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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, 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  int needs_writable;
389 };
390 #endif
391 
392 /**
393  * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
394  * AVFilter.inputs/outputs).
395  */
396 int avfilter_pad_count(const AVFilterPad *pads);
397 
398 /**
399  * Get the name of an AVFilterPad.
400  *
401  * @param pads an array of AVFilterPads
402  * @param pad_idx index of the pad in the array it; is the caller's
403  * responsibility to ensure the index is valid
404  *
405  * @return name of the pad_idx'th pad in pads
406  */
407 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
408 
409 /**
410  * Get the type of an AVFilterPad.
411  *
412  * @param pads an array of AVFilterPads
413  * @param pad_idx index of the pad in the array; it is the caller's
414  * responsibility to ensure the index is valid
415  *
416  * @return type of the pad_idx'th pad in pads
417  */
418 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
419 
420 /**
421  * The number of the filter inputs is not determined just by AVFilter.inputs.
422  * The filter might add additional inputs during initialization depending on the
423  * options supplied to it.
424  */
425 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
426 /**
427  * The number of the filter outputs is not determined just by AVFilter.outputs.
428  * The filter might add additional outputs during initialization depending on
429  * the options supplied to it.
430  */
431 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
432 /**
433  * The filter supports multithreading by splitting frames into multiple parts
434  * and processing them concurrently.
435  */
436 #define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
437 /**
438  * Some filters support a generic "enable" expression option that can be used
439  * to enable or disable a filter in the timeline. Filters supporting this
440  * option have this flag set. When the enable expression is false, the default
441  * no-op filter_frame() function is called in place of the filter_frame()
442  * callback defined on each input pad, thus the frame is passed unchanged to
443  * the next filters.
444  */
445 #define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC (1 << 16)
446 /**
447  * Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will
448  * have its filter_frame() callback(s) called as usual even when the enable
449  * expression is false. The filter will disable filtering within the
450  * filter_frame() callback(s) itself, for example executing code depending on
451  * the AVFilterContext->is_disabled value.
452  */
453 #define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL (1 << 17)
454 /**
455  * Handy mask to test whether the filter supports or no the timeline feature
456  * (internally or generically).
457  */
458 #define AVFILTER_FLAG_SUPPORT_TIMELINE (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
459 
460 /**
461  * Filter definition. This defines the pads a filter contains, and all the
462  * callback functions used to interact with the filter.
463  */
464 typedef struct AVFilter {
465  /**
466  * Filter name. Must be non-NULL and unique among filters.
467  */
468  const char *name;
469 
470  /**
471  * A description of the filter. May be NULL.
472  *
473  * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
474  */
475  const char *description;
476 
477  /**
478  * List of inputs, terminated by a zeroed element.
479  *
480  * NULL if there are no (static) inputs. Instances of filters with
481  * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
482  * this list.
483  */
485  /**
486  * List of outputs, terminated by a zeroed element.
487  *
488  * NULL if there are no (static) outputs. Instances of filters with
489  * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
490  * this list.
491  */
493 
494  /**
495  * A class for the private data, used to declare filter private AVOptions.
496  * This field is NULL for filters that do not declare any options.
497  *
498  * If this field is non-NULL, the first member of the filter private data
499  * must be a pointer to AVClass, which will be set by libavfilter generic
500  * code to this class.
501  */
503 
504  /**
505  * A combination of AVFILTER_FLAG_*
506  */
507  int flags;
508 
509  /*****************************************************************
510  * All fields below this line are not part of the public API. They
511  * may not be used outside of libavfilter and can be changed and
512  * removed at will.
513  * New public fields should be added right above.
514  *****************************************************************
515  */
516 
517  /**
518  * Filter initialization function.
519  *
520  * This callback will be called only once during the filter lifetime, after
521  * all the options have been set, but before links between filters are
522  * established and format negotiation is done.
523  *
524  * Basic filter initialization should be done here. Filters with dynamic
525  * inputs and/or outputs should create those inputs/outputs here based on
526  * provided options. No more changes to this filter's inputs/outputs can be
527  * done after this callback.
528  *
529  * This callback must not assume that the filter links exist or frame
530  * parameters are known.
531  *
532  * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
533  * initialization fails, so this callback does not have to clean up on
534  * failure.
535  *
536  * @return 0 on success, a negative AVERROR on failure
537  */
538  int (*init)(AVFilterContext *ctx);
539 
540  /**
541  * Should be set instead of @ref AVFilter.init "init" by the filters that
542  * want to pass a dictionary of AVOptions to nested contexts that are
543  * allocated during init.
544  *
545  * On return, the options dict should be freed and replaced with one that
546  * contains all the options which could not be processed by this filter (or
547  * with NULL if all the options were processed).
548  *
549  * Otherwise the semantics is the same as for @ref AVFilter.init "init".
550  */
552 
553  /**
554  * Filter uninitialization function.
555  *
556  * Called only once right before the filter is freed. Should deallocate any
557  * memory held by the filter, release any buffer references, etc. It does
558  * not need to deallocate the AVFilterContext.priv memory itself.
559  *
560  * This callback may be called even if @ref AVFilter.init "init" was not
561  * called or failed, so it must be prepared to handle such a situation.
562  */
564 
565  /**
566  * Query formats supported by the filter on its inputs and outputs.
567  *
568  * This callback is called after the filter is initialized (so the inputs
569  * and outputs are fixed), shortly before the format negotiation. This
570  * callback may be called more than once.
571  *
572  * This callback must set AVFilterLink.out_formats on every input link and
573  * AVFilterLink.in_formats on every output link to a list of pixel/sample
574  * formats that the filter supports on that link. For audio links, this
575  * filter must also set @ref AVFilterLink.in_samplerates "in_samplerates" /
576  * @ref AVFilterLink.out_samplerates "out_samplerates" and
577  * @ref AVFilterLink.in_channel_layouts "in_channel_layouts" /
578  * @ref AVFilterLink.out_channel_layouts "out_channel_layouts" analogously.
579  *
580  * This callback may be NULL for filters with one input, in which case
581  * libavfilter assumes that it supports all input formats and preserves
582  * them on output.
583  *
584  * @return zero on success, a negative value corresponding to an
585  * AVERROR code otherwise
586  */
588 
589  int priv_size; ///< size of private data to allocate for the filter
590 
591  /**
592  * Used by the filter registration system. Must not be touched by any other
593  * code.
594  */
595  struct AVFilter *next;
596 
597  /**
598  * Make the filter instance process a command.
599  *
600  * @param cmd the command to process, for handling simplicity all commands must be alphanumeric only
601  * @param arg the argument for the command
602  * @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.
603  * @param flags if AVFILTER_CMD_FLAG_FAST is set and the command would be
604  * time consuming then a filter should treat it like an unsupported command
605  *
606  * @returns >=0 on success otherwise an error code.
607  * AVERROR(ENOSYS) on unsupported commands
608  */
609  int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);
610 
611  /**
612  * Filter initialization function, alternative to the init()
613  * callback. Args contains the user-supplied parameters, opaque is
614  * used for providing binary data.
615  */
616  int (*init_opaque)(AVFilterContext *ctx, void *opaque);
617 } AVFilter;
618 
619 /**
620  * Process multiple parts of the frame concurrently.
621  */
622 #define AVFILTER_THREAD_SLICE (1 << 0)
623 
624 typedef struct AVFilterInternal AVFilterInternal;
625 
626 /** An instance of a filter */
628  const AVClass *av_class; ///< needed for av_log() and filters common options
629 
630  const AVFilter *filter; ///< the AVFilter of which this is an instance
631 
632  char *name; ///< name of this filter instance
633 
634  AVFilterPad *input_pads; ///< array of input pads
635  AVFilterLink **inputs; ///< array of pointers to input links
636 #if FF_API_FOO_COUNT
637  attribute_deprecated unsigned input_count; ///< @deprecated use nb_inputs
638 #endif
639  unsigned nb_inputs; ///< number of input pads
640 
641  AVFilterPad *output_pads; ///< array of output pads
642  AVFilterLink **outputs; ///< array of pointers to output links
643 #if FF_API_FOO_COUNT
644  attribute_deprecated unsigned output_count; ///< @deprecated use nb_outputs
645 #endif
646  unsigned nb_outputs; ///< number of output pads
647 
648  void *priv; ///< private data for use by the filter
649 
650  struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
651 
652  /**
653  * Type of multithreading being allowed/used. A combination of
654  * AVFILTER_THREAD_* flags.
655  *
656  * May be set by the caller before initializing the filter to forbid some
657  * or all kinds of multithreading for this filter. The default is allowing
658  * everything.
659  *
660  * When the filter is initialized, this field is combined using bit AND with
661  * AVFilterGraph.thread_type to get the final mask used for determining
662  * allowed threading types. I.e. a threading type needs to be set in both
663  * to be allowed.
664  *
665  * After the filter is initialzed, libavfilter sets this field to the
666  * threading type that is actually used (0 for no multithreading).
667  */
669 
670  /**
671  * An opaque struct for libavfilter internal use.
672  */
673  AVFilterInternal *internal;
674 
676 
677  char *enable_str; ///< enable expression string
678  void *enable; ///< parsed expression (AVExpr*)
679  double *var_values; ///< variable values for the enable expression
680  int is_disabled; ///< the enabled state from the last expression evaluation
681 };
682 
683 /**
684  * A link between two filters. This contains pointers to the source and
685  * destination filters between which this link exists, and the indexes of
686  * the pads involved. In addition, this link also contains the parameters
687  * which have been negotiated and agreed upon between the filter, such as
688  * image dimensions, format, etc.
689  */
690 struct AVFilterLink {
691  AVFilterContext *src; ///< source filter
692  AVFilterPad *srcpad; ///< output pad on the source filter
693 
694  AVFilterContext *dst; ///< dest filter
695  AVFilterPad *dstpad; ///< input pad on the dest filter
696 
697  enum AVMediaType type; ///< filter media type
698 
699  /* These parameters apply only to video */
700  int w; ///< agreed upon image width
701  int h; ///< agreed upon image height
702  AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
703  /* These parameters apply only to audio */
704  uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
705  int sample_rate; ///< samples per second
706 
707  int format; ///< agreed upon media format
708 
709  /**
710  * Define the time base used by the PTS of the frames/samples
711  * which will pass through this link.
712  * During the configuration stage, each filter is supposed to
713  * change only the output timebase, while the timebase of the
714  * input link is assumed to be an unchangeable property.
715  */
717 
718  /*****************************************************************
719  * All fields below this line are not part of the public API. They
720  * may not be used outside of libavfilter and can be changed and
721  * removed at will.
722  * New public fields should be added right above.
723  *****************************************************************
724  */
725  /**
726  * Lists of formats and channel layouts supported by the input and output
727  * filters respectively. These lists are used for negotiating the format
728  * to actually be used, which will be loaded into the format and
729  * channel_layout members, above, when chosen.
730  *
731  */
734 
735  /**
736  * Lists of channel layouts and sample rates used for automatic
737  * negotiation.
738  */
743 
744  /**
745  * Audio only, the destination filter sets this to a non-zero value to
746  * request that buffers with the given number of samples should be sent to
747  * it. AVFilterPad.needs_fifo must also be set on the corresponding input
748  * pad.
749  * Last buffer before EOF will be padded with silence.
750  */
752 
753  /** stage of the initialization of the link properties (dimensions, etc) */
754  enum {
755  AVLINK_UNINIT = 0, ///< not started
756  AVLINK_STARTINIT, ///< started, but incomplete
757  AVLINK_INIT ///< complete
758  } init_state;
759 
761 
762  /**
763  * Graph the filter belongs to.
764  */
766 
767  /**
768  * Current timestamp of the link, as defined by the most recent
769  * frame(s), in AV_TIME_BASE units.
770  */
771  int64_t current_pts;
772 
773  /**
774  * Index in the age array.
775  */
777 
778  /**
779  * Frame rate of the stream on the link, or 1/0 if unknown;
780  * if left to 0/0, will be automatically be copied from the first input
781  * of the source filter if it exists.
782  *
783  * Sources should set it to the best estimation of the real frame rate.
784  * Filters should update it if necessary depending on their function.
785  * Sinks can use it to set a default output frame rate.
786  * It is similar to the r_frame_rate field in AVStream.
787  */
789 
790  /**
791  * Buffer partially filled with samples to achieve a fixed/minimum size.
792  */
794 
795  /**
796  * Size of the partial buffer to allocate.
797  * Must be between min_samples and max_samples.
798  */
800 
801  /**
802  * Minimum number of samples to filter at once. If filter_frame() is
803  * called with fewer samples, it will accumulate them in partial_buf.
804  * This field and the related ones must not be changed after filtering
805  * has started.
806  * If 0, all related fields are ignored.
807  */
809 
810  /**
811  * Maximum number of samples to filter at once. If filter_frame() is
812  * called with more samples, it will split them.
813  */
815 
816  /**
817  * The buffer reference currently being received across the link by the
818  * destination filter. This is used internally by the filter system to
819  * allow automatic copying of buffers which do not have sufficient
820  * permissions for the destination. This should not be accessed directly
821  * by the filters.
822  */
823  AVFilterBufferRef *cur_buf_copy;
824 
825  /**
826  * True if the link is closed.
827  * If set, all attemps of start_frame, filter_frame or request_frame
828  * will fail with AVERROR_EOF, and if necessary the reference will be
829  * destroyed.
830  * If request_frame returns AVERROR_EOF, this flag is set on the
831  * corresponding link.
832  * It can be set also be set by either the source or the destination
833  * filter.
834  */
835  int closed;
836 
837  /**
838  * Number of channels.
839  */
840  int channels;
841 
842  /**
843  * True if a frame is being requested on the link.
844  * Used internally by the framework.
845  */
846  unsigned frame_requested;
847 
848  /**
849  * Link processing flags.
850  */
851  unsigned flags;
852 
853  /**
854  * Number of past frames sent through the link.
855  */
856  int64_t frame_count;
857 };
858 
859 /**
860  * Link two filters together.
861  *
862  * @param src the source filter
863  * @param srcpad index of the output pad on the source filter
864  * @param dst the destination filter
865  * @param dstpad index of the input pad on the destination filter
866  * @return zero on success
867  */
868 int avfilter_link(AVFilterContext *src, unsigned srcpad,
869  AVFilterContext *dst, unsigned dstpad);
870 
871 /**
872  * Free the link in *link, and set its pointer to NULL.
873  */
874 void avfilter_link_free(AVFilterLink **link);
875 
876 /**
877  * Get the number of channels of a link.
878  */
880 
881 /**
882  * Set the closed field of a link.
883  */
884 void avfilter_link_set_closed(AVFilterLink *link, int closed);
885 
886 /**
887  * Negotiate the media format, dimensions, etc of all inputs to a filter.
888  *
889  * @param filter the filter to negotiate the properties for its inputs
890  * @return zero on successful negotiation
891  */
893 
894 #if FF_API_AVFILTERBUFFER
895 /**
896  * Create a buffer reference wrapped around an already allocated image
897  * buffer.
898  *
899  * @param data pointers to the planes of the image to reference
900  * @param linesize linesizes for the planes of the image to reference
901  * @param perms the required access permissions
902  * @param w the width of the image specified by the data and linesize arrays
903  * @param h the height of the image specified by the data and linesize arrays
904  * @param format the pixel format of the image specified by the data and linesize arrays
905  */
907 AVFilterBufferRef *
908 avfilter_get_video_buffer_ref_from_arrays(uint8_t * const data[4], const int linesize[4], int perms,
909  int w, int h, enum AVPixelFormat format);
910 
911 /**
912  * Create an audio buffer reference wrapped around an already
913  * allocated samples buffer.
914  *
915  * See avfilter_get_audio_buffer_ref_from_arrays_channels() for a version
916  * that can handle unknown channel layouts.
917  *
918  * @param data pointers to the samples plane buffers
919  * @param linesize linesize for the samples plane buffers
920  * @param perms the required access permissions
921  * @param nb_samples number of samples per channel
922  * @param sample_fmt the format of each sample in the buffer to allocate
923  * @param channel_layout the channel layout of the buffer
924  */
926 AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
927  int linesize,
928  int perms,
929  int nb_samples,
930  enum AVSampleFormat sample_fmt,
931  uint64_t channel_layout);
932 /**
933  * Create an audio buffer reference wrapped around an already
934  * allocated samples buffer.
935  *
936  * @param data pointers to the samples plane buffers
937  * @param linesize linesize for the samples plane buffers
938  * @param perms the required access permissions
939  * @param nb_samples number of samples per channel
940  * @param sample_fmt the format of each sample in the buffer to allocate
941  * @param channels the number of channels of the buffer
942  * @param channel_layout the channel layout of the buffer,
943  * must be either 0 or consistent with channels
944  */
946 AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays_channels(uint8_t **data,
947  int linesize,
948  int perms,
949  int nb_samples,
950  enum AVSampleFormat sample_fmt,
951  int channels,
952  uint64_t channel_layout);
953 
954 #endif
955 
956 
957 #define AVFILTER_CMD_FLAG_ONE 1 ///< Stop once a filter understood the command (for target=all for example), fast filters are favored automatically
958 #define AVFILTER_CMD_FLAG_FAST 2 ///< Only execute command when its fast (like a video out that supports contrast adjustment in hw)
959 
960 /**
961  * Make the filter instance process a command.
962  * It is recommended to use avfilter_graph_send_command().
963  */
964 int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
965 
966 /** Initialize the filter system. Register all builtin filters. */
967 void avfilter_register_all(void);
968 
969 #if FF_API_OLD_FILTER_REGISTER
970 /** Uninitialize the filter system. Unregister all filters. */
972 void avfilter_uninit(void);
973 #endif
974 
975 /**
976  * Register a filter. This is only needed if you plan to use
977  * avfilter_get_by_name later to lookup the AVFilter structure by name. A
978  * filter can still by instantiated with avfilter_graph_alloc_filter even if it
979  * is not registered.
980  *
981  * @param filter the filter to register
982  * @return 0 if the registration was successful, a negative value
983  * otherwise
984  */
986 
987 /**
988  * Get a filter definition matching the given name.
989  *
990  * @param name the filter name to find
991  * @return the filter definition, if any matching one is registered.
992  * NULL if none found.
993  */
994 AVFilter *avfilter_get_by_name(const char *name);
995 
996 /**
997  * Iterate over all registered filters.
998  * @return If prev is non-NULL, next registered filter after prev or NULL if
999  * prev is the last filter. If prev is NULL, return the first registered filter.
1000  */
1001 const AVFilter *avfilter_next(const AVFilter *prev);
1002 
1003 #if FF_API_OLD_FILTER_REGISTER
1004 /**
1005  * If filter is NULL, returns a pointer to the first registered filter pointer,
1006  * if filter is non-NULL, returns the next pointer after filter.
1007  * If the returned pointer points to NULL, the last registered filter
1008  * was already reached.
1009  * @deprecated use avfilter_next()
1010  */
1012 AVFilter **av_filter_next(AVFilter **filter);
1013 #endif
1014 
1015 #if FF_API_AVFILTER_OPEN
1016 /**
1017  * Create a filter instance.
1018  *
1019  * @param filter_ctx put here a pointer to the created filter context
1020  * on success, NULL on failure
1021  * @param filter the filter to create an instance of
1022  * @param inst_name Name to give to the new instance. Can be NULL for none.
1023  * @return >= 0 in case of success, a negative error code otherwise
1024  * @deprecated use avfilter_graph_alloc_filter() instead
1025  */
1027 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
1028 #endif
1029 
1030 
1031 #if FF_API_AVFILTER_INIT_FILTER
1032 /**
1033  * Initialize a filter.
1034  *
1035  * @param filter the filter to initialize
1036  * @param args A string of parameters to use when initializing the filter.
1037  * The format and meaning of this string varies by filter.
1038  * @param opaque Any extra non-string data needed by the filter. The meaning
1039  * of this parameter varies by filter.
1040  * @return zero on success
1041  */
1043 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
1044 #endif
1045 
1046 /**
1047  * Initialize a filter with the supplied parameters.
1048  *
1049  * @param ctx uninitialized filter context to initialize
1050  * @param args Options to initialize the filter with. This must be a
1051  * ':'-separated list of options in the 'key=value' form.
1052  * May be NULL if the options have been set directly using the
1053  * AVOptions API or there are no options that need to be set.
1054  * @return 0 on success, a negative AVERROR on failure
1055  */
1056 int avfilter_init_str(AVFilterContext *ctx, const char *args);
1057 
1058 /**
1059  * Initialize a filter with the supplied dictionary of options.
1060  *
1061  * @param ctx uninitialized filter context to initialize
1062  * @param options An AVDictionary filled with options for this filter. On
1063  * return this parameter will be destroyed and replaced with
1064  * a dict containing options that were not found. This dictionary
1065  * must be freed by the caller.
1066  * May be NULL, then this function is equivalent to
1067  * avfilter_init_str() with the second parameter set to NULL.
1068  * @return 0 on success, a negative AVERROR on failure
1069  *
1070  * @note This function and avfilter_init_str() do essentially the same thing,
1071  * the difference is in manner in which the options are passed. It is up to the
1072  * calling code to choose whichever is more preferable. The two functions also
1073  * behave differently when some of the provided options are not declared as
1074  * supported by the filter. In such a case, avfilter_init_str() will fail, but
1075  * this function will leave those extra options in the options AVDictionary and
1076  * continue as usual.
1077  */
1079 
1080 /**
1081  * Free a filter context. This will also remove the filter from its
1082  * filtergraph's list of filters.
1083  *
1084  * @param filter the filter to free
1085  */
1087 
1088 /**
1089  * Insert a filter in the middle of an existing link.
1090  *
1091  * @param link the link into which the filter should be inserted
1092  * @param filt the filter to be inserted
1093  * @param filt_srcpad_idx the input pad on the filter to connect
1094  * @param filt_dstpad_idx the output pad on the filter to connect
1095  * @return zero on success
1096  */
1098  unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
1099 
1100 #if FF_API_AVFILTERBUFFER
1101 /**
1102  * Copy the frame properties of src to dst, without copying the actual
1103  * image data.
1104  *
1105  * @return 0 on success, a negative number on error.
1106  */
1108 int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
1109 
1110 /**
1111  * Copy the frame properties and data pointers of src to dst, without copying
1112  * the actual data.
1113  *
1114  * @return 0 on success, a negative number on error.
1115  */
1117 int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src);
1118 #endif
1119 
1120 /**
1121  * @return AVClass for AVFilterContext.
1122  *
1123  * @see av_opt_find().
1124  */
1125 const AVClass *avfilter_get_class(void);
1126 
1128 
1129 /**
1130  * A function pointer passed to the @ref AVFilterGraph.execute callback to be
1131  * executed multiple times, possibly in parallel.
1132  *
1133  * @param ctx the filter context the job belongs to
1134  * @param arg an opaque parameter passed through from @ref
1135  * AVFilterGraph.execute
1136  * @param jobnr the index of the job being executed
1137  * @param nb_jobs the total number of jobs
1138  *
1139  * @return 0 on success, a negative AVERROR on error
1140  */
1141 typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
1142 
1143 /**
1144  * A function executing multiple jobs, possibly in parallel.
1145  *
1146  * @param ctx the filter context to which the jobs belong
1147  * @param func the function to be called multiple times
1148  * @param arg the argument to be passed to func
1149  * @param ret a nb_jobs-sized array to be filled with return values from each
1150  * invocation of func
1151  * @param nb_jobs the number of jobs to execute
1152  *
1153  * @return 0 on success, a negative AVERROR on error
1154  */
1156  void *arg, int *ret, int nb_jobs);
1157 
1158 typedef struct AVFilterGraph {
1160 #if FF_API_FOO_COUNT
1162  unsigned filter_count_unused;
1163 #endif
1165 #if !FF_API_FOO_COUNT
1166  unsigned nb_filters;
1167 #endif
1168 
1169  char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
1170  char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
1171 #if FF_API_FOO_COUNT
1172  unsigned nb_filters;
1173 #endif
1174 
1175  /**
1176  * Type of multithreading allowed for filters in this graph. A combination
1177  * of AVFILTER_THREAD_* flags.
1178  *
1179  * May be set by the caller at any point, the setting will apply to all
1180  * filters initialized after that. The default is allowing everything.
1181  *
1182  * When a filter in this graph is initialized, this field is combined using
1183  * bit AND with AVFilterContext.thread_type to get the final mask used for
1184  * determining allowed threading types. I.e. a threading type needs to be
1185  * set in both to be allowed.
1186  */
1188 
1189  /**
1190  * Maximum number of threads used by filters in this graph. May be set by
1191  * the caller before adding any filters to the filtergraph. Zero (the
1192  * default) means that the number of threads is determined automatically.
1193  */
1195 
1196  /**
1197  * Opaque object for libavfilter internal use.
1198  */
1200 
1201  /**
1202  * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
1203  * be used from callbacks like @ref AVFilterGraph.execute.
1204  * Libavfilter will not touch this field in any way.
1205  */
1206  void *opaque;
1207 
1208  /**
1209  * This callback may be set by the caller immediately after allocating the
1210  * graph and before adding any filters to it, to provide a custom
1211  * multithreading implementation.
1212  *
1213  * If set, filters with slice threading capability will call this callback
1214  * to execute multiple jobs in parallel.
1215  *
1216  * If this field is left unset, libavfilter will use its internal
1217  * implementation, which may or may not be multithreaded depending on the
1218  * platform and build options.
1219  */
1221 
1222  char *aresample_swr_opts; ///< swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
1223 
1224  /**
1225  * Private fields
1226  *
1227  * The following fields are for internal use only.
1228  * Their type, offset, number and semantic can change without notice.
1229  */
1230 
1233 
1235 } AVFilterGraph;
1236 
1237 /**
1238  * Allocate a filter graph.
1239  */
1241 
1242 /**
1243  * Create a new filter instance in a filter graph.
1244  *
1245  * @param graph graph in which the new filter will be used
1246  * @param filter the filter to create an instance of
1247  * @param name Name to give to the new instance (will be copied to
1248  * AVFilterContext.name). This may be used by the caller to identify
1249  * different filters, libavfilter itself assigns no semantics to
1250  * this parameter. May be NULL.
1251  *
1252  * @return the context of the newly created filter instance (note that it is
1253  * also retrievable directly through AVFilterGraph.filters or with
1254  * avfilter_graph_get_filter()) on success or NULL or failure.
1255  */
1257  const AVFilter *filter,
1258  const char *name);
1259 
1260 /**
1261  * Get a filter instance with name name from graph.
1262  *
1263  * @return the pointer to the found filter instance or NULL if it
1264  * cannot be found.
1265  */
1267 
1268 #if FF_API_AVFILTER_OPEN
1269 /**
1270  * Add an existing filter instance to a filter graph.
1271  *
1272  * @param graphctx the filter graph
1273  * @param filter the filter to be added
1274  *
1275  * @deprecated use avfilter_graph_alloc_filter() to allocate a filter in a
1276  * filter graph
1277  */
1279 int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
1280 #endif
1281 
1282 /**
1283  * Create and add a filter instance into an existing graph.
1284  * The filter instance is created from the filter filt and inited
1285  * with the parameters args and opaque.
1286  *
1287  * In case of success put in *filt_ctx the pointer to the created
1288  * filter instance, otherwise set *filt_ctx to NULL.
1289  *
1290  * @param name the instance name to give to the created filter instance
1291  * @param graph_ctx the filter graph
1292  * @return a negative AVERROR error code in case of failure, a non
1293  * negative value otherwise
1294  */
1296  const char *name, const char *args, void *opaque,
1297  AVFilterGraph *graph_ctx);
1298 
1299 /**
1300  * Enable or disable automatic format conversion inside the graph.
1301  *
1302  * Note that format conversion can still happen inside explicitly inserted
1303  * scale and aresample filters.
1304  *
1305  * @param flags any of the AVFILTER_AUTO_CONVERT_* constants
1306  */
1307 void avfilter_graph_set_auto_convert(AVFilterGraph *graph, unsigned flags);
1308 
1309 enum {
1310  AVFILTER_AUTO_CONVERT_ALL = 0, /**< all automatic conversions enabled */
1311  AVFILTER_AUTO_CONVERT_NONE = -1, /**< all automatic conversions disabled */
1312 };
1313 
1314 /**
1315  * Check validity and configure all the links and formats in the graph.
1316  *
1317  * @param graphctx the filter graph
1318  * @param log_ctx context used for logging
1319  * @return >= 0 in case of success, a negative AVERROR code otherwise
1320  */
1321 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
1322 
1323 /**
1324  * Free a graph, destroy its links, and set *graph to NULL.
1325  * If *graph is NULL, do nothing.
1326  */
1327 void avfilter_graph_free(AVFilterGraph **graph);
1328 
1329 /**
1330  * A linked-list of the inputs/outputs of the filter chain.
1331  *
1332  * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
1333  * where it is used to communicate open (unlinked) inputs and outputs from and
1334  * to the caller.
1335  * This struct specifies, per each not connected pad contained in the graph, the
1336  * filter context and the pad index required for establishing a link.
1337  */
1338 typedef struct AVFilterInOut {
1339  /** unique name for this input/output in the list */
1340  char *name;
1341 
1342  /** filter context associated to this input/output */
1344 
1345  /** index of the filt_ctx pad to use for linking */
1346  int pad_idx;
1347 
1348  /** next input/input in the list, NULL if this is the last */
1350 } AVFilterInOut;
1351 
1352 /**
1353  * Allocate a single AVFilterInOut entry.
1354  * Must be freed with avfilter_inout_free().
1355  * @return allocated AVFilterInOut on success, NULL on failure.
1356  */
1358 
1359 /**
1360  * Free the supplied list of AVFilterInOut and set *inout to NULL.
1361  * If *inout is NULL, do nothing.
1362  */
1363 void avfilter_inout_free(AVFilterInOut **inout);
1364 
1365 #if AV_HAVE_INCOMPATIBLE_LIBAV_ABI || !FF_API_OLD_GRAPH_PARSE
1366 /**
1367  * Add a graph described by a string to a graph.
1368  *
1369  * @note The caller must provide the lists of inputs and outputs,
1370  * which therefore must be known before calling the function.
1371  *
1372  * @note The inputs parameter describes inputs of the already existing
1373  * part of the graph; i.e. from the point of view of the newly created
1374  * part, they are outputs. Similarly the outputs parameter describes
1375  * outputs of the already existing filters, which are provided as
1376  * inputs to the parsed filters.
1377  *
1378  * @param graph the filter graph where to link the parsed grap context
1379  * @param filters string to be parsed
1380  * @param inputs linked list to the inputs of the graph
1381  * @param outputs linked list to the outputs of the graph
1382  * @return zero on success, a negative AVERROR code on error
1383  */
1384 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
1386  void *log_ctx);
1387 #else
1388 /**
1389  * Add a graph described by a string to a graph.
1390  *
1391  * @param graph the filter graph where to link the parsed graph context
1392  * @param filters string to be parsed
1393  * @param inputs pointer to a linked list to the inputs of the graph, may be NULL.
1394  * If non-NULL, *inputs is updated to contain the list of open inputs
1395  * after the parsing, should be freed with avfilter_inout_free().
1396  * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
1397  * If non-NULL, *outputs is updated to contain the list of open outputs
1398  * after the parsing, should be freed with avfilter_inout_free().
1399  * @return non negative on success, a negative AVERROR code on error
1400  * @deprecated Use avfilter_graph_parse_ptr() instead.
1401  */
1403 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
1405  void *log_ctx);
1406 #endif
1407 
1408 /**
1409  * Add a graph described by a string to a graph.
1410  *
1411  * @param graph the filter graph where to link the parsed graph context
1412  * @param filters string to be parsed
1413  * @param inputs pointer to a linked list to the inputs of the graph, may be NULL.
1414  * If non-NULL, *inputs is updated to contain the list of open inputs
1415  * after the parsing, should be freed with avfilter_inout_free().
1416  * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
1417  * If non-NULL, *outputs is updated to contain the list of open outputs
1418  * after the parsing, should be freed with avfilter_inout_free().
1419  * @return non negative on success, a negative AVERROR code on error
1420  */
1421 int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
1423  void *log_ctx);
1424 
1425 /**
1426  * Add a graph described by a string to a graph.
1427  *
1428  * @param[in] graph the filter graph where to link the parsed graph context
1429  * @param[in] filters string to be parsed
1430  * @param[out] inputs a linked list of all free (unlinked) inputs of the
1431  * parsed graph will be returned here. It is to be freed
1432  * by the caller using avfilter_inout_free().
1433  * @param[out] outputs a linked list of all free (unlinked) outputs of the
1434  * parsed graph will be returned here. It is to be freed by the
1435  * caller using avfilter_inout_free().
1436  * @return zero on success, a negative AVERROR code on error
1437  *
1438  * @note This function returns the inputs and outputs that are left
1439  * unlinked after parsing the graph and the caller then deals with
1440  * them.
1441  * @note This function makes no reference whatsoever to already
1442  * existing parts of the graph and the inputs parameter will on return
1443  * contain inputs of the newly parsed part of the graph. Analogously
1444  * the outputs parameter will contain outputs of the newly created
1445  * filters.
1446  */
1447 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
1450 
1451 /**
1452  * Send a command to one or more filter instances.
1453  *
1454  * @param graph the filter graph
1455  * @param target the filter(s) to which the command should be sent
1456  * "all" sends to all filters
1457  * otherwise it can be a filter or filter instance name
1458  * which will send the command to all matching filters.
1459  * @param cmd the command to send, for handling simplicity all commands must be alphanumeric only
1460  * @param arg the argument for the command
1461  * @param res a buffer with size res_size where the filter(s) can return a response.
1462  *
1463  * @returns >=0 on success otherwise an error code.
1464  * AVERROR(ENOSYS) on unsupported commands
1465  */
1466 int avfilter_graph_send_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, char *res, int res_len, int flags);
1467 
1468 /**
1469  * Queue a command for one or more filter instances.
1470  *
1471  * @param graph the filter graph
1472  * @param target the filter(s) to which the command should be sent
1473  * "all" sends to all filters
1474  * otherwise it can be a filter or filter instance name
1475  * which will send the command to all matching filters.
1476  * @param cmd the command to sent, for handling simplicity all commands must be alphanummeric only
1477  * @param arg the argument for the command
1478  * @param ts time at which the command should be sent to the filter
1479  *
1480  * @note As this executes commands after this function returns, no return code
1481  * from the filter is provided, also AVFILTER_CMD_FLAG_ONE is not supported.
1482  */
1483 int avfilter_graph_queue_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, int flags, double ts);
1484 
1485 
1486 /**
1487  * Dump a graph into a human-readable string representation.
1488  *
1489  * @param graph the graph to dump
1490  * @param options formatting options; currently ignored
1491  * @return a string, or NULL in case of memory allocation failure;
1492  * the string must be freed using av_free
1493  */
1494 char *avfilter_graph_dump(AVFilterGraph *graph, const char *options);
1495 
1496 /**
1497  * Request a frame on the oldest sink link.
1498  *
1499  * If the request returns AVERROR_EOF, try the next.
1500  *
1501  * Note that this function is not meant to be the sole scheduling mechanism
1502  * of a filtergraph, only a convenience function to help drain a filtergraph
1503  * in a balanced way under normal circumstances.
1504  *
1505  * Also note that AVERROR_EOF does not mean that frames did not arrive on
1506  * some of the sinks during the process.
1507  * When there are multiple sink links, in case the requested link
1508  * returns an EOF, this may cause a filter to flush pending frames
1509  * which are sent to another sink link, although unrequested.
1510  *
1511  * @return the return value of ff_request_frame(),
1512  * or AVERROR_EOF if all links returned AVERROR_EOF
1513  */
1515 
1516 /**
1517  * @}
1518  */
1519 
1520 #endif /* AVFILTER_AVFILTER_H */