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/*
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 * filter layer
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 * Copyright (c) 2007 Bobby Bingham
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#ifndef AVFILTER_AVFILTER_H
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#define AVFILTER_AVFILTER_H
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#include "libavutil/avutil.h"
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#include "libavutil/samplefmt.h"
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#define LIBAVFILTER_VERSION_MAJOR  2
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#define LIBAVFILTER_VERSION_MINOR  4
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#define LIBAVFILTER_VERSION_MICRO  0
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#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
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                                               LIBAVFILTER_VERSION_MINOR, \
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                                               LIBAVFILTER_VERSION_MICRO)
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#define LIBAVFILTER_VERSION     AV_VERSION(LIBAVFILTER_VERSION_MAJOR,   \
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                                           LIBAVFILTER_VERSION_MINOR,   \
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                                           LIBAVFILTER_VERSION_MICRO)
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#define LIBAVFILTER_BUILD       LIBAVFILTER_VERSION_INT
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#include <stddef.h>
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/**
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 * Return the LIBAVFILTER_VERSION_INT constant.
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 */
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unsigned avfilter_version(void);
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/**
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 * Return the libavfilter build-time configuration.
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 */
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const char *avfilter_configuration(void);
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/**
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 * Return the libavfilter license.
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 */
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const char *avfilter_license(void);
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typedef struct AVFilterContext AVFilterContext;
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typedef struct AVFilterLink    AVFilterLink;
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typedef struct AVFilterPad     AVFilterPad;
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/**
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 * A reference-counted buffer data type used by the filter system. Filters
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 * should not store pointers to this structure directly, but instead use the
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 * AVFilterBufferRef structure below.
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 */
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typedef struct AVFilterBuffer {
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    uint8_t *data[8];           ///< buffer data for each plane/channel
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    int linesize[8];            ///< number of bytes per line
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    unsigned refcount;          ///< number of references to this buffer
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    /** private data to be used by a custom free function */
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    void *priv;
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    /**
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     * A pointer to the function to deallocate this buffer if the default
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     * function is not sufficient. This could, for example, add the memory
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     * back into a memory pool to be reused later without the overhead of
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     * reallocating it from scratch.
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     */
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    void (*free)(struct AVFilterBuffer *buf);
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    int format;                 ///< media format
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    int w, h;                   ///< width and height of the allocated buffer
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} AVFilterBuffer;
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#define AV_PERM_READ     0x01   ///< can read from the buffer
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#define AV_PERM_WRITE    0x02   ///< can write to the buffer
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#define AV_PERM_PRESERVE 0x04   ///< nobody else can overwrite the buffer
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#define AV_PERM_REUSE    0x08   ///< can output the buffer multiple times, with the same contents each time
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#define AV_PERM_REUSE2   0x10   ///< can output the buffer multiple times, modified each time
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#define AV_PERM_NEG_LINESIZES 0x20  ///< the buffer requested can have negative linesizes
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/**
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 * Audio specific properties in a reference to an AVFilterBuffer. Since
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 * AVFilterBufferRef is common to different media formats, audio specific
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 * per reference properties must be separated out.
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 */
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typedef struct AVFilterBufferRefAudioProps {
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    int64_t channel_layout;     ///< channel layout of audio buffer
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    int nb_samples;             ///< number of audio samples
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    int size;                   ///< audio buffer size
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    uint32_t sample_rate;       ///< audio buffer sample rate
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    int planar;                 ///< audio buffer - planar or packed
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} AVFilterBufferRefAudioProps;
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/**
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 * Video specific properties in a reference to an AVFilterBuffer. Since
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 * AVFilterBufferRef is common to different media formats, video specific
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 * per reference properties must be separated out.
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 */
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typedef struct AVFilterBufferRefVideoProps {
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    int w;                      ///< image width
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    int h;                      ///< image height
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    AVRational pixel_aspect;    ///< pixel aspect ratio
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    int interlaced;             ///< is frame interlaced
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    int top_field_first;        ///< field order
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    enum AVPictureType pict_type; ///< picture type of the frame
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    int key_frame;              ///< 1 -> keyframe, 0-> not
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} AVFilterBufferRefVideoProps;
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/**
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 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
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 * a buffer to, for example, crop image without any memcpy, the buffer origin
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 * and dimensions are per-reference properties. Linesize is also useful for
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 * image flipping, frame to field filters, etc, and so is also per-reference.
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 *
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 * TODO: add anything necessary for frame reordering
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 */
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typedef struct AVFilterBufferRef {
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    AVFilterBuffer *buf;        ///< the buffer that this is a reference to
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    uint8_t *data[8];           ///< picture/audio data for each plane
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    int linesize[8];            ///< number of bytes per line
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    int format;                 ///< media format
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    /**
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     * presentation timestamp. The time unit may change during
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     * filtering, as it is specified in the link and the filter code
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     * may need to rescale the PTS accordingly.
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     */
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    int64_t pts;
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    int64_t pos;                ///< byte position in stream, -1 if unknown
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    int perms;                  ///< permissions, see the AV_PERM_* flags
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    enum AVMediaType type;      ///< media type of buffer data
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    AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
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    AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
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} AVFilterBufferRef;
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/**
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 * Copy properties of src to dst, without copying the actual data
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 */
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static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
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{
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    // copy common properties
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    dst->pts             = src->pts;
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    dst->pos             = src->pos;
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    switch (src->type) {
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    case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
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    case AVMEDIA_TYPE_AUDIO: *dst->audio = *src->audio; break;
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    }
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}
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/**
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 * Add a new reference to a buffer.
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 *
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 * @param ref   an existing reference to the buffer
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 * @param pmask a bitmask containing the allowable permissions in the new
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 *              reference
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 * @return      a new reference to the buffer with the same properties as the
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 *              old, excluding any permissions denied by pmask
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 */
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AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
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/**
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 * Remove a reference to a buffer. If this is the last reference to the
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 * buffer, the buffer itself is also automatically freed.
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 *
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 * @param ref reference to the buffer, may be NULL
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 */
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void avfilter_unref_buffer(AVFilterBufferRef *ref);
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/**
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 * A list of supported formats for one end of a filter link. This is used
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 * during the format negotiation process to try to pick the best format to
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 * use to minimize the number of necessary conversions. Each filter gives a
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 * list of the formats supported by each input and output pad. The list
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 * given for each pad need not be distinct - they may be references to the
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 * same list of formats, as is often the case when a filter supports multiple
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 * formats, but will always output the same format as it is given in input.
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 *
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 * In this way, a list of possible input formats and a list of possible
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 * output formats are associated with each link. When a set of formats is
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 * negotiated over a link, the input and output lists are merged to form a
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 * new list containing only the common elements of each list. In the case
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 * that there were no common elements, a format conversion is necessary.
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 * Otherwise, the lists are merged, and all other links which reference
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 * either of the format lists involved in the merge are also affected.
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 *
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 * For example, consider the filter chain:
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 * filter (a) --> (b) filter (b) --> (c) filter
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 *
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 * where the letters in parenthesis indicate a list of formats supported on
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 * the input or output of the link. Suppose the lists are as follows:
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 * (a) = {A, B}
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 * (b) = {A, B, C}
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 * (c) = {B, C}
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 *
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 * First, the first link's lists are merged, yielding:
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 * filter (a) --> (a) filter (a) --> (c) filter
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 *
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 * Notice that format list (b) now refers to the same list as filter list (a).
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 * Next, the lists for the second link are merged, yielding:
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 * filter (a) --> (a) filter (a) --> (a) filter
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 *
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 * where (a) = {B}.
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 *
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 * Unfortunately, when the format lists at the two ends of a link are merged,
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 * we must ensure that all links which reference either pre-merge format list
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 * get updated as well. Therefore, we have the format list structure store a
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 * pointer to each of the pointers to itself.
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 */
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typedef struct AVFilterFormats {
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    unsigned format_count;      ///< number of formats
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    int *formats;               ///< list of media formats
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    unsigned refcount;          ///< number of references to this list
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    struct AVFilterFormats ***refs; ///< references to this list
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}  AVFilterFormats;
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/**
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 * Create a list of supported formats. This is intended for use in
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 * AVFilter->query_formats().
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 *
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 * @param fmts list of media formats, terminated by -1
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 * @return the format list, with no existing references
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 */
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AVFilterFormats *avfilter_make_format_list(const int *fmts);
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/**
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 * Add fmt to the list of media formats contained in *avff.
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 * If *avff is NULL the function allocates the filter formats struct
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 * and puts its pointer in *avff.
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 *
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 * @return a non negative value in case of success, or a negative
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 * value corresponding to an AVERROR code in case of error
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 */
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int avfilter_add_format(AVFilterFormats **avff, int fmt);
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/**
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 * Return a list of all formats supported by Libav for the given media type.
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 */
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AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
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/**
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 * Return a format list which contains the intersection of the formats of
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 * a and b. Also, all the references of a, all the references of b, and
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 * a and b themselves will be deallocated.
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 *
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 * If a and b do not share any common formats, neither is modified, and NULL
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 * is returned.
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 */
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AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
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/**
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 * Add *ref as a new reference to formats.
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 * That is the pointers will point like in the ascii art below:
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 *   ________
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 *  |formats |<--------.
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 *  |  ____  |     ____|___________________
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 *  | |refs| |    |  __|_
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 *  | |* * | |    | |  | |  AVFilterLink
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 *  | |* *--------->|*ref|
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 *  | |____| |    | |____|
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 *  |________|    |________________________
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 */
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void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
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/**
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 * If *ref is non-NULL, remove *ref as a reference to the format list
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 * it currently points to, deallocates that list if this was the last
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 * reference, and sets *ref to NULL.
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 *
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 *         Before                                 After
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 *   ________                               ________         NULL
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 *  |formats |<--------.                   |formats |         ^
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 *  |  ____  |     ____|________________   |  ____  |     ____|________________
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 *  | |refs| |    |  __|_                  | |refs| |    |  __|_
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 *  | |* * | |    | |  | |  AVFilterLink   | |* * | |    | |  | |  AVFilterLink
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 *  | |* *--------->|*ref|                 | |*   | |    | |*ref|
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 *  | |____| |    | |____|                 | |____| |    | |____|
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 *  |________|    |_____________________   |________|    |_____________________
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 */
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void avfilter_formats_unref(AVFilterFormats **ref);
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/**
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 *
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 *         Before                                 After
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 *   ________                         ________
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 *  |formats |<---------.            |formats |<---------.
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 *  |  ____  |       ___|___         |  ____  |       ___|___
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 *  | |refs| |      |   |   |        | |refs| |      |   |   |   NULL
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 *  | |* *--------->|*oldref|        | |* *--------->|*newref|     ^
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 *  | |* * | |      |_______|        | |* * | |      |_______|  ___|___
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 *  | |____| |                       | |____| |                |   |   |
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 *  |________|                       |________|                |*oldref|
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 *                                                             |_______|
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 */
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void avfilter_formats_changeref(AVFilterFormats **oldref,
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                                AVFilterFormats **newref);
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/**
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 * A filter pad used for either input or output.
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 */
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struct AVFilterPad {
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    /**
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     * Pad name. The name is unique among inputs and among outputs, but an
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     * input may have the same name as an output. This may be NULL if this
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     * pad has no need to ever be referenced by name.
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     */
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    const char *name;
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    /**
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     * AVFilterPad type. Only video supported now, hopefully someone will
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     * add audio in the future.
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     */
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    enum AVMediaType type;
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    /**
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     * Minimum required permissions on incoming buffers. Any buffer with
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     * insufficient permissions will be automatically copied by the filter
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     * system to a new buffer which provides the needed access permissions.
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     *
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     * Input pads only.
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     */
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    int min_perms;
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    /**
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     * Permissions which are not accepted on incoming buffers. Any buffer
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     * which has any of these permissions set will be automatically copied
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     * by the filter system to a new buffer which does not have those
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     * permissions. This can be used to easily disallow buffers with
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     * AV_PERM_REUSE.
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     *
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     * Input pads only.
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     */
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    int rej_perms;
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    /**
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     * Callback called before passing the first slice of a new frame. If
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     * NULL, the filter layer will default to storing a reference to the
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     * picture inside the link structure.
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     *
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     * Input video pads only.
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     */
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    void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
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    /**
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     * Callback function to get a video buffer. If NULL, the filter system will
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     * use avfilter_default_get_video_buffer().
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     *
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     * Input video pads only.
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     */
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    AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
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    /**
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     * Callback function to get an audio buffer. If NULL, the filter system will
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     * use avfilter_default_get_audio_buffer().
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     *
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     * Input audio pads only.
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     */
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    AVFilterBufferRef *(*get_audio_buffer)(AVFilterLink *link, int perms,
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                                           enum AVSampleFormat sample_fmt, int size,
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                                           int64_t channel_layout, int planar);
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    /**
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     * Callback called after the slices of a frame are completely sent. If
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     * NULL, the filter layer will default to releasing the reference stored
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     * in the link structure during start_frame().
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     *
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     * Input video pads only.
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     */
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    void (*end_frame)(AVFilterLink *link);
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    /**
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     * Slice drawing callback. This is where a filter receives video data
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     * and should do its processing.
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     *
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     * Input video pads only.
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     */
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    void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
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    /**
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     * Samples filtering callback. This is where a filter receives audio data
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     * and should do its processing.
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     *
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     * Input audio pads only.
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     */
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    void (*filter_samples)(AVFilterLink *link, AVFilterBufferRef *samplesref);
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    /**
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     * Frame poll callback. This returns the number of immediately available
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     * samples. It should return a positive value if the next request_frame()
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     * is guaranteed to return one frame (with no delay).
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     *
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     * Defaults to just calling the source poll_frame() method.
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     *
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     * Output video pads only.
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     */
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    int (*poll_frame)(AVFilterLink *link);
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    /**
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     * Frame request callback. A call to this should result in at least one
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     * frame being output over the given link. This should return zero on
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     * success, and another value on error.
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     *
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     * Output video pads only.
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     */
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    int (*request_frame)(AVFilterLink *link);
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    /**
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     * Link configuration callback.
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     *
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     * For output pads, this should set the link properties such as
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     * width/height. This should NOT set the format property - that is
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     * negotiated between filters by the filter system using the
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     * query_formats() callback before this function is called.
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     *
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     * For input pads, this should check the properties of the link, and update
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     * the filter's internal state as necessary.
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     *
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     * For both input and output filters, this should return zero on success,
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     * and another value on error.
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     */
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    int (*config_props)(AVFilterLink *link);
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};
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/** default handler for start_frame() for video inputs */
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void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
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/** default handler for draw_slice() for video inputs */
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void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
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/** default handler for end_frame() for video inputs */
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void avfilter_default_end_frame(AVFilterLink *link);
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/** default handler for filter_samples() for audio inputs */
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void avfilter_default_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
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/** default handler for config_props() for audio/video outputs */
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int avfilter_default_config_output_link(AVFilterLink *link);
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/** default handler for config_props() for audio/video inputs */
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int avfilter_default_config_input_link (AVFilterLink *link);
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/** default handler for get_video_buffer() for video inputs */
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AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
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                                                     int perms, int w, int h);
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/** default handler for get_audio_buffer() for audio inputs */
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AVFilterBufferRef *avfilter_default_get_audio_buffer(AVFilterLink *link, int perms,
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                                                     enum AVSampleFormat sample_fmt, int size,
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                                                     int64_t channel_layout, int planar);
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/**
468
 * A helper for query_formats() which sets all links to the same list of
469
 * formats. If there are no links hooked to this filter, the list of formats is
470
 * freed.
471
 */
472
void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
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/** Default handler for query_formats() */
475
int avfilter_default_query_formats(AVFilterContext *ctx);
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/** start_frame() handler for filters which simply pass video along */
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void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
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/** draw_slice() handler for filters which simply pass video along */
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void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
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/** end_frame() handler for filters which simply pass video along */
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void avfilter_null_end_frame(AVFilterLink *link);
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/** filter_samples() handler for filters which simply pass audio along */
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void avfilter_null_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
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/** get_video_buffer() handler for filters which simply pass video along */
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AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
491
                                                  int perms, int w, int h);
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/** get_audio_buffer() handler for filters which simply pass audio along */
494
AVFilterBufferRef *avfilter_null_get_audio_buffer(AVFilterLink *link, int perms,
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                                                  enum AVSampleFormat sample_fmt, int size,
496
                                                  int64_t channel_layout, int planar);
497

    
498
/**
499
 * Filter definition. This defines the pads a filter contains, and all the
500
 * callback functions used to interact with the filter.
501
 */
502
typedef struct AVFilter {
503
    const char *name;         ///< filter name
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505
    int priv_size;      ///< size of private data to allocate for the filter
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507
    /**
508
     * Filter initialization function. Args contains the user-supplied
509
     * parameters. FIXME: maybe an AVOption-based system would be better?
510
     * opaque is data provided by the code requesting creation of the filter,
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     * and is used to pass data to the filter.
512
     */
513
    int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
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    /**
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     * Filter uninitialization function. Should deallocate any memory held
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     * by the filter, release any buffer references, etc. This does not need
518
     * to deallocate the AVFilterContext->priv memory itself.
519
     */
520
    void (*uninit)(AVFilterContext *ctx);
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522
    /**
523
     * Queries formats supported by the filter and its pads, and sets the
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     * in_formats for links connected to its output pads, and out_formats
525
     * for links connected to its input pads.
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     *
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     * @return zero on success, a negative value corresponding to an
528
     * AVERROR code otherwise
529
     */
530
    int (*query_formats)(AVFilterContext *);
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532
    const AVFilterPad *inputs;  ///< NULL terminated list of inputs. NULL if none
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    const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
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    /**
536
     * A description for the filter. You should use the
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     * NULL_IF_CONFIG_SMALL() macro to define it.
538
     */
539
    const char *description;
540
} AVFilter;
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/** An instance of a filter */
543
struct AVFilterContext {
544
    const AVClass *av_class;              ///< needed for av_log()
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    AVFilter *filter;               ///< the AVFilter of which this is an instance
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548
    char *name;                     ///< name of this filter instance
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550
    unsigned input_count;           ///< number of input pads
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    AVFilterPad   *input_pads;      ///< array of input pads
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    AVFilterLink **inputs;          ///< array of pointers to input links
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    unsigned output_count;          ///< number of output pads
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    AVFilterPad   *output_pads;     ///< array of output pads
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    AVFilterLink **outputs;         ///< array of pointers to output links
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    void *priv;                     ///< private data for use by the filter
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};
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/**
562
 * A link between two filters. This contains pointers to the source and
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 * destination filters between which this link exists, and the indexes of
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 * the pads involved. In addition, this link also contains the parameters
565
 * which have been negotiated and agreed upon between the filter, such as
566
 * image dimensions, format, etc.
567
 */
568
struct AVFilterLink {
569
    AVFilterContext *src;       ///< source filter
570
    AVFilterPad *srcpad;        ///< output pad on the source filter
571

    
572
    AVFilterContext *dst;       ///< dest filter
573
    AVFilterPad *dstpad;        ///< input pad on the dest filter
574

    
575
    /** stage of the initialization of the link properties (dimensions, etc) */
576
    enum {
577
        AVLINK_UNINIT = 0,      ///< not started
578
        AVLINK_STARTINIT,       ///< started, but incomplete
579
        AVLINK_INIT             ///< complete
580
    } init_state;
581

    
582
    enum AVMediaType type;      ///< filter media type
583

    
584
    /* These parameters apply only to video */
585
    int w;                      ///< agreed upon image width
586
    int h;                      ///< agreed upon image height
587
    AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
588
    /* These two parameters apply only to audio */
589
    int64_t channel_layout;     ///< channel layout of current buffer (see libavutil/audioconvert.h)
590
    int64_t sample_rate;        ///< samples per second
591

    
592
    int format;                 ///< agreed upon media format
593

    
594
    /**
595
     * Lists of formats supported by the input and output filters respectively.
596
     * These lists are used for negotiating the format to actually be used,
597
     * which will be loaded into the format member, above, when chosen.
598
     */
599
    AVFilterFormats *in_formats;
600
    AVFilterFormats *out_formats;
601

    
602
    /**
603
     * The buffer reference currently being sent across the link by the source
604
     * filter. This is used internally by the filter system to allow
605
     * automatic copying of buffers which do not have sufficient permissions
606
     * for the destination. This should not be accessed directly by the
607
     * filters.
608
     */
609
    AVFilterBufferRef *src_buf;
610

    
611
    AVFilterBufferRef *cur_buf;
612
    AVFilterBufferRef *out_buf;
613

    
614
    /**
615
     * Define the time base used by the PTS of the frames/samples
616
     * which will pass through this link.
617
     * During the configuration stage, each filter is supposed to
618
     * change only the output timebase, while the timebase of the
619
     * input link is assumed to be an unchangeable property.
620
     */
621
    AVRational time_base;
622
};
623

    
624
/**
625
 * Link two filters together.
626
 *
627
 * @param src    the source filter
628
 * @param srcpad index of the output pad on the source filter
629
 * @param dst    the destination filter
630
 * @param dstpad index of the input pad on the destination filter
631
 * @return       zero on success
632
 */
633
int avfilter_link(AVFilterContext *src, unsigned srcpad,
634
                  AVFilterContext *dst, unsigned dstpad);
635

    
636
/**
637
 * Negotiate the media format, dimensions, etc of all inputs to a filter.
638
 *
639
 * @param filter the filter to negotiate the properties for its inputs
640
 * @return       zero on successful negotiation
641
 */
642
int avfilter_config_links(AVFilterContext *filter);
643

    
644
/**
645
 * Request a picture buffer with a specific set of permissions.
646
 *
647
 * @param link  the output link to the filter from which the buffer will
648
 *              be requested
649
 * @param perms the required access permissions
650
 * @param w     the minimum width of the buffer to allocate
651
 * @param h     the minimum height of the buffer to allocate
652
 * @return      A reference to the buffer. This must be unreferenced with
653
 *              avfilter_unref_buffer when you are finished with it.
654
 */
655
AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
656
                                          int w, int h);
657

    
658
/**
659
 * Create a buffer reference wrapped around an already allocated image
660
 * buffer.
661
 *
662
 * @param data pointers to the planes of the image to reference
663
 * @param linesize linesizes for the planes of the image to reference
664
 * @param perms the required access permissions
665
 * @param w the width of the image specified by the data and linesize arrays
666
 * @param h the height of the image specified by the data and linesize arrays
667
 * @param format the pixel format of the image specified by the data and linesize arrays
668
 */
669
AVFilterBufferRef *
670
avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int perms,
671
                                          int w, int h, enum PixelFormat format);
672

    
673
/**
674
 * Request an audio samples buffer with a specific set of permissions.
675
 *
676
 * @param link           the output link to the filter from which the buffer will
677
 *                       be requested
678
 * @param perms          the required access permissions
679
 * @param sample_fmt     the format of each sample in the buffer to allocate
680
 * @param size           the buffer size in bytes
681
 * @param channel_layout the number and type of channels per sample in the buffer to allocate
682
 * @param planar         audio data layout - planar or packed
683
 * @return               A reference to the samples. This must be unreferenced with
684
 *                       avfilter_unref_buffer when you are finished with it.
685
 */
686
AVFilterBufferRef *avfilter_get_audio_buffer(AVFilterLink *link, int perms,
687
                                             enum AVSampleFormat sample_fmt, int size,
688
                                             int64_t channel_layout, int planar);
689

    
690
/**
691
 * Request an input frame from the filter at the other end of the link.
692
 *
693
 * @param link the input link
694
 * @return     zero on success
695
 */
696
int avfilter_request_frame(AVFilterLink *link);
697

    
698
/**
699
 * Poll a frame from the filter chain.
700
 *
701
 * @param  link the input link
702
 * @return the number of immediately available frames, a negative
703
 * number in case of error
704
 */
705
int avfilter_poll_frame(AVFilterLink *link);
706

    
707
/**
708
 * Notifie the next filter of the start of a frame.
709
 *
710
 * @param link   the output link the frame will be sent over
711
 * @param picref A reference to the frame about to be sent. The data for this
712
 *               frame need only be valid once draw_slice() is called for that
713
 *               portion. The receiving filter will free this reference when
714
 *               it no longer needs it.
715
 */
716
void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
717

    
718
/**
719
 * Notifie the next filter that the current frame has finished.
720
 *
721
 * @param link the output link the frame was sent over
722
 */
723
void avfilter_end_frame(AVFilterLink *link);
724

    
725
/**
726
 * Send a slice to the next filter.
727
 *
728
 * Slices have to be provided in sequential order, either in
729
 * top-bottom or bottom-top order. If slices are provided in
730
 * non-sequential order the behavior of the function is undefined.
731
 *
732
 * @param link the output link over which the frame is being sent
733
 * @param y    offset in pixels from the top of the image for this slice
734
 * @param h    height of this slice in pixels
735
 * @param slice_dir the assumed direction for sending slices,
736
 *             from the top slice to the bottom slice if the value is 1,
737
 *             from the bottom slice to the top slice if the value is -1,
738
 *             for other values the behavior of the function is undefined.
739
 */
740
void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
741

    
742
/**
743
 * Send a buffer of audio samples to the next filter.
744
 *
745
 * @param link       the output link over which the audio samples are being sent
746
 * @param samplesref a reference to the buffer of audio samples being sent. The
747
 *                   receiving filter will free this reference when it no longer
748
 *                   needs it or pass it on to the next filter.
749
 */
750
void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref);
751

    
752
/** Initialize the filter system. Register all builtin filters. */
753
void avfilter_register_all(void);
754

    
755
/** Uninitialize the filter system. Unregister all filters. */
756
void avfilter_uninit(void);
757

    
758
/**
759
 * Register a filter. This is only needed if you plan to use
760
 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
761
 * filter can still by instantiated with avfilter_open even if it is not
762
 * registered.
763
 *
764
 * @param filter the filter to register
765
 * @return 0 if the registration was succesfull, a negative value
766
 * otherwise
767
 */
768
int avfilter_register(AVFilter *filter);
769

    
770
/**
771
 * Get a filter definition matching the given name.
772
 *
773
 * @param name the filter name to find
774
 * @return     the filter definition, if any matching one is registered.
775
 *             NULL if none found.
776
 */
777
AVFilter *avfilter_get_by_name(const char *name);
778

    
779
/**
780
 * If filter is NULL, returns a pointer to the first registered filter pointer,
781
 * if filter is non-NULL, returns the next pointer after filter.
782
 * If the returned pointer points to NULL, the last registered filter
783
 * was already reached.
784
 */
785
AVFilter **av_filter_next(AVFilter **filter);
786

    
787
/**
788
 * Create a filter instance.
789
 *
790
 * @param filter_ctx put here a pointer to the created filter context
791
 * on success, NULL on failure
792
 * @param filter    the filter to create an instance of
793
 * @param inst_name Name to give to the new instance. Can be NULL for none.
794
 * @return >= 0 in case of success, a negative error code otherwise
795
 */
796
int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
797

    
798
/**
799
 * Initialize a filter.
800
 *
801
 * @param filter the filter to initialize
802
 * @param args   A string of parameters to use when initializing the filter.
803
 *               The format and meaning of this string varies by filter.
804
 * @param opaque Any extra non-string data needed by the filter. The meaning
805
 *               of this parameter varies by filter.
806
 * @return       zero on success
807
 */
808
int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
809

    
810
/**
811
 * Free a filter context.
812
 *
813
 * @param filter the filter to free
814
 */
815
void avfilter_free(AVFilterContext *filter);
816

    
817
/**
818
 * Insert a filter in the middle of an existing link.
819
 *
820
 * @param link the link into which the filter should be inserted
821
 * @param filt the filter to be inserted
822
 * @param filt_srcpad_idx the input pad on the filter to connect
823
 * @param filt_dstpad_idx the output pad on the filter to connect
824
 * @return     zero on success
825
 */
826
int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
827
                           unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
828

    
829
/**
830
 * Insert a new pad.
831
 *
832
 * @param idx Insertion point. Pad is inserted at the end if this point
833
 *            is beyond the end of the list of pads.
834
 * @param count Pointer to the number of pads in the list
835
 * @param padidx_off Offset within an AVFilterLink structure to the element
836
 *                   to increment when inserting a new pad causes link
837
 *                   numbering to change
838
 * @param pads Pointer to the pointer to the beginning of the list of pads
839
 * @param links Pointer to the pointer to the beginning of the list of links
840
 * @param newpad The new pad to add. A copy is made when adding.
841
 */
842
void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
843
                         AVFilterPad **pads, AVFilterLink ***links,
844
                         AVFilterPad *newpad);
845

    
846
/** Insert a new input pad for the filter. */
847
static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
848
                                         AVFilterPad *p)
849
{
850
    avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
851
                        &f->input_pads, &f->inputs, p);
852
}
853

    
854
/** Insert a new output pad for the filter. */
855
static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
856
                                          AVFilterPad *p)
857
{
858
    avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
859
                        &f->output_pads, &f->outputs, p);
860
}
861

    
862
#endif  /* AVFILTER_AVFILTER_H */