Libavfilter - graph-based frame editing library

Modules
	Buffer sink API
	Buffer source API

Files
file	avfilter.h
	Main libavfilter public API header.
file	version.h
	Libavfilter version macros.

Data Structures
struct	AVFilter
	Filter definition. More...
struct	AVFilterContext
	An instance of a filter. More...
struct	AVFilterLink
	A link between two filters. More...
struct	AVFilterGraph
struct	AVFilterInOut
	A linked-list of the inputs/outputs of the filter chain. More...

Macros
#define	AVFILTER_FLAG_DYNAMIC_INPUTS   (1 << 0)
	The number of the filter inputs is not determined just by AVFilter.inputs.
#define	AVFILTER_FLAG_DYNAMIC_OUTPUTS   (1 << 1)
	The number of the filter outputs is not determined just by AVFilter.outputs.
#define	AVFILTER_FLAG_SLICE_THREADS   (1 << 2)
	The filter supports multithreading by splitting frames into multiple parts and processing them concurrently.
#define	AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC   (1 << 16)
	Some filters support a generic "enable" expression option that can be used to enable or disable a filter in the timeline.
#define	AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL   (1 << 17)
	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.
#define	AVFILTER_FLAG_SUPPORT_TIMELINE   (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
	Handy mask to test whether the filter supports or no the timeline feature (internally or generically).
#define	AVFILTER_THREAD_SLICE   (1 << 0)
	Process multiple parts of the frame concurrently.
#define	AVFILTER_CMD_FLAG_ONE   1
	Stop once a filter understood the command (for target=all for example), fast filters are favored automatically.
#define	AVFILTER_CMD_FLAG_FAST   2
	Only execute command when its fast (like a video out that supports contrast adjustment in hw)

Typedefs
typedef 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, possibly in parallel.
typedef 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.

Enumerations
enum	{ AVFILTER_AUTO_CONVERT_ALL = 0, AVFILTER_AUTO_CONVERT_NONE = -1 }

Functions
unsigned	avfilter_version (void)
	Return the LIBAVFILTER_VERSION_INT constant.
const char *	avfilter_configuration (void)
	Return the libavfilter build-time configuration.
const char *	avfilter_license (void)
	Return the libavfilter license.
attribute_deprecated int	avfilter_ref_get_channels (AVFilterBufferRef *ref)
	Get the number of channels of a buffer reference.
int	avfilter_pad_count (const AVFilterPad *pads)
	Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
const char *	avfilter_pad_get_name (const AVFilterPad *pads, int pad_idx)
	Get the name of an AVFilterPad.
enum AVMediaType	avfilter_pad_get_type (const AVFilterPad *pads, int pad_idx)
	Get the type of an AVFilterPad.
int	avfilter_link (AVFilterContext *src, unsigned srcpad, AVFilterContext *dst, unsigned dstpad)
	Link two filters together.
void	avfilter_link_free (AVFilterLink **link)
	Free the link in *link, and set its pointer to NULL.
int	avfilter_link_get_channels (AVFilterLink *link)
	Get the number of channels of a link.
void	avfilter_link_set_closed (AVFilterLink *link, int closed)
	Set the closed field of a link.
int	avfilter_config_links (AVFilterContext *filter)
	Negotiate the media format, dimensions, etc of all inputs to a filter.
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.
void	avfilter_register_all (void)
	Initialize the filter system.
int	avfilter_register (AVFilter *filter)
	Register a filter.
const AVFilter *	avfilter_get_by_name (const char *name)
	Get a filter definition matching the given name.
const AVFilter *	avfilter_next (const AVFilter *prev)
	Iterate over all registered filters.
int	avfilter_init_str (AVFilterContext *ctx, const char *args)
	Initialize a filter with the supplied parameters.
int	avfilter_init_dict (AVFilterContext *ctx, AVDictionary **options)
	Initialize a filter with the supplied dictionary of options.
void	avfilter_free (AVFilterContext *filter)
	Free a filter context.
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.
const AVClass *	avfilter_get_class (void)
AVFilterGraph *	avfilter_graph_alloc (void)
	Allocate a filter graph.
AVFilterContext *	avfilter_graph_alloc_filter (AVFilterGraph *graph, const AVFilter *filter, const char *name)
	Create a new filter instance in a filter graph.
AVFilterContext *	avfilter_graph_get_filter (AVFilterGraph *graph, char *name)
	Get a filter instance with name name from graph.
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.
void	avfilter_graph_set_auto_convert (AVFilterGraph *graph, unsigned flags)
	Enable or disable automatic format conversion inside the graph.
int	avfilter_graph_config (AVFilterGraph *graphctx, void *log_ctx)
	Check validity and configure all the links and formats in the graph.
void	avfilter_graph_free (AVFilterGraph **graph)
	Free a graph, destroy its links, and set *graph to NULL.
AVFilterInOut *	avfilter_inout_alloc (void)
	Allocate a single AVFilterInOut entry.
void	avfilter_inout_free (AVFilterInOut **inout)
	Free the supplied list of AVFilterInOut and set *inout to NULL.
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.
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.
int	avfilter_graph_parse2 (AVFilterGraph *graph, const char *filters, AVFilterInOut **inputs, AVFilterInOut **outputs)
	Add a graph described by a string to a graph.
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.
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.
char *	avfilter_graph_dump (AVFilterGraph *graph, const char *options)
	Dump a graph into a human-readable string representation.
int	avfilter_graph_request_oldest (AVFilterGraph *graph)
	Request a frame on the oldest sink link.

Detailed Description

Macro Definition Documentation

#define AVFILTER_FLAG_DYNAMIC_INPUTS   (1 << 0)

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 431 of file avfilter.h.

Referenced by show_filters().

#define AVFILTER_FLAG_DYNAMIC_OUTPUTS   (1 << 1)

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 437 of file avfilter.h.

Referenced by show_filters().

#define AVFILTER_FLAG_SLICE_THREADS   (1 << 2)

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

Definition at line 442 of file avfilter.h.

Referenced by avfilter_init_dict(), and show_filters().

#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC   (1 << 16)

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 451 of file avfilter.h.

Referenced by ff_filter_frame_framed().

#define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL   (1 << 17)

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 459 of file avfilter.h.

#define AVFILTER_FLAG_SUPPORT_TIMELINE   (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)

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

Definition at line 464 of file avfilter.h.

Referenced by avfilter_register(), set_enable_expr(), and show_filters().

#define AVFILTER_THREAD_SLICE   (1 << 0)

Process multiple parts of the frame concurrently.

Definition at line 628 of file avfilter.h.

Referenced by avfilter_init_dict().

#define AVFILTER_CMD_FLAG_ONE   1

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

Definition at line 963 of file avfilter.h.

Referenced by avfilter_graph_queue_command(), avfilter_graph_send_command(), check_keyboard_interaction(), and filter_frame().

#define AVFILTER_CMD_FLAG_FAST   2

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

Definition at line 964 of file avfilter.h.

Referenced by avfilter_graph_send_command().

Typedef Documentation

typedef 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, 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 1150 of file avfilter.h.

typedef 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.

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 1164 of file avfilter.h.

Enumeration Type Documentation

anonymous enum

Enumerator:

AVFILTER_AUTO_CONVERT_ALL	all automatic conversions enabled
AVFILTER_AUTO_CONVERT_NONE	all automatic conversions disabled

Definition at line 1318 of file avfilter.h.

Function Documentation

unsigned avfilter_version

(

void

)

Return the LIBAVFILTER_VERSION_INT constant.

Definition at line 70 of file avfilter.c.

const char* avfilter_configuration

(

void

)

Return the libavfilter build-time configuration.

Definition at line 76 of file avfilter.c.

const char* avfilter_license

(

void

)

Return the libavfilter license.

Definition at line 81 of file avfilter.c.

attribute_deprecated int avfilter_ref_get_channels

(

AVFilterBufferRef *

ref

)

Get the number of channels of a buffer reference.

Definition at line 31 of file audio.c.

int avfilter_pad_count

(

const AVFilterPad *

pads

)

Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.

AVFilter.inputs/outputs).

Definition at line 517 of file avfilter.c.

Referenced by ff_filter_alloc().

const char* avfilter_pad_get_name	(	const AVFilterPad *	pads,
		int	pad_idx
	)

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 982 of file avfilter.c.

enum AVMediaType avfilter_pad_get_type	(	const AVFilterPad *	pads,
		int	pad_idx
	)

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 987 of file avfilter.c.

Referenced by configure_input_filter(), configure_output_filter(), create_sink(), init_input_filter(), init_output_filter(), insert_trim(), and open_output_file().

int avfilter_link	(	AVFilterContext *	src,
		unsigned	srcpad,
		AVFilterContext *	dst,
		unsigned	dstpad
	)

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 128 of file avfilter.c.

Referenced by avfilter_graph_parse(), avfilter_insert_filter(), configure_input_audio_filter(), configure_input_video_filter(), configure_output_audio_filter(), configure_output_video_filter(), create_sink(), init_filter_graph(), insert_trim(), lavfi_read_header(), and link_filter().

void avfilter_link_free

(

AVFilterLink **

link

)

Free the link in *link, and set its pointer to NULL.

Definition at line 162 of file avfilter.c.

Referenced by free_link().

int avfilter_link_get_channels

(

AVFilterLink *

link

)

Get the number of channels of a link.

Definition at line 172 of file avfilter.c.

Referenced by lavfi_read_header(), main(), and transcode_init().

void avfilter_link_set_closed	(	AVFilterLink *	link,
		int	closed
	)

Set the closed field of a link.

Definition at line 177 of file avfilter.c.

int avfilter_config_links

(

AVFilterContext *

filter

)

Negotiate the media format, dimensions, etc of all inputs to a filter.

Parameters

filter

the filter to negotiate the properties for its inputs

Returns

zero on successful negotiation

Definition at line 219 of file avfilter.c.

Referenced by avfilter_config_links(), and graph_config_links().

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.

It is recommended to use avfilter_graph_send_command().

Definition at line 437 of file avfilter.c.

Referenced by avfilter_graph_send_command(), and ff_filter_frame_framed().

void avfilter_register_all

(

void

)

Initialize the filter system.

Register all builtin filters.

Definition at line 40 of file allfilters.c.

Referenced by lavfi_read_header(), and main().

int avfilter_register

(

AVFilter *

filter

)

Register a filter.

This is only needed if you plan to use avfilter_get_by_name later to lookup the AVFilter structure by name. A filter can still by instantiated with avfilter_graph_alloc_filter even if it is not registered.

Parameters

filter

the filter to register

Returns

0 if the registration was successful, a negative value otherwise

Definition at line 478 of file avfilter.c.

const AVFilter* avfilter_get_by_name

(

const char *

name

)

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 464 of file avfilter.c.

Referenced by configure_input_audio_filter(), configure_input_video_filter(), configure_output_audio_filter(), configure_output_video_filter(), create_filter(), create_sink(), graph_insert_fifos(), init_filter_graph(), init_filters(), insert_trim(), lavfi_read_header(), main(), and query_formats().

const AVFilter* avfilter_next

(

const AVFilter *

prev

)

Iterate over all registered filters.

Returns

If prev is non-NULL, next registered filter after prev or NULL if prev is the last filter. If prev is NULL, return the first registered filter.

Definition at line 501 of file avfilter.c.

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

int avfilter_init_str	(	AVFilterContext *	ctx,
		const char *	args
	)

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 860 of file avfilter.c.

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

int avfilter_init_dict	(	AVFilterContext *	ctx,
		AVDictionary **	options
	)

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 823 of file avfilter.c.

Referenced by init_filter_graph().

void avfilter_free

(

AVFilterContext *

filter

)

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 698 of file avfilter.c.

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

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.

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 182 of file avfilter.c.

Referenced by graph_insert_fifos(), and query_formats().

const AVClass* avfilter_get_class

(

void

)

Returns

AVClass for AVFilterContext.

See Also

av_opt_find().

Definition at line 1165 of file avfilter.c.

Referenced by show_help_default().

AVFilterGraph* avfilter_graph_alloc

(

void

)

Allocate a filter graph.

Examples:

filter_audio.c, filtering_audio.c, and filtering_video.c.

Definition at line 77 of file avfiltergraph.c.

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

AVFilterContext* avfilter_graph_alloc_filter	(	AVFilterGraph *	graph,
		const AVFilter *	filter,
		const char *	name
	)

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 or failure.

Examples:

filter_audio.c.

Definition at line 179 of file avfiltergraph.c.

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

AVFilterContext* avfilter_graph_get_filter	(	AVFilterGraph *	graph,
		char *	name
	)

Get a filter instance with name name from graph.

Returns

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

Definition at line 284 of file avfiltergraph.c.

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.

The filter instance is created from the filter filt and inited with the parameters args and opaque.

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

Examples:

filtering_audio.c, and filtering_video.c.

Definition at line 151 of file avfiltergraph.c.

Referenced by configure_input_audio_filter(), configure_input_video_filter(), configure_output_audio_filter(), configure_output_video_filter(), create_sink(), graph_insert_fifos(), init_filters(), lavfi_read_header(), and query_formats().

void avfilter_graph_set_auto_convert	(	AVFilterGraph *	graph,
		unsigned	flags
	)

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 174 of file avfiltergraph.c.

Referenced by choose_pix_fmts().

int avfilter_graph_config	(	AVFilterGraph *	graphctx,
		void *	log_ctx
	)

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:

filter_audio.c, filtering_audio.c, and filtering_video.c.

Definition at line 1187 of file avfiltergraph.c.

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

void avfilter_graph_free

(

AVFilterGraph **

graph

)

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

If *graph is NULL, do nothing.

Examples:

filter_audio.c, filtering_audio.c, and filtering_video.c.

Definition at line 108 of file avfiltergraph.c.

Referenced by configure_filtergraph(), ffmpeg_cleanup(), lavfi_read_close(), main(), stream_component_close(), and video_thread().

AVFilterInOut* avfilter_inout_alloc

(

void

)

Allocate a single AVFilterInOut entry.

Must be freed with avfilter_inout_free().

Returns

allocated AVFilterInOut on success, NULL on failure.

Examples:

filtering_audio.c, and filtering_video.c.

Definition at line 177 of file graphparser.c.

Referenced by init_filters().

void avfilter_inout_free

(

AVFilterInOut **

inout

)

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

If *inout is NULL, do nothing.

Examples:

filtering_audio.c, and filtering_video.c.

Definition at line 182 of file graphparser.c.

Referenced by avfilter_graph_parse(), avfilter_graph_parse2(), avfilter_graph_parse_ptr(), configure_filtergraph(), init_filters(), init_output_filter(), and lavfi_read_header().

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.

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 grap 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 455 of file graphparser.c.

Referenced by avfilter_graph_parse(), and main().

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.

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:

filtering_audio.c, and filtering_video.c.

Definition at line 525 of file graphparser.c.

Referenced by avfilter_graph_parse(), init_filters(), lavfi_read_header(), and main().

int avfilter_graph_parse2	(	AVFilterGraph *	graph,
		const char *	filters,
		AVFilterInOut **	inputs,
		AVFilterInOut **	outputs
	)

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 386 of file graphparser.c.

Referenced by avfilter_graph_parse(), and configure_filtergraph().

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.

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 1205 of file avfiltergraph.c.

Referenced by avfilter_graph_send_command(), check_keyboard_interaction(), and filter_frame().

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.

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 alphanummeric 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 1235 of file avfiltergraph.c.

Referenced by check_keyboard_interaction().

char* avfilter_graph_dump	(	AVFilterGraph *	graph,
		const char *	options
	)

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 153 of file graphdump.c.

Referenced by lavfi_read_header().

int avfilter_graph_request_oldest

(

AVFilterGraph *

graph

)

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 1309 of file avfiltergraph.c.

Referenced by main(), and transcode_from_filter().