3 * Copyright (c) 2007 Bobby Bingham
5 * This file is part of Libav.
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #ifndef AVFILTER_AVFILTER_H
23 #define AVFILTER_AVFILTER_H
25 #include "libavutil/avutil.h"
26 #include "libavutil/log.h"
27 #include "libavutil/samplefmt.h"
28 #include "libavutil/pixfmt.h"
29 #include "libavutil/rational.h"
30 #include "libavcodec/avcodec.h"
34 #include "libavfilter/version.h"
37 * Return the LIBAVFILTER_VERSION_INT constant.
39 unsigned avfilter_version(void);
42 * Return the libavfilter build-time configuration.
44 const char *avfilter_configuration(void);
47 * Return the libavfilter license.
49 const char *avfilter_license(void);
52 typedef struct AVFilterContext AVFilterContext;
53 typedef struct AVFilterLink AVFilterLink;
54 typedef struct AVFilterPad AVFilterPad;
57 * A reference-counted buffer data type used by the filter system. Filters
58 * should not store pointers to this structure directly, but instead use the
59 * AVFilterBufferRef structure below.
61 typedef struct AVFilterBuffer {
62 uint8_t *data[8]; ///< buffer data for each plane/channel
63 int linesize[8]; ///< number of bytes per line
65 unsigned refcount; ///< number of references to this buffer
67 /** private data to be used by a custom free function */
70 * A pointer to the function to deallocate this buffer if the default
71 * function is not sufficient. This could, for example, add the memory
72 * back into a memory pool to be reused later without the overhead of
73 * reallocating it from scratch.
75 void (*free)(struct AVFilterBuffer *buf);
77 int format; ///< media format
78 int w, h; ///< width and height of the allocated buffer
81 * pointers to the data planes/channels.
83 * For video, this should simply point to data[].
85 * For planar audio, each channel has a separate data pointer, and
86 * linesize[0] contains the size of each channel buffer.
87 * For packed audio, there is just one data pointer, and linesize[0]
88 * contains the total size of the buffer for all channels.
90 * Note: Both data and extended_data will always be set, but for planar
91 * audio with more channels that can fit in data, extended_data must be used
92 * in order to access all channels.
94 uint8_t **extended_data;
97 #define AV_PERM_READ 0x01 ///< can read from the buffer
98 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
99 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
100 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
101 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
102 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
105 * Audio specific properties in a reference to an AVFilterBuffer. Since
106 * AVFilterBufferRef is common to different media formats, audio specific
107 * per reference properties must be separated out.
109 typedef struct AVFilterBufferRefAudioProps {
110 uint64_t channel_layout; ///< channel layout of audio buffer
111 int nb_samples; ///< number of audio samples
112 int sample_rate; ///< audio buffer sample rate
113 int planar; ///< audio buffer - planar or packed
114 } AVFilterBufferRefAudioProps;
117 * Video specific properties in a reference to an AVFilterBuffer. Since
118 * AVFilterBufferRef is common to different media formats, video specific
119 * per reference properties must be separated out.
121 typedef struct AVFilterBufferRefVideoProps {
122 int w; ///< image width
123 int h; ///< image height
124 AVRational pixel_aspect; ///< pixel aspect ratio
125 int interlaced; ///< is frame interlaced
126 int top_field_first; ///< field order
127 enum AVPictureType pict_type; ///< picture type of the frame
128 int key_frame; ///< 1 -> keyframe, 0-> not
129 } AVFilterBufferRefVideoProps;
132 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
133 * a buffer to, for example, crop image without any memcpy, the buffer origin
134 * and dimensions are per-reference properties. Linesize is also useful for
135 * image flipping, frame to field filters, etc, and so is also per-reference.
137 * TODO: add anything necessary for frame reordering
139 typedef struct AVFilterBufferRef {
140 AVFilterBuffer *buf; ///< the buffer that this is a reference to
141 uint8_t *data[8]; ///< picture/audio data for each plane
142 int linesize[8]; ///< number of bytes per line
143 int format; ///< media format
146 * presentation timestamp. The time unit may change during
147 * filtering, as it is specified in the link and the filter code
148 * may need to rescale the PTS accordingly.
151 int64_t pos; ///< byte position in stream, -1 if unknown
153 int perms; ///< permissions, see the AV_PERM_* flags
155 enum AVMediaType type; ///< media type of buffer data
156 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
157 AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
160 * pointers to the data planes/channels.
162 * For video, this should simply point to data[].
164 * For planar audio, each channel has a separate data pointer, and
165 * linesize[0] contains the size of each channel buffer.
166 * For packed audio, there is just one data pointer, and linesize[0]
167 * contains the total size of the buffer for all channels.
169 * Note: Both data and extended_data will always be set, but for planar
170 * audio with more channels that can fit in data, extended_data must be used
171 * in order to access all channels.
173 uint8_t **extended_data;
177 * Copy properties of src to dst, without copying the actual data
179 void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src);
182 * Add a new reference to a buffer.
184 * @param ref an existing reference to the buffer
185 * @param pmask a bitmask containing the allowable permissions in the new
187 * @return a new reference to the buffer with the same properties as the
188 * old, excluding any permissions denied by pmask
190 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
193 * Remove a reference to a buffer. If this is the last reference to the
194 * buffer, the buffer itself is also automatically freed.
196 * @param ref reference to the buffer, may be NULL
198 void avfilter_unref_buffer(AVFilterBufferRef *ref);
201 * A list of supported formats for one end of a filter link. This is used
202 * during the format negotiation process to try to pick the best format to
203 * use to minimize the number of necessary conversions. Each filter gives a
204 * list of the formats supported by each input and output pad. The list
205 * given for each pad need not be distinct - they may be references to the
206 * same list of formats, as is often the case when a filter supports multiple
207 * formats, but will always output the same format as it is given in input.
209 * In this way, a list of possible input formats and a list of possible
210 * output formats are associated with each link. When a set of formats is
211 * negotiated over a link, the input and output lists are merged to form a
212 * new list containing only the common elements of each list. In the case
213 * that there were no common elements, a format conversion is necessary.
214 * Otherwise, the lists are merged, and all other links which reference
215 * either of the format lists involved in the merge are also affected.
217 * For example, consider the filter chain:
218 * filter (a) --> (b) filter (b) --> (c) filter
220 * where the letters in parenthesis indicate a list of formats supported on
221 * the input or output of the link. Suppose the lists are as follows:
226 * First, the first link's lists are merged, yielding:
227 * filter (a) --> (a) filter (a) --> (c) filter
229 * Notice that format list (b) now refers to the same list as filter list (a).
230 * Next, the lists for the second link are merged, yielding:
231 * filter (a) --> (a) filter (a) --> (a) filter
235 * Unfortunately, when the format lists at the two ends of a link are merged,
236 * we must ensure that all links which reference either pre-merge format list
237 * get updated as well. Therefore, we have the format list structure store a
238 * pointer to each of the pointers to itself.
240 typedef struct AVFilterFormats {
241 unsigned format_count; ///< number of formats
242 int *formats; ///< list of media formats
244 unsigned refcount; ///< number of references to this list
245 struct AVFilterFormats ***refs; ///< references to this list
249 * Create a list of supported formats. This is intended for use in
250 * AVFilter->query_formats().
252 * @param fmts list of media formats, terminated by -1
253 * @return the format list, with no existing references
255 AVFilterFormats *avfilter_make_format_list(const int *fmts);
258 * Add fmt to the list of media formats contained in *avff.
259 * If *avff is NULL the function allocates the filter formats struct
260 * and puts its pointer in *avff.
262 * @return a non negative value in case of success, or a negative
263 * value corresponding to an AVERROR code in case of error
265 int avfilter_add_format(AVFilterFormats **avff, int fmt);
268 * Return a list of all formats supported by Libav for the given media type.
270 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
273 * Return a format list which contains the intersection of the formats of
274 * a and b. Also, all the references of a, all the references of b, and
275 * a and b themselves will be deallocated.
277 * If a and b do not share any common formats, neither is modified, and NULL
280 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
283 * Add *ref as a new reference to formats.
284 * That is the pointers will point like in the ascii art below:
286 * |formats |<--------.
287 * | ____ | ____|___________________
289 * | |* * | | | | | | AVFilterLink
290 * | |* *--------->|*ref|
291 * | |____| | | |____|
292 * |________| |________________________
294 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
297 * If *ref is non-NULL, remove *ref as a reference to the format list
298 * it currently points to, deallocates that list if this was the last
299 * reference, and sets *ref to NULL.
302 * ________ ________ NULL
303 * |formats |<--------. |formats | ^
304 * | ____ | ____|________________ | ____ | ____|________________
305 * | |refs| | | __|_ | |refs| | | __|_
306 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
307 * | |* *--------->|*ref| | |* | | | |*ref|
308 * | |____| | | |____| | |____| | | |____|
309 * |________| |_____________________ |________| |_____________________
311 void avfilter_formats_unref(AVFilterFormats **ref);
317 * |formats |<---------. |formats |<---------.
318 * | ____ | ___|___ | ____ | ___|___
319 * | |refs| | | | | | |refs| | | | | NULL
320 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
321 * | |* * | | |_______| | |* * | | |_______| ___|___
322 * | |____| | | |____| | | | |
323 * |________| |________| |*oldref|
326 void avfilter_formats_changeref(AVFilterFormats **oldref,
327 AVFilterFormats **newref);
330 * A filter pad used for either input or output.
334 * Pad name. The name is unique among inputs and among outputs, but an
335 * input may have the same name as an output. This may be NULL if this
336 * pad has no need to ever be referenced by name.
341 * AVFilterPad type. Only video supported now, hopefully someone will
342 * add audio in the future.
344 enum AVMediaType type;
347 * Minimum required permissions on incoming buffers. Any buffer with
348 * insufficient permissions will be automatically copied by the filter
349 * system to a new buffer which provides the needed access permissions.
356 * Permissions which are not accepted on incoming buffers. Any buffer
357 * which has any of these permissions set will be automatically copied
358 * by the filter system to a new buffer which does not have those
359 * permissions. This can be used to easily disallow buffers with
367 * Callback called before passing the first slice of a new frame. If
368 * NULL, the filter layer will default to storing a reference to the
369 * picture inside the link structure.
371 * Input video pads only.
373 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
376 * Callback function to get a video buffer. If NULL, the filter system will
377 * use avfilter_default_get_video_buffer().
379 * Input video pads only.
381 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
384 * Callback function to get an audio buffer. If NULL, the filter system will
385 * use avfilter_default_get_audio_buffer().
387 * Input audio pads only.
389 AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
393 * Callback called after the slices of a frame are completely sent. If
394 * NULL, the filter layer will default to releasing the reference stored
395 * in the link structure during start_frame().
397 * Input video pads only.
399 void (*end_frame)(AVFilterLink *link);
402 * Slice drawing callback. This is where a filter receives video data
403 * and should do its processing.
405 * Input video pads only.
407 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
410 * Samples filtering callback. This is where a filter receives audio data
411 * and should do its processing.
413 * Input audio pads only.
415 void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
418 * Frame poll callback. This returns the number of immediately available
419 * samples. It should return a positive value if the next request_frame()
420 * is guaranteed to return one frame (with no delay).
422 * Defaults to just calling the source poll_frame() method.
424 * Output video pads only.
426 int (*poll_frame)(AVFilterLink *link);
429 * Frame request callback. A call to this should result in at least one
430 * frame being output over the given link. This should return zero on
431 * success, and another value on error.
433 * Output video pads only.
435 int (*request_frame)(AVFilterLink *link);
438 * Link configuration callback.
440 * For output pads, this should set the link properties such as
441 * width/height. This should NOT set the format property - that is
442 * negotiated between filters by the filter system using the
443 * query_formats() callback before this function is called.
445 * For input pads, this should check the properties of the link, and update
446 * the filter's internal state as necessary.
448 * For both input and output filters, this should return zero on success,
449 * and another value on error.
451 int (*config_props)(AVFilterLink *link);
454 /** default handler for start_frame() for video inputs */
455 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
457 /** default handler for draw_slice() for video inputs */
458 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
460 /** default handler for end_frame() for video inputs */
461 void avfilter_default_end_frame(AVFilterLink *link);
463 /** default handler for config_props() for audio/video outputs */
464 int avfilter_default_config_output_link(AVFilterLink *link);
466 /** default handler for get_video_buffer() for video inputs */
467 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
468 int perms, int w, int h);
471 * A helper for query_formats() which sets all links to the same list of
472 * formats. If there are no links hooked to this filter, the list of formats is
475 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
477 /** Default handler for query_formats() */
478 int avfilter_default_query_formats(AVFilterContext *ctx);
480 /** start_frame() handler for filters which simply pass video along */
481 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
483 /** draw_slice() handler for filters which simply pass video along */
484 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
486 /** end_frame() handler for filters which simply pass video along */
487 void avfilter_null_end_frame(AVFilterLink *link);
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);
494 * Filter definition. This defines the pads a filter contains, and all the
495 * callback functions used to interact with the filter.
497 typedef struct AVFilter {
498 const char *name; ///< filter name
500 int priv_size; ///< size of private data to allocate for the filter
503 * Filter initialization function. Args contains the user-supplied
504 * parameters. FIXME: maybe an AVOption-based system would be better?
505 * opaque is data provided by the code requesting creation of the filter,
506 * and is used to pass data to the filter.
508 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
511 * Filter uninitialization function. Should deallocate any memory held
512 * by the filter, release any buffer references, etc. This does not need
513 * to deallocate the AVFilterContext->priv memory itself.
515 void (*uninit)(AVFilterContext *ctx);
518 * Queries formats supported by the filter and its pads, and sets the
519 * in_formats for links connected to its output pads, and out_formats
520 * for links connected to its input pads.
522 * @return zero on success, a negative value corresponding to an
523 * AVERROR code otherwise
525 int (*query_formats)(AVFilterContext *);
527 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
528 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
531 * A description for the filter. You should use the
532 * NULL_IF_CONFIG_SMALL() macro to define it.
534 const char *description;
537 /** An instance of a filter */
538 struct AVFilterContext {
539 const AVClass *av_class; ///< needed for av_log()
541 AVFilter *filter; ///< the AVFilter of which this is an instance
543 char *name; ///< name of this filter instance
545 unsigned input_count; ///< number of input pads
546 AVFilterPad *input_pads; ///< array of input pads
547 AVFilterLink **inputs; ///< array of pointers to input links
549 unsigned output_count; ///< number of output pads
550 AVFilterPad *output_pads; ///< array of output pads
551 AVFilterLink **outputs; ///< array of pointers to output links
553 void *priv; ///< private data for use by the filter
557 * A link between two filters. This contains pointers to the source and
558 * destination filters between which this link exists, and the indexes of
559 * the pads involved. In addition, this link also contains the parameters
560 * which have been negotiated and agreed upon between the filter, such as
561 * image dimensions, format, etc.
563 struct AVFilterLink {
564 AVFilterContext *src; ///< source filter
565 AVFilterPad *srcpad; ///< output pad on the source filter
567 AVFilterContext *dst; ///< dest filter
568 AVFilterPad *dstpad; ///< input pad on the dest filter
570 /** stage of the initialization of the link properties (dimensions, etc) */
572 AVLINK_UNINIT = 0, ///< not started
573 AVLINK_STARTINIT, ///< started, but incomplete
574 AVLINK_INIT ///< complete
577 enum AVMediaType type; ///< filter media type
579 /* These parameters apply only to video */
580 int w; ///< agreed upon image width
581 int h; ///< agreed upon image height
582 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
583 /* These two parameters apply only to audio */
584 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/audioconvert.h)
585 #if FF_API_SAMPLERATE64
586 int64_t sample_rate; ///< samples per second
588 int sample_rate; ///< samples per second
591 int format; ///< agreed upon media format
594 * Lists of formats supported by the input and output filters respectively.
595 * These lists are used for negotiating the format to actually be used,
596 * which will be loaded into the format member, above, when chosen.
598 AVFilterFormats *in_formats;
599 AVFilterFormats *out_formats;
602 * The buffer reference currently being sent across the link by the source
603 * filter. This is used internally by the filter system to allow
604 * automatic copying of buffers which do not have sufficient permissions
605 * for the destination. This should not be accessed directly by the
608 AVFilterBufferRef *src_buf;
610 AVFilterBufferRef *cur_buf;
611 AVFilterBufferRef *out_buf;
614 * Define the time base used by the PTS of the frames/samples
615 * which will pass through this link.
616 * During the configuration stage, each filter is supposed to
617 * change only the output timebase, while the timebase of the
618 * input link is assumed to be an unchangeable property.
620 AVRational time_base;
622 /*****************************************************************
623 * All fields below this line are not part of the public API. They
624 * may not be used outside of libavfilter and can be changed and
626 * New public fields should be added right above.
627 *****************************************************************
630 * Lists of channel layouts and sample rates used for automatic
633 AVFilterFormats *in_samplerates;
634 AVFilterFormats *out_samplerates;
635 struct AVFilterChannelLayouts *in_channel_layouts;
636 struct AVFilterChannelLayouts *out_channel_layouts;
640 * Link two filters together.
642 * @param src the source filter
643 * @param srcpad index of the output pad on the source filter
644 * @param dst the destination filter
645 * @param dstpad index of the input pad on the destination filter
646 * @return zero on success
648 int avfilter_link(AVFilterContext *src, unsigned srcpad,
649 AVFilterContext *dst, unsigned dstpad);
652 * Negotiate the media format, dimensions, etc of all inputs to a filter.
654 * @param filter the filter to negotiate the properties for its inputs
655 * @return zero on successful negotiation
657 int avfilter_config_links(AVFilterContext *filter);
660 * Request a picture buffer with a specific set of permissions.
662 * @param link the output link to the filter from which the buffer will
664 * @param perms the required access permissions
665 * @param w the minimum width of the buffer to allocate
666 * @param h the minimum height of the buffer to allocate
667 * @return A reference to the buffer. This must be unreferenced with
668 * avfilter_unref_buffer when you are finished with it.
670 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
674 * Create a buffer reference wrapped around an already allocated image
677 * @param data pointers to the planes of the image to reference
678 * @param linesize linesizes for the planes of the image to reference
679 * @param perms the required access permissions
680 * @param w the width of the image specified by the data and linesize arrays
681 * @param h the height of the image specified by the data and linesize arrays
682 * @param format the pixel format of the image specified by the data and linesize arrays
685 avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int perms,
686 int w, int h, enum PixelFormat format);
689 * Create an audio buffer reference wrapped around an already
690 * allocated samples buffer.
692 * @param data pointers to the samples plane buffers
693 * @param linesize linesize for the samples plane buffers
694 * @param perms the required access permissions
695 * @param nb_samples number of samples per channel
696 * @param sample_fmt the format of each sample in the buffer to allocate
697 * @param channel_layout the channel layout of the buffer
699 AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
703 enum AVSampleFormat sample_fmt,
704 uint64_t channel_layout);
707 * Request an input frame from the filter at the other end of the link.
709 * @param link the input link
710 * @return zero on success
712 int avfilter_request_frame(AVFilterLink *link);
715 * Poll a frame from the filter chain.
717 * @param link the input link
718 * @return the number of immediately available frames, a negative
719 * number in case of error
721 int avfilter_poll_frame(AVFilterLink *link);
724 * Notify the next filter of the start of a frame.
726 * @param link the output link the frame will be sent over
727 * @param picref A reference to the frame about to be sent. The data for this
728 * frame need only be valid once draw_slice() is called for that
729 * portion. The receiving filter will free this reference when
730 * it no longer needs it.
732 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
735 * Notifie the next filter that the current frame has finished.
737 * @param link the output link the frame was sent over
739 void avfilter_end_frame(AVFilterLink *link);
742 * Send a slice to the next filter.
744 * Slices have to be provided in sequential order, either in
745 * top-bottom or bottom-top order. If slices are provided in
746 * non-sequential order the behavior of the function is undefined.
748 * @param link the output link over which the frame is being sent
749 * @param y offset in pixels from the top of the image for this slice
750 * @param h height of this slice in pixels
751 * @param slice_dir the assumed direction for sending slices,
752 * from the top slice to the bottom slice if the value is 1,
753 * from the bottom slice to the top slice if the value is -1,
754 * for other values the behavior of the function is undefined.
756 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
758 /** Initialize the filter system. Register all builtin filters. */
759 void avfilter_register_all(void);
761 /** Uninitialize the filter system. Unregister all filters. */
762 void avfilter_uninit(void);
765 * Register a filter. This is only needed if you plan to use
766 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
767 * filter can still by instantiated with avfilter_open even if it is not
770 * @param filter the filter to register
771 * @return 0 if the registration was succesfull, a negative value
774 int avfilter_register(AVFilter *filter);
777 * Get a filter definition matching the given name.
779 * @param name the filter name to find
780 * @return the filter definition, if any matching one is registered.
781 * NULL if none found.
783 AVFilter *avfilter_get_by_name(const char *name);
786 * If filter is NULL, returns a pointer to the first registered filter pointer,
787 * if filter is non-NULL, returns the next pointer after filter.
788 * If the returned pointer points to NULL, the last registered filter
789 * was already reached.
791 AVFilter **av_filter_next(AVFilter **filter);
794 * Create a filter instance.
796 * @param filter_ctx put here a pointer to the created filter context
797 * on success, NULL on failure
798 * @param filter the filter to create an instance of
799 * @param inst_name Name to give to the new instance. Can be NULL for none.
800 * @return >= 0 in case of success, a negative error code otherwise
802 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
805 * Initialize a filter.
807 * @param filter the filter to initialize
808 * @param args A string of parameters to use when initializing the filter.
809 * The format and meaning of this string varies by filter.
810 * @param opaque Any extra non-string data needed by the filter. The meaning
811 * of this parameter varies by filter.
812 * @return zero on success
814 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
817 * Free a filter context.
819 * @param filter the filter to free
821 void avfilter_free(AVFilterContext *filter);
824 * Insert a filter in the middle of an existing link.
826 * @param link the link into which the filter should be inserted
827 * @param filt the filter to be inserted
828 * @param filt_srcpad_idx the input pad on the filter to connect
829 * @param filt_dstpad_idx the output pad on the filter to connect
830 * @return zero on success
832 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
833 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
838 * @param idx Insertion point. Pad is inserted at the end if this point
839 * is beyond the end of the list of pads.
840 * @param count Pointer to the number of pads in the list
841 * @param padidx_off Offset within an AVFilterLink structure to the element
842 * to increment when inserting a new pad causes link
843 * numbering to change
844 * @param pads Pointer to the pointer to the beginning of the list of pads
845 * @param links Pointer to the pointer to the beginning of the list of links
846 * @param newpad The new pad to add. A copy is made when adding.
848 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
849 AVFilterPad **pads, AVFilterLink ***links,
850 AVFilterPad *newpad);
852 /** Insert a new input pad for the filter. */
853 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
856 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
857 &f->input_pads, &f->inputs, p);
860 /** Insert a new output pad for the filter. */
861 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
864 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
865 &f->output_pads, &f->outputs, p);
869 * Copy the frame properties of src to dst, without copying the actual
872 * @return 0 on success, a negative number on error.
874 int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
877 * Copy the frame properties and data pointers of src to dst, without copying
880 * @return 0 on success, a negative number on error.
882 int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src);
884 #endif /* AVFILTER_AVFILTER_H */