b12b7c7d81051ed27673ba76ca2b5cc336d38ad0
[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 AVFILTER_AVFILTER_H
23 #define AVFILTER_AVFILTER_H
24
25 #include "libavutil/avutil.h"
26
27 #define LIBAVFILTER_VERSION_MAJOR 1
28 #define LIBAVFILTER_VERSION_MINOR 57
29 #define LIBAVFILTER_VERSION_MICRO 0
30
31 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
32 LIBAVFILTER_VERSION_MINOR, \
33 LIBAVFILTER_VERSION_MICRO)
34 #define LIBAVFILTER_VERSION AV_VERSION(LIBAVFILTER_VERSION_MAJOR, \
35 LIBAVFILTER_VERSION_MINOR, \
36 LIBAVFILTER_VERSION_MICRO)
37 #define LIBAVFILTER_BUILD LIBAVFILTER_VERSION_INT
38
39 #include <stddef.h>
40 #include "libavcodec/avcodec.h"
41
42 /**
43 * Return the LIBAVFILTER_VERSION_INT constant.
44 */
45 unsigned avfilter_version(void);
46
47 /**
48 * Return the libavfilter build-time configuration.
49 */
50 const char *avfilter_configuration(void);
51
52 /**
53 * Return the libavfilter license.
54 */
55 const char *avfilter_license(void);
56
57
58 typedef struct AVFilterContext AVFilterContext;
59 typedef struct AVFilterLink AVFilterLink;
60 typedef struct AVFilterPad AVFilterPad;
61
62 /**
63 * A reference-counted buffer data type used by the filter system. Filters
64 * should not store pointers to this structure directly, but instead use the
65 * AVFilterBufferRef structure below.
66 */
67 typedef struct AVFilterBuffer {
68 uint8_t *data[8]; ///< buffer data for each plane/channel
69 int linesize[8]; ///< number of bytes per line
70
71 unsigned refcount; ///< number of references to this buffer
72
73 /** private data to be used by a custom free function */
74 void *priv;
75 /**
76 * A pointer to the function to deallocate this buffer if the default
77 * function is not sufficient. This could, for example, add the memory
78 * back into a memory pool to be reused later without the overhead of
79 * reallocating it from scratch.
80 */
81 void (*free)(struct AVFilterBuffer *buf);
82 } AVFilterBuffer;
83
84 #define AV_PERM_READ 0x01 ///< can read from the buffer
85 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
86 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
87 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
88 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
89
90 /**
91 * Audio specific properties in a reference to an AVFilterBuffer. Since
92 * AVFilterBufferRef is common to different media formats, audio specific
93 * per reference properties must be separated out.
94 */
95 typedef struct AVFilterBufferRefAudioProps {
96 int64_t channel_layout; ///< channel layout of audio buffer
97 int samples_nb; ///< number of audio samples
98 int size; ///< audio buffer size
99 uint32_t sample_rate; ///< audio buffer sample rate
100 int planar; ///< audio buffer - planar or packed
101 } AVFilterBufferRefAudioProps;
102
103 /**
104 * Video specific properties in a reference to an AVFilterBuffer. Since
105 * AVFilterBufferRef is common to different media formats, video specific
106 * per reference properties must be separated out.
107 */
108 typedef struct AVFilterBufferRefVideoProps {
109 int w; ///< image width
110 int h; ///< image height
111 AVRational pixel_aspect; ///< pixel aspect ratio
112 int interlaced; ///< is frame interlaced
113 int top_field_first; ///< field order
114 } AVFilterBufferRefVideoProps;
115
116 /**
117 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
118 * a buffer to, for example, crop image without any memcpy, the buffer origin
119 * and dimensions are per-reference properties. Linesize is also useful for
120 * image flipping, frame to field filters, etc, and so is also per-reference.
121 *
122 * TODO: add anything necessary for frame reordering
123 */
124 typedef struct AVFilterBufferRef {
125 AVFilterBuffer *buf; ///< the buffer that this is a reference to
126 uint8_t *data[8]; ///< picture/audio data for each plane
127 int linesize[8]; ///< number of bytes per line
128 int format; ///< media format
129
130 /**
131 * presentation timestamp. The time unit may change during
132 * filtering, as it is specified in the link and the filter code
133 * may need to rescale the PTS accordingly.
134 */
135 int64_t pts;
136 int64_t pos; ///< byte position in stream, -1 if unknown
137
138 int perms; ///< permissions, see the AV_PERM_* flags
139
140 enum AVMediaType type; ///< media type of buffer data
141 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
142 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
143 } AVFilterBufferRef;
144
145 /**
146 * Copy properties of src to dst, without copying the actual data
147 */
148 static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
149 {
150 // copy common properties
151 dst->pts = src->pts;
152 dst->pos = src->pos;
153
154 switch (src->type) {
155 case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
156 case AVMEDIA_TYPE_AUDIO: *dst->audio = *src->audio; break;
157 }
158 }
159
160 /**
161 * Add a new reference to a buffer.
162 *
163 * @param ref an existing reference to the buffer
164 * @param pmask a bitmask containing the allowable permissions in the new
165 * reference
166 * @return a new reference to the buffer with the same properties as the
167 * old, excluding any permissions denied by pmask
168 */
169 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
170
171 /**
172 * Remove a reference to a buffer. If this is the last reference to the
173 * buffer, the buffer itself is also automatically freed.
174 *
175 * @param ref reference to the buffer
176 */
177 void avfilter_unref_buffer(AVFilterBufferRef *ref);
178
179 /**
180 * A list of supported formats for one end of a filter link. This is used
181 * during the format negotiation process to try to pick the best format to
182 * use to minimize the number of necessary conversions. Each filter gives a
183 * list of the formats supported by each input and output pad. The list
184 * given for each pad need not be distinct - they may be references to the
185 * same list of formats, as is often the case when a filter supports multiple
186 * formats, but will always output the same format as it is given in input.
187 *
188 * In this way, a list of possible input formats and a list of possible
189 * output formats are associated with each link. When a set of formats is
190 * negotiated over a link, the input and output lists are merged to form a
191 * new list containing only the common elements of each list. In the case
192 * that there were no common elements, a format conversion is necessary.
193 * Otherwise, the lists are merged, and all other links which reference
194 * either of the format lists involved in the merge are also affected.
195 *
196 * For example, consider the filter chain:
197 * filter (a) --> (b) filter (b) --> (c) filter
198 *
199 * where the letters in parenthesis indicate a list of formats supported on
200 * the input or output of the link. Suppose the lists are as follows:
201 * (a) = {A, B}
202 * (b) = {A, B, C}
203 * (c) = {B, C}
204 *
205 * First, the first link's lists are merged, yielding:
206 * filter (a) --> (a) filter (a) --> (c) filter
207 *
208 * Notice that format list (b) now refers to the same list as filter list (a).
209 * Next, the lists for the second link are merged, yielding:
210 * filter (a) --> (a) filter (a) --> (a) filter
211 *
212 * where (a) = {B}.
213 *
214 * Unfortunately, when the format lists at the two ends of a link are merged,
215 * we must ensure that all links which reference either pre-merge format list
216 * get updated as well. Therefore, we have the format list structure store a
217 * pointer to each of the pointers to itself.
218 */
219 typedef struct AVFilterFormats {
220 unsigned format_count; ///< number of formats
221 int *formats; ///< list of media formats
222
223 unsigned refcount; ///< number of references to this list
224 struct AVFilterFormats ***refs; ///< references to this list
225 } AVFilterFormats;;
226
227 /**
228 * Create a list of supported formats. This is intended for use in
229 * AVFilter->query_formats().
230 *
231 * @param fmts list of media formats, terminated by -1
232 * @return the format list, with no existing references
233 */
234 AVFilterFormats *avfilter_make_format_list(const int *fmts);
235
236 /**
237 * Add fmt to the list of media formats contained in *avff.
238 * If *avff is NULL the function allocates the filter formats struct
239 * and puts its pointer in *avff.
240 *
241 * @return a non negative value in case of success, or a negative
242 * value corresponding to an AVERROR code in case of error
243 */
244 int avfilter_add_format(AVFilterFormats **avff, int fmt);
245
246 /**
247 * Return a list of all formats supported by FFmpeg for the given media type.
248 */
249 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
250
251 /**
252 * Return a format list which contains the intersection of the formats of
253 * a and b. Also, all the references of a, all the references of b, and
254 * a and b themselves will be deallocated.
255 *
256 * If a and b do not share any common formats, neither is modified, and NULL
257 * is returned.
258 */
259 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
260
261 /**
262 * Add *ref as a new reference to formats.
263 * That is the pointers will point like in the ascii art below:
264 * ________
265 * |formats |<--------.
266 * | ____ | ____|___________________
267 * | |refs| | | __|_
268 * | |* * | | | | | | AVFilterLink
269 * | |* *--------->|*ref|
270 * | |____| | | |____|
271 * |________| |________________________
272 */
273 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
274
275 /**
276 * If *ref is non-NULL, remove *ref as a reference to the format list
277 * it currently points to, deallocates that list if this was the last
278 * reference, and sets *ref to NULL.
279 *
280 * Before After
281 * ________ ________ NULL
282 * |formats |<--------. |formats | ^
283 * | ____ | ____|________________ | ____ | ____|________________
284 * | |refs| | | __|_ | |refs| | | __|_
285 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
286 * | |* *--------->|*ref| | |* | | | |*ref|
287 * | |____| | | |____| | |____| | | |____|
288 * |________| |_____________________ |________| |_____________________
289 */
290 void avfilter_formats_unref(AVFilterFormats **ref);
291
292 /**
293 *
294 * Before After
295 * ________ ________
296 * |formats |<---------. |formats |<---------.
297 * | ____ | ___|___ | ____ | ___|___
298 * | |refs| | | | | | |refs| | | | | NULL
299 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
300 * | |* * | | |_______| | |* * | | |_______| ___|___
301 * | |____| | | |____| | | | |
302 * |________| |________| |*oldref|
303 * |_______|
304 */
305 void avfilter_formats_changeref(AVFilterFormats **oldref,
306 AVFilterFormats **newref);
307
308 /**
309 * A filter pad used for either input or output.
310 */
311 struct AVFilterPad {
312 /**
313 * Pad name. The name is unique among inputs and among outputs, but an
314 * input may have the same name as an output. This may be NULL if this
315 * pad has no need to ever be referenced by name.
316 */
317 const char *name;
318
319 /**
320 * AVFilterPad type. Only video supported now, hopefully someone will
321 * add audio in the future.
322 */
323 enum AVMediaType type;
324
325 /**
326 * Minimum required permissions on incoming buffers. Any buffer with
327 * insufficient permissions will be automatically copied by the filter
328 * system to a new buffer which provides the needed access permissions.
329 *
330 * Input pads only.
331 */
332 int min_perms;
333
334 /**
335 * Permissions which are not accepted on incoming buffers. Any buffer
336 * which has any of these permissions set will be automatically copied
337 * by the filter system to a new buffer which does not have those
338 * permissions. This can be used to easily disallow buffers with
339 * AV_PERM_REUSE.
340 *
341 * Input pads only.
342 */
343 int rej_perms;
344
345 /**
346 * Callback called before passing the first slice of a new frame. If
347 * NULL, the filter layer will default to storing a reference to the
348 * picture inside the link structure.
349 *
350 * Input video pads only.
351 */
352 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
353
354 /**
355 * Callback function to get a video buffer. If NULL, the filter system will
356 * use avfilter_default_get_video_buffer().
357 *
358 * Input video pads only.
359 */
360 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
361
362 /**
363 * Callback function to get an audio buffer. If NULL, the filter system will
364 * use avfilter_default_get_audio_buffer().
365 *
366 * Input audio pads only.
367 */
368 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
369 enum SampleFormat sample_fmt, int size,
370 int64_t channel_layout, int planar);
371
372 /**
373 * Callback called after the slices of a frame are completely sent. If
374 * NULL, the filter layer will default to releasing the reference stored
375 * in the link structure during start_frame().
376 *
377 * Input video pads only.
378 */
379 void (*end_frame)(AVFilterLink *link);
380
381 /**
382 * Slice drawing callback. This is where a filter receives video data
383 * and should do its processing.
384 *
385 * Input video pads only.
386 */
387 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
388
389 /**
390 * Samples filtering callback. This is where a filter receives audio data
391 * and should do its processing.
392 *
393 * Input audio pads only.
394 */
395 void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
396
397 /**
398 * Frame poll callback. This returns the number of immediately available
399 * samples. It should return a positive value if the next request_frame()
400 * is guaranteed to return one frame (with no delay).
401 *
402 * Defaults to just calling the source poll_frame() method.
403 *
404 * Output video pads only.
405 */
406 int (*poll_frame)(AVFilterLink *link);
407
408 /**
409 * Frame request callback. A call to this should result in at least one
410 * frame being output over the given link. This should return zero on
411 * success, and another value on error.
412 *
413 * Output video pads only.
414 */
415 int (*request_frame)(AVFilterLink *link);
416
417 /**
418 * Link configuration callback.
419 *
420 * For output pads, this should set the link properties such as
421 * width/height. This should NOT set the format property - that is
422 * negotiated between filters by the filter system using the
423 * query_formats() callback before this function is called.
424 *
425 * For input pads, this should check the properties of the link, and update
426 * the filter's internal state as necessary.
427 *
428 * For both input and output filters, this should return zero on success,
429 * and another value on error.
430 */
431 int (*config_props)(AVFilterLink *link);
432 };
433
434 /** default handler for start_frame() for video inputs */
435 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
436
437 /** default handler for draw_slice() for video inputs */
438 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
439
440 /** default handler for end_frame() for video inputs */
441 void avfilter_default_end_frame(AVFilterLink *link);
442
443 /** default handler for filter_samples() for audio inputs */
444 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
445
446 /** default handler for config_props() for audio/video outputs */
447 int avfilter_default_config_output_link(AVFilterLink *link);
448
449 /** default handler for config_props() for audio/video inputs */
450 int avfilter_default_config_input_link (AVFilterLink *link);
451
452 /** default handler for get_video_buffer() for video inputs */
453 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
454 int perms, int w, int h);
455
456 /** default handler for get_audio_buffer() for audio inputs */
457 AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link, int perms,
458 enum SampleFormat sample_fmt, int size,
459 int64_t channel_layout, int planar);
460
461 /**
462 * A helper for query_formats() which sets all links to the same list of
463 * formats. If there are no links hooked to this filter, the list of formats is
464 * freed.
465 */
466 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
467
468 /** Default handler for query_formats() */
469 int avfilter_default_query_formats(AVFilterContext *ctx);
470
471 /** start_frame() handler for filters which simply pass video along */
472 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
473
474 /** draw_slice() handler for filters which simply pass video along */
475 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
476
477 /** end_frame() handler for filters which simply pass video along */
478 void avfilter_null_end_frame(AVFilterLink *link);
479
480 /** filter_samples() handler for filters which simply pass audio along */
481 void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
482
483 /** get_video_buffer() handler for filters which simply pass video along */
484 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
485 int perms, int w, int h);
486
487 /** get_audio_buffer() handler for filters which simply pass audio along */
488 AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link, int perms,
489 enum SampleFormat sample_fmt, int size,
490 int64_t channel_layout, int planar);
491
492 /**
493 * Filter definition. This defines the pads a filter contains, and all the
494 * callback functions used to interact with the filter.
495 */
496 typedef struct AVFilter {
497 const char *name; ///< filter name
498
499 int priv_size; ///< size of private data to allocate for the filter
500
501 /**
502 * Filter initialization function. Args contains the user-supplied
503 * parameters. FIXME: maybe an AVOption-based system would be better?
504 * opaque is data provided by the code requesting creation of the filter,
505 * and is used to pass data to the filter.
506 */
507 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
508
509 /**
510 * Filter uninitialization function. Should deallocate any memory held
511 * by the filter, release any buffer references, etc. This does not need
512 * to deallocate the AVFilterContext->priv memory itself.
513 */
514 void (*uninit)(AVFilterContext *ctx);
515
516 /**
517 * Queries formats supported by the filter and its pads, and sets the
518 * in_formats for links connected to its output pads, and out_formats
519 * for links connected to its input pads.
520 *
521 * @return zero on success, a negative value corresponding to an
522 * AVERROR code otherwise
523 */
524 int (*query_formats)(AVFilterContext *);
525
526 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
527 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
528
529 /**
530 * A description for the filter. You should use the
531 * NULL_IF_CONFIG_SMALL() macro to define it.
532 */
533 const char *description;
534 } AVFilter;
535
536 /** An instance of a filter */
537 struct AVFilterContext {
538 const AVClass *av_class; ///< needed for av_log()
539
540 AVFilter *filter; ///< the AVFilter of which this is an instance
541
542 char *name; ///< name of this filter instance
543
544 unsigned input_count; ///< number of input pads
545 AVFilterPad *input_pads; ///< array of input pads
546 AVFilterLink **inputs; ///< array of pointers to input links
547
548 unsigned output_count; ///< number of output pads
549 AVFilterPad *output_pads; ///< array of output pads
550 AVFilterLink **outputs; ///< array of pointers to output links
551
552 void *priv; ///< private data for use by the filter
553 };
554
555 /**
556 * A link between two filters. This contains pointers to the source and
557 * destination filters between which this link exists, and the indexes of
558 * the pads involved. In addition, this link also contains the parameters
559 * which have been negotiated and agreed upon between the filter, such as
560 * image dimensions, format, etc.
561 */
562 struct AVFilterLink {
563 AVFilterContext *src; ///< source filter
564 AVFilterPad *srcpad; ///< output pad on the source filter
565
566 AVFilterContext *dst; ///< dest filter
567 AVFilterPad *dstpad; ///< input pad on the dest filter
568
569 /** stage of the initialization of the link properties (dimensions, etc) */
570 enum {
571 AVLINK_UNINIT = 0, ///< not started
572 AVLINK_STARTINIT, ///< started, but incomplete
573 AVLINK_INIT ///< complete
574 } init_state;
575
576 enum AVMediaType type; ///< filter media type
577
578 /* These two parameters apply only to video */
579 int w; ///< agreed upon image width
580 int h; ///< agreed upon image height
581 /* These two parameters apply only to audio */
582 int64_t channel_layout; ///< channel layout of current buffer (see avcodec.h)
583 int64_t sample_rate; ///< samples per second
584
585 int format; ///< agreed upon media format
586
587 /**
588 * Lists of formats supported by the input and output filters respectively.
589 * These lists are used for negotiating the format to actually be used,
590 * which will be loaded into the format member, above, when chosen.
591 */
592 AVFilterFormats *in_formats;
593 AVFilterFormats *out_formats;
594
595 /**
596 * The buffer reference currently being sent across the link by the source
597 * filter. This is used internally by the filter system to allow
598 * automatic copying of buffers which do not have sufficient permissions
599 * for the destination. This should not be accessed directly by the
600 * filters.
601 */
602 AVFilterBufferRef *src_buf;
603
604 AVFilterBufferRef *cur_buf;
605 AVFilterBufferRef *out_buf;
606
607 /**
608 * Define the time base used by the PTS of the frames/samples
609 * which will pass through this link.
610 * During the configuration stage, each filter is supposed to
611 * change only the output timebase, while the timebase of the
612 * input link is assumed to be an unchangeable property.
613 */
614 AVRational time_base;
615 };
616
617 /**
618 * Link two filters together.
619 *
620 * @param src the source filter
621 * @param srcpad index of the output pad on the source filter
622 * @param dst the destination filter
623 * @param dstpad index of the input pad on the destination filter
624 * @return zero on success
625 */
626 int avfilter_link(AVFilterContext *src, unsigned srcpad,
627 AVFilterContext *dst, unsigned dstpad);
628
629 /**
630 * Negotiate the media format, dimensions, etc of all inputs to a filter.
631 *
632 * @param filter the filter to negotiate the properties for its inputs
633 * @return zero on successful negotiation
634 */
635 int avfilter_config_links(AVFilterContext *filter);
636
637 /**
638 * Request a picture buffer with a specific set of permissions.
639 *
640 * @param link the output link to the filter from which the buffer will
641 * be requested
642 * @param perms the required access permissions
643 * @param w the minimum width of the buffer to allocate
644 * @param h the minimum height of the buffer to allocate
645 * @return A reference to the buffer. This must be unreferenced with
646 * avfilter_unref_buffer when you are finished with it.
647 */
648 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
649 int w, int h);
650
651 /**
652 * Request an audio samples buffer with a specific set of permissions.
653 *
654 * @param link the output link to the filter from which the buffer will
655 * be requested
656 * @param perms the required access permissions
657 * @param sample_fmt the format of each sample in the buffer to allocate
658 * @param size the buffer size in bytes
659 * @param channel_layout the number and type of channels per sample in the buffer to allocate
660 * @param planar audio data layout - planar or packed
661 * @return A reference to the samples. This must be unreferenced with
662 * avfilter_unref_buffer when you are finished with it.
663 */
664 AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,
665 enum SampleFormat sample_fmt, int size,
666 int64_t channel_layout, int planar);
667
668 /**
669 * Request an input frame from the filter at the other end of the link.
670 *
671 * @param link the input link
672 * @return zero on success
673 */
674 int avfilter_request_frame(AVFilterLink *link);
675
676 /**
677 * Poll a frame from the filter chain.
678 *
679 * @param link the input link
680 * @return the number of immediately available frames, a negative
681 * number in case of error
682 */
683 int avfilter_poll_frame(AVFilterLink *link);
684
685 /**
686 * Notifie the next filter of the start of a frame.
687 *
688 * @param link the output link the frame will be sent over
689 * @param picref A reference to the frame about to be sent. The data for this
690 * frame need only be valid once draw_slice() is called for that
691 * portion. The receiving filter will free this reference when
692 * it no longer needs it.
693 */
694 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
695
696 /**
697 * Notifie the next filter that the current frame has finished.
698 *
699 * @param link the output link the frame was sent over
700 */
701 void avfilter_end_frame(AVFilterLink *link);
702
703 /**
704 * Send a slice to the next filter.
705 *
706 * Slices have to be provided in sequential order, either in
707 * top-bottom or bottom-top order. If slices are provided in
708 * non-sequential order the behavior of the function is undefined.
709 *
710 * @param link the output link over which the frame is being sent
711 * @param y offset in pixels from the top of the image for this slice
712 * @param h height of this slice in pixels
713 * @param slice_dir the assumed direction for sending slices,
714 * from the top slice to the bottom slice if the value is 1,
715 * from the bottom slice to the top slice if the value is -1,
716 * for other values the behavior of the function is undefined.
717 */
718 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
719
720 /**
721 * Send a buffer of audio samples to the next filter.
722 *
723 * @param link the output link over which the audio samples are being sent
724 * @param samplesref a reference to the buffer of audio samples being sent. The
725 * receiving filter will free this reference when it no longer
726 * needs it or pass it on to the next filter.
727 */
728 void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
729
730 /** Initialize the filter system. Register all builtin filters. */
731 void avfilter_register_all(void);
732
733 /** Uninitialize the filter system. Unregister all filters. */
734 void avfilter_uninit(void);
735
736 /**
737 * Register a filter. This is only needed if you plan to use
738 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
739 * filter can still by instantiated with avfilter_open even if it is not
740 * registered.
741 *
742 * @param filter the filter to register
743 * @return 0 if the registration was succesfull, a negative value
744 * otherwise
745 */
746 int avfilter_register(AVFilter *filter);
747
748 /**
749 * Get a filter definition matching the given name.
750 *
751 * @param name the filter name to find
752 * @return the filter definition, if any matching one is registered.
753 * NULL if none found.
754 */
755 AVFilter *avfilter_get_by_name(const char *name);
756
757 /**
758 * If filter is NULL, returns a pointer to the first registered filter pointer,
759 * if filter is non-NULL, returns the next pointer after filter.
760 * If the returned pointer points to NULL, the last registered filter
761 * was already reached.
762 */
763 AVFilter **av_filter_next(AVFilter **filter);
764
765 /**
766 * Create a filter instance.
767 *
768 * @param filter_ctx put here a pointer to the created filter context
769 * on success, NULL on failure
770 * @param filter the filter to create an instance of
771 * @param inst_name Name to give to the new instance. Can be NULL for none.
772 * @return >= 0 in case of success, a negative error code otherwise
773 */
774 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
775
776 /**
777 * Initialize a filter.
778 *
779 * @param filter the filter to initialize
780 * @param args A string of parameters to use when initializing the filter.
781 * The format and meaning of this string varies by filter.
782 * @param opaque Any extra non-string data needed by the filter. The meaning
783 * of this parameter varies by filter.
784 * @return zero on success
785 */
786 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
787
788 /**
789 * Destroy a filter.
790 *
791 * @param filter the filter to destroy
792 */
793 void avfilter_destroy(AVFilterContext *filter);
794
795 /**
796 * Insert a filter in the middle of an existing link.
797 *
798 * @param link the link into which the filter should be inserted
799 * @param filt the filter to be inserted
800 * @param filt_srcpad_idx the input pad on the filter to connect
801 * @param filt_dstpad_idx the output pad on the filter to connect
802 * @return zero on success
803 */
804 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
805 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
806
807 /**
808 * Insert a new pad.
809 *
810 * @param idx Insertion point. Pad is inserted at the end if this point
811 * is beyond the end of the list of pads.
812 * @param count Pointer to the number of pads in the list
813 * @param padidx_off Offset within an AVFilterLink structure to the element
814 * to increment when inserting a new pad causes link
815 * numbering to change
816 * @param pads Pointer to the pointer to the beginning of the list of pads
817 * @param links Pointer to the pointer to the beginning of the list of links
818 * @param newpad The new pad to add. A copy is made when adding.
819 */
820 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
821 AVFilterPad **pads, AVFilterLink ***links,
822 AVFilterPad *newpad);
823
824 /** Insert a new input pad for the filter. */
825 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
826 AVFilterPad *p)
827 {
828 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
829 &f->input_pads, &f->inputs, p);
830 }
831
832 /** Insert a new output pad for the filter. */
833 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
834 AVFilterPad *p)
835 {
836 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
837 &f->output_pads, &f->outputs, p);
838 }
839
840 #endif /* AVFILTER_AVFILTER_H */