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avfilter.h
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1 /*
2  * filter layer
3  * Copyright (c) 2007 Bobby Bingham
4  *
5  * This file is part of FFmpeg.
6  *
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.
11  *
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.
16  *
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
20  */
21 
22 #ifndef AVFILTER_AVFILTER_H
23 #define AVFILTER_AVFILTER_H
24 
25 /**
26  * @file
27  * @ingroup lavfi
28  * Main libavfilter public API header
29  */
30 
31 /**
32  * @defgroup lavfi Libavfilter - graph-based frame editing library
33  * @{
34  */
35 
36 #include <stddef.h>
37 
38 #include "libavutil/attributes.h"
39 #include "libavutil/avutil.h"
40 #include "libavutil/dict.h"
41 #include "libavutil/frame.h"
42 #include "libavutil/log.h"
43 #include "libavutil/samplefmt.h"
44 #include "libavutil/pixfmt.h"
45 #include "libavutil/rational.h"
46 
47 #include "libavfilter/version.h"
48 
49 /**
50  * Return the LIBAVFILTER_VERSION_INT constant.
51  */
52 unsigned avfilter_version(void);
53 
54 /**
55  * Return the libavfilter build-time configuration.
56  */
57 const char *avfilter_configuration(void);
58 
59 /**
60  * Return the libavfilter license.
61  */
62 const char *avfilter_license(void);
63 
64 typedef struct AVFilterContext AVFilterContext;
65 typedef struct AVFilterLink AVFilterLink;
66 typedef struct AVFilterPad AVFilterPad;
67 typedef struct AVFilterFormats AVFilterFormats;
68 
69 #if FF_API_AVFILTERBUFFER
70 /**
71  * A reference-counted buffer data type used by the filter system. Filters
72  * should not store pointers to this structure directly, but instead use the
73  * AVFilterBufferRef structure below.
74  */
75 typedef struct AVFilterBuffer {
76  uint8_t *data[8]; ///< buffer data for each plane/channel
77 
78  /**
79  * pointers to the data planes/channels.
80  *
81  * For video, this should simply point to data[].
82  *
83  * For planar audio, each channel has a separate data pointer, and
84  * linesize[0] contains the size of each channel buffer.
85  * For packed audio, there is just one data pointer, and linesize[0]
86  * contains the total size of the buffer for all channels.
87  *
88  * Note: Both data and extended_data will always be set, but for planar
89  * audio with more channels that can fit in data, extended_data must be used
90  * in order to access all channels.
91  */
92  uint8_t **extended_data;
93  int linesize[8]; ///< number of bytes per line
94 
95  /** private data to be used by a custom free function */
96  void *priv;
97  /**
98  * A pointer to the function to deallocate this buffer if the default
99  * function is not sufficient. This could, for example, add the memory
100  * back into a memory pool to be reused later without the overhead of
101  * reallocating it from scratch.
102  */
103  void (*free)(struct AVFilterBuffer *buf);
104 
105  int format; ///< media format
106  int w, h; ///< width and height of the allocated buffer
107  unsigned refcount; ///< number of references to this buffer
108 } AVFilterBuffer;
109 
110 #define AV_PERM_READ 0x01 ///< can read from the buffer
111 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
112 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
113 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
114 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
115 #define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
116 #define AV_PERM_ALIGN 0x40 ///< the buffer must be aligned
117 
118 #define AVFILTER_ALIGN 16 //not part of ABI
119 
120 /**
121  * Audio specific properties in a reference to an AVFilterBuffer. Since
122  * AVFilterBufferRef is common to different media formats, audio specific
123  * per reference properties must be separated out.
124  */
125 typedef struct AVFilterBufferRefAudioProps {
126  uint64_t channel_layout; ///< channel layout of audio buffer
127  int nb_samples; ///< number of audio samples per channel
128  int sample_rate; ///< audio buffer sample rate
129  int channels; ///< number of channels (do not access directly)
130 } AVFilterBufferRefAudioProps;
131 
132 /**
133  * Video specific properties in a reference to an AVFilterBuffer. Since
134  * AVFilterBufferRef is common to different media formats, video specific
135  * per reference properties must be separated out.
136  */
137 typedef struct AVFilterBufferRefVideoProps {
138  int w; ///< image width
139  int h; ///< image height
140  AVRational sample_aspect_ratio; ///< sample aspect ratio
141  int interlaced; ///< is frame interlaced
142  int top_field_first; ///< field order
143  enum AVPictureType pict_type; ///< picture type of the frame
144  int key_frame; ///< 1 -> keyframe, 0-> not
145  int qp_table_linesize; ///< qp_table stride
146  int qp_table_size; ///< qp_table size
147  int8_t *qp_table; ///< array of Quantization Parameters
148 } AVFilterBufferRefVideoProps;
149 
150 /**
151  * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
152  * a buffer to, for example, crop image without any memcpy, the buffer origin
153  * and dimensions are per-reference properties. Linesize is also useful for
154  * image flipping, frame to field filters, etc, and so is also per-reference.
155  *
156  * TODO: add anything necessary for frame reordering
157  */
158 typedef struct AVFilterBufferRef {
159  AVFilterBuffer *buf; ///< the buffer that this is a reference to
160  uint8_t *data[8]; ///< picture/audio data for each plane
161  /**
162  * pointers to the data planes/channels.
163  *
164  * For video, this should simply point to data[].
165  *
166  * For planar audio, each channel has a separate data pointer, and
167  * linesize[0] contains the size of each channel buffer.
168  * For packed audio, there is just one data pointer, and linesize[0]
169  * contains the total size of the buffer for all channels.
170  *
171  * Note: Both data and extended_data will always be set, but for planar
172  * audio with more channels that can fit in data, extended_data must be used
173  * in order to access all channels.
174  */
175  uint8_t **extended_data;
176  int linesize[8]; ///< number of bytes per line
177 
178  AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
179  AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
180 
181  /**
182  * presentation timestamp. The time unit may change during
183  * filtering, as it is specified in the link and the filter code
184  * may need to rescale the PTS accordingly.
185  */
186  int64_t pts;
187  int64_t pos; ///< byte position in stream, -1 if unknown
188 
189  int format; ///< media format
190 
191  int perms; ///< permissions, see the AV_PERM_* flags
192 
193  enum AVMediaType type; ///< media type of buffer data
194 
195  AVDictionary *metadata; ///< dictionary containing metadata key=value tags
196 } AVFilterBufferRef;
197 
198 /**
199  * Copy properties of src to dst, without copying the actual data
200  */
202 void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, const AVFilterBufferRef *src);
203 
204 /**
205  * Add a new reference to a buffer.
206  *
207  * @param ref an existing reference to the buffer
208  * @param pmask a bitmask containing the allowable permissions in the new
209  * reference
210  * @return a new reference to the buffer with the same properties as the
211  * old, excluding any permissions denied by pmask
212  */
214 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
215 
216 /**
217  * Remove a reference to a buffer. If this is the last reference to the
218  * buffer, the buffer itself is also automatically freed.
219  *
220  * @param ref reference to the buffer, may be NULL
221  *
222  * @note it is recommended to use avfilter_unref_bufferp() instead of this
223  * function
224  */
226 void avfilter_unref_buffer(AVFilterBufferRef *ref);
227 
228 /**
229  * Remove a reference to a buffer and set the pointer to NULL.
230  * If this is the last reference to the buffer, the buffer itself
231  * is also automatically freed.
232  *
233  * @param ref pointer to the buffer reference
234  */
236 void avfilter_unref_bufferp(AVFilterBufferRef **ref);
237 #endif
238 
239 /**
240  * Get the number of channels of a buffer reference.
241  */
243 int avfilter_ref_get_channels(AVFilterBufferRef *ref);
244 
245 #if FF_API_AVFILTERPAD_PUBLIC
246 /**
247  * A filter pad used for either input or output.
248  *
249  * See doc/filter_design.txt for details on how to implement the methods.
250  *
251  * @warning this struct might be removed from public API.
252  * users should call avfilter_pad_get_name() and avfilter_pad_get_type()
253  * to access the name and type fields; there should be no need to access
254  * any other fields from outside of libavfilter.
255  */
256 struct AVFilterPad {
257  /**
258  * Pad name. The name is unique among inputs and among outputs, but an
259  * input may have the same name as an output. This may be NULL if this
260  * pad has no need to ever be referenced by name.
261  */
262  const char *name;
263 
264  /**
265  * AVFilterPad type.
266  */
267  enum AVMediaType type;
268 
269  /**
270  * Input pads:
271  * Minimum required permissions on incoming buffers. Any buffer with
272  * insufficient permissions will be automatically copied by the filter
273  * system to a new buffer which provides the needed access permissions.
274  *
275  * Output pads:
276  * Guaranteed permissions on outgoing buffers. Any buffer pushed on the
277  * link must have at least these permissions; this fact is checked by
278  * asserts. It can be used to optimize buffer allocation.
279  */
280  attribute_deprecated int min_perms;
281 
282  /**
283  * Input pads:
284  * Permissions which are not accepted on incoming buffers. Any buffer
285  * which has any of these permissions set will be automatically copied
286  * by the filter system to a new buffer which does not have those
287  * permissions. This can be used to easily disallow buffers with
288  * AV_PERM_REUSE.
289  *
290  * Output pads:
291  * Permissions which are automatically removed on outgoing buffers. It
292  * can be used to optimize buffer allocation.
293  */
294  attribute_deprecated int rej_perms;
295 
296  /**
297  * @deprecated unused
298  */
299  int (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
300 
301  /**
302  * Callback function to get a video buffer. If NULL, the filter system will
303  * use ff_default_get_video_buffer().
304  *
305  * Input video pads only.
306  */
307  AVFrame *(*get_video_buffer)(AVFilterLink *link, int w, int h);
308 
309  /**
310  * Callback function to get an audio buffer. If NULL, the filter system will
311  * use ff_default_get_audio_buffer().
312  *
313  * Input audio pads only.
314  */
315  AVFrame *(*get_audio_buffer)(AVFilterLink *link, int nb_samples);
316 
317  /**
318  * @deprecated unused
319  */
320  int (*end_frame)(AVFilterLink *link);
321 
322  /**
323  * @deprecated unused
324  */
325  int (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
326 
327  /**
328  * Filtering callback. This is where a filter receives a frame with
329  * audio/video data and should do its processing.
330  *
331  * Input pads only.
332  *
333  * @return >= 0 on success, a negative AVERROR on error. This function
334  * must ensure that frame is properly unreferenced on error if it
335  * hasn't been passed on to another filter.
336  */
337  int (*filter_frame)(AVFilterLink *link, AVFrame *frame);
338 
339  /**
340  * Frame poll callback. This returns the number of immediately available
341  * samples. It should return a positive value if the next request_frame()
342  * is guaranteed to return one frame (with no delay).
343  *
344  * Defaults to just calling the source poll_frame() method.
345  *
346  * Output pads only.
347  */
348  int (*poll_frame)(AVFilterLink *link);
349 
350  /**
351  * Frame request callback. A call to this should result in at least one
352  * frame being output over the given link. This should return zero on
353  * success, and another value on error.
354  * See ff_request_frame() for the error codes with a specific
355  * meaning.
356  *
357  * Output pads only.
358  */
359  int (*request_frame)(AVFilterLink *link);
360 
361  /**
362  * Link configuration callback.
363  *
364  * For output pads, this should set the following link properties:
365  * video: width, height, sample_aspect_ratio, time_base
366  * audio: sample_rate.
367  *
368  * This should NOT set properties such as format, channel_layout, etc which
369  * are negotiated between filters by the filter system using the
370  * query_formats() callback before this function is called.
371  *
372  * For input pads, this should check the properties of the link, and update
373  * the filter's internal state as necessary.
374  *
375  * For both input and output pads, this should return zero on success,
376  * and another value on error.
377  */
378  int (*config_props)(AVFilterLink *link);
379 
380  /**
381  * The filter expects a fifo to be inserted on its input link,
382  * typically because it has a delay.
383  *
384  * input pads only.
385  */
386  int needs_fifo;
387 
388  /**
389  * The filter expects writable frames from its input link,
390  * duplicating data buffers if needed.
391  *
392  * input pads only.
393  */
394  int needs_writable;
395 };
396 #endif
397 
398 /**
399  * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
400  * AVFilter.inputs/outputs).
401  */
402 int avfilter_pad_count(const AVFilterPad *pads);
403 
404 /**
405  * Get the name of an AVFilterPad.
406  *
407  * @param pads an array of AVFilterPads
408  * @param pad_idx index of the pad in the array it; is the caller's
409  * responsibility to ensure the index is valid
410  *
411  * @return name of the pad_idx'th pad in pads
412  */
413 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
414 
415 /**
416  * Get the type of an AVFilterPad.
417  *
418  * @param pads an array of AVFilterPads
419  * @param pad_idx index of the pad in the array; it is the caller's
420  * responsibility to ensure the index is valid
421  *
422  * @return type of the pad_idx'th pad in pads
423  */
424 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
425 
426 /**
427  * The number of the filter inputs is not determined just by AVFilter.inputs.
428  * The filter might add additional inputs during initialization depending on the
429  * options supplied to it.
430  */
431 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
432 /**
433  * The number of the filter outputs is not determined just by AVFilter.outputs.
434  * The filter might add additional outputs during initialization depending on
435  * the options supplied to it.
436  */
437 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
438 /**
439  * The filter supports multithreading by splitting frames into multiple parts
440  * and processing them concurrently.
441  */
442 #define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
443 /**
444  * Some filters support a generic "enable" expression option that can be used
445  * to enable or disable a filter in the timeline. Filters supporting this
446  * option have this flag set. When the enable expression is false, the default
447  * no-op filter_frame() function is called in place of the filter_frame()
448  * callback defined on each input pad, thus the frame is passed unchanged to
449  * the next filters.
450  */
451 #define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC (1 << 16)
452 /**
453  * Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will
454  * have its filter_frame() callback(s) called as usual even when the enable
455  * expression is false. The filter will disable filtering within the
456  * filter_frame() callback(s) itself, for example executing code depending on
457  * the AVFilterContext->is_disabled value.
458  */
459 #define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL (1 << 17)
460 /**
461  * Handy mask to test whether the filter supports or no the timeline feature
462  * (internally or generically).
463  */
464 #define AVFILTER_FLAG_SUPPORT_TIMELINE (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
465 
466 /**
467  * Filter definition. This defines the pads a filter contains, and all the
468  * callback functions used to interact with the filter.
469  */
470 typedef struct AVFilter {
471  /**
472  * Filter name. Must be non-NULL and unique among filters.
473  */
474  const char *name;
475 
476  /**
477  * A description of the filter. May be NULL.
478  *
479  * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
480  */
481  const char *description;
482 
483  /**
484  * List of inputs, terminated by a zeroed element.
485  *
486  * NULL if there are no (static) inputs. Instances of filters with
487  * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
488  * this list.
489  */
491  /**
492  * List of outputs, terminated by a zeroed element.
493  *
494  * NULL if there are no (static) outputs. Instances of filters with
495  * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
496  * this list.
497  */
499 
500  /**
501  * A class for the private data, used to declare filter private AVOptions.
502  * This field is NULL for filters that do not declare any options.
503  *
504  * If this field is non-NULL, the first member of the filter private data
505  * must be a pointer to AVClass, which will be set by libavfilter generic
506  * code to this class.
507  */
509 
510  /**
511  * A combination of AVFILTER_FLAG_*
512  */
513  int flags;
514 
515  /*****************************************************************
516  * All fields below this line are not part of the public API. They
517  * may not be used outside of libavfilter and can be changed and
518  * removed at will.
519  * New public fields should be added right above.
520  *****************************************************************
521  */
522 
523  /**
524  * Filter initialization function.
525  *
526  * This callback will be called only once during the filter lifetime, after
527  * all the options have been set, but before links between filters are
528  * established and format negotiation is done.
529  *
530  * Basic filter initialization should be done here. Filters with dynamic
531  * inputs and/or outputs should create those inputs/outputs here based on
532  * provided options. No more changes to this filter's inputs/outputs can be
533  * done after this callback.
534  *
535  * This callback must not assume that the filter links exist or frame
536  * parameters are known.
537  *
538  * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
539  * initialization fails, so this callback does not have to clean up on
540  * failure.
541  *
542  * @return 0 on success, a negative AVERROR on failure
543  */
544  int (*init)(AVFilterContext *ctx);
545 
546  /**
547  * Should be set instead of @ref AVFilter.init "init" by the filters that
548  * want to pass a dictionary of AVOptions to nested contexts that are
549  * allocated during init.
550  *
551  * On return, the options dict should be freed and replaced with one that
552  * contains all the options which could not be processed by this filter (or
553  * with NULL if all the options were processed).
554  *
555  * Otherwise the semantics is the same as for @ref AVFilter.init "init".
556  */
558 
559  /**
560  * Filter uninitialization function.
561  *
562  * Called only once right before the filter is freed. Should deallocate any
563  * memory held by the filter, release any buffer references, etc. It does
564  * not need to deallocate the AVFilterContext.priv memory itself.
565  *
566  * This callback may be called even if @ref AVFilter.init "init" was not
567  * called or failed, so it must be prepared to handle such a situation.
568  */
570 
571  /**
572  * Query formats supported by the filter on its inputs and outputs.
573  *
574  * This callback is called after the filter is initialized (so the inputs
575  * and outputs are fixed), shortly before the format negotiation. This
576  * callback may be called more than once.
577  *
578  * This callback must set AVFilterLink.out_formats on every input link and
579  * AVFilterLink.in_formats on every output link to a list of pixel/sample
580  * formats that the filter supports on that link. For audio links, this
581  * filter must also set @ref AVFilterLink.in_samplerates "in_samplerates" /
582  * @ref AVFilterLink.out_samplerates "out_samplerates" and
583  * @ref AVFilterLink.in_channel_layouts "in_channel_layouts" /
584  * @ref AVFilterLink.out_channel_layouts "out_channel_layouts" analogously.
585  *
586  * This callback may be NULL for filters with one input, in which case
587  * libavfilter assumes that it supports all input formats and preserves
588  * them on output.
589  *
590  * @return zero on success, a negative value corresponding to an
591  * AVERROR code otherwise
592  */
594 
595  int priv_size; ///< size of private data to allocate for the filter
596 
597  /**
598  * Used by the filter registration system. Must not be touched by any other
599  * code.
600  */
601  struct AVFilter *next;
602 
603  /**
604  * Make the filter instance process a command.
605  *
606  * @param cmd the command to process, for handling simplicity all commands must be alphanumeric only
607  * @param arg the argument for the command
608  * @param res a buffer with size res_size where the filter(s) can return a response. This must not change when the command is not supported.
609  * @param flags if AVFILTER_CMD_FLAG_FAST is set and the command would be
610  * time consuming then a filter should treat it like an unsupported command
611  *
612  * @returns >=0 on success otherwise an error code.
613  * AVERROR(ENOSYS) on unsupported commands
614  */
615  int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);
616 
617  /**
618  * Filter initialization function, alternative to the init()
619  * callback. Args contains the user-supplied parameters, opaque is
620  * used for providing binary data.
621  */
622  int (*init_opaque)(AVFilterContext *ctx, void *opaque);
623 } AVFilter;
624 
625 /**
626  * Process multiple parts of the frame concurrently.
627  */
628 #define AVFILTER_THREAD_SLICE (1 << 0)
629 
630 typedef struct AVFilterInternal AVFilterInternal;
631 
632 /** An instance of a filter */
634  const AVClass *av_class; ///< needed for av_log() and filters common options
635 
636  const AVFilter *filter; ///< the AVFilter of which this is an instance
637 
638  char *name; ///< name of this filter instance
639 
640  AVFilterPad *input_pads; ///< array of input pads
641  AVFilterLink **inputs; ///< array of pointers to input links
642 #if FF_API_FOO_COUNT
643  attribute_deprecated unsigned input_count; ///< @deprecated use nb_inputs
644 #endif
645  unsigned nb_inputs; ///< number of input pads
646 
647  AVFilterPad *output_pads; ///< array of output pads
648  AVFilterLink **outputs; ///< array of pointers to output links
649 #if FF_API_FOO_COUNT
650  attribute_deprecated unsigned output_count; ///< @deprecated use nb_outputs
651 #endif
652  unsigned nb_outputs; ///< number of output pads
653 
654  void *priv; ///< private data for use by the filter
655 
656  struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
657 
658  /**
659  * Type of multithreading being allowed/used. A combination of
660  * AVFILTER_THREAD_* flags.
661  *
662  * May be set by the caller before initializing the filter to forbid some
663  * or all kinds of multithreading for this filter. The default is allowing
664  * everything.
665  *
666  * When the filter is initialized, this field is combined using bit AND with
667  * AVFilterGraph.thread_type to get the final mask used for determining
668  * allowed threading types. I.e. a threading type needs to be set in both
669  * to be allowed.
670  *
671  * After the filter is initialized, libavfilter sets this field to the
672  * threading type that is actually used (0 for no multithreading).
673  */
675 
676  /**
677  * An opaque struct for libavfilter internal use.
678  */
679  AVFilterInternal *internal;
680 
682 
683  char *enable_str; ///< enable expression string
684  void *enable; ///< parsed expression (AVExpr*)
685  double *var_values; ///< variable values for the enable expression
686  int is_disabled; ///< the enabled state from the last expression evaluation
687 };
688 
689 /**
690  * A link between two filters. This contains pointers to the source and
691  * destination filters between which this link exists, and the indexes of
692  * the pads involved. In addition, this link also contains the parameters
693  * which have been negotiated and agreed upon between the filter, such as
694  * image dimensions, format, etc.
695  */
696 struct AVFilterLink {
697  AVFilterContext *src; ///< source filter
698  AVFilterPad *srcpad; ///< output pad on the source filter
699 
700  AVFilterContext *dst; ///< dest filter
701  AVFilterPad *dstpad; ///< input pad on the dest filter
702 
703  enum AVMediaType type; ///< filter media type
704 
705  /* These parameters apply only to video */
706  int w; ///< agreed upon image width
707  int h; ///< agreed upon image height
708  AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
709  /* These parameters apply only to audio */
710  uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
711  int sample_rate; ///< samples per second
712 
713  int format; ///< agreed upon media format
714 
715  /**
716  * Define the time base used by the PTS of the frames/samples
717  * which will pass through this link.
718  * During the configuration stage, each filter is supposed to
719  * change only the output timebase, while the timebase of the
720  * input link is assumed to be an unchangeable property.
721  */
723 
724  /*****************************************************************
725  * All fields below this line are not part of the public API. They
726  * may not be used outside of libavfilter and can be changed and
727  * removed at will.
728  * New public fields should be added right above.
729  *****************************************************************
730  */
731  /**
732  * Lists of formats and channel layouts supported by the input and output
733  * filters respectively. These lists are used for negotiating the format
734  * to actually be used, which will be loaded into the format and
735  * channel_layout members, above, when chosen.
736  *
737  */
740 
741  /**
742  * Lists of channel layouts and sample rates used for automatic
743  * negotiation.
744  */
749 
750  /**
751  * Audio only, the destination filter sets this to a non-zero value to
752  * request that buffers with the given number of samples should be sent to
753  * it. AVFilterPad.needs_fifo must also be set on the corresponding input
754  * pad.
755  * Last buffer before EOF will be padded with silence.
756  */
758 
759  /** stage of the initialization of the link properties (dimensions, etc) */
760  enum {
761  AVLINK_UNINIT = 0, ///< not started
762  AVLINK_STARTINIT, ///< started, but incomplete
763  AVLINK_INIT ///< complete
764  } init_state;
765 
767 
768  /**
769  * Graph the filter belongs to.
770  */
772 
773  /**
774  * Current timestamp of the link, as defined by the most recent
775  * frame(s), in AV_TIME_BASE units.
776  */
777  int64_t current_pts;
778 
779  /**
780  * Index in the age array.
781  */
783 
784  /**
785  * Frame rate of the stream on the link, or 1/0 if unknown;
786  * if left to 0/0, will be automatically be copied from the first input
787  * of the source filter if it exists.
788  *
789  * Sources should set it to the best estimation of the real frame rate.
790  * Filters should update it if necessary depending on their function.
791  * Sinks can use it to set a default output frame rate.
792  * It is similar to the r_frame_rate field in AVStream.
793  */
795 
796  /**
797  * Buffer partially filled with samples to achieve a fixed/minimum size.
798  */
800 
801  /**
802  * Size of the partial buffer to allocate.
803  * Must be between min_samples and max_samples.
804  */
806 
807  /**
808  * Minimum number of samples to filter at once. If filter_frame() is
809  * called with fewer samples, it will accumulate them in partial_buf.
810  * This field and the related ones must not be changed after filtering
811  * has started.
812  * If 0, all related fields are ignored.
813  */
815 
816  /**
817  * Maximum number of samples to filter at once. If filter_frame() is
818  * called with more samples, it will split them.
819  */
821 
822  /**
823  * The buffer reference currently being received across the link by the
824  * destination filter. This is used internally by the filter system to
825  * allow automatic copying of buffers which do not have sufficient
826  * permissions for the destination. This should not be accessed directly
827  * by the filters.
828  */
829  AVFilterBufferRef *cur_buf_copy;
830 
831  /**
832  * True if the link is closed.
833  * If set, all attempts of start_frame, filter_frame or request_frame
834  * will fail with AVERROR_EOF, and if necessary the reference will be
835  * destroyed.
836  * If request_frame returns AVERROR_EOF, this flag is set on the
837  * corresponding link.
838  * It can be set also be set by either the source or the destination
839  * filter.
840  */
841  int closed;
842 
843  /**
844  * Number of channels.
845  */
846  int channels;
847 
848  /**
849  * True if a frame is being requested on the link.
850  * Used internally by the framework.
851  */
852  unsigned frame_requested;
853 
854  /**
855  * Link processing flags.
856  */
857  unsigned flags;
858 
859  /**
860  * Number of past frames sent through the link.
861  */
862  int64_t frame_count;
863 };
864 
865 /**
866  * Link two filters together.
867  *
868  * @param src the source filter
869  * @param srcpad index of the output pad on the source filter
870  * @param dst the destination filter
871  * @param dstpad index of the input pad on the destination filter
872  * @return zero on success
873  */
874 int avfilter_link(AVFilterContext *src, unsigned srcpad,
875  AVFilterContext *dst, unsigned dstpad);
876 
877 /**
878  * Free the link in *link, and set its pointer to NULL.
879  */
880 void avfilter_link_free(AVFilterLink **link);
881 
882 /**
883  * Get the number of channels of a link.
884  */
886 
887 /**
888  * Set the closed field of a link.
889  */
890 void avfilter_link_set_closed(AVFilterLink *link, int closed);
891 
892 /**
893  * Negotiate the media format, dimensions, etc of all inputs to a filter.
894  *
895  * @param filter the filter to negotiate the properties for its inputs
896  * @return zero on successful negotiation
897  */
899 
900 #if FF_API_AVFILTERBUFFER
901 /**
902  * Create a buffer reference wrapped around an already allocated image
903  * buffer.
904  *
905  * @param data pointers to the planes of the image to reference
906  * @param linesize linesizes for the planes of the image to reference
907  * @param perms the required access permissions
908  * @param w the width of the image specified by the data and linesize arrays
909  * @param h the height of the image specified by the data and linesize arrays
910  * @param format the pixel format of the image specified by the data and linesize arrays
911  */
913 AVFilterBufferRef *
914 avfilter_get_video_buffer_ref_from_arrays(uint8_t * const data[4], const int linesize[4], int perms,
915  int w, int h, enum AVPixelFormat format);
916 
917 /**
918  * Create an audio buffer reference wrapped around an already
919  * allocated samples buffer.
920  *
921  * See avfilter_get_audio_buffer_ref_from_arrays_channels() for a version
922  * that can handle unknown channel layouts.
923  *
924  * @param data pointers to the samples plane buffers
925  * @param linesize linesize for the samples plane buffers
926  * @param perms the required access permissions
927  * @param nb_samples number of samples per channel
928  * @param sample_fmt the format of each sample in the buffer to allocate
929  * @param channel_layout the channel layout of the buffer
930  */
932 AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
933  int linesize,
934  int perms,
935  int nb_samples,
936  enum AVSampleFormat sample_fmt,
937  uint64_t channel_layout);
938 /**
939  * Create an audio buffer reference wrapped around an already
940  * allocated samples buffer.
941  *
942  * @param data pointers to the samples plane buffers
943  * @param linesize linesize for the samples plane buffers
944  * @param perms the required access permissions
945  * @param nb_samples number of samples per channel
946  * @param sample_fmt the format of each sample in the buffer to allocate
947  * @param channels the number of channels of the buffer
948  * @param channel_layout the channel layout of the buffer,
949  * must be either 0 or consistent with channels
950  */
952 AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays_channels(uint8_t **data,
953  int linesize,
954  int perms,
955  int nb_samples,
956  enum AVSampleFormat sample_fmt,
957  int channels,
958  uint64_t channel_layout);
959 
960 #endif
961 
962 
963 #define AVFILTER_CMD_FLAG_ONE 1 ///< Stop once a filter understood the command (for target=all for example), fast filters are favored automatically
964 #define AVFILTER_CMD_FLAG_FAST 2 ///< Only execute command when its fast (like a video out that supports contrast adjustment in hw)
965 
966 /**
967  * Make the filter instance process a command.
968  * It is recommended to use avfilter_graph_send_command().
969  */
970 int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
971 
972 /** Initialize the filter system. Register all builtin filters. */
973 void avfilter_register_all(void);
974 
975 #if FF_API_OLD_FILTER_REGISTER
976 /** Uninitialize the filter system. Unregister all filters. */
978 void avfilter_uninit(void);
979 #endif
980 
981 /**
982  * Register a filter. This is only needed if you plan to use
983  * avfilter_get_by_name later to lookup the AVFilter structure by name. A
984  * filter can still by instantiated with avfilter_graph_alloc_filter even if it
985  * is not registered.
986  *
987  * @param filter the filter to register
988  * @return 0 if the registration was successful, a negative value
989  * otherwise
990  */
992 
993 /**
994  * Get a filter definition matching the given name.
995  *
996  * @param name the filter name to find
997  * @return the filter definition, if any matching one is registered.
998  * NULL if none found.
999  */
1000 #if !FF_API_NOCONST_GET_NAME
1001 const
1002 #endif
1003 AVFilter *avfilter_get_by_name(const char *name);
1004 
1005 /**
1006  * Iterate over all registered filters.
1007  * @return If prev is non-NULL, next registered filter after prev or NULL if
1008  * prev is the last filter. If prev is NULL, return the first registered filter.
1009  */
1010 const AVFilter *avfilter_next(const AVFilter *prev);
1011 
1012 #if FF_API_OLD_FILTER_REGISTER
1013 /**
1014  * If filter is NULL, returns a pointer to the first registered filter pointer,
1015  * if filter is non-NULL, returns the next pointer after filter.
1016  * If the returned pointer points to NULL, the last registered filter
1017  * was already reached.
1018  * @deprecated use avfilter_next()
1019  */
1021 AVFilter **av_filter_next(AVFilter **filter);
1022 #endif
1023 
1024 #if FF_API_AVFILTER_OPEN
1025 /**
1026  * Create a filter instance.
1027  *
1028  * @param filter_ctx put here a pointer to the created filter context
1029  * on success, NULL on failure
1030  * @param filter the filter to create an instance of
1031  * @param inst_name Name to give to the new instance. Can be NULL for none.
1032  * @return >= 0 in case of success, a negative error code otherwise
1033  * @deprecated use avfilter_graph_alloc_filter() instead
1034  */
1036 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
1037 #endif
1038 
1039 
1040 #if FF_API_AVFILTER_INIT_FILTER
1041 /**
1042  * Initialize a filter.
1043  *
1044  * @param filter the filter to initialize
1045  * @param args A string of parameters to use when initializing the filter.
1046  * The format and meaning of this string varies by filter.
1047  * @param opaque Any extra non-string data needed by the filter. The meaning
1048  * of this parameter varies by filter.
1049  * @return zero on success
1050  */
1052 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
1053 #endif
1054 
1055 /**
1056  * Initialize a filter with the supplied parameters.
1057  *
1058  * @param ctx uninitialized filter context to initialize
1059  * @param args Options to initialize the filter with. This must be a
1060  * ':'-separated list of options in the 'key=value' form.
1061  * May be NULL if the options have been set directly using the
1062  * AVOptions API or there are no options that need to be set.
1063  * @return 0 on success, a negative AVERROR on failure
1064  */
1065 int avfilter_init_str(AVFilterContext *ctx, const char *args);
1066 
1067 /**
1068  * Initialize a filter with the supplied dictionary of options.
1069  *
1070  * @param ctx uninitialized filter context to initialize
1071  * @param options An AVDictionary filled with options for this filter. On
1072  * return this parameter will be destroyed and replaced with
1073  * a dict containing options that were not found. This dictionary
1074  * must be freed by the caller.
1075  * May be NULL, then this function is equivalent to
1076  * avfilter_init_str() with the second parameter set to NULL.
1077  * @return 0 on success, a negative AVERROR on failure
1078  *
1079  * @note This function and avfilter_init_str() do essentially the same thing,
1080  * the difference is in manner in which the options are passed. It is up to the
1081  * calling code to choose whichever is more preferable. The two functions also
1082  * behave differently when some of the provided options are not declared as
1083  * supported by the filter. In such a case, avfilter_init_str() will fail, but
1084  * this function will leave those extra options in the options AVDictionary and
1085  * continue as usual.
1086  */
1088 
1089 /**
1090  * Free a filter context. This will also remove the filter from its
1091  * filtergraph's list of filters.
1092  *
1093  * @param filter the filter to free
1094  */
1096 
1097 /**
1098  * Insert a filter in the middle of an existing link.
1099  *
1100  * @param link the link into which the filter should be inserted
1101  * @param filt the filter to be inserted
1102  * @param filt_srcpad_idx the input pad on the filter to connect
1103  * @param filt_dstpad_idx the output pad on the filter to connect
1104  * @return zero on success
1105  */
1107  unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
1108 
1109 #if FF_API_AVFILTERBUFFER
1110 /**
1111  * Copy the frame properties of src to dst, without copying the actual
1112  * image data.
1113  *
1114  * @return 0 on success, a negative number on error.
1115  */
1117 int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
1118 
1119 /**
1120  * Copy the frame properties and data pointers of src to dst, without copying
1121  * the actual data.
1122  *
1123  * @return 0 on success, a negative number on error.
1124  */
1126 int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src);
1127 #endif
1128 
1129 /**
1130  * @return AVClass for AVFilterContext.
1131  *
1132  * @see av_opt_find().
1133  */
1134 const AVClass *avfilter_get_class(void);
1135 
1137 
1138 /**
1139  * A function pointer passed to the @ref AVFilterGraph.execute callback to be
1140  * executed multiple times, possibly in parallel.
1141  *
1142  * @param ctx the filter context the job belongs to
1143  * @param arg an opaque parameter passed through from @ref
1144  * AVFilterGraph.execute
1145  * @param jobnr the index of the job being executed
1146  * @param nb_jobs the total number of jobs
1147  *
1148  * @return 0 on success, a negative AVERROR on error
1149  */
1150 typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
1151 
1152 /**
1153  * A function executing multiple jobs, possibly in parallel.
1154  *
1155  * @param ctx the filter context to which the jobs belong
1156  * @param func the function to be called multiple times
1157  * @param arg the argument to be passed to func
1158  * @param ret a nb_jobs-sized array to be filled with return values from each
1159  * invocation of func
1160  * @param nb_jobs the number of jobs to execute
1161  *
1162  * @return 0 on success, a negative AVERROR on error
1163  */
1165  void *arg, int *ret, int nb_jobs);
1166 
1167 typedef struct AVFilterGraph {
1169 #if FF_API_FOO_COUNT
1171  unsigned filter_count_unused;
1172 #endif
1174 #if !FF_API_FOO_COUNT
1175  unsigned nb_filters;
1176 #endif
1177 
1178  char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
1179  char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
1180 #if FF_API_FOO_COUNT
1181  unsigned nb_filters;
1182 #endif
1183 
1184  /**
1185  * Type of multithreading allowed for filters in this graph. A combination
1186  * of AVFILTER_THREAD_* flags.
1187  *
1188  * May be set by the caller at any point, the setting will apply to all
1189  * filters initialized after that. The default is allowing everything.
1190  *
1191  * When a filter in this graph is initialized, this field is combined using
1192  * bit AND with AVFilterContext.thread_type to get the final mask used for
1193  * determining allowed threading types. I.e. a threading type needs to be
1194  * set in both to be allowed.
1195  */
1197 
1198  /**
1199  * Maximum number of threads used by filters in this graph. May be set by
1200  * the caller before adding any filters to the filtergraph. Zero (the
1201  * default) means that the number of threads is determined automatically.
1202  */
1204 
1205  /**
1206  * Opaque object for libavfilter internal use.
1207  */
1209 
1210  /**
1211  * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
1212  * be used from callbacks like @ref AVFilterGraph.execute.
1213  * Libavfilter will not touch this field in any way.
1214  */
1215  void *opaque;
1216 
1217  /**
1218  * This callback may be set by the caller immediately after allocating the
1219  * graph and before adding any filters to it, to provide a custom
1220  * multithreading implementation.
1221  *
1222  * If set, filters with slice threading capability will call this callback
1223  * to execute multiple jobs in parallel.
1224  *
1225  * If this field is left unset, libavfilter will use its internal
1226  * implementation, which may or may not be multithreaded depending on the
1227  * platform and build options.
1228  */
1230 
1231  char *aresample_swr_opts; ///< swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
1232 
1233  /**
1234  * Private fields
1235  *
1236  * The following fields are for internal use only.
1237  * Their type, offset, number and semantic can change without notice.
1238  */
1239 
1242 
1244 } AVFilterGraph;
1245 
1246 /**
1247  * Allocate a filter graph.
1248  */
1250 
1251 /**
1252  * Create a new filter instance in a filter graph.
1253  *
1254  * @param graph graph in which the new filter will be used
1255  * @param filter the filter to create an instance of
1256  * @param name Name to give to the new instance (will be copied to
1257  * AVFilterContext.name). This may be used by the caller to identify
1258  * different filters, libavfilter itself assigns no semantics to
1259  * this parameter. May be NULL.
1260  *
1261  * @return the context of the newly created filter instance (note that it is
1262  * also retrievable directly through AVFilterGraph.filters or with
1263  * avfilter_graph_get_filter()) on success or NULL on failure.
1264  */
1266  const AVFilter *filter,
1267  const char *name);
1268 
1269 /**
1270  * Get a filter instance identified by instance name from graph.
1271  *
1272  * @param graph filter graph to search through.
1273  * @param name filter instance name (should be unique in the graph).
1274  * @return the pointer to the found filter instance or NULL if it
1275  * cannot be found.
1276  */
1278 
1279 #if FF_API_AVFILTER_OPEN
1280 /**
1281  * Add an existing filter instance to a filter graph.
1282  *
1283  * @param graphctx the filter graph
1284  * @param filter the filter to be added
1285  *
1286  * @deprecated use avfilter_graph_alloc_filter() to allocate a filter in a
1287  * filter graph
1288  */
1290 int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
1291 #endif
1292 
1293 /**
1294  * Create and add a filter instance into an existing graph.
1295  * The filter instance is created from the filter filt and inited
1296  * with the parameters args and opaque.
1297  *
1298  * In case of success put in *filt_ctx the pointer to the created
1299  * filter instance, otherwise set *filt_ctx to NULL.
1300  *
1301  * @param name the instance name to give to the created filter instance
1302  * @param graph_ctx the filter graph
1303  * @return a negative AVERROR error code in case of failure, a non
1304  * negative value otherwise
1305  */
1307  const char *name, const char *args, void *opaque,
1308  AVFilterGraph *graph_ctx);
1309 
1310 /**
1311  * Enable or disable automatic format conversion inside the graph.
1312  *
1313  * Note that format conversion can still happen inside explicitly inserted
1314  * scale and aresample filters.
1315  *
1316  * @param flags any of the AVFILTER_AUTO_CONVERT_* constants
1317  */
1318 void avfilter_graph_set_auto_convert(AVFilterGraph *graph, unsigned flags);
1319 
1320 enum {
1321  AVFILTER_AUTO_CONVERT_ALL = 0, /**< all automatic conversions enabled */
1322  AVFILTER_AUTO_CONVERT_NONE = -1, /**< all automatic conversions disabled */
1323 };
1324 
1325 /**
1326  * Check validity and configure all the links and formats in the graph.
1327  *
1328  * @param graphctx the filter graph
1329  * @param log_ctx context used for logging
1330  * @return >= 0 in case of success, a negative AVERROR code otherwise
1331  */
1332 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
1333 
1334 /**
1335  * Free a graph, destroy its links, and set *graph to NULL.
1336  * If *graph is NULL, do nothing.
1337  */
1338 void avfilter_graph_free(AVFilterGraph **graph);
1339 
1340 /**
1341  * A linked-list of the inputs/outputs of the filter chain.
1342  *
1343  * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
1344  * where it is used to communicate open (unlinked) inputs and outputs from and
1345  * to the caller.
1346  * This struct specifies, per each not connected pad contained in the graph, the
1347  * filter context and the pad index required for establishing a link.
1348  */
1349 typedef struct AVFilterInOut {
1350  /** unique name for this input/output in the list */
1351  char *name;
1352 
1353  /** filter context associated to this input/output */
1355 
1356  /** index of the filt_ctx pad to use for linking */
1357  int pad_idx;
1358 
1359  /** next input/input in the list, NULL if this is the last */
1361 } AVFilterInOut;
1362 
1363 /**
1364  * Allocate a single AVFilterInOut entry.
1365  * Must be freed with avfilter_inout_free().
1366  * @return allocated AVFilterInOut on success, NULL on failure.
1367  */
1369 
1370 /**
1371  * Free the supplied list of AVFilterInOut and set *inout to NULL.
1372  * If *inout is NULL, do nothing.
1373  */
1374 void avfilter_inout_free(AVFilterInOut **inout);
1375 
1376 #if AV_HAVE_INCOMPATIBLE_LIBAV_ABI || !FF_API_OLD_GRAPH_PARSE
1377 /**
1378  * Add a graph described by a string to a graph.
1379  *
1380  * @note The caller must provide the lists of inputs and outputs,
1381  * which therefore must be known before calling the function.
1382  *
1383  * @note The inputs parameter describes inputs of the already existing
1384  * part of the graph; i.e. from the point of view of the newly created
1385  * part, they are outputs. Similarly the outputs parameter describes
1386  * outputs of the already existing filters, which are provided as
1387  * inputs to the parsed filters.
1388  *
1389  * @param graph the filter graph where to link the parsed graph context
1390  * @param filters string to be parsed
1391  * @param inputs linked list to the inputs of the graph
1392  * @param outputs linked list to the outputs of the graph
1393  * @return zero on success, a negative AVERROR code on error
1394  */
1395 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
1397  void *log_ctx);
1398 #else
1399 /**
1400  * Add a graph described by a string to a graph.
1401  *
1402  * @param graph the filter graph where to link the parsed graph context
1403  * @param filters string to be parsed
1404  * @param inputs pointer to a linked list to the inputs of the graph, may be NULL.
1405  * If non-NULL, *inputs is updated to contain the list of open inputs
1406  * after the parsing, should be freed with avfilter_inout_free().
1407  * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
1408  * If non-NULL, *outputs is updated to contain the list of open outputs
1409  * after the parsing, should be freed with avfilter_inout_free().
1410  * @return non negative on success, a negative AVERROR code on error
1411  * @deprecated Use avfilter_graph_parse_ptr() instead.
1412  */
1414 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
1416  void *log_ctx);
1417 #endif
1418 
1419 /**
1420  * Add a graph described by a string to a graph.
1421  *
1422  * @param graph the filter graph where to link the parsed graph context
1423  * @param filters string to be parsed
1424  * @param inputs pointer to a linked list to the inputs of the graph, may be NULL.
1425  * If non-NULL, *inputs is updated to contain the list of open inputs
1426  * after the parsing, should be freed with avfilter_inout_free().
1427  * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
1428  * If non-NULL, *outputs is updated to contain the list of open outputs
1429  * after the parsing, should be freed with avfilter_inout_free().
1430  * @return non negative on success, a negative AVERROR code on error
1431  */
1432 int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
1434  void *log_ctx);
1435 
1436 /**
1437  * Add a graph described by a string to a graph.
1438  *
1439  * @param[in] graph the filter graph where to link the parsed graph context
1440  * @param[in] filters string to be parsed
1441  * @param[out] inputs a linked list of all free (unlinked) inputs of the
1442  * parsed graph will be returned here. It is to be freed
1443  * by the caller using avfilter_inout_free().
1444  * @param[out] outputs a linked list of all free (unlinked) outputs of the
1445  * parsed graph will be returned here. It is to be freed by the
1446  * caller using avfilter_inout_free().
1447  * @return zero on success, a negative AVERROR code on error
1448  *
1449  * @note This function returns the inputs and outputs that are left
1450  * unlinked after parsing the graph and the caller then deals with
1451  * them.
1452  * @note This function makes no reference whatsoever to already
1453  * existing parts of the graph and the inputs parameter will on return
1454  * contain inputs of the newly parsed part of the graph. Analogously
1455  * the outputs parameter will contain outputs of the newly created
1456  * filters.
1457  */
1458 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
1461 
1462 /**
1463  * Send a command to one or more filter instances.
1464  *
1465  * @param graph the filter graph
1466  * @param target the filter(s) to which the command should be sent
1467  * "all" sends to all filters
1468  * otherwise it can be a filter or filter instance name
1469  * which will send the command to all matching filters.
1470  * @param cmd the command to send, for handling simplicity all commands must be alphanumeric only
1471  * @param arg the argument for the command
1472  * @param res a buffer with size res_size where the filter(s) can return a response.
1473  *
1474  * @returns >=0 on success otherwise an error code.
1475  * AVERROR(ENOSYS) on unsupported commands
1476  */
1477 int avfilter_graph_send_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, char *res, int res_len, int flags);
1478 
1479 /**
1480  * Queue a command for one or more filter instances.
1481  *
1482  * @param graph the filter graph
1483  * @param target the filter(s) to which the command should be sent
1484  * "all" sends to all filters
1485  * otherwise it can be a filter or filter instance name
1486  * which will send the command to all matching filters.
1487  * @param cmd the command to sent, for handling simplicity all commands must be alphanumeric only
1488  * @param arg the argument for the command
1489  * @param ts time at which the command should be sent to the filter
1490  *
1491  * @note As this executes commands after this function returns, no return code
1492  * from the filter is provided, also AVFILTER_CMD_FLAG_ONE is not supported.
1493  */
1494 int avfilter_graph_queue_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, int flags, double ts);
1495 
1496 
1497 /**
1498  * Dump a graph into a human-readable string representation.
1499  *
1500  * @param graph the graph to dump
1501  * @param options formatting options; currently ignored
1502  * @return a string, or NULL in case of memory allocation failure;
1503  * the string must be freed using av_free
1504  */
1505 char *avfilter_graph_dump(AVFilterGraph *graph, const char *options);
1506 
1507 /**
1508  * Request a frame on the oldest sink link.
1509  *
1510  * If the request returns AVERROR_EOF, try the next.
1511  *
1512  * Note that this function is not meant to be the sole scheduling mechanism
1513  * of a filtergraph, only a convenience function to help drain a filtergraph
1514  * in a balanced way under normal circumstances.
1515  *
1516  * Also note that AVERROR_EOF does not mean that frames did not arrive on
1517  * some of the sinks during the process.
1518  * When there are multiple sink links, in case the requested link
1519  * returns an EOF, this may cause a filter to flush pending frames
1520  * which are sent to another sink link, although unrequested.
1521  *
1522  * @return the return value of ff_request_frame(),
1523  * or AVERROR_EOF if all links returned AVERROR_EOF
1524  */
1526 
1527 /**
1528  * @}
1529  */
1530 
1531 #endif /* AVFILTER_AVFILTER_H */