lavfi: add a frame_rate field to AVFilterLink.
[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 /**
26 * @file
27 * @ingroup lavfi
28 * Main libavfilter public API header
29 */
30
31 /**
32 * @defgroup lavfi Libavfilter - graph-based frame editing library
33 * @{
34 */
35
36 #include "libavutil/attributes.h"
37 #include "libavutil/avutil.h"
38 #include "libavutil/frame.h"
39 #include "libavutil/log.h"
40 #include "libavutil/samplefmt.h"
41 #include "libavutil/pixfmt.h"
42 #include "libavutil/rational.h"
43
44 #include <stddef.h>
45
46 #include "libavfilter/version.h"
47
48 /**
49 * Return the LIBAVFILTER_VERSION_INT constant.
50 */
51 unsigned avfilter_version(void);
52
53 /**
54 * Return the libavfilter build-time configuration.
55 */
56 const char *avfilter_configuration(void);
57
58 /**
59 * Return the libavfilter license.
60 */
61 const char *avfilter_license(void);
62
63
64 typedef struct AVFilterContext AVFilterContext;
65 typedef struct AVFilterLink AVFilterLink;
66 typedef struct AVFilterPad AVFilterPad;
67 typedef struct AVFilterFormats AVFilterFormats;
68
69 /**
70 * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
71 * AVFilter.inputs/outputs).
72 */
73 int avfilter_pad_count(const AVFilterPad *pads);
74
75 /**
76 * Get the name of an AVFilterPad.
77 *
78 * @param pads an array of AVFilterPads
79 * @param pad_idx index of the pad in the array it; is the caller's
80 * responsibility to ensure the index is valid
81 *
82 * @return name of the pad_idx'th pad in pads
83 */
84 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
85
86 /**
87 * Get the type of an AVFilterPad.
88 *
89 * @param pads an array of AVFilterPads
90 * @param pad_idx index of the pad in the array; it is the caller's
91 * responsibility to ensure the index is valid
92 *
93 * @return type of the pad_idx'th pad in pads
94 */
95 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
96
97 /**
98 * The number of the filter inputs is not determined just by AVFilter.inputs.
99 * The filter might add additional inputs during initialization depending on the
100 * options supplied to it.
101 */
102 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
103 /**
104 * The number of the filter outputs is not determined just by AVFilter.outputs.
105 * The filter might add additional outputs during initialization depending on
106 * the options supplied to it.
107 */
108 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
109 /**
110 * The filter supports multithreading by splitting frames into multiple parts
111 * and processing them concurrently.
112 */
113 #define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
114
115 /**
116 * Filter definition. This defines the pads a filter contains, and all the
117 * callback functions used to interact with the filter.
118 */
119 typedef struct AVFilter {
120 /**
121 * Filter name. Must be non-NULL and unique among filters.
122 */
123 const char *name;
124
125 /**
126 * A description of the filter. May be NULL.
127 *
128 * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
129 */
130 const char *description;
131
132 /**
133 * List of inputs, terminated by a zeroed element.
134 *
135 * NULL if there are no (static) inputs. Instances of filters with
136 * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
137 * this list.
138 */
139 const AVFilterPad *inputs;
140 /**
141 * List of outputs, terminated by a zeroed element.
142 *
143 * NULL if there are no (static) outputs. Instances of filters with
144 * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
145 * this list.
146 */
147 const AVFilterPad *outputs;
148
149 /**
150 * A class for the private data, used to declare filter private AVOptions.
151 * This field is NULL for filters that do not declare any options.
152 *
153 * If this field is non-NULL, the first member of the filter private data
154 * must be a pointer to AVClass, which will be set by libavfilter generic
155 * code to this class.
156 */
157 const AVClass *priv_class;
158
159 /**
160 * A combination of AVFILTER_FLAG_*
161 */
162 int flags;
163
164 /*****************************************************************
165 * All fields below this line are not part of the public API. They
166 * may not be used outside of libavfilter and can be changed and
167 * removed at will.
168 * New public fields should be added right above.
169 *****************************************************************
170 */
171
172 /**
173 * Filter initialization function.
174 *
175 * This callback will be called only once during the filter lifetime, after
176 * all the options have been set, but before links between filters are
177 * established and format negotiation is done.
178 *
179 * Basic filter initialization should be done here. Filters with dynamic
180 * inputs and/or outputs should create those inputs/outputs here based on
181 * provided options. No more changes to this filter's inputs/outputs can be
182 * done after this callback.
183 *
184 * This callback must not assume that the filter links exist or frame
185 * parameters are known.
186 *
187 * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
188 * initialization fails, so this callback does not have to clean up on
189 * failure.
190 *
191 * @return 0 on success, a negative AVERROR on failure
192 */
193 int (*init)(AVFilterContext *ctx);
194
195 /**
196 * Should be set instead of @ref AVFilter.init "init" by the filters that
197 * want to pass a dictionary of AVOptions to nested contexts that are
198 * allocated during init.
199 *
200 * On return, the options dict should be freed and replaced with one that
201 * contains all the options which could not be processed by this filter (or
202 * with NULL if all the options were processed).
203 *
204 * Otherwise the semantics is the same as for @ref AVFilter.init "init".
205 */
206 int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
207
208 /**
209 * Filter uninitialization function.
210 *
211 * Called only once right before the filter is freed. Should deallocate any
212 * memory held by the filter, release any buffer references, etc. It does
213 * not need to deallocate the AVFilterContext.priv memory itself.
214 *
215 * This callback may be called even if @ref AVFilter.init "init" was not
216 * called or failed, so it must be prepared to handle such a situation.
217 */
218 void (*uninit)(AVFilterContext *ctx);
219
220 /**
221 * Query formats supported by the filter on its inputs and outputs.
222 *
223 * This callback is called after the filter is initialized (so the inputs
224 * and outputs are fixed), shortly before the format negotiation. This
225 * callback may be called more than once.
226 *
227 * This callback must set AVFilterLink.out_formats on every input link and
228 * AVFilterLink.in_formats on every output link to a list of pixel/sample
229 * formats that the filter supports on that link. For audio links, this
230 * filter must also set @ref AVFilterLink.in_samplerates "in_samplerates" /
231 * @ref AVFilterLink.out_samplerates "out_samplerates" and
232 * @ref AVFilterLink.in_channel_layouts "in_channel_layouts" /
233 * @ref AVFilterLink.out_channel_layouts "out_channel_layouts" analogously.
234 *
235 * This callback may be NULL for filters with one input, in which case
236 * libavfilter assumes that it supports all input formats and preserves
237 * them on output.
238 *
239 * @return zero on success, a negative value corresponding to an
240 * AVERROR code otherwise
241 */
242 int (*query_formats)(AVFilterContext *);
243
244 int priv_size; ///< size of private data to allocate for the filter
245
246 /**
247 * Used by the filter registration system. Must not be touched by any other
248 * code.
249 */
250 struct AVFilter *next;
251 } AVFilter;
252
253 /**
254 * Process multiple parts of the frame concurrently.
255 */
256 #define AVFILTER_THREAD_SLICE (1 << 0)
257
258 typedef struct AVFilterInternal AVFilterInternal;
259
260 /** An instance of a filter */
261 struct AVFilterContext {
262 const AVClass *av_class; ///< needed for av_log()
263
264 const AVFilter *filter; ///< the AVFilter of which this is an instance
265
266 char *name; ///< name of this filter instance
267
268 AVFilterPad *input_pads; ///< array of input pads
269 AVFilterLink **inputs; ///< array of pointers to input links
270 unsigned nb_inputs; ///< number of input pads
271
272 AVFilterPad *output_pads; ///< array of output pads
273 AVFilterLink **outputs; ///< array of pointers to output links
274 unsigned nb_outputs; ///< number of output pads
275
276 void *priv; ///< private data for use by the filter
277
278 struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
279
280 /**
281 * Type of multithreading being allowed/used. A combination of
282 * AVFILTER_THREAD_* flags.
283 *
284 * May be set by the caller before initializing the filter to forbid some
285 * or all kinds of multithreading for this filter. The default is allowing
286 * everything.
287 *
288 * When the filter is initialized, this field is combined using bit AND with
289 * AVFilterGraph.thread_type to get the final mask used for determining
290 * allowed threading types. I.e. a threading type needs to be set in both
291 * to be allowed.
292 *
293 * After the filter is initialzed, libavfilter sets this field to the
294 * threading type that is actually used (0 for no multithreading).
295 */
296 int thread_type;
297
298 /**
299 * An opaque struct for libavfilter internal use.
300 */
301 AVFilterInternal *internal;
302 };
303
304 /**
305 * A link between two filters. This contains pointers to the source and
306 * destination filters between which this link exists, and the indexes of
307 * the pads involved. In addition, this link also contains the parameters
308 * which have been negotiated and agreed upon between the filter, such as
309 * image dimensions, format, etc.
310 */
311 struct AVFilterLink {
312 AVFilterContext *src; ///< source filter
313 AVFilterPad *srcpad; ///< output pad on the source filter
314
315 AVFilterContext *dst; ///< dest filter
316 AVFilterPad *dstpad; ///< input pad on the dest filter
317
318 enum AVMediaType type; ///< filter media type
319
320 /* These parameters apply only to video */
321 int w; ///< agreed upon image width
322 int h; ///< agreed upon image height
323 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
324 /* These two parameters apply only to audio */
325 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
326 int sample_rate; ///< samples per second
327
328 int format; ///< agreed upon media format
329
330 /**
331 * Define the time base used by the PTS of the frames/samples
332 * which will pass through this link.
333 * During the configuration stage, each filter is supposed to
334 * change only the output timebase, while the timebase of the
335 * input link is assumed to be an unchangeable property.
336 */
337 AVRational time_base;
338
339 /*****************************************************************
340 * All fields below this line are not part of the public API. They
341 * may not be used outside of libavfilter and can be changed and
342 * removed at will.
343 * New public fields should be added right above.
344 *****************************************************************
345 */
346 /**
347 * Lists of formats supported by the input and output filters respectively.
348 * These lists are used for negotiating the format to actually be used,
349 * which will be loaded into the format member, above, when chosen.
350 */
351 AVFilterFormats *in_formats;
352 AVFilterFormats *out_formats;
353
354 /**
355 * Lists of channel layouts and sample rates used for automatic
356 * negotiation.
357 */
358 AVFilterFormats *in_samplerates;
359 AVFilterFormats *out_samplerates;
360 struct AVFilterChannelLayouts *in_channel_layouts;
361 struct AVFilterChannelLayouts *out_channel_layouts;
362
363 /**
364 * Audio only, the destination filter sets this to a non-zero value to
365 * request that buffers with the given number of samples should be sent to
366 * it. AVFilterPad.needs_fifo must also be set on the corresponding input
367 * pad.
368 * Last buffer before EOF will be padded with silence.
369 */
370 int request_samples;
371
372 /** stage of the initialization of the link properties (dimensions, etc) */
373 enum {
374 AVLINK_UNINIT = 0, ///< not started
375 AVLINK_STARTINIT, ///< started, but incomplete
376 AVLINK_INIT ///< complete
377 } init_state;
378
379 /**
380 * Frame rate of the stream on the link, or 1/0 if unknown or variable;
381 * if left to 0/0, will be automatically copied from the first input
382 * of the source filter if it exists.
383 *
384 * Sources should set it to the real constant frame rate.
385 * If the source frame rate is unknown or variable, set this to 1/0.
386 * Filters should update it if necessary depending on their function.
387 * Sinks can use it to set a default output frame rate.
388 */
389 AVRational frame_rate;
390 };
391
392 /**
393 * Link two filters together.
394 *
395 * @param src the source filter
396 * @param srcpad index of the output pad on the source filter
397 * @param dst the destination filter
398 * @param dstpad index of the input pad on the destination filter
399 * @return zero on success
400 */
401 int avfilter_link(AVFilterContext *src, unsigned srcpad,
402 AVFilterContext *dst, unsigned dstpad);
403
404 /**
405 * Negotiate the media format, dimensions, etc of all inputs to a filter.
406 *
407 * @param filter the filter to negotiate the properties for its inputs
408 * @return zero on successful negotiation
409 */
410 int avfilter_config_links(AVFilterContext *filter);
411
412 /** Initialize the filter system. Register all builtin filters. */
413 void avfilter_register_all(void);
414
415 #if FF_API_OLD_FILTER_REGISTER
416 /** Uninitialize the filter system. Unregister all filters. */
417 attribute_deprecated
418 void avfilter_uninit(void);
419 #endif
420
421 /**
422 * Register a filter. This is only needed if you plan to use
423 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
424 * filter can still by instantiated with avfilter_graph_alloc_filter even if it
425 * is not registered.
426 *
427 * @param filter the filter to register
428 * @return 0 if the registration was succesfull, a negative value
429 * otherwise
430 */
431 int avfilter_register(AVFilter *filter);
432
433 /**
434 * Get a filter definition matching the given name.
435 *
436 * @param name the filter name to find
437 * @return the filter definition, if any matching one is registered.
438 * NULL if none found.
439 */
440 #if !FF_API_NOCONST_GET_NAME
441 const
442 #endif
443 AVFilter *avfilter_get_by_name(const char *name);
444
445 /**
446 * Iterate over all registered filters.
447 * @return If prev is non-NULL, next registered filter after prev or NULL if
448 * prev is the last filter. If prev is NULL, return the first registered filter.
449 */
450 const AVFilter *avfilter_next(const AVFilter *prev);
451
452 #if FF_API_OLD_FILTER_REGISTER
453 /**
454 * If filter is NULL, returns a pointer to the first registered filter pointer,
455 * if filter is non-NULL, returns the next pointer after filter.
456 * If the returned pointer points to NULL, the last registered filter
457 * was already reached.
458 * @deprecated use avfilter_next()
459 */
460 attribute_deprecated
461 AVFilter **av_filter_next(AVFilter **filter);
462 #endif
463
464 #if FF_API_AVFILTER_OPEN
465 /**
466 * Create a filter instance.
467 *
468 * @param filter_ctx put here a pointer to the created filter context
469 * on success, NULL on failure
470 * @param filter the filter to create an instance of
471 * @param inst_name Name to give to the new instance. Can be NULL for none.
472 * @return >= 0 in case of success, a negative error code otherwise
473 * @deprecated use avfilter_graph_alloc_filter() instead
474 */
475 attribute_deprecated
476 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
477 #endif
478
479
480 #if FF_API_AVFILTER_INIT_FILTER
481 /**
482 * Initialize a filter.
483 *
484 * @param filter the filter to initialize
485 * @param args A string of parameters to use when initializing the filter.
486 * The format and meaning of this string varies by filter.
487 * @param opaque Any extra non-string data needed by the filter. The meaning
488 * of this parameter varies by filter.
489 * @return zero on success
490 */
491 attribute_deprecated
492 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
493 #endif
494
495 /**
496 * Initialize a filter with the supplied parameters.
497 *
498 * @param ctx uninitialized filter context to initialize
499 * @param args Options to initialize the filter with. This must be a
500 * ':'-separated list of options in the 'key=value' form.
501 * May be NULL if the options have been set directly using the
502 * AVOptions API or there are no options that need to be set.
503 * @return 0 on success, a negative AVERROR on failure
504 */
505 int avfilter_init_str(AVFilterContext *ctx, const char *args);
506
507 /**
508 * Initialize a filter with the supplied dictionary of options.
509 *
510 * @param ctx uninitialized filter context to initialize
511 * @param options An AVDictionary filled with options for this filter. On
512 * return this parameter will be destroyed and replaced with
513 * a dict containing options that were not found. This dictionary
514 * must be freed by the caller.
515 * May be NULL, then this function is equivalent to
516 * avfilter_init_str() with the second parameter set to NULL.
517 * @return 0 on success, a negative AVERROR on failure
518 *
519 * @note This function and avfilter_init_str() do essentially the same thing,
520 * the difference is in manner in which the options are passed. It is up to the
521 * calling code to choose whichever is more preferable. The two functions also
522 * behave differently when some of the provided options are not declared as
523 * supported by the filter. In such a case, avfilter_init_str() will fail, but
524 * this function will leave those extra options in the options AVDictionary and
525 * continue as usual.
526 */
527 int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
528
529 /**
530 * Free a filter context. This will also remove the filter from its
531 * filtergraph's list of filters.
532 *
533 * @param filter the filter to free
534 */
535 void avfilter_free(AVFilterContext *filter);
536
537 /**
538 * Insert a filter in the middle of an existing link.
539 *
540 * @param link the link into which the filter should be inserted
541 * @param filt the filter to be inserted
542 * @param filt_srcpad_idx the input pad on the filter to connect
543 * @param filt_dstpad_idx the output pad on the filter to connect
544 * @return zero on success
545 */
546 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
547 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
548
549 /**
550 * @return AVClass for AVFilterContext.
551 *
552 * @see av_opt_find().
553 */
554 const AVClass *avfilter_get_class(void);
555
556 typedef struct AVFilterGraphInternal AVFilterGraphInternal;
557
558 /**
559 * A function pointer passed to the @ref AVFilterGraph.execute callback to be
560 * executed multiple times, possibly in parallel.
561 *
562 * @param ctx the filter context the job belongs to
563 * @param arg an opaque parameter passed through from @ref
564 * AVFilterGraph.execute
565 * @param jobnr the index of the job being executed
566 * @param nb_jobs the total number of jobs
567 *
568 * @return 0 on success, a negative AVERROR on error
569 */
570 typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
571
572 /**
573 * A function executing multiple jobs, possibly in parallel.
574 *
575 * @param ctx the filter context to which the jobs belong
576 * @param func the function to be called multiple times
577 * @param arg the argument to be passed to func
578 * @param ret a nb_jobs-sized array to be filled with return values from each
579 * invocation of func
580 * @param nb_jobs the number of jobs to execute
581 *
582 * @return 0 on success, a negative AVERROR on error
583 */
584 typedef int (avfilter_execute_func)(AVFilterContext *ctx, avfilter_action_func *func,
585 void *arg, int *ret, int nb_jobs);
586
587 typedef struct AVFilterGraph {
588 const AVClass *av_class;
589 AVFilterContext **filters;
590 unsigned nb_filters;
591
592 char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
593 char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
594
595 /**
596 * Type of multithreading allowed for filters in this graph. A combination
597 * of AVFILTER_THREAD_* flags.
598 *
599 * May be set by the caller at any point, the setting will apply to all
600 * filters initialized after that. The default is allowing everything.
601 *
602 * When a filter in this graph is initialized, this field is combined using
603 * bit AND with AVFilterContext.thread_type to get the final mask used for
604 * determining allowed threading types. I.e. a threading type needs to be
605 * set in both to be allowed.
606 */
607 int thread_type;
608
609 /**
610 * Maximum number of threads used by filters in this graph. May be set by
611 * the caller before adding any filters to the filtergraph. Zero (the
612 * default) means that the number of threads is determined automatically.
613 */
614 int nb_threads;
615
616 /**
617 * Opaque object for libavfilter internal use.
618 */
619 AVFilterGraphInternal *internal;
620
621 /**
622 * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
623 * be used from callbacks like @ref AVFilterGraph.execute.
624 * Libavfilter will not touch this field in any way.
625 */
626 void *opaque;
627
628 /**
629 * This callback may be set by the caller immediately after allocating the
630 * graph and before adding any filters to it, to provide a custom
631 * multithreading implementation.
632 *
633 * If set, filters with slice threading capability will call this callback
634 * to execute multiple jobs in parallel.
635 *
636 * If this field is left unset, libavfilter will use its internal
637 * implementation, which may or may not be multithreaded depending on the
638 * platform and build options.
639 */
640 avfilter_execute_func *execute;
641 } AVFilterGraph;
642
643 /**
644 * Allocate a filter graph.
645 *
646 * @return the allocated filter graph on success or NULL.
647 */
648 AVFilterGraph *avfilter_graph_alloc(void);
649
650 /**
651 * Create a new filter instance in a filter graph.
652 *
653 * @param graph graph in which the new filter will be used
654 * @param filter the filter to create an instance of
655 * @param name Name to give to the new instance (will be copied to
656 * AVFilterContext.name). This may be used by the caller to identify
657 * different filters, libavfilter itself assigns no semantics to
658 * this parameter. May be NULL.
659 *
660 * @return the context of the newly created filter instance (note that it is
661 * also retrievable directly through AVFilterGraph.filters or with
662 * avfilter_graph_get_filter()) on success or NULL or failure.
663 */
664 AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
665 const AVFilter *filter,
666 const char *name);
667
668 /**
669 * Get a filter instance with name name from graph.
670 *
671 * @return the pointer to the found filter instance or NULL if it
672 * cannot be found.
673 */
674 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name);
675
676 #if FF_API_AVFILTER_OPEN
677 /**
678 * Add an existing filter instance to a filter graph.
679 *
680 * @param graphctx the filter graph
681 * @param filter the filter to be added
682 *
683 * @deprecated use avfilter_graph_alloc_filter() to allocate a filter in a
684 * filter graph
685 */
686 attribute_deprecated
687 int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
688 #endif
689
690 /**
691 * Create and add a filter instance into an existing graph.
692 * The filter instance is created from the filter filt and inited
693 * with the parameters args and opaque.
694 *
695 * In case of success put in *filt_ctx the pointer to the created
696 * filter instance, otherwise set *filt_ctx to NULL.
697 *
698 * @param name the instance name to give to the created filter instance
699 * @param graph_ctx the filter graph
700 * @return a negative AVERROR error code in case of failure, a non
701 * negative value otherwise
702 */
703 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
704 const char *name, const char *args, void *opaque,
705 AVFilterGraph *graph_ctx);
706
707 /**
708 * Check validity and configure all the links and formats in the graph.
709 *
710 * @param graphctx the filter graph
711 * @param log_ctx context used for logging
712 * @return 0 in case of success, a negative AVERROR code otherwise
713 */
714 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
715
716 /**
717 * Free a graph, destroy its links, and set *graph to NULL.
718 * If *graph is NULL, do nothing.
719 */
720 void avfilter_graph_free(AVFilterGraph **graph);
721
722 /**
723 * A linked-list of the inputs/outputs of the filter chain.
724 *
725 * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
726 * where it is used to communicate open (unlinked) inputs and outputs from and
727 * to the caller.
728 * This struct specifies, per each not connected pad contained in the graph, the
729 * filter context and the pad index required for establishing a link.
730 */
731 typedef struct AVFilterInOut {
732 /** unique name for this input/output in the list */
733 char *name;
734
735 /** filter context associated to this input/output */
736 AVFilterContext *filter_ctx;
737
738 /** index of the filt_ctx pad to use for linking */
739 int pad_idx;
740
741 /** next input/input in the list, NULL if this is the last */
742 struct AVFilterInOut *next;
743 } AVFilterInOut;
744
745 /**
746 * Allocate a single AVFilterInOut entry.
747 * Must be freed with avfilter_inout_free().
748 * @return allocated AVFilterInOut on success, NULL on failure.
749 */
750 AVFilterInOut *avfilter_inout_alloc(void);
751
752 /**
753 * Free the supplied list of AVFilterInOut and set *inout to NULL.
754 * If *inout is NULL, do nothing.
755 */
756 void avfilter_inout_free(AVFilterInOut **inout);
757
758 /**
759 * Add a graph described by a string to a graph.
760 *
761 * @param graph the filter graph where to link the parsed graph context
762 * @param filters string to be parsed
763 * @param inputs linked list to the inputs of the graph
764 * @param outputs linked list to the outputs of the graph
765 * @return zero on success, a negative AVERROR code on error
766 */
767 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
768 AVFilterInOut *inputs, AVFilterInOut *outputs,
769 void *log_ctx);
770
771 /**
772 * Add a graph described by a string to a graph.
773 *
774 * @param[in] graph the filter graph where to link the parsed graph context
775 * @param[in] filters string to be parsed
776 * @param[out] inputs a linked list of all free (unlinked) inputs of the
777 * parsed graph will be returned here. It is to be freed
778 * by the caller using avfilter_inout_free().
779 * @param[out] outputs a linked list of all free (unlinked) outputs of the
780 * parsed graph will be returned here. It is to be freed by the
781 * caller using avfilter_inout_free().
782 * @return zero on success, a negative AVERROR code on error
783 *
784 * @note the difference between avfilter_graph_parse2() and
785 * avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
786 * the lists of inputs and outputs, which therefore must be known before calling
787 * the function. On the other hand, avfilter_graph_parse2() \em returns the
788 * inputs and outputs that are left unlinked after parsing the graph and the
789 * caller then deals with them. Another difference is that in
790 * avfilter_graph_parse(), the inputs parameter describes inputs of the
791 * <em>already existing</em> part of the graph; i.e. from the point of view of
792 * the newly created part, they are outputs. Similarly the outputs parameter
793 * describes outputs of the already existing filters, which are provided as
794 * inputs to the parsed filters.
795 * avfilter_graph_parse2() takes the opposite approach -- it makes no reference
796 * whatsoever to already existing parts of the graph and the inputs parameter
797 * will on return contain inputs of the newly parsed part of the graph.
798 * Analogously the outputs parameter will contain outputs of the newly created
799 * filters.
800 */
801 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
802 AVFilterInOut **inputs,
803 AVFilterInOut **outputs);
804
805 /**
806 * @}
807 */
808
809 #endif /* AVFILTER_AVFILTER_H */