FFmpeg
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
33  * Graph-based frame editing library.
34  *
35  * @{
36  */
37 
38 #include <stddef.h>
39 
40 #include "libavutil/attributes.h"
41 #include "libavutil/avutil.h"
42 #include "libavutil/buffer.h"
43 #include "libavutil/dict.h"
44 #include "libavutil/frame.h"
45 #include "libavutil/log.h"
46 #include "libavutil/samplefmt.h"
47 #include "libavutil/pixfmt.h"
48 #include "libavutil/rational.h"
49 
51 #ifndef HAVE_AV_CONFIG_H
52 /* When included as part of the ffmpeg build, only include the major version
53  * to avoid unnecessary rebuilds. When included externally, keep including
54  * the full version information. */
55 #include "libavfilter/version.h"
56 #endif
57 
58 /**
59  * Return the LIBAVFILTER_VERSION_INT constant.
60  */
61 unsigned avfilter_version(void);
62 
63 /**
64  * Return the libavfilter build-time configuration.
65  */
66 const char *avfilter_configuration(void);
67 
68 /**
69  * Return the libavfilter license.
70  */
71 const char *avfilter_license(void);
72 
73 typedef struct AVFilterContext AVFilterContext;
74 typedef struct AVFilterLink AVFilterLink;
75 typedef struct AVFilterPad AVFilterPad;
76 typedef struct AVFilterFormats AVFilterFormats;
78 
79 /**
80  * Get the name of an AVFilterPad.
81  *
82  * @param pads an array of AVFilterPads
83  * @param pad_idx index of the pad in the array; it is the caller's
84  * responsibility to ensure the index is valid
85  *
86  * @return name of the pad_idx'th pad in pads
87  */
88 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
89 
90 /**
91  * Get the type of an AVFilterPad.
92  *
93  * @param pads an array of AVFilterPads
94  * @param pad_idx index of the pad in the array; it is the caller's
95  * responsibility to ensure the index is valid
96  *
97  * @return type of the pad_idx'th pad in pads
98  */
99 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
100 
101 /**
102  * The number of the filter inputs is not determined just by AVFilter.inputs.
103  * The filter might add additional inputs during initialization depending on the
104  * options supplied to it.
105  */
106 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
107 /**
108  * The number of the filter outputs is not determined just by AVFilter.outputs.
109  * The filter might add additional outputs during initialization depending on
110  * the options supplied to it.
111  */
112 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
113 /**
114  * The filter supports multithreading by splitting frames into multiple parts
115  * and processing them concurrently.
116  */
117 #define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
118 /**
119  * The filter is a "metadata" filter - it does not modify the frame data in any
120  * way. It may only affect the metadata (i.e. those fields copied by
121  * av_frame_copy_props()).
122  *
123  * More precisely, this means:
124  * - video: the data of any frame output by the filter must be exactly equal to
125  * some frame that is received on one of its inputs. Furthermore, all frames
126  * produced on a given output must correspond to frames received on the same
127  * input and their order must be unchanged. Note that the filter may still
128  * drop or duplicate the frames.
129  * - audio: the data produced by the filter on any of its outputs (viewed e.g.
130  * as an array of interleaved samples) must be exactly equal to the data
131  * received by the filter on one of its inputs.
132  */
133 #define AVFILTER_FLAG_METADATA_ONLY (1 << 3)
134 /**
135  * Some filters support a generic "enable" expression option that can be used
136  * to enable or disable a filter in the timeline. Filters supporting this
137  * option have this flag set. When the enable expression is false, the default
138  * no-op filter_frame() function is called in place of the filter_frame()
139  * callback defined on each input pad, thus the frame is passed unchanged to
140  * the next filters.
141  */
142 #define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC (1 << 16)
143 /**
144  * Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will
145  * have its filter_frame() callback(s) called as usual even when the enable
146  * expression is false. The filter will disable filtering within the
147  * filter_frame() callback(s) itself, for example executing code depending on
148  * the AVFilterContext->is_disabled value.
149  */
150 #define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL (1 << 17)
151 /**
152  * Handy mask to test whether the filter supports or no the timeline feature
153  * (internally or generically).
154  */
155 #define AVFILTER_FLAG_SUPPORT_TIMELINE (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
156 
157 /**
158  * Filter definition. This defines the pads a filter contains, and all the
159  * callback functions used to interact with the filter.
160  */
161 typedef struct AVFilter {
162  /**
163  * Filter name. Must be non-NULL and unique among filters.
164  */
165  const char *name;
166 
167  /**
168  * A description of the filter. May be NULL.
169  *
170  * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
171  */
172  const char *description;
173 
174  /**
175  * List of static inputs.
176  *
177  * NULL if there are no (static) inputs. Instances of filters with
178  * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
179  * this list.
180  */
182 
183  /**
184  * List of static outputs.
185  *
186  * NULL if there are no (static) outputs. Instances of filters with
187  * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
188  * this list.
189  */
191 
192  /**
193  * A class for the private data, used to declare filter private AVOptions.
194  * This field is NULL for filters that do not declare any options.
195  *
196  * If this field is non-NULL, the first member of the filter private data
197  * must be a pointer to AVClass, which will be set by libavfilter generic
198  * code to this class.
199  */
201 
202  /**
203  * A combination of AVFILTER_FLAG_*
204  */
205  int flags;
206 
207  /*****************************************************************
208  * All fields below this line are not part of the public API. They
209  * may not be used outside of libavfilter and can be changed and
210  * removed at will.
211  * New public fields should be added right above.
212  *****************************************************************
213  */
214 
215  /**
216  * The number of entries in the list of inputs.
217  */
218  uint8_t nb_inputs;
219 
220  /**
221  * The number of entries in the list of outputs.
222  */
223  uint8_t nb_outputs;
224 
225  /**
226  * This field determines the state of the formats union.
227  * It is an enum FilterFormatsState value.
228  */
229  uint8_t formats_state;
230 
231  /**
232  * Filter pre-initialization function
233  *
234  * This callback will be called immediately after the filter context is
235  * allocated, to allow allocating and initing sub-objects.
236  *
237  * If this callback is not NULL, the uninit callback will be called on
238  * allocation failure.
239  *
240  * @return 0 on success,
241  * AVERROR code on failure (but the code will be
242  * dropped and treated as ENOMEM by the calling code)
243  */
245 
246  /**
247  * Filter initialization function.
248  *
249  * This callback will be called only once during the filter lifetime, after
250  * all the options have been set, but before links between filters are
251  * established and format negotiation is done.
252  *
253  * Basic filter initialization should be done here. Filters with dynamic
254  * inputs and/or outputs should create those inputs/outputs here based on
255  * provided options. No more changes to this filter's inputs/outputs can be
256  * done after this callback.
257  *
258  * This callback must not assume that the filter links exist or frame
259  * parameters are known.
260  *
261  * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
262  * initialization fails, so this callback does not have to clean up on
263  * failure.
264  *
265  * @return 0 on success, a negative AVERROR on failure
266  */
268 
269  /**
270  * Filter uninitialization function.
271  *
272  * Called only once right before the filter is freed. Should deallocate any
273  * memory held by the filter, release any buffer references, etc. It does
274  * not need to deallocate the AVFilterContext.priv memory itself.
275  *
276  * This callback may be called even if @ref AVFilter.init "init" was not
277  * called or failed, so it must be prepared to handle such a situation.
278  */
280 
281  /**
282  * The state of the following union is determined by formats_state.
283  * See the documentation of enum FilterFormatsState in internal.h.
284  */
285  union {
286  /**
287  * Query formats supported by the filter on its inputs and outputs.
288  *
289  * This callback is called after the filter is initialized (so the inputs
290  * and outputs are fixed), shortly before the format negotiation. This
291  * callback may be called more than once.
292  *
293  * This callback must set ::AVFilterLink's
294  * @ref AVFilterFormatsConfig.formats "outcfg.formats"
295  * on every input link and
296  * @ref AVFilterFormatsConfig.formats "incfg.formats"
297  * on every output link to a list of pixel/sample formats that the filter
298  * supports on that link.
299  * For audio links, this filter must also set
300  * @ref AVFilterFormatsConfig.samplerates "incfg.samplerates"
301  * /
302  * @ref AVFilterFormatsConfig.samplerates "outcfg.samplerates"
303  * and @ref AVFilterFormatsConfig.channel_layouts "incfg.channel_layouts"
304  * /
305  * @ref AVFilterFormatsConfig.channel_layouts "outcfg.channel_layouts"
306  * analogously.
307  *
308  * This callback must never be NULL if the union is in this state.
309  *
310  * @return zero on success, a negative value corresponding to an
311  * AVERROR code otherwise
312  */
314  /**
315  * A pointer to an array of admissible pixel formats delimited
316  * by AV_PIX_FMT_NONE. The generic code will use this list
317  * to indicate that this filter supports each of these pixel formats,
318  * provided that all inputs and outputs use the same pixel format.
319  *
320  * This list must never be NULL if the union is in this state.
321  * The type of all inputs and outputs of filters using this must
322  * be AVMEDIA_TYPE_VIDEO.
323  */
325  /**
326  * Analogous to pixels, but delimited by AV_SAMPLE_FMT_NONE
327  * and restricted to filters that only have AVMEDIA_TYPE_AUDIO
328  * inputs and outputs.
329  *
330  * In addition to that the generic code will mark all inputs
331  * and all outputs as supporting all sample rates and every
332  * channel count and channel layout, as long as all inputs
333  * and outputs use the same sample rate and channel count/layout.
334  */
336  /**
337  * Equivalent to { pix_fmt, AV_PIX_FMT_NONE } as pixels_list.
338  */
340  /**
341  * Equivalent to { sample_fmt, AV_SAMPLE_FMT_NONE } as samples_list.
342  */
344  } formats;
345 
346  int priv_size; ///< size of private data to allocate for the filter
347 
348  int flags_internal; ///< Additional flags for avfilter internal use only.
349 
350  /**
351  * Make the filter instance process a command.
352  *
353  * @param cmd the command to process, for handling simplicity all commands must be alphanumeric only
354  * @param arg the argument for the command
355  * @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.
356  * @param flags if AVFILTER_CMD_FLAG_FAST is set and the command would be
357  * time consuming then a filter should treat it like an unsupported command
358  *
359  * @returns >=0 on success otherwise an error code.
360  * AVERROR(ENOSYS) on unsupported commands
361  */
362  int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);
363 
364  /**
365  * Filter activation function.
366  *
367  * Called when any processing is needed from the filter, instead of any
368  * filter_frame and request_frame on pads.
369  *
370  * The function must examine inlinks and outlinks and perform a single
371  * step of processing. If there is nothing to do, the function must do
372  * nothing and not return an error. If more steps are or may be
373  * possible, it must use ff_filter_set_ready() to schedule another
374  * activation.
375  */
377 } AVFilter;
378 
379 /**
380  * Get the number of elements in an AVFilter's inputs or outputs array.
381  */
382 unsigned avfilter_filter_pad_count(const AVFilter *filter, int is_output);
383 
384 /**
385  * Process multiple parts of the frame concurrently.
386  */
387 #define AVFILTER_THREAD_SLICE (1 << 0)
388 
389 typedef struct AVFilterInternal AVFilterInternal;
390 
391 /** An instance of a filter */
393  const AVClass *av_class; ///< needed for av_log() and filters common options
394 
395  const AVFilter *filter; ///< the AVFilter of which this is an instance
396 
397  char *name; ///< name of this filter instance
398 
399  AVFilterPad *input_pads; ///< array of input pads
400  AVFilterLink **inputs; ///< array of pointers to input links
401  unsigned nb_inputs; ///< number of input pads
402 
403  AVFilterPad *output_pads; ///< array of output pads
404  AVFilterLink **outputs; ///< array of pointers to output links
405  unsigned nb_outputs; ///< number of output pads
406 
407  void *priv; ///< private data for use by the filter
408 
409  struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
410 
411  /**
412  * Type of multithreading being allowed/used. A combination of
413  * AVFILTER_THREAD_* flags.
414  *
415  * May be set by the caller before initializing the filter to forbid some
416  * or all kinds of multithreading for this filter. The default is allowing
417  * everything.
418  *
419  * When the filter is initialized, this field is combined using bit AND with
420  * AVFilterGraph.thread_type to get the final mask used for determining
421  * allowed threading types. I.e. a threading type needs to be set in both
422  * to be allowed.
423  *
424  * After the filter is initialized, libavfilter sets this field to the
425  * threading type that is actually used (0 for no multithreading).
426  */
428 
429  /**
430  * An opaque struct for libavfilter internal use.
431  */
432  AVFilterInternal *internal;
433 
435 
436  char *enable_str; ///< enable expression string
437  void *enable; ///< parsed expression (AVExpr*)
438  double *var_values; ///< variable values for the enable expression
439  int is_disabled; ///< the enabled state from the last expression evaluation
440 
441  /**
442  * For filters which will create hardware frames, sets the device the
443  * filter should create them in. All other filters will ignore this field:
444  * in particular, a filter which consumes or processes hardware frames will
445  * instead use the hw_frames_ctx field in AVFilterLink to carry the
446  * hardware context information.
447  */
449 
450  /**
451  * Max number of threads allowed in this filter instance.
452  * If <= 0, its value is ignored.
453  * Overrides global number of threads set per filter graph.
454  */
456 
457  /**
458  * Ready status of the filter.
459  * A non-0 value means that the filter needs activating;
460  * a higher value suggests a more urgent activation.
461  */
462  unsigned ready;
463 
464  /**
465  * Sets the number of extra hardware frames which the filter will
466  * allocate on its output links for use in following filters or by
467  * the caller.
468  *
469  * Some hardware filters require all frames that they will use for
470  * output to be defined in advance before filtering starts. For such
471  * filters, any hardware frame pools used for output must therefore be
472  * of fixed size. The extra frames set here are on top of any number
473  * that the filter needs internally in order to operate normally.
474  *
475  * This field must be set before the graph containing this filter is
476  * configured.
477  */
479 };
480 
481 /**
482  * Lists of formats / etc. supported by an end of a link.
483  *
484  * This structure is directly part of AVFilterLink, in two copies:
485  * one for the source filter, one for the destination filter.
486 
487  * These lists are used for negotiating the format to actually be used,
488  * which will be loaded into the format and channel_layout members of
489  * AVFilterLink, when chosen.
490  */
491 typedef struct AVFilterFormatsConfig {
492 
493  /**
494  * List of supported formats (pixel or sample).
495  */
497 
498  /**
499  * Lists of supported sample rates, only for audio.
500  */
502 
503  /**
504  * Lists of supported channel layouts, only for audio.
505  */
507 
509 
510 /**
511  * A link between two filters. This contains pointers to the source and
512  * destination filters between which this link exists, and the indexes of
513  * the pads involved. In addition, this link also contains the parameters
514  * which have been negotiated and agreed upon between the filter, such as
515  * image dimensions, format, etc.
516  *
517  * Applications must not normally access the link structure directly.
518  * Use the buffersrc and buffersink API instead.
519  * In the future, access to the header may be reserved for filters
520  * implementation.
521  */
522 struct AVFilterLink {
523  AVFilterContext *src; ///< source filter
524  AVFilterPad *srcpad; ///< output pad on the source filter
525 
526  AVFilterContext *dst; ///< dest filter
527  AVFilterPad *dstpad; ///< input pad on the dest filter
528 
529  enum AVMediaType type; ///< filter media type
530 
531  /* These parameters apply only to video */
532  int w; ///< agreed upon image width
533  int h; ///< agreed upon image height
534  AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
535  /* These parameters apply only to audio */
536 #if FF_API_OLD_CHANNEL_LAYOUT
537  /**
538  * channel layout of current buffer (see libavutil/channel_layout.h)
539  * @deprecated use ch_layout
540  */
542  uint64_t channel_layout;
543 #endif
544  int sample_rate; ///< samples per second
545 
546  int format; ///< agreed upon media format
547 
548  /**
549  * Define the time base used by the PTS of the frames/samples
550  * which will pass through this link.
551  * During the configuration stage, each filter is supposed to
552  * change only the output timebase, while the timebase of the
553  * input link is assumed to be an unchangeable property.
554  */
556 
557  AVChannelLayout ch_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
558 
559  /*****************************************************************
560  * All fields below this line are not part of the public API. They
561  * may not be used outside of libavfilter and can be changed and
562  * removed at will.
563  * New public fields should be added right above.
564  *****************************************************************
565  */
566 
567  /**
568  * Lists of supported formats / etc. supported by the input filter.
569  */
571 
572  /**
573  * Lists of supported formats / etc. supported by the output filter.
574  */
576 
577  /** stage of the initialization of the link properties (dimensions, etc) */
578  enum {
579  AVLINK_UNINIT = 0, ///< not started
580  AVLINK_STARTINIT, ///< started, but incomplete
581  AVLINK_INIT ///< complete
582  } init_state;
583 
584  /**
585  * Graph the filter belongs to.
586  */
588 
589  /**
590  * Current timestamp of the link, as defined by the most recent
591  * frame(s), in link time_base units.
592  */
593  int64_t current_pts;
594 
595  /**
596  * Current timestamp of the link, as defined by the most recent
597  * frame(s), in AV_TIME_BASE units.
598  */
599  int64_t current_pts_us;
600 
601  /**
602  * Index in the age array.
603  */
605 
606  /**
607  * Frame rate of the stream on the link, or 1/0 if unknown or variable;
608  * if left to 0/0, will be automatically copied from the first input
609  * of the source filter if it exists.
610  *
611  * Sources should set it to the best estimation of the real frame rate.
612  * If the source frame rate is unknown or variable, set this to 1/0.
613  * Filters should update it if necessary depending on their function.
614  * Sinks can use it to set a default output frame rate.
615  * It is similar to the r_frame_rate field in AVStream.
616  */
618 
619  /**
620  * Minimum number of samples to filter at once. If filter_frame() is
621  * called with fewer samples, it will accumulate them in fifo.
622  * This field and the related ones must not be changed after filtering
623  * has started.
624  * If 0, all related fields are ignored.
625  */
627 
628  /**
629  * Maximum number of samples to filter at once. If filter_frame() is
630  * called with more samples, it will split them.
631  */
633 
634  /**
635  * Number of past frames sent through the link.
636  */
638 
639  /**
640  * Number of past samples sent through the link.
641  */
643 
644  /**
645  * A pointer to a FFFramePool struct.
646  */
647  void *frame_pool;
648 
649  /**
650  * True if a frame is currently wanted on the output of this filter.
651  * Set when ff_request_frame() is called by the output,
652  * cleared when a frame is filtered.
653  */
655 
656  /**
657  * For hwaccel pixel formats, this should be a reference to the
658  * AVHWFramesContext describing the frames.
659  */
661 
662 #ifndef FF_INTERNAL_FIELDS
663 
664  /**
665  * Internal structure members.
666  * The fields below this limit are internal for libavfilter's use
667  * and must in no way be accessed by applications.
668  */
669  char reserved[0xF000];
670 
671 #else /* FF_INTERNAL_FIELDS */
672 
673  /**
674  * Queue of frames waiting to be filtered.
675  */
676  FFFrameQueue fifo;
677 
678  /**
679  * If set, the source filter can not generate a frame as is.
680  * The goal is to avoid repeatedly calling the request_frame() method on
681  * the same link.
682  */
683  int frame_blocked_in;
684 
685  /**
686  * Link input status.
687  * If not zero, all attempts of filter_frame will fail with the
688  * corresponding code.
689  */
690  int status_in;
691 
692  /**
693  * Timestamp of the input status change.
694  */
695  int64_t status_in_pts;
696 
697  /**
698  * Link output status.
699  * If not zero, all attempts of request_frame will fail with the
700  * corresponding code.
701  */
702  int status_out;
703 
704 #endif /* FF_INTERNAL_FIELDS */
705 
706 };
707 
708 /**
709  * Link two filters together.
710  *
711  * @param src the source filter
712  * @param srcpad index of the output pad on the source filter
713  * @param dst the destination filter
714  * @param dstpad index of the input pad on the destination filter
715  * @return zero on success
716  */
717 int avfilter_link(AVFilterContext *src, unsigned srcpad,
718  AVFilterContext *dst, unsigned dstpad);
719 
720 /**
721  * Free the link in *link, and set its pointer to NULL.
722  */
724 
725 /**
726  * Negotiate the media format, dimensions, etc of all inputs to a filter.
727  *
728  * @param filter the filter to negotiate the properties for its inputs
729  * @return zero on successful negotiation
730  */
732 
733 #define AVFILTER_CMD_FLAG_ONE 1 ///< Stop once a filter understood the command (for target=all for example), fast filters are favored automatically
734 #define AVFILTER_CMD_FLAG_FAST 2 ///< Only execute command when its fast (like a video out that supports contrast adjustment in hw)
735 
736 /**
737  * Make the filter instance process a command.
738  * It is recommended to use avfilter_graph_send_command().
739  */
740 int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
741 
742 /**
743  * Iterate over all registered filters.
744  *
745  * @param opaque a pointer where libavfilter will store the iteration state. Must
746  * point to NULL to start the iteration.
747  *
748  * @return the next registered filter or NULL when the iteration is
749  * finished
750  */
751 const AVFilter *av_filter_iterate(void **opaque);
752 
753 /**
754  * Get a filter definition matching the given name.
755  *
756  * @param name the filter name to find
757  * @return the filter definition, if any matching one is registered.
758  * NULL if none found.
759  */
760 const AVFilter *avfilter_get_by_name(const char *name);
761 
762 
763 /**
764  * Initialize a filter with the supplied parameters.
765  *
766  * @param ctx uninitialized filter context to initialize
767  * @param args Options to initialize the filter with. This must be a
768  * ':'-separated list of options in the 'key=value' form.
769  * May be NULL if the options have been set directly using the
770  * AVOptions API or there are no options that need to be set.
771  * @return 0 on success, a negative AVERROR on failure
772  */
773 int avfilter_init_str(AVFilterContext *ctx, const char *args);
774 
775 /**
776  * Initialize a filter with the supplied dictionary of options.
777  *
778  * @param ctx uninitialized filter context to initialize
779  * @param options An AVDictionary filled with options for this filter. On
780  * return this parameter will be destroyed and replaced with
781  * a dict containing options that were not found. This dictionary
782  * must be freed by the caller.
783  * May be NULL, then this function is equivalent to
784  * avfilter_init_str() with the second parameter set to NULL.
785  * @return 0 on success, a negative AVERROR on failure
786  *
787  * @note This function and avfilter_init_str() do essentially the same thing,
788  * the difference is in manner in which the options are passed. It is up to the
789  * calling code to choose whichever is more preferable. The two functions also
790  * behave differently when some of the provided options are not declared as
791  * supported by the filter. In such a case, avfilter_init_str() will fail, but
792  * this function will leave those extra options in the options AVDictionary and
793  * continue as usual.
794  */
796 
797 /**
798  * Free a filter context. This will also remove the filter from its
799  * filtergraph's list of filters.
800  *
801  * @param filter the filter to free
802  */
804 
805 /**
806  * Insert a filter in the middle of an existing link.
807  *
808  * @param link the link into which the filter should be inserted
809  * @param filt the filter to be inserted
810  * @param filt_srcpad_idx the input pad on the filter to connect
811  * @param filt_dstpad_idx the output pad on the filter to connect
812  * @return zero on success
813  */
815  unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
816 
817 /**
818  * @return AVClass for AVFilterContext.
819  *
820  * @see av_opt_find().
821  */
822 const AVClass *avfilter_get_class(void);
823 
825 
826 /**
827  * A function pointer passed to the @ref AVFilterGraph.execute callback to be
828  * executed multiple times, possibly in parallel.
829  *
830  * @param ctx the filter context the job belongs to
831  * @param arg an opaque parameter passed through from @ref
832  * AVFilterGraph.execute
833  * @param jobnr the index of the job being executed
834  * @param nb_jobs the total number of jobs
835  *
836  * @return 0 on success, a negative AVERROR on error
837  */
838 typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
839 
840 /**
841  * A function executing multiple jobs, possibly in parallel.
842  *
843  * @param ctx the filter context to which the jobs belong
844  * @param func the function to be called multiple times
845  * @param arg the argument to be passed to func
846  * @param ret a nb_jobs-sized array to be filled with return values from each
847  * invocation of func
848  * @param nb_jobs the number of jobs to execute
849  *
850  * @return 0 on success, a negative AVERROR on error
851  */
853  void *arg, int *ret, int nb_jobs);
854 
855 typedef struct AVFilterGraph {
858  unsigned nb_filters;
859 
860  char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
861 
862  /**
863  * Type of multithreading allowed for filters in this graph. A combination
864  * of AVFILTER_THREAD_* flags.
865  *
866  * May be set by the caller at any point, the setting will apply to all
867  * filters initialized after that. The default is allowing everything.
868  *
869  * When a filter in this graph is initialized, this field is combined using
870  * bit AND with AVFilterContext.thread_type to get the final mask used for
871  * determining allowed threading types. I.e. a threading type needs to be
872  * set in both to be allowed.
873  */
875 
876  /**
877  * Maximum number of threads used by filters in this graph. May be set by
878  * the caller before adding any filters to the filtergraph. Zero (the
879  * default) means that the number of threads is determined automatically.
880  */
882 
883  /**
884  * Opaque object for libavfilter internal use.
885  */
887 
888  /**
889  * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
890  * be used from callbacks like @ref AVFilterGraph.execute.
891  * Libavfilter will not touch this field in any way.
892  */
893  void *opaque;
894 
895  /**
896  * This callback may be set by the caller immediately after allocating the
897  * graph and before adding any filters to it, to provide a custom
898  * multithreading implementation.
899  *
900  * If set, filters with slice threading capability will call this callback
901  * to execute multiple jobs in parallel.
902  *
903  * If this field is left unset, libavfilter will use its internal
904  * implementation, which may or may not be multithreaded depending on the
905  * platform and build options.
906  */
908 
909  char *aresample_swr_opts; ///< swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
910 
911  /**
912  * Private fields
913  *
914  * The following fields are for internal use only.
915  * Their type, offset, number and semantic can change without notice.
916  */
917 
920 
922 } AVFilterGraph;
923 
924 /**
925  * Allocate a filter graph.
926  *
927  * @return the allocated filter graph on success or NULL.
928  */
930 
931 /**
932  * Create a new filter instance in a filter graph.
933  *
934  * @param graph graph in which the new filter will be used
935  * @param filter the filter to create an instance of
936  * @param name Name to give to the new instance (will be copied to
937  * AVFilterContext.name). This may be used by the caller to identify
938  * different filters, libavfilter itself assigns no semantics to
939  * this parameter. May be NULL.
940  *
941  * @return the context of the newly created filter instance (note that it is
942  * also retrievable directly through AVFilterGraph.filters or with
943  * avfilter_graph_get_filter()) on success or NULL on failure.
944  */
946  const AVFilter *filter,
947  const char *name);
948 
949 /**
950  * Get a filter instance identified by instance name from graph.
951  *
952  * @param graph filter graph to search through.
953  * @param name filter instance name (should be unique in the graph).
954  * @return the pointer to the found filter instance or NULL if it
955  * cannot be found.
956  */
958 
959 /**
960  * Create and add a filter instance into an existing graph.
961  * The filter instance is created from the filter filt and inited
962  * with the parameter args. opaque is currently ignored.
963  *
964  * In case of success put in *filt_ctx the pointer to the created
965  * filter instance, otherwise set *filt_ctx to NULL.
966  *
967  * @param name the instance name to give to the created filter instance
968  * @param graph_ctx the filter graph
969  * @return a negative AVERROR error code in case of failure, a non
970  * negative value otherwise
971  */
973  const char *name, const char *args, void *opaque,
974  AVFilterGraph *graph_ctx);
975 
976 /**
977  * Enable or disable automatic format conversion inside the graph.
978  *
979  * Note that format conversion can still happen inside explicitly inserted
980  * scale and aresample filters.
981  *
982  * @param flags any of the AVFILTER_AUTO_CONVERT_* constants
983  */
985 
986 enum {
987  AVFILTER_AUTO_CONVERT_ALL = 0, /**< all automatic conversions enabled */
988  AVFILTER_AUTO_CONVERT_NONE = -1, /**< all automatic conversions disabled */
989 };
990 
991 /**
992  * Check validity and configure all the links and formats in the graph.
993  *
994  * @param graphctx the filter graph
995  * @param log_ctx context used for logging
996  * @return >= 0 in case of success, a negative AVERROR code otherwise
997  */
998 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
999 
1000 /**
1001  * Free a graph, destroy its links, and set *graph to NULL.
1002  * If *graph is NULL, do nothing.
1003  */
1004 void avfilter_graph_free(AVFilterGraph **graph);
1005 
1006 /**
1007  * A linked-list of the inputs/outputs of the filter chain.
1008  *
1009  * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
1010  * where it is used to communicate open (unlinked) inputs and outputs from and
1011  * to the caller.
1012  * This struct specifies, per each not connected pad contained in the graph, the
1013  * filter context and the pad index required for establishing a link.
1014  */
1015 typedef struct AVFilterInOut {
1016  /** unique name for this input/output in the list */
1017  char *name;
1018 
1019  /** filter context associated to this input/output */
1021 
1022  /** index of the filt_ctx pad to use for linking */
1023  int pad_idx;
1024 
1025  /** next input/input in the list, NULL if this is the last */
1027 } AVFilterInOut;
1028 
1029 /**
1030  * Allocate a single AVFilterInOut entry.
1031  * Must be freed with avfilter_inout_free().
1032  * @return allocated AVFilterInOut on success, NULL on failure.
1033  */
1035 
1036 /**
1037  * Free the supplied list of AVFilterInOut and set *inout to NULL.
1038  * If *inout is NULL, do nothing.
1039  */
1040 void avfilter_inout_free(AVFilterInOut **inout);
1041 
1042 /**
1043  * Add a graph described by a string to a graph.
1044  *
1045  * @note The caller must provide the lists of inputs and outputs,
1046  * which therefore must be known before calling the function.
1047  *
1048  * @note The inputs parameter describes inputs of the already existing
1049  * part of the graph; i.e. from the point of view of the newly created
1050  * part, they are outputs. Similarly the outputs parameter describes
1051  * outputs of the already existing filters, which are provided as
1052  * inputs to the parsed filters.
1053  *
1054  * @param graph the filter graph where to link the parsed graph context
1055  * @param filters string to be parsed
1056  * @param inputs linked list to the inputs of the graph
1057  * @param outputs linked list to the outputs of the graph
1058  * @return zero on success, a negative AVERROR code on error
1059  */
1060 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
1062  void *log_ctx);
1063 
1064 /**
1065  * Add a graph described by a string to a graph.
1066  *
1067  * In the graph filters description, if the input label of the first
1068  * filter is not specified, "in" is assumed; if the output label of
1069  * the last filter is not specified, "out" is assumed.
1070  *
1071  * @param graph the filter graph where to link the parsed graph context
1072  * @param filters string to be parsed
1073  * @param inputs pointer to a linked list to the inputs of the graph, may be NULL.
1074  * If non-NULL, *inputs is updated to contain the list of open inputs
1075  * after the parsing, should be freed with avfilter_inout_free().
1076  * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
1077  * If non-NULL, *outputs is updated to contain the list of open outputs
1078  * after the parsing, should be freed with avfilter_inout_free().
1079  * @return non negative on success, a negative AVERROR code on error
1080  */
1081 int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
1083  void *log_ctx);
1084 
1085 /**
1086  * Add a graph described by a string to a graph.
1087  *
1088  * @param[in] graph the filter graph where to link the parsed graph context
1089  * @param[in] filters string to be parsed
1090  * @param[out] inputs a linked list of all free (unlinked) inputs of the
1091  * parsed graph will be returned here. It is to be freed
1092  * by the caller using avfilter_inout_free().
1093  * @param[out] outputs a linked list of all free (unlinked) outputs of the
1094  * parsed graph will be returned here. It is to be freed by the
1095  * caller using avfilter_inout_free().
1096  * @return zero on success, a negative AVERROR code on error
1097  *
1098  * @note This function returns the inputs and outputs that are left
1099  * unlinked after parsing the graph and the caller then deals with
1100  * them.
1101  * @note This function makes no reference whatsoever to already
1102  * existing parts of the graph and the inputs parameter will on return
1103  * contain inputs of the newly parsed part of the graph. Analogously
1104  * the outputs parameter will contain outputs of the newly created
1105  * filters.
1106  */
1107 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
1110 
1111 /**
1112  * Parameters of a filter's input or output pad.
1113  *
1114  * Created as a child of AVFilterParams by avfilter_graph_segment_parse().
1115  * Freed in avfilter_graph_segment_free().
1116  */
1117 typedef struct AVFilterPadParams {
1118  /**
1119  * An av_malloc()'ed string containing the pad label.
1120  *
1121  * May be av_free()'d and set to NULL by the caller, in which case this pad
1122  * will be treated as unlabeled for linking.
1123  * May also be replaced by another av_malloc()'ed string.
1124  */
1125  char *label;
1127 
1128 /**
1129  * Parameters describing a filter to be created in a filtergraph.
1130  *
1131  * Created as a child of AVFilterGraphSegment by avfilter_graph_segment_parse().
1132  * Freed in avfilter_graph_segment_free().
1133  */
1134 typedef struct AVFilterParams {
1135  /**
1136  * The filter context.
1137  *
1138  * Created by avfilter_graph_segment_create_filters() based on
1139  * AVFilterParams.filter_name and instance_name.
1140  *
1141  * Callers may also create the filter context manually, then they should
1142  * av_free() filter_name and set it to NULL. Such AVFilterParams instances
1143  * are then skipped by avfilter_graph_segment_create_filters().
1144  */
1146 
1147  /**
1148  * Name of the AVFilter to be used.
1149  *
1150  * An av_malloc()'ed string, set by avfilter_graph_segment_parse(). Will be
1151  * passed to avfilter_get_by_name() by
1152  * avfilter_graph_segment_create_filters().
1153  *
1154  * Callers may av_free() this string and replace it with another one or
1155  * NULL. If the caller creates the filter instance manually, this string
1156  * MUST be set to NULL.
1157  *
1158  * When both AVFilterParams.filter an AVFilterParams.filter_name are NULL,
1159  * this AVFilterParams instance is skipped by avfilter_graph_segment_*()
1160  * functions.
1161  */
1163  /**
1164  * Name to be used for this filter instance.
1165  *
1166  * An av_malloc()'ed string, may be set by avfilter_graph_segment_parse() or
1167  * left NULL. The caller may av_free() this string and replace with another
1168  * one or NULL.
1169  *
1170  * Will be used by avfilter_graph_segment_create_filters() - passed as the
1171  * third argument to avfilter_graph_alloc_filter(), then freed and set to
1172  * NULL.
1173  */
1175 
1176  /**
1177  * Options to be apllied to the filter.
1178  *
1179  * Filled by avfilter_graph_segment_parse(). Afterwards may be freely
1180  * modified by the caller.
1181  *
1182  * Will be applied to the filter by avfilter_graph_segment_apply_opts()
1183  * with an equivalent of av_opt_set_dict2(filter, &opts, AV_OPT_SEARCH_CHILDREN),
1184  * i.e. any unapplied options will be left in this dictionary.
1185  */
1187 
1189  unsigned nb_inputs;
1190 
1192  unsigned nb_outputs;
1193 } AVFilterParams;
1194 
1195 /**
1196  * A filterchain is a list of filter specifications.
1197  *
1198  * Created as a child of AVFilterGraphSegment by avfilter_graph_segment_parse().
1199  * Freed in avfilter_graph_segment_free().
1200  */
1201 typedef struct AVFilterChain {
1203  size_t nb_filters;
1204 } AVFilterChain;
1205 
1206 /**
1207  * A parsed representation of a filtergraph segment.
1208  *
1209  * A filtergraph segment is conceptually a list of filterchains, with some
1210  * supplementary information (e.g. format conversion flags).
1211  *
1212  * Created by avfilter_graph_segment_parse(). Must be freed with
1213  * avfilter_graph_segment_free().
1214  */
1215 typedef struct AVFilterGraphSegment {
1216  /**
1217  * The filtergraph this segment is associated with.
1218  * Set by avfilter_graph_segment_parse().
1219  */
1221 
1222  /**
1223  * A list of filter chain contained in this segment.
1224  * Set in avfilter_graph_segment_parse().
1225  */
1227  size_t nb_chains;
1228 
1229  /**
1230  * A string containing a colon-separated list of key=value options applied
1231  * to all scale filters in this segment.
1232  *
1233  * May be set by avfilter_graph_segment_parse().
1234  * The caller may free this string with av_free() and replace it with a
1235  * different av_malloc()'ed string.
1236  */
1239 
1240 /**
1241  * Parse a textual filtergraph description into an intermediate form.
1242  *
1243  * This intermediate representation is intended to be modified by the caller as
1244  * described in the documentation of AVFilterGraphSegment and its children, and
1245  * then applied to the graph either manually or with other
1246  * avfilter_graph_segment_*() functions. See the documentation for
1247  * avfilter_graph_segment_apply() for the canonical way to apply
1248  * AVFilterGraphSegment.
1249  *
1250  * @param graph Filter graph the parsed segment is associated with. Will only be
1251  * used for logging and similar auxiliary purposes. The graph will
1252  * not be actually modified by this function - the parsing results
1253  * are instead stored in seg for further processing.
1254  * @param graph_str a string describing the filtergraph segment
1255  * @param flags reserved for future use, caller must set to 0 for now
1256  * @param seg A pointer to the newly-created AVFilterGraphSegment is written
1257  * here on success. The graph segment is owned by the caller and must
1258  * be freed with avfilter_graph_segment_free() before graph itself is
1259  * freed.
1260  *
1261  * @retval "non-negative number" success
1262  * @retval "negative error code" failure
1263  */
1264 int avfilter_graph_segment_parse(AVFilterGraph *graph, const char *graph_str,
1265  int flags, AVFilterGraphSegment **seg);
1266 
1267 /**
1268  * Create filters specified in a graph segment.
1269  *
1270  * Walk through the creation-pending AVFilterParams in the segment and create
1271  * new filter instances for them.
1272  * Creation-pending params are those where AVFilterParams.filter_name is
1273  * non-NULL (and hence AVFilterParams.filter is NULL). All other AVFilterParams
1274  * instances are ignored.
1275  *
1276  * For any filter created by this function, the corresponding
1277  * AVFilterParams.filter is set to the newly-created filter context,
1278  * AVFilterParams.filter_name and AVFilterParams.instance_name are freed and set
1279  * to NULL.
1280  *
1281  * @param seg the filtergraph segment to process
1282  * @param flags reserved for future use, caller must set to 0 for now
1283  *
1284  * @retval "non-negative number" Success, all creation-pending filters were
1285  * successfully created
1286  * @retval AVERROR_FILTER_NOT_FOUND some filter's name did not correspond to a
1287  * known filter
1288  * @retval "another negative error code" other failures
1289  *
1290  * @note Calling this function multiple times is safe, as it is idempotent.
1291  */
1293 
1294 /**
1295  * Apply parsed options to filter instances in a graph segment.
1296  *
1297  * Walk through all filter instances in the graph segment that have option
1298  * dictionaries associated with them and apply those options with
1299  * av_opt_set_dict2(..., AV_OPT_SEARCH_CHILDREN). AVFilterParams.opts is
1300  * replaced by the dictionary output by av_opt_set_dict2(), which should be
1301  * empty (NULL) if all options were successfully applied.
1302  *
1303  * If any options could not be found, this function will continue processing all
1304  * other filters and finally return AVERROR_OPTION_NOT_FOUND (unless another
1305  * error happens). The calling program may then deal with unapplied options as
1306  * it wishes.
1307  *
1308  * Any creation-pending filters (see avfilter_graph_segment_create_filters())
1309  * present in the segment will cause this function to fail. AVFilterParams with
1310  * no associated filter context are simply skipped.
1311  *
1312  * @param seg the filtergraph segment to process
1313  * @param flags reserved for future use, caller must set to 0 for now
1314  *
1315  * @retval "non-negative number" Success, all options were successfully applied.
1316  * @retval AVERROR_OPTION_NOT_FOUND some options were not found in a filter
1317  * @retval "another negative error code" other failures
1318  *
1319  * @note Calling this function multiple times is safe, as it is idempotent.
1320  */
1322 
1323 /**
1324  * Initialize all filter instances in a graph segment.
1325  *
1326  * Walk through all filter instances in the graph segment and call
1327  * avfilter_init_dict(..., NULL) on those that have not been initialized yet.
1328  *
1329  * Any creation-pending filters (see avfilter_graph_segment_create_filters())
1330  * present in the segment will cause this function to fail. AVFilterParams with
1331  * no associated filter context or whose filter context is already initialized,
1332  * are simply skipped.
1333  *
1334  * @param seg the filtergraph segment to process
1335  * @param flags reserved for future use, caller must set to 0 for now
1336  *
1337  * @retval "non-negative number" Success, all filter instances were successfully
1338  * initialized
1339  * @retval "negative error code" failure
1340  *
1341  * @note Calling this function multiple times is safe, as it is idempotent.
1342  */
1344 
1345 /**
1346  * Link filters in a graph segment.
1347  *
1348  * Walk through all filter instances in the graph segment and try to link all
1349  * unlinked input and output pads. Any creation-pending filters (see
1350  * avfilter_graph_segment_create_filters()) present in the segment will cause
1351  * this function to fail. Disabled filters and already linked pads are skipped.
1352  *
1353  * Every filter output pad that has a corresponding AVFilterPadParams with a
1354  * non-NULL label is
1355  * - linked to the input with the matching label, if one exists;
1356  * - exported in the outputs linked list otherwise, with the label preserved.
1357  * Unlabeled outputs are
1358  * - linked to the first unlinked unlabeled input in the next non-disabled
1359  * filter in the chain, if one exists
1360  * - exported in the ouputs linked list otherwise, with NULL label
1361  *
1362  * Similarly, unlinked input pads are exported in the inputs linked list.
1363  *
1364  * @param seg the filtergraph segment to process
1365  * @param flags reserved for future use, caller must set to 0 for now
1366  * @param[out] inputs a linked list of all free (unlinked) inputs of the
1367  * filters in this graph segment will be returned here. It
1368  * is to be freed by the caller using avfilter_inout_free().
1369  * @param[out] outputs a linked list of all free (unlinked) outputs of the
1370  * filters in this graph segment will be returned here. It
1371  * is to be freed by the caller using avfilter_inout_free().
1372  *
1373  * @retval "non-negative number" success
1374  * @retval "negative error code" failure
1375  *
1376  * @note Calling this function multiple times is safe, as it is idempotent.
1377  */
1381 
1382 /**
1383  * Apply all filter/link descriptions from a graph segment to the associated filtergraph.
1384  *
1385  * This functions is currently equivalent to calling the following in sequence:
1386  * - avfilter_graph_segment_create_filters();
1387  * - avfilter_graph_segment_apply_opts();
1388  * - avfilter_graph_segment_init();
1389  * - avfilter_graph_segment_link();
1390  * failing if any of them fails. This list may be extended in the future.
1391  *
1392  * Since the above functions are idempotent, the caller may call some of them
1393  * manually, then do some custom processing on the filtergraph, then call this
1394  * function to do the rest.
1395  *
1396  * @param seg the filtergraph segment to process
1397  * @param flags reserved for future use, caller must set to 0 for now
1398  * @param[out] inputs passed to avfilter_graph_segment_link()
1399  * @param[out] outputs passed to avfilter_graph_segment_link()
1400  *
1401  * @retval "non-negative number" success
1402  * @retval "negative error code" failure
1403  *
1404  * @note Calling this function multiple times is safe, as it is idempotent.
1405  */
1409 
1410 /**
1411  * Free the provided AVFilterGraphSegment and everything associated with it.
1412  *
1413  * @param seg double pointer to the AVFilterGraphSegment to be freed. NULL will
1414  * be written to this pointer on exit from this function.
1415  *
1416  * @note
1417  * The filter contexts (AVFilterParams.filter) are owned by AVFilterGraph rather
1418  * than AVFilterGraphSegment, so they are not freed.
1419  */
1421 
1422 /**
1423  * Send a command to one or more filter instances.
1424  *
1425  * @param graph the filter graph
1426  * @param target the filter(s) to which the command should be sent
1427  * "all" sends to all filters
1428  * otherwise it can be a filter or filter instance name
1429  * which will send the command to all matching filters.
1430  * @param cmd the command to send, for handling simplicity all commands must be alphanumeric only
1431  * @param arg the argument for the command
1432  * @param res a buffer with size res_size where the filter(s) can return a response.
1433  *
1434  * @returns >=0 on success otherwise an error code.
1435  * AVERROR(ENOSYS) on unsupported commands
1436  */
1437 int avfilter_graph_send_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, char *res, int res_len, int flags);
1438 
1439 /**
1440  * Queue a command for one or more filter instances.
1441  *
1442  * @param graph the filter graph
1443  * @param target the filter(s) to which the command should be sent
1444  * "all" sends to all filters
1445  * otherwise it can be a filter or filter instance name
1446  * which will send the command to all matching filters.
1447  * @param cmd the command to sent, for handling simplicity all commands must be alphanumeric only
1448  * @param arg the argument for the command
1449  * @param ts time at which the command should be sent to the filter
1450  *
1451  * @note As this executes commands after this function returns, no return code
1452  * from the filter is provided, also AVFILTER_CMD_FLAG_ONE is not supported.
1453  */
1454 int avfilter_graph_queue_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, int flags, double ts);
1455 
1456 
1457 /**
1458  * Dump a graph into a human-readable string representation.
1459  *
1460  * @param graph the graph to dump
1461  * @param options formatting options; currently ignored
1462  * @return a string, or NULL in case of memory allocation failure;
1463  * the string must be freed using av_free
1464  */
1465 char *avfilter_graph_dump(AVFilterGraph *graph, const char *options);
1466 
1467 /**
1468  * Request a frame on the oldest sink link.
1469  *
1470  * If the request returns AVERROR_EOF, try the next.
1471  *
1472  * Note that this function is not meant to be the sole scheduling mechanism
1473  * of a filtergraph, only a convenience function to help drain a filtergraph
1474  * in a balanced way under normal circumstances.
1475  *
1476  * Also note that AVERROR_EOF does not mean that frames did not arrive on
1477  * some of the sinks during the process.
1478  * When there are multiple sink links, in case the requested link
1479  * returns an EOF, this may cause a filter to flush pending frames
1480  * which are sent to another sink link, although unrequested.
1481  *
1482  * @return the return value of ff_request_frame(),
1483  * or AVERROR_EOF if all links returned AVERROR_EOF
1484  */
1486 
1487 /**
1488  * @}
1489  */
1490 
1491 #endif /* AVFILTER_AVFILTER_H */
func
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:68
AVFilterGraph::execute
avfilter_execute_func * execute
This callback may be set by the caller immediately after allocating the graph and before adding any f...
Definition: avfilter.h:907
AVFilterChannelLayouts
A list of supported channel layouts.
Definition: formats.h:85
AVFilterContext::nb_threads
int nb_threads
Max number of threads allowed in this filter instance.
Definition: avfilter.h:455
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
AVFilterFormatsConfig::samplerates
AVFilterFormats * samplerates
Lists of supported sample rates, only for audio.
Definition: avfilter.h:501
name
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option name
Definition: writing_filters.txt:88
avfilter_filter_pad_count
unsigned avfilter_filter_pad_count(const AVFilter *filter, int is_output)
Get the number of elements in an AVFilter's inputs or outputs array.
Definition: avfilter.c:568
AVFilterGraph::nb_threads
int nb_threads
Maximum number of threads used by filters in this graph.
Definition: avfilter.h:881
avfilter_pad_get_name
const char * avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx)
Get the name of an AVFilterPad.
Definition: avfilter.c:923
AVFilterFormatsConfig::channel_layouts
AVFilterChannelLayouts * channel_layouts
Lists of supported channel layouts, only for audio.
Definition: avfilter.h:506
AVFilterParams::instance_name
char * instance_name
Name to be used for this filter instance.
Definition: avfilter.h:1174
avfilter_graph_segment_create_filters
int avfilter_graph_segment_create_filters(AVFilterGraphSegment *seg, int flags)
Create filters specified in a graph segment.
Definition: graphparser.c:515
AVFilter::pixels_list
enum AVPixelFormat * pixels_list
A pointer to an array of admissible pixel formats delimited by AV_PIX_FMT_NONE.
Definition: avfilter.h:324
AVFilter::priv_class
const AVClass * priv_class
A class for the private data, used to declare filter private AVOptions.
Definition: avfilter.h:200
avfilter_action_func
int() avfilter_action_func(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
A function pointer passed to the AVFilterGraph::execute callback to be executed multiple times,...
Definition: avfilter.h:838
AVFilterContext::var_values
double * var_values
variable values for the enable expression
Definition: avfilter.h:438
AVFilter::pix_fmt
enum AVPixelFormat pix_fmt
Equivalent to { pix_fmt, AV_PIX_FMT_NONE } as pixels_list.
Definition: avfilter.h:339
rational.h
AVFilterContext::is_disabled
int is_disabled
the enabled state from the last expression evaluation
Definition: avfilter.h:439
AVFilter::process_command
int(* process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags)
Make the filter instance process a command.
Definition: avfilter.h:362
AVFilterInOut::next
struct AVFilterInOut * next
next input/input in the list, NULL if this is the last
Definition: avfilter.h:1026
AVFilterContext::nb_outputs
unsigned nb_outputs
number of output pads
Definition: avfilter.h:405
AVFilterContext::av_class
const AVClass * av_class
needed for av_log() and filters common options
Definition: avfilter.h:393
AVFilterGraph::disable_auto_convert
unsigned disable_auto_convert
Definition: avfilter.h:921
AVFilterContext::hw_device_ctx
AVBufferRef * hw_device_ctx
For filters which will create hardware frames, sets the device the filter should create them in.
Definition: avfilter.h:448
AVFilterGraphInternal
Definition: internal.h:132
filter
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce then the filter should push the output frames on the output link immediately As an exception to the previous rule if the input frame is enough to produce several output frames then the filter needs output only at least one per link The additional frames can be left buffered in the filter
Definition: filter_design.txt:228
AVDictionary
Definition: dict.c:32
AVFilterContext::output_pads
AVFilterPad * output_pads
array of output pads
Definition: avfilter.h:403
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:165
AVFilterParams::inputs
AVFilterPadParams ** inputs
Definition: avfilter.h:1188
avfilter_graph_free
void avfilter_graph_free(AVFilterGraph **graph)
Free a graph, destroy its links, and set *graph to NULL.
Definition: avfiltergraph.c:119
AVFilterFormats
A list of supported formats for one end of a filter link.
Definition: formats.h:64
AVFilterParams::outputs
AVFilterPadParams ** outputs
Definition: avfilter.h:1191
avfilter_graph_create_filter
int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt, const char *name, const char *args, void *opaque, AVFilterGraph *graph_ctx)
Create and add a filter instance into an existing graph.
Definition: avfiltergraph.c:138
avfilter_graph_alloc_filter
AVFilterContext * avfilter_graph_alloc_filter(AVFilterGraph *graph, const AVFilter *filter, const char *name)
Create a new filter instance in a filter graph.
Definition: avfiltergraph.c:165
avfilter_graph_segment_link
int avfilter_graph_segment_link(AVFilterGraphSegment *seg, int flags, AVFilterInOut **inputs, AVFilterInOut **outputs)
Link filters in a graph segment.
Definition: graphparser.c:811
AVFilterContext::priv
void * priv
private data for use by the filter
Definition: avfilter.h:407
AVFilterContext::graph
struct AVFilterGraph * graph
filtergraph this filter belongs to
Definition: avfilter.h:409
AVFilterContext::enable_str
char * enable_str
enable expression string
Definition: avfilter.h:436
avfilter_graph_alloc
AVFilterGraph * avfilter_graph_alloc(void)
Allocate a filter graph.
Definition: avfiltergraph.c:82
AVFilter::formats_state
uint8_t formats_state
This field determines the state of the formats union.
Definition: avfilter.h:229
avfilter_insert_filter
int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt, unsigned filt_srcpad_idx, unsigned filt_dstpad_idx)
Insert a filter in the middle of an existing link.
Definition: avfilter.c:246
av_filter_iterate
const AVFilter * av_filter_iterate(void **opaque)
Iterate over all registered filters.
Definition: allfilters.c:600
samplefmt.h
AVFilterContext::extra_hw_frames
int extra_hw_frames
Sets the number of extra hardware frames which the filter will allocate on its output links for use i...
Definition: avfilter.h:478
avfilter_config_links
int avfilter_config_links(AVFilterContext *filter)
Negotiate the media format, dimensions, etc of all inputs to a filter.
Definition: avfilter.c:283
avfilter_graph_segment_free
void avfilter_graph_segment_free(AVFilterGraphSegment **seg)
Free the provided AVFilterGraphSegment and everything associated with it.
Definition: graphparser.c:275
AVFilterGraph::opaque
void * opaque
Opaque user data.
Definition: avfilter.h:893
avfilter_graph_segment_parse
int avfilter_graph_segment_parse(AVFilterGraph *graph, const char *graph_str, int flags, AVFilterGraphSegment **seg)
Parse a textual filtergraph description into an intermediate form.
Definition: graphparser.c:459
AVFilter::flags_internal
int flags_internal
Additional flags for avfilter internal use only.
Definition: avfilter.h:348
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:49
avfilter_license
const char * avfilter_license(void)
Return the libavfilter license.
Definition: version.c:40
AVFilterContext::input_pads
AVFilterPad * input_pads
array of input pads
Definition: avfilter.h:399
avfilter_inout_free
void avfilter_inout_free(AVFilterInOut **inout)
Free the supplied list of AVFilterInOut and set *inout to NULL.
Definition: graphparser.c:75
AVFILTER_AUTO_CONVERT_ALL
@ AVFILTER_AUTO_CONVERT_ALL
all automatic conversions enabled
Definition: avfilter.h:987
AVFilterChain::filters
AVFilterParams ** filters
Definition: avfilter.h:1202
AVFilter::samples_list
enum AVSampleFormat * samples_list
Analogous to pixels, but delimited by AV_SAMPLE_FMT_NONE and restricted to filters that only have AVM...
Definition: avfilter.h:335
avfilter_process_command
int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags)
Make the filter instance process a command.
Definition: avfilter.c:547
filters
#define filters(fmt, type, inverse, clp, inverset, clip, one, clip_fn, packed)
Definition: af_crystalizer.c:55
outputs
static const AVFilterPad outputs[]
Definition: af_acontrast.c:172
avfilter_graph_segment_init
int avfilter_graph_segment_init(AVFilterGraphSegment *seg, int flags)
Initialize all filter instances in a graph segment.
Definition: graphparser.c:614
AVFilter::flags
int flags
A combination of AVFILTER_FLAG_*.
Definition: avfilter.h:205
ctx
AVFormatContext * ctx
Definition: movenc.c:48
AVFilterGraph::aresample_swr_opts
char * aresample_swr_opts
swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
Definition: avfilter.h:909
AVFilterPadParams::label
char * label
An av_malloc()'ed string containing the pad label.
Definition: avfilter.h:1125
link
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a link
Definition: filter_design.txt:23
AVFilter::formats
union AVFilter::@217 formats
The state of the following union is determined by formats_state.
arg
const char * arg
Definition: jacosubdec.c:67
AVFilter::activate
int(* activate)(AVFilterContext *ctx)
Filter activation function.
Definition: avfilter.h:376
avfilter_get_by_name
const AVFilter * avfilter_get_by_name(const char *name)
Get a filter definition matching the given name.
Definition: allfilters.c:611
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
AVFilterContext::thread_type
int thread_type
Type of multithreading being allowed/used.
Definition: avfilter.h:427
avfilter_graph_config
int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx)
Check validity and configure all the links and formats in the graph.
Definition: avfiltergraph.c:1167
avfilter_graph_segment_apply
int avfilter_graph_segment_apply(AVFilterGraphSegment *seg, int flags, AVFilterInOut **inputs, AVFilterInOut **outputs)
Apply all filter/link descriptions from a graph segment to the associated filtergraph.
Definition: graphparser.c:853
AVFilterParams
Parameters describing a filter to be created in a filtergraph.
Definition: avfilter.h:1134
AVFilter::outputs
const AVFilterPad * outputs
List of static outputs.
Definition: avfilter.h:190
avfilter_graph_set_auto_convert
void avfilter_graph_set_auto_convert(AVFilterGraph *graph, unsigned flags)
Enable or disable automatic format conversion inside the graph.
Definition: avfiltergraph.c:160
AVFilterParams::filter
AVFilterContext * filter
The filter context.
Definition: avfilter.h:1145
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
AVFilterChain::nb_filters
size_t nb_filters
Definition: avfilter.h:1203
AVFilterParams::filter_name
char * filter_name
Name of the AVFilter to be used.
Definition: avfilter.h:1162
AVFilterGraph::filters
AVFilterContext ** filters
Definition: avfilter.h:857
AVFilterContext::inputs
AVFilterLink ** inputs
array of pointers to input links
Definition: avfilter.h:400
AVFilterInternal
Definition: internal.h:138
AVFilterContext::name
char * name
name of this filter instance
Definition: avfilter.h:397
avfilter_inout_alloc
AVFilterInOut * avfilter_inout_alloc(void)
Allocate a single AVFilterInOut entry.
Definition: graphparser.c:70
avfilter_graph_get_filter
AVFilterContext * avfilter_graph_get_filter(AVFilterGraph *graph, const char *name)
Get a filter instance identified by instance name from graph.
Definition: avfiltergraph.c:283
avfilter_graph_request_oldest
int avfilter_graph_request_oldest(AVFilterGraph *graph)
Request a frame on the oldest sink link.
Definition: avfiltergraph.c:1295
AVFilterGraphSegment::chains
AVFilterChain ** chains
A list of filter chain contained in this segment.
Definition: avfilter.h:1226
AVFilterGraph
Definition: avfilter.h:855
inputs
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
Definition: filter_design.txt:243
avfilter_graph_parse2
int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters, AVFilterInOut **inputs, AVFilterInOut **outputs)
Add a graph described by a string to a graph.
Definition: graphparser.c:137
AVFilterParams::nb_outputs
unsigned nb_outputs
Definition: avfilter.h:1192
AVFilterFormatsConfig
Lists of formats / etc.
Definition: avfilter.h:491
AVFilterGraphSegment
A parsed representation of a filtergraph segment.
Definition: avfilter.h:1215
AVFilterInOut::pad_idx
int pad_idx
index of the filt_ctx pad to use for linking
Definition: avfilter.h:1023
FFFrameQueue
Queue of AVFrame pointers.
Definition: framequeue.h:53
AVFilterGraph::scale_sws_opts
char * scale_sws_opts
sws options to use for the auto-inserted scale filters
Definition: avfilter.h:860
options
const OptionDef options[]
AVFilterContext::nb_inputs
unsigned nb_inputs
number of input pads
Definition: avfilter.h:401
AVFilterGraph::av_class
const AVClass * av_class
Definition: avfilter.h:856
AVMediaType
AVMediaType
Definition: avutil.h:199
AVFilterContext::command_queue
struct AVFilterCommand * command_queue
Definition: avfilter.h:434
AVChannelLayout
An AVChannelLayout holds information about the channel layout of audio data.
Definition: channel_layout.h:301
AVFilterInOut::filter_ctx
AVFilterContext * filter_ctx
filter context associated to this input/output
Definition: avfilter.h:1020
avfilter_execute_func
int() avfilter_execute_func(AVFilterContext *ctx, avfilter_action_func *func, void *arg, int *ret, int nb_jobs)
A function executing multiple jobs, possibly in parallel.
Definition: avfilter.h:852
AVFilter::preinit
int(* preinit)(AVFilterContext *ctx)
Filter pre-initialization function.
Definition: avfilter.h:244
avfilter_link
int avfilter_link(AVFilterContext *src, unsigned srcpad, AVFilterContext *dst, unsigned dstpad)
Link two filters together.
Definition: avfilter.c:148
avfilter_graph_queue_command
int avfilter_graph_queue_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, int flags, double ts)
Queue a command for one or more filter instances.
Definition: avfiltergraph.c:1215
AVFilterGraphSegment::scale_sws_opts
char * scale_sws_opts
A string containing a colon-separated list of key=value options applied to all scale filters in this ...
Definition: avfilter.h:1237
frame.h
AVFilter::description
const char * description
A description of the filter.
Definition: avfilter.h:172
avfilter_link_free
void avfilter_link_free(AVFilterLink **link)
Free the link in *link, and set its pointer to NULL.
Definition: avfilter.c:192
buffer.h
attribute_deprecated
#define attribute_deprecated
Definition: attributes.h:104
attributes.h
AVFilter::nb_inputs
uint8_t nb_inputs
The number of entries in the list of inputs.
Definition: avfilter.h:218
AVFilter::init
int(* init)(AVFilterContext *ctx)
Filter initialization function.
Definition: avfilter.h:267
avfilter_init_str
int avfilter_init_str(AVFilterContext *ctx, const char *args)
Initialize a filter with the supplied parameters.
Definition: avfilter.c:895
AVFilterParams::nb_inputs
unsigned nb_inputs
Definition: avfilter.h:1189
AVFilter::query_func
int(* query_func)(AVFilterContext *)
Query formats supported by the filter on its inputs and outputs.
Definition: avfilter.h:313
log.h
AVFilterGraphSegment::graph
AVFilterGraph * graph
The filtergraph this segment is associated with.
Definition: avfilter.h:1220
avfilter_graph_parse_ptr
int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters, AVFilterInOut **inputs, AVFilterInOut **outputs, void *log_ctx)
Add a graph described by a string to a graph.
Definition: graphparser.c:889
AVFilterCommand
Definition: internal.h:33
version_major.h
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:55
AVFilterGraph::thread_type
int thread_type
Type of multithreading allowed for filters in this graph.
Definition: avfilter.h:874
filt
static const int8_t filt[NUMTAPS *2]
Definition: af_earwax.c:39
AVFilter::priv_size
int priv_size
size of private data to allocate for the filter
Definition: avfilter.h:346
AVFilter
Filter definition.
Definition: avfilter.h:161
ret
ret
Definition: filter_design.txt:187
AVFilterGraph::sink_links
AVFilterLink ** sink_links
Private fields.
Definition: avfilter.h:918
pixfmt.h
avfilter_configuration
const char * avfilter_configuration(void)
Return the libavfilter build-time configuration.
Definition: version.c:35
AVFilterParams::opts
AVDictionary * opts
Options to be apllied to the filter.
Definition: avfilter.h:1186
avfilter_graph_dump
char * avfilter_graph_dump(AVFilterGraph *graph, const char *options)
Dump a graph into a human-readable string representation.
Definition: graphdump.c:157
dict.h
AVFilter::nb_outputs
uint8_t nb_outputs
The number of entries in the list of outputs.
Definition: avfilter.h:223
avfilter_pad_get_type
enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx)
Get the type of an AVFilterPad.
Definition: avfilter.c:928
avfilter_init_dict
int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options)
Initialize a filter with the supplied dictionary of options.
Definition: avfilter.c:855
AVFilterChain
A filterchain is a list of filter specifications.
Definition: avfilter.h:1201
version.h
AVFilterContext::enable
void * enable
parsed expression (AVExpr*)
Definition: avfilter.h:437
AVFilterGraphSegment::nb_chains
size_t nb_chains
Definition: avfilter.h:1227
AVFilterContext
An instance of a filter.
Definition: avfilter.h:392
avfilter_graph_parse
int avfilter_graph_parse(AVFilterGraph *graph, const char *filters, AVFilterInOut *inputs, AVFilterInOut *outputs, void *log_ctx)
Add a graph described by a string to a graph.
Definition: graphparser.c:163
avutil.h
AVBufferRef
A reference to a data buffer.
Definition: buffer.h:82
AVFilterFormatsConfig::formats
AVFilterFormats * formats
List of supported formats (pixel or sample).
Definition: avfilter.h:496
AVFilter::inputs
const AVFilterPad * inputs
List of static inputs.
Definition: avfilter.h:181
AVFilter::uninit
void(* uninit)(AVFilterContext *ctx)
Filter uninitialization function.
Definition: avfilter.h:279
avfilter_free
void avfilter_free(AVFilterContext *filter)
Free a filter context.
Definition: avfilter.c:731
AVFilter::sample_fmt
enum AVSampleFormat sample_fmt
Equivalent to { sample_fmt, AV_SAMPLE_FMT_NONE } as samples_list.
Definition: avfilter.h:343
status_in
the definition of that something depends on the semantic of the filter The callback must examine the status of the filter s links and proceed accordingly The status of output links is stored in the status_in and status_out fields and tested by the then the processing requires a frame on this link and the filter is expected to make efforts in that direction The status of input links is stored by the status_in
Definition: filter_design.txt:154
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
AVFilterInOut::name
char * name
unique name for this input/output in the list
Definition: avfilter.h:1017
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
avfilter_graph_send_command
int avfilter_graph_send_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, char *res, int res_len, int flags)
Send a command to one or more filter instances.
Definition: avfiltergraph.c:1185
avfilter_graph_segment_apply_opts
int avfilter_graph_segment_apply_opts(AVFilterGraphSegment *seg, int flags)
Apply parsed options to filter instances in a graph segment.
Definition: graphparser.c:584
AVFILTER_AUTO_CONVERT_NONE
@ AVFILTER_AUTO_CONVERT_NONE
all automatic conversions disabled
Definition: avfilter.h:988
AVFilterGraph::nb_filters
unsigned nb_filters
Definition: avfilter.h:858
AVFilterContext::filter
const AVFilter * filter
the AVFilter of which this is an instance
Definition: avfilter.h:395
int
int
Definition: ffmpeg_filter.c:156
avfilter_version
unsigned avfilter_version(void)
Return the LIBAVFILTER_VERSION_INT constant.
Definition: version.c:29
avfilter_get_class
const AVClass * avfilter_get_class(void)
Definition: avfilter.c:1517
AVFilterInOut
A linked-list of the inputs/outputs of the filter chain.
Definition: avfilter.h:1015
AVFilterGraph::sink_links_count
int sink_links_count
Definition: avfilter.h:919
AVFilterContext::ready
unsigned ready
Ready status of the filter.
Definition: avfilter.h:462
AVFilterPadParams
Parameters of a filter's input or output pad.
Definition: avfilter.h:1117
AVFilterContext::outputs
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:404