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
25 #include "libavutil/avutil.h"
26 #include "libavutil/samplefmt.h"
28 #define LIBAVFILTER_VERSION_MAJOR 2
29 #define LIBAVFILTER_VERSION_MINOR 15
30 #define LIBAVFILTER_VERSION_MICRO 0
32 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
33 LIBAVFILTER_VERSION_MINOR, \
34 LIBAVFILTER_VERSION_MICRO)
35 #define LIBAVFILTER_VERSION AV_VERSION(LIBAVFILTER_VERSION_MAJOR, \
36 LIBAVFILTER_VERSION_MINOR, \
37 LIBAVFILTER_VERSION_MICRO)
38 #define LIBAVFILTER_BUILD LIBAVFILTER_VERSION_INT
43 * Return the LIBAVFILTER_VERSION_INT constant.
45 unsigned avfilter_version(void);
48 * Return the libavfilter build-time configuration.
50 const char *avfilter_configuration(void);
53 * Return the libavfilter license.
55 const char *avfilter_license(void);
58 typedef struct AVFilterContext AVFilterContext;
59 typedef struct AVFilterLink AVFilterLink;
60 typedef struct AVFilterPad AVFilterPad;
63 * A reference-counted buffer data type used by the filter system. Filters
64 * should not store pointers to this structure directly, but instead use the
65 * AVFilterBufferRef structure below.
67 typedef struct AVFilterBuffer {
68 uint8_t *data[8]; ///< buffer data for each plane/channel
69 int linesize[8]; ///< number of bytes per line
71 unsigned refcount; ///< number of references to this buffer
73 /** private data to be used by a custom free function */
76 * A pointer to the function to deallocate this buffer if the default
77 * function is not sufficient. This could, for example, add the memory
78 * back into a memory pool to be reused later without the overhead of
79 * reallocating it from scratch.
81 void (*free)(struct AVFilterBuffer *buf);
83 int format; ///< media format
84 int w, h; ///< width and height of the allocated buffer
87 #define AV_PERM_READ 0x01 ///< can read from the buffer
88 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
89 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
90 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
91 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
92 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
95 * Audio specific properties in a reference to an AVFilterBuffer. Since
96 * AVFilterBufferRef is common to different media formats, audio specific
97 * per reference properties must be separated out.
99 typedef struct AVFilterBufferRefAudioProps {
100 int64_t channel_layout; ///< channel layout of audio buffer
101 int nb_samples; ///< number of audio samples per channel
102 uint32_t sample_rate; ///< audio buffer sample rate
103 int planar; ///< audio buffer - planar or packed
104 } AVFilterBufferRefAudioProps;
107 * Video specific properties in a reference to an AVFilterBuffer. Since
108 * AVFilterBufferRef is common to different media formats, video specific
109 * per reference properties must be separated out.
111 typedef struct AVFilterBufferRefVideoProps {
112 int w; ///< image width
113 int h; ///< image height
114 AVRational sample_aspect_ratio; ///< sample aspect ratio
115 int interlaced; ///< is frame interlaced
116 int top_field_first; ///< field order
117 enum AVPictureType pict_type; ///< picture type of the frame
118 int key_frame; ///< 1 -> keyframe, 0-> not
119 } AVFilterBufferRefVideoProps;
122 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
123 * a buffer to, for example, crop image without any memcpy, the buffer origin
124 * and dimensions are per-reference properties. Linesize is also useful for
125 * image flipping, frame to field filters, etc, and so is also per-reference.
127 * TODO: add anything necessary for frame reordering
129 typedef struct AVFilterBufferRef {
130 AVFilterBuffer *buf; ///< the buffer that this is a reference to
131 uint8_t *data[8]; ///< picture/audio data for each plane
132 int linesize[8]; ///< number of bytes per line
133 int format; ///< media format
136 * presentation timestamp. The time unit may change during
137 * filtering, as it is specified in the link and the filter code
138 * may need to rescale the PTS accordingly.
141 int64_t pos; ///< byte position in stream, -1 if unknown
143 int perms; ///< permissions, see the AV_PERM_* flags
145 enum AVMediaType type; ///< media type of buffer data
146 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
147 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
151 * Copy properties of src to dst, without copying the actual data
153 static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
155 // copy common properties
160 case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
161 case AVMEDIA_TYPE_AUDIO: *dst->audio = *src->audio; break;
166 * Add a new reference to a buffer.
168 * @param ref an existing reference to the buffer
169 * @param pmask a bitmask containing the allowable permissions in the new
171 * @return a new reference to the buffer with the same properties as the
172 * old, excluding any permissions denied by pmask
174 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
177 * Remove a reference to a buffer. If this is the last reference to the
178 * buffer, the buffer itself is also automatically freed.
180 * @param ref reference to the buffer, may be NULL
182 void avfilter_unref_buffer(AVFilterBufferRef *ref);
185 * A list of supported formats for one end of a filter link. This is used
186 * during the format negotiation process to try to pick the best format to
187 * use to minimize the number of necessary conversions. Each filter gives a
188 * list of the formats supported by each input and output pad. The list
189 * given for each pad need not be distinct - they may be references to the
190 * same list of formats, as is often the case when a filter supports multiple
191 * formats, but will always output the same format as it is given in input.
193 * In this way, a list of possible input formats and a list of possible
194 * output formats are associated with each link. When a set of formats is
195 * negotiated over a link, the input and output lists are merged to form a
196 * new list containing only the common elements of each list. In the case
197 * that there were no common elements, a format conversion is necessary.
198 * Otherwise, the lists are merged, and all other links which reference
199 * either of the format lists involved in the merge are also affected.
201 * For example, consider the filter chain:
202 * filter (a) --> (b) filter (b) --> (c) filter
204 * where the letters in parenthesis indicate a list of formats supported on
205 * the input or output of the link. Suppose the lists are as follows:
210 * First, the first link's lists are merged, yielding:
211 * filter (a) --> (a) filter (a) --> (c) filter
213 * Notice that format list (b) now refers to the same list as filter list (a).
214 * Next, the lists for the second link are merged, yielding:
215 * filter (a) --> (a) filter (a) --> (a) filter
219 * Unfortunately, when the format lists at the two ends of a link are merged,
220 * we must ensure that all links which reference either pre-merge format list
221 * get updated as well. Therefore, we have the format list structure store a
222 * pointer to each of the pointers to itself.
224 typedef struct AVFilterFormats {
225 unsigned format_count; ///< number of formats
226 int *formats; ///< list of media formats
228 unsigned refcount; ///< number of references to this list
229 struct AVFilterFormats ***refs; ///< references to this list
233 * Create a list of supported formats. This is intended for use in
234 * AVFilter->query_formats().
236 * @param fmts list of media formats, terminated by -1. If NULL an
237 * empty list is created.
238 * @return the format list, with no existing references
240 AVFilterFormats *avfilter_make_format_list(const int *fmts);
243 * Add fmt to the list of media formats contained in *avff.
244 * If *avff is NULL the function allocates the filter formats struct
245 * and puts its pointer in *avff.
247 * @return a non negative value in case of success, or a negative
248 * value corresponding to an AVERROR code in case of error
250 int avfilter_add_format(AVFilterFormats **avff, int fmt);
253 * Return a list of all formats supported by FFmpeg for the given media type.
255 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
258 * Return a format list which contains the intersection of the formats of
259 * a and b. Also, all the references of a, all the references of b, and
260 * a and b themselves will be deallocated.
262 * If a and b do not share any common formats, neither is modified, and NULL
265 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
268 * Add *ref as a new reference to formats.
269 * That is the pointers will point like in the ascii art below:
271 * |formats |<--------.
272 * | ____ | ____|___________________
274 * | |* * | | | | | | AVFilterLink
275 * | |* *--------->|*ref|
276 * | |____| | | |____|
277 * |________| |________________________
279 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
282 * If *ref is non-NULL, remove *ref as a reference to the format list
283 * it currently points to, deallocates that list if this was the last
284 * reference, and sets *ref to NULL.
287 * ________ ________ NULL
288 * |formats |<--------. |formats | ^
289 * | ____ | ____|________________ | ____ | ____|________________
290 * | |refs| | | __|_ | |refs| | | __|_
291 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
292 * | |* *--------->|*ref| | |* | | | |*ref|
293 * | |____| | | |____| | |____| | | |____|
294 * |________| |_____________________ |________| |_____________________
296 void avfilter_formats_unref(AVFilterFormats **ref);
302 * |formats |<---------. |formats |<---------.
303 * | ____ | ___|___ | ____ | ___|___
304 * | |refs| | | | | | |refs| | | | | NULL
305 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
306 * | |* * | | |_______| | |* * | | |_______| ___|___
307 * | |____| | | |____| | | | |
308 * |________| |________| |*oldref|
311 void avfilter_formats_changeref(AVFilterFormats **oldref,
312 AVFilterFormats **newref);
315 * A filter pad used for either input or output.
319 * Pad name. The name is unique among inputs and among outputs, but an
320 * input may have the same name as an output. This may be NULL if this
321 * pad has no need to ever be referenced by name.
326 * AVFilterPad type. Only video supported now, hopefully someone will
327 * add audio in the future.
329 enum AVMediaType type;
332 * Minimum required permissions on incoming buffers. Any buffer with
333 * insufficient permissions will be automatically copied by the filter
334 * system to a new buffer which provides the needed access permissions.
341 * Permissions which are not accepted on incoming buffers. Any buffer
342 * which has any of these permissions set will be automatically copied
343 * by the filter system to a new buffer which does not have those
344 * permissions. This can be used to easily disallow buffers with
352 * Callback called before passing the first slice of a new frame. If
353 * NULL, the filter layer will default to storing a reference to the
354 * picture inside the link structure.
356 * Input video pads only.
358 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
361 * Callback function to get a video buffer. If NULL, the filter system will
362 * use avfilter_default_get_video_buffer().
364 * Input video pads only.
366 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
369 * Callback function to get an audio buffer. If NULL, the filter system will
370 * use avfilter_default_get_audio_buffer().
372 * Input audio pads only.
374 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
375 enum AVSampleFormat sample_fmt, int nb_samples,
376 int64_t channel_layout, int planar);
379 * Callback called after the slices of a frame are completely sent. If
380 * NULL, the filter layer will default to releasing the reference stored
381 * in the link structure during start_frame().
383 * Input video pads only.
385 void (*end_frame)(AVFilterLink *link);
388 * Slice drawing callback. This is where a filter receives video data
389 * and should do its processing.
391 * Input video pads only.
393 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
396 * Samples filtering callback. This is where a filter receives audio data
397 * and should do its processing.
399 * Input audio pads only.
401 void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
404 * Frame poll callback. This returns the number of immediately available
405 * samples. It should return a positive value if the next request_frame()
406 * is guaranteed to return one frame (with no delay).
408 * Defaults to just calling the source poll_frame() method.
410 * Output video pads only.
412 int (*poll_frame)(AVFilterLink *link);
415 * Frame request callback. A call to this should result in at least one
416 * frame being output over the given link. This should return zero on
417 * success, and another value on error.
419 * Output video pads only.
421 int (*request_frame)(AVFilterLink *link);
424 * Link configuration callback.
426 * For output pads, this should set the link properties such as
427 * width/height. This should NOT set the format property - that is
428 * negotiated between filters by the filter system using the
429 * query_formats() callback before this function is called.
431 * For input pads, this should check the properties of the link, and update
432 * the filter's internal state as necessary.
434 * For both input and output filters, this should return zero on success,
435 * and another value on error.
437 int (*config_props)(AVFilterLink *link);
440 /** default handler for start_frame() for video inputs */
441 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
443 /** default handler for draw_slice() for video inputs */
444 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
446 /** default handler for end_frame() for video inputs */
447 void avfilter_default_end_frame(AVFilterLink *link);
449 /** default handler for filter_samples() for audio inputs */
450 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
452 /** default handler for config_props() for audio/video outputs */
453 int avfilter_default_config_output_link(AVFilterLink *link);
455 /** default handler for config_props() for audio/video inputs */
456 int avfilter_default_config_input_link (AVFilterLink *link);
458 /** default handler for get_video_buffer() for video inputs */
459 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
460 int perms, int w, int h);
462 /** default handler for get_audio_buffer() for audio inputs */
463 AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link, int perms,
464 enum AVSampleFormat sample_fmt, int nb_samples,
465 int64_t channel_layout, int planar);
468 * A helper for query_formats() which sets all links to the same list of
469 * formats. If there are no links hooked to this filter, the list of formats is
472 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
474 /** Default handler for query_formats() */
475 int avfilter_default_query_formats(AVFilterContext *ctx);
477 /** start_frame() handler for filters which simply pass video along */
478 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
480 /** draw_slice() handler for filters which simply pass video along */
481 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
483 /** end_frame() handler for filters which simply pass video along */
484 void avfilter_null_end_frame(AVFilterLink *link);
486 /** filter_samples() handler for filters which simply pass audio along */
487 void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
489 /** get_video_buffer() handler for filters which simply pass video along */
490 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
491 int perms, int w, int h);
493 /** get_audio_buffer() handler for filters which simply pass audio along */
494 AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link, int perms,
495 enum AVSampleFormat sample_fmt, int size,
496 int64_t channel_layout, int planar);
499 * Filter definition. This defines the pads a filter contains, and all the
500 * callback functions used to interact with the filter.
502 typedef struct AVFilter {
503 const char *name; ///< filter name
505 int priv_size; ///< size of private data to allocate for the filter
508 * Filter initialization function. Args contains the user-supplied
509 * parameters. FIXME: maybe an AVOption-based system would be better?
510 * opaque is data provided by the code requesting creation of the filter,
511 * and is used to pass data to the filter.
513 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
516 * Filter uninitialization function. Should deallocate any memory held
517 * by the filter, release any buffer references, etc. This does not need
518 * to deallocate the AVFilterContext->priv memory itself.
520 void (*uninit)(AVFilterContext *ctx);
523 * Queries formats supported by the filter and its pads, and sets the
524 * in_formats for links connected to its output pads, and out_formats
525 * for links connected to its input pads.
527 * @return zero on success, a negative value corresponding to an
528 * AVERROR code otherwise
530 int (*query_formats)(AVFilterContext *);
532 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
533 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
536 * A description for the filter. You should use the
537 * NULL_IF_CONFIG_SMALL() macro to define it.
539 const char *description;
542 /** An instance of a filter */
543 struct AVFilterContext {
544 const AVClass *av_class; ///< needed for av_log()
546 AVFilter *filter; ///< the AVFilter of which this is an instance
548 char *name; ///< name of this filter instance
550 unsigned input_count; ///< number of input pads
551 AVFilterPad *input_pads; ///< array of input pads
552 AVFilterLink **inputs; ///< array of pointers to input links
554 unsigned output_count; ///< number of output pads
555 AVFilterPad *output_pads; ///< array of output pads
556 AVFilterLink **outputs; ///< array of pointers to output links
558 void *priv; ///< private data for use by the filter
562 * A link between two filters. This contains pointers to the source and
563 * destination filters between which this link exists, and the indexes of
564 * the pads involved. In addition, this link also contains the parameters
565 * which have been negotiated and agreed upon between the filter, such as
566 * image dimensions, format, etc.
568 struct AVFilterLink {
569 AVFilterContext *src; ///< source filter
570 AVFilterPad *srcpad; ///< output pad on the source filter
572 AVFilterContext *dst; ///< dest filter
573 AVFilterPad *dstpad; ///< input pad on the dest filter
575 /** stage of the initialization of the link properties (dimensions, etc) */
577 AVLINK_UNINIT = 0, ///< not started
578 AVLINK_STARTINIT, ///< started, but incomplete
579 AVLINK_INIT ///< complete
582 enum AVMediaType type; ///< filter media type
584 /* These parameters apply only to video */
585 int w; ///< agreed upon image width
586 int h; ///< agreed upon image height
587 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
588 /* These two parameters apply only to audio */
589 int64_t channel_layout; ///< channel layout of current buffer (see libavutil/audioconvert.h)
590 int64_t sample_rate; ///< samples per second
592 int format; ///< agreed upon media format
595 * Lists of formats supported by the input and output filters respectively.
596 * These lists are used for negotiating the format to actually be used,
597 * which will be loaded into the format member, above, when chosen.
599 AVFilterFormats *in_formats;
600 AVFilterFormats *out_formats;
603 * The buffer reference currently being sent across the link by the source
604 * filter. This is used internally by the filter system to allow
605 * automatic copying of buffers which do not have sufficient permissions
606 * for the destination. This should not be accessed directly by the
609 AVFilterBufferRef *src_buf;
611 AVFilterBufferRef *cur_buf;
612 AVFilterBufferRef *out_buf;
615 * Define the time base used by the PTS of the frames/samples
616 * which will pass through this link.
617 * During the configuration stage, each filter is supposed to
618 * change only the output timebase, while the timebase of the
619 * input link is assumed to be an unchangeable property.
621 AVRational time_base;
623 struct AVFilterPool *pool;
627 * Link two filters together.
629 * @param src the source filter
630 * @param srcpad index of the output pad on the source filter
631 * @param dst the destination filter
632 * @param dstpad index of the input pad on the destination filter
633 * @return zero on success
635 int avfilter_link(AVFilterContext *src, unsigned srcpad,
636 AVFilterContext *dst, unsigned dstpad);
639 * Free the link in *link, and set its pointer to NULL.
641 void avfilter_link_free(AVFilterLink **link);
644 * Negotiate the media format, dimensions, etc of all inputs to a filter.
646 * @param filter the filter to negotiate the properties for its inputs
647 * @return zero on successful negotiation
649 int avfilter_config_links(AVFilterContext *filter);
652 * Request a picture buffer with a specific set of permissions.
654 * @param link the output link to the filter from which the buffer will
656 * @param perms the required access permissions
657 * @param w the minimum width of the buffer to allocate
658 * @param h the minimum height of the buffer to allocate
659 * @return A reference to the buffer. This must be unreferenced with
660 * avfilter_unref_buffer when you are finished with it.
662 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
666 * Create a buffer reference wrapped around an already allocated image
669 * @param data pointers to the planes of the image to reference
670 * @param linesize linesizes for the planes of the image to reference
671 * @param perms the required access permissions
672 * @param w the width of the image specified by the data and linesize arrays
673 * @param h the height of the image specified by the data and linesize arrays
674 * @param format the pixel format of the image specified by the data and linesize arrays
677 avfilter_get_video_buffer_ref_from_arrays(uint8_t * const data[4], const int linesize[4], int perms,
678 int w, int h, enum PixelFormat format);
681 * Request an audio samples buffer with a specific set of permissions.
683 * @param link the output link to the filter from which the buffer will
685 * @param perms the required access permissions
686 * @param sample_fmt the format of each sample in the buffer to allocate
687 * @param nb_samples the number of samples per channel
688 * @param channel_layout the number and type of channels per sample in the buffer to allocate
689 * @param planar audio data layout - planar or packed
690 * @return A reference to the samples. This must be unreferenced with
691 * avfilter_unref_buffer when you are finished with it.
693 AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,
694 enum AVSampleFormat sample_fmt, int nb_samples,
695 int64_t channel_layout, int planar);
698 * Create an audio buffer reference wrapped around an already
699 * allocated samples buffer.
701 * @param data pointers to the samples plane buffers
702 * @param linesize linesize for the samples plane buffers
703 * @param perms the required access permissions
704 * @param nb_samples number of samples per channel
705 * @param sample_fmt the format of each sample in the buffer to allocate
706 * @param channel_layout the channel layout of the buffer
707 * @param planar audio data layout - planar or packed
710 avfilter_get_audio_buffer_ref_from_arrays(uint8_t *data[8], int linesize[8], int perms,
711 int nb_samples, enum AVSampleFormat sample_fmt,
712 int64_t channel_layout, int planar);
715 * Request an input frame from the filter at the other end of the link.
717 * @param link the input link
718 * @return zero on success
720 int avfilter_request_frame(AVFilterLink *link);
723 * Poll a frame from the filter chain.
725 * @param link the input link
726 * @return the number of immediately available frames, a negative
727 * number in case of error
729 int avfilter_poll_frame(AVFilterLink *link);
732 * Notifie the next filter of the start of a frame.
734 * @param link the output link the frame will be sent over
735 * @param picref A reference to the frame about to be sent. The data for this
736 * frame need only be valid once draw_slice() is called for that
737 * portion. The receiving filter will free this reference when
738 * it no longer needs it.
740 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
743 * Notifie the next filter that the current frame has finished.
745 * @param link the output link the frame was sent over
747 void avfilter_end_frame(AVFilterLink *link);
750 * Send a slice to the next filter.
752 * Slices have to be provided in sequential order, either in
753 * top-bottom or bottom-top order. If slices are provided in
754 * non-sequential order the behavior of the function is undefined.
756 * @param link the output link over which the frame is being sent
757 * @param y offset in pixels from the top of the image for this slice
758 * @param h height of this slice in pixels
759 * @param slice_dir the assumed direction for sending slices,
760 * from the top slice to the bottom slice if the value is 1,
761 * from the bottom slice to the top slice if the value is -1,
762 * for other values the behavior of the function is undefined.
764 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
767 * Send a buffer of audio samples to the next filter.
769 * @param link the output link over which the audio samples are being sent
770 * @param samplesref a reference to the buffer of audio samples being sent. The
771 * receiving filter will free this reference when it no longer
772 * needs it or pass it on to the next filter.
774 void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
776 /** Initialize the filter system. Register all builtin filters. */
777 void avfilter_register_all(void);
779 /** Uninitialize the filter system. Unregister all filters. */
780 void avfilter_uninit(void);
783 * Register a filter. This is only needed if you plan to use
784 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
785 * filter can still by instantiated with avfilter_open even if it is not
788 * @param filter the filter to register
789 * @return 0 if the registration was succesfull, a negative value
792 int avfilter_register(AVFilter *filter);
795 * Get a filter definition matching the given name.
797 * @param name the filter name to find
798 * @return the filter definition, if any matching one is registered.
799 * NULL if none found.
801 AVFilter *avfilter_get_by_name(const char *name);
804 * If filter is NULL, returns a pointer to the first registered filter pointer,
805 * if filter is non-NULL, returns the next pointer after filter.
806 * If the returned pointer points to NULL, the last registered filter
807 * was already reached.
809 AVFilter **av_filter_next(AVFilter **filter);
812 * Create a filter instance.
814 * @param filter_ctx put here a pointer to the created filter context
815 * on success, NULL on failure
816 * @param filter the filter to create an instance of
817 * @param inst_name Name to give to the new instance. Can be NULL for none.
818 * @return >= 0 in case of success, a negative error code otherwise
820 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
823 * Initialize a filter.
825 * @param filter the filter to initialize
826 * @param args A string of parameters to use when initializing the filter.
827 * The format and meaning of this string varies by filter.
828 * @param opaque Any extra non-string data needed by the filter. The meaning
829 * of this parameter varies by filter.
830 * @return zero on success
832 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
835 * Free a filter context.
837 * @param filter the filter to free
839 void avfilter_free(AVFilterContext *filter);
842 * Insert a filter in the middle of an existing link.
844 * @param link the link into which the filter should be inserted
845 * @param filt the filter to be inserted
846 * @param filt_srcpad_idx the input pad on the filter to connect
847 * @param filt_dstpad_idx the output pad on the filter to connect
848 * @return zero on success
850 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
851 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
856 * @param idx Insertion point. Pad is inserted at the end if this point
857 * is beyond the end of the list of pads.
858 * @param count Pointer to the number of pads in the list
859 * @param padidx_off Offset within an AVFilterLink structure to the element
860 * to increment when inserting a new pad causes link
861 * numbering to change
862 * @param pads Pointer to the pointer to the beginning of the list of pads
863 * @param links Pointer to the pointer to the beginning of the list of links
864 * @param newpad The new pad to add. A copy is made when adding.
866 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
867 AVFilterPad **pads, AVFilterLink ***links,
868 AVFilterPad *newpad);
870 /** Insert a new input pad for the filter. */
871 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
874 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
875 &f->input_pads, &f->inputs, p);
878 /** Insert a new output pad for the filter. */
879 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
882 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
883 &f->output_pads, &f->outputs, p);
886 #endif /* AVFILTER_AVFILTER_H */