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ffmpeg/libavfilter/avfilter.h

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/*
* filter layer
* Copyright (c) 2007 Bobby Bingham
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#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/avutil.h"
#include "libavutil/frame.h"
#include "libavutil/log.h"
#include "libavutil/samplefmt.h"
#include "libavutil/pixfmt.h"
#include "libavutil/rational.h"
#include "libavcodec/avcodec.h"
#include <stddef.h>
#include "libavfilter/version.h"
/**
* Return the LIBAVFILTER_VERSION_INT constant.
*/
unsigned avfilter_version(void);
/**
* Return the libavfilter build-time configuration.
*/
const char *avfilter_configuration(void);
/**
* Return the libavfilter license.
*/
const char *avfilter_license(void);
typedef struct AVFilterContext AVFilterContext;
typedef struct AVFilterLink AVFilterLink;
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
* AVFilterBufferRef structure below.
*/
typedef struct AVFilterBuffer {
uint8_t *data[8]; ///< buffer data for each plane/channel
/**
* pointers to the data planes/channels.
*
* For video, this should simply point to data[].
*
* For planar audio, each channel has a separate data pointer, and
* linesize[0] contains the size of each channel buffer.
* For packed audio, there is just one data pointer, and linesize[0]
* contains the total size of the buffer for all channels.
*
* Note: Both data and extended_data will always be set, but for planar
* audio with more channels that can fit in data, extended_data must be used
* in order to access all channels.
*/
uint8_t **extended_data;
int linesize[8]; ///< number of bytes per line
/** private data to be used by a custom free function */
void *priv;
/**
* A pointer to the function to deallocate this buffer if the default
* function is not sufficient. This could, for example, add the memory
* back into a memory pool to be reused later without the overhead of
* reallocating it from scratch.
*/
void (*free)(struct AVFilterBuffer *buf);
int format; ///< media format
int w, h; ///< width and height of the allocated buffer
unsigned refcount; ///< number of references to this buffer
} AVFilterBuffer;
#define AV_PERM_READ 0x01 ///< can read from the buffer
#define AV_PERM_WRITE 0x02 ///< can write to the buffer
#define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
#define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
#define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
#define AV_PERM_NEG_LINESIZES 0x20 ///< the buffer requested can have negative linesizes
/**
* Audio specific properties in a reference to an AVFilterBuffer. Since
* AVFilterBufferRef is common to different media formats, audio specific
* per reference properties must be separated out.
*/
typedef struct AVFilterBufferRefAudioProps {
uint64_t channel_layout; ///< channel layout of audio buffer
int nb_samples; ///< number of audio samples
int sample_rate; ///< audio buffer sample rate
int planar; ///< audio buffer - planar or packed
} AVFilterBufferRefAudioProps;
/**
* Video specific properties in a reference to an AVFilterBuffer. Since
* AVFilterBufferRef is common to different media formats, video specific
* per reference properties must be separated out.
*/
typedef struct AVFilterBufferRefVideoProps {
int w; ///< image width
int h; ///< image height
AVRational pixel_aspect; ///< pixel aspect ratio
int interlaced; ///< is frame interlaced
int top_field_first; ///< field order
enum AVPictureType pict_type; ///< picture type of the frame
int key_frame; ///< 1 -> keyframe, 0-> not
} AVFilterBufferRefVideoProps;
/**
* A reference to an AVFilterBuffer. Since filters can manipulate the origin of
* a buffer to, for example, crop image without any memcpy, the buffer origin
* and dimensions are per-reference properties. Linesize is also useful for
* image flipping, frame to field filters, etc, and so is also per-reference.
*
* TODO: add anything necessary for frame reordering
*/
typedef struct AVFilterBufferRef {
AVFilterBuffer *buf; ///< the buffer that this is a reference to
uint8_t *data[8]; ///< picture/audio data for each plane
/**
* pointers to the data planes/channels.
*
* For video, this should simply point to data[].
*
* For planar audio, each channel has a separate data pointer, and
* linesize[0] contains the size of each channel buffer.
* For packed audio, there is just one data pointer, and linesize[0]
* contains the total size of the buffer for all channels.
*
* Note: Both data and extended_data will always be set, but for planar
* audio with more channels that can fit in data, extended_data must be used
* in order to access all channels.
*/
uint8_t **extended_data;
int linesize[8]; ///< number of bytes per line
AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
/**
* presentation timestamp. The time unit may change during
* filtering, as it is specified in the link and the filter code
* may need to rescale the PTS accordingly.
*/
int64_t pts;
int64_t pos; ///< byte position in stream, -1 if unknown
int format; ///< media format
int perms; ///< permissions, see the AV_PERM_* flags
enum AVMediaType type; ///< media type of buffer data
} AVFilterBufferRef;
/**
* Copy properties of src to dst, without copying the actual data
*/
attribute_deprecated
void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src);
/**
* Add a new reference to a buffer.
*
* @param ref an existing reference to the buffer
* @param pmask a bitmask containing the allowable permissions in the new
* reference
* @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);
/**
* Remove a reference to a buffer. If this is the last reference to the
* 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.
*
* @warning this struct will be removed from public API.
* users should call avfilter_pad_get_name() and avfilter_pad_get_type()
* to access the name and type fields; there should be no need to access
* any other fields from outside of libavfilter.
*/
struct AVFilterPad {
/**
* Pad name. The name is unique among inputs and among outputs, but an
* input may have the same name as an output. This may be NULL if this
* pad has no need to ever be referenced by name.
*/
const char *name;
/**
* AVFilterPad type.
*/
enum AVMediaType type;
/**
* Minimum required permissions on incoming buffers. Any buffer with
* insufficient permissions will be automatically copied by the filter
* system to a new buffer which provides the needed access permissions.
*
* Input pads only.
*/
attribute_deprecated int min_perms;
/**
* Permissions which are not accepted on incoming buffers. Any buffer
* which has any of these permissions set will be automatically copied
* by the filter system to a new buffer which does not have those
* permissions. This can be used to easily disallow buffers with
* AV_PERM_REUSE.
*
* Input pads only.
*/
attribute_deprecated int rej_perms;
/**
* @deprecated unused
*/
int (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
/**
* Callback function to get a video buffer. If NULL, the filter system will
* use avfilter_default_get_video_buffer().
*
* Input video pads only.
*/
AVFrame *(*get_video_buffer)(AVFilterLink *link, int w, int h);
/**
* Callback function to get an audio buffer. If NULL, the filter system will
* use avfilter_default_get_audio_buffer().
*
* Input audio pads only.
*/
AVFrame *(*get_audio_buffer)(AVFilterLink *link, int nb_samples);
/**
* @deprecated unused
*/
int (*end_frame)(AVFilterLink *link);
/**
* @deprecated unused
*/
int (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
/**
* Filtering callback. This is where a filter receives a frame with
* audio/video data and should do its processing.
*
* 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.
*/
int (*filter_frame)(AVFilterLink *link, AVFrame *frame);
/**
* Frame poll callback. This returns the number of immediately available
* samples. It should return a positive value if the next request_frame()
* is guaranteed to return one frame (with no delay).
*
* Defaults to just calling the source poll_frame() method.
*
* Output pads only.
*/
int (*poll_frame)(AVFilterLink *link);
/**
* Frame request callback. A call to this should result in at least one
* frame being output over the given link. This should return zero on
* success, and another value on error.
*
* Output pads only.
*/
int (*request_frame)(AVFilterLink *link);
/**
* Link configuration callback.
*
* For output pads, this should set the link properties such as
* width/height. This should NOT set the format property - that is
* negotiated between filters by the filter system using the
* query_formats() callback before this function is called.
*
* For input pads, this should check the properties of the link, and update
* the filter's internal state as necessary.
*
* For both input and output filters, this should return zero on success,
* and another value on error.
*/
int (*config_props)(AVFilterLink *link);
/**
* The filter expects a fifo to be inserted on its input link,
* typically because it has a delay.
*
* 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.
*
* @param pads an array of AVFilterPads
* @param pad_idx index of the pad in the array it; is the caller's
* responsibility to ensure the index is valid
*
* @return name of the pad_idx'th pad in pads
*/
const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
/**
* Get the type of an AVFilterPad.
*
* @param pads an array of AVFilterPads
* @param pad_idx index of the pad in the array; it is the caller's
* responsibility to ensure the index is valid
*
* @return type of the pad_idx'th pad in pads
*/
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)
/**
* 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
/**
* A description for the filter. 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
/**
* A class for the private data, used to access filter private
* AVOptions.
*/
const AVClass *priv_class;
/**
* A combination of AVFILTER_FLAG_*
*/
int flags;
/*****************************************************************
* All fields below this line are not part of the public API. They
* may not be used outside of libavfilter and can be changed and
* removed at will.
* New public fields should be added right above.
*****************************************************************
*/
/**
* Filter initialization function. Called when all the options have been
* set.
*/
int (*init)(AVFilterContext *ctx);
/**
* Should be set instead of init by the filters that want to pass a
* dictionary of AVOptions to nested contexts that are allocated in
* init.
*/
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.
*/
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.
*
* @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
struct AVFilter *next;
} AVFilter;
/** An instance of a filter */
struct AVFilterContext {
const AVClass *av_class; ///< needed for av_log()
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
#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
#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
};
/**
* A link between two filters. This contains pointers to the source and
* destination filters between which this link exists, and the indexes of
* the pads involved. In addition, this link also contains the parameters
* which have been negotiated and agreed upon between the filter, such as
* image dimensions, format, etc.
*/
struct AVFilterLink {
AVFilterContext *src; ///< source filter
AVFilterPad *srcpad; ///< output pad on the source filter
AVFilterContext *dst; ///< dest filter
AVFilterPad *dstpad; ///< input pad on the dest filter
enum AVMediaType type; ///< filter media type
/* These parameters apply only to video */
int w; ///< agreed upon image width
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/channel_layout.h)
int sample_rate; ///< samples per second
int format; ///< agreed upon media format
/**
* Define the time base used by the PTS of the frames/samples
* which will pass through this link.
* During the configuration stage, each filter is supposed to
* change only the output timebase, while the timebase of the
* input link is assumed to be an unchangeable property.
*/
AVRational time_base;
/*****************************************************************
* All fields below this line are not part of the public API. They
* may not be used outside of libavfilter and can be changed and
* removed at will.
* 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.
*/
AVFilterFormats *in_samplerates;
AVFilterFormats *out_samplerates;
struct AVFilterChannelLayouts *in_channel_layouts;
struct AVFilterChannelLayouts *out_channel_layouts;
/**
* Audio only, the destination filter sets this to a non-zero value to
* request that buffers with the given number of samples should be sent to
* it. AVFilterPad.needs_fifo must also be set on the corresponding input
* pad.
* 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;
};
/**
* Link two filters together.
*
* @param src the source filter
* @param srcpad index of the output pad on the source filter
* @param dst the destination filter
* @param dstpad index of the input pad on the destination filter
* @return zero on success
*/
int avfilter_link(AVFilterContext *src, unsigned srcpad,
AVFilterContext *dst, unsigned dstpad);
/**
* Negotiate the media format, dimensions, etc of all inputs to a filter.
*
* @param filter the filter to negotiate the properties for its inputs
* @return zero on successful negotiation
*/
int avfilter_config_links(AVFilterContext *filter);
#if FF_API_AVFILTERBUFFER
/**
* Create a buffer reference wrapped around an already allocated image
* buffer.
*
* @param data pointers to the planes of the image to reference
* @param linesize linesizes for the planes of the image to reference
* @param perms the required access permissions
* @param w the width of the image specified by the data and linesize arrays
* @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 AVPixelFormat format);
/**
* Create an audio buffer reference wrapped around an already
* allocated samples buffer.
*
* @param data pointers to the samples plane buffers
* @param linesize linesize for the samples plane buffers
* @param perms the required access permissions
* @param nb_samples number of samples per channel
* @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_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
* otherwise
*/
int avfilter_register(AVFilter *filter);
/**
* Get a filter definition matching the given name.
*
* @param name the filter name to find
* @return the filter definition, if any matching one is registered.
* NULL if none found.
*/
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_ctx put here a pointer to the created filter context
* on success, NULL on failure
* @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.
*
* @param filter the filter to initialize
* @param args A string of parameters to use when initializing the filter.
* The format and meaning of this string varies by filter.
* @param opaque Any extra non-string data needed by the filter. The meaning
* 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. This will also remove the filter from its
* filtergraph's list of filters.
*
* @param filter the filter to free
*/
void avfilter_free(AVFilterContext *filter);
/**
* Insert a filter in the middle of an existing link.
*
* @param link the link into which the filter should be inserted
* @param filt the filter to be inserted
* @param filt_srcpad_idx the input pad on the filter to connect
* @param filt_dstpad_idx the output pad on the filter to connect
* @return zero on success
*/
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);
/**
* Copy the frame properties and data pointers of src to dst, without copying
* the actual data.
*
* @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 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
} 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, 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 */
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