/*

  * filter layer

  * Copyright (c) 2007 Bobby Bingham

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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.
  *
  * FFmpeg 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 FFmpeg; 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

 #include "libavutil/avutil.h"

 #include "libavutil/log.h"

 #include "libavutil/samplefmt.h"

 #include "libavutil/pixfmt.h"

 #include "libavutil/rational.h"

 #include "libavcodec/avcodec.h"

 #ifndef FF_API_OLD_VSINK_API

 #define FF_API_OLD_VSINK_API        (LIBAVFILTER_VERSION_MAJOR < 3)

 #endif

 #ifndef FF_API_OLD_ALL_FORMATS_API

 #define FF_API_OLD_ALL_FORMATS_API (LIBAVFILTER_VERSION_MAJOR < 3)

 #endif

 #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;
 
 /**

  * 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
     int linesize[8];            ///< number of bytes per line

     unsigned refcount;          ///< number of references to this buffer

 
     /** 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

 } 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

 #define AV_PERM_ALIGN    0x40   ///< the buffer must be aligned

 #define AVFILTER_ALIGN 16 //not part of ABI
 

 /**

  * 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 per channel

     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 sample_aspect_ratio; ///< sample 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

     int linesize[8];            ///< number of bytes per line

     int format;                 ///< media format

     /**
      * 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 perms;                  ///< permissions, see the AV_PERM_* flags

     enum AVMediaType type;      ///< media type of buffer data
     AVFilterBufferRefVideoProps *video; ///< video buffer specific properties

     AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties

 } AVFilterBufferRef;

 
 /**

  * Copy properties of src to dst, without copying the actual data

  */

 static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)

 {

     // copy common properties

     dst->pts             = src->pts;
     dst->pos             = src->pos;

 
     switch (src->type) {
     case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;

     case AVMEDIA_TYPE_AUDIO: *dst->audio = *src->audio; break;

     default: break;

     }

 }
 
 /**

  * 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

  */

 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

  */

 void avfilter_unref_buffer(AVFilterBufferRef *ref);

 /**

  * A list of supported formats for one end of a filter link. This is used
  * during the format negotiation process to try to pick the best format to
  * use to minimize the number of necessary conversions. Each filter gives a
  * list of the formats supported by each input and output pad. The list
  * given for each pad need not be distinct - they may be references to the
  * same list of formats, as is often the case when a filter supports multiple

  * formats, but will always output the same format as it is given in input.

  *
  * In this way, a list of possible input formats and a list of possible
  * output formats are associated with each link. When a set of formats is
  * negotiated over a link, the input and output lists are merged to form a
  * new list containing only the common elements of each list. In the case
  * that there were no common elements, a format conversion is necessary.
  * Otherwise, the lists are merged, and all other links which reference
  * either of the format lists involved in the merge are also affected.
  *
  * For example, consider the filter chain:
  * filter (a) --> (b) filter (b) --> (c) filter
  *
  * where the letters in parenthesis indicate a list of formats supported on
  * the input or output of the link. Suppose the lists are as follows:
  * (a) = {A, B}
  * (b) = {A, B, C}
  * (c) = {B, C}
  *
  * First, the first link's lists are merged, yielding:
  * filter (a) --> (a) filter (a) --> (c) filter
  *
  * Notice that format list (b) now refers to the same list as filter list (a).
  * Next, the lists for the second link are merged, yielding:
  * filter (a) --> (a) filter (a) --> (a) filter
  *
  * where (a) = {B}.
  *
  * Unfortunately, when the format lists at the two ends of a link are merged,
  * we must ensure that all links which reference either pre-merge format list
  * get updated as well. Therefore, we have the format list structure store a
  * pointer to each of the pointers to itself.
  */

 typedef struct AVFilterFormats {

     unsigned format_count;      ///< number of formats

     int64_t *formats;           ///< list of media formats

 
     unsigned refcount;          ///< number of references to this list

     struct AVFilterFormats ***refs; ///< references to this list

 }  AVFilterFormats;

 
 /**

  * Create a list of supported formats. This is intended for use in

  * AVFilter->query_formats().

  *

  * @param fmts list of media formats, terminated by -1. If NULL an
  *        empty list is created.

  * @return the format list, with no existing references
  */

 AVFilterFormats *avfilter_make_format_list(const int *fmts);

 AVFilterFormats *avfilter_make_format64_list(const int64_t *fmts);

 
 /**

  * Add fmt to the list of media formats contained in *avff.

  * If *avff is NULL the function allocates the filter formats struct
  * and puts its pointer in *avff.

  *
  * @return a non negative value in case of success, or a negative
  * value corresponding to an AVERROR code in case of error
  */

 int avfilter_add_format(AVFilterFormats **avff, int64_t fmt);

 #if FF_API_OLD_ALL_FORMATS_API

 /**

  * @deprecated Use avfilter_make_all_formats() instead.

  */

 attribute_deprecated

 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);

 #endif
 
 /**
  * Return a list of all formats supported by FFmpeg for the given media type.
  */
 AVFilterFormats *avfilter_make_all_formats(enum AVMediaType type);

 
 /**

  * A list of all channel layouts supported by libavfilter.
  */
 extern const int64_t avfilter_all_channel_layouts[];
 
 /**

  * Return a list of all channel layouts supported by FFmpeg.
  */

 AVFilterFormats *avfilter_make_all_channel_layouts(void);

 
 /**

  * Return a list of all audio packing formats.
  */

 AVFilterFormats *avfilter_make_all_packing_formats(void);

 
 /**

  * Return a format list which contains the intersection of the formats of

  * a and b. Also, all the references of a, all the references of b, and
  * a and b themselves will be deallocated.

  *
  * If a and b do not share any common formats, neither is modified, and NULL
  * is returned.
  */
 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
 

 /**

  * Add *ref as a new reference to formats.

  * That is the pointers will point like in the ASCII art below:

  *   ________

  *  |formats |<--------.
  *  |  ____  |     ____|___________________
  *  | |refs| |    |  __|_
  *  | |* * | |    | |  | |  AVFilterLink

  *  | |* *--------->|*ref|

  *  | |____| |    | |____|
  *  |________|    |________________________

  */

 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);

 
 /**

  * If *ref is non-NULL, remove *ref as a reference to the format list

  * it currently points to, deallocates that list if this was the last
  * reference, and sets *ref to NULL.

  *
  *         Before                                 After
  *   ________                               ________         NULL
  *  |formats |<--------.                   |formats |         ^
  *  |  ____  |     ____|________________   |  ____  |     ____|________________
  *  | |refs| |    |  __|_                  | |refs| |    |  __|_
  *  | |* * | |    | |  | |  AVFilterLink   | |* * | |    | |  | |  AVFilterLink
  *  | |* *--------->|*ref|                 | |*   | |    | |*ref|
  *  | |____| |    | |____|                 | |____| |    | |____|
  *  |________|    |_____________________   |________|    |_____________________

  */
 void avfilter_formats_unref(AVFilterFormats **ref);
 

 /**
  *
  *         Before                                 After
  *   ________                         ________

  *  |formats |<---------.            |formats |<---------.

  *  |  ____  |       ___|___         |  ____  |       ___|___
  *  | |refs| |      |   |   |        | |refs| |      |   |   |   NULL
  *  | |* *--------->|*oldref|        | |* *--------->|*newref|     ^
  *  | |* * | |      |_______|        | |* * | |      |_______|  ___|___
  *  | |____| |                       | |____| |                |   |   |
  *  |________|                       |________|                |*oldref|
  *                                                             |_______|
  */

 void avfilter_formats_changeref(AVFilterFormats **oldref,
                                 AVFilterFormats **newref);
 

 /**

  * A filter pad used for either input or output.

  */

 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. Can be AVMEDIA_TYPE_VIDEO or AVMEDIA_TYPE_AUDIO.

      */

     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.
      */
     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.
      */
     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.

      */

     void (*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.

      */

     AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, 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.
      */

     AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms, 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.

      */
     void (*end_frame)(AVFilterLink *link);
 
     /**

      * Slice drawing callback. This is where a filter receives video data

      * and should do its processing.
      *
      * Input video pads only.

      */

     void (*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.
      *
      * Input audio pads only.
      */
     void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
 
     /**

      * 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 video 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 video pads only.

      */

     int (*request_frame)(AVFilterLink *link);

 
     /**

      * Link configuration callback.
      *

      * For output pads, this should set the following link properties:
      * video: width, height, sample_aspect_ratio, time_base
      * audio: sample_rate.
      *
      * This should NOT set properties such as format, channel_layout, etc which
      * are 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 pads, this should return zero on success,

      * and another value on error.

      */

     int (*config_props)(AVFilterLink *link);

 };
 

 /** default handler for start_frame() for video inputs */

 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);

 /** default handler for draw_slice() for video inputs */

 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);

 /** default handler for end_frame() for video inputs */

 void avfilter_default_end_frame(AVFilterLink *link);

 /** default handler for filter_samples() for audio inputs */
 void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
 

 /** default handler for get_video_buffer() for video inputs */

 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,

                                                      int perms, int w, int h);

 
 /** default handler for get_audio_buffer() for audio inputs */

 AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link,
                                                      int perms, int nb_samples);

 /**

  * Helpers for query_formats() which set all links to the same list of
  * formats/layouts. If there are no links hooked to this filter, the list
  * of formats is freed.

  */

 void avfilter_set_common_pixel_formats(AVFilterContext *ctx, AVFilterFormats *formats);
 void avfilter_set_common_sample_formats(AVFilterContext *ctx, AVFilterFormats *formats);
 void avfilter_set_common_channel_layouts(AVFilterContext *ctx, AVFilterFormats *formats);

 void avfilter_set_common_packing_formats(AVFilterContext *ctx, AVFilterFormats *formats);

 /** Default handler for query_formats() */
 int avfilter_default_query_formats(AVFilterContext *ctx);

 /** start_frame() handler for filters which simply pass video along */

 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);

 
 /** draw_slice() handler for filters which simply pass video along */
 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
 
 /** end_frame() handler for filters which simply pass video along */
 void avfilter_null_end_frame(AVFilterLink *link);
 

 /** filter_samples() handler for filters which simply pass audio along */
 void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
 

 /** get_video_buffer() handler for filters which simply pass video along */

 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,

                                                   int perms, int w, int h);
 

 /** get_audio_buffer() handler for filters which simply pass audio along */

 AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link,
                                                   int perms, int nb_samples);

 /**

  * 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

     int priv_size;      ///< size of private data to allocate for the filter

     /**

      * Filter initialization function. Args contains the user-supplied
      * parameters. FIXME: maybe an AVOption-based system would be better?

      * opaque is data provided by the code requesting creation of the filter,
      * and is used to pass data to the filter.

      */

     int (*init)(AVFilterContext *ctx, const char *args, void *opaque);

 
     /**

      * 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/layouts supported by the filter and its pads, and sets
      * the in_formats/in_chlayouts for links connected to its output pads,
      * and out_formats/out_chlayouts for links connected to its input pads.

      *

      * @return zero on success, a negative value corresponding to an
      * AVERROR code otherwise

      */
     int (*query_formats)(AVFilterContext *);
 

     const AVFilterPad *inputs;  ///< NULL terminated list of inputs. NULL if none
     const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none

 
     /**
      * A description for the filter. You should use the
      * NULL_IF_CONFIG_SMALL() macro to define it.
      */
     const char *description;

 
     /**
      * Make the filter instance process a command.
      *
      * @param cmd    the command to process, for handling simplicity all commands must be alphanumeric only
      * @param arg    the argument for the command
      * @param res    a buffer with size res_size where the filter(s) can return a response. This must not change when the command is not supported.
      * @param flags  if AVFILTER_CMD_FLAG_FAST is set and the command would be

      *               time consuming then a filter should treat it like an unsupported command

      *
      * @returns >=0 on success otherwise an error code.
      *          AVERROR(ENOSYS) on unsupported commands
      */
     int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);

 } AVFilter;
 

 /** 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

     char *name;                     ///< name of this filter instance

     unsigned input_count;           ///< number of input pads
     AVFilterPad   *input_pads;      ///< array of input pads
     AVFilterLink **inputs;          ///< array of pointers to input links

     unsigned output_count;          ///< number of output pads
     AVFilterPad   *output_pads;     ///< array of output pads
     AVFilterLink **outputs;         ///< array of pointers to output links

     void *priv;                     ///< private data for use by the filter

 
     struct AVFilterCommand *command_queue;

 };
 

 enum AVFilterPacking {
     AVFILTER_PACKED = 0,
     AVFILTER_PLANAR,
 };
 

 /**

  * 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

     /** 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 w;                      ///< agreed upon image width
     int h;                      ///< agreed upon image height

     AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio

     /* These parameters apply only to audio */

     uint64_t channel_layout;    ///< channel layout of current buffer (see libavutil/audioconvert.h)

 #if LIBAVFILTER_VERSION_MAJOR < 3

     int64_t sample_rate;        ///< samples per second

 #else
     int sample_rate;            ///< samples per second
 #endif

     int planar;                 ///< agreed upon packing mode of audio buffers. true if planar.

     int format;                 ///< agreed upon media format

     /**

      * Lists of formats and channel layouts 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 and
      * channel_layout members, above, when chosen.
      *

      */
     AVFilterFormats *in_formats;
     AVFilterFormats *out_formats;
 

     AVFilterFormats *in_chlayouts;
     AVFilterFormats *out_chlayouts;

     AVFilterFormats *in_packing;
     AVFilterFormats *out_packing;

     /**

      * 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.
      * 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;

 
     struct AVFilterPool *pool;

 };
 

 /**

  * 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);
 

 /**

  * Free the link in *link, and set its pointer to NULL.
  */
 void avfilter_link_free(AVFilterLink **link);
 
 /**

  * 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);

 /**

  * Request a picture buffer with a specific set of permissions.

  *

  * @param link  the output link to the filter from which the buffer will

  *              be requested

  * @param perms the required access permissions

  * @param w     the minimum width of the buffer to allocate
  * @param h     the minimum height of the buffer to allocate

  * @return      A reference to the buffer. This must be unreferenced with
  *              avfilter_unref_buffer when you are finished with it.

  */

 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,

                                           int w, int h);

 
 /**

  * 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
  */
 AVFilterBufferRef *

 avfilter_get_video_buffer_ref_from_arrays(uint8_t * const data[4], const int linesize[4], int perms,

                                           int w, int h, enum PixelFormat format);
 
 /**

  * Request an audio samples buffer with a specific set of permissions.
  *
  * @param link           the output link to the filter from which the buffer will
  *                       be requested
  * @param perms          the required access permissions

  * @param nb_samples     the number of samples per channel

  * @return               A reference to the samples. This must be unreferenced with

  *                       avfilter_unref_buffer when you are finished with it.

  */
 AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,

                                              int nb_samples);

 
 /**

  * 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
  * @param planar         audio data layout - planar or packed
  */
 AVFilterBufferRef *
 avfilter_get_audio_buffer_ref_from_arrays(uint8_t *data[8], int linesize[8], int perms,
                                           int nb_samples, enum AVSampleFormat sample_fmt,

                                           uint64_t channel_layout, int planar);

 /**

  * Request an input frame from the filter at the other end of the link.

  *

  * @param link the input link
  * @return     zero on success

  */

 int avfilter_request_frame(AVFilterLink *link);

 
 /**

  * Poll a frame from the filter chain.

  *

  * @param  link the input link

  * @return the number of immediately available frames, a negative
  * number in case of error

  */
 int avfilter_poll_frame(AVFilterLink *link);
 
 /**

  * Notify the next filter of the start of a frame.

  *

  * @param link   the output link the frame will be sent over

  * @param picref A reference to the frame about to be sent. The data for this

  *               frame need only be valid once draw_slice() is called for that

  *               portion. The receiving filter will free this reference when

  *               it no longer needs it.
  */

 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);

 
 /**

  * Notify the next filter that the current frame has finished.

  *

  * @param link the output link the frame was sent over

  */

 void avfilter_end_frame(AVFilterLink *link);

 
 /**

  * Send a slice to the next filter.

  *
  * Slices have to be provided in sequential order, either in
  * top-bottom or bottom-top order. If slices are provided in
  * non-sequential order the behavior of the function is undefined.
  *

  * @param link the output link over which the frame is being sent
  * @param y    offset in pixels from the top of the image for this slice
  * @param h    height of this slice in pixels

  * @param slice_dir the assumed direction for sending slices,
  *             from the top slice to the bottom slice if the value is 1,
  *             from the bottom slice to the top slice if the value is -1,
  *             for other values the behavior of the function is undefined.

  */

 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);

 #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)
 
 /**
  * Make the filter instance process a command.

  * It is recommended to use avfilter_graph_send_command().

  */
 int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
 

 /**
  * Send a buffer of audio samples to the next filter.
  *
  * @param link       the output link over which the audio samples are being sent
  * @param samplesref a reference to the buffer of audio samples being sent. The
  *                   receiving filter will free this reference when it no longer
  *                   needs it or pass it on to the next filter.
  */
 void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
 

 /** Initialize the filter system. Register all built-in filters. */

 void avfilter_register_all(void);

 /** Uninitialize the filter system. Unregister all filters. */

 void avfilter_uninit(void);

 
 /**

  * 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.

  *

  * @param filter the filter to register

  * @return 0 if the registration was successful, 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);

 /**

  * 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.
  */
 AVFilter **av_filter_next(AVFilter **filter);
 
 /**

  * 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

  */

 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);

 
 /**

  * 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

  */

 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);

 
 /**

  * Free a filter context.

  *

  * @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);

 /**

  * Insert a new pad.

  *

  * @param idx Insertion point. Pad is inserted at the end if this point

  *            is beyond the end of the list of pads.
  * @param count Pointer to the number of pads in the list
  * @param padidx_off Offset within an AVFilterLink structure to the element
  *                   to increment when inserting a new pad causes link
  *                   numbering to change
  * @param pads Pointer to the pointer to the beginning of the list of pads
  * @param links Pointer to the pointer to the beginning of the list of links
  * @param newpad The new pad to add. A copy is made when adding.
  */
 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
                          AVFilterPad **pads, AVFilterLink ***links,
                          AVFilterPad *newpad);
 

 /** Insert a new input pad for the filter. */

 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
                                          AVFilterPad *p)
 {
     avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
                         &f->input_pads, &f->inputs, p);
 }
 

 /** Insert a new output pad for the filter. */

 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
                                           AVFilterPad *p)
 {
     avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
                         &f->output_pads, &f->outputs, p);
 }
 

 #endif /* AVFILTER_AVFILTER_H */