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 "libavcore/avcore.h"
27 #include "libavcore/samplefmt.h"
29 #define LIBAVFILTER_VERSION_MAJOR 1
30 #define LIBAVFILTER_VERSION_MINOR 72
31 #define LIBAVFILTER_VERSION_MICRO 0
33 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
34 LIBAVFILTER_VERSION_MINOR, \
35 LIBAVFILTER_VERSION_MICRO)
36 #define LIBAVFILTER_VERSION AV_VERSION(LIBAVFILTER_VERSION_MAJOR, \
37 LIBAVFILTER_VERSION_MINOR, \
38 LIBAVFILTER_VERSION_MICRO)
39 #define LIBAVFILTER_BUILD LIBAVFILTER_VERSION_INT
44 * Return the LIBAVFILTER_VERSION_INT constant.
46 unsigned avfilter_version(void);
49 * Return the libavfilter build-time configuration.
51 const char *avfilter_configuration(void);
54 * Return the libavfilter license.
56 const char *avfilter_license(void);
59 typedef struct AVFilterContext AVFilterContext;
60 typedef struct AVFilterLink AVFilterLink;
61 typedef struct AVFilterPad AVFilterPad;
64 * A reference-counted buffer data type used by the filter system. Filters
65 * should not store pointers to this structure directly, but instead use the
66 * AVFilterBufferRef structure below.
68 typedef struct AVFilterBuffer {
69 uint8_t *data[8]; ///< buffer data for each plane/channel
70 int linesize[8]; ///< number of bytes per line
72 unsigned refcount; ///< number of references to this buffer
74 /** private data to be used by a custom free function */
77 * A pointer to the function to deallocate this buffer if the default
78 * function is not sufficient. This could, for example, add the memory
79 * back into a memory pool to be reused later without the overhead of
80 * reallocating it from scratch.
82 void (*free)(struct AVFilterBuffer *buf);
85 #define AV_PERM_READ 0x01 ///< can read from the buffer
86 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
87 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
88 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
89 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
90 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
93 * Audio specific properties in a reference to an AVFilterBuffer. Since
94 * AVFilterBufferRef is common to different media formats, audio specific
95 * per reference properties must be separated out.
97 typedef struct AVFilterBufferRefAudioProps {
98 int64_t channel_layout; ///< channel layout of audio buffer
99 int samples_nb; ///< number of audio samples
100 int size; ///< audio buffer size
101 uint32_t sample_rate; ///< audio buffer sample rate
102 int planar; ///< audio buffer - planar or packed
103 } AVFilterBufferRefAudioProps;
106 * Video specific properties in a reference to an AVFilterBuffer. Since
107 * AVFilterBufferRef is common to different media formats, video specific
108 * per reference properties must be separated out.
110 typedef struct AVFilterBufferRefVideoProps {
111 int w; ///< image width
112 int h; ///< image height
113 AVRational pixel_aspect; ///< pixel aspect ratio
114 int interlaced; ///< is frame interlaced
115 int top_field_first; ///< field order
116 } AVFilterBufferRefVideoProps;
119 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
120 * a buffer to, for example, crop image without any memcpy, the buffer origin
121 * and dimensions are per-reference properties. Linesize is also useful for
122 * image flipping, frame to field filters, etc, and so is also per-reference.
124 * TODO: add anything necessary for frame reordering
126 typedef struct AVFilterBufferRef {
127 AVFilterBuffer *buf; ///< the buffer that this is a reference to
128 uint8_t *data[8]; ///< picture/audio data for each plane
129 int linesize[8]; ///< number of bytes per line
130 int format; ///< media format
133 * presentation timestamp. The time unit may change during
134 * filtering, as it is specified in the link and the filter code
135 * may need to rescale the PTS accordingly.
138 int64_t pos; ///< byte position in stream, -1 if unknown
140 int perms; ///< permissions, see the AV_PERM_* flags
142 enum AVMediaType type; ///< media type of buffer data
143 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
144 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
148 * Copy properties of src to dst, without copying the actual data
150 static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
152 // copy common properties
157 case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
158 case AVMEDIA_TYPE_AUDIO: *dst->audio = *src->audio; break;
163 * Add a new reference to a buffer.
165 * @param ref an existing reference to the buffer
166 * @param pmask a bitmask containing the allowable permissions in the new
168 * @return a new reference to the buffer with the same properties as the
169 * old, excluding any permissions denied by pmask
171 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
174 * Remove a reference to a buffer. If this is the last reference to the
175 * buffer, the buffer itself is also automatically freed.
177 * @param ref reference to the buffer
179 void avfilter_unref_buffer(AVFilterBufferRef *ref);
182 * A list of supported formats for one end of a filter link. This is used
183 * during the format negotiation process to try to pick the best format to
184 * use to minimize the number of necessary conversions. Each filter gives a
185 * list of the formats supported by each input and output pad. The list
186 * given for each pad need not be distinct - they may be references to the
187 * same list of formats, as is often the case when a filter supports multiple
188 * formats, but will always output the same format as it is given in input.
190 * In this way, a list of possible input formats and a list of possible
191 * output formats are associated with each link. When a set of formats is
192 * negotiated over a link, the input and output lists are merged to form a
193 * new list containing only the common elements of each list. In the case
194 * that there were no common elements, a format conversion is necessary.
195 * Otherwise, the lists are merged, and all other links which reference
196 * either of the format lists involved in the merge are also affected.
198 * For example, consider the filter chain:
199 * filter (a) --> (b) filter (b) --> (c) filter
201 * where the letters in parenthesis indicate a list of formats supported on
202 * the input or output of the link. Suppose the lists are as follows:
207 * First, the first link's lists are merged, yielding:
208 * filter (a) --> (a) filter (a) --> (c) filter
210 * Notice that format list (b) now refers to the same list as filter list (a).
211 * Next, the lists for the second link are merged, yielding:
212 * filter (a) --> (a) filter (a) --> (a) filter
216 * Unfortunately, when the format lists at the two ends of a link are merged,
217 * we must ensure that all links which reference either pre-merge format list
218 * get updated as well. Therefore, we have the format list structure store a
219 * pointer to each of the pointers to itself.
221 typedef struct AVFilterFormats {
222 unsigned format_count; ///< number of formats
223 int *formats; ///< list of media formats
225 unsigned refcount; ///< number of references to this list
226 struct AVFilterFormats ***refs; ///< references to this list
230 * Create a list of supported formats. This is intended for use in
231 * AVFilter->query_formats().
233 * @param fmts list of media formats, terminated by -1
234 * @return the format list, with no existing references
236 AVFilterFormats *avfilter_make_format_list(const int *fmts);
239 * Add fmt to the list of media formats contained in *avff.
240 * If *avff is NULL the function allocates the filter formats struct
241 * and puts its pointer in *avff.
243 * @return a non negative value in case of success, or a negative
244 * value corresponding to an AVERROR code in case of error
246 int avfilter_add_format(AVFilterFormats **avff, int fmt);
249 * Return a list of all formats supported by FFmpeg for the given media type.
251 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
254 * Return a format list which contains the intersection of the formats of
255 * a and b. Also, all the references of a, all the references of b, and
256 * a and b themselves will be deallocated.
258 * If a and b do not share any common formats, neither is modified, and NULL
261 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
264 * Add *ref as a new reference to formats.
265 * That is the pointers will point like in the ascii art below:
267 * |formats |<--------.
268 * | ____ | ____|___________________
270 * | |* * | | | | | | AVFilterLink
271 * | |* *--------->|*ref|
272 * | |____| | | |____|
273 * |________| |________________________
275 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
278 * If *ref is non-NULL, remove *ref as a reference to the format list
279 * it currently points to, deallocates that list if this was the last
280 * reference, and sets *ref to NULL.
283 * ________ ________ NULL
284 * |formats |<--------. |formats | ^
285 * | ____ | ____|________________ | ____ | ____|________________
286 * | |refs| | | __|_ | |refs| | | __|_
287 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
288 * | |* *--------->|*ref| | |* | | | |*ref|
289 * | |____| | | |____| | |____| | | |____|
290 * |________| |_____________________ |________| |_____________________
292 void avfilter_formats_unref(AVFilterFormats **ref);
298 * |formats |<---------. |formats |<---------.
299 * | ____ | ___|___ | ____ | ___|___
300 * | |refs| | | | | | |refs| | | | | NULL
301 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
302 * | |* * | | |_______| | |* * | | |_______| ___|___
303 * | |____| | | |____| | | | |
304 * |________| |________| |*oldref|
307 void avfilter_formats_changeref(AVFilterFormats **oldref,
308 AVFilterFormats **newref);
311 * A filter pad used for either input or output.
315 * Pad name. The name is unique among inputs and among outputs, but an
316 * input may have the same name as an output. This may be NULL if this
317 * pad has no need to ever be referenced by name.
322 * AVFilterPad type. Only video supported now, hopefully someone will
323 * add audio in the future.
325 enum AVMediaType type;
328 * Minimum required permissions on incoming buffers. Any buffer with
329 * insufficient permissions will be automatically copied by the filter
330 * system to a new buffer which provides the needed access permissions.
337 * Permissions which are not accepted on incoming buffers. Any buffer
338 * which has any of these permissions set will be automatically copied
339 * by the filter system to a new buffer which does not have those
340 * permissions. This can be used to easily disallow buffers with
348 * Callback called before passing the first slice of a new frame. If
349 * NULL, the filter layer will default to storing a reference to the
350 * picture inside the link structure.
352 * Input video pads only.
354 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
357 * Callback function to get a video buffer. If NULL, the filter system will
358 * use avfilter_default_get_video_buffer().
360 * Input video pads only.
362 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
365 * Callback function to get an audio buffer. If NULL, the filter system will
366 * use avfilter_default_get_audio_buffer().
368 * Input audio pads only.
370 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
371 enum AVSampleFormat sample_fmt, int size,
372 int64_t channel_layout, int planar);
375 * Callback called after the slices of a frame are completely sent. If
376 * NULL, the filter layer will default to releasing the reference stored
377 * in the link structure during start_frame().
379 * Input video pads only.
381 void (*end_frame)(AVFilterLink *link);
384 * Slice drawing callback. This is where a filter receives video data
385 * and should do its processing.
387 * Input video pads only.
389 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
392 * Samples filtering callback. This is where a filter receives audio data
393 * and should do its processing.
395 * Input audio pads only.
397 void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
400 * Frame poll callback. This returns the number of immediately available
401 * samples. It should return a positive value if the next request_frame()
402 * is guaranteed to return one frame (with no delay).
404 * Defaults to just calling the source poll_frame() method.
406 * Output video pads only.
408 int (*poll_frame)(AVFilterLink *link);
411 * Frame request callback. A call to this should result in at least one
412 * frame being output over the given link. This should return zero on
413 * success, and another value on error.
415 * Output video pads only.
417 int (*request_frame)(AVFilterLink *link);
420 * Link configuration callback.
422 * For output pads, this should set the link properties such as
423 * width/height. This should NOT set the format property - that is
424 * negotiated between filters by the filter system using the
425 * query_formats() callback before this function is called.
427 * For input pads, this should check the properties of the link, and update
428 * the filter's internal state as necessary.
430 * For both input and output filters, this should return zero on success,
431 * and another value on error.
433 int (*config_props)(AVFilterLink *link);
436 /** default handler for start_frame() for video inputs */
437 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
439 /** default handler for draw_slice() for video inputs */
440 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
442 /** default handler for end_frame() for video inputs */
443 void avfilter_default_end_frame(AVFilterLink *link);
445 /** default handler for filter_samples() for audio inputs */
446 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
448 /** default handler for config_props() for audio/video outputs */
449 int avfilter_default_config_output_link(AVFilterLink *link);
451 /** default handler for config_props() for audio/video inputs */
452 int avfilter_default_config_input_link (AVFilterLink *link);
454 /** default handler for get_video_buffer() for video inputs */
455 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
456 int perms, int w, int h);
458 /** default handler for get_audio_buffer() for audio inputs */
459 AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link, int perms,
460 enum AVSampleFormat sample_fmt, int size,
461 int64_t channel_layout, int planar);
464 * A helper for query_formats() which sets all links to the same list of
465 * formats. If there are no links hooked to this filter, the list of formats is
468 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
470 /** Default handler for query_formats() */
471 int avfilter_default_query_formats(AVFilterContext *ctx);
473 /** start_frame() handler for filters which simply pass video along */
474 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
476 /** draw_slice() handler for filters which simply pass video along */
477 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
479 /** end_frame() handler for filters which simply pass video along */
480 void avfilter_null_end_frame(AVFilterLink *link);
482 /** filter_samples() handler for filters which simply pass audio along */
483 void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
485 /** get_video_buffer() handler for filters which simply pass video along */
486 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
487 int perms, int w, int h);
489 /** get_audio_buffer() handler for filters which simply pass audio along */
490 AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link, int perms,
491 enum AVSampleFormat sample_fmt, int size,
492 int64_t channel_layout, int planar);
495 * Filter definition. This defines the pads a filter contains, and all the
496 * callback functions used to interact with the filter.
498 typedef struct AVFilter {
499 const char *name; ///< filter name
501 int priv_size; ///< size of private data to allocate for the filter
504 * Filter initialization function. Args contains the user-supplied
505 * parameters. FIXME: maybe an AVOption-based system would be better?
506 * opaque is data provided by the code requesting creation of the filter,
507 * and is used to pass data to the filter.
509 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
512 * Filter uninitialization function. Should deallocate any memory held
513 * by the filter, release any buffer references, etc. This does not need
514 * to deallocate the AVFilterContext->priv memory itself.
516 void (*uninit)(AVFilterContext *ctx);
519 * Queries formats supported by the filter and its pads, and sets the
520 * in_formats for links connected to its output pads, and out_formats
521 * for links connected to its input pads.
523 * @return zero on success, a negative value corresponding to an
524 * AVERROR code otherwise
526 int (*query_formats)(AVFilterContext *);
528 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
529 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
532 * A description for the filter. You should use the
533 * NULL_IF_CONFIG_SMALL() macro to define it.
535 const char *description;
538 /** An instance of a filter */
539 struct AVFilterContext {
540 const AVClass *av_class; ///< needed for av_log()
542 AVFilter *filter; ///< the AVFilter of which this is an instance
544 char *name; ///< name of this filter instance
546 unsigned input_count; ///< number of input pads
547 AVFilterPad *input_pads; ///< array of input pads
548 AVFilterLink **inputs; ///< array of pointers to input links
550 unsigned output_count; ///< number of output pads
551 AVFilterPad *output_pads; ///< array of output pads
552 AVFilterLink **outputs; ///< array of pointers to output links
554 void *priv; ///< private data for use by the filter
558 * A link between two filters. This contains pointers to the source and
559 * destination filters between which this link exists, and the indexes of
560 * the pads involved. In addition, this link also contains the parameters
561 * which have been negotiated and agreed upon between the filter, such as
562 * image dimensions, format, etc.
564 struct AVFilterLink {
565 AVFilterContext *src; ///< source filter
566 AVFilterPad *srcpad; ///< output pad on the source filter
568 AVFilterContext *dst; ///< dest filter
569 AVFilterPad *dstpad; ///< input pad on the dest filter
571 /** stage of the initialization of the link properties (dimensions, etc) */
573 AVLINK_UNINIT = 0, ///< not started
574 AVLINK_STARTINIT, ///< started, but incomplete
575 AVLINK_INIT ///< complete
578 enum AVMediaType type; ///< filter media type
580 /* These two parameters apply only to video */
581 int w; ///< agreed upon image width
582 int h; ///< agreed upon image height
583 /* These two parameters apply only to audio */
584 int64_t channel_layout; ///< channel layout of current buffer (see libavcore/audioconvert.h)
585 int64_t sample_rate; ///< samples per second
587 int format; ///< agreed upon media format
590 * Lists of formats supported by the input and output filters respectively.
591 * These lists are used for negotiating the format to actually be used,
592 * which will be loaded into the format member, above, when chosen.
594 AVFilterFormats *in_formats;
595 AVFilterFormats *out_formats;
598 * The buffer reference currently being sent across the link by the source
599 * filter. This is used internally by the filter system to allow
600 * automatic copying of buffers which do not have sufficient permissions
601 * for the destination. This should not be accessed directly by the
604 AVFilterBufferRef *src_buf;
606 AVFilterBufferRef *cur_buf;
607 AVFilterBufferRef *out_buf;
610 * Define the time base used by the PTS of the frames/samples
611 * which will pass through this link.
612 * During the configuration stage, each filter is supposed to
613 * change only the output timebase, while the timebase of the
614 * input link is assumed to be an unchangeable property.
616 AVRational time_base;
620 * Link two filters together.
622 * @param src the source filter
623 * @param srcpad index of the output pad on the source filter
624 * @param dst the destination filter
625 * @param dstpad index of the input pad on the destination filter
626 * @return zero on success
628 int avfilter_link(AVFilterContext *src, unsigned srcpad,
629 AVFilterContext *dst, unsigned dstpad);
632 * Negotiate the media format, dimensions, etc of all inputs to a filter.
634 * @param filter the filter to negotiate the properties for its inputs
635 * @return zero on successful negotiation
637 int avfilter_config_links(AVFilterContext *filter);
640 * Request a picture buffer with a specific set of permissions.
642 * @param link the output link to the filter from which the buffer will
644 * @param perms the required access permissions
645 * @param w the minimum width of the buffer to allocate
646 * @param h the minimum height of the buffer to allocate
647 * @return A reference to the buffer. This must be unreferenced with
648 * avfilter_unref_buffer when you are finished with it.
650 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
654 * Create a buffer reference wrapped around an already allocated image
657 * @param data pointers to the planes of the image to reference
658 * @param linesize linesizes for the planes of the image to reference
659 * @param perms the required access permissions
660 * @param w the width of the image specified by the data and linesize arrays
661 * @param h the height of the image specified by the data and linesize arrays
662 * @param format the pixel format of the image specified by the data and linesize arrays
665 avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int perms,
666 int w, int h, enum PixelFormat format);
669 * Request an audio samples 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 sample_fmt the format of each sample in the buffer to allocate
675 * @param size the buffer size in bytes
676 * @param channel_layout the number and type of channels per sample in the buffer to allocate
677 * @param planar audio data layout - planar or packed
678 * @return A reference to the samples. This must be unreferenced with
679 * avfilter_unref_buffer when you are finished with it.
681 AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,
682 enum AVSampleFormat sample_fmt, int size,
683 int64_t channel_layout, int planar);
686 * Request an input frame from the filter at the other end of the link.
688 * @param link the input link
689 * @return zero on success
691 int avfilter_request_frame(AVFilterLink *link);
694 * Poll a frame from the filter chain.
696 * @param link the input link
697 * @return the number of immediately available frames, a negative
698 * number in case of error
700 int avfilter_poll_frame(AVFilterLink *link);
703 * Notifie the next filter of the start of a frame.
705 * @param link the output link the frame will be sent over
706 * @param picref A reference to the frame about to be sent. The data for this
707 * frame need only be valid once draw_slice() is called for that
708 * portion. The receiving filter will free this reference when
709 * it no longer needs it.
711 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
714 * Notifie the next filter that the current frame has finished.
716 * @param link the output link the frame was sent over
718 void avfilter_end_frame(AVFilterLink *link);
721 * Send a slice to the next filter.
723 * Slices have to be provided in sequential order, either in
724 * top-bottom or bottom-top order. If slices are provided in
725 * non-sequential order the behavior of the function is undefined.
727 * @param link the output link over which the frame is being sent
728 * @param y offset in pixels from the top of the image for this slice
729 * @param h height of this slice in pixels
730 * @param slice_dir the assumed direction for sending slices,
731 * from the top slice to the bottom slice if the value is 1,
732 * from the bottom slice to the top slice if the value is -1,
733 * for other values the behavior of the function is undefined.
735 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
738 * Send a buffer of audio samples to the next filter.
740 * @param link the output link over which the audio samples are being sent
741 * @param samplesref a reference to the buffer of audio samples being sent. The
742 * receiving filter will free this reference when it no longer
743 * needs it or pass it on to the next filter.
745 void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
747 /** Initialize the filter system. Register all builtin filters. */
748 void avfilter_register_all(void);
750 /** Uninitialize the filter system. Unregister all filters. */
751 void avfilter_uninit(void);
754 * Register a filter. This is only needed if you plan to use
755 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
756 * filter can still by instantiated with avfilter_open even if it is not
759 * @param filter the filter to register
760 * @return 0 if the registration was succesfull, a negative value
763 int avfilter_register(AVFilter *filter);
766 * Get a filter definition matching the given name.
768 * @param name the filter name to find
769 * @return the filter definition, if any matching one is registered.
770 * NULL if none found.
772 AVFilter *avfilter_get_by_name(const char *name);
775 * If filter is NULL, returns a pointer to the first registered filter pointer,
776 * if filter is non-NULL, returns the next pointer after filter.
777 * If the returned pointer points to NULL, the last registered filter
778 * was already reached.
780 AVFilter **av_filter_next(AVFilter **filter);
783 * Create a filter instance.
785 * @param filter_ctx put here a pointer to the created filter context
786 * on success, NULL on failure
787 * @param filter the filter to create an instance of
788 * @param inst_name Name to give to the new instance. Can be NULL for none.
789 * @return >= 0 in case of success, a negative error code otherwise
791 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
794 * Initialize a filter.
796 * @param filter the filter to initialize
797 * @param args A string of parameters to use when initializing the filter.
798 * The format and meaning of this string varies by filter.
799 * @param opaque Any extra non-string data needed by the filter. The meaning
800 * of this parameter varies by filter.
801 * @return zero on success
803 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
806 * Free a filter context.
808 * @param filter the filter to free
810 void avfilter_free(AVFilterContext *filter);
813 * Insert a filter in the middle of an existing link.
815 * @param link the link into which the filter should be inserted
816 * @param filt the filter to be inserted
817 * @param filt_srcpad_idx the input pad on the filter to connect
818 * @param filt_dstpad_idx the output pad on the filter to connect
819 * @return zero on success
821 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
822 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
827 * @param idx Insertion point. Pad is inserted at the end if this point
828 * is beyond the end of the list of pads.
829 * @param count Pointer to the number of pads in the list
830 * @param padidx_off Offset within an AVFilterLink structure to the element
831 * to increment when inserting a new pad causes link
832 * numbering to change
833 * @param pads Pointer to the pointer to the beginning of the list of pads
834 * @param links Pointer to the pointer to the beginning of the list of links
835 * @param newpad The new pad to add. A copy is made when adding.
837 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
838 AVFilterPad **pads, AVFilterLink ***links,
839 AVFilterPad *newpad);
841 /** Insert a new input pad for the filter. */
842 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
845 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
846 &f->input_pads, &f->inputs, p);
849 /** Insert a new output pad for the filter. */
850 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
853 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
854 &f->output_pads, &f->outputs, p);
857 #endif /* AVFILTER_AVFILTER_H */