3 * Copyright (c) 2007 Bobby Bingham
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #ifndef AVFILTER_AVFILTER_H
23 #define AVFILTER_AVFILTER_H
28 * Main libavfilter public API header
32 * @defgroup lavfi libavfilter
33 * Graph-based frame editing library.
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"
50 #include "libavfilter/version.h"
53 * Return the LIBAVFILTER_VERSION_INT constant.
55 unsigned avfilter_version(void);
58 * Return the libavfilter build-time configuration.
60 const char *avfilter_configuration(void);
63 * Return the libavfilter license.
65 const char *avfilter_license(void);
67 typedef struct AVFilterContext AVFilterContext;
68 typedef struct AVFilterLink AVFilterLink;
69 typedef struct AVFilterPad AVFilterPad;
70 typedef struct AVFilterFormats AVFilterFormats;
73 * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
74 * AVFilter.inputs/outputs).
76 int avfilter_pad_count(const AVFilterPad *pads);
79 * Get the name of an AVFilterPad.
81 * @param pads an array of AVFilterPads
82 * @param pad_idx index of the pad in the array it; is the caller's
83 * responsibility to ensure the index is valid
85 * @return name of the pad_idx'th pad in pads
87 const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
90 * Get the type of an AVFilterPad.
92 * @param pads an array of AVFilterPads
93 * @param pad_idx index of the pad in the array; it is the caller's
94 * responsibility to ensure the index is valid
96 * @return type of the pad_idx'th pad in pads
98 enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
101 * The number of the filter inputs is not determined just by AVFilter.inputs.
102 * The filter might add additional inputs during initialization depending on the
103 * options supplied to it.
105 #define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
107 * The number of the filter outputs is not determined just by AVFilter.outputs.
108 * The filter might add additional outputs during initialization depending on
109 * the options supplied to it.
111 #define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
113 * The filter supports multithreading by splitting frames into multiple parts
114 * and processing them concurrently.
116 #define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
118 * Some filters support a generic "enable" expression option that can be used
119 * to enable or disable a filter in the timeline. Filters supporting this
120 * option have this flag set. When the enable expression is false, the default
121 * no-op filter_frame() function is called in place of the filter_frame()
122 * callback defined on each input pad, thus the frame is passed unchanged to
125 #define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC (1 << 16)
127 * Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will
128 * have its filter_frame() callback(s) called as usual even when the enable
129 * expression is false. The filter will disable filtering within the
130 * filter_frame() callback(s) itself, for example executing code depending on
131 * the AVFilterContext->is_disabled value.
133 #define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL (1 << 17)
135 * Handy mask to test whether the filter supports or no the timeline feature
136 * (internally or generically).
138 #define AVFILTER_FLAG_SUPPORT_TIMELINE (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
141 * Filter definition. This defines the pads a filter contains, and all the
142 * callback functions used to interact with the filter.
144 typedef struct AVFilter {
146 * Filter name. Must be non-NULL and unique among filters.
151 * A description of the filter. May be NULL.
153 * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
155 const char *description;
158 * List of inputs, terminated by a zeroed element.
160 * NULL if there are no (static) inputs. Instances of filters with
161 * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
164 const AVFilterPad *inputs;
166 * List of outputs, terminated by a zeroed element.
168 * NULL if there are no (static) outputs. Instances of filters with
169 * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
172 const AVFilterPad *outputs;
175 * A class for the private data, used to declare filter private AVOptions.
176 * This field is NULL for filters that do not declare any options.
178 * If this field is non-NULL, the first member of the filter private data
179 * must be a pointer to AVClass, which will be set by libavfilter generic
180 * code to this class.
182 const AVClass *priv_class;
185 * A combination of AVFILTER_FLAG_*
189 /*****************************************************************
190 * All fields below this line are not part of the public API. They
191 * may not be used outside of libavfilter and can be changed and
193 * New public fields should be added right above.
194 *****************************************************************
198 * Filter pre-initialization function
200 * This callback will be called immediately after the filter context is
201 * allocated, to allow allocating and initing sub-objects.
203 * If this callback is not NULL, the uninit callback will be called on
204 * allocation failure.
206 * @return 0 on success,
207 * AVERROR code on failure (but the code will be
208 * dropped and treated as ENOMEM by the calling code)
210 int (*preinit)(AVFilterContext *ctx);
213 * Filter initialization function.
215 * This callback will be called only once during the filter lifetime, after
216 * all the options have been set, but before links between filters are
217 * established and format negotiation is done.
219 * Basic filter initialization should be done here. Filters with dynamic
220 * inputs and/or outputs should create those inputs/outputs here based on
221 * provided options. No more changes to this filter's inputs/outputs can be
222 * done after this callback.
224 * This callback must not assume that the filter links exist or frame
225 * parameters are known.
227 * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
228 * initialization fails, so this callback does not have to clean up on
231 * @return 0 on success, a negative AVERROR on failure
233 int (*init)(AVFilterContext *ctx);
236 * Should be set instead of @ref AVFilter.init "init" by the filters that
237 * want to pass a dictionary of AVOptions to nested contexts that are
238 * allocated during init.
240 * On return, the options dict should be freed and replaced with one that
241 * contains all the options which could not be processed by this filter (or
242 * with NULL if all the options were processed).
244 * Otherwise the semantics is the same as for @ref AVFilter.init "init".
246 int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
249 * Filter uninitialization function.
251 * Called only once right before the filter is freed. Should deallocate any
252 * memory held by the filter, release any buffer references, etc. It does
253 * not need to deallocate the AVFilterContext.priv memory itself.
255 * This callback may be called even if @ref AVFilter.init "init" was not
256 * called or failed, so it must be prepared to handle such a situation.
258 void (*uninit)(AVFilterContext *ctx);
261 * Query formats supported by the filter on its inputs and outputs.
263 * This callback is called after the filter is initialized (so the inputs
264 * and outputs are fixed), shortly before the format negotiation. This
265 * callback may be called more than once.
267 * This callback must set AVFilterLink.out_formats on every input link and
268 * AVFilterLink.in_formats on every output link to a list of pixel/sample
269 * formats that the filter supports on that link. For audio links, this
270 * filter must also set @ref AVFilterLink.in_samplerates "in_samplerates" /
271 * @ref AVFilterLink.out_samplerates "out_samplerates" and
272 * @ref AVFilterLink.in_channel_layouts "in_channel_layouts" /
273 * @ref AVFilterLink.out_channel_layouts "out_channel_layouts" analogously.
275 * This callback may be NULL for filters with one input, in which case
276 * libavfilter assumes that it supports all input formats and preserves
279 * @return zero on success, a negative value corresponding to an
280 * AVERROR code otherwise
282 int (*query_formats)(AVFilterContext *);
284 int priv_size; ///< size of private data to allocate for the filter
286 int flags_internal; ///< Additional flags for avfilter internal use only.
289 * Used by the filter registration system. Must not be touched by any other
292 struct AVFilter *next;
295 * Make the filter instance process a command.
297 * @param cmd the command to process, for handling simplicity all commands must be alphanumeric only
298 * @param arg the argument for the command
299 * @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.
300 * @param flags if AVFILTER_CMD_FLAG_FAST is set and the command would be
301 * time consuming then a filter should treat it like an unsupported command
303 * @returns >=0 on success otherwise an error code.
304 * AVERROR(ENOSYS) on unsupported commands
306 int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);
309 * Filter initialization function, alternative to the init()
310 * callback. Args contains the user-supplied parameters, opaque is
311 * used for providing binary data.
313 int (*init_opaque)(AVFilterContext *ctx, void *opaque);
316 * Filter activation function.
318 * Called when any processing is needed from the filter, instead of any
319 * filter_frame and request_frame on pads.
321 * The function must examine inlinks and outlinks and perform a single
322 * step of processing. If there is nothing to do, the function must do
323 * nothing and not return an error. If more steps are or may be
324 * possible, it must use ff_filter_set_ready() to schedule another
327 int (*activate)(AVFilterContext *ctx);
331 * Process multiple parts of the frame concurrently.
333 #define AVFILTER_THREAD_SLICE (1 << 0)
335 typedef struct AVFilterInternal AVFilterInternal;
337 /** An instance of a filter */
338 struct AVFilterContext {
339 const AVClass *av_class; ///< needed for av_log() and filters common options
341 const AVFilter *filter; ///< the AVFilter of which this is an instance
343 char *name; ///< name of this filter instance
345 AVFilterPad *input_pads; ///< array of input pads
346 AVFilterLink **inputs; ///< array of pointers to input links
347 unsigned nb_inputs; ///< number of input pads
349 AVFilterPad *output_pads; ///< array of output pads
350 AVFilterLink **outputs; ///< array of pointers to output links
351 unsigned nb_outputs; ///< number of output pads
353 void *priv; ///< private data for use by the filter
355 struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
358 * Type of multithreading being allowed/used. A combination of
359 * AVFILTER_THREAD_* flags.
361 * May be set by the caller before initializing the filter to forbid some
362 * or all kinds of multithreading for this filter. The default is allowing
365 * When the filter is initialized, this field is combined using bit AND with
366 * AVFilterGraph.thread_type to get the final mask used for determining
367 * allowed threading types. I.e. a threading type needs to be set in both
370 * After the filter is initialized, libavfilter sets this field to the
371 * threading type that is actually used (0 for no multithreading).
376 * An opaque struct for libavfilter internal use.
378 AVFilterInternal *internal;
380 struct AVFilterCommand *command_queue;
382 char *enable_str; ///< enable expression string
383 void *enable; ///< parsed expression (AVExpr*)
384 double *var_values; ///< variable values for the enable expression
385 int is_disabled; ///< the enabled state from the last expression evaluation
388 * For filters which will create hardware frames, sets the device the
389 * filter should create them in. All other filters will ignore this field:
390 * in particular, a filter which consumes or processes hardware frames will
391 * instead use the hw_frames_ctx field in AVFilterLink to carry the
392 * hardware context information.
394 AVBufferRef *hw_device_ctx;
397 * Max number of threads allowed in this filter instance.
398 * If <= 0, its value is ignored.
399 * Overrides global number of threads set per filter graph.
404 * Ready status of the filter.
405 * A non-0 value means that the filter needs activating;
406 * a higher value suggests a more urgent activation.
412 * A link between two filters. This contains pointers to the source and
413 * destination filters between which this link exists, and the indexes of
414 * the pads involved. In addition, this link also contains the parameters
415 * which have been negotiated and agreed upon between the filter, such as
416 * image dimensions, format, etc.
418 * Applications must not normally access the link structure directly.
419 * Use the buffersrc and buffersink API instead.
420 * In the future, access to the header may be reserved for filters
423 struct AVFilterLink {
424 AVFilterContext *src; ///< source filter
425 AVFilterPad *srcpad; ///< output pad on the source filter
427 AVFilterContext *dst; ///< dest filter
428 AVFilterPad *dstpad; ///< input pad on the dest filter
430 enum AVMediaType type; ///< filter media type
432 /* These parameters apply only to video */
433 int w; ///< agreed upon image width
434 int h; ///< agreed upon image height
435 AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
436 /* These parameters apply only to audio */
437 uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
438 int sample_rate; ///< samples per second
440 int format; ///< agreed upon media format
443 * Define the time base used by the PTS of the frames/samples
444 * which will pass through this link.
445 * During the configuration stage, each filter is supposed to
446 * change only the output timebase, while the timebase of the
447 * input link is assumed to be an unchangeable property.
449 AVRational time_base;
451 /*****************************************************************
452 * All fields below this line are not part of the public API. They
453 * may not be used outside of libavfilter and can be changed and
455 * New public fields should be added right above.
456 *****************************************************************
459 * Lists of formats and channel layouts supported by the input and output
460 * filters respectively. These lists are used for negotiating the format
461 * to actually be used, which will be loaded into the format and
462 * channel_layout members, above, when chosen.
465 AVFilterFormats *in_formats;
466 AVFilterFormats *out_formats;
469 * Lists of channel layouts and sample rates used for automatic
472 AVFilterFormats *in_samplerates;
473 AVFilterFormats *out_samplerates;
474 struct AVFilterChannelLayouts *in_channel_layouts;
475 struct AVFilterChannelLayouts *out_channel_layouts;
478 * Audio only, the destination filter sets this to a non-zero value to
479 * request that buffers with the given number of samples should be sent to
480 * it. AVFilterPad.needs_fifo must also be set on the corresponding input
482 * Last buffer before EOF will be padded with silence.
486 /** stage of the initialization of the link properties (dimensions, etc) */
488 AVLINK_UNINIT = 0, ///< not started
489 AVLINK_STARTINIT, ///< started, but incomplete
490 AVLINK_INIT ///< complete
494 * Graph the filter belongs to.
496 struct AVFilterGraph *graph;
499 * Current timestamp of the link, as defined by the most recent
500 * frame(s), in link time_base units.
505 * Current timestamp of the link, as defined by the most recent
506 * frame(s), in AV_TIME_BASE units.
508 int64_t current_pts_us;
511 * Index in the age array.
516 * Frame rate of the stream on the link, or 1/0 if unknown or variable;
517 * if left to 0/0, will be automatically copied from the first input
518 * of the source filter if it exists.
520 * Sources should set it to the best estimation of the real frame rate.
521 * If the source frame rate is unknown or variable, set this to 1/0.
522 * Filters should update it if necessary depending on their function.
523 * Sinks can use it to set a default output frame rate.
524 * It is similar to the r_frame_rate field in AVStream.
526 AVRational frame_rate;
529 * Buffer partially filled with samples to achieve a fixed/minimum size.
531 AVFrame *partial_buf;
534 * Size of the partial buffer to allocate.
535 * Must be between min_samples and max_samples.
537 int partial_buf_size;
540 * Minimum number of samples to filter at once. If filter_frame() is
541 * called with fewer samples, it will accumulate them in partial_buf.
542 * This field and the related ones must not be changed after filtering
544 * If 0, all related fields are ignored.
549 * Maximum number of samples to filter at once. If filter_frame() is
550 * called with more samples, it will split them.
555 * Number of channels.
560 * Link processing flags.
565 * Number of past frames sent through the link.
567 int64_t frame_count_in, frame_count_out;
570 * A pointer to a FFFramePool struct.
575 * True if a frame is currently wanted on the output of this filter.
576 * Set when ff_request_frame() is called by the output,
577 * cleared when a frame is filtered.
579 int frame_wanted_out;
582 * For hwaccel pixel formats, this should be a reference to the
583 * AVHWFramesContext describing the frames.
585 AVBufferRef *hw_frames_ctx;
587 #ifndef FF_INTERNAL_FIELDS
590 * Internal structure members.
591 * The fields below this limit are internal for libavfilter's use
592 * and must in no way be accessed by applications.
594 char reserved[0xF000];
596 #else /* FF_INTERNAL_FIELDS */
599 * Queue of frames waiting to be filtered.
604 * If set, the source filter can not generate a frame as is.
605 * The goal is to avoid repeatedly calling the request_frame() method on
608 int frame_blocked_in;
612 * If not zero, all attempts of filter_frame will fail with the
613 * corresponding code.
618 * Timestamp of the input status change.
620 int64_t status_in_pts;
623 * Link output status.
624 * If not zero, all attempts of request_frame will fail with the
625 * corresponding code.
629 #endif /* FF_INTERNAL_FIELDS */
634 * Link two filters together.
636 * @param src the source filter
637 * @param srcpad index of the output pad on the source filter
638 * @param dst the destination filter
639 * @param dstpad index of the input pad on the destination filter
640 * @return zero on success
642 int avfilter_link(AVFilterContext *src, unsigned srcpad,
643 AVFilterContext *dst, unsigned dstpad);
646 * Free the link in *link, and set its pointer to NULL.
648 void avfilter_link_free(AVFilterLink **link);
651 * Get the number of channels of a link.
653 int avfilter_link_get_channels(AVFilterLink *link);
656 * Set the closed field of a link.
657 * @deprecated applications are not supposed to mess with links, they should
661 void avfilter_link_set_closed(AVFilterLink *link, int closed);
664 * Negotiate the media format, dimensions, etc of all inputs to a filter.
666 * @param filter the filter to negotiate the properties for its inputs
667 * @return zero on successful negotiation
669 int avfilter_config_links(AVFilterContext *filter);
671 #define AVFILTER_CMD_FLAG_ONE 1 ///< Stop once a filter understood the command (for target=all for example), fast filters are favored automatically
672 #define AVFILTER_CMD_FLAG_FAST 2 ///< Only execute command when its fast (like a video out that supports contrast adjustment in hw)
675 * Make the filter instance process a command.
676 * It is recommended to use avfilter_graph_send_command().
678 int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
680 /** Initialize the filter system. Register all builtin filters. */
681 void avfilter_register_all(void);
684 * Register a filter. This is only needed if you plan to use
685 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
686 * filter can still by instantiated with avfilter_graph_alloc_filter even if it
689 * @param filter the filter to register
690 * @return 0 if the registration was successful, a negative value
693 int avfilter_register(AVFilter *filter);
696 * Get a filter definition matching the given name.
698 * @param name the filter name to find
699 * @return the filter definition, if any matching one is registered.
700 * NULL if none found.
702 const AVFilter *avfilter_get_by_name(const char *name);
705 * Iterate over all registered filters.
706 * @return If prev is non-NULL, next registered filter after prev or NULL if
707 * prev is the last filter. If prev is NULL, return the first registered filter.
709 const AVFilter *avfilter_next(const AVFilter *prev);
712 * Initialize a filter with the supplied parameters.
714 * @param ctx uninitialized filter context to initialize
715 * @param args Options to initialize the filter with. This must be a
716 * ':'-separated list of options in the 'key=value' form.
717 * May be NULL if the options have been set directly using the
718 * AVOptions API or there are no options that need to be set.
719 * @return 0 on success, a negative AVERROR on failure
721 int avfilter_init_str(AVFilterContext *ctx, const char *args);
724 * Initialize a filter with the supplied dictionary of options.
726 * @param ctx uninitialized filter context to initialize
727 * @param options An AVDictionary filled with options for this filter. On
728 * return this parameter will be destroyed and replaced with
729 * a dict containing options that were not found. This dictionary
730 * must be freed by the caller.
731 * May be NULL, then this function is equivalent to
732 * avfilter_init_str() with the second parameter set to NULL.
733 * @return 0 on success, a negative AVERROR on failure
735 * @note This function and avfilter_init_str() do essentially the same thing,
736 * the difference is in manner in which the options are passed. It is up to the
737 * calling code to choose whichever is more preferable. The two functions also
738 * behave differently when some of the provided options are not declared as
739 * supported by the filter. In such a case, avfilter_init_str() will fail, but
740 * this function will leave those extra options in the options AVDictionary and
743 int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
746 * Free a filter context. This will also remove the filter from its
747 * filtergraph's list of filters.
749 * @param filter the filter to free
751 void avfilter_free(AVFilterContext *filter);
754 * Insert a filter in the middle of an existing link.
756 * @param link the link into which the filter should be inserted
757 * @param filt the filter to be inserted
758 * @param filt_srcpad_idx the input pad on the filter to connect
759 * @param filt_dstpad_idx the output pad on the filter to connect
760 * @return zero on success
762 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
763 unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
766 * @return AVClass for AVFilterContext.
768 * @see av_opt_find().
770 const AVClass *avfilter_get_class(void);
772 typedef struct AVFilterGraphInternal AVFilterGraphInternal;
775 * A function pointer passed to the @ref AVFilterGraph.execute callback to be
776 * executed multiple times, possibly in parallel.
778 * @param ctx the filter context the job belongs to
779 * @param arg an opaque parameter passed through from @ref
780 * AVFilterGraph.execute
781 * @param jobnr the index of the job being executed
782 * @param nb_jobs the total number of jobs
784 * @return 0 on success, a negative AVERROR on error
786 typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
789 * A function executing multiple jobs, possibly in parallel.
791 * @param ctx the filter context to which the jobs belong
792 * @param func the function to be called multiple times
793 * @param arg the argument to be passed to func
794 * @param ret a nb_jobs-sized array to be filled with return values from each
796 * @param nb_jobs the number of jobs to execute
798 * @return 0 on success, a negative AVERROR on error
800 typedef int (avfilter_execute_func)(AVFilterContext *ctx, avfilter_action_func *func,
801 void *arg, int *ret, int nb_jobs);
803 typedef struct AVFilterGraph {
804 const AVClass *av_class;
805 AVFilterContext **filters;
808 char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
810 attribute_deprecated char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
814 * Type of multithreading allowed for filters in this graph. A combination
815 * of AVFILTER_THREAD_* flags.
817 * May be set by the caller at any point, the setting will apply to all
818 * filters initialized after that. The default is allowing everything.
820 * When a filter in this graph is initialized, this field is combined using
821 * bit AND with AVFilterContext.thread_type to get the final mask used for
822 * determining allowed threading types. I.e. a threading type needs to be
823 * set in both to be allowed.
828 * Maximum number of threads used by filters in this graph. May be set by
829 * the caller before adding any filters to the filtergraph. Zero (the
830 * default) means that the number of threads is determined automatically.
835 * Opaque object for libavfilter internal use.
837 AVFilterGraphInternal *internal;
840 * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
841 * be used from callbacks like @ref AVFilterGraph.execute.
842 * Libavfilter will not touch this field in any way.
847 * This callback may be set by the caller immediately after allocating the
848 * graph and before adding any filters to it, to provide a custom
849 * multithreading implementation.
851 * If set, filters with slice threading capability will call this callback
852 * to execute multiple jobs in parallel.
854 * If this field is left unset, libavfilter will use its internal
855 * implementation, which may or may not be multithreaded depending on the
856 * platform and build options.
858 avfilter_execute_func *execute;
860 char *aresample_swr_opts; ///< swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
865 * The following fields are for internal use only.
866 * Their type, offset, number and semantic can change without notice.
869 AVFilterLink **sink_links;
870 int sink_links_count;
872 unsigned disable_auto_convert;
876 * Allocate a filter graph.
878 * @return the allocated filter graph on success or NULL.
880 AVFilterGraph *avfilter_graph_alloc(void);
883 * Create a new filter instance in a filter graph.
885 * @param graph graph in which the new filter will be used
886 * @param filter the filter to create an instance of
887 * @param name Name to give to the new instance (will be copied to
888 * AVFilterContext.name). This may be used by the caller to identify
889 * different filters, libavfilter itself assigns no semantics to
890 * this parameter. May be NULL.
892 * @return the context of the newly created filter instance (note that it is
893 * also retrievable directly through AVFilterGraph.filters or with
894 * avfilter_graph_get_filter()) on success or NULL on failure.
896 AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
897 const AVFilter *filter,
901 * Get a filter instance identified by instance name from graph.
903 * @param graph filter graph to search through.
904 * @param name filter instance name (should be unique in the graph).
905 * @return the pointer to the found filter instance or NULL if it
908 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, const char *name);
911 * Create and add a filter instance into an existing graph.
912 * The filter instance is created from the filter filt and inited
913 * with the parameters args and opaque.
915 * In case of success put in *filt_ctx the pointer to the created
916 * filter instance, otherwise set *filt_ctx to NULL.
918 * @param name the instance name to give to the created filter instance
919 * @param graph_ctx the filter graph
920 * @return a negative AVERROR error code in case of failure, a non
921 * negative value otherwise
923 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
924 const char *name, const char *args, void *opaque,
925 AVFilterGraph *graph_ctx);
928 * Enable or disable automatic format conversion inside the graph.
930 * Note that format conversion can still happen inside explicitly inserted
931 * scale and aresample filters.
933 * @param flags any of the AVFILTER_AUTO_CONVERT_* constants
935 void avfilter_graph_set_auto_convert(AVFilterGraph *graph, unsigned flags);
938 AVFILTER_AUTO_CONVERT_ALL = 0, /**< all automatic conversions enabled */
939 AVFILTER_AUTO_CONVERT_NONE = -1, /**< all automatic conversions disabled */
943 * Check validity and configure all the links and formats in the graph.
945 * @param graphctx the filter graph
946 * @param log_ctx context used for logging
947 * @return >= 0 in case of success, a negative AVERROR code otherwise
949 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
952 * Free a graph, destroy its links, and set *graph to NULL.
953 * If *graph is NULL, do nothing.
955 void avfilter_graph_free(AVFilterGraph **graph);
958 * A linked-list of the inputs/outputs of the filter chain.
960 * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
961 * where it is used to communicate open (unlinked) inputs and outputs from and
963 * This struct specifies, per each not connected pad contained in the graph, the
964 * filter context and the pad index required for establishing a link.
966 typedef struct AVFilterInOut {
967 /** unique name for this input/output in the list */
970 /** filter context associated to this input/output */
971 AVFilterContext *filter_ctx;
973 /** index of the filt_ctx pad to use for linking */
976 /** next input/input in the list, NULL if this is the last */
977 struct AVFilterInOut *next;
981 * Allocate a single AVFilterInOut entry.
982 * Must be freed with avfilter_inout_free().
983 * @return allocated AVFilterInOut on success, NULL on failure.
985 AVFilterInOut *avfilter_inout_alloc(void);
988 * Free the supplied list of AVFilterInOut and set *inout to NULL.
989 * If *inout is NULL, do nothing.
991 void avfilter_inout_free(AVFilterInOut **inout);
994 * Add a graph described by a string to a graph.
996 * @note The caller must provide the lists of inputs and outputs,
997 * which therefore must be known before calling the function.
999 * @note The inputs parameter describes inputs of the already existing
1000 * part of the graph; i.e. from the point of view of the newly created
1001 * part, they are outputs. Similarly the outputs parameter describes
1002 * outputs of the already existing filters, which are provided as
1003 * inputs to the parsed filters.
1005 * @param graph the filter graph where to link the parsed graph context
1006 * @param filters string to be parsed
1007 * @param inputs linked list to the inputs of the graph
1008 * @param outputs linked list to the outputs of the graph
1009 * @return zero on success, a negative AVERROR code on error
1011 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
1012 AVFilterInOut *inputs, AVFilterInOut *outputs,
1016 * Add a graph described by a string to a graph.
1018 * In the graph filters description, if the input label of the first
1019 * filter is not specified, "in" is assumed; if the output label of
1020 * the last filter is not specified, "out" is assumed.
1022 * @param graph the filter graph where to link the parsed graph context
1023 * @param filters string to be parsed
1024 * @param inputs pointer to a linked list to the inputs of the graph, may be NULL.
1025 * If non-NULL, *inputs is updated to contain the list of open inputs
1026 * after the parsing, should be freed with avfilter_inout_free().
1027 * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
1028 * If non-NULL, *outputs is updated to contain the list of open outputs
1029 * after the parsing, should be freed with avfilter_inout_free().
1030 * @return non negative on success, a negative AVERROR code on error
1032 int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
1033 AVFilterInOut **inputs, AVFilterInOut **outputs,
1037 * Add a graph described by a string to a graph.
1039 * @param[in] graph the filter graph where to link the parsed graph context
1040 * @param[in] filters string to be parsed
1041 * @param[out] inputs a linked list of all free (unlinked) inputs of the
1042 * parsed graph will be returned here. It is to be freed
1043 * by the caller using avfilter_inout_free().
1044 * @param[out] outputs a linked list of all free (unlinked) outputs of the
1045 * parsed graph will be returned here. It is to be freed by the
1046 * caller using avfilter_inout_free().
1047 * @return zero on success, a negative AVERROR code on error
1049 * @note This function returns the inputs and outputs that are left
1050 * unlinked after parsing the graph and the caller then deals with
1052 * @note This function makes no reference whatsoever to already
1053 * existing parts of the graph and the inputs parameter will on return
1054 * contain inputs of the newly parsed part of the graph. Analogously
1055 * the outputs parameter will contain outputs of the newly created
1058 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
1059 AVFilterInOut **inputs,
1060 AVFilterInOut **outputs);
1063 * Send a command to one or more filter instances.
1065 * @param graph the filter graph
1066 * @param target the filter(s) to which the command should be sent
1067 * "all" sends to all filters
1068 * otherwise it can be a filter or filter instance name
1069 * which will send the command to all matching filters.
1070 * @param cmd the command to send, for handling simplicity all commands must be alphanumeric only
1071 * @param arg the argument for the command
1072 * @param res a buffer with size res_size where the filter(s) can return a response.
1074 * @returns >=0 on success otherwise an error code.
1075 * AVERROR(ENOSYS) on unsupported commands
1077 int avfilter_graph_send_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, char *res, int res_len, int flags);
1080 * Queue a command for one or more filter instances.
1082 * @param graph the filter graph
1083 * @param target the filter(s) to which the command should be sent
1084 * "all" sends to all filters
1085 * otherwise it can be a filter or filter instance name
1086 * which will send the command to all matching filters.
1087 * @param cmd the command to sent, for handling simplicity all commands must be alphanumeric only
1088 * @param arg the argument for the command
1089 * @param ts time at which the command should be sent to the filter
1091 * @note As this executes commands after this function returns, no return code
1092 * from the filter is provided, also AVFILTER_CMD_FLAG_ONE is not supported.
1094 int avfilter_graph_queue_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, int flags, double ts);
1098 * Dump a graph into a human-readable string representation.
1100 * @param graph the graph to dump
1101 * @param options formatting options; currently ignored
1102 * @return a string, or NULL in case of memory allocation failure;
1103 * the string must be freed using av_free
1105 char *avfilter_graph_dump(AVFilterGraph *graph, const char *options);
1108 * Request a frame on the oldest sink link.
1110 * If the request returns AVERROR_EOF, try the next.
1112 * Note that this function is not meant to be the sole scheduling mechanism
1113 * of a filtergraph, only a convenience function to help drain a filtergraph
1114 * in a balanced way under normal circumstances.
1116 * Also note that AVERROR_EOF does not mean that frames did not arrive on
1117 * some of the sinks during the process.
1118 * When there are multiple sink links, in case the requested link
1119 * returns an EOF, this may cause a filter to flush pending frames
1120 * which are sent to another sink link, although unrequested.
1122 * @return the return value of ff_request_frame(),
1123 * or AVERROR_EOF if all links returned AVERROR_EOF
1125 int avfilter_graph_request_oldest(AVFilterGraph *graph);
1131 #endif /* AVFILTER_AVFILTER_H */