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/buffer.h"
39 #include "libavutil/frame.h"
40 #include "libavutil/log.h"
41 #include "libavutil/samplefmt.h"
42 #include "libavutil/pixfmt.h"
43 #include "libavutil/rational.h"
47 #include "libavfilter/version.h"
50 * Return the LIBAVFILTER_VERSION_INT constant.
52 unsigned avfilter_version(void);
55 * Return the libavfilter build-time configuration.
57 const char *avfilter_configuration(void);
60 * Return the libavfilter license.
62 const char *avfilter_license(void);
65 typedef struct AVFilterContext AVFilterContext;
66 typedef struct AVFilterLink AVFilterLink;
67 typedef struct AVFilterPad AVFilterPad;
68 typedef struct AVFilterFormats AVFilterFormats;
71 * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
72 * AVFilter.inputs/outputs).
74 int avfilter_pad_count(const AVFilterPad *pads);
77 * Get the name of an AVFilterPad.
79 * @param pads an array of AVFilterPads
80 * @param pad_idx index of the pad in the array it; is the caller's
81 * responsibility to ensure the index is valid
83 * @return name of the pad_idx'th pad in pads
85 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
88 * Get the type of an AVFilterPad.
90 * @param pads an array of AVFilterPads
91 * @param pad_idx index of the pad in the array; it is the caller's
92 * responsibility to ensure the index is valid
94 * @return type of the pad_idx'th pad in pads
96 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
99 * The number of the filter inputs is not determined just by AVFilter.inputs.
100 * The filter might add additional inputs during initialization depending on the
101 * options supplied to it.
103 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
105 * The number of the filter outputs is not determined just by AVFilter.outputs.
106 * The filter might add additional outputs during initialization depending on
107 * the options supplied to it.
109 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
111 * The filter supports multithreading by splitting frames into multiple parts
112 * and processing them concurrently.
114 #define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
117 * Filter definition. This defines the pads a filter contains, and all the
118 * callback functions used to interact with the filter.
120 typedef struct AVFilter {
122 * Filter name. Must be non-NULL and unique among filters.
127 * A description of the filter. May be NULL.
129 * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
131 const char *description;
134 * List of inputs, terminated by a zeroed element.
136 * NULL if there are no (static) inputs. Instances of filters with
137 * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
140 const AVFilterPad *inputs;
142 * List of outputs, terminated by a zeroed element.
144 * NULL if there are no (static) outputs. Instances of filters with
145 * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
148 const AVFilterPad *outputs;
151 * A class for the private data, used to declare filter private AVOptions.
152 * This field is NULL for filters that do not declare any options.
154 * If this field is non-NULL, the first member of the filter private data
155 * must be a pointer to AVClass, which will be set by libavfilter generic
156 * code to this class.
158 const AVClass *priv_class;
161 * A combination of AVFILTER_FLAG_*
165 /*****************************************************************
166 * All fields below this line are not part of the public API. They
167 * may not be used outside of libavfilter and can be changed and
169 * New public fields should be added right above.
170 *****************************************************************
174 * Filter initialization function.
176 * This callback will be called only once during the filter lifetime, after
177 * all the options have been set, but before links between filters are
178 * established and format negotiation is done.
180 * Basic filter initialization should be done here. Filters with dynamic
181 * inputs and/or outputs should create those inputs/outputs here based on
182 * provided options. No more changes to this filter's inputs/outputs can be
183 * done after this callback.
185 * This callback must not assume that the filter links exist or frame
186 * parameters are known.
188 * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
189 * initialization fails, so this callback does not have to clean up on
192 * @return 0 on success, a negative AVERROR on failure
194 int (*init)(AVFilterContext *ctx);
197 * Should be set instead of @ref AVFilter.init "init" by the filters that
198 * want to pass a dictionary of AVOptions to nested contexts that are
199 * allocated during init.
201 * On return, the options dict should be freed and replaced with one that
202 * contains all the options which could not be processed by this filter (or
203 * with NULL if all the options were processed).
205 * Otherwise the semantics is the same as for @ref AVFilter.init "init".
207 int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
210 * Filter uninitialization function.
212 * Called only once right before the filter is freed. Should deallocate any
213 * memory held by the filter, release any buffer references, etc. It does
214 * not need to deallocate the AVFilterContext.priv memory itself.
216 * This callback may be called even if @ref AVFilter.init "init" was not
217 * called or failed, so it must be prepared to handle such a situation.
219 void (*uninit)(AVFilterContext *ctx);
222 * Query formats supported by the filter on its inputs and outputs.
224 * This callback is called after the filter is initialized (so the inputs
225 * and outputs are fixed), shortly before the format negotiation. This
226 * callback may be called more than once.
228 * This callback must set AVFilterLink.out_formats on every input link and
229 * AVFilterLink.in_formats on every output link to a list of pixel/sample
230 * formats that the filter supports on that link. For audio links, this
231 * filter must also set @ref AVFilterLink.in_samplerates "in_samplerates" /
232 * @ref AVFilterLink.out_samplerates "out_samplerates" and
233 * @ref AVFilterLink.in_channel_layouts "in_channel_layouts" /
234 * @ref AVFilterLink.out_channel_layouts "out_channel_layouts" analogously.
236 * This callback may be NULL for filters with one input, in which case
237 * libavfilter assumes that it supports all input formats and preserves
240 * @return zero on success, a negative value corresponding to an
241 * AVERROR code otherwise
243 int (*query_formats)(AVFilterContext *);
245 int priv_size; ///< size of private data to allocate for the filter
247 int flags_internal; ///< Additional flags for avfilter internal use only.
250 * Used by the filter registration system. Must not be touched by any other
253 struct AVFilter *next;
257 * Process multiple parts of the frame concurrently.
259 #define AVFILTER_THREAD_SLICE (1 << 0)
261 typedef struct AVFilterInternal AVFilterInternal;
263 /** An instance of a filter */
264 struct AVFilterContext {
265 const AVClass *av_class; ///< needed for av_log()
267 const AVFilter *filter; ///< the AVFilter of which this is an instance
269 char *name; ///< name of this filter instance
271 AVFilterPad *input_pads; ///< array of input pads
272 AVFilterLink **inputs; ///< array of pointers to input links
273 unsigned nb_inputs; ///< number of input pads
275 AVFilterPad *output_pads; ///< array of output pads
276 AVFilterLink **outputs; ///< array of pointers to output links
277 unsigned nb_outputs; ///< number of output pads
279 void *priv; ///< private data for use by the filter
281 struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
284 * Type of multithreading being allowed/used. A combination of
285 * AVFILTER_THREAD_* flags.
287 * May be set by the caller before initializing the filter to forbid some
288 * or all kinds of multithreading for this filter. The default is allowing
291 * When the filter is initialized, this field is combined using bit AND with
292 * AVFilterGraph.thread_type to get the final mask used for determining
293 * allowed threading types. I.e. a threading type needs to be set in both
296 * After the filter is initialzed, libavfilter sets this field to the
297 * threading type that is actually used (0 for no multithreading).
302 * An opaque struct for libavfilter internal use.
304 AVFilterInternal *internal;
307 * For filters which will create hardware frames, sets the device the
308 * filter should create them in. All other filters will ignore this field:
309 * in particular, a filter which consumes or processes hardware frames will
310 * instead use the hw_frames_ctx field in AVFilterLink to carry the
311 * hardware context information.
313 AVBufferRef *hw_device_ctx;
316 * Sets the number of extra hardware frames which the filter will
317 * allocate on its output links for use in following filters or by
320 * Some hardware filters require all frames that they will use for
321 * output to be defined in advance before filtering starts. For such
322 * filters, any hardware frame pools used for output must therefore be
323 * of fixed size. The extra frames set here are on top of any number
324 * that the filter needs internally in order to operate normally.
326 * This field must be set before the graph containing this filter is
333 * A link between two filters. This contains pointers to the source and
334 * destination filters between which this link exists, and the indexes of
335 * the pads involved. In addition, this link also contains the parameters
336 * which have been negotiated and agreed upon between the filter, such as
337 * image dimensions, format, etc.
339 struct AVFilterLink {
340 AVFilterContext *src; ///< source filter
341 AVFilterPad *srcpad; ///< output pad on the source filter
343 AVFilterContext *dst; ///< dest filter
344 AVFilterPad *dstpad; ///< input pad on the dest filter
346 enum AVMediaType type; ///< filter media type
348 /* These parameters apply only to video */
349 int w; ///< agreed upon image width
350 int h; ///< agreed upon image height
351 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
352 /* These two parameters apply only to audio */
353 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
354 int sample_rate; ///< samples per second
356 int format; ///< agreed upon media format
359 * Define the time base used by the PTS of the frames/samples
360 * which will pass through this link.
361 * During the configuration stage, each filter is supposed to
362 * change only the output timebase, while the timebase of the
363 * input link is assumed to be an unchangeable property.
365 AVRational time_base;
367 /*****************************************************************
368 * All fields below this line are not part of the public API. They
369 * may not be used outside of libavfilter and can be changed and
371 * New public fields should be added right above.
372 *****************************************************************
375 * Lists of formats supported by the input and output filters respectively.
376 * These lists are used for negotiating the format to actually be used,
377 * which will be loaded into the format member, above, when chosen.
379 AVFilterFormats *in_formats;
380 AVFilterFormats *out_formats;
383 * Lists of channel layouts and sample rates used for automatic
386 AVFilterFormats *in_samplerates;
387 AVFilterFormats *out_samplerates;
388 struct AVFilterChannelLayouts *in_channel_layouts;
389 struct AVFilterChannelLayouts *out_channel_layouts;
392 * Audio only, the destination filter sets this to a non-zero value to
393 * request that buffers with the given number of samples should be sent to
394 * it. AVFilterPad.needs_fifo must also be set on the corresponding input
396 * Last buffer before EOF will be padded with silence.
400 /** stage of the initialization of the link properties (dimensions, etc) */
402 AVLINK_UNINIT = 0, ///< not started
403 AVLINK_STARTINIT, ///< started, but incomplete
404 AVLINK_INIT ///< complete
408 * Frame rate of the stream on the link, or 1/0 if unknown or variable;
409 * if left to 0/0, will be automatically copied from the first input
410 * of the source filter if it exists.
412 * Sources should set it to the real constant frame rate.
413 * If the source frame rate is unknown or variable, set this to 1/0.
414 * Filters should update it if necessary depending on their function.
415 * Sinks can use it to set a default output frame rate.
417 AVRational frame_rate;
420 * For hwaccel pixel formats, this should be a reference to the
421 * AVHWFramesContext describing the frames.
423 AVBufferRef *hw_frames_ctx;
427 * Link two filters together.
429 * @param src the source filter
430 * @param srcpad index of the output pad on the source filter
431 * @param dst the destination filter
432 * @param dstpad index of the input pad on the destination filter
433 * @return zero on success
435 int avfilter_link(AVFilterContext *src, unsigned srcpad,
436 AVFilterContext *dst, unsigned dstpad);
439 * Negotiate the media format, dimensions, etc of all inputs to a filter.
441 * @param filter the filter to negotiate the properties for its inputs
442 * @return zero on successful negotiation
444 int avfilter_config_links(AVFilterContext *filter);
446 /** Initialize the filter system. Register all builtin filters. */
447 void avfilter_register_all(void);
450 * Register a filter. This is only needed if you plan to use
451 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
452 * filter can still by instantiated with avfilter_graph_alloc_filter even if it
455 * @param filter the filter to register
456 * @return 0 if the registration was successful, a negative value
459 int avfilter_register(AVFilter *filter);
462 * Get a filter definition matching the given name.
464 * @param name the filter name to find
465 * @return the filter definition, if any matching one is registered.
466 * NULL if none found.
468 const AVFilter *avfilter_get_by_name(const char *name);
471 * Iterate over all registered filters.
472 * @return If prev is non-NULL, next registered filter after prev or NULL if
473 * prev is the last filter. If prev is NULL, return the first registered filter.
475 const AVFilter *avfilter_next(const AVFilter *prev);
478 * Initialize a filter with the supplied parameters.
480 * @param ctx uninitialized filter context to initialize
481 * @param args Options to initialize the filter with. This must be a
482 * ':'-separated list of options in the 'key=value' form.
483 * May be NULL if the options have been set directly using the
484 * AVOptions API or there are no options that need to be set.
485 * @return 0 on success, a negative AVERROR on failure
487 int avfilter_init_str(AVFilterContext *ctx, const char *args);
490 * Initialize a filter with the supplied dictionary of options.
492 * @param ctx uninitialized filter context to initialize
493 * @param options An AVDictionary filled with options for this filter. On
494 * return this parameter will be destroyed and replaced with
495 * a dict containing options that were not found. This dictionary
496 * must be freed by the caller.
497 * May be NULL, then this function is equivalent to
498 * avfilter_init_str() with the second parameter set to NULL.
499 * @return 0 on success, a negative AVERROR on failure
501 * @note This function and avfilter_init_str() do essentially the same thing,
502 * the difference is in manner in which the options are passed. It is up to the
503 * calling code to choose whichever is more preferable. The two functions also
504 * behave differently when some of the provided options are not declared as
505 * supported by the filter. In such a case, avfilter_init_str() will fail, but
506 * this function will leave those extra options in the options AVDictionary and
509 int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
512 * Free a filter context. This will also remove the filter from its
513 * filtergraph's list of filters.
515 * @param filter the filter to free
517 void avfilter_free(AVFilterContext *filter);
520 * Insert a filter in the middle of an existing link.
522 * @param link the link into which the filter should be inserted
523 * @param filt the filter to be inserted
524 * @param filt_srcpad_idx the input pad on the filter to connect
525 * @param filt_dstpad_idx the output pad on the filter to connect
526 * @return zero on success
528 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
529 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
532 * @return AVClass for AVFilterContext.
534 * @see av_opt_find().
536 const AVClass *avfilter_get_class(void);
538 typedef struct AVFilterGraphInternal AVFilterGraphInternal;
541 * A function pointer passed to the @ref AVFilterGraph.execute callback to be
542 * executed multiple times, possibly in parallel.
544 * @param ctx the filter context the job belongs to
545 * @param arg an opaque parameter passed through from @ref
546 * AVFilterGraph.execute
547 * @param jobnr the index of the job being executed
548 * @param nb_jobs the total number of jobs
550 * @return 0 on success, a negative AVERROR on error
552 typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
555 * A function executing multiple jobs, possibly in parallel.
557 * @param ctx the filter context to which the jobs belong
558 * @param func the function to be called multiple times
559 * @param arg the argument to be passed to func
560 * @param ret a nb_jobs-sized array to be filled with return values from each
562 * @param nb_jobs the number of jobs to execute
564 * @return 0 on success, a negative AVERROR on error
566 typedef int (avfilter_execute_func)(AVFilterContext *ctx, avfilter_action_func *func,
567 void *arg, int *ret, int nb_jobs);
569 typedef struct AVFilterGraph {
570 const AVClass *av_class;
571 AVFilterContext **filters;
574 char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
575 char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
578 * Type of multithreading allowed for filters in this graph. A combination
579 * of AVFILTER_THREAD_* flags.
581 * May be set by the caller at any point, the setting will apply to all
582 * filters initialized after that. The default is allowing everything.
584 * When a filter in this graph is initialized, this field is combined using
585 * bit AND with AVFilterContext.thread_type to get the final mask used for
586 * determining allowed threading types. I.e. a threading type needs to be
587 * set in both to be allowed.
592 * Maximum number of threads used by filters in this graph. May be set by
593 * the caller before adding any filters to the filtergraph. Zero (the
594 * default) means that the number of threads is determined automatically.
599 * Opaque object for libavfilter internal use.
601 AVFilterGraphInternal *internal;
604 * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
605 * be used from callbacks like @ref AVFilterGraph.execute.
606 * Libavfilter will not touch this field in any way.
611 * This callback may be set by the caller immediately after allocating the
612 * graph and before adding any filters to it, to provide a custom
613 * multithreading implementation.
615 * If set, filters with slice threading capability will call this callback
616 * to execute multiple jobs in parallel.
618 * If this field is left unset, libavfilter will use its internal
619 * implementation, which may or may not be multithreaded depending on the
620 * platform and build options.
622 avfilter_execute_func *execute;
626 * Allocate a filter graph.
628 * @return the allocated filter graph on success or NULL.
630 AVFilterGraph *avfilter_graph_alloc(void);
633 * Create a new filter instance in a filter graph.
635 * @param graph graph in which the new filter will be used
636 * @param filter the filter to create an instance of
637 * @param name Name to give to the new instance (will be copied to
638 * AVFilterContext.name). This may be used by the caller to identify
639 * different filters, libavfilter itself assigns no semantics to
640 * this parameter. May be NULL.
642 * @return the context of the newly created filter instance (note that it is
643 * also retrievable directly through AVFilterGraph.filters or with
644 * avfilter_graph_get_filter()) on success or NULL or failure.
646 AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
647 const AVFilter *filter,
651 * Get a filter instance with name name from graph.
653 * @return the pointer to the found filter instance or NULL if it
656 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name);
659 * Create and add a filter instance into an existing graph.
660 * The filter instance is created from the filter filt and inited
661 * with the parameters args and opaque.
663 * In case of success put in *filt_ctx the pointer to the created
664 * filter instance, otherwise set *filt_ctx to NULL.
666 * @param name the instance name to give to the created filter instance
667 * @param graph_ctx the filter graph
668 * @return a negative AVERROR error code in case of failure, a non
669 * negative value otherwise
671 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
672 const char *name, const char *args, void *opaque,
673 AVFilterGraph *graph_ctx);
676 * Check validity and configure all the links and formats in the graph.
678 * @param graphctx the filter graph
679 * @param log_ctx context used for logging
680 * @return 0 in case of success, a negative AVERROR code otherwise
682 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
685 * Free a graph, destroy its links, and set *graph to NULL.
686 * If *graph is NULL, do nothing.
688 void avfilter_graph_free(AVFilterGraph **graph);
691 * A linked-list of the inputs/outputs of the filter chain.
693 * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
694 * where it is used to communicate open (unlinked) inputs and outputs from and
696 * This struct specifies, per each not connected pad contained in the graph, the
697 * filter context and the pad index required for establishing a link.
699 typedef struct AVFilterInOut {
700 /** unique name for this input/output in the list */
703 /** filter context associated to this input/output */
704 AVFilterContext *filter_ctx;
706 /** index of the filt_ctx pad to use for linking */
709 /** next input/input in the list, NULL if this is the last */
710 struct AVFilterInOut *next;
714 * Allocate a single AVFilterInOut entry.
715 * Must be freed with avfilter_inout_free().
716 * @return allocated AVFilterInOut on success, NULL on failure.
718 AVFilterInOut *avfilter_inout_alloc(void);
721 * Free the supplied list of AVFilterInOut and set *inout to NULL.
722 * If *inout is NULL, do nothing.
724 void avfilter_inout_free(AVFilterInOut **inout);
727 * Add a graph described by a string to a graph.
729 * @param graph the filter graph where to link the parsed graph context
730 * @param filters string to be parsed
731 * @param inputs linked list to the inputs of the graph
732 * @param outputs linked list to the outputs of the graph
733 * @return zero on success, a negative AVERROR code on error
735 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
736 AVFilterInOut *inputs, AVFilterInOut *outputs,
740 * Add a graph described by a string to a graph.
742 * @param[in] graph the filter graph where to link the parsed graph context
743 * @param[in] filters string to be parsed
744 * @param[out] inputs a linked list of all free (unlinked) inputs of the
745 * parsed graph will be returned here. It is to be freed
746 * by the caller using avfilter_inout_free().
747 * @param[out] outputs a linked list of all free (unlinked) outputs of the
748 * parsed graph will be returned here. It is to be freed by the
749 * caller using avfilter_inout_free().
750 * @return zero on success, a negative AVERROR code on error
752 * @note the difference between avfilter_graph_parse2() and
753 * avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
754 * the lists of inputs and outputs, which therefore must be known before calling
755 * the function. On the other hand, avfilter_graph_parse2() \em returns the
756 * inputs and outputs that are left unlinked after parsing the graph and the
757 * caller then deals with them. Another difference is that in
758 * avfilter_graph_parse(), the inputs parameter describes inputs of the
759 * <em>already existing</em> part of the graph; i.e. from the point of view of
760 * the newly created part, they are outputs. Similarly the outputs parameter
761 * describes outputs of the already existing filters, which are provided as
762 * inputs to the parsed filters.
763 * avfilter_graph_parse2() takes the opposite approach -- it makes no reference
764 * whatsoever to already existing parts of the graph and the inputs parameter
765 * will on return contain inputs of the newly parsed part of the graph.
766 * Analogously the outputs parameter will contain outputs of the newly created
769 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
770 AVFilterInOut **inputs,
771 AVFilterInOut **outputs);
777 #endif /* AVFILTER_AVFILTER_H */