3 * Copyright (c) 2007 Bobby Bingham
5 * This file is part of Libav.
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.
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.
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
22 #ifndef AVFILTER_AVFILTER_H
23 #define AVFILTER_AVFILTER_H
28 * Main libavfilter public API header
32 * @defgroup lavfi Libavfilter - graph-based frame editing library
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"
46 #include "libavfilter/version.h"
49 * Return the LIBAVFILTER_VERSION_INT constant.
51 unsigned avfilter_version(void);
54 * Return the libavfilter build-time configuration.
56 const char *avfilter_configuration(void);
59 * Return the libavfilter license.
61 const char *avfilter_license(void);
64 typedef struct AVFilterContext AVFilterContext;
65 typedef struct AVFilterLink AVFilterLink;
66 typedef struct AVFilterPad AVFilterPad;
67 typedef struct AVFilterFormats AVFilterFormats;
70 * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
71 * AVFilter.inputs/outputs).
73 int avfilter_pad_count(const AVFilterPad *pads);
76 * Get the name of an AVFilterPad.
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
82 * @return name of the pad_idx'th pad in pads
84 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
87 * Get the type of an AVFilterPad.
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
93 * @return type of the pad_idx'th pad in pads
95 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
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.
102 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
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.
108 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
110 * The filter supports multithreading by splitting frames into multiple parts
111 * and processing them concurrently.
113 #define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
116 * Filter definition. This defines the pads a filter contains, and all the
117 * callback functions used to interact with the filter.
119 typedef struct AVFilter {
121 * Filter name. Must be non-NULL and unique among filters.
126 * A description of the filter. May be NULL.
128 * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
130 const char *description;
133 * List of inputs, terminated by a zeroed element.
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
139 const AVFilterPad *inputs;
141 * List of outputs, terminated by a zeroed element.
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
147 const AVFilterPad *outputs;
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.
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.
157 const AVClass *priv_class;
160 * A combination of AVFILTER_FLAG_*
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
168 * New public fields should be added right above.
169 *****************************************************************
173 * Filter initialization function.
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.
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.
184 * This callback must not assume that the filter links exist or frame
185 * parameters are known.
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
191 * @return 0 on success, a negative AVERROR on failure
193 int (*init)(AVFilterContext *ctx);
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.
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).
204 * Otherwise the semantics is the same as for @ref AVFilter.init "init".
206 int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
209 * Filter uninitialization function.
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.
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.
218 void (*uninit)(AVFilterContext *ctx);
221 * Query formats supported by the filter on its inputs and outputs.
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.
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.
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
239 * @return zero on success, a negative value corresponding to an
240 * AVERROR code otherwise
242 int (*query_formats)(AVFilterContext *);
244 int priv_size; ///< size of private data to allocate for the filter
247 * Used by the filter registration system. Must not be touched by any other
250 struct AVFilter *next;
254 * Process multiple parts of the frame concurrently.
256 #define AVFILTER_THREAD_SLICE (1 << 0)
258 typedef struct AVFilterInternal AVFilterInternal;
260 /** An instance of a filter */
261 struct AVFilterContext {
262 const AVClass *av_class; ///< needed for av_log()
264 const AVFilter *filter; ///< the AVFilter of which this is an instance
266 char *name; ///< name of this filter instance
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
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
276 void *priv; ///< private data for use by the filter
278 struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
281 * Type of multithreading being allowed/used. A combination of
282 * AVFILTER_THREAD_* flags.
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
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
293 * After the filter is initialzed, libavfilter sets this field to the
294 * threading type that is actually used (0 for no multithreading).
299 * An opaque struct for libavfilter internal use.
301 AVFilterInternal *internal;
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.
311 struct AVFilterLink {
312 AVFilterContext *src; ///< source filter
313 AVFilterPad *srcpad; ///< output pad on the source filter
315 AVFilterContext *dst; ///< dest filter
316 AVFilterPad *dstpad; ///< input pad on the dest filter
318 enum AVMediaType type; ///< filter media type
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
328 int format; ///< agreed upon media format
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.
337 AVRational time_base;
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
343 * New public fields should be added right above.
344 *****************************************************************
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.
351 AVFilterFormats *in_formats;
352 AVFilterFormats *out_formats;
355 * Lists of channel layouts and sample rates used for automatic
358 AVFilterFormats *in_samplerates;
359 AVFilterFormats *out_samplerates;
360 struct AVFilterChannelLayouts *in_channel_layouts;
361 struct AVFilterChannelLayouts *out_channel_layouts;
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
368 * Last buffer before EOF will be padded with silence.
372 /** stage of the initialization of the link properties (dimensions, etc) */
374 AVLINK_UNINIT = 0, ///< not started
375 AVLINK_STARTINIT, ///< started, but incomplete
376 AVLINK_INIT ///< complete
381 * Link two filters together.
383 * @param src the source filter
384 * @param srcpad index of the output pad on the source filter
385 * @param dst the destination filter
386 * @param dstpad index of the input pad on the destination filter
387 * @return zero on success
389 int avfilter_link(AVFilterContext *src, unsigned srcpad,
390 AVFilterContext *dst, unsigned dstpad);
393 * Negotiate the media format, dimensions, etc of all inputs to a filter.
395 * @param filter the filter to negotiate the properties for its inputs
396 * @return zero on successful negotiation
398 int avfilter_config_links(AVFilterContext *filter);
400 /** Initialize the filter system. Register all builtin filters. */
401 void avfilter_register_all(void);
403 #if FF_API_OLD_FILTER_REGISTER
404 /** Uninitialize the filter system. Unregister all filters. */
406 void avfilter_uninit(void);
410 * Register a filter. This is only needed if you plan to use
411 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
412 * filter can still by instantiated with avfilter_graph_alloc_filter even if it
415 * @param filter the filter to register
416 * @return 0 if the registration was succesfull, a negative value
419 int avfilter_register(AVFilter *filter);
422 * Get a filter definition matching the given name.
424 * @param name the filter name to find
425 * @return the filter definition, if any matching one is registered.
426 * NULL if none found.
428 #if !FF_API_NOCONST_GET_NAME
431 AVFilter *avfilter_get_by_name(const char *name);
434 * Iterate over all registered filters.
435 * @return If prev is non-NULL, next registered filter after prev or NULL if
436 * prev is the last filter. If prev is NULL, return the first registered filter.
438 const AVFilter *avfilter_next(const AVFilter *prev);
440 #if FF_API_OLD_FILTER_REGISTER
442 * If filter is NULL, returns a pointer to the first registered filter pointer,
443 * if filter is non-NULL, returns the next pointer after filter.
444 * If the returned pointer points to NULL, the last registered filter
445 * was already reached.
446 * @deprecated use avfilter_next()
449 AVFilter **av_filter_next(AVFilter **filter);
452 #if FF_API_AVFILTER_OPEN
454 * Create a filter instance.
456 * @param filter_ctx put here a pointer to the created filter context
457 * on success, NULL on failure
458 * @param filter the filter to create an instance of
459 * @param inst_name Name to give to the new instance. Can be NULL for none.
460 * @return >= 0 in case of success, a negative error code otherwise
461 * @deprecated use avfilter_graph_alloc_filter() instead
464 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
468 #if FF_API_AVFILTER_INIT_FILTER
470 * Initialize a filter.
472 * @param filter the filter to initialize
473 * @param args A string of parameters to use when initializing the filter.
474 * The format and meaning of this string varies by filter.
475 * @param opaque Any extra non-string data needed by the filter. The meaning
476 * of this parameter varies by filter.
477 * @return zero on success
480 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
484 * Initialize a filter with the supplied parameters.
486 * @param ctx uninitialized filter context to initialize
487 * @param args Options to initialize the filter with. This must be a
488 * ':'-separated list of options in the 'key=value' form.
489 * May be NULL if the options have been set directly using the
490 * AVOptions API or there are no options that need to be set.
491 * @return 0 on success, a negative AVERROR on failure
493 int avfilter_init_str(AVFilterContext *ctx, const char *args);
496 * Initialize a filter with the supplied dictionary of options.
498 * @param ctx uninitialized filter context to initialize
499 * @param options An AVDictionary filled with options for this filter. On
500 * return this parameter will be destroyed and replaced with
501 * a dict containing options that were not found. This dictionary
502 * must be freed by the caller.
503 * May be NULL, then this function is equivalent to
504 * avfilter_init_str() with the second parameter set to NULL.
505 * @return 0 on success, a negative AVERROR on failure
507 * @note This function and avfilter_init_str() do essentially the same thing,
508 * the difference is in manner in which the options are passed. It is up to the
509 * calling code to choose whichever is more preferable. The two functions also
510 * behave differently when some of the provided options are not declared as
511 * supported by the filter. In such a case, avfilter_init_str() will fail, but
512 * this function will leave those extra options in the options AVDictionary and
515 int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
518 * Free a filter context. This will also remove the filter from its
519 * filtergraph's list of filters.
521 * @param filter the filter to free
523 void avfilter_free(AVFilterContext *filter);
526 * Insert a filter in the middle of an existing link.
528 * @param link the link into which the filter should be inserted
529 * @param filt the filter to be inserted
530 * @param filt_srcpad_idx the input pad on the filter to connect
531 * @param filt_dstpad_idx the output pad on the filter to connect
532 * @return zero on success
534 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
535 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
538 * @return AVClass for AVFilterContext.
540 * @see av_opt_find().
542 const AVClass *avfilter_get_class(void);
544 typedef struct AVFilterGraphInternal AVFilterGraphInternal;
547 * A function pointer passed to the @ref AVFilterGraph.execute callback to be
548 * executed multiple times, possibly in parallel.
550 * @param ctx the filter context the job belongs to
551 * @param arg an opaque parameter passed through from @ref
552 * AVFilterGraph.execute
553 * @param jobnr the index of the job being executed
554 * @param nb_jobs the total number of jobs
556 * @return 0 on success, a negative AVERROR on error
558 typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
561 * A function executing multiple jobs, possibly in parallel.
563 * @param ctx the filter context to which the jobs belong
564 * @param func the function to be called multiple times
565 * @param arg the argument to be passed to func
566 * @param ret a nb_jobs-sized array to be filled with return values from each
568 * @param nb_jobs the number of jobs to execute
570 * @return 0 on success, a negative AVERROR on error
572 typedef int (avfilter_execute_func)(AVFilterContext *ctx, avfilter_action_func *func,
573 void *arg, int *ret, int nb_jobs);
575 typedef struct AVFilterGraph {
576 const AVClass *av_class;
577 AVFilterContext **filters;
580 char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
581 char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
584 * Type of multithreading allowed for filters in this graph. A combination
585 * of AVFILTER_THREAD_* flags.
587 * May be set by the caller at any point, the setting will apply to all
588 * filters initialized after that. The default is allowing everything.
590 * When a filter in this graph is initialized, this field is combined using
591 * bit AND with AVFilterContext.thread_type to get the final mask used for
592 * determining allowed threading types. I.e. a threading type needs to be
593 * set in both to be allowed.
598 * Maximum number of threads used by filters in this graph. May be set by
599 * the caller before adding any filters to the filtergraph. Zero (the
600 * default) means that the number of threads is determined automatically.
605 * Opaque object for libavfilter internal use.
607 AVFilterGraphInternal *internal;
610 * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
611 * be used from callbacks like @ref AVFilterGraph.execute.
612 * Libavfilter will not touch this field in any way.
617 * This callback may be set by the caller immediately after allocating the
618 * graph and before adding any filters to it, to provide a custom
619 * multithreading implementation.
621 * If set, filters with slice threading capability will call this callback
622 * to execute multiple jobs in parallel.
624 * If this field is left unset, libavfilter will use its internal
625 * implementation, which may or may not be multithreaded depending on the
626 * platform and build options.
628 avfilter_execute_func *execute;
632 * Allocate a filter graph.
634 * @return the allocated filter graph on success or NULL.
636 AVFilterGraph *avfilter_graph_alloc(void);
639 * Create a new filter instance in a filter graph.
641 * @param graph graph in which the new filter will be used
642 * @param filter the filter to create an instance of
643 * @param name Name to give to the new instance (will be copied to
644 * AVFilterContext.name). This may be used by the caller to identify
645 * different filters, libavfilter itself assigns no semantics to
646 * this parameter. May be NULL.
648 * @return the context of the newly created filter instance (note that it is
649 * also retrievable directly through AVFilterGraph.filters or with
650 * avfilter_graph_get_filter()) on success or NULL or failure.
652 AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
653 const AVFilter *filter,
657 * Get a filter instance with name name from graph.
659 * @return the pointer to the found filter instance or NULL if it
662 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name);
664 #if FF_API_AVFILTER_OPEN
666 * Add an existing filter instance to a filter graph.
668 * @param graphctx the filter graph
669 * @param filter the filter to be added
671 * @deprecated use avfilter_graph_alloc_filter() to allocate a filter in a
675 int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
679 * Create and add a filter instance into an existing graph.
680 * The filter instance is created from the filter filt and inited
681 * with the parameters args and opaque.
683 * In case of success put in *filt_ctx the pointer to the created
684 * filter instance, otherwise set *filt_ctx to NULL.
686 * @param name the instance name to give to the created filter instance
687 * @param graph_ctx the filter graph
688 * @return a negative AVERROR error code in case of failure, a non
689 * negative value otherwise
691 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
692 const char *name, const char *args, void *opaque,
693 AVFilterGraph *graph_ctx);
696 * Check validity and configure all the links and formats in the graph.
698 * @param graphctx the filter graph
699 * @param log_ctx context used for logging
700 * @return 0 in case of success, a negative AVERROR code otherwise
702 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
705 * Free a graph, destroy its links, and set *graph to NULL.
706 * If *graph is NULL, do nothing.
708 void avfilter_graph_free(AVFilterGraph **graph);
711 * A linked-list of the inputs/outputs of the filter chain.
713 * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
714 * where it is used to communicate open (unlinked) inputs and outputs from and
716 * This struct specifies, per each not connected pad contained in the graph, the
717 * filter context and the pad index required for establishing a link.
719 typedef struct AVFilterInOut {
720 /** unique name for this input/output in the list */
723 /** filter context associated to this input/output */
724 AVFilterContext *filter_ctx;
726 /** index of the filt_ctx pad to use for linking */
729 /** next input/input in the list, NULL if this is the last */
730 struct AVFilterInOut *next;
734 * Allocate a single AVFilterInOut entry.
735 * Must be freed with avfilter_inout_free().
736 * @return allocated AVFilterInOut on success, NULL on failure.
738 AVFilterInOut *avfilter_inout_alloc(void);
741 * Free the supplied list of AVFilterInOut and set *inout to NULL.
742 * If *inout is NULL, do nothing.
744 void avfilter_inout_free(AVFilterInOut **inout);
747 * Add a graph described by a string to a graph.
749 * @param graph the filter graph where to link the parsed graph context
750 * @param filters string to be parsed
751 * @param inputs linked list to the inputs of the graph
752 * @param outputs linked list to the outputs of the graph
753 * @return zero on success, a negative AVERROR code on error
755 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
756 AVFilterInOut *inputs, AVFilterInOut *outputs,
760 * Add a graph described by a string to a graph.
762 * @param[in] graph the filter graph where to link the parsed graph context
763 * @param[in] filters string to be parsed
764 * @param[out] inputs a linked list of all free (unlinked) inputs of the
765 * parsed graph will be returned here. It is to be freed
766 * by the caller using avfilter_inout_free().
767 * @param[out] outputs a linked list of all free (unlinked) outputs of the
768 * parsed graph will be returned here. It is to be freed by the
769 * caller using avfilter_inout_free().
770 * @return zero on success, a negative AVERROR code on error
772 * @note the difference between avfilter_graph_parse2() and
773 * avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
774 * the lists of inputs and outputs, which therefore must be known before calling
775 * the function. On the other hand, avfilter_graph_parse2() \em returns the
776 * inputs and outputs that are left unlinked after parsing the graph and the
777 * caller then deals with them. Another difference is that in
778 * avfilter_graph_parse(), the inputs parameter describes inputs of the
779 * <em>already existing</em> part of the graph; i.e. from the point of view of
780 * the newly created part, they are outputs. Similarly the outputs parameter
781 * describes outputs of the already existing filters, which are provided as
782 * inputs to the parsed filters.
783 * avfilter_graph_parse2() takes the opposite approach -- it makes no reference
784 * whatsoever to already existing parts of the graph and the inputs parameter
785 * will on return contain inputs of the newly parsed part of the graph.
786 * Analogously the outputs parameter will contain outputs of the newly created
789 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
790 AVFilterInOut **inputs,
791 AVFilterInOut **outputs);
797 #endif /* AVFILTER_AVFILTER_H */