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/log.h"
27 #include "libavutil/samplefmt.h"
28 #include "libavutil/pixfmt.h"
29 #include "libavutil/rational.h"
30 #include "libavcodec/avcodec.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 typedef struct AVFilterContext AVFilterContext;
53 typedef struct AVFilterLink AVFilterLink;
54 typedef struct AVFilterPad AVFilterPad;
57 * A reference-counted buffer data type used by the filter system. Filters
58 * should not store pointers to this structure directly, but instead use the
59 * AVFilterBufferRef structure below.
61 typedef struct AVFilterBuffer {
62 uint8_t *data[8]; ///< buffer data for each plane/channel
63 int linesize[8]; ///< number of bytes per line
65 unsigned refcount; ///< number of references to this buffer
67 /** private data to be used by a custom free function */
70 * A pointer to the function to deallocate this buffer if the default
71 * function is not sufficient. This could, for example, add the memory
72 * back into a memory pool to be reused later without the overhead of
73 * reallocating it from scratch.
75 void (*free)(struct AVFilterBuffer *buf);
77 int format; ///< media format
78 int w, h; ///< width and height of the allocated buffer
81 #define AV_PERM_READ 0x01 ///< can read from the buffer
82 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
83 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
84 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
85 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
86 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
89 * Audio specific properties in a reference to an AVFilterBuffer. Since
90 * AVFilterBufferRef is common to different media formats, audio specific
91 * per reference properties must be separated out.
93 typedef struct AVFilterBufferRefAudioProps {
94 uint64_t channel_layout; ///< channel layout of audio buffer
95 int nb_samples; ///< number of audio samples
96 int size; ///< audio buffer size
97 uint32_t sample_rate; ///< audio buffer sample rate
98 int planar; ///< audio buffer - planar or packed
99 } AVFilterBufferRefAudioProps;
102 * Video specific properties in a reference to an AVFilterBuffer. Since
103 * AVFilterBufferRef is common to different media formats, video specific
104 * per reference properties must be separated out.
106 typedef struct AVFilterBufferRefVideoProps {
107 int w; ///< image width
108 int h; ///< image height
109 AVRational pixel_aspect; ///< pixel aspect ratio
110 int interlaced; ///< is frame interlaced
111 int top_field_first; ///< field order
112 enum AVPictureType pict_type; ///< picture type of the frame
113 int key_frame; ///< 1 -> keyframe, 0-> not
114 } AVFilterBufferRefVideoProps;
117 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
118 * a buffer to, for example, crop image without any memcpy, the buffer origin
119 * and dimensions are per-reference properties. Linesize is also useful for
120 * image flipping, frame to field filters, etc, and so is also per-reference.
122 * TODO: add anything necessary for frame reordering
124 typedef struct AVFilterBufferRef {
125 AVFilterBuffer *buf; ///< the buffer that this is a reference to
126 uint8_t *data[8]; ///< picture/audio data for each plane
127 int linesize[8]; ///< number of bytes per line
128 int format; ///< media format
131 * presentation timestamp. The time unit may change during
132 * filtering, as it is specified in the link and the filter code
133 * may need to rescale the PTS accordingly.
136 int64_t pos; ///< byte position in stream, -1 if unknown
138 int perms; ///< permissions, see the AV_PERM_* flags
140 enum AVMediaType type; ///< media type of buffer data
141 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
142 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
146 * Copy properties of src to dst, without copying the actual data
148 void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src);
151 * Add a new reference to a buffer.
153 * @param ref an existing reference to the buffer
154 * @param pmask a bitmask containing the allowable permissions in the new
156 * @return a new reference to the buffer with the same properties as the
157 * old, excluding any permissions denied by pmask
159 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
162 * Remove a reference to a buffer. If this is the last reference to the
163 * buffer, the buffer itself is also automatically freed.
165 * @param ref reference to the buffer, may be NULL
167 void avfilter_unref_buffer(AVFilterBufferRef *ref);
170 * A list of supported formats for one end of a filter link. This is used
171 * during the format negotiation process to try to pick the best format to
172 * use to minimize the number of necessary conversions. Each filter gives a
173 * list of the formats supported by each input and output pad. The list
174 * given for each pad need not be distinct - they may be references to the
175 * same list of formats, as is often the case when a filter supports multiple
176 * formats, but will always output the same format as it is given in input.
178 * In this way, a list of possible input formats and a list of possible
179 * output formats are associated with each link. When a set of formats is
180 * negotiated over a link, the input and output lists are merged to form a
181 * new list containing only the common elements of each list. In the case
182 * that there were no common elements, a format conversion is necessary.
183 * Otherwise, the lists are merged, and all other links which reference
184 * either of the format lists involved in the merge are also affected.
186 * For example, consider the filter chain:
187 * filter (a) --> (b) filter (b) --> (c) filter
189 * where the letters in parenthesis indicate a list of formats supported on
190 * the input or output of the link. Suppose the lists are as follows:
195 * First, the first link's lists are merged, yielding:
196 * filter (a) --> (a) filter (a) --> (c) filter
198 * Notice that format list (b) now refers to the same list as filter list (a).
199 * Next, the lists for the second link are merged, yielding:
200 * filter (a) --> (a) filter (a) --> (a) filter
204 * Unfortunately, when the format lists at the two ends of a link are merged,
205 * we must ensure that all links which reference either pre-merge format list
206 * get updated as well. Therefore, we have the format list structure store a
207 * pointer to each of the pointers to itself.
209 typedef struct AVFilterFormats {
210 unsigned format_count; ///< number of formats
211 int *formats; ///< list of media formats
213 unsigned refcount; ///< number of references to this list
214 struct AVFilterFormats ***refs; ///< references to this list
218 * Create a list of supported formats. This is intended for use in
219 * AVFilter->query_formats().
221 * @param fmts list of media formats, terminated by -1
222 * @return the format list, with no existing references
224 AVFilterFormats *avfilter_make_format_list(const int *fmts);
227 * Add fmt to the list of media formats contained in *avff.
228 * If *avff is NULL the function allocates the filter formats struct
229 * and puts its pointer in *avff.
231 * @return a non negative value in case of success, or a negative
232 * value corresponding to an AVERROR code in case of error
234 int avfilter_add_format(AVFilterFormats **avff, int fmt);
237 * Return a list of all formats supported by Libav for the given media type.
239 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
242 * Return a format list which contains the intersection of the formats of
243 * a and b. Also, all the references of a, all the references of b, and
244 * a and b themselves will be deallocated.
246 * If a and b do not share any common formats, neither is modified, and NULL
249 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
252 * Add *ref as a new reference to formats.
253 * That is the pointers will point like in the ascii art below:
255 * |formats |<--------.
256 * | ____ | ____|___________________
258 * | |* * | | | | | | AVFilterLink
259 * | |* *--------->|*ref|
260 * | |____| | | |____|
261 * |________| |________________________
263 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
266 * If *ref is non-NULL, remove *ref as a reference to the format list
267 * it currently points to, deallocates that list if this was the last
268 * reference, and sets *ref to NULL.
271 * ________ ________ NULL
272 * |formats |<--------. |formats | ^
273 * | ____ | ____|________________ | ____ | ____|________________
274 * | |refs| | | __|_ | |refs| | | __|_
275 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
276 * | |* *--------->|*ref| | |* | | | |*ref|
277 * | |____| | | |____| | |____| | | |____|
278 * |________| |_____________________ |________| |_____________________
280 void avfilter_formats_unref(AVFilterFormats **ref);
286 * |formats |<---------. |formats |<---------.
287 * | ____ | ___|___ | ____ | ___|___
288 * | |refs| | | | | | |refs| | | | | NULL
289 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
290 * | |* * | | |_______| | |* * | | |_______| ___|___
291 * | |____| | | |____| | | | |
292 * |________| |________| |*oldref|
295 void avfilter_formats_changeref(AVFilterFormats **oldref,
296 AVFilterFormats **newref);
299 * A filter pad used for either input or output.
303 * Pad name. The name is unique among inputs and among outputs, but an
304 * input may have the same name as an output. This may be NULL if this
305 * pad has no need to ever be referenced by name.
310 * AVFilterPad type. Only video supported now, hopefully someone will
311 * add audio in the future.
313 enum AVMediaType type;
316 * Minimum required permissions on incoming buffers. Any buffer with
317 * insufficient permissions will be automatically copied by the filter
318 * system to a new buffer which provides the needed access permissions.
325 * Permissions which are not accepted on incoming buffers. Any buffer
326 * which has any of these permissions set will be automatically copied
327 * by the filter system to a new buffer which does not have those
328 * permissions. This can be used to easily disallow buffers with
336 * Callback called before passing the first slice of a new frame. If
337 * NULL, the filter layer will default to storing a reference to the
338 * picture inside the link structure.
340 * Input video pads only.
342 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
345 * Callback function to get a video buffer. If NULL, the filter system will
346 * use avfilter_default_get_video_buffer().
348 * Input video pads only.
350 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
353 * Callback function to get an audio buffer. If NULL, the filter system will
354 * use avfilter_default_get_audio_buffer().
356 * Input audio pads only.
358 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
359 enum AVSampleFormat sample_fmt, int size,
360 uint64_t channel_layout, int planar);
363 * Callback called after the slices of a frame are completely sent. If
364 * NULL, the filter layer will default to releasing the reference stored
365 * in the link structure during start_frame().
367 * Input video pads only.
369 void (*end_frame)(AVFilterLink *link);
372 * Slice drawing callback. This is where a filter receives video data
373 * and should do its processing.
375 * Input video pads only.
377 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
380 * Samples filtering callback. This is where a filter receives audio data
381 * and should do its processing.
383 * Input audio pads only.
385 void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
388 * Frame poll callback. This returns the number of immediately available
389 * samples. It should return a positive value if the next request_frame()
390 * is guaranteed to return one frame (with no delay).
392 * Defaults to just calling the source poll_frame() method.
394 * Output video pads only.
396 int (*poll_frame)(AVFilterLink *link);
399 * Frame request callback. A call to this should result in at least one
400 * frame being output over the given link. This should return zero on
401 * success, and another value on error.
403 * Output video pads only.
405 int (*request_frame)(AVFilterLink *link);
408 * Link configuration callback.
410 * For output pads, this should set the link properties such as
411 * width/height. This should NOT set the format property - that is
412 * negotiated between filters by the filter system using the
413 * query_formats() callback before this function is called.
415 * For input pads, this should check the properties of the link, and update
416 * the filter's internal state as necessary.
418 * For both input and output filters, this should return zero on success,
419 * and another value on error.
421 int (*config_props)(AVFilterLink *link);
424 /** default handler for start_frame() for video inputs */
425 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
427 /** default handler for draw_slice() for video inputs */
428 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
430 /** default handler for end_frame() for video inputs */
431 void avfilter_default_end_frame(AVFilterLink *link);
433 /** default handler for filter_samples() for audio inputs */
434 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
436 /** default handler for config_props() for audio/video outputs */
437 int avfilter_default_config_output_link(AVFilterLink *link);
439 /** default handler for get_video_buffer() for video inputs */
440 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
441 int perms, int w, int h);
443 /** default handler for get_audio_buffer() for audio inputs */
444 AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link, int perms,
445 enum AVSampleFormat sample_fmt, int size,
446 uint64_t channel_layout, int planar);
449 * A helper for query_formats() which sets all links to the same list of
450 * formats. If there are no links hooked to this filter, the list of formats is
453 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
455 /** Default handler for query_formats() */
456 int avfilter_default_query_formats(AVFilterContext *ctx);
458 /** start_frame() handler for filters which simply pass video along */
459 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
461 /** draw_slice() handler for filters which simply pass video along */
462 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
464 /** end_frame() handler for filters which simply pass video along */
465 void avfilter_null_end_frame(AVFilterLink *link);
467 /** filter_samples() handler for filters which simply pass audio along */
468 void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
470 /** get_video_buffer() handler for filters which simply pass video along */
471 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
472 int perms, int w, int h);
474 /** get_audio_buffer() handler for filters which simply pass audio along */
475 AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link, int perms,
476 enum AVSampleFormat sample_fmt, int size,
477 uint64_t channel_layout, int planar);
480 * Filter definition. This defines the pads a filter contains, and all the
481 * callback functions used to interact with the filter.
483 typedef struct AVFilter {
484 const char *name; ///< filter name
486 int priv_size; ///< size of private data to allocate for the filter
489 * Filter initialization function. Args contains the user-supplied
490 * parameters. FIXME: maybe an AVOption-based system would be better?
491 * opaque is data provided by the code requesting creation of the filter,
492 * and is used to pass data to the filter.
494 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
497 * Filter uninitialization function. Should deallocate any memory held
498 * by the filter, release any buffer references, etc. This does not need
499 * to deallocate the AVFilterContext->priv memory itself.
501 void (*uninit)(AVFilterContext *ctx);
504 * Queries formats supported by the filter and its pads, and sets the
505 * in_formats for links connected to its output pads, and out_formats
506 * for links connected to its input pads.
508 * @return zero on success, a negative value corresponding to an
509 * AVERROR code otherwise
511 int (*query_formats)(AVFilterContext *);
513 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
514 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
517 * A description for the filter. You should use the
518 * NULL_IF_CONFIG_SMALL() macro to define it.
520 const char *description;
523 /** An instance of a filter */
524 struct AVFilterContext {
525 const AVClass *av_class; ///< needed for av_log()
527 AVFilter *filter; ///< the AVFilter of which this is an instance
529 char *name; ///< name of this filter instance
531 unsigned input_count; ///< number of input pads
532 AVFilterPad *input_pads; ///< array of input pads
533 AVFilterLink **inputs; ///< array of pointers to input links
535 unsigned output_count; ///< number of output pads
536 AVFilterPad *output_pads; ///< array of output pads
537 AVFilterLink **outputs; ///< array of pointers to output links
539 void *priv; ///< private data for use by the filter
543 * A link between two filters. This contains pointers to the source and
544 * destination filters between which this link exists, and the indexes of
545 * the pads involved. In addition, this link also contains the parameters
546 * which have been negotiated and agreed upon between the filter, such as
547 * image dimensions, format, etc.
549 struct AVFilterLink {
550 AVFilterContext *src; ///< source filter
551 AVFilterPad *srcpad; ///< output pad on the source filter
553 AVFilterContext *dst; ///< dest filter
554 AVFilterPad *dstpad; ///< input pad on the dest filter
556 /** stage of the initialization of the link properties (dimensions, etc) */
558 AVLINK_UNINIT = 0, ///< not started
559 AVLINK_STARTINIT, ///< started, but incomplete
560 AVLINK_INIT ///< complete
563 enum AVMediaType type; ///< filter media type
565 /* These parameters apply only to video */
566 int w; ///< agreed upon image width
567 int h; ///< agreed upon image height
568 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
569 /* These two parameters apply only to audio */
570 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/audioconvert.h)
571 int64_t sample_rate; ///< samples per second
573 int format; ///< agreed upon media format
576 * Lists of formats supported by the input and output filters respectively.
577 * These lists are used for negotiating the format to actually be used,
578 * which will be loaded into the format member, above, when chosen.
580 AVFilterFormats *in_formats;
581 AVFilterFormats *out_formats;
584 * The buffer reference currently being sent across the link by the source
585 * filter. This is used internally by the filter system to allow
586 * automatic copying of buffers which do not have sufficient permissions
587 * for the destination. This should not be accessed directly by the
590 AVFilterBufferRef *src_buf;
592 AVFilterBufferRef *cur_buf;
593 AVFilterBufferRef *out_buf;
596 * Define the time base used by the PTS of the frames/samples
597 * which will pass through this link.
598 * During the configuration stage, each filter is supposed to
599 * change only the output timebase, while the timebase of the
600 * input link is assumed to be an unchangeable property.
602 AVRational time_base;
606 * Link two filters together.
608 * @param src the source filter
609 * @param srcpad index of the output pad on the source filter
610 * @param dst the destination filter
611 * @param dstpad index of the input pad on the destination filter
612 * @return zero on success
614 int avfilter_link(AVFilterContext *src, unsigned srcpad,
615 AVFilterContext *dst, unsigned dstpad);
618 * Negotiate the media format, dimensions, etc of all inputs to a filter.
620 * @param filter the filter to negotiate the properties for its inputs
621 * @return zero on successful negotiation
623 int avfilter_config_links(AVFilterContext *filter);
626 * Request a picture buffer with a specific set of permissions.
628 * @param link the output link to the filter from which the buffer will
630 * @param perms the required access permissions
631 * @param w the minimum width of the buffer to allocate
632 * @param h the minimum height of the buffer to allocate
633 * @return A reference to the buffer. This must be unreferenced with
634 * avfilter_unref_buffer when you are finished with it.
636 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
640 * Create a buffer reference wrapped around an already allocated image
643 * @param data pointers to the planes of the image to reference
644 * @param linesize linesizes for the planes of the image to reference
645 * @param perms the required access permissions
646 * @param w the width of the image specified by the data and linesize arrays
647 * @param h the height of the image specified by the data and linesize arrays
648 * @param format the pixel format of the image specified by the data and linesize arrays
651 avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int perms,
652 int w, int h, enum PixelFormat format);
655 * Request an audio samples buffer with a specific set of permissions.
657 * @param link the output link to the filter from which the buffer will
659 * @param perms the required access permissions
660 * @param sample_fmt the format of each sample in the buffer to allocate
661 * @param size the buffer size in bytes
662 * @param channel_layout the number and type of channels per sample in the buffer to allocate
663 * @param planar audio data layout - planar or packed
664 * @return A reference to the samples. This must be unreferenced with
665 * avfilter_unref_buffer when you are finished with it.
667 AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,
668 enum AVSampleFormat sample_fmt, int size,
669 uint64_t channel_layout, int planar);
672 * Request an input frame from the filter at the other end of the link.
674 * @param link the input link
675 * @return zero on success
677 int avfilter_request_frame(AVFilterLink *link);
680 * Poll a frame from the filter chain.
682 * @param link the input link
683 * @return the number of immediately available frames, a negative
684 * number in case of error
686 int avfilter_poll_frame(AVFilterLink *link);
689 * Notify the next filter of the start of a frame.
691 * @param link the output link the frame will be sent over
692 * @param picref A reference to the frame about to be sent. The data for this
693 * frame need only be valid once draw_slice() is called for that
694 * portion. The receiving filter will free this reference when
695 * it no longer needs it.
697 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
700 * Notifie the next filter that the current frame has finished.
702 * @param link the output link the frame was sent over
704 void avfilter_end_frame(AVFilterLink *link);
707 * Send a slice to the next filter.
709 * Slices have to be provided in sequential order, either in
710 * top-bottom or bottom-top order. If slices are provided in
711 * non-sequential order the behavior of the function is undefined.
713 * @param link the output link over which the frame is being sent
714 * @param y offset in pixels from the top of the image for this slice
715 * @param h height of this slice in pixels
716 * @param slice_dir the assumed direction for sending slices,
717 * from the top slice to the bottom slice if the value is 1,
718 * from the bottom slice to the top slice if the value is -1,
719 * for other values the behavior of the function is undefined.
721 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
724 * Send a buffer of audio samples to the next filter.
726 * @param link the output link over which the audio samples are being sent
727 * @param samplesref a reference to the buffer of audio samples being sent. The
728 * receiving filter will free this reference when it no longer
729 * needs it or pass it on to the next filter.
731 void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
733 /** Initialize the filter system. Register all builtin filters. */
734 void avfilter_register_all(void);
736 /** Uninitialize the filter system. Unregister all filters. */
737 void avfilter_uninit(void);
740 * Register a filter. This is only needed if you plan to use
741 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
742 * filter can still by instantiated with avfilter_open even if it is not
745 * @param filter the filter to register
746 * @return 0 if the registration was succesfull, a negative value
749 int avfilter_register(AVFilter *filter);
752 * Get a filter definition matching the given name.
754 * @param name the filter name to find
755 * @return the filter definition, if any matching one is registered.
756 * NULL if none found.
758 AVFilter *avfilter_get_by_name(const char *name);
761 * If filter is NULL, returns a pointer to the first registered filter pointer,
762 * if filter is non-NULL, returns the next pointer after filter.
763 * If the returned pointer points to NULL, the last registered filter
764 * was already reached.
766 AVFilter **av_filter_next(AVFilter **filter);
769 * Create a filter instance.
771 * @param filter_ctx put here a pointer to the created filter context
772 * on success, NULL on failure
773 * @param filter the filter to create an instance of
774 * @param inst_name Name to give to the new instance. Can be NULL for none.
775 * @return >= 0 in case of success, a negative error code otherwise
777 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
780 * Initialize a filter.
782 * @param filter the filter to initialize
783 * @param args A string of parameters to use when initializing the filter.
784 * The format and meaning of this string varies by filter.
785 * @param opaque Any extra non-string data needed by the filter. The meaning
786 * of this parameter varies by filter.
787 * @return zero on success
789 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
792 * Free a filter context.
794 * @param filter the filter to free
796 void avfilter_free(AVFilterContext *filter);
799 * Insert a filter in the middle of an existing link.
801 * @param link the link into which the filter should be inserted
802 * @param filt the filter to be inserted
803 * @param filt_srcpad_idx the input pad on the filter to connect
804 * @param filt_dstpad_idx the output pad on the filter to connect
805 * @return zero on success
807 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
808 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
813 * @param idx Insertion point. Pad is inserted at the end if this point
814 * is beyond the end of the list of pads.
815 * @param count Pointer to the number of pads in the list
816 * @param padidx_off Offset within an AVFilterLink structure to the element
817 * to increment when inserting a new pad causes link
818 * numbering to change
819 * @param pads Pointer to the pointer to the beginning of the list of pads
820 * @param links Pointer to the pointer to the beginning of the list of links
821 * @param newpad The new pad to add. A copy is made when adding.
823 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
824 AVFilterPad **pads, AVFilterLink ***links,
825 AVFilterPad *newpad);
827 /** Insert a new input pad for the filter. */
828 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
831 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
832 &f->input_pads, &f->inputs, p);
835 /** Insert a new output pad for the filter. */
836 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
839 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
840 &f->output_pads, &f->outputs, p);
844 * Copy the frame properties of src to dst, without copying the actual
847 * @return 0 on success, a negative number on error.
849 int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
852 * Copy the frame properties and data pointers of src to dst, without copying
855 * @return 0 on success, a negative number on error.
857 int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src);
859 #endif /* AVFILTER_AVFILTER_H */