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/log.h"
27 #include "libavutil/samplefmt.h"
28 #include "libavutil/pixfmt.h"
29 #include "libavutil/rational.h"
31 #define LIBAVFILTER_VERSION_MAJOR 2
32 #define LIBAVFILTER_VERSION_MINOR 24
33 #define LIBAVFILTER_VERSION_MICRO 4
35 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
36 LIBAVFILTER_VERSION_MINOR, \
37 LIBAVFILTER_VERSION_MICRO)
38 #define LIBAVFILTER_VERSION AV_VERSION(LIBAVFILTER_VERSION_MAJOR, \
39 LIBAVFILTER_VERSION_MINOR, \
40 LIBAVFILTER_VERSION_MICRO)
41 #define LIBAVFILTER_BUILD LIBAVFILTER_VERSION_INT
46 * Return the LIBAVFILTER_VERSION_INT constant.
48 unsigned avfilter_version(void);
51 * Return the libavfilter build-time configuration.
53 const char *avfilter_configuration(void);
56 * Return the libavfilter license.
58 const char *avfilter_license(void);
61 typedef struct AVFilterContext AVFilterContext;
62 typedef struct AVFilterLink AVFilterLink;
63 typedef struct AVFilterPad AVFilterPad;
66 * A reference-counted buffer data type used by the filter system. Filters
67 * should not store pointers to this structure directly, but instead use the
68 * AVFilterBufferRef structure below.
70 typedef struct AVFilterBuffer {
71 uint8_t *data[8]; ///< buffer data for each plane/channel
72 int linesize[8]; ///< number of bytes per line
74 unsigned refcount; ///< number of references to this buffer
76 /** private data to be used by a custom free function */
79 * A pointer to the function to deallocate this buffer if the default
80 * function is not sufficient. This could, for example, add the memory
81 * back into a memory pool to be reused later without the overhead of
82 * reallocating it from scratch.
84 void (*free)(struct AVFilterBuffer *buf);
86 int format; ///< media format
87 int w, h; ///< width and height of the allocated buffer
90 #define AV_PERM_READ 0x01 ///< can read from the buffer
91 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
92 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
93 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
94 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
95 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
98 * Audio specific properties in a reference to an AVFilterBuffer. Since
99 * AVFilterBufferRef is common to different media formats, audio specific
100 * per reference properties must be separated out.
102 typedef struct AVFilterBufferRefAudioProps {
103 int64_t channel_layout; ///< channel layout of audio buffer
104 int nb_samples; ///< number of audio samples per channel
105 uint32_t sample_rate; ///< audio buffer sample rate
106 int planar; ///< audio buffer - planar or packed
107 } AVFilterBufferRefAudioProps;
110 * Video specific properties in a reference to an AVFilterBuffer. Since
111 * AVFilterBufferRef is common to different media formats, video specific
112 * per reference properties must be separated out.
114 typedef struct AVFilterBufferRefVideoProps {
115 int w; ///< image width
116 int h; ///< image height
117 AVRational sample_aspect_ratio; ///< sample aspect ratio
118 int interlaced; ///< is frame interlaced
119 int top_field_first; ///< field order
120 enum AVPictureType pict_type; ///< picture type of the frame
121 int key_frame; ///< 1 -> keyframe, 0-> not
122 } AVFilterBufferRefVideoProps;
125 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
126 * a buffer to, for example, crop image without any memcpy, the buffer origin
127 * and dimensions are per-reference properties. Linesize is also useful for
128 * image flipping, frame to field filters, etc, and so is also per-reference.
130 * TODO: add anything necessary for frame reordering
132 typedef struct AVFilterBufferRef {
133 AVFilterBuffer *buf; ///< the buffer that this is a reference to
134 uint8_t *data[8]; ///< picture/audio data for each plane
135 int linesize[8]; ///< number of bytes per line
136 int format; ///< media format
139 * presentation timestamp. The time unit may change during
140 * filtering, as it is specified in the link and the filter code
141 * may need to rescale the PTS accordingly.
144 int64_t pos; ///< byte position in stream, -1 if unknown
146 int perms; ///< permissions, see the AV_PERM_* flags
148 enum AVMediaType type; ///< media type of buffer data
149 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
150 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
154 * Copy properties of src to dst, without copying the actual data
156 static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
158 // copy common properties
163 case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
164 case AVMEDIA_TYPE_AUDIO: *dst->audio = *src->audio; break;
170 * Add a new reference to a buffer.
172 * @param ref an existing reference to the buffer
173 * @param pmask a bitmask containing the allowable permissions in the new
175 * @return a new reference to the buffer with the same properties as the
176 * old, excluding any permissions denied by pmask
178 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
181 * Remove a reference to a buffer. If this is the last reference to the
182 * buffer, the buffer itself is also automatically freed.
184 * @param ref reference to the buffer, may be NULL
186 void avfilter_unref_buffer(AVFilterBufferRef *ref);
189 * A list of supported formats for one end of a filter link. This is used
190 * during the format negotiation process to try to pick the best format to
191 * use to minimize the number of necessary conversions. Each filter gives a
192 * list of the formats supported by each input and output pad. The list
193 * given for each pad need not be distinct - they may be references to the
194 * same list of formats, as is often the case when a filter supports multiple
195 * formats, but will always output the same format as it is given in input.
197 * In this way, a list of possible input formats and a list of possible
198 * output formats are associated with each link. When a set of formats is
199 * negotiated over a link, the input and output lists are merged to form a
200 * new list containing only the common elements of each list. In the case
201 * that there were no common elements, a format conversion is necessary.
202 * Otherwise, the lists are merged, and all other links which reference
203 * either of the format lists involved in the merge are also affected.
205 * For example, consider the filter chain:
206 * filter (a) --> (b) filter (b) --> (c) filter
208 * where the letters in parenthesis indicate a list of formats supported on
209 * the input or output of the link. Suppose the lists are as follows:
214 * First, the first link's lists are merged, yielding:
215 * filter (a) --> (a) filter (a) --> (c) filter
217 * Notice that format list (b) now refers to the same list as filter list (a).
218 * Next, the lists for the second link are merged, yielding:
219 * filter (a) --> (a) filter (a) --> (a) filter
223 * Unfortunately, when the format lists at the two ends of a link are merged,
224 * we must ensure that all links which reference either pre-merge format list
225 * get updated as well. Therefore, we have the format list structure store a
226 * pointer to each of the pointers to itself.
228 typedef struct AVFilterFormats {
229 unsigned format_count; ///< number of formats
230 int64_t *formats; ///< list of media formats
232 unsigned refcount; ///< number of references to this list
233 struct AVFilterFormats ***refs; ///< references to this list
237 * Create a list of supported formats. This is intended for use in
238 * AVFilter->query_formats().
240 * @param fmts list of media formats, terminated by -1. If NULL an
241 * empty list is created.
242 * @return the format list, with no existing references
244 AVFilterFormats *avfilter_make_format_list(const int *fmts);
245 AVFilterFormats *avfilter_make_format64_list(const int64_t *fmts);
248 * Add fmt to the list of media formats contained in *avff.
249 * If *avff is NULL the function allocates the filter formats struct
250 * and puts its pointer in *avff.
252 * @return a non negative value in case of success, or a negative
253 * value corresponding to an AVERROR code in case of error
255 int avfilter_add_format(AVFilterFormats **avff, int64_t fmt);
258 * Return a list of all formats supported by FFmpeg for the given media type.
260 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
263 * Return a list of all channel layouts supported by FFmpeg.
265 AVFilterFormats *avfilter_all_channel_layouts(void);
268 * Return a format list which contains the intersection of the formats of
269 * a and b. Also, all the references of a, all the references of b, and
270 * a and b themselves will be deallocated.
272 * If a and b do not share any common formats, neither is modified, and NULL
275 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
278 * Add *ref as a new reference to formats.
279 * That is the pointers will point like in the ascii art below:
281 * |formats |<--------.
282 * | ____ | ____|___________________
284 * | |* * | | | | | | AVFilterLink
285 * | |* *--------->|*ref|
286 * | |____| | | |____|
287 * |________| |________________________
289 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
292 * If *ref is non-NULL, remove *ref as a reference to the format list
293 * it currently points to, deallocates that list if this was the last
294 * reference, and sets *ref to NULL.
297 * ________ ________ NULL
298 * |formats |<--------. |formats | ^
299 * | ____ | ____|________________ | ____ | ____|________________
300 * | |refs| | | __|_ | |refs| | | __|_
301 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
302 * | |* *--------->|*ref| | |* | | | |*ref|
303 * | |____| | | |____| | |____| | | |____|
304 * |________| |_____________________ |________| |_____________________
306 void avfilter_formats_unref(AVFilterFormats **ref);
312 * |formats |<---------. |formats |<---------.
313 * | ____ | ___|___ | ____ | ___|___
314 * | |refs| | | | | | |refs| | | | | NULL
315 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
316 * | |* * | | |_______| | |* * | | |_______| ___|___
317 * | |____| | | |____| | | | |
318 * |________| |________| |*oldref|
321 void avfilter_formats_changeref(AVFilterFormats **oldref,
322 AVFilterFormats **newref);
325 * A filter pad used for either input or output.
329 * Pad name. The name is unique among inputs and among outputs, but an
330 * input may have the same name as an output. This may be NULL if this
331 * pad has no need to ever be referenced by name.
336 * AVFilterPad type. Only video supported now, hopefully someone will
337 * add audio in the future.
339 enum AVMediaType type;
342 * Minimum required permissions on incoming buffers. Any buffer with
343 * insufficient permissions will be automatically copied by the filter
344 * system to a new buffer which provides the needed access permissions.
351 * Permissions which are not accepted on incoming buffers. Any buffer
352 * which has any of these permissions set will be automatically copied
353 * by the filter system to a new buffer which does not have those
354 * permissions. This can be used to easily disallow buffers with
362 * Callback called before passing the first slice of a new frame. If
363 * NULL, the filter layer will default to storing a reference to the
364 * picture inside the link structure.
366 * Input video pads only.
368 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
371 * Callback function to get a video buffer. If NULL, the filter system will
372 * use avfilter_default_get_video_buffer().
374 * Input video pads only.
376 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
379 * Callback function to get an audio buffer. If NULL, the filter system will
380 * use avfilter_default_get_audio_buffer().
382 * Input audio pads only.
384 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
385 enum AVSampleFormat sample_fmt, int nb_samples,
386 int64_t channel_layout, int planar);
389 * Callback called after the slices of a frame are completely sent. If
390 * NULL, the filter layer will default to releasing the reference stored
391 * in the link structure during start_frame().
393 * Input video pads only.
395 void (*end_frame)(AVFilterLink *link);
398 * Slice drawing callback. This is where a filter receives video data
399 * and should do its processing.
401 * Input video pads only.
403 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
406 * Samples filtering callback. This is where a filter receives audio data
407 * and should do its processing.
409 * Input audio pads only.
411 void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
414 * Frame poll callback. This returns the number of immediately available
415 * samples. It should return a positive value if the next request_frame()
416 * is guaranteed to return one frame (with no delay).
418 * Defaults to just calling the source poll_frame() method.
420 * Output video pads only.
422 int (*poll_frame)(AVFilterLink *link);
425 * Frame request callback. A call to this should result in at least one
426 * frame being output over the given link. This should return zero on
427 * success, and another value on error.
429 * Output video pads only.
431 int (*request_frame)(AVFilterLink *link);
434 * Link configuration callback.
436 * For output pads, this should set the link properties such as
437 * width/height. This should NOT set the format property - that is
438 * negotiated between filters by the filter system using the
439 * query_formats() callback before this function is called.
441 * For input pads, this should check the properties of the link, and update
442 * the filter's internal state as necessary.
444 * For both input and output filters, this should return zero on success,
445 * and another value on error.
447 int (*config_props)(AVFilterLink *link);
450 /** default handler for start_frame() for video inputs */
451 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
453 /** default handler for draw_slice() for video inputs */
454 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
456 /** default handler for end_frame() for video inputs */
457 void avfilter_default_end_frame(AVFilterLink *link);
459 /** default handler for filter_samples() for audio inputs */
460 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
462 /** default handler for config_props() for audio/video outputs */
463 int avfilter_default_config_output_link(AVFilterLink *link);
465 /** default handler for config_props() for audio/video inputs */
466 int avfilter_default_config_input_link (AVFilterLink *link);
468 /** default handler for get_video_buffer() for video inputs */
469 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
470 int perms, int w, int h);
472 /** default handler for get_audio_buffer() for audio inputs */
473 AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link, int perms,
474 enum AVSampleFormat sample_fmt, int nb_samples,
475 int64_t channel_layout, int planar);
478 * Helpers for query_formats() which set all links to the same list of
479 * formats/layouts. If there are no links hooked to this filter, the list
480 * of formats is freed.
482 void avfilter_set_common_pixel_formats(AVFilterContext *ctx, AVFilterFormats *formats);
483 void avfilter_set_common_sample_formats(AVFilterContext *ctx, AVFilterFormats *formats);
484 void avfilter_set_common_channel_layouts(AVFilterContext *ctx, AVFilterFormats *formats);
486 /** Default handler for query_formats() */
487 int avfilter_default_query_formats(AVFilterContext *ctx);
489 /** start_frame() handler for filters which simply pass video along */
490 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
492 /** draw_slice() handler for filters which simply pass video along */
493 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
495 /** end_frame() handler for filters which simply pass video along */
496 void avfilter_null_end_frame(AVFilterLink *link);
498 /** filter_samples() handler for filters which simply pass audio along */
499 void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
501 /** get_video_buffer() handler for filters which simply pass video along */
502 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
503 int perms, int w, int h);
505 /** get_audio_buffer() handler for filters which simply pass audio along */
506 AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link, int perms,
507 enum AVSampleFormat sample_fmt, int size,
508 int64_t channel_layout, int planar);
511 * Filter definition. This defines the pads a filter contains, and all the
512 * callback functions used to interact with the filter.
514 typedef struct AVFilter {
515 const char *name; ///< filter name
517 int priv_size; ///< size of private data to allocate for the filter
520 * Filter initialization function. Args contains the user-supplied
521 * parameters. FIXME: maybe an AVOption-based system would be better?
522 * opaque is data provided by the code requesting creation of the filter,
523 * and is used to pass data to the filter.
525 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
528 * Filter uninitialization function. Should deallocate any memory held
529 * by the filter, release any buffer references, etc. This does not need
530 * to deallocate the AVFilterContext->priv memory itself.
532 void (*uninit)(AVFilterContext *ctx);
535 * Queries formats/layouts supported by the filter and its pads, and sets
536 * the in_formats/in_chlayouts for links connected to its output pads,
537 * and out_formats/out_chlayouts for links connected to its input pads.
539 * @return zero on success, a negative value corresponding to an
540 * AVERROR code otherwise
542 int (*query_formats)(AVFilterContext *);
544 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
545 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
548 * A description for the filter. You should use the
549 * NULL_IF_CONFIG_SMALL() macro to define it.
551 const char *description;
554 /** An instance of a filter */
555 struct AVFilterContext {
556 const AVClass *av_class; ///< needed for av_log()
558 AVFilter *filter; ///< the AVFilter of which this is an instance
560 char *name; ///< name of this filter instance
562 unsigned input_count; ///< number of input pads
563 AVFilterPad *input_pads; ///< array of input pads
564 AVFilterLink **inputs; ///< array of pointers to input links
566 unsigned output_count; ///< number of output pads
567 AVFilterPad *output_pads; ///< array of output pads
568 AVFilterLink **outputs; ///< array of pointers to output links
570 void *priv; ///< private data for use by the filter
574 * A link between two filters. This contains pointers to the source and
575 * destination filters between which this link exists, and the indexes of
576 * the pads involved. In addition, this link also contains the parameters
577 * which have been negotiated and agreed upon between the filter, such as
578 * image dimensions, format, etc.
580 struct AVFilterLink {
581 AVFilterContext *src; ///< source filter
582 AVFilterPad *srcpad; ///< output pad on the source filter
584 AVFilterContext *dst; ///< dest filter
585 AVFilterPad *dstpad; ///< input pad on the dest filter
587 /** stage of the initialization of the link properties (dimensions, etc) */
589 AVLINK_UNINIT = 0, ///< not started
590 AVLINK_STARTINIT, ///< started, but incomplete
591 AVLINK_INIT ///< complete
594 enum AVMediaType type; ///< filter media type
596 /* These parameters apply only to video */
597 int w; ///< agreed upon image width
598 int h; ///< agreed upon image height
599 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
600 /* These two parameters apply only to audio */
601 int64_t channel_layout; ///< channel layout of current buffer (see libavutil/audioconvert.h)
602 int64_t sample_rate; ///< samples per second
604 int format; ///< agreed upon media format
607 * Lists of formats and channel layouts supported by the input and output
608 * filters respectively. These lists are used for negotiating the format
609 * to actually be used, which will be loaded into the format and
610 * channel_layout members, above, when chosen.
613 AVFilterFormats *in_formats;
614 AVFilterFormats *out_formats;
616 AVFilterFormats *in_chlayouts;
617 AVFilterFormats *out_chlayouts;
620 * The buffer reference currently being sent across the link by the source
621 * filter. This is used internally by the filter system to allow
622 * automatic copying of buffers which do not have sufficient permissions
623 * for the destination. This should not be accessed directly by the
626 AVFilterBufferRef *src_buf;
628 AVFilterBufferRef *cur_buf;
629 AVFilterBufferRef *out_buf;
632 * Define the time base used by the PTS of the frames/samples
633 * which will pass through this link.
634 * During the configuration stage, each filter is supposed to
635 * change only the output timebase, while the timebase of the
636 * input link is assumed to be an unchangeable property.
638 AVRational time_base;
640 struct AVFilterPool *pool;
644 * Link two filters together.
646 * @param src the source filter
647 * @param srcpad index of the output pad on the source filter
648 * @param dst the destination filter
649 * @param dstpad index of the input pad on the destination filter
650 * @return zero on success
652 int avfilter_link(AVFilterContext *src, unsigned srcpad,
653 AVFilterContext *dst, unsigned dstpad);
656 * Free the link in *link, and set its pointer to NULL.
658 void avfilter_link_free(AVFilterLink **link);
661 * Negotiate the media format, dimensions, etc of all inputs to a filter.
663 * @param filter the filter to negotiate the properties for its inputs
664 * @return zero on successful negotiation
666 int avfilter_config_links(AVFilterContext *filter);
669 * Request a picture buffer with a specific set of permissions.
671 * @param link the output link to the filter from which the buffer will
673 * @param perms the required access permissions
674 * @param w the minimum width of the buffer to allocate
675 * @param h the minimum height of the buffer to allocate
676 * @return A reference to the buffer. This must be unreferenced with
677 * avfilter_unref_buffer when you are finished with it.
679 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
683 * Create a buffer reference wrapped around an already allocated image
686 * @param data pointers to the planes of the image to reference
687 * @param linesize linesizes for the planes of the image to reference
688 * @param perms the required access permissions
689 * @param w the width of the image specified by the data and linesize arrays
690 * @param h the height of the image specified by the data and linesize arrays
691 * @param format the pixel format of the image specified by the data and linesize arrays
694 avfilter_get_video_buffer_ref_from_arrays(uint8_t * const data[4], const int linesize[4], int perms,
695 int w, int h, enum PixelFormat format);
698 * Request an audio samples buffer with a specific set of permissions.
700 * @param link the output link to the filter from which the buffer will
702 * @param perms the required access permissions
703 * @param sample_fmt the format of each sample in the buffer to allocate
704 * @param nb_samples the number of samples per channel
705 * @param channel_layout the number and type of channels per sample in the buffer to allocate
706 * @param planar audio data layout - planar or packed
707 * @return A reference to the samples. This must be unreferenced with
708 * avfilter_unref_buffer when you are finished with it.
710 AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,
711 enum AVSampleFormat sample_fmt, int nb_samples,
712 int64_t channel_layout, int planar);
715 * Create an audio buffer reference wrapped around an already
716 * allocated samples buffer.
718 * @param data pointers to the samples plane buffers
719 * @param linesize linesize for the samples plane buffers
720 * @param perms the required access permissions
721 * @param nb_samples number of samples per channel
722 * @param sample_fmt the format of each sample in the buffer to allocate
723 * @param channel_layout the channel layout of the buffer
724 * @param planar audio data layout - planar or packed
727 avfilter_get_audio_buffer_ref_from_arrays(uint8_t *data[8], int linesize[8], int perms,
728 int nb_samples, enum AVSampleFormat sample_fmt,
729 int64_t channel_layout, int planar);
732 * Request an input frame from the filter at the other end of the link.
734 * @param link the input link
735 * @return zero on success
737 int avfilter_request_frame(AVFilterLink *link);
740 * Poll a frame from the filter chain.
742 * @param link the input link
743 * @return the number of immediately available frames, a negative
744 * number in case of error
746 int avfilter_poll_frame(AVFilterLink *link);
749 * Notifie the next filter of the start of a frame.
751 * @param link the output link the frame will be sent over
752 * @param picref A reference to the frame about to be sent. The data for this
753 * frame need only be valid once draw_slice() is called for that
754 * portion. The receiving filter will free this reference when
755 * it no longer needs it.
757 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
760 * Notifie the next filter that the current frame has finished.
762 * @param link the output link the frame was sent over
764 void avfilter_end_frame(AVFilterLink *link);
767 * Send a slice to the next filter.
769 * Slices have to be provided in sequential order, either in
770 * top-bottom or bottom-top order. If slices are provided in
771 * non-sequential order the behavior of the function is undefined.
773 * @param link the output link over which the frame is being sent
774 * @param y offset in pixels from the top of the image for this slice
775 * @param h height of this slice in pixels
776 * @param slice_dir the assumed direction for sending slices,
777 * from the top slice to the bottom slice if the value is 1,
778 * from the bottom slice to the top slice if the value is -1,
779 * for other values the behavior of the function is undefined.
781 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
784 * Send a buffer of audio samples to the next filter.
786 * @param link the output link over which the audio samples are being sent
787 * @param samplesref a reference to the buffer of audio samples being sent. The
788 * receiving filter will free this reference when it no longer
789 * needs it or pass it on to the next filter.
791 void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
793 /** Initialize the filter system. Register all builtin filters. */
794 void avfilter_register_all(void);
796 /** Uninitialize the filter system. Unregister all filters. */
797 void avfilter_uninit(void);
800 * Register a filter. This is only needed if you plan to use
801 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
802 * filter can still by instantiated with avfilter_open even if it is not
805 * @param filter the filter to register
806 * @return 0 if the registration was succesfull, a negative value
809 int avfilter_register(AVFilter *filter);
812 * Get a filter definition matching the given name.
814 * @param name the filter name to find
815 * @return the filter definition, if any matching one is registered.
816 * NULL if none found.
818 AVFilter *avfilter_get_by_name(const char *name);
821 * If filter is NULL, returns a pointer to the first registered filter pointer,
822 * if filter is non-NULL, returns the next pointer after filter.
823 * If the returned pointer points to NULL, the last registered filter
824 * was already reached.
826 AVFilter **av_filter_next(AVFilter **filter);
829 * Create a filter instance.
831 * @param filter_ctx put here a pointer to the created filter context
832 * on success, NULL on failure
833 * @param filter the filter to create an instance of
834 * @param inst_name Name to give to the new instance. Can be NULL for none.
835 * @return >= 0 in case of success, a negative error code otherwise
837 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
840 * Initialize a filter.
842 * @param filter the filter to initialize
843 * @param args A string of parameters to use when initializing the filter.
844 * The format and meaning of this string varies by filter.
845 * @param opaque Any extra non-string data needed by the filter. The meaning
846 * of this parameter varies by filter.
847 * @return zero on success
849 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
852 * Free a filter context.
854 * @param filter the filter to free
856 void avfilter_free(AVFilterContext *filter);
859 * Insert a filter in the middle of an existing link.
861 * @param link the link into which the filter should be inserted
862 * @param filt the filter to be inserted
863 * @param filt_srcpad_idx the input pad on the filter to connect
864 * @param filt_dstpad_idx the output pad on the filter to connect
865 * @return zero on success
867 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
868 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
873 * @param idx Insertion point. Pad is inserted at the end if this point
874 * is beyond the end of the list of pads.
875 * @param count Pointer to the number of pads in the list
876 * @param padidx_off Offset within an AVFilterLink structure to the element
877 * to increment when inserting a new pad causes link
878 * numbering to change
879 * @param pads Pointer to the pointer to the beginning of the list of pads
880 * @param links Pointer to the pointer to the beginning of the list of links
881 * @param newpad The new pad to add. A copy is made when adding.
883 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
884 AVFilterPad **pads, AVFilterLink ***links,
885 AVFilterPad *newpad);
887 /** Insert a new input pad for the filter. */
888 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
891 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
892 &f->input_pads, &f->inputs, p);
895 /** Insert a new output pad for the filter. */
896 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
899 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
900 &f->output_pads, &f->outputs, p);
903 #endif /* AVFILTER_AVFILTER_H */