#ifndef AVFILTER_AVFILTER_H
#define AVFILTER_AVFILTER_H
+/**
+ * @file
+ * @ingroup lavfi
+ * Main libavfilter public API header
+ */
+
+/**
+ * @defgroup lavfi Libavfilter - graph-based frame editing library
+ * @{
+ */
+
+#include "libavutil/attributes.h"
#include "libavutil/avutil.h"
+#include "libavutil/frame.h"
#include "libavutil/log.h"
#include "libavutil/samplefmt.h"
#include "libavutil/pixfmt.h"
typedef struct AVFilterPad AVFilterPad;
typedef struct AVFilterFormats AVFilterFormats;
+#if FF_API_AVFILTERBUFFER
/**
* A reference-counted buffer data type used by the filter system. Filters
* should not store pointers to this structure directly, but instead use the
/**
* Copy properties of src to dst, without copying the actual data
*/
+attribute_deprecated
void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src);
/**
* @return a new reference to the buffer with the same properties as the
* old, excluding any permissions denied by pmask
*/
+attribute_deprecated
AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
/**
* buffer, the buffer itself is also automatically freed.
*
* @param ref reference to the buffer, may be NULL
+ *
+ * @note it is recommended to use avfilter_unref_bufferp() instead of this
+ * function
*/
+attribute_deprecated
void avfilter_unref_buffer(AVFilterBufferRef *ref);
+/**
+ * Remove a reference to a buffer and set the pointer to NULL.
+ * If this is the last reference to the buffer, the buffer itself
+ * is also automatically freed.
+ *
+ * @param ref pointer to the buffer reference
+ */
+attribute_deprecated
+void avfilter_unref_bufferp(AVFilterBufferRef **ref);
+#endif
+
#if FF_API_AVFILTERPAD_PUBLIC
/**
* A filter pad used for either input or output.
*
* Input pads only.
*/
- int min_perms;
+ attribute_deprecated int min_perms;
/**
* Permissions which are not accepted on incoming buffers. Any buffer
*
* Input pads only.
*/
- int rej_perms;
+ attribute_deprecated int rej_perms;
/**
- * Callback called before passing the first slice of a new frame. If
- * NULL, the filter layer will default to storing a reference to the
- * picture inside the link structure.
- *
- * Input video pads only.
+ * @deprecated unused
*/
- void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
+ int (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
/**
* Callback function to get a video buffer. If NULL, the filter system will
*
* Input video pads only.
*/
- AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
+ AVFrame *(*get_video_buffer)(AVFilterLink *link, int w, int h);
/**
* Callback function to get an audio buffer. If NULL, the filter system will
*
* Input audio pads only.
*/
- AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
- int nb_samples);
+ AVFrame *(*get_audio_buffer)(AVFilterLink *link, int nb_samples);
/**
- * Callback called after the slices of a frame are completely sent. If
- * NULL, the filter layer will default to releasing the reference stored
- * in the link structure during start_frame().
- *
- * Input video pads only.
+ * @deprecated unused
*/
- void (*end_frame)(AVFilterLink *link);
+ int (*end_frame)(AVFilterLink *link);
/**
- * Slice drawing callback. This is where a filter receives video data
- * and should do its processing.
- *
- * Input video pads only.
+ * @deprecated unused
*/
- void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
+ int (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
/**
- * Samples filtering callback. This is where a filter receives audio data
- * and should do its processing.
+ * Filtering callback. This is where a filter receives a frame with
+ * audio/video data and should do its processing.
*
- * Input audio pads only.
+ * Input pads only.
+ *
+ * @return >= 0 on success, a negative AVERROR on error. This function
+ * must ensure that samplesref is properly unreferenced on error if it
+ * hasn't been passed on to another filter.
*/
- void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
+ int (*filter_frame)(AVFilterLink *link, AVFrame *frame);
/**
* Frame poll callback. This returns the number of immediately available
* input pads only.
*/
int needs_fifo;
+
+ int needs_writable;
};
#endif
+/**
+ * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
+ * AVFilter.inputs/outputs).
+ */
+int avfilter_pad_count(const AVFilterPad *pads);
+
/**
* Get the name of an AVFilterPad.
*
*
* @return name of the pad_idx'th pad in pads
*/
-const char *avfilter_pad_get_name(AVFilterPad *pads, int pad_idx);
+const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
/**
* Get the type of an AVFilterPad.
*
* @return type of the pad_idx'th pad in pads
*/
-enum AVMediaType avfilter_pad_get_type(AVFilterPad *pads, int pad_idx);
+enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
+
+/**
+ * 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.
+ */
+#define AVFILTER_FLAG_DYNAMIC_INPUTS (1 << 0)
+/**
+ * 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.
+ */
+#define AVFILTER_FLAG_DYNAMIC_OUTPUTS (1 << 1)
+/**
+ * The filter supports multithreading by splitting frames into multiple parts
+ * and processing them concurrently.
+ */
+#define AVFILTER_FLAG_SLICE_THREADS (1 << 2)
/**
* Filter definition. This defines the pads a filter contains, and all the
* callback functions used to interact with the filter.
*/
typedef struct AVFilter {
- const char *name; ///< filter name
+ /**
+ * Filter name. Must be non-NULL and unique among filters.
+ */
+ const char *name;
/**
- * A description for the filter. You should use the
- * NULL_IF_CONFIG_SMALL() macro to define it.
+ * A description of the filter. May be NULL.
+ *
+ * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
*/
const char *description;
- const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
- const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
+ /**
+ * List of inputs, terminated by a zeroed element.
+ *
+ * NULL if there are no (static) inputs. Instances of filters with
+ * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
+ * this list.
+ */
+ const AVFilterPad *inputs;
+ /**
+ * List of outputs, terminated by a zeroed element.
+ *
+ * NULL if there are no (static) outputs. Instances of filters with
+ * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
+ * this list.
+ */
+ const AVFilterPad *outputs;
+
+ /**
+ * A class for the private data, used to declare filter private AVOptions.
+ * This field is NULL for filters that do not declare any options.
+ *
+ * If this field is non-NULL, the first member of the filter private data
+ * must be a pointer to AVClass, which will be set by libavfilter generic
+ * code to this class.
+ */
+ const AVClass *priv_class;
+
+ /**
+ * A combination of AVFILTER_FLAG_*
+ */
+ int flags;
/*****************************************************************
* All fields below this line are not part of the public API. They
*/
/**
- * Filter initialization function. Args contains the user-supplied
- * parameters. FIXME: maybe an AVOption-based system would be better?
+ * Filter initialization function.
+ *
+ * This callback will be called only once during the filter lifetime, after
+ * all the options have been set, but before links between filters are
+ * established and format negotiation is done.
+ *
+ * Basic filter initialization should be done here. Filters with dynamic
+ * inputs and/or outputs should create those inputs/outputs here based on
+ * provided options. No more changes to this filter's inputs/outputs can be
+ * done after this callback.
+ *
+ * This callback must not assume that the filter links exist or frame
+ * parameters are known.
+ *
+ * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
+ * initialization fails, so this callback does not have to clean up on
+ * failure.
+ *
+ * @return 0 on success, a negative AVERROR on failure
+ */
+ int (*init)(AVFilterContext *ctx);
+
+ /**
+ * Should be set instead of @ref AVFilter.init "init" by the filters that
+ * want to pass a dictionary of AVOptions to nested contexts that are
+ * allocated during init.
+ *
+ * On return, the options dict should be freed and replaced with one that
+ * contains all the options which could not be processed by this filter (or
+ * with NULL if all the options were processed).
+ *
+ * Otherwise the semantics is the same as for @ref AVFilter.init "init".
*/
- int (*init)(AVFilterContext *ctx, const char *args);
+ int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
/**
- * Filter uninitialization function. Should deallocate any memory held
- * by the filter, release any buffer references, etc. This does not need
- * to deallocate the AVFilterContext->priv memory itself.
+ * Filter uninitialization function.
+ *
+ * Called only once right before the filter is freed. Should deallocate any
+ * memory held by the filter, release any buffer references, etc. It does
+ * not need to deallocate the AVFilterContext.priv memory itself.
+ *
+ * This callback may be called even if @ref AVFilter.init "init" was not
+ * called or failed, so it must be prepared to handle such a situation.
*/
void (*uninit)(AVFilterContext *ctx);
/**
- * Queries formats supported by the filter and its pads, and sets the
- * in_formats for links connected to its output pads, and out_formats
- * for links connected to its input pads.
+ * Query formats supported by the filter on its inputs and outputs.
+ *
+ * This callback is called after the filter is initialized (so the inputs
+ * and outputs are fixed), shortly before the format negotiation. This
+ * callback may be called more than once.
+ *
+ * This callback must set AVFilterLink.out_formats on every input link and
+ * AVFilterLink.in_formats on every output link to a list of pixel/sample
+ * formats that the filter supports on that link. For audio links, this
+ * filter must also set @ref AVFilterLink.in_samplerates "in_samplerates" /
+ * @ref AVFilterLink.out_samplerates "out_samplerates" and
+ * @ref AVFilterLink.in_channel_layouts "in_channel_layouts" /
+ * @ref AVFilterLink.out_channel_layouts "out_channel_layouts" analogously.
+ *
+ * This callback may be NULL for filters with one input, in which case
+ * libavfilter assumes that it supports all input formats and preserves
+ * them on output.
*
* @return zero on success, a negative value corresponding to an
* AVERROR code otherwise
int (*query_formats)(AVFilterContext *);
int priv_size; ///< size of private data to allocate for the filter
+
+ /**
+ * Used by the filter registration system. Must not be touched by any other
+ * code.
+ */
+ struct AVFilter *next;
} AVFilter;
+/**
+ * Process multiple parts of the frame concurrently.
+ */
+#define AVFILTER_THREAD_SLICE (1 << 0)
+
+typedef struct AVFilterInternal AVFilterInternal;
+
/** An instance of a filter */
struct AVFilterContext {
const AVClass *av_class; ///< needed for av_log()
- AVFilter *filter; ///< the AVFilter of which this is an instance
+ const AVFilter *filter; ///< the AVFilter of which this is an instance
char *name; ///< name of this filter instance
AVFilterPad *input_pads; ///< array of input pads
AVFilterLink **inputs; ///< array of pointers to input links
#if FF_API_FOO_COUNT
- unsigned input_count; ///< @deprecated use nb_inputs
+ attribute_deprecated unsigned input_count; ///< @deprecated use nb_inputs
#endif
unsigned nb_inputs; ///< number of input pads
AVFilterPad *output_pads; ///< array of output pads
AVFilterLink **outputs; ///< array of pointers to output links
#if FF_API_FOO_COUNT
- unsigned output_count; ///< @deprecated use nb_outputs
+ attribute_deprecated unsigned output_count; ///< @deprecated use nb_outputs
#endif
unsigned nb_outputs; ///< number of output pads
void *priv; ///< private data for use by the filter
+
+ struct AVFilterGraph *graph; ///< filtergraph this filter belongs to
+
+ /**
+ * Type of multithreading being allowed/used. A combination of
+ * AVFILTER_THREAD_* flags.
+ *
+ * May be set by the caller before initializing the filter to forbid some
+ * or all kinds of multithreading for this filter. The default is allowing
+ * everything.
+ *
+ * When the filter is initialized, this field is combined using bit AND with
+ * AVFilterGraph.thread_type to get the final mask used for determining
+ * allowed threading types. I.e. a threading type needs to be set in both
+ * to be allowed.
+ *
+ * After the filter is initialzed, libavfilter sets this field to the
+ * threading type that is actually used (0 for no multithreading).
+ */
+ int thread_type;
+
+ /**
+ * An opaque struct for libavfilter internal use.
+ */
+ AVFilterInternal *internal;
};
/**
AVFilterContext *dst; ///< dest filter
AVFilterPad *dstpad; ///< input pad on the dest filter
- /** stage of the initialization of the link properties (dimensions, etc) */
- enum {
- AVLINK_UNINIT = 0, ///< not started
- AVLINK_STARTINIT, ///< started, but incomplete
- AVLINK_INIT ///< complete
- } init_state;
-
enum AVMediaType type; ///< filter media type
/* These parameters apply only to video */
int h; ///< agreed upon image height
AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
/* These two parameters apply only to audio */
- uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/audioconvert.h)
+ uint64_t channel_layout; ///< channel layout of current buffer (see libavutil/channel_layout.h)
int sample_rate; ///< samples per second
int format; ///< agreed upon media format
- /**
- * Lists of formats supported by the input and output filters respectively.
- * These lists are used for negotiating the format to actually be used,
- * which will be loaded into the format member, above, when chosen.
- */
- AVFilterFormats *in_formats;
- AVFilterFormats *out_formats;
-
- /**
- * The buffer reference currently being sent across the link by the source
- * filter. This is used internally by the filter system to allow
- * automatic copying of buffers which do not have sufficient permissions
- * for the destination. This should not be accessed directly by the
- * filters.
- */
- AVFilterBufferRef *src_buf;
-
- AVFilterBufferRef *cur_buf;
- AVFilterBufferRef *out_buf;
-
/**
* Define the time base used by the PTS of the frames/samples
* which will pass through this link.
* New public fields should be added right above.
*****************************************************************
*/
+ /**
+ * Lists of formats supported by the input and output filters respectively.
+ * These lists are used for negotiating the format to actually be used,
+ * which will be loaded into the format member, above, when chosen.
+ */
+ AVFilterFormats *in_formats;
+ AVFilterFormats *out_formats;
+
/**
* Lists of channel layouts and sample rates used for automatic
* negotiation.
* Last buffer before EOF will be padded with silence.
*/
int request_samples;
+
+ /** stage of the initialization of the link properties (dimensions, etc) */
+ enum {
+ AVLINK_UNINIT = 0, ///< not started
+ AVLINK_STARTINIT, ///< started, but incomplete
+ AVLINK_INIT ///< complete
+ } init_state;
};
/**
*/
int avfilter_config_links(AVFilterContext *filter);
+#if FF_API_AVFILTERBUFFER
/**
* Create a buffer reference wrapped around an already allocated image
* buffer.
* @param h the height of the image specified by the data and linesize arrays
* @param format the pixel format of the image specified by the data and linesize arrays
*/
+attribute_deprecated
AVFilterBufferRef *
avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int perms,
- int w, int h, enum PixelFormat format);
+ int w, int h, enum AVPixelFormat format);
/**
* Create an audio buffer reference wrapped around an already
* @param sample_fmt the format of each sample in the buffer to allocate
* @param channel_layout the channel layout of the buffer
*/
+attribute_deprecated
AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
int linesize,
int perms,
int nb_samples,
enum AVSampleFormat sample_fmt,
uint64_t channel_layout);
+#endif
/** Initialize the filter system. Register all builtin filters. */
void avfilter_register_all(void);
+#if FF_API_OLD_FILTER_REGISTER
/** Uninitialize the filter system. Unregister all filters. */
+attribute_deprecated
void avfilter_uninit(void);
+#endif
/**
* 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_open even if it is not
- * registered.
+ * filter can still by instantiated with avfilter_graph_alloc_filter even if it
+ * is not registered.
*
* @param filter the filter to register
* @return 0 if the registration was succesfull, a negative value
*/
AVFilter *avfilter_get_by_name(const char *name);
+/**
+ * Iterate over all registered filters.
+ * @return 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.
+ */
+const AVFilter *avfilter_next(const AVFilter *prev);
+
+#if FF_API_OLD_FILTER_REGISTER
/**
* If filter is NULL, returns a pointer to the first registered filter pointer,
* if filter is non-NULL, returns the next pointer after filter.
* If the returned pointer points to NULL, the last registered filter
* was already reached.
+ * @deprecated use avfilter_next()
*/
+attribute_deprecated
AVFilter **av_filter_next(AVFilter **filter);
+#endif
+#if FF_API_AVFILTER_OPEN
/**
* Create a filter instance.
*
* @param filter the filter to create an instance of
* @param inst_name Name to give to the new instance. Can be NULL for none.
* @return >= 0 in case of success, a negative error code otherwise
+ * @deprecated use avfilter_graph_alloc_filter() instead
*/
+attribute_deprecated
int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
+#endif
+
+#if FF_API_AVFILTER_INIT_FILTER
/**
* Initialize a filter.
*
* of this parameter varies by filter.
* @return zero on success
*/
+attribute_deprecated
int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
+#endif
+
+/**
+ * Initialize a filter with the supplied parameters.
+ *
+ * @param ctx uninitialized filter context to initialize
+ * @param 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.
+ * @return 0 on success, a negative AVERROR on failure
+ */
+int avfilter_init_str(AVFilterContext *ctx, const char *args);
+
+/**
+ * Initialize a filter with the supplied dictionary of options.
+ *
+ * @param ctx uninitialized filter context to initialize
+ * @param 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.
+ * @return 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.
+ */
+int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
/**
- * Free a filter context.
+ * Free a filter context. This will also remove the filter from its
+ * filtergraph's list of filters.
*
* @param filter the filter to free
*/
int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
+#if FF_API_AVFILTERBUFFER
/**
* Copy the frame properties of src to dst, without copying the actual
* image data.
*
* @return 0 on success, a negative number on error.
*/
+attribute_deprecated
int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
/**
*
* @return 0 on success, a negative number on error.
*/
+attribute_deprecated
int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src);
+#endif
+
+/**
+ * @return AVClass for AVFilterContext.
+ *
+ * @see av_opt_find().
+ */
+const AVClass *avfilter_get_class(void);
+
+typedef struct AVFilterGraphInternal AVFilterGraphInternal;
+
+typedef struct AVFilterGraph {
+ const AVClass *av_class;
+#if FF_API_FOO_COUNT
+ attribute_deprecated
+ unsigned filter_count;
+#endif
+ AVFilterContext **filters;
+#if !FF_API_FOO_COUNT
+ unsigned nb_filters;
+#endif
+
+ char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
+ char *resample_lavr_opts; ///< libavresample options to use for the auto-inserted resample filters
+#if FF_API_FOO_COUNT
+ unsigned nb_filters;
+#endif
+
+ /**
+ * Type of multithreading allowed for filters in this graph. A combination
+ * of AVFILTER_THREAD_* flags.
+ *
+ * May be set by the caller at any point, the setting will apply to all
+ * filters initialized after that. The default is allowing everything.
+ *
+ * When a filter in this graph is initialized, this field is combined using
+ * bit AND with AVFilterContext.thread_type to get the final mask used for
+ * determining allowed threading types. I.e. a threading type needs to be
+ * set in both to be allowed.
+ */
+ int thread_type;
+
+ /**
+ * Maximum number of threads used by filters in this graph. May be set by
+ * the caller before adding any filters to the filtergraph. Zero (the
+ * default) means that the number of threads is determined automatically.
+ */
+ int nb_threads;
+
+ /**
+ * Opaque object for libavfilter internal use.
+ */
+ AVFilterGraphInternal *internal;
+} AVFilterGraph;
+
+/**
+ * Allocate a filter graph.
+ */
+AVFilterGraph *avfilter_graph_alloc(void);
+
+/**
+ * Create a new filter instance in a filter graph.
+ *
+ * @param graph graph in which the new filter will be used
+ * @param filter the filter to create an instance of
+ * @param 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.
+ *
+ * @return 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.
+ */
+AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
+ const AVFilter *filter,
+ const char *name);
+
+/**
+ * Get a filter instance with name name from graph.
+ *
+ * @return the pointer to the found filter instance or NULL if it
+ * cannot be found.
+ */
+AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name);
+
+#if FF_API_AVFILTER_OPEN
+/**
+ * Add an existing filter instance to a filter graph.
+ *
+ * @param graphctx the filter graph
+ * @param filter the filter to be added
+ *
+ * @deprecated use avfilter_graph_alloc_filter() to allocate a filter in a
+ * filter graph
+ */
+attribute_deprecated
+int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
+#endif
+
+/**
+ * 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.
+ *
+ * @param name the instance name to give to the created filter instance
+ * @param graph_ctx the filter graph
+ * @return a negative AVERROR error code in case of failure, a non
+ * negative value otherwise
+ */
+int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
+ const char *name, const char *args, void *opaque,
+ AVFilterGraph *graph_ctx);
+
+/**
+ * Check validity and configure all the links and formats in the graph.
+ *
+ * @param graphctx the filter graph
+ * @param log_ctx context used for logging
+ * @return 0 in case of success, a negative AVERROR code otherwise
+ */
+int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
+
+/**
+ * Free a graph, destroy its links, and set *graph to NULL.
+ * If *graph is NULL, do nothing.
+ */
+void avfilter_graph_free(AVFilterGraph **graph);
+
+/**
+ * A linked-list of the inputs/outputs of the filter chain.
+ *
+ * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
+ * where it is used to communicate open (unlinked) inputs and outputs from and
+ * to the caller.
+ * This struct specifies, per each not connected pad contained in the graph, the
+ * filter context and the pad index required for establishing a link.
+ */
+typedef struct AVFilterInOut {
+ /** unique name for this input/output in the list */
+ char *name;
+
+ /** filter context associated to this input/output */
+ AVFilterContext *filter_ctx;
+
+ /** index of the filt_ctx pad to use for linking */
+ int pad_idx;
+
+ /** next input/input in the list, NULL if this is the last */
+ struct AVFilterInOut *next;
+} AVFilterInOut;
+
+/**
+ * Allocate a single AVFilterInOut entry.
+ * Must be freed with avfilter_inout_free().
+ * @return allocated AVFilterInOut on success, NULL on failure.
+ */
+AVFilterInOut *avfilter_inout_alloc(void);
+
+/**
+ * Free the supplied list of AVFilterInOut and set *inout to NULL.
+ * If *inout is NULL, do nothing.
+ */
+void avfilter_inout_free(AVFilterInOut **inout);
+
+/**
+ * Add a graph described by a string to a graph.
+ *
+ * @param graph the filter graph where to link the parsed graph context
+ * @param filters string to be parsed
+ * @param inputs linked list to the inputs of the graph
+ * @param outputs linked list to the outputs of the graph
+ * @return zero on success, a negative AVERROR code on error
+ */
+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.
+ *
+ * @param[in] graph the filter graph where to link the parsed graph context
+ * @param[in] filters string to be parsed
+ * @param[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().
+ * @param[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().
+ * @return zero on success, a negative AVERROR code on error
+ *
+ * @note the difference between avfilter_graph_parse2() and
+ * avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
+ * the lists of inputs and outputs, which therefore must be known before calling
+ * the function. On the other hand, avfilter_graph_parse2() \em returns the
+ * inputs and outputs that are left unlinked after parsing the graph and the
+ * caller then deals with them. Another difference is that in
+ * avfilter_graph_parse(), the inputs parameter describes inputs of the
+ * <em>already existing</em> 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.
+ * avfilter_graph_parse2() takes the opposite approach -- it 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.
+ */
+int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
+ AVFilterInOut **inputs,
+ AVFilterInOut **outputs);
+
+/**
+ * @}
+ */
#endif /* AVFILTER_AVFILTER_H */