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[libav.git] / libavfilter / avfilter.h
1 /*
2 * filter layer
3 * copyright (c) 2007 Bobby Bingham
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #ifndef FFMPEG_AVFILTER_H
23 #define FFMPEG_AVFILTER_H
24
25 #define LIBAVFILTER_VERSION 0.0.0
26
27 #include <stddef.h>
28 #include "avcodec.h"
29
30 typedef struct AVFilterContext AVFilterContext;
31 typedef struct AVFilterLink AVFilterLink;
32 typedef struct AVFilterPad AVFilterPad;
33
34 /* TODO: look for other flags which may be useful in this structure (interlace
35 * flags, etc)
36 */
37 /**
38 * A reference-counted picture data type used by the filter system. Filters
39 * should not store pointers to this structure directly, but instead use the
40 * AVFilterPicRef structure below.
41 */
42 typedef struct AVFilterPic
43 {
44 uint8_t *data[4]; ///< picture data for each plane
45 int linesize[4]; ///< number of bytes per line
46 enum PixelFormat format; ///< colorspace
47
48 unsigned refcount; ///< number of references to this image
49
50 /** private data to be used by a custom free function */
51 void *priv;
52 /**
53 * A pointer to the function to deallocate this image if the default
54 * function is not sufficient. This could, for example, add the memory
55 * back into a memory pool to be reused later without the overhead of
56 * reallocating it from scratch.
57 */
58 void (*free)(struct AVFilterPic *pic);
59 } AVFilterPic;
60
61 /**
62 * A reference to an AVFilterPic. Since filters can manipulate the origin of
63 * a picture to, for example, crop image without any memcpy, the picture origin
64 * and dimensions are per-reference properties. Linesize is also useful for
65 * image flipping, frame to field filters, etc, and so is also per-reference.
66 *
67 * TODO: add anything necessary for frame reordering
68 */
69 typedef struct AVFilterPicRef
70 {
71 AVFilterPic *pic; ///< the picture that this is a reference to
72 uint8_t *data[4]; ///< picture data for each plane
73 int linesize[4]; ///< number of bytes per line
74 int w; ///< image width
75 int h; ///< image height
76
77 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
78
79 AVRational pixel_aspect; ///< pixel aspect ratio
80
81 int perms; ///< permissions
82 #define AV_PERM_READ 0x01 ///< can read from the buffer
83 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
84 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
85 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
86 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
87 } AVFilterPicRef;
88
89 /**
90 * Add a new reference to a picture.
91 * @param ref an existing reference to the picture
92 * @param pmask a bitmask containing the allowable permissions in the new
93 * reference
94 * @return a new reference to the picture with the same properties as the
95 * old, excluding any permissions denied by pmask
96 */
97 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
98
99 /**
100 * Remove a reference to a picture. If this is the last reference to the
101 * picture, the picture itself is also automatically freed.
102 * @param ref reference to the picture
103 */
104 void avfilter_unref_pic(AVFilterPicRef *ref);
105
106 /**
107 * A list of supported formats for one end of a filter link. This is used
108 * during the format negotiation process to try to pick the best format to
109 * use to minimize the number of necessary conversions. Each filter gives a
110 * list of the formats supported by each input and output pad. The list
111 * given for each pad need not be distinct - they may be references to the
112 * same list of formats, as is often the case when a filter supports multiple
113 * formats, but will always outut the same format as it is given in input.
114 *
115 * In this way, a list of possible input formats and a list of possible
116 * output formats are associated with each link. When a set of formats is
117 * negotiated over a link, the input and output lists are merged to form a
118 * new list containing only the common elements of each list. In the case
119 * that there were no common elements, a format conversion is necessary.
120 * Otherwise, the lists are merged, and all other links which reference
121 * either of the format lists involved in the merge are also affected.
122 *
123 * For example, consider the filter chain:
124 * filter (a) --> (b) filter (b) --> (c) filter
125 *
126 * where the letters in parenthesis indicate a list of formats supported on
127 * the input or output of the link. Suppose the lists are as follows:
128 * (a) = {A, B}
129 * (b) = {A, B, C}
130 * (c) = {B, C}
131 *
132 * First, the first link's lists are merged, yielding:
133 * filter (a) --> (a) filter (a) --> (c) filter
134 *
135 * Notice that format list (b) now refers to the same list as filter list (a).
136 * Next, the lists for the second link are merged, yielding:
137 * filter (a) --> (a) filter (a) --> (a) filter
138 *
139 * where (a) = {B}.
140 *
141 * Unfortunately, when the format lists at the two ends of a link are merged,
142 * we must ensure that all links which reference either pre-merge format list
143 * get updated as well. Therefore, we have the format list structure store a
144 * pointer to each of the pointers to itself.
145 */
146 typedef struct AVFilterFormats AVFilterFormats;
147 struct AVFilterFormats
148 {
149 unsigned format_count; ///< number of formats
150 int *formats; ///< list of formats
151
152 unsigned refcount; ///< number of references to this list
153 AVFilterFormats ***refs; ///< references to this list
154 };
155
156 /**
157 * Helper function to create a list of supported formats. This is intended
158 * for use in AVFilter->query_formats().
159 * @param len the number of formats supported
160 * @param ... a list of the supported formats
161 * @return the format list, with no existing references
162 */
163 AVFilterFormats *avfilter_make_format_list(int len, ...);
164
165 /**
166 * Returns a list of all colorspaces supported by FFmpeg.
167 */
168 AVFilterFormats *avfilter_all_colorspaces(void);
169
170 /**
171 * If a and b share at least one common format, they are merged into a new
172 * format list which is returned. All the references to a and b are updated
173 * to point to this new list, and a and b are deallocated.
174 *
175 * If a and b do not share any common formats, neither is modified, and NULL
176 * is returned.
177 */
178 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
179
180 /** Adds *ref as a new reference to f */
181 void avfilter_formats_ref(AVFilterFormats *f, AVFilterFormats **ref);
182
183 /**
184 * Remove *ref as a reference to the format list it currently points to,
185 * deallocate that list if this was the last reference, and set *ref to NULL.
186 */
187 void avfilter_formats_unref(AVFilterFormats **ref);
188
189 /**
190 * A filter pad used for either input or output.
191 */
192 struct AVFilterPad
193 {
194 /**
195 * Pad name. The name is unique among inputs and among outputs, but an
196 * input may have the same name as an output. This may be NULL if this
197 * pad has no need to ever be referenced by name.
198 */
199 const char *name;
200
201 /**
202 * AVFilterPad type. Only video supported now, hopefully someone will
203 * add audio in the future.
204 */
205 enum CodecType type;
206
207 /**
208 * Minimum required permissions on incoming buffers. Any buffers with
209 * insufficient permissions will be automatically copied by the filter
210 * system to a new buffer which provides the needed access permissions.
211 *
212 * Input pads only.
213 */
214 int min_perms;
215
216 /**
217 * Permissions which are not accepted on incoming buffers. Any buffer
218 * which has any of these permissions set be automatically copied by the
219 * filter system to a new buffer which does not have those permissions.
220 * This can be used to easily disallow buffers with AV_PERM_REUSE.
221 *
222 * Input pads only.
223 */
224 int rej_perms;
225
226 /**
227 * Callback called before passing the first slice of a new frame. If
228 * NULL, the filter layer will default to storing a reference to the
229 * picture inside the link structure.
230 *
231 * Input video pads only.
232 */
233 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
234
235 /**
236 * Callback function to get a buffer. If NULL, the filter system will
237 * handle buffer requests.
238 *
239 * Input video pads only.
240 */
241 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
242
243 /**
244 * Callback called after the slices of a frame are completely sent. If
245 * NULL, the filter layer will default to releasing the reference stored
246 * in the link structure during start_frame().
247 *
248 * Input video pads only.
249 */
250 void (*end_frame)(AVFilterLink *link);
251
252 /**
253 * Slice drawing callback. This is where a filter receives video data
254 * and should do its processing.
255 *
256 * Input video pads only.
257 */
258 void (*draw_slice)(AVFilterLink *link, int y, int height);
259
260 /**
261 * Frame poll callback. This returns the number of immediately available
262 * frames. It should return a positive value if the next request_frame()
263 * is guaranteed to return one frame (with no delay).
264 *
265 * Defaults to just calling the source poll_frame() method.
266 *
267 * Output video pads only.
268 */
269 int (*poll_frame)(AVFilterLink *link);
270
271 /**
272 * Frame request callback. A call to this should result in at least one
273 * frame being output over the given link. This should return zero on
274 * success, and another value on error.
275 *
276 * Output video pads only.
277 */
278 int (*request_frame)(AVFilterLink *link);
279
280 /**
281 * Link configuration callback.
282 *
283 * For output pads, this should set the link properties such as
284 * width/height. This should NOT set the format property - that is
285 * negotiated between filters by the filter system using the
286 * query_formats() callback before this function is called.
287 *
288 * For input pads, this should check the properties of the link, and update
289 * the filter's internal state as necessary.
290 *
291 * For both input and output filters, this should return zero on success,
292 * and another value on error.
293 */
294 int (*config_props)(AVFilterLink *link);
295 };
296
297 /** Default handler for start_frame() for video inputs */
298 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
299 /** Default handler for end_frame() for video inputs */
300 void avfilter_default_end_frame(AVFilterLink *link);
301 /** Default handler for config_props() for video outputs */
302 int avfilter_default_config_output_link(AVFilterLink *link);
303 /** Default handler for config_props() for video inputs */
304 int avfilter_default_config_input_link (AVFilterLink *link);
305 /** Default handler for get_video_buffer() for video inputs */
306 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
307 int perms);
308 /**
309 * A helper for query_formats() which sets all links to the same list of
310 * formats. If there are no links hooked to this filter, the list of formats is
311 * freed.
312 */
313 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
314 /** Default handler for query_formats() */
315 int avfilter_default_query_formats(AVFilterContext *ctx);
316
317 void avfilter_formats_changeref(AVFilterFormats **oldref,
318 AVFilterFormats **newref);
319
320 /**
321 * Filter definition. This defines the pads a filter contains, and all the
322 * callback functions used to interact with the filter.
323 */
324 typedef struct
325 {
326 const char *name; ///< filter name
327
328 int priv_size; ///< size of private data to allocate for the filter
329
330 /**
331 * Filter initialization function. Args contains the user-supplied
332 * parameters. FIXME: maybe an AVOption-based system would be better?
333 * opaque is data provided by the code requesting creation of the filter,
334 * and is used to pass data to the filter.
335 */
336 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
337
338 /**
339 * Filter uninitialization function. Should deallocate any memory held
340 * by the filter, release any picture references, etc. This does not need
341 * to deallocate the AVFilterContext->priv memory itself.
342 */
343 void (*uninit)(AVFilterContext *ctx);
344
345 /**
346 * Query formats supported by the filter and its pads. Should set the
347 * in_formats for links connected to its output pads, and out_formats
348 * for links connected to its input pads.
349 *
350 * Should return zero on success.
351 */
352 int (*query_formats)(AVFilterContext *);
353
354 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
355 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
356 } AVFilter;
357
358 /** An instance of a filter */
359 struct AVFilterContext
360 {
361 AVClass *av_class; ///< needed for av_log()
362
363 AVFilter *filter; ///< the AVFilter of which this is an instance
364
365 char *name; ///< name of this filter instance
366
367 unsigned input_count; ///< number of input pads
368 AVFilterPad *input_pads; ///< array of input pads
369 AVFilterLink **inputs; ///< array of pointers to input links
370
371 unsigned output_count; ///< number of output pads
372 AVFilterPad *output_pads; ///< array of output pads
373 AVFilterLink **outputs; ///< array of pointers to output links
374
375 void *priv; ///< private data for use by the filter
376 };
377
378 /**
379 * A link between two filters. This contains pointers to the source and
380 * destination filters between which this link exists, and the indices of
381 * the pads involved. In addition, this link also contains the parameters
382 * which have been negotiated and agreed upon between the filter, such as
383 * image dimensions, format, etc
384 */
385 struct AVFilterLink
386 {
387 AVFilterContext *src; ///< source filter
388 unsigned int srcpad; ///< index of the output pad on the source filter
389
390 AVFilterContext *dst; ///< dest filter
391 unsigned int dstpad; ///< index of the input pad on the dest filter
392
393 /** stage of the initialization of the link properties (dimensions, etc) */
394 enum {
395 AVLINK_UNINIT = 0, ///< not started
396 AVLINK_STARTINIT, ///< started, but incomplete
397 AVLINK_INIT ///< complete
398 } init_state;
399
400 int w; ///< agreed upon image width
401 int h; ///< agreed upon image height
402 enum PixelFormat format; ///< agreed upon image colorspace
403
404 /**
405 * Lists of formats supported by the input and output filters respectively.
406 * These lists are used for negotiating the format to actually be used,
407 * which will be loaded into the format member, above, when chosen.
408 */
409 AVFilterFormats *in_formats;
410 AVFilterFormats *out_formats;
411
412 /**
413 * The picture reference currently being sent across the link by the source
414 * filter. This is used internally by the filter system to allow
415 * automatic copying of pictures which do not have sufficient permissions
416 * for the destination. This should not be accessed directly by the
417 * filters.
418 */
419 AVFilterPicRef *srcpic;
420
421 AVFilterPicRef *cur_pic;
422 AVFilterPicRef *outpic;
423 };
424
425 /**
426 * Link two filters together.
427 * @param src the source filter
428 * @param srcpad index of the output pad on the source filter
429 * @param dst the destination filter
430 * @param dstpad index of the input pad on the destination filter
431 * @return zero on success
432 */
433 int avfilter_link(AVFilterContext *src, unsigned srcpad,
434 AVFilterContext *dst, unsigned dstpad);
435
436 /**
437 * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
438 * @param filter the filter to negotiate the properties for its inputs
439 * @return zero on successful negotiation
440 */
441 int avfilter_config_links(AVFilterContext *filter);
442
443 /**
444 * Request a picture buffer with a specific set of permissions
445 * @param link the output link to the filter from which the picture will
446 * be requested
447 * @param perms the required access permissions
448 * @return A reference to the picture. This must be unreferenced with
449 * avfilter_unref_pic when you are finished with it.
450 */
451 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
452
453 /**
454 * Request an input frame from the filter at the other end of the link.
455 * @param link the input link
456 * @return zero on success
457 */
458 int avfilter_request_frame(AVFilterLink *link);
459
460 /**
461 * Poll a frame from the filter chain.
462 * @param link the input link
463 * @return the number of imediately available frames
464 */
465 int avfilter_poll_frame(AVFilterLink *link);
466
467 /**
468 * Notify the next filter of the start of a frame.
469 * @param link the output link the frame will be sent over
470 * @param picref A reference to the frame about to be sent. The data for this
471 * frame need only be valid once draw_slice() is called for that
472 * portion. The receiving filter will free this reference when
473 * it no longer needs it.
474 */
475 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
476
477 /**
478 * Notify the next filter that the current frame has finished
479 * @param link the output link the frame was sent over
480 */
481 void avfilter_end_frame(AVFilterLink *link);
482
483 /**
484 * Send a slice to the next filter.
485 * @param link the output link over which the frame is being sent
486 * @param y offset in pixels from the top of the image for this slice
487 * @param h height of this slice in pixels
488 */
489 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
490
491 /** Initialize the filter system. Registers all builtin filters */
492 void avfilter_init(void);
493
494 /** Initialize the filter system. Registers all builtin filters */
495 void avfilter_register_all(void);
496
497 /** Uninitialize the filter system. Unregisters all filters */
498 void avfilter_uninit(void);
499
500 /**
501 * Register a filter. This is only needed if you plan to use
502 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
503 * filter can still by instantiated with avfilter_open even if it is not
504 * registered.
505 * @param filter the filter to register
506 */
507 void avfilter_register(AVFilter *filter);
508
509 /**
510 * Gets a filter definition matching the given name.
511 * @param name the filter name to find
512 * @return the filter definition, if any matching one is registered.
513 * NULL if none found.
514 */
515 AVFilter *avfilter_get_by_name(const char *name);
516
517 /**
518 * Create a filter instance.
519 * @param filter the filter to create an instance of
520 * @param inst_name Name to give to the new instance. Can be NULL for none.
521 * @return Pointer to the new instance on success. NULL on failure.
522 */
523 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
524
525 /**
526 * Initialize a filter.
527 * @param filter the filter to initialize
528 * @param args A string of parameters to use when initializing the filter.
529 * The format and meaning of this string varies by filter.
530 * @param opaque Any extra non-string data needed by the filter. The meaning
531 * of this parameter varies by filter.
532 * @return zero on success
533 */
534 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
535
536 /**
537 * Destroy a filter.
538 * @param filter the filter to destroy
539 */
540 void avfilter_destroy(AVFilterContext *filter);
541
542 /**
543 * Insert a filter in the middle of an existing link.
544 * @param link the link into which the filter should be inserted
545 * @param filt the filter to be inserted
546 * @param in the input pad on the filter to connect
547 * @param out the output pad on the filter to connect
548 * @return zero on success
549 */
550 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
551 unsigned in, unsigned out);
552
553 /**
554 * Insert a new pad.
555 * @param idx Insertion point. Pad is inserted at the end if this point
556 * is beyond the end of the list of pads.
557 * @param count Pointer to the number of pads in the list
558 * @param padidx_off Offset within an AVFilterLink structure to the element
559 * to increment when inserting a new pad causes link
560 * numbering to change
561 * @param pads Pointer to the pointer to the beginning of the list of pads
562 * @param links Pointer to the pointer to the beginning of the list of links
563 * @param newpad The new pad to add. A copy is made when adding.
564 */
565 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
566 AVFilterPad **pads, AVFilterLink ***links,
567 AVFilterPad *newpad);
568
569 /** insert a new input pad for the filter */
570 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
571 AVFilterPad *p)
572 {
573 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
574 &f->input_pads, &f->inputs, p);
575 }
576
577 /** insert a new output pad for the filter */
578 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
579 AVFilterPad *p)
580 {
581 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
582 &f->output_pads, &f->outputs, p);
583 }
584
585 #endif /* FFMPEG_AVFILTER_H */