3 * Copyright (c) 2007 Bobby Bingham
5 * This file is part of FFmpeg.
7 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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
27 #include "libavutil/avutil.h"
28 #include "libavutil/dict.h"
29 #include "libavutil/log.h"
30 #include "libavutil/samplefmt.h"
31 #include "libavutil/pixfmt.h"
32 #include "libavutil/rational.h"
34 #include "libavfilter/version.h"
37 * Return the LIBAVFILTER_VERSION_INT constant.
39 unsigned avfilter_version(void);
42 * Return the libavfilter build-time configuration.
44 const char *avfilter_configuration(void);
47 * Return the libavfilter license.
49 const char *avfilter_license(void);
52 * Get the class for the AVFilterContext struct.
54 const AVClass *avfilter_get_class(void);
56 typedef struct AVFilterContext AVFilterContext;
57 typedef struct AVFilterLink AVFilterLink;
58 typedef struct AVFilterPad AVFilterPad;
59 typedef struct AVFilterFormats AVFilterFormats;
62 * A reference-counted buffer data type used by the filter system. Filters
63 * should not store pointers to this structure directly, but instead use the
64 * AVFilterBufferRef structure below.
66 typedef struct AVFilterBuffer {
67 uint8_t *data[8]; ///< buffer data for each plane/channel
70 * pointers to the data planes/channels.
72 * For video, this should simply point to data[].
74 * For planar audio, each channel has a separate data pointer, and
75 * linesize[0] contains the size of each channel buffer.
76 * For packed audio, there is just one data pointer, and linesize[0]
77 * contains the total size of the buffer for all channels.
79 * Note: Both data and extended_data will always be set, but for planar
80 * audio with more channels that can fit in data, extended_data must be used
81 * in order to access all channels.
83 uint8_t **extended_data;
84 int linesize[8]; ///< number of bytes per line
86 /** private data to be used by a custom free function */
89 * A pointer to the function to deallocate this buffer if the default
90 * function is not sufficient. This could, for example, add the memory
91 * back into a memory pool to be reused later without the overhead of
92 * reallocating it from scratch.
94 void (*free)(struct AVFilterBuffer *buf);
96 int format; ///< media format
97 int w, h; ///< width and height of the allocated buffer
98 unsigned refcount; ///< number of references to this buffer
101 #define AV_PERM_READ 0x01 ///< can read from the buffer
102 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
103 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
104 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
105 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
106 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
107 #define AV_PERM_ALIGN 0x40 ///< the buffer must be aligned
109 #define AVFILTER_ALIGN 16 //not part of ABI
112 * Audio specific properties in a reference to an AVFilterBuffer. Since
113 * AVFilterBufferRef is common to different media formats, audio specific
114 * per reference properties must be separated out.
116 typedef struct AVFilterBufferRefAudioProps {
117 uint64_t channel_layout; ///< channel layout of audio buffer
118 int nb_samples; ///< number of audio samples per channel
119 int sample_rate; ///< audio buffer sample rate
120 int channels; ///< number of channels
121 } AVFilterBufferRefAudioProps;
124 * Video specific properties in a reference to an AVFilterBuffer. Since
125 * AVFilterBufferRef is common to different media formats, video specific
126 * per reference properties must be separated out.
128 typedef struct AVFilterBufferRefVideoProps {
129 int w; ///< image width
130 int h; ///< image height
131 AVRational sample_aspect_ratio; ///< sample aspect ratio
132 int interlaced; ///< is frame interlaced
133 int top_field_first; ///< field order
134 enum AVPictureType pict_type; ///< picture type of the frame
135 int key_frame; ///< 1 -> keyframe, 0-> not
136 int qp_table_linesize; ///< qp_table stride
137 int qp_table_size; ///< qp_table size
138 int8_t *qp_table; ///< array of Quantization Parameters
139 } AVFilterBufferRefVideoProps;
142 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
143 * a buffer to, for example, crop image without any memcpy, the buffer origin
144 * and dimensions are per-reference properties. Linesize is also useful for
145 * image flipping, frame to field filters, etc, and so is also per-reference.
147 * TODO: add anything necessary for frame reordering
149 typedef struct AVFilterBufferRef {
150 AVFilterBuffer *buf; ///< the buffer that this is a reference to
151 uint8_t *data[8]; ///< picture/audio data for each plane
153 * pointers to the data planes/channels.
155 * For video, this should simply point to data[].
157 * For planar audio, each channel has a separate data pointer, and
158 * linesize[0] contains the size of each channel buffer.
159 * For packed audio, there is just one data pointer, and linesize[0]
160 * contains the total size of the buffer for all channels.
162 * Note: Both data and extended_data will always be set, but for planar
163 * audio with more channels that can fit in data, extended_data must be used
164 * in order to access all channels.
166 uint8_t **extended_data;
167 int linesize[8]; ///< number of bytes per line
169 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
170 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
173 * presentation timestamp. The time unit may change during
174 * filtering, as it is specified in the link and the filter code
175 * may need to rescale the PTS accordingly.
178 int64_t pos; ///< byte position in stream, -1 if unknown
180 int format; ///< media format
182 int perms; ///< permissions, see the AV_PERM_* flags
184 enum AVMediaType type; ///< media type of buffer data
186 AVDictionary *metadata; ///< dictionary containing metadata key=value tags
190 * Copy properties of src to dst, without copying the actual data
192 void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src);
195 * Add a new reference to a buffer.
197 * @param ref an existing reference to the buffer
198 * @param pmask a bitmask containing the allowable permissions in the new
200 * @return a new reference to the buffer with the same properties as the
201 * old, excluding any permissions denied by pmask
203 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
206 * Remove a reference to a buffer. If this is the last reference to the
207 * buffer, the buffer itself is also automatically freed.
209 * @param ref reference to the buffer, may be NULL
211 * @note it is recommended to use avfilter_unref_bufferp() instead of this
214 void avfilter_unref_buffer(AVFilterBufferRef *ref);
217 * Remove a reference to a buffer and set the pointer to NULL.
218 * If this is the last reference to the buffer, the buffer itself
219 * is also automatically freed.
221 * @param ref pointer to the buffer reference
223 void avfilter_unref_bufferp(AVFilterBufferRef **ref);
225 #if FF_API_AVFILTERPAD_PUBLIC
227 * A filter pad used for either input or output.
229 * See doc/filter_design.txt for details on how to implement the methods.
231 * @warning this struct might be removed from public API.
232 * users should call avfilter_pad_get_name() and avfilter_pad_get_type()
233 * to access the name and type fields; there should be no need to access
234 * any other fields from outside of libavfilter.
238 * Pad name. The name is unique among inputs and among outputs, but an
239 * input may have the same name as an output. This may be NULL if this
240 * pad has no need to ever be referenced by name.
247 enum AVMediaType type;
251 * Minimum required permissions on incoming buffers. Any buffer with
252 * insufficient permissions will be automatically copied by the filter
253 * system to a new buffer which provides the needed access permissions.
256 * Guaranteed permissions on outgoing buffers. Any buffer pushed on the
257 * link must have at least these permissions; this fact is checked by
258 * asserts. It can be used to optimize buffer allocation.
264 * Permissions which are not accepted on incoming buffers. Any buffer
265 * which has any of these permissions set will be automatically copied
266 * by the filter system to a new buffer which does not have those
267 * permissions. This can be used to easily disallow buffers with
271 * Permissions which are automatically removed on outgoing buffers. It
272 * can be used to optimize buffer allocation.
279 int (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
282 * Callback function to get a video buffer. If NULL, the filter system will
283 * use ff_default_get_video_buffer().
285 * Input video pads only.
287 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
290 * Callback function to get an audio buffer. If NULL, the filter system will
291 * use ff_default_get_audio_buffer().
293 * Input audio pads only.
295 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
301 int (*end_frame)(AVFilterLink *link);
306 int (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
309 * Filtering callback. This is where a filter receives a frame with
310 * audio/video data and should do its processing.
314 * @return >= 0 on success, a negative AVERROR on error. This function
315 * must ensure that frame is properly unreferenced on error if it
316 * hasn't been passed on to another filter.
318 int (*filter_frame)(AVFilterLink *link, AVFilterBufferRef *frame);
321 * Frame poll callback. This returns the number of immediately available
322 * samples. It should return a positive value if the next request_frame()
323 * is guaranteed to return one frame (with no delay).
325 * Defaults to just calling the source poll_frame() method.
329 int (*poll_frame)(AVFilterLink *link);
332 * Frame request callback. A call to this should result in at least one
333 * frame being output over the given link. This should return zero on
334 * success, and another value on error.
335 * See ff_request_frame() for the error codes with a specific
340 int (*request_frame)(AVFilterLink *link);
343 * Link configuration callback.
345 * For output pads, this should set the following link properties:
346 * video: width, height, sample_aspect_ratio, time_base
347 * audio: sample_rate.
349 * This should NOT set properties such as format, channel_layout, etc which
350 * are negotiated between filters by the filter system using the
351 * query_formats() callback before this function is called.
353 * For input pads, this should check the properties of the link, and update
354 * the filter's internal state as necessary.
356 * For both input and output pads, this should return zero on success,
357 * and another value on error.
359 int (*config_props)(AVFilterLink *link);
362 * The filter expects a fifo to be inserted on its input link,
363 * typically because it has a delay.
372 * Get the name of an AVFilterPad.
374 * @param pads an array of AVFilterPads
375 * @param pad_idx index of the pad in the array it; is the caller's
376 * responsibility to ensure the index is valid
378 * @return name of the pad_idx'th pad in pads
380 const char *avfilter_pad_get_name(AVFilterPad *pads, int pad_idx);
383 * Get the type of an AVFilterPad.
385 * @param pads an array of AVFilterPads
386 * @param pad_idx index of the pad in the array; it is the caller's
387 * responsibility to ensure the index is valid
389 * @return type of the pad_idx'th pad in pads
391 enum AVMediaType avfilter_pad_get_type(AVFilterPad *pads, int pad_idx);
394 * Filter definition. This defines the pads a filter contains, and all the
395 * callback functions used to interact with the filter.
397 typedef struct AVFilter {
398 const char *name; ///< filter name
401 * A description for the filter. You should use the
402 * NULL_IF_CONFIG_SMALL() macro to define it.
404 const char *description;
406 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
407 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
409 /*****************************************************************
410 * All fields below this line are not part of the public API. They
411 * may not be used outside of libavfilter and can be changed and
413 * New public fields should be added right above.
414 *****************************************************************
418 * Filter initialization function. Args contains the user-supplied
419 * parameters. FIXME: maybe an AVOption-based system would be better?
421 int (*init)(AVFilterContext *ctx, const char *args);
424 * Filter uninitialization function. Should deallocate any memory held
425 * by the filter, release any buffer references, etc. This does not need
426 * to deallocate the AVFilterContext->priv memory itself.
428 void (*uninit)(AVFilterContext *ctx);
431 * Queries formats/layouts supported by the filter and its pads, and sets
432 * the in_formats/in_chlayouts for links connected to its output pads,
433 * and out_formats/out_chlayouts for links connected to its input pads.
435 * @return zero on success, a negative value corresponding to an
436 * AVERROR code otherwise
438 int (*query_formats)(AVFilterContext *);
440 int priv_size; ///< size of private data to allocate for the filter
443 * Make the filter instance process a command.
445 * @param cmd the command to process, for handling simplicity all commands must be alphanumeric only
446 * @param arg the argument for the command
447 * @param res a buffer with size res_size where the filter(s) can return a response. This must not change when the command is not supported.
448 * @param flags if AVFILTER_CMD_FLAG_FAST is set and the command would be
449 * time consuming then a filter should treat it like an unsupported command
451 * @returns >=0 on success otherwise an error code.
452 * AVERROR(ENOSYS) on unsupported commands
454 int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);
457 * Filter initialization function, alternative to the init()
458 * callback. Args contains the user-supplied parameters, opaque is
459 * used for providing binary data.
461 int (*init_opaque)(AVFilterContext *ctx, const char *args, void *opaque);
463 const AVClass *priv_class; ///< private class, containing filter specific options
466 /** An instance of a filter */
467 struct AVFilterContext {
468 const AVClass *av_class; ///< needed for av_log()
470 AVFilter *filter; ///< the AVFilter of which this is an instance
472 char *name; ///< name of this filter instance
474 AVFilterPad *input_pads; ///< array of input pads
475 AVFilterLink **inputs; ///< array of pointers to input links
477 unsigned input_count; ///< @deprecated use nb_inputs
479 unsigned nb_inputs; ///< number of input pads
481 AVFilterPad *output_pads; ///< array of output pads
482 AVFilterLink **outputs; ///< array of pointers to output links
484 unsigned output_count; ///< @deprecated use nb_outputs
486 unsigned nb_outputs; ///< number of output pads
488 void *priv; ///< private data for use by the filter
490 struct AVFilterCommand *command_queue;
494 * A link between two filters. This contains pointers to the source and
495 * destination filters between which this link exists, and the indexes of
496 * the pads involved. In addition, this link also contains the parameters
497 * which have been negotiated and agreed upon between the filter, such as
498 * image dimensions, format, etc.
500 struct AVFilterLink {
501 AVFilterContext *src; ///< source filter
502 AVFilterPad *srcpad; ///< output pad on the source filter
504 AVFilterContext *dst; ///< dest filter
505 AVFilterPad *dstpad; ///< input pad on the dest filter
507 enum AVMediaType type; ///< filter media type
509 /* These parameters apply only to video */
510 int w; ///< agreed upon image width
511 int h; ///< agreed upon image height
512 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
513 /* These parameters apply only to audio */
514 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
515 int sample_rate; ///< samples per second
517 int format; ///< agreed upon media format
520 * Define the time base used by the PTS of the frames/samples
521 * which will pass through this link.
522 * During the configuration stage, each filter is supposed to
523 * change only the output timebase, while the timebase of the
524 * input link is assumed to be an unchangeable property.
526 AVRational time_base;
528 /*****************************************************************
529 * All fields below this line are not part of the public API. They
530 * may not be used outside of libavfilter and can be changed and
532 * New public fields should be added right above.
533 *****************************************************************
536 * Lists of formats and channel layouts supported by the input and output
537 * filters respectively. These lists are used for negotiating the format
538 * to actually be used, which will be loaded into the format and
539 * channel_layout members, above, when chosen.
542 AVFilterFormats *in_formats;
543 AVFilterFormats *out_formats;
546 * Lists of channel layouts and sample rates used for automatic
549 AVFilterFormats *in_samplerates;
550 AVFilterFormats *out_samplerates;
551 struct AVFilterChannelLayouts *in_channel_layouts;
552 struct AVFilterChannelLayouts *out_channel_layouts;
555 * Audio only, the destination filter sets this to a non-zero value to
556 * request that buffers with the given number of samples should be sent to
557 * it. AVFilterPad.needs_fifo must also be set on the corresponding input
559 * Last buffer before EOF will be padded with silence.
563 /** stage of the initialization of the link properties (dimensions, etc) */
565 AVLINK_UNINIT = 0, ///< not started
566 AVLINK_STARTINIT, ///< started, but incomplete
567 AVLINK_INIT ///< complete
571 * The buffer reference currently being sent across the link by the source
572 * filter. This is used internally by the filter system to allow
573 * automatic copying of buffers which do not have sufficient permissions
574 * for the destination. This should not be accessed directly by the
577 AVFilterBufferRef *src_buf;
580 * The buffer reference to the frame sent across the link by the
581 * source filter, which is read by the destination filter. It is
582 * automatically set up by ff_start_frame().
584 * Depending on the permissions, it may either be the same as
585 * src_buf or an automatic copy of it.
587 * It is automatically freed by the filter system when calling
588 * ff_end_frame(). In case you save the buffer reference
589 * internally (e.g. if you cache it for later reuse), or give it
590 * away (e.g. if you pass the reference to the next filter) it
591 * must be set to NULL before calling ff_end_frame().
593 AVFilterBufferRef *cur_buf;
596 * The buffer reference to the frame which is sent to output by
599 * If no start_frame callback is defined on a link,
600 * ff_start_frame() will automatically request a new buffer on the
601 * first output link of the destination filter. The reference to
602 * the buffer so obtained is stored in the out_buf field on the
605 * It can also be set by the filter code in case the filter needs
606 * to access the output buffer later. For example the filter code
607 * may set it in a custom start_frame, and access it in
610 * It is automatically freed by the filter system in
613 AVFilterBufferRef *out_buf;
615 struct AVFilterPool *pool;
618 * Graph the filter belongs to.
620 struct AVFilterGraph *graph;
623 * Current timestamp of the link, as defined by the most recent
624 * frame(s), in AV_TIME_BASE units.
629 * Index in the age array.
634 * Frame rate of the stream on the link, or 1/0 if unknown;
635 * if left to 0/0, will be automatically be copied from the first input
636 * of the source filter if it exists.
638 * Sources should set it to the best estimation of the real frame rate.
639 * Filters should update it if necessary depending on their function.
640 * Sinks can use it to set a default output frame rate.
641 * It is similar to the r_frame_rate field in AVStream.
643 AVRational frame_rate;
646 * Buffer partially filled with samples to achieve a fixed/minimum size.
648 AVFilterBufferRef *partial_buf;
651 * Size of the partial buffer to allocate.
652 * Must be between min_samples and max_samples.
654 int partial_buf_size;
657 * Minimum number of samples to filter at once. If filter_frame() is
658 * called with fewer samples, it will accumulate them in partial_buf.
659 * This field and the related ones must not be changed after filtering
661 * If 0, all related fields are ignored.
666 * Maximum number of samples to filter at once. If filter_frame() is
667 * called with more samples, it will split them.
672 * The buffer reference currently being received across the link by the
673 * destination filter. This is used internally by the filter system to
674 * allow automatic copying of buffers which do not have sufficient
675 * permissions for the destination. This should not be accessed directly
678 AVFilterBufferRef *cur_buf_copy;
681 * True if the link is closed.
682 * If set, all attemps of start_frame, filter_frame or request_frame
683 * will fail with AVERROR_EOF, and if necessary the reference will be
685 * If request_frame returns AVERROR_EOF, this flag is set on the
686 * corresponding link.
687 * It can be set also be set by either the source or the destination
694 * Link two filters together.
696 * @param src the source filter
697 * @param srcpad index of the output pad on the source filter
698 * @param dst the destination filter
699 * @param dstpad index of the input pad on the destination filter
700 * @return zero on success
702 int avfilter_link(AVFilterContext *src, unsigned srcpad,
703 AVFilterContext *dst, unsigned dstpad);
706 * Free the link in *link, and set its pointer to NULL.
708 void avfilter_link_free(AVFilterLink **link);
711 * Set the closed field of a link.
713 void avfilter_link_set_closed(AVFilterLink *link, int closed);
716 * Negotiate the media format, dimensions, etc of all inputs to a filter.
718 * @param filter the filter to negotiate the properties for its inputs
719 * @return zero on successful negotiation
721 int avfilter_config_links(AVFilterContext *filter);
724 * Create a buffer reference wrapped around an already allocated image
727 * @param data pointers to the planes of the image to reference
728 * @param linesize linesizes for the planes of the image to reference
729 * @param perms the required access permissions
730 * @param w the width of the image specified by the data and linesize arrays
731 * @param h the height of the image specified by the data and linesize arrays
732 * @param format the pixel format of the image specified by the data and linesize arrays
735 avfilter_get_video_buffer_ref_from_arrays(uint8_t * const data[4], const int linesize[4], int perms,
736 int w, int h, enum AVPixelFormat format);
739 * Create an audio buffer reference wrapped around an already
740 * allocated samples buffer.
742 * @param data pointers to the samples plane buffers
743 * @param linesize linesize for the samples plane buffers
744 * @param perms the required access permissions
745 * @param nb_samples number of samples per channel
746 * @param sample_fmt the format of each sample in the buffer to allocate
747 * @param channel_layout the channel layout of the buffer
749 AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
753 enum AVSampleFormat sample_fmt,
754 uint64_t channel_layout);
757 #define AVFILTER_CMD_FLAG_ONE 1 ///< Stop once a filter understood the command (for target=all for example), fast filters are favored automatically
758 #define AVFILTER_CMD_FLAG_FAST 2 ///< Only execute command when its fast (like a video out that supports contrast adjustment in hw)
761 * Make the filter instance process a command.
762 * It is recommended to use avfilter_graph_send_command().
764 int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
766 /** Initialize the filter system. Register all builtin filters. */
767 void avfilter_register_all(void);
769 /** Uninitialize the filter system. Unregister all filters. */
770 void avfilter_uninit(void);
773 * Register a filter. This is only needed if you plan to use
774 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
775 * filter can still by instantiated with avfilter_open even if it is not
778 * @param filter the filter to register
779 * @return 0 if the registration was successful, a negative value
782 int avfilter_register(AVFilter *filter);
785 * Get a filter definition matching the given name.
787 * @param name the filter name to find
788 * @return the filter definition, if any matching one is registered.
789 * NULL if none found.
791 AVFilter *avfilter_get_by_name(const char *name);
794 * If filter is NULL, returns a pointer to the first registered filter pointer,
795 * if filter is non-NULL, returns the next pointer after filter.
796 * If the returned pointer points to NULL, the last registered filter
797 * was already reached.
799 AVFilter **av_filter_next(AVFilter **filter);
802 * Create a filter instance.
804 * @param filter_ctx put here a pointer to the created filter context
805 * on success, NULL on failure
806 * @param filter the filter to create an instance of
807 * @param inst_name Name to give to the new instance. Can be NULL for none.
808 * @return >= 0 in case of success, a negative error code otherwise
810 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
813 * Initialize a filter.
815 * @param filter the filter to initialize
816 * @param args A string of parameters to use when initializing the filter.
817 * The format and meaning of this string varies by filter.
818 * @param opaque Any extra non-string data needed by the filter. The meaning
819 * of this parameter varies by filter.
820 * @return zero on success
822 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
825 * Free a filter context.
827 * @param filter the filter to free
829 void avfilter_free(AVFilterContext *filter);
832 * Insert a filter in the middle of an existing link.
834 * @param link the link into which the filter should be inserted
835 * @param filt the filter to be inserted
836 * @param filt_srcpad_idx the input pad on the filter to connect
837 * @param filt_dstpad_idx the output pad on the filter to connect
838 * @return zero on success
840 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
841 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
843 #endif /* AVFILTER_AVFILTER_H */