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
25 #include "libavutil/avutil.h"
26 #include "libavutil/frame.h"
27 #include "libavutil/log.h"
28 #include "libavutil/samplefmt.h"
29 #include "libavutil/pixfmt.h"
30 #include "libavutil/rational.h"
31 #include "libavcodec/avcodec.h"
35 #include "libavfilter/version.h"
38 * Return the LIBAVFILTER_VERSION_INT constant.
40 unsigned avfilter_version(void);
43 * Return the libavfilter build-time configuration.
45 const char *avfilter_configuration(void);
48 * Return the libavfilter license.
50 const char *avfilter_license(void);
53 typedef struct AVFilterContext AVFilterContext;
54 typedef struct AVFilterLink AVFilterLink;
55 typedef struct AVFilterPad AVFilterPad;
56 typedef struct AVFilterFormats AVFilterFormats;
58 #if FF_API_AVFILTERBUFFER
60 * A reference-counted buffer data type used by the filter system. Filters
61 * should not store pointers to this structure directly, but instead use the
62 * AVFilterBufferRef structure below.
64 typedef struct AVFilterBuffer {
65 uint8_t *data[8]; ///< buffer data for each plane/channel
68 * pointers to the data planes/channels.
70 * For video, this should simply point to data[].
72 * For planar audio, each channel has a separate data pointer, and
73 * linesize[0] contains the size of each channel buffer.
74 * For packed audio, there is just one data pointer, and linesize[0]
75 * contains the total size of the buffer for all channels.
77 * Note: Both data and extended_data will always be set, but for planar
78 * audio with more channels that can fit in data, extended_data must be used
79 * in order to access all channels.
81 uint8_t **extended_data;
82 int linesize[8]; ///< number of bytes per line
84 /** private data to be used by a custom free function */
87 * A pointer to the function to deallocate this buffer if the default
88 * function is not sufficient. This could, for example, add the memory
89 * back into a memory pool to be reused later without the overhead of
90 * reallocating it from scratch.
92 void (*free)(struct AVFilterBuffer *buf);
94 int format; ///< media format
95 int w, h; ///< width and height of the allocated buffer
96 unsigned refcount; ///< number of references to this buffer
99 #define AV_PERM_READ 0x01 ///< can read from the buffer
100 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
101 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
102 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
103 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
104 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
107 * Audio specific properties in a reference to an AVFilterBuffer. Since
108 * AVFilterBufferRef is common to different media formats, audio specific
109 * per reference properties must be separated out.
111 typedef struct AVFilterBufferRefAudioProps {
112 uint64_t channel_layout; ///< channel layout of audio buffer
113 int nb_samples; ///< number of audio samples
114 int sample_rate; ///< audio buffer sample rate
115 int planar; ///< audio buffer - planar or packed
116 } AVFilterBufferRefAudioProps;
119 * Video specific properties in a reference to an AVFilterBuffer. Since
120 * AVFilterBufferRef is common to different media formats, video specific
121 * per reference properties must be separated out.
123 typedef struct AVFilterBufferRefVideoProps {
124 int w; ///< image width
125 int h; ///< image height
126 AVRational pixel_aspect; ///< pixel aspect ratio
127 int interlaced; ///< is frame interlaced
128 int top_field_first; ///< field order
129 enum AVPictureType pict_type; ///< picture type of the frame
130 int key_frame; ///< 1 -> keyframe, 0-> not
131 } AVFilterBufferRefVideoProps;
134 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
135 * a buffer to, for example, crop image without any memcpy, the buffer origin
136 * and dimensions are per-reference properties. Linesize is also useful for
137 * image flipping, frame to field filters, etc, and so is also per-reference.
139 * TODO: add anything necessary for frame reordering
141 typedef struct AVFilterBufferRef {
142 AVFilterBuffer *buf; ///< the buffer that this is a reference to
143 uint8_t *data[8]; ///< picture/audio data for each plane
145 * pointers to the data planes/channels.
147 * For video, this should simply point to data[].
149 * For planar audio, each channel has a separate data pointer, and
150 * linesize[0] contains the size of each channel buffer.
151 * For packed audio, there is just one data pointer, and linesize[0]
152 * contains the total size of the buffer for all channels.
154 * Note: Both data and extended_data will always be set, but for planar
155 * audio with more channels that can fit in data, extended_data must be used
156 * in order to access all channels.
158 uint8_t **extended_data;
159 int linesize[8]; ///< number of bytes per line
161 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
162 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
165 * presentation timestamp. The time unit may change during
166 * filtering, as it is specified in the link and the filter code
167 * may need to rescale the PTS accordingly.
170 int64_t pos; ///< byte position in stream, -1 if unknown
172 int format; ///< media format
174 int perms; ///< permissions, see the AV_PERM_* flags
176 enum AVMediaType type; ///< media type of buffer data
180 * Copy properties of src to dst, without copying the actual data
183 void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src);
186 * Add a new reference to a buffer.
188 * @param ref an existing reference to the buffer
189 * @param pmask a bitmask containing the allowable permissions in the new
191 * @return a new reference to the buffer with the same properties as the
192 * old, excluding any permissions denied by pmask
195 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
198 * Remove a reference to a buffer. If this is the last reference to the
199 * buffer, the buffer itself is also automatically freed.
201 * @param ref reference to the buffer, may be NULL
203 * @note it is recommended to use avfilter_unref_bufferp() instead of this
207 void avfilter_unref_buffer(AVFilterBufferRef *ref);
210 * Remove a reference to a buffer and set the pointer to NULL.
211 * If this is the last reference to the buffer, the buffer itself
212 * is also automatically freed.
214 * @param ref pointer to the buffer reference
217 void avfilter_unref_bufferp(AVFilterBufferRef **ref);
220 #if FF_API_AVFILTERPAD_PUBLIC
222 * A filter pad used for either input or output.
224 * @warning this struct will be removed from public API.
225 * users should call avfilter_pad_get_name() and avfilter_pad_get_type()
226 * to access the name and type fields; there should be no need to access
227 * any other fields from outside of libavfilter.
231 * Pad name. The name is unique among inputs and among outputs, but an
232 * input may have the same name as an output. This may be NULL if this
233 * pad has no need to ever be referenced by name.
240 enum AVMediaType type;
243 * Minimum required permissions on incoming buffers. Any buffer with
244 * insufficient permissions will be automatically copied by the filter
245 * system to a new buffer which provides the needed access permissions.
249 attribute_deprecated int min_perms;
252 * Permissions which are not accepted on incoming buffers. Any buffer
253 * which has any of these permissions set will be automatically copied
254 * by the filter system to a new buffer which does not have those
255 * permissions. This can be used to easily disallow buffers with
260 attribute_deprecated int rej_perms;
265 int (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
268 * Callback function to get a video buffer. If NULL, the filter system will
269 * use avfilter_default_get_video_buffer().
271 * Input video pads only.
273 AVFrame *(*get_video_buffer)(AVFilterLink *link, int w, int h);
276 * Callback function to get an audio buffer. If NULL, the filter system will
277 * use avfilter_default_get_audio_buffer().
279 * Input audio pads only.
281 AVFrame *(*get_audio_buffer)(AVFilterLink *link, int nb_samples);
286 int (*end_frame)(AVFilterLink *link);
291 int (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
294 * Filtering callback. This is where a filter receives a frame with
295 * audio/video data and should do its processing.
299 * @return >= 0 on success, a negative AVERROR on error. This function
300 * must ensure that samplesref is properly unreferenced on error if it
301 * hasn't been passed on to another filter.
303 int (*filter_frame)(AVFilterLink *link, AVFrame *frame);
306 * Frame poll callback. This returns the number of immediately available
307 * samples. It should return a positive value if the next request_frame()
308 * is guaranteed to return one frame (with no delay).
310 * Defaults to just calling the source poll_frame() method.
314 int (*poll_frame)(AVFilterLink *link);
317 * Frame request callback. A call to this should result in at least one
318 * frame being output over the given link. This should return zero on
319 * success, and another value on error.
323 int (*request_frame)(AVFilterLink *link);
326 * Link configuration callback.
328 * For output pads, this should set the link properties such as
329 * width/height. This should NOT set the format property - that is
330 * negotiated between filters by the filter system using the
331 * query_formats() callback before this function is called.
333 * For input pads, this should check the properties of the link, and update
334 * the filter's internal state as necessary.
336 * For both input and output filters, this should return zero on success,
337 * and another value on error.
339 int (*config_props)(AVFilterLink *link);
342 * The filter expects a fifo to be inserted on its input link,
343 * typically because it has a delay.
354 * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
355 * AVFilter.inputs/outputs).
357 int avfilter_pad_count(const AVFilterPad *pads);
360 * Get the name of an AVFilterPad.
362 * @param pads an array of AVFilterPads
363 * @param pad_idx index of the pad in the array it; is the caller's
364 * responsibility to ensure the index is valid
366 * @return name of the pad_idx'th pad in pads
368 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
371 * Get the type of an AVFilterPad.
373 * @param pads an array of AVFilterPads
374 * @param pad_idx index of the pad in the array; it is the caller's
375 * responsibility to ensure the index is valid
377 * @return type of the pad_idx'th pad in pads
379 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
382 * The number of the filter inputs is not determined just by AVFilter.inputs.
383 * The filter might add additional inputs during initialization depending on the
384 * options supplied to it.
386 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
388 * The number of the filter outputs is not determined just by AVFilter.outputs.
389 * The filter might add additional outputs during initialization depending on
390 * the options supplied to it.
392 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
395 * Filter definition. This defines the pads a filter contains, and all the
396 * callback functions used to interact with the filter.
398 typedef struct AVFilter {
399 const char *name; ///< filter name
402 * A description for the filter. You should use the
403 * NULL_IF_CONFIG_SMALL() macro to define it.
405 const char *description;
407 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
408 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
411 * A class for the private data, used to access filter private
414 const AVClass *priv_class;
417 * A combination of AVFILTER_FLAG_*
421 /*****************************************************************
422 * All fields below this line are not part of the public API. They
423 * may not be used outside of libavfilter and can be changed and
425 * New public fields should be added right above.
426 *****************************************************************
430 * Filter initialization function. Called when all the options have been
433 int (*init)(AVFilterContext *ctx);
436 * Should be set instead of init by the filters that want to pass a
437 * dictionary of AVOptions to nested contexts that are allocated in
440 int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
443 * Filter uninitialization function. Should deallocate any memory held
444 * by the filter, release any buffer references, etc. This does not need
445 * to deallocate the AVFilterContext->priv memory itself.
447 void (*uninit)(AVFilterContext *ctx);
450 * Queries formats supported by the filter and its pads, and sets the
451 * in_formats for links connected to its output pads, and out_formats
452 * for links connected to its input pads.
454 * @return zero on success, a negative value corresponding to an
455 * AVERROR code otherwise
457 int (*query_formats)(AVFilterContext *);
459 int priv_size; ///< size of private data to allocate for the filter
461 struct AVFilter *next;
464 /** An instance of a filter */
465 struct AVFilterContext {
466 const AVClass *av_class; ///< needed for av_log()
468 const AVFilter *filter; ///< the AVFilter of which this is an instance
470 char *name; ///< name of this filter instance
472 AVFilterPad *input_pads; ///< array of input pads
473 AVFilterLink **inputs; ///< array of pointers to input links
475 unsigned input_count; ///< @deprecated use nb_inputs
477 unsigned nb_inputs; ///< number of input pads
479 AVFilterPad *output_pads; ///< array of output pads
480 AVFilterLink **outputs; ///< array of pointers to output links
482 unsigned output_count; ///< @deprecated use nb_outputs
484 unsigned nb_outputs; ///< number of output pads
486 void *priv; ///< private data for use by the filter
488 struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
492 * A link between two filters. This contains pointers to the source and
493 * destination filters between which this link exists, and the indexes of
494 * the pads involved. In addition, this link also contains the parameters
495 * which have been negotiated and agreed upon between the filter, such as
496 * image dimensions, format, etc.
498 struct AVFilterLink {
499 AVFilterContext *src; ///< source filter
500 AVFilterPad *srcpad; ///< output pad on the source filter
502 AVFilterContext *dst; ///< dest filter
503 AVFilterPad *dstpad; ///< input pad on the dest filter
505 enum AVMediaType type; ///< filter media type
507 /* These parameters apply only to video */
508 int w; ///< agreed upon image width
509 int h; ///< agreed upon image height
510 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
511 /* These two parameters apply only to audio */
512 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
513 int sample_rate; ///< samples per second
515 int format; ///< agreed upon media format
518 * Define the time base used by the PTS of the frames/samples
519 * which will pass through this link.
520 * During the configuration stage, each filter is supposed to
521 * change only the output timebase, while the timebase of the
522 * input link is assumed to be an unchangeable property.
524 AVRational time_base;
526 /*****************************************************************
527 * All fields below this line are not part of the public API. They
528 * may not be used outside of libavfilter and can be changed and
530 * New public fields should be added right above.
531 *****************************************************************
534 * Lists of formats supported by the input and output filters respectively.
535 * These lists are used for negotiating the format to actually be used,
536 * which will be loaded into the format member, above, when chosen.
538 AVFilterFormats *in_formats;
539 AVFilterFormats *out_formats;
542 * Lists of channel layouts and sample rates used for automatic
545 AVFilterFormats *in_samplerates;
546 AVFilterFormats *out_samplerates;
547 struct AVFilterChannelLayouts *in_channel_layouts;
548 struct AVFilterChannelLayouts *out_channel_layouts;
551 * Audio only, the destination filter sets this to a non-zero value to
552 * request that buffers with the given number of samples should be sent to
553 * it. AVFilterPad.needs_fifo must also be set on the corresponding input
555 * Last buffer before EOF will be padded with silence.
559 /** stage of the initialization of the link properties (dimensions, etc) */
561 AVLINK_UNINIT = 0, ///< not started
562 AVLINK_STARTINIT, ///< started, but incomplete
563 AVLINK_INIT ///< complete
568 * Link two filters together.
570 * @param src the source filter
571 * @param srcpad index of the output pad on the source filter
572 * @param dst the destination filter
573 * @param dstpad index of the input pad on the destination filter
574 * @return zero on success
576 int avfilter_link(AVFilterContext *src, unsigned srcpad,
577 AVFilterContext *dst, unsigned dstpad);
580 * Negotiate the media format, dimensions, etc of all inputs to a filter.
582 * @param filter the filter to negotiate the properties for its inputs
583 * @return zero on successful negotiation
585 int avfilter_config_links(AVFilterContext *filter);
587 #if FF_API_AVFILTERBUFFER
589 * Create a buffer reference wrapped around an already allocated image
592 * @param data pointers to the planes of the image to reference
593 * @param linesize linesizes for the planes of the image to reference
594 * @param perms the required access permissions
595 * @param w the width of the image specified by the data and linesize arrays
596 * @param h the height of the image specified by the data and linesize arrays
597 * @param format the pixel format of the image specified by the data and linesize arrays
601 avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int perms,
602 int w, int h, enum AVPixelFormat format);
605 * Create an audio buffer reference wrapped around an already
606 * allocated samples buffer.
608 * @param data pointers to the samples plane buffers
609 * @param linesize linesize for the samples plane buffers
610 * @param perms the required access permissions
611 * @param nb_samples number of samples per channel
612 * @param sample_fmt the format of each sample in the buffer to allocate
613 * @param channel_layout the channel layout of the buffer
616 AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
620 enum AVSampleFormat sample_fmt,
621 uint64_t channel_layout);
624 /** Initialize the filter system. Register all builtin filters. */
625 void avfilter_register_all(void);
627 #if FF_API_OLD_FILTER_REGISTER
628 /** Uninitialize the filter system. Unregister all filters. */
630 void avfilter_uninit(void);
634 * Register a filter. This is only needed if you plan to use
635 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
636 * filter can still by instantiated with avfilter_graph_alloc_filter even if it
639 * @param filter the filter to register
640 * @return 0 if the registration was succesfull, a negative value
643 int avfilter_register(AVFilter *filter);
646 * Get a filter definition matching the given name.
648 * @param name the filter name to find
649 * @return the filter definition, if any matching one is registered.
650 * NULL if none found.
652 AVFilter *avfilter_get_by_name(const char *name);
655 * Iterate over all registered filters.
656 * @return If prev is non-NULL, next registered filter after prev or NULL if
657 * prev is the last filter. If prev is NULL, return the first registered filter.
659 const AVFilter *avfilter_next(const AVFilter *prev);
661 #if FF_API_OLD_FILTER_REGISTER
663 * If filter is NULL, returns a pointer to the first registered filter pointer,
664 * if filter is non-NULL, returns the next pointer after filter.
665 * If the returned pointer points to NULL, the last registered filter
666 * was already reached.
667 * @deprecated use avfilter_next()
670 AVFilter **av_filter_next(AVFilter **filter);
673 #if FF_API_AVFILTER_OPEN
675 * Create a filter instance.
677 * @param filter_ctx put here a pointer to the created filter context
678 * on success, NULL on failure
679 * @param filter the filter to create an instance of
680 * @param inst_name Name to give to the new instance. Can be NULL for none.
681 * @return >= 0 in case of success, a negative error code otherwise
682 * @deprecated use avfilter_graph_alloc_filter() instead
685 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
689 #if FF_API_AVFILTER_INIT_FILTER
691 * Initialize a filter.
693 * @param filter the filter to initialize
694 * @param args A string of parameters to use when initializing the filter.
695 * The format and meaning of this string varies by filter.
696 * @param opaque Any extra non-string data needed by the filter. The meaning
697 * of this parameter varies by filter.
698 * @return zero on success
701 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
705 * Initialize a filter with the supplied parameters.
707 * @param ctx uninitialized filter context to initialize
708 * @param args Options to initialize the filter with. This must be a
709 * ':'-separated list of options in the 'key=value' form.
710 * May be NULL if the options have been set directly using the
711 * AVOptions API or there are no options that need to be set.
712 * @return 0 on success, a negative AVERROR on failure
714 int avfilter_init_str(AVFilterContext *ctx, const char *args);
717 * Initialize a filter with the supplied dictionary of options.
719 * @param ctx uninitialized filter context to initialize
720 * @param options An AVDictionary filled with options for this filter. On
721 * return this parameter will be destroyed and replaced with
722 * a dict containing options that were not found. This dictionary
723 * must be freed by the caller.
724 * May be NULL, then this function is equivalent to
725 * avfilter_init_str() with the second parameter set to NULL.
726 * @return 0 on success, a negative AVERROR on failure
728 * @note This function and avfilter_init_str() do essentially the same thing,
729 * the difference is in manner in which the options are passed. It is up to the
730 * calling code to choose whichever is more preferable. The two functions also
731 * behave differently when some of the provided options are not declared as
732 * supported by the filter. In such a case, avfilter_init_str() will fail, but
733 * this function will leave those extra options in the options AVDictionary and
736 int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
739 * Free a filter context. This will also remove the filter from its
740 * filtergraph's list of filters.
742 * @param filter the filter to free
744 void avfilter_free(AVFilterContext *filter);
747 * Insert a filter in the middle of an existing link.
749 * @param link the link into which the filter should be inserted
750 * @param filt the filter to be inserted
751 * @param filt_srcpad_idx the input pad on the filter to connect
752 * @param filt_dstpad_idx the output pad on the filter to connect
753 * @return zero on success
755 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
756 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
758 #if FF_API_AVFILTERBUFFER
760 * Copy the frame properties of src to dst, without copying the actual
763 * @return 0 on success, a negative number on error.
766 int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
769 * Copy the frame properties and data pointers of src to dst, without copying
772 * @return 0 on success, a negative number on error.
775 int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src);
779 * @return AVClass for AVFilterContext.
781 * @see av_opt_find().
783 const AVClass *avfilter_get_class(void);
785 typedef struct AVFilterGraph {
786 const AVClass *av_class;
789 unsigned filter_count;
791 AVFilterContext **filters;
792 #if !FF_API_FOO_COUNT
796 char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
797 char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
804 * Allocate a filter graph.
806 AVFilterGraph *avfilter_graph_alloc(void);
809 * Create a new filter instance in a filter graph.
811 * @param graph graph in which the new filter will be used
812 * @param filter the filter to create an instance of
813 * @param name Name to give to the new instance (will be copied to
814 * AVFilterContext.name). This may be used by the caller to identify
815 * different filters, libavfilter itself assigns no semantics to
816 * this parameter. May be NULL.
818 * @return the context of the newly created filter instance (note that it is
819 * also retrievable directly through AVFilterGraph.filters or with
820 * avfilter_graph_get_filter()) on success or NULL or failure.
822 AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
823 const AVFilter *filter,
827 * Get a filter instance with name name from graph.
829 * @return the pointer to the found filter instance or NULL if it
832 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name);
834 #if FF_API_AVFILTER_OPEN
836 * Add an existing filter instance to a filter graph.
838 * @param graphctx the filter graph
839 * @param filter the filter to be added
841 * @deprecated use avfilter_graph_alloc_filter() to allocate a filter in a
845 int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
849 * Create and add a filter instance into an existing graph.
850 * The filter instance is created from the filter filt and inited
851 * with the parameters args and opaque.
853 * In case of success put in *filt_ctx the pointer to the created
854 * filter instance, otherwise set *filt_ctx to NULL.
856 * @param name the instance name to give to the created filter instance
857 * @param graph_ctx the filter graph
858 * @return a negative AVERROR error code in case of failure, a non
859 * negative value otherwise
861 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, AVFilter *filt,
862 const char *name, const char *args, void *opaque,
863 AVFilterGraph *graph_ctx);
866 * Check validity and configure all the links and formats in the graph.
868 * @param graphctx the filter graph
869 * @param log_ctx context used for logging
870 * @return 0 in case of success, a negative AVERROR code otherwise
872 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
875 * Free a graph, destroy its links, and set *graph to NULL.
876 * If *graph is NULL, do nothing.
878 void avfilter_graph_free(AVFilterGraph **graph);
881 * A linked-list of the inputs/outputs of the filter chain.
883 * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
884 * where it is used to communicate open (unlinked) inputs and outputs from and
886 * This struct specifies, per each not connected pad contained in the graph, the
887 * filter context and the pad index required for establishing a link.
889 typedef struct AVFilterInOut {
890 /** unique name for this input/output in the list */
893 /** filter context associated to this input/output */
894 AVFilterContext *filter_ctx;
896 /** index of the filt_ctx pad to use for linking */
899 /** next input/input in the list, NULL if this is the last */
900 struct AVFilterInOut *next;
904 * Allocate a single AVFilterInOut entry.
905 * Must be freed with avfilter_inout_free().
906 * @return allocated AVFilterInOut on success, NULL on failure.
908 AVFilterInOut *avfilter_inout_alloc(void);
911 * Free the supplied list of AVFilterInOut and set *inout to NULL.
912 * If *inout is NULL, do nothing.
914 void avfilter_inout_free(AVFilterInOut **inout);
917 * Add a graph described by a string to a graph.
919 * @param graph the filter graph where to link the parsed graph context
920 * @param filters string to be parsed
921 * @param inputs linked list to the inputs of the graph
922 * @param outputs linked list to the outputs of the graph
923 * @return zero on success, a negative AVERROR code on error
925 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
926 AVFilterInOut *inputs, AVFilterInOut *outputs,
930 * Add a graph described by a string to a graph.
932 * @param[in] graph the filter graph where to link the parsed graph context
933 * @param[in] filters string to be parsed
934 * @param[out] inputs a linked list of all free (unlinked) inputs of the
935 * parsed graph will be returned here. It is to be freed
936 * by the caller using avfilter_inout_free().
937 * @param[out] outputs a linked list of all free (unlinked) outputs of the
938 * parsed graph will be returned here. It is to be freed by the
939 * caller using avfilter_inout_free().
940 * @return zero on success, a negative AVERROR code on error
942 * @note the difference between avfilter_graph_parse2() and
943 * avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
944 * the lists of inputs and outputs, which therefore must be known before calling
945 * the function. On the other hand, avfilter_graph_parse2() \em returns the
946 * inputs and outputs that are left unlinked after parsing the graph and the
947 * caller then deals with them. Another difference is that in
948 * avfilter_graph_parse(), the inputs parameter describes inputs of the
949 * <em>already existing</em> part of the graph; i.e. from the point of view of
950 * the newly created part, they are outputs. Similarly the outputs parameter
951 * describes outputs of the already existing filters, which are provided as
952 * inputs to the parsed filters.
953 * avfilter_graph_parse2() takes the opposite approach -- it makes no reference
954 * whatsoever to already existing parts of the graph and the inputs parameter
955 * will on return contain inputs of the newly parsed part of the graph.
956 * Analogously the outputs parameter will contain outputs of the newly created
959 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
960 AVFilterInOut **inputs,
961 AVFilterInOut **outputs);
963 #endif /* AVFILTER_AVFILTER_H */