The number of the filter inputs is not determined just by AVFilter.inputs.

The filter might add additional inputs during initialization depending on the options supplied to it.

Definition at line 156 of file avfilter.h.

The number of the filter outputs is not determined just by AVFilter.outputs.

The filter might add additional outputs during initialization depending on the options supplied to it.

Definition at line 162 of file avfilter.h.

The filter supports multithreading by splitting frames into multiple parts and processing them concurrently.

Definition at line 167 of file avfilter.h.

The filter is a "metadata" filter - it does not modify the frame data in any way.

It may only affect the metadata (i.e. those fields copied by av_frame_copy_props()).

More precisely, this means:

• video: the data of any frame output by the filter must be exactly equal to some frame that is received on one of its inputs. Furthermore, all frames produced on a given output must correspond to frames received on the same input and their order must be unchanged. Note that the filter may still drop or duplicate the frames.
• audio: the data produced by the filter on any of its outputs (viewed e.g. as an array of interleaved samples) must be exactly equal to the data received by the filter on one of its inputs.

Definition at line 183 of file avfilter.h.

The filter can create hardware frames using AVFilterContext.hw_device_ctx.

Definition at line 188 of file avfilter.h.

Some filters support a generic "enable" expression option that can be used to enable or disable a filter in the timeline.

Filters supporting this option have this flag set. When the enable expression is false, the default no-op filter_frame() function is called in place of the filter_frame() callback defined on each input pad, thus the frame is passed unchanged to the next filters.

Definition at line 197 of file avfilter.h.

Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will have its filter_frame() callback(s) called as usual even when the enable expression is false.

The filter will disable filtering within the filter_frame() callback(s) itself, for example executing code depending on the AVFilterContext->is_disabled value.

Definition at line 205 of file avfilter.h.

Handy mask to test whether the filter supports or no the timeline feature (internally or generically).

Definition at line 210 of file avfilter.h.

Process multiple parts of the frame concurrently.

Definition at line 271 of file avfilter.h.

Stop once a filter understood the command (for target=all for example), fast filters are favored automatically.

Definition at line 469 of file avfilter.h.

Only execute command when its fast (like a video out that supports contrast adjustment in hw)

Definition at line 470 of file avfilter.h.

A function pointer passed to the AVFilterGraph::execute callback to be executed multiple times, possibly in parallel.

Parameters

ctx the filter context the job belongs to

arg an opaque parameter passed through from AVFilterGraph::execute

jobnr the index of the job being executed

nb_jobs the total number of jobs

Returns

0 on success, a negative AVERROR on error

Definition at line 572 of file avfilter.h.

A function executing multiple jobs, possibly in parallel.

Parameters

ctx the filter context to which the jobs belong

func the function to be called multiple times

arg the argument to be passed to func

ret a nb_jobs-sized array to be filled with return values from each invocation of func

nb_jobs the number of jobs to execute

Returns

0 on success, a negative AVERROR on error

Definition at line 586 of file avfilter.h.

Definition at line 717 of file avfilter.h.

Return the LIBAVFILTER_VERSION_INT constant.

Definition at line 30 of file version.c.

Return the libavfilter build-time configuration.

Definition at line 36 of file version.c.

Return the libavfilter license.

Definition at line 41 of file version.c.

Get the name of an AVFilterPad.

Parameters

pads an array of AVFilterPads

pad_idx index of the pad in the array; it is the caller's responsibility to ensure the index is valid

Returns

name of the pad_idx'th pad in pads

Definition at line 987 of file avfilter.c.

Referenced by describe_filter_link(), get_filterpad_name(), print_digraph(), and print_formats_internal().

Get the type of an AVFilterPad.

Parameters

pads an array of AVFilterPads

pad_idx index of the pad in the array; it is the caller's responsibility to ensure the index is valid

Returns

type of the pad_idx'th pad in pads

Definition at line 992 of file avfilter.c.

Referenced by create_sink(), fg_create(), insert_trim(), lavfi_read_header(), main(), and show_filters().

Get the hardware frames context of a filter link.

Parameters

link an AVFilterLink

Returns

a ref-counted copy of the link's hw_frames_ctx field if there is a hardware frames context associated with the link or NULL otherwise. The returned AVBufferRef needs to be released with av_buffer_unref() when it is no longer used.

Definition at line 997 of file avfilter.c.

Referenced by print_link().

Get the number of elements in an AVFilter's inputs or outputs array.

Definition at line 631 of file avfilter.c.

Referenced by fg_create(), and show_filters().

Link two filters together.

Parameters

src the source filter

srcpad index of the output pad on the source filter

dst the destination filter

dstpad index of the input pad on the destination filter

Returns

zero on success

Definition at line 149 of file avfilter.c.

Referenced by avfilter_graph_parse(), avfilter_graph_parse_ptr(), avfilter_insert_filter(), configure_filtergraph(), configure_input_audio_filter(), configure_input_video_filter(), configure_output_audio_filter(), configure_output_video_filter(), create_sink(), init_filter_graph(), insert_filter(), insert_trim(), lavfi_read_header(), link_inputs(), and link_outputs().

Make the filter instance process a command.

It is recommended to use avfilter_graph_send_command().

Definition at line 610 of file avfilter.c.

Referenced by avfilter_graph_send_command(), and ff_inlink_process_commands().

Iterate over all registered filters.

Parameters

opaque a pointer where libavfilter will store the iteration state. Must point to NULL to start the iteration.

Returns

the next registered filter or NULL when the iteration is finished

Definition at line 634 of file allfilters.c.

Referenced by avfilter_get_by_name(), filter_child_class_iterate(), and show_filters().

Get a filter definition matching the given name.

Parameters

name the filter name to find

Returns

the filter definition, if any matching one is registered. NULL if none found.

Definition at line 647 of file allfilters.c.

Referenced by avfilter_graph_segment_create_filters(), configure_audio_filters(), configure_input_audio_filter(), configure_input_video_filter(), configure_output_audio_filter(), configure_output_video_filter(), configure_video_filters(), create_sink(), filter_parse(), init_filter(), init_filter_graph(), init_filters(), insert_filter(), insert_trim(), lavfi_read_header(), main(), and query_formats().

Initialize a filter with the supplied parameters.

Parameters

ctx uninitialized filter context to initialize

args Options to initialize the filter with. This must be a ':'-separated list of options in the 'key=value' form. May be NULL if the options have been set directly using the AVOptions API or there are no options that need to be set.

Returns

0 on success, a negative AVERROR on failure

Definition at line 959 of file avfilter.c.

Referenced by avfilter_graph_create_filter(), init_filter_graph(), insert_trim(), and main().

Initialize a filter with the supplied dictionary of options.

Parameters

ctx uninitialized filter context to initialize

options An AVDictionary filled with options for this filter. On return this parameter will be destroyed and replaced with a dict containing options that were not found. This dictionary must be freed by the caller. May be NULL, then this function is equivalent to avfilter_init_str() with the second parameter set to NULL.

Returns

0 on success, a negative AVERROR on failure

Note

This function and avfilter_init_str() do essentially the same thing, the difference is in manner in which the options are passed. It is up to the calling code to choose whichever is more preferable. The two functions also behave differently when some of the provided options are not declared as supported by the filter. In such a case, avfilter_init_str() will fail, but this function will leave those extra options in the options AVDictionary and continue as usual.

Definition at line 918 of file avfilter.c.

Referenced by avfilter_graph_segment_init(), avfilter_init_str(), configure_audio_filters(), configure_input_video_filter(), configure_video_filters(), init_filter(), init_filter_graph(), init_filters(), and lavfi_read_header().

Free a filter context.

This will also remove the filter from its filtergraph's list of filters.

Parameters

filter the filter to free

Definition at line 799 of file avfilter.c.

Referenced by avfilter_graph_create_filter(), avfilter_graph_free(), avfilter_graph_parse(), avfilter_graph_parse2(), avfilter_graph_parse_ptr(), avfilter_graph_segment_create_filters(), and main().

Insert a filter in the middle of an existing link.

Parameters

link the link into which the filter should be inserted

filt the filter to be inserted

filt_srcpad_idx the input pad on the filter to connect

filt_dstpad_idx the output pad on the filter to connect

Returns

zero on success

Definition at line 282 of file avfilter.c.

Referenced by query_formats().

Returns

AVClass for AVFilterContext.

See also

av_opt_find().

Definition at line 1660 of file avfilter.c.

Referenced by show_help_default().

Allocate a filter graph.

Returns

the allocated filter graph on success or NULL.

Examples

decode_filter_audio.c, decode_filter_video.c, filter_audio.c, and transcode.c.

Definition at line 85 of file avfiltergraph.c.

Referenced by configure_audio_filters(), configure_filtergraph(), fg_create(), init_filter(), init_filter_graph(), init_filters(), lavfi_read_header(), main(), and video_thread().

Create a new filter instance in a filter graph.

Parameters

graph graph in which the new filter will be used

filter the filter to create an instance of

name Name to give to the new instance (will be copied to AVFilterContext.name). This may be used by the caller to identify different filters, libavfilter itself assigns no semantics to this parameter. May be NULL.

Returns

the context of the newly created filter instance (note that it is also retrievable directly through AVFilterGraph.filters or with avfilter_graph_get_filter()) on success or NULL on failure.

Examples

decode_filter_audio.c, decode_filter_video.c, filter_audio.c, and transcode.c.

Definition at line 167 of file avfiltergraph.c.

Referenced by avfilter_graph_create_filter(), avfilter_graph_segment_create_filters(), configure_audio_filters(), configure_input_video_filter(), configure_video_filters(), init_filter(), init_filter_graph(), init_filters(), insert_trim(), lavfi_read_header(), and main().

Get a filter instance identified by instance name from graph.

Parameters

graph filter graph to search through.

name filter instance name (should be unique in the graph).

Returns

the pointer to the found filter instance or NULL if it cannot be found.

Definition at line 286 of file avfiltergraph.c.

A convenience wrapper that allocates and initializes a filter in a single step.

The filter instance is created from the filter filt and inited with the parameter args. opaque is currently ignored.

In case of success put in *filt_ctx the pointer to the created filter instance, otherwise set *filt_ctx to NULL.

Parameters

name the instance name to give to the created filter instance

graph_ctx the filter graph

Returns

a negative AVERROR error code in case of failure, a non negative value otherwise

Warning

Since the filter is initialized after this function successfully returns, you MUST NOT set any further options on it. If you need to do that, call avfilter_graph_alloc_filter(), followed by setting the options, followed by avfilter_init_dict() instead of this function.

Examples

decode_filter_audio.c, decode_filter_video.c, and transcode.c.

Definition at line 140 of file avfiltergraph.c.

Referenced by configure_audio_filters(), configure_input_audio_filter(), configure_output_audio_filter(), configure_output_video_filter(), create_sink(), init_filter(), init_filters(), insert_filter(), lavfi_read_header(), and query_formats().

Enable or disable automatic format conversion inside the graph.

Note that format conversion can still happen inside explicitly inserted scale and aresample filters.

Parameters

flags any of the AVFILTER_AUTO_CONVERT_* constants

Definition at line 162 of file avfiltergraph.c.

Referenced by configure_filtergraph(), and init().

Check validity and configure all the links and formats in the graph.

Parameters

graphctx the filter graph

log_ctx context used for logging

Returns

>= 0 in case of success, a negative AVERROR code otherwise

Examples

decode_filter_audio.c, decode_filter_video.c, filter_audio.c, and transcode.c.

Definition at line 1414 of file avfiltergraph.c.

Referenced by configure_filtergraph(), init_filter(), init_filter_graph(), init_filters(), lavfi_read_header(), and main().

Free a graph, destroy its links, and set *graph to NULL.

If *graph is NULL, do nothing.

Examples

decode_filter_audio.c, decode_filter_video.c, filter_audio.c, and transcode.c.

Definition at line 119 of file avfiltergraph.c.

Referenced by audio_thread(), cleanup_filtergraph(), configure_audio_filters(), fg_create(), fg_thread_uninit(), lavfi_read_close(), main(), and video_thread().

Allocate a single AVFilterInOut entry.

Must be freed with avfilter_inout_free().

Returns

allocated AVFilterInOut on success, NULL on failure.

Examples

decode_filter_audio.c, decode_filter_video.c, and transcode.c.

Definition at line 71 of file graphparser.c.

Referenced by configure_filtergraph(), init_filter(), and init_filters().

Free the supplied list of AVFilterInOut and set *inout to NULL.

If *inout is NULL, do nothing.

Examples

decode_filter_audio.c, decode_filter_video.c, and transcode.c.

Definition at line 76 of file graphparser.c.

Referenced by avfilter_graph_parse(), avfilter_graph_parse_ptr(), avfilter_graph_segment_link(), configure_filtergraph(), fg_create(), init_filter(), init_filters(), inout_add(), and lavfi_read_header().

Add a graph described by a string to a graph.

Note

The caller must provide the lists of inputs and outputs, which therefore must be known before calling the function.

The inputs parameter describes inputs of the already existing part of the graph; i.e. from the point of view of the newly created part, they are outputs. Similarly the outputs parameter describes outputs of the already existing filters, which are provided as inputs to the parsed filters.

Parameters

graph the filter graph where to link the parsed graph context

filters string to be parsed

inputs linked list to the inputs of the graph

outputs linked list to the outputs of the graph

Returns

zero on success, a negative AVERROR code on error

Definition at line 164 of file graphparser.c.

Referenced by main().

Add a graph described by a string to a graph.

In the graph filters description, if the input label of the first filter is not specified, "in" is assumed; if the output label of the last filter is not specified, "out" is assumed.

Parameters

graph the filter graph where to link the parsed graph context

filters string to be parsed

inputs pointer to a linked list to the inputs of the graph, may be NULL. If non-NULL, *inputs is updated to contain the list of open inputs after the parsing, should be freed with avfilter_inout_free().

outputs pointer to a linked list to the outputs of the graph, may be NULL. If non-NULL, *outputs is updated to contain the list of open outputs after the parsing, should be freed with avfilter_inout_free().

Returns

non negative on success, a negative AVERROR code on error

Examples

decode_filter_audio.c, decode_filter_video.c, and transcode.c.

Definition at line 920 of file graphparser.c.

Referenced by configure_filtergraph(), init_filter(), init_filters(), lavfi_read_header(), and main().

Add a graph described by a string to a graph.

Parameters

[in] graph the filter graph where to link the parsed graph context

[in] filters string to be parsed

[out] inputs a linked list of all free (unlinked) inputs of the parsed graph will be returned here. It is to be freed by the caller using avfilter_inout_free().

[out] outputs a linked list of all free (unlinked) outputs of the parsed graph will be returned here. It is to be freed by the caller using avfilter_inout_free().

Returns

zero on success, a negative AVERROR code on error

Note

This function returns the inputs and outputs that are left unlinked after parsing the graph and the caller then deals with them.

This function makes no reference whatsoever to already existing parts of the graph and the inputs parameter will on return contain inputs of the newly parsed part of the graph. Analogously the outputs parameter will contain outputs of the newly created filters.

Definition at line 138 of file graphparser.c.

Referenced by avfilter_graph_parse().

Parse a textual filtergraph description into an intermediate form.

This intermediate representation is intended to be modified by the caller as described in the documentation of AVFilterGraphSegment and its children, and then applied to the graph either manually or with other avfilter_graph_segment_*() functions. See the documentation for avfilter_graph_segment_apply() for the canonical way to apply AVFilterGraphSegment.

Parameters

graph Filter graph the parsed segment is associated with. Will only be used for logging and similar auxiliary purposes. The graph will not be actually modified by this function - the parsing results are instead stored in seg for further processing.

graph_str a string describing the filtergraph segment

flags reserved for future use, caller must set to 0 for now

seg A pointer to the newly-created AVFilterGraphSegment is written here on success. The graph segment is owned by the caller and must be freed with avfilter_graph_segment_free() before graph itself is freed.

Return values

non-negative number success

negative error code failure

Definition at line 460 of file graphparser.c.

Referenced by avfilter_graph_parse2(), avfilter_graph_parse_ptr(), and graph_parse().

Create filters specified in a graph segment.

Walk through the creation-pending AVFilterParams in the segment and create new filter instances for them. Creation-pending params are those where AVFilterParams.filter_name is non-NULL (and hence AVFilterParams.filter is NULL). All other AVFilterParams instances are ignored.

For any filter created by this function, the corresponding AVFilterParams.filter is set to the newly-created filter context, AVFilterParams.filter_name and AVFilterParams.instance_name are freed and set to NULL.

Parameters

seg the filtergraph segment to process

flags reserved for future use, caller must set to 0 for now

Return values

non-negative number Success, all creation-pending filters were successfully created

AVERROR_FILTER_NOT_FOUND some filter's name did not correspond to a known filter

another negative error code other failures

Note

Calling this function multiple times is safe, as it is idempotent.

Definition at line 516 of file graphparser.c.

Referenced by avfilter_graph_parse_ptr(), avfilter_graph_segment_apply(), and graph_parse().

Apply parsed options to filter instances in a graph segment.

Walk through all filter instances in the graph segment that have option dictionaries associated with them and apply those options with av_opt_set_dict2(..., AV_OPT_SEARCH_CHILDREN). AVFilterParams.opts is replaced by the dictionary output by av_opt_set_dict2(), which should be empty (NULL) if all options were successfully applied.

If any options could not be found, this function will continue processing all other filters and finally return AVERROR_OPTION_NOT_FOUND (unless another error happens). The calling program may then deal with unapplied options as it wishes.

Any creation-pending filters (see avfilter_graph_segment_create_filters()) present in the segment will cause this function to fail. AVFilterParams with no associated filter context are simply skipped.

Parameters

seg the filtergraph segment to process

flags reserved for future use, caller must set to 0 for now

Return values

non-negative number Success, all options were successfully applied.

AVERROR_OPTION_NOT_FOUND some options were not found in a filter

another negative error code other failures

Note

Calling this function multiple times is safe, as it is idempotent.

Definition at line 586 of file graphparser.c.

Referenced by avfilter_graph_parse_ptr(), and avfilter_graph_segment_apply().

Initialize all filter instances in a graph segment.

Walk through all filter instances in the graph segment and call avfilter_init_dict(..., NULL) on those that have not been initialized yet.

Any creation-pending filters (see avfilter_graph_segment_create_filters()) present in the segment will cause this function to fail. AVFilterParams with no associated filter context or whose filter context is already initialized, are simply skipped.

Parameters

seg the filtergraph segment to process

flags reserved for future use, caller must set to 0 for now

Return values

non-negative number Success, all filter instances were successfully initialized

negative error code failure

Note

Calling this function multiple times is safe, as it is idempotent.

Definition at line 616 of file graphparser.c.

Referenced by avfilter_graph_parse_ptr(), and avfilter_graph_segment_apply().

Link filters in a graph segment.

Walk through all filter instances in the graph segment and try to link all unlinked input and output pads. Any creation-pending filters (see avfilter_graph_segment_create_filters()) present in the segment will cause this function to fail. Disabled filters and already linked pads are skipped.

Every filter output pad that has a corresponding AVFilterPadParams with a non-NULL label is

• linked to the input with the matching label, if one exists;
• exported in the outputs linked list otherwise, with the label preserved. Unlabeled outputs are
• linked to the first unlinked unlabeled input in the next non-disabled filter in the chain, if one exists
• exported in the outputs linked list otherwise, with NULL label

Similarly, unlinked input pads are exported in the inputs linked list.

Parameters

seg the filtergraph segment to process

flags reserved for future use, caller must set to 0 for now

[out] inputs a linked list of all free (unlinked) inputs of the filters in this graph segment will be returned here. It is to be freed by the caller using avfilter_inout_free().

[out] outputs a linked list of all free (unlinked) outputs of the filters in this graph segment will be returned here. It is to be freed by the caller using avfilter_inout_free().

Return values

non-negative number success

negative error code failure

Note

Calling this function multiple times is safe, as it is idempotent.

Definition at line 814 of file graphparser.c.

Referenced by avfilter_graph_segment_apply().

Apply all filter/link descriptions from a graph segment to the associated filtergraph.

This functions is currently equivalent to calling the following in sequence:

• avfilter_graph_segment_create_filters();
• avfilter_graph_segment_apply_opts();
• avfilter_graph_segment_init();
• avfilter_graph_segment_link(); failing if any of them fails. This list may be extended in the future.

Since the above functions are idempotent, the caller may call some of them manually, then do some custom processing on the filtergraph, then call this function to do the rest.

Parameters

seg the filtergraph segment to process

flags reserved for future use, caller must set to 0 for now

[out] inputs passed to avfilter_graph_segment_link()

[out] outputs passed to avfilter_graph_segment_link()

Return values

non-negative number success

negative error code failure

Note

Calling this function multiple times is safe, as it is idempotent.

Definition at line 882 of file graphparser.c.

Referenced by avfilter_graph_parse2(), avfilter_graph_parse_ptr(), and graph_parse().

Free the provided AVFilterGraphSegment and everything associated with it.

Parameters

seg double pointer to the AVFilterGraphSegment to be freed. NULL will be written to this pointer on exit from this function.

Note

The filter contexts (AVFilterParams.filter) are owned by AVFilterGraph rather than AVFilterGraphSegment, so they are not freed.

Definition at line 276 of file graphparser.c.

Referenced by avfilter_graph_parse2(), avfilter_graph_parse_ptr(), avfilter_graph_segment_parse(), and graph_parse().

Send a command to one or more filter instances.

Parameters

graph the filter graph

target the filter(s) to which the command should be sent "all" sends to all filters otherwise it can be a filter or filter instance name which will send the command to all matching filters.

cmd the command to send, for handling simplicity all commands must be alphanumeric only

arg the argument for the command

res a buffer with size res_size where the filter(s) can return a response.

Returns

>=0 on success otherwise an error code. AVERROR(ENOSYS) on unsupported commands

Definition at line 1434 of file avfiltergraph.c.

Referenced by filter_frame(), and send_command().

Queue a command for one or more filter instances.

Parameters

graph the filter graph

target the filter(s) to which the command should be sent "all" sends to all filters otherwise it can be a filter or filter instance name which will send the command to all matching filters.

cmd the command to sent, for handling simplicity all commands must be alphanumeric only

arg the argument for the command

ts time at which the command should be sent to the filter

Note

As this executes commands after this function returns, no return code from the filter is provided, also AVFILTER_CMD_FLAG_ONE is not supported.

Definition at line 1464 of file avfiltergraph.c.

Referenced by send_command().

Dump a graph into a human-readable string representation.

Parameters

graph the graph to dump

options formatting options; currently ignored

Returns

a string, or NULL in case of memory allocation failure; the string must be freed using av_free

Definition at line 156 of file graphdump.c.

Referenced by lavfi_read_header().

Request a frame on the oldest sink link.

If the request returns AVERROR_EOF, try the next.

Note that this function is not meant to be the sole scheduling mechanism of a filtergraph, only a convenience function to help drain a filtergraph in a balanced way under normal circumstances.

Also note that AVERROR_EOF does not mean that frames did not arrive on some of the sinks during the process. When there are multiple sink links, in case the requested link returns an EOF, this may cause a filter to flush pending frames which are sent to another sink link, although unrequested.

Returns

the return value of ff_request_frame(), or AVERROR_EOF if all links returned AVERROR_EOF

Definition at line 1547 of file avfiltergraph.c.

Referenced by configure_filtergraph(), main(), and read_frames().