseconds.
485 // Duration of a frame would be calculated as
486 // "timestamp of next frame - timestamp of this frame".
487 // Hence, timestamps should be in non-decreasing order.
488 // config - (in) encoding options; can be passed NULL to pick
489 // reasonable defaults.
490 // Returns:
491 // On error, returns false and frame->error_code is set appropriately.
492 // Otherwise, returns true.
493 WEBP_EXTERN int WebPAnimEncoderAdd(
494 WebPAnimEncoder* enc, struct WebPPicture* frame, int timestamp_ms,
495 const struct WebPConfig* config);
496
497 // Assemble all frames added so far into a WebP bitstream.
498 // This call should be preceded by a call to 'WebPAnimEncoderAdd' with
499 // frame = NULL; if not, the duration of the last frame will be internally
500 // estimated.
501 // Parameters:
502 // enc - (in/out) object from which the frames are to be assembled.
503 // webp_data - (out) generated WebP bitstream.
504 // Returns:
505 // True on success.
506 WEBP_EXTERN int WebPAnimEncoderAssemble(WebPAnimEncoder* enc,
507 WebPData* webp_data);
508
509 // Get error string corresponding to the most recent call using 'enc'. The
510 // returned string is owned by 'enc' and is valid only until the next call to
511 // WebPAnimEncoderAdd() or WebPAnimEncoderAssemble() or WebPAnimEncoderDelete().
512 // Parameters:
513 // enc - (in/out) object from which the error string is to be fetched.
514 // Returns:
515 // NULL if 'enc' is NULL. Otherwise, returns the error string if the last call
516 // to 'enc' had an error, or an empty string if the last call was a success.
517 WEBP_EXTERN const char* WebPAnimEncoderGetError(WebPAnimEncoder* enc);
518
519 // Deletes the WebPAnimEncoder object.
520 // Parameters:
521 // enc - (in/out) object to be deleted
522 WEBP_EXTERN void WebPAnimEncoderDelete(WebPAnimEncoder* enc);
523
524 //------------------------------------------------------------------------------
525
526 #ifdef __cplusplus
527 } // extern "C"
528 #endif
529
530 #endif // WEBP_WEBP_MUX_H_
531