Disable annoying warning without changing behavior
[libav.git] / libavfilter / avfilter.h
1 /*
2 * filter layer
3 * Copyright (c) 2007 Bobby Bingham
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 #include "libavutil/log.h"
27 #include "libavutil/samplefmt.h"
28 #include "libavutil/pixfmt.h"
29 #include "libavutil/rational.h"
30 #include "libavcodec/avcodec.h"
31
32 #define LIBAVFILTER_VERSION_MAJOR 2
33 #define LIBAVFILTER_VERSION_MINOR 14
34 #define LIBAVFILTER_VERSION_MICRO 0
35
36 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
37 LIBAVFILTER_VERSION_MINOR, \
38 LIBAVFILTER_VERSION_MICRO)
39 #define LIBAVFILTER_VERSION AV_VERSION(LIBAVFILTER_VERSION_MAJOR, \
40 LIBAVFILTER_VERSION_MINOR, \
41 LIBAVFILTER_VERSION_MICRO)
42 #define LIBAVFILTER_BUILD LIBAVFILTER_VERSION_INT
43
44 #include <stddef.h>
45
46 /**
47 * Return the LIBAVFILTER_VERSION_INT constant.
48 */
49 unsigned avfilter_version(void);
50
51 /**
52 * Return the libavfilter build-time configuration.
53 */
54 const char *avfilter_configuration(void);
55
56 /**
57 * Return the libavfilter license.
58 */
59 const char *avfilter_license(void);
60
61
62 typedef struct AVFilterContext AVFilterContext;
63 typedef struct AVFilterLink AVFilterLink;
64 typedef struct AVFilterPad AVFilterPad;
65
66 /**
67 * A reference-counted buffer data type used by the filter system. Filters
68 * should not store pointers to this structure directly, but instead use the
69 * AVFilterBufferRef structure below.
70 */
71 typedef struct AVFilterBuffer {
72 uint8_t *data[8]; ///< buffer data for each plane/channel
73 int linesize[8]; ///< number of bytes per line
74
75 unsigned refcount; ///< number of references to this buffer
76
77 /** private data to be used by a custom free function */
78 void *priv;
79 /**
80 * A pointer to the function to deallocate this buffer if the default
81 * function is not sufficient. This could, for example, add the memory
82 * back into a memory pool to be reused later without the overhead of
83 * reallocating it from scratch.
84 */
85 void (*free)(struct AVFilterBuffer *buf);
86
87 int format; ///< media format
88 int w, h; ///< width and height of the allocated buffer
89 } AVFilterBuffer;
90
91 #define AV_PERM_READ 0x01 ///< can read from the buffer
92 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
93 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
94 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
95 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
96 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
97
98 /**
99 * Audio specific properties in a reference to an AVFilterBuffer. Since
100 * AVFilterBufferRef is common to different media formats, audio specific
101 * per reference properties must be separated out.
102 */
103 typedef struct AVFilterBufferRefAudioProps {
104 uint64_t channel_layout; ///< channel layout of audio buffer
105 int nb_samples; ///< number of audio samples
106 int size; ///< audio buffer size
107 uint32_t sample_rate; ///< audio buffer sample rate
108 int planar; ///< audio buffer - planar or packed
109 } AVFilterBufferRefAudioProps;
110
111 /**
112 * Video specific properties in a reference to an AVFilterBuffer. Since
113 * AVFilterBufferRef is common to different media formats, video specific
114 * per reference properties must be separated out.
115 */
116 typedef struct AVFilterBufferRefVideoProps {
117 int w; ///< image width
118 int h; ///< image height
119 AVRational pixel_aspect; ///< pixel aspect ratio
120 int interlaced; ///< is frame interlaced
121 int top_field_first; ///< field order
122 enum AVPictureType pict_type; ///< picture type of the frame
123 int key_frame; ///< 1 -> keyframe, 0-> not
124 } AVFilterBufferRefVideoProps;
125
126 /**
127 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
128 * a buffer to, for example, crop image without any memcpy, the buffer origin
129 * and dimensions are per-reference properties. Linesize is also useful for
130 * image flipping, frame to field filters, etc, and so is also per-reference.
131 *
132 * TODO: add anything necessary for frame reordering
133 */
134 typedef struct AVFilterBufferRef {
135 AVFilterBuffer *buf; ///< the buffer that this is a reference to
136 uint8_t *data[8]; ///< picture/audio data for each plane
137 int linesize[8]; ///< number of bytes per line
138 int format; ///< media format
139
140 /**
141 * presentation timestamp. The time unit may change during
142 * filtering, as it is specified in the link and the filter code
143 * may need to rescale the PTS accordingly.
144 */
145 int64_t pts;
146 int64_t pos; ///< byte position in stream, -1 if unknown
147
148 int perms; ///< permissions, see the AV_PERM_* flags
149
150 enum AVMediaType type; ///< media type of buffer data
151 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
152 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
153 } AVFilterBufferRef;
154
155 /**
156 * Copy properties of src to dst, without copying the actual data
157 */
158 static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
159 {
160 // copy common properties
161 dst->pts = src->pts;
162 dst->pos = src->pos;
163
164 switch (src->type) {
165 case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
166 case AVMEDIA_TYPE_AUDIO: *dst->audio = *src->audio; break;
167 default: break;
168 }
169 }
170
171 /**
172 * Add a new reference to a buffer.
173 *
174 * @param ref an existing reference to the buffer
175 * @param pmask a bitmask containing the allowable permissions in the new
176 * reference
177 * @return a new reference to the buffer with the same properties as the
178 * old, excluding any permissions denied by pmask
179 */
180 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
181
182 /**
183 * Remove a reference to a buffer. If this is the last reference to the
184 * buffer, the buffer itself is also automatically freed.
185 *
186 * @param ref reference to the buffer, may be NULL
187 */
188 void avfilter_unref_buffer(AVFilterBufferRef *ref);
189
190 /**
191 * A list of supported formats for one end of a filter link. This is used
192 * during the format negotiation process to try to pick the best format to
193 * use to minimize the number of necessary conversions. Each filter gives a
194 * list of the formats supported by each input and output pad. The list
195 * given for each pad need not be distinct - they may be references to the
196 * same list of formats, as is often the case when a filter supports multiple
197 * formats, but will always output the same format as it is given in input.
198 *
199 * In this way, a list of possible input formats and a list of possible
200 * output formats are associated with each link. When a set of formats is
201 * negotiated over a link, the input and output lists are merged to form a
202 * new list containing only the common elements of each list. In the case
203 * that there were no common elements, a format conversion is necessary.
204 * Otherwise, the lists are merged, and all other links which reference
205 * either of the format lists involved in the merge are also affected.
206 *
207 * For example, consider the filter chain:
208 * filter (a) --> (b) filter (b) --> (c) filter
209 *
210 * where the letters in parenthesis indicate a list of formats supported on
211 * the input or output of the link. Suppose the lists are as follows:
212 * (a) = {A, B}
213 * (b) = {A, B, C}
214 * (c) = {B, C}
215 *
216 * First, the first link's lists are merged, yielding:
217 * filter (a) --> (a) filter (a) --> (c) filter
218 *
219 * Notice that format list (b) now refers to the same list as filter list (a).
220 * Next, the lists for the second link are merged, yielding:
221 * filter (a) --> (a) filter (a) --> (a) filter
222 *
223 * where (a) = {B}.
224 *
225 * Unfortunately, when the format lists at the two ends of a link are merged,
226 * we must ensure that all links which reference either pre-merge format list
227 * get updated as well. Therefore, we have the format list structure store a
228 * pointer to each of the pointers to itself.
229 */
230 typedef struct AVFilterFormats {
231 unsigned format_count; ///< number of formats
232 int *formats; ///< list of media formats
233
234 unsigned refcount; ///< number of references to this list
235 struct AVFilterFormats ***refs; ///< references to this list
236 } AVFilterFormats;
237
238 /**
239 * Create a list of supported formats. This is intended for use in
240 * AVFilter->query_formats().
241 *
242 * @param fmts list of media formats, terminated by -1
243 * @return the format list, with no existing references
244 */
245 AVFilterFormats *avfilter_make_format_list(const int *fmts);
246
247 /**
248 * Add fmt to the list of media formats contained in *avff.
249 * If *avff is NULL the function allocates the filter formats struct
250 * and puts its pointer in *avff.
251 *
252 * @return a non negative value in case of success, or a negative
253 * value corresponding to an AVERROR code in case of error
254 */
255 int avfilter_add_format(AVFilterFormats **avff, int fmt);
256
257 /**
258 * Return a list of all formats supported by Libav for the given media type.
259 */
260 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
261
262 /**
263 * Return a format list which contains the intersection of the formats of
264 * a and b. Also, all the references of a, all the references of b, and
265 * a and b themselves will be deallocated.
266 *
267 * If a and b do not share any common formats, neither is modified, and NULL
268 * is returned.
269 */
270 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
271
272 /**
273 * Add *ref as a new reference to formats.
274 * That is the pointers will point like in the ascii art below:
275 * ________
276 * |formats |<--------.
277 * | ____ | ____|___________________
278 * | |refs| | | __|_
279 * | |* * | | | | | | AVFilterLink
280 * | |* *--------->|*ref|
281 * | |____| | | |____|
282 * |________| |________________________
283 */
284 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
285
286 /**
287 * If *ref is non-NULL, remove *ref as a reference to the format list
288 * it currently points to, deallocates that list if this was the last
289 * reference, and sets *ref to NULL.
290 *
291 * Before After
292 * ________ ________ NULL
293 * |formats |<--------. |formats | ^
294 * | ____ | ____|________________ | ____ | ____|________________
295 * | |refs| | | __|_ | |refs| | | __|_
296 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
297 * | |* *--------->|*ref| | |* | | | |*ref|
298 * | |____| | | |____| | |____| | | |____|
299 * |________| |_____________________ |________| |_____________________
300 */
301 void avfilter_formats_unref(AVFilterFormats **ref);
302
303 /**
304 *
305 * Before After
306 * ________ ________
307 * |formats |<---------. |formats |<---------.
308 * | ____ | ___|___ | ____ | ___|___
309 * | |refs| | | | | | |refs| | | | | NULL
310 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
311 * | |* * | | |_______| | |* * | | |_______| ___|___
312 * | |____| | | |____| | | | |
313 * |________| |________| |*oldref|
314 * |_______|
315 */
316 void avfilter_formats_changeref(AVFilterFormats **oldref,
317 AVFilterFormats **newref);
318
319 /**
320 * A filter pad used for either input or output.
321 */
322 struct AVFilterPad {
323 /**
324 * Pad name. The name is unique among inputs and among outputs, but an
325 * input may have the same name as an output. This may be NULL if this
326 * pad has no need to ever be referenced by name.
327 */
328 const char *name;
329
330 /**
331 * AVFilterPad type. Only video supported now, hopefully someone will
332 * add audio in the future.
333 */
334 enum AVMediaType type;
335
336 /**
337 * Minimum required permissions on incoming buffers. Any buffer with
338 * insufficient permissions will be automatically copied by the filter
339 * system to a new buffer which provides the needed access permissions.
340 *
341 * Input pads only.
342 */
343 int min_perms;
344
345 /**
346 * Permissions which are not accepted on incoming buffers. Any buffer
347 * which has any of these permissions set will be automatically copied
348 * by the filter system to a new buffer which does not have those
349 * permissions. This can be used to easily disallow buffers with
350 * AV_PERM_REUSE.
351 *
352 * Input pads only.
353 */
354 int rej_perms;
355
356 /**
357 * Callback called before passing the first slice of a new frame. If
358 * NULL, the filter layer will default to storing a reference to the
359 * picture inside the link structure.
360 *
361 * Input video pads only.
362 */
363 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
364
365 /**
366 * Callback function to get a video buffer. If NULL, the filter system will
367 * use avfilter_default_get_video_buffer().
368 *
369 * Input video pads only.
370 */
371 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
372
373 /**
374 * Callback function to get an audio buffer. If NULL, the filter system will
375 * use avfilter_default_get_audio_buffer().
376 *
377 * Input audio pads only.
378 */
379 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
380 enum AVSampleFormat sample_fmt, int size,
381 uint64_t channel_layout, int planar);
382
383 /**
384 * Callback called after the slices of a frame are completely sent. If
385 * NULL, the filter layer will default to releasing the reference stored
386 * in the link structure during start_frame().
387 *
388 * Input video pads only.
389 */
390 void (*end_frame)(AVFilterLink *link);
391
392 /**
393 * Slice drawing callback. This is where a filter receives video data
394 * and should do its processing.
395 *
396 * Input video pads only.
397 */
398 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
399
400 /**
401 * Samples filtering callback. This is where a filter receives audio data
402 * and should do its processing.
403 *
404 * Input audio pads only.
405 */
406 void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
407
408 /**
409 * Frame poll callback. This returns the number of immediately available
410 * samples. It should return a positive value if the next request_frame()
411 * is guaranteed to return one frame (with no delay).
412 *
413 * Defaults to just calling the source poll_frame() method.
414 *
415 * Output video pads only.
416 */
417 int (*poll_frame)(AVFilterLink *link);
418
419 /**
420 * Frame request callback. A call to this should result in at least one
421 * frame being output over the given link. This should return zero on
422 * success, and another value on error.
423 *
424 * Output video pads only.
425 */
426 int (*request_frame)(AVFilterLink *link);
427
428 /**
429 * Link configuration callback.
430 *
431 * For output pads, this should set the link properties such as
432 * width/height. This should NOT set the format property - that is
433 * negotiated between filters by the filter system using the
434 * query_formats() callback before this function is called.
435 *
436 * For input pads, this should check the properties of the link, and update
437 * the filter's internal state as necessary.
438 *
439 * For both input and output filters, this should return zero on success,
440 * and another value on error.
441 */
442 int (*config_props)(AVFilterLink *link);
443 };
444
445 /** default handler for start_frame() for video inputs */
446 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
447
448 /** default handler for draw_slice() for video inputs */
449 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
450
451 /** default handler for end_frame() for video inputs */
452 void avfilter_default_end_frame(AVFilterLink *link);
453
454 /** default handler for filter_samples() for audio inputs */
455 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
456
457 /** default handler for config_props() for audio/video outputs */
458 int avfilter_default_config_output_link(AVFilterLink *link);
459
460 /** default handler for config_props() for audio/video inputs */
461 int avfilter_default_config_input_link (AVFilterLink *link);
462
463 /** default handler for get_video_buffer() for video inputs */
464 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
465 int perms, int w, int h);
466
467 /** default handler for get_audio_buffer() for audio inputs */
468 AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link, int perms,
469 enum AVSampleFormat sample_fmt, int size,
470 uint64_t channel_layout, int planar);
471
472 /**
473 * A helper for query_formats() which sets all links to the same list of
474 * formats. If there are no links hooked to this filter, the list of formats is
475 * freed.
476 */
477 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
478
479 /** Default handler for query_formats() */
480 int avfilter_default_query_formats(AVFilterContext *ctx);
481
482 /** start_frame() handler for filters which simply pass video along */
483 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
484
485 /** draw_slice() handler for filters which simply pass video along */
486 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
487
488 /** end_frame() handler for filters which simply pass video along */
489 void avfilter_null_end_frame(AVFilterLink *link);
490
491 /** filter_samples() handler for filters which simply pass audio along */
492 void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
493
494 /** get_video_buffer() handler for filters which simply pass video along */
495 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
496 int perms, int w, int h);
497
498 /** get_audio_buffer() handler for filters which simply pass audio along */
499 AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link, int perms,
500 enum AVSampleFormat sample_fmt, int size,
501 uint64_t channel_layout, int planar);
502
503 /**
504 * Filter definition. This defines the pads a filter contains, and all the
505 * callback functions used to interact with the filter.
506 */
507 typedef struct AVFilter {
508 const char *name; ///< filter name
509
510 int priv_size; ///< size of private data to allocate for the filter
511
512 /**
513 * Filter initialization function. Args contains the user-supplied
514 * parameters. FIXME: maybe an AVOption-based system would be better?
515 * opaque is data provided by the code requesting creation of the filter,
516 * and is used to pass data to the filter.
517 */
518 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
519
520 /**
521 * Filter uninitialization function. Should deallocate any memory held
522 * by the filter, release any buffer references, etc. This does not need
523 * to deallocate the AVFilterContext->priv memory itself.
524 */
525 void (*uninit)(AVFilterContext *ctx);
526
527 /**
528 * Queries formats supported by the filter and its pads, and sets the
529 * in_formats for links connected to its output pads, and out_formats
530 * for links connected to its input pads.
531 *
532 * @return zero on success, a negative value corresponding to an
533 * AVERROR code otherwise
534 */
535 int (*query_formats)(AVFilterContext *);
536
537 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
538 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
539
540 /**
541 * A description for the filter. You should use the
542 * NULL_IF_CONFIG_SMALL() macro to define it.
543 */
544 const char *description;
545 } AVFilter;
546
547 /** An instance of a filter */
548 struct AVFilterContext {
549 const AVClass *av_class; ///< needed for av_log()
550
551 AVFilter *filter; ///< the AVFilter of which this is an instance
552
553 char *name; ///< name of this filter instance
554
555 unsigned input_count; ///< number of input pads
556 AVFilterPad *input_pads; ///< array of input pads
557 AVFilterLink **inputs; ///< array of pointers to input links
558
559 unsigned output_count; ///< number of output pads
560 AVFilterPad *output_pads; ///< array of output pads
561 AVFilterLink **outputs; ///< array of pointers to output links
562
563 void *priv; ///< private data for use by the filter
564 };
565
566 /**
567 * A link between two filters. This contains pointers to the source and
568 * destination filters between which this link exists, and the indexes of
569 * the pads involved. In addition, this link also contains the parameters
570 * which have been negotiated and agreed upon between the filter, such as
571 * image dimensions, format, etc.
572 */
573 struct AVFilterLink {
574 AVFilterContext *src; ///< source filter
575 AVFilterPad *srcpad; ///< output pad on the source filter
576
577 AVFilterContext *dst; ///< dest filter
578 AVFilterPad *dstpad; ///< input pad on the dest filter
579
580 /** stage of the initialization of the link properties (dimensions, etc) */
581 enum {
582 AVLINK_UNINIT = 0, ///< not started
583 AVLINK_STARTINIT, ///< started, but incomplete
584 AVLINK_INIT ///< complete
585 } init_state;
586
587 enum AVMediaType type; ///< filter media type
588
589 /* These parameters apply only to video */
590 int w; ///< agreed upon image width
591 int h; ///< agreed upon image height
592 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
593 /* These two parameters apply only to audio */
594 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/audioconvert.h)
595 int64_t sample_rate; ///< samples per second
596
597 int format; ///< agreed upon media format
598
599 /**
600 * Lists of formats supported by the input and output filters respectively.
601 * These lists are used for negotiating the format to actually be used,
602 * which will be loaded into the format member, above, when chosen.
603 */
604 AVFilterFormats *in_formats;
605 AVFilterFormats *out_formats;
606
607 /**
608 * The buffer reference currently being sent across the link by the source
609 * filter. This is used internally by the filter system to allow
610 * automatic copying of buffers which do not have sufficient permissions
611 * for the destination. This should not be accessed directly by the
612 * filters.
613 */
614 AVFilterBufferRef *src_buf;
615
616 AVFilterBufferRef *cur_buf;
617 AVFilterBufferRef *out_buf;
618
619 /**
620 * Define the time base used by the PTS of the frames/samples
621 * which will pass through this link.
622 * During the configuration stage, each filter is supposed to
623 * change only the output timebase, while the timebase of the
624 * input link is assumed to be an unchangeable property.
625 */
626 AVRational time_base;
627 };
628
629 /**
630 * Link two filters together.
631 *
632 * @param src the source filter
633 * @param srcpad index of the output pad on the source filter
634 * @param dst the destination filter
635 * @param dstpad index of the input pad on the destination filter
636 * @return zero on success
637 */
638 int avfilter_link(AVFilterContext *src, unsigned srcpad,
639 AVFilterContext *dst, unsigned dstpad);
640
641 /**
642 * Negotiate the media format, dimensions, etc of all inputs to a filter.
643 *
644 * @param filter the filter to negotiate the properties for its inputs
645 * @return zero on successful negotiation
646 */
647 int avfilter_config_links(AVFilterContext *filter);
648
649 /**
650 * Request a picture buffer with a specific set of permissions.
651 *
652 * @param link the output link to the filter from which the buffer will
653 * be requested
654 * @param perms the required access permissions
655 * @param w the minimum width of the buffer to allocate
656 * @param h the minimum height of the buffer to allocate
657 * @return A reference to the buffer. This must be unreferenced with
658 * avfilter_unref_buffer when you are finished with it.
659 */
660 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
661 int w, int h);
662
663 /**
664 * Create a buffer reference wrapped around an already allocated image
665 * buffer.
666 *
667 * @param data pointers to the planes of the image to reference
668 * @param linesize linesizes for the planes of the image to reference
669 * @param perms the required access permissions
670 * @param w the width of the image specified by the data and linesize arrays
671 * @param h the height of the image specified by the data and linesize arrays
672 * @param format the pixel format of the image specified by the data and linesize arrays
673 */
674 AVFilterBufferRef *
675 avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int perms,
676 int w, int h, enum PixelFormat format);
677
678 /**
679 * Request an audio samples buffer with a specific set of permissions.
680 *
681 * @param link the output link to the filter from which the buffer will
682 * be requested
683 * @param perms the required access permissions
684 * @param sample_fmt the format of each sample in the buffer to allocate
685 * @param size the buffer size in bytes
686 * @param channel_layout the number and type of channels per sample in the buffer to allocate
687 * @param planar audio data layout - planar or packed
688 * @return A reference to the samples. This must be unreferenced with
689 * avfilter_unref_buffer when you are finished with it.
690 */
691 AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,
692 enum AVSampleFormat sample_fmt, int size,
693 uint64_t channel_layout, int planar);
694
695 /**
696 * Request an input frame from the filter at the other end of the link.
697 *
698 * @param link the input link
699 * @return zero on success
700 */
701 int avfilter_request_frame(AVFilterLink *link);
702
703 /**
704 * Poll a frame from the filter chain.
705 *
706 * @param link the input link
707 * @return the number of immediately available frames, a negative
708 * number in case of error
709 */
710 int avfilter_poll_frame(AVFilterLink *link);
711
712 /**
713 * Notify the next filter of the start of a frame.
714 *
715 * @param link the output link the frame will be sent over
716 * @param picref A reference to the frame about to be sent. The data for this
717 * frame need only be valid once draw_slice() is called for that
718 * portion. The receiving filter will free this reference when
719 * it no longer needs it.
720 */
721 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
722
723 /**
724 * Notifie the next filter that the current frame has finished.
725 *
726 * @param link the output link the frame was sent over
727 */
728 void avfilter_end_frame(AVFilterLink *link);
729
730 /**
731 * Send a slice to the next filter.
732 *
733 * Slices have to be provided in sequential order, either in
734 * top-bottom or bottom-top order. If slices are provided in
735 * non-sequential order the behavior of the function is undefined.
736 *
737 * @param link the output link over which the frame is being sent
738 * @param y offset in pixels from the top of the image for this slice
739 * @param h height of this slice in pixels
740 * @param slice_dir the assumed direction for sending slices,
741 * from the top slice to the bottom slice if the value is 1,
742 * from the bottom slice to the top slice if the value is -1,
743 * for other values the behavior of the function is undefined.
744 */
745 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
746
747 /**
748 * Send a buffer of audio samples to the next filter.
749 *
750 * @param link the output link over which the audio samples are being sent
751 * @param samplesref a reference to the buffer of audio samples being sent. The
752 * receiving filter will free this reference when it no longer
753 * needs it or pass it on to the next filter.
754 */
755 void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
756
757 /** Initialize the filter system. Register all builtin filters. */
758 void avfilter_register_all(void);
759
760 /** Uninitialize the filter system. Unregister all filters. */
761 void avfilter_uninit(void);
762
763 /**
764 * Register a filter. This is only needed if you plan to use
765 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
766 * filter can still by instantiated with avfilter_open even if it is not
767 * registered.
768 *
769 * @param filter the filter to register
770 * @return 0 if the registration was succesfull, a negative value
771 * otherwise
772 */
773 int avfilter_register(AVFilter *filter);
774
775 /**
776 * Get a filter definition matching the given name.
777 *
778 * @param name the filter name to find
779 * @return the filter definition, if any matching one is registered.
780 * NULL if none found.
781 */
782 AVFilter *avfilter_get_by_name(const char *name);
783
784 /**
785 * If filter is NULL, returns a pointer to the first registered filter pointer,
786 * if filter is non-NULL, returns the next pointer after filter.
787 * If the returned pointer points to NULL, the last registered filter
788 * was already reached.
789 */
790 AVFilter **av_filter_next(AVFilter **filter);
791
792 /**
793 * Create a filter instance.
794 *
795 * @param filter_ctx put here a pointer to the created filter context
796 * on success, NULL on failure
797 * @param filter the filter to create an instance of
798 * @param inst_name Name to give to the new instance. Can be NULL for none.
799 * @return >= 0 in case of success, a negative error code otherwise
800 */
801 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
802
803 /**
804 * Initialize a filter.
805 *
806 * @param filter the filter to initialize
807 * @param args A string of parameters to use when initializing the filter.
808 * The format and meaning of this string varies by filter.
809 * @param opaque Any extra non-string data needed by the filter. The meaning
810 * of this parameter varies by filter.
811 * @return zero on success
812 */
813 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
814
815 /**
816 * Free a filter context.
817 *
818 * @param filter the filter to free
819 */
820 void avfilter_free(AVFilterContext *filter);
821
822 /**
823 * Insert a filter in the middle of an existing link.
824 *
825 * @param link the link into which the filter should be inserted
826 * @param filt the filter to be inserted
827 * @param filt_srcpad_idx the input pad on the filter to connect
828 * @param filt_dstpad_idx the output pad on the filter to connect
829 * @return zero on success
830 */
831 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
832 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
833
834 /**
835 * Insert a new pad.
836 *
837 * @param idx Insertion point. Pad is inserted at the end if this point
838 * is beyond the end of the list of pads.
839 * @param count Pointer to the number of pads in the list
840 * @param padidx_off Offset within an AVFilterLink structure to the element
841 * to increment when inserting a new pad causes link
842 * numbering to change
843 * @param pads Pointer to the pointer to the beginning of the list of pads
844 * @param links Pointer to the pointer to the beginning of the list of links
845 * @param newpad The new pad to add. A copy is made when adding.
846 */
847 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
848 AVFilterPad **pads, AVFilterLink ***links,
849 AVFilterPad *newpad);
850
851 /** Insert a new input pad for the filter. */
852 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
853 AVFilterPad *p)
854 {
855 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
856 &f->input_pads, &f->inputs, p);
857 }
858
859 /** Insert a new output pad for the filter. */
860 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
861 AVFilterPad *p)
862 {
863 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
864 &f->output_pads, &f->outputs, p);
865 }
866
867 /**
868 * Copy the frame properties of src to dst, without copying the actual
869 * image data.
870 *
871 * @return 0 on success, a negative number on error.
872 */
873 int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
874
875 #endif /* AVFILTER_AVFILTER_H */