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  1. /*
  2.  * filter layer
  3.  * Copyright (c) 2007 Bobby Bingham
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #ifndef AVFILTER_AVFILTER_H
  23. #define AVFILTER_AVFILTER_H
  24.  
  25. /**
  26.  * @file
  27.  * @ingroup lavfi
  28.  * Main libavfilter public API header
  29.  */
  30.  
  31. /**
  32.  * @defgroup lavfi Libavfilter - graph-based frame editing library
  33.  * @{
  34.  */
  35.  
  36. #include <stddef.h>
  37.  
  38. #include "libavutil/attributes.h"
  39. #include "libavutil/avutil.h"
  40. #include "libavutil/dict.h"
  41. #include "libavutil/frame.h"
  42. #include "libavutil/log.h"
  43. #include "libavutil/samplefmt.h"
  44. #include "libavutil/pixfmt.h"
  45. #include "libavutil/rational.h"
  46.  
  47. #include "libavfilter/version.h"
  48.  
  49. /**
  50.  * Return the LIBAVFILTER_VERSION_INT constant.
  51.  */
  52. unsigned avfilter_version(void);
  53.  
  54. /**
  55.  * Return the libavfilter build-time configuration.
  56.  */
  57. const char *avfilter_configuration(void);
  58.  
  59. /**
  60.  * Return the libavfilter license.
  61.  */
  62. const char *avfilter_license(void);
  63.  
  64. typedef struct AVFilterContext AVFilterContext;
  65. typedef struct AVFilterLink    AVFilterLink;
  66. typedef struct AVFilterPad     AVFilterPad;
  67. typedef struct AVFilterFormats AVFilterFormats;
  68.  
  69. #if FF_API_AVFILTERBUFFER
  70. /**
  71.  * A reference-counted buffer data type used by the filter system. Filters
  72.  * should not store pointers to this structure directly, but instead use the
  73.  * AVFilterBufferRef structure below.
  74.  */
  75. typedef struct AVFilterBuffer {
  76.     uint8_t *data[8];           ///< buffer data for each plane/channel
  77.  
  78.     /**
  79.      * pointers to the data planes/channels.
  80.      *
  81.      * For video, this should simply point to data[].
  82.      *
  83.      * For planar audio, each channel has a separate data pointer, and
  84.      * linesize[0] contains the size of each channel buffer.
  85.      * For packed audio, there is just one data pointer, and linesize[0]
  86.      * contains the total size of the buffer for all channels.
  87.      *
  88.      * Note: Both data and extended_data will always be set, but for planar
  89.      * audio with more channels that can fit in data, extended_data must be used
  90.      * in order to access all channels.
  91.      */
  92.     uint8_t **extended_data;
  93.     int linesize[8];            ///< number of bytes per line
  94.  
  95.     /** private data to be used by a custom free function */
  96.     void *priv;
  97.     /**
  98.      * A pointer to the function to deallocate this buffer if the default
  99.      * function is not sufficient. This could, for example, add the memory
  100.      * back into a memory pool to be reused later without the overhead of
  101.      * reallocating it from scratch.
  102.      */
  103.     void (*free)(struct AVFilterBuffer *buf);
  104.  
  105.     int format;                 ///< media format
  106.     int w, h;                   ///< width and height of the allocated buffer
  107.     unsigned refcount;          ///< number of references to this buffer
  108. } AVFilterBuffer;
  109.  
  110. #define AV_PERM_READ     0x01   ///< can read from the buffer
  111. #define AV_PERM_WRITE    0x02   ///< can write to the buffer
  112. #define AV_PERM_PRESERVE 0x04   ///< nobody else can overwrite the buffer
  113. #define AV_PERM_REUSE    0x08   ///< can output the buffer multiple times, with the same contents each time
  114. #define AV_PERM_REUSE2   0x10   ///< can output the buffer multiple times, modified each time
  115. #define AV_PERM_NEG_LINESIZES 0x20  ///< the buffer requested can have negative linesizes
  116. #define AV_PERM_ALIGN    0x40   ///< the buffer must be aligned
  117.  
  118. #define AVFILTER_ALIGN 16 //not part of ABI
  119.  
  120. /**
  121.  * Audio specific properties in a reference to an AVFilterBuffer. Since
  122.  * AVFilterBufferRef is common to different media formats, audio specific
  123.  * per reference properties must be separated out.
  124.  */
  125. typedef struct AVFilterBufferRefAudioProps {
  126.     uint64_t channel_layout;    ///< channel layout of audio buffer
  127.     int nb_samples;             ///< number of audio samples per channel
  128.     int sample_rate;            ///< audio buffer sample rate
  129.     int channels;               ///< number of channels (do not access directly)
  130. } AVFilterBufferRefAudioProps;
  131.  
  132. /**
  133.  * Video specific properties in a reference to an AVFilterBuffer. Since
  134.  * AVFilterBufferRef is common to different media formats, video specific
  135.  * per reference properties must be separated out.
  136.  */
  137. typedef struct AVFilterBufferRefVideoProps {
  138.     int w;                      ///< image width
  139.     int h;                      ///< image height
  140.     AVRational sample_aspect_ratio; ///< sample aspect ratio
  141.     int interlaced;             ///< is frame interlaced
  142.     int top_field_first;        ///< field order
  143.     enum AVPictureType pict_type; ///< picture type of the frame
  144.     int key_frame;              ///< 1 -> keyframe, 0-> not
  145.     int qp_table_linesize;                ///< qp_table stride
  146.     int qp_table_size;            ///< qp_table size
  147.     int8_t *qp_table;             ///< array of Quantization Parameters
  148. } AVFilterBufferRefVideoProps;
  149.  
  150. /**
  151.  * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
  152.  * a buffer to, for example, crop image without any memcpy, the buffer origin
  153.  * and dimensions are per-reference properties. Linesize is also useful for
  154.  * image flipping, frame to field filters, etc, and so is also per-reference.
  155.  *
  156.  * TODO: add anything necessary for frame reordering
  157.  */
  158. typedef struct AVFilterBufferRef {
  159.     AVFilterBuffer *buf;        ///< the buffer that this is a reference to
  160.     uint8_t *data[8];           ///< picture/audio data for each plane
  161.     /**
  162.      * pointers to the data planes/channels.
  163.      *
  164.      * For video, this should simply point to data[].
  165.      *
  166.      * For planar audio, each channel has a separate data pointer, and
  167.      * linesize[0] contains the size of each channel buffer.
  168.      * For packed audio, there is just one data pointer, and linesize[0]
  169.      * contains the total size of the buffer for all channels.
  170.      *
  171.      * Note: Both data and extended_data will always be set, but for planar
  172.      * audio with more channels that can fit in data, extended_data must be used
  173.      * in order to access all channels.
  174.      */
  175.     uint8_t **extended_data;
  176.     int linesize[8];            ///< number of bytes per line
  177.  
  178.     AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
  179.     AVFilterBufferRefAudioProps *audio; ///< audio buffer specific properties
  180.  
  181.     /**
  182.      * presentation timestamp. The time unit may change during
  183.      * filtering, as it is specified in the link and the filter code
  184.      * may need to rescale the PTS accordingly.
  185.      */
  186.     int64_t pts;
  187.     int64_t pos;                ///< byte position in stream, -1 if unknown
  188.  
  189.     int format;                 ///< media format
  190.  
  191.     int perms;                  ///< permissions, see the AV_PERM_* flags
  192.  
  193.     enum AVMediaType type;      ///< media type of buffer data
  194.  
  195.     AVDictionary *metadata;     ///< dictionary containing metadata key=value tags
  196. } AVFilterBufferRef;
  197.  
  198. /**
  199.  * Copy properties of src to dst, without copying the actual data
  200.  */
  201. attribute_deprecated
  202. void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, const AVFilterBufferRef *src);
  203.  
  204. /**
  205.  * Add a new reference to a buffer.
  206.  *
  207.  * @param ref   an existing reference to the buffer
  208.  * @param pmask a bitmask containing the allowable permissions in the new
  209.  *              reference
  210.  * @return      a new reference to the buffer with the same properties as the
  211.  *              old, excluding any permissions denied by pmask
  212.  */
  213. attribute_deprecated
  214. AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
  215.  
  216. /**
  217.  * Remove a reference to a buffer. If this is the last reference to the
  218.  * buffer, the buffer itself is also automatically freed.
  219.  *
  220.  * @param ref reference to the buffer, may be NULL
  221.  *
  222.  * @note it is recommended to use avfilter_unref_bufferp() instead of this
  223.  * function
  224.  */
  225. attribute_deprecated
  226. void avfilter_unref_buffer(AVFilterBufferRef *ref);
  227.  
  228. /**
  229.  * Remove a reference to a buffer and set the pointer to NULL.
  230.  * If this is the last reference to the buffer, the buffer itself
  231.  * is also automatically freed.
  232.  *
  233.  * @param ref pointer to the buffer reference
  234.  */
  235. attribute_deprecated
  236. void avfilter_unref_bufferp(AVFilterBufferRef **ref);
  237.  
  238. /**
  239.  * Get the number of channels of a buffer reference.
  240.  */
  241. attribute_deprecated
  242. int avfilter_ref_get_channels(AVFilterBufferRef *ref);
  243. #endif
  244.  
  245. #if FF_API_AVFILTERPAD_PUBLIC
  246. /**
  247.  * A filter pad used for either input or output.
  248.  *
  249.  * See doc/filter_design.txt for details on how to implement the methods.
  250.  *
  251.  * @warning this struct might be removed from public API.
  252.  * users should call avfilter_pad_get_name() and avfilter_pad_get_type()
  253.  * to access the name and type fields; there should be no need to access
  254.  * any other fields from outside of libavfilter.
  255.  */
  256. struct AVFilterPad {
  257.     /**
  258.      * Pad name. The name is unique among inputs and among outputs, but an
  259.      * input may have the same name as an output. This may be NULL if this
  260.      * pad has no need to ever be referenced by name.
  261.      */
  262.     const char *name;
  263.  
  264.     /**
  265.      * AVFilterPad type.
  266.      */
  267.     enum AVMediaType type;
  268.  
  269.     /**
  270.      * Input pads:
  271.      * Minimum required permissions on incoming buffers. Any buffer with
  272.      * insufficient permissions will be automatically copied by the filter
  273.      * system to a new buffer which provides the needed access permissions.
  274.      *
  275.      * Output pads:
  276.      * Guaranteed permissions on outgoing buffers. Any buffer pushed on the
  277.      * link must have at least these permissions; this fact is checked by
  278.      * asserts. It can be used to optimize buffer allocation.
  279.      */
  280.     attribute_deprecated int min_perms;
  281.  
  282.     /**
  283.      * Input pads:
  284.      * Permissions which are not accepted on incoming buffers. Any buffer
  285.      * which has any of these permissions set will be automatically copied
  286.      * by the filter system to a new buffer which does not have those
  287.      * permissions. This can be used to easily disallow buffers with
  288.      * AV_PERM_REUSE.
  289.      *
  290.      * Output pads:
  291.      * Permissions which are automatically removed on outgoing buffers. It
  292.      * can be used to optimize buffer allocation.
  293.      */
  294.     attribute_deprecated int rej_perms;
  295.  
  296.     /**
  297.      * @deprecated unused
  298.      */
  299.     int (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
  300.  
  301.     /**
  302.      * Callback function to get a video buffer. If NULL, the filter system will
  303.      * use ff_default_get_video_buffer().
  304.      *
  305.      * Input video pads only.
  306.      */
  307.     AVFrame *(*get_video_buffer)(AVFilterLink *link, int w, int h);
  308.  
  309.     /**
  310.      * Callback function to get an audio buffer. If NULL, the filter system will
  311.      * use ff_default_get_audio_buffer().
  312.      *
  313.      * Input audio pads only.
  314.      */
  315.     AVFrame *(*get_audio_buffer)(AVFilterLink *link, int nb_samples);
  316.  
  317.     /**
  318.      * @deprecated unused
  319.      */
  320.     int (*end_frame)(AVFilterLink *link);
  321.  
  322.     /**
  323.      * @deprecated unused
  324.      */
  325.     int (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
  326.  
  327.     /**
  328.      * Filtering callback. This is where a filter receives a frame with
  329.      * audio/video data and should do its processing.
  330.      *
  331.      * Input pads only.
  332.      *
  333.      * @return >= 0 on success, a negative AVERROR on error. This function
  334.      * must ensure that frame is properly unreferenced on error if it
  335.      * hasn't been passed on to another filter.
  336.      */
  337.     int (*filter_frame)(AVFilterLink *link, AVFrame *frame);
  338.  
  339.     /**
  340.      * Frame poll callback. This returns the number of immediately available
  341.      * samples. It should return a positive value if the next request_frame()
  342.      * is guaranteed to return one frame (with no delay).
  343.      *
  344.      * Defaults to just calling the source poll_frame() method.
  345.      *
  346.      * Output pads only.
  347.      */
  348.     int (*poll_frame)(AVFilterLink *link);
  349.  
  350.     /**
  351.      * Frame request callback. A call to this should result in at least one
  352.      * frame being output over the given link. This should return zero on
  353.      * success, and another value on error.
  354.      * See ff_request_frame() for the error codes with a specific
  355.      * meaning.
  356.      *
  357.      * Output pads only.
  358.      */
  359.     int (*request_frame)(AVFilterLink *link);
  360.  
  361.     /**
  362.      * Link configuration callback.
  363.      *
  364.      * For output pads, this should set the following link properties:
  365.      * video: width, height, sample_aspect_ratio, time_base
  366.      * audio: sample_rate.
  367.      *
  368.      * This should NOT set properties such as format, channel_layout, etc which
  369.      * are negotiated between filters by the filter system using the
  370.      * query_formats() callback before this function is called.
  371.      *
  372.      * For input pads, this should check the properties of the link, and update
  373.      * the filter's internal state as necessary.
  374.      *
  375.      * For both input and output pads, this should return zero on success,
  376.      * and another value on error.
  377.      */
  378.     int (*config_props)(AVFilterLink *link);
  379.  
  380.     /**
  381.      * The filter expects a fifo to be inserted on its input link,
  382.      * typically because it has a delay.
  383.      *
  384.      * input pads only.
  385.      */
  386.     int needs_fifo;
  387.  
  388.     /**
  389.      * The filter expects writable frames from its input link,
  390.      * duplicating data buffers if needed.
  391.      *
  392.      * input pads only.
  393.      */
  394.     int needs_writable;
  395. };
  396. #endif
  397.  
  398. /**
  399.  * Get the number of elements in a NULL-terminated array of AVFilterPads (e.g.
  400.  * AVFilter.inputs/outputs).
  401.  */
  402. int avfilter_pad_count(const AVFilterPad *pads);
  403.  
  404. /**
  405.  * Get the name of an AVFilterPad.
  406.  *
  407.  * @param pads an array of AVFilterPads
  408.  * @param pad_idx index of the pad in the array it; is the caller's
  409.  *                responsibility to ensure the index is valid
  410.  *
  411.  * @return name of the pad_idx'th pad in pads
  412.  */
  413. const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
  414.  
  415. /**
  416.  * Get the type of an AVFilterPad.
  417.  *
  418.  * @param pads an array of AVFilterPads
  419.  * @param pad_idx index of the pad in the array; it is the caller's
  420.  *                responsibility to ensure the index is valid
  421.  *
  422.  * @return type of the pad_idx'th pad in pads
  423.  */
  424. enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
  425.  
  426. /**
  427.  * The number of the filter inputs is not determined just by AVFilter.inputs.
  428.  * The filter might add additional inputs during initialization depending on the
  429.  * options supplied to it.
  430.  */
  431. #define AVFILTER_FLAG_DYNAMIC_INPUTS        (1 << 0)
  432. /**
  433.  * The number of the filter outputs is not determined just by AVFilter.outputs.
  434.  * The filter might add additional outputs during initialization depending on
  435.  * the options supplied to it.
  436.  */
  437. #define AVFILTER_FLAG_DYNAMIC_OUTPUTS       (1 << 1)
  438. /**
  439.  * The filter supports multithreading by splitting frames into multiple parts
  440.  * and processing them concurrently.
  441.  */
  442. #define AVFILTER_FLAG_SLICE_THREADS         (1 << 2)
  443. /**
  444.  * Some filters support a generic "enable" expression option that can be used
  445.  * to enable or disable a filter in the timeline. Filters supporting this
  446.  * option have this flag set. When the enable expression is false, the default
  447.  * no-op filter_frame() function is called in place of the filter_frame()
  448.  * callback defined on each input pad, thus the frame is passed unchanged to
  449.  * the next filters.
  450.  */
  451. #define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC  (1 << 16)
  452. /**
  453.  * Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will
  454.  * have its filter_frame() callback(s) called as usual even when the enable
  455.  * expression is false. The filter will disable filtering within the
  456.  * filter_frame() callback(s) itself, for example executing code depending on
  457.  * the AVFilterContext->is_disabled value.
  458.  */
  459. #define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL (1 << 17)
  460. /**
  461.  * Handy mask to test whether the filter supports or no the timeline feature
  462.  * (internally or generically).
  463.  */
  464. #define AVFILTER_FLAG_SUPPORT_TIMELINE (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
  465.  
  466. /**
  467.  * Filter definition. This defines the pads a filter contains, and all the
  468.  * callback functions used to interact with the filter.
  469.  */
  470. typedef struct AVFilter {
  471.     /**
  472.      * Filter name. Must be non-NULL and unique among filters.
  473.      */
  474.     const char *name;
  475.  
  476.     /**
  477.      * A description of the filter. May be NULL.
  478.      *
  479.      * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
  480.      */
  481.     const char *description;
  482.  
  483.     /**
  484.      * List of inputs, terminated by a zeroed element.
  485.      *
  486.      * NULL if there are no (static) inputs. Instances of filters with
  487.      * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
  488.      * this list.
  489.      */
  490.     const AVFilterPad *inputs;
  491.     /**
  492.      * List of outputs, terminated by a zeroed element.
  493.      *
  494.      * NULL if there are no (static) outputs. Instances of filters with
  495.      * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
  496.      * this list.
  497.      */
  498.     const AVFilterPad *outputs;
  499.  
  500.     /**
  501.      * A class for the private data, used to declare filter private AVOptions.
  502.      * This field is NULL for filters that do not declare any options.
  503.      *
  504.      * If this field is non-NULL, the first member of the filter private data
  505.      * must be a pointer to AVClass, which will be set by libavfilter generic
  506.      * code to this class.
  507.      */
  508.     const AVClass *priv_class;
  509.  
  510.     /**
  511.      * A combination of AVFILTER_FLAG_*
  512.      */
  513.     int flags;
  514.  
  515.     /*****************************************************************
  516.      * All fields below this line are not part of the public API. They
  517.      * may not be used outside of libavfilter and can be changed and
  518.      * removed at will.
  519.      * New public fields should be added right above.
  520.      *****************************************************************
  521.      */
  522.  
  523.     /**
  524.      * Filter initialization function.
  525.      *
  526.      * This callback will be called only once during the filter lifetime, after
  527.      * all the options have been set, but before links between filters are
  528.      * established and format negotiation is done.
  529.      *
  530.      * Basic filter initialization should be done here. Filters with dynamic
  531.      * inputs and/or outputs should create those inputs/outputs here based on
  532.      * provided options. No more changes to this filter's inputs/outputs can be
  533.      * done after this callback.
  534.      *
  535.      * This callback must not assume that the filter links exist or frame
  536.      * parameters are known.
  537.      *
  538.      * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
  539.      * initialization fails, so this callback does not have to clean up on
  540.      * failure.
  541.      *
  542.      * @return 0 on success, a negative AVERROR on failure
  543.      */
  544.     int (*init)(AVFilterContext *ctx);
  545.  
  546.     /**
  547.      * Should be set instead of @ref AVFilter.init "init" by the filters that
  548.      * want to pass a dictionary of AVOptions to nested contexts that are
  549.      * allocated during init.
  550.      *
  551.      * On return, the options dict should be freed and replaced with one that
  552.      * contains all the options which could not be processed by this filter (or
  553.      * with NULL if all the options were processed).
  554.      *
  555.      * Otherwise the semantics is the same as for @ref AVFilter.init "init".
  556.      */
  557.     int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
  558.  
  559.     /**
  560.      * Filter uninitialization function.
  561.      *
  562.      * Called only once right before the filter is freed. Should deallocate any
  563.      * memory held by the filter, release any buffer references, etc. It does
  564.      * not need to deallocate the AVFilterContext.priv memory itself.
  565.      *
  566.      * This callback may be called even if @ref AVFilter.init "init" was not
  567.      * called or failed, so it must be prepared to handle such a situation.
  568.      */
  569.     void (*uninit)(AVFilterContext *ctx);
  570.  
  571.     /**
  572.      * Query formats supported by the filter on its inputs and outputs.
  573.      *
  574.      * This callback is called after the filter is initialized (so the inputs
  575.      * and outputs are fixed), shortly before the format negotiation. This
  576.      * callback may be called more than once.
  577.      *
  578.      * This callback must set AVFilterLink.out_formats on every input link and
  579.      * AVFilterLink.in_formats on every output link to a list of pixel/sample
  580.      * formats that the filter supports on that link. For audio links, this
  581.      * filter must also set @ref AVFilterLink.in_samplerates "in_samplerates" /
  582.      * @ref AVFilterLink.out_samplerates "out_samplerates" and
  583.      * @ref AVFilterLink.in_channel_layouts "in_channel_layouts" /
  584.      * @ref AVFilterLink.out_channel_layouts "out_channel_layouts" analogously.
  585.      *
  586.      * This callback may be NULL for filters with one input, in which case
  587.      * libavfilter assumes that it supports all input formats and preserves
  588.      * them on output.
  589.      *
  590.      * @return zero on success, a negative value corresponding to an
  591.      * AVERROR code otherwise
  592.      */
  593.     int (*query_formats)(AVFilterContext *);
  594.  
  595.     int priv_size;      ///< size of private data to allocate for the filter
  596.  
  597.     /**
  598.      * Used by the filter registration system. Must not be touched by any other
  599.      * code.
  600.      */
  601.     struct AVFilter *next;
  602.  
  603.     /**
  604.      * Make the filter instance process a command.
  605.      *
  606.      * @param cmd    the command to process, for handling simplicity all commands must be alphanumeric only
  607.      * @param arg    the argument for the command
  608.      * @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.
  609.      * @param flags  if AVFILTER_CMD_FLAG_FAST is set and the command would be
  610.      *               time consuming then a filter should treat it like an unsupported command
  611.      *
  612.      * @returns >=0 on success otherwise an error code.
  613.      *          AVERROR(ENOSYS) on unsupported commands
  614.      */
  615.     int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);
  616.  
  617.     /**
  618.      * Filter initialization function, alternative to the init()
  619.      * callback. Args contains the user-supplied parameters, opaque is
  620.      * used for providing binary data.
  621.      */
  622.     int (*init_opaque)(AVFilterContext *ctx, void *opaque);
  623. } AVFilter;
  624.  
  625. /**
  626.  * Process multiple parts of the frame concurrently.
  627.  */
  628. #define AVFILTER_THREAD_SLICE (1 << 0)
  629.  
  630. typedef struct AVFilterInternal AVFilterInternal;
  631.  
  632. /** An instance of a filter */
  633. struct AVFilterContext {
  634.     const AVClass *av_class;        ///< needed for av_log() and filters common options
  635.  
  636.     const AVFilter *filter;         ///< the AVFilter of which this is an instance
  637.  
  638.     char *name;                     ///< name of this filter instance
  639.  
  640.     AVFilterPad   *input_pads;      ///< array of input pads
  641.     AVFilterLink **inputs;          ///< array of pointers to input links
  642. #if FF_API_FOO_COUNT
  643.     attribute_deprecated unsigned input_count; ///< @deprecated use nb_inputs
  644. #endif
  645.     unsigned    nb_inputs;          ///< number of input pads
  646.  
  647.     AVFilterPad   *output_pads;     ///< array of output pads
  648.     AVFilterLink **outputs;         ///< array of pointers to output links
  649. #if FF_API_FOO_COUNT
  650.     attribute_deprecated unsigned output_count; ///< @deprecated use nb_outputs
  651. #endif
  652.     unsigned    nb_outputs;         ///< number of output pads
  653.  
  654.     void *priv;                     ///< private data for use by the filter
  655.  
  656.     struct AVFilterGraph *graph;    ///< filtergraph this filter belongs to
  657.  
  658.     /**
  659.      * Type of multithreading being allowed/used. A combination of
  660.      * AVFILTER_THREAD_* flags.
  661.      *
  662.      * May be set by the caller before initializing the filter to forbid some
  663.      * or all kinds of multithreading for this filter. The default is allowing
  664.      * everything.
  665.      *
  666.      * When the filter is initialized, this field is combined using bit AND with
  667.      * AVFilterGraph.thread_type to get the final mask used for determining
  668.      * allowed threading types. I.e. a threading type needs to be set in both
  669.      * to be allowed.
  670.      *
  671.      * After the filter is initialized, libavfilter sets this field to the
  672.      * threading type that is actually used (0 for no multithreading).
  673.      */
  674.     int thread_type;
  675.  
  676.     /**
  677.      * An opaque struct for libavfilter internal use.
  678.      */
  679.     AVFilterInternal *internal;
  680.  
  681.     struct AVFilterCommand *command_queue;
  682.  
  683.     char *enable_str;               ///< enable expression string
  684.     void *enable;                   ///< parsed expression (AVExpr*)
  685.     double *var_values;             ///< variable values for the enable expression
  686.     int is_disabled;                ///< the enabled state from the last expression evaluation
  687. };
  688.  
  689. /**
  690.  * A link between two filters. This contains pointers to the source and
  691.  * destination filters between which this link exists, and the indexes of
  692.  * the pads involved. In addition, this link also contains the parameters
  693.  * which have been negotiated and agreed upon between the filter, such as
  694.  * image dimensions, format, etc.
  695.  */
  696. struct AVFilterLink {
  697.     AVFilterContext *src;       ///< source filter
  698.     AVFilterPad *srcpad;        ///< output pad on the source filter
  699.  
  700.     AVFilterContext *dst;       ///< dest filter
  701.     AVFilterPad *dstpad;        ///< input pad on the dest filter
  702.  
  703.     enum AVMediaType type;      ///< filter media type
  704.  
  705.     /* These parameters apply only to video */
  706.     int w;                      ///< agreed upon image width
  707.     int h;                      ///< agreed upon image height
  708.     AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
  709.     /* These parameters apply only to audio */
  710.     uint64_t channel_layout;    ///< channel layout of current buffer (see libavutil/channel_layout.h)
  711.     int sample_rate;            ///< samples per second
  712.  
  713.     int format;                 ///< agreed upon media format
  714.  
  715.     /**
  716.      * Define the time base used by the PTS of the frames/samples
  717.      * which will pass through this link.
  718.      * During the configuration stage, each filter is supposed to
  719.      * change only the output timebase, while the timebase of the
  720.      * input link is assumed to be an unchangeable property.
  721.      */
  722.     AVRational time_base;
  723.  
  724.     /*****************************************************************
  725.      * All fields below this line are not part of the public API. They
  726.      * may not be used outside of libavfilter and can be changed and
  727.      * removed at will.
  728.      * New public fields should be added right above.
  729.      *****************************************************************
  730.      */
  731.     /**
  732.      * Lists of formats and channel layouts supported by the input and output
  733.      * filters respectively. These lists are used for negotiating the format
  734.      * to actually be used, which will be loaded into the format and
  735.      * channel_layout members, above, when chosen.
  736.      *
  737.      */
  738.     AVFilterFormats *in_formats;
  739.     AVFilterFormats *out_formats;
  740.  
  741.     /**
  742.      * Lists of channel layouts and sample rates used for automatic
  743.      * negotiation.
  744.      */
  745.     AVFilterFormats  *in_samplerates;
  746.     AVFilterFormats *out_samplerates;
  747.     struct AVFilterChannelLayouts  *in_channel_layouts;
  748.     struct AVFilterChannelLayouts *out_channel_layouts;
  749.  
  750.     /**
  751.      * Audio only, the destination filter sets this to a non-zero value to
  752.      * request that buffers with the given number of samples should be sent to
  753.      * it. AVFilterPad.needs_fifo must also be set on the corresponding input
  754.      * pad.
  755.      * Last buffer before EOF will be padded with silence.
  756.      */
  757.     int request_samples;
  758.  
  759.     /** stage of the initialization of the link properties (dimensions, etc) */
  760.     enum {
  761.         AVLINK_UNINIT = 0,      ///< not started
  762.         AVLINK_STARTINIT,       ///< started, but incomplete
  763.         AVLINK_INIT             ///< complete
  764.     } init_state;
  765.  
  766. #if FF_API_AVFILTERBUFFER
  767.     struct AVFilterPool *pool;
  768. #endif
  769.  
  770.     /**
  771.      * Graph the filter belongs to.
  772.      */
  773.     struct AVFilterGraph *graph;
  774.  
  775.     /**
  776.      * Current timestamp of the link, as defined by the most recent
  777.      * frame(s), in AV_TIME_BASE units.
  778.      */
  779.     int64_t current_pts;
  780.  
  781.     /**
  782.      * Index in the age array.
  783.      */
  784.     int age_index;
  785.  
  786.     /**
  787.      * Frame rate of the stream on the link, or 1/0 if unknown;
  788.      * if left to 0/0, will be automatically be copied from the first input
  789.      * of the source filter if it exists.
  790.      *
  791.      * Sources should set it to the best estimation of the real frame rate.
  792.      * Filters should update it if necessary depending on their function.
  793.      * Sinks can use it to set a default output frame rate.
  794.      * It is similar to the r_frame_rate field in AVStream.
  795.      */
  796.     AVRational frame_rate;
  797.  
  798.     /**
  799.      * Buffer partially filled with samples to achieve a fixed/minimum size.
  800.      */
  801.     AVFrame *partial_buf;
  802.  
  803.     /**
  804.      * Size of the partial buffer to allocate.
  805.      * Must be between min_samples and max_samples.
  806.      */
  807.     int partial_buf_size;
  808.  
  809.     /**
  810.      * Minimum number of samples to filter at once. If filter_frame() is
  811.      * called with fewer samples, it will accumulate them in partial_buf.
  812.      * This field and the related ones must not be changed after filtering
  813.      * has started.
  814.      * If 0, all related fields are ignored.
  815.      */
  816.     int min_samples;
  817.  
  818.     /**
  819.      * Maximum number of samples to filter at once. If filter_frame() is
  820.      * called with more samples, it will split them.
  821.      */
  822.     int max_samples;
  823.  
  824. #if FF_API_AVFILTERBUFFER
  825.     /**
  826.      * The buffer reference currently being received across the link by the
  827.      * destination filter. This is used internally by the filter system to
  828.      * allow automatic copying of buffers which do not have sufficient
  829.      * permissions for the destination. This should not be accessed directly
  830.      * by the filters.
  831.      */
  832.     AVFilterBufferRef *cur_buf_copy;
  833. #endif
  834.  
  835.     /**
  836.      * True if the link is closed.
  837.      * If set, all attempts of start_frame, filter_frame or request_frame
  838.      * will fail with AVERROR_EOF, and if necessary the reference will be
  839.      * destroyed.
  840.      * If request_frame returns AVERROR_EOF, this flag is set on the
  841.      * corresponding link.
  842.      * It can be set also be set by either the source or the destination
  843.      * filter.
  844.      */
  845.     int closed;
  846.  
  847.     /**
  848.      * Number of channels.
  849.      */
  850.     int channels;
  851.  
  852.     /**
  853.      * True if a frame is being requested on the link.
  854.      * Used internally by the framework.
  855.      */
  856.     unsigned frame_requested;
  857.  
  858.     /**
  859.      * Link processing flags.
  860.      */
  861.     unsigned flags;
  862.  
  863.     /**
  864.      * Number of past frames sent through the link.
  865.      */
  866.     int64_t frame_count;
  867. };
  868.  
  869. /**
  870.  * Link two filters together.
  871.  *
  872.  * @param src    the source filter
  873.  * @param srcpad index of the output pad on the source filter
  874.  * @param dst    the destination filter
  875.  * @param dstpad index of the input pad on the destination filter
  876.  * @return       zero on success
  877.  */
  878. int avfilter_link(AVFilterContext *src, unsigned srcpad,
  879.                   AVFilterContext *dst, unsigned dstpad);
  880.  
  881. /**
  882.  * Free the link in *link, and set its pointer to NULL.
  883.  */
  884. void avfilter_link_free(AVFilterLink **link);
  885.  
  886. /**
  887.  * Get the number of channels of a link.
  888.  */
  889. int avfilter_link_get_channels(AVFilterLink *link);
  890.  
  891. /**
  892.  * Set the closed field of a link.
  893.  */
  894. void avfilter_link_set_closed(AVFilterLink *link, int closed);
  895.  
  896. /**
  897.  * Negotiate the media format, dimensions, etc of all inputs to a filter.
  898.  *
  899.  * @param filter the filter to negotiate the properties for its inputs
  900.  * @return       zero on successful negotiation
  901.  */
  902. int avfilter_config_links(AVFilterContext *filter);
  903.  
  904. #if FF_API_AVFILTERBUFFER
  905. /**
  906.  * Create a buffer reference wrapped around an already allocated image
  907.  * buffer.
  908.  *
  909.  * @param data pointers to the planes of the image to reference
  910.  * @param linesize linesizes for the planes of the image to reference
  911.  * @param perms the required access permissions
  912.  * @param w the width of the image specified by the data and linesize arrays
  913.  * @param h the height of the image specified by the data and linesize arrays
  914.  * @param format the pixel format of the image specified by the data and linesize arrays
  915.  */
  916. attribute_deprecated
  917. AVFilterBufferRef *
  918. avfilter_get_video_buffer_ref_from_arrays(uint8_t * const data[4], const int linesize[4], int perms,
  919.                                           int w, int h, enum AVPixelFormat format);
  920.  
  921. /**
  922.  * Create an audio buffer reference wrapped around an already
  923.  * allocated samples buffer.
  924.  *
  925.  * See avfilter_get_audio_buffer_ref_from_arrays_channels() for a version
  926.  * that can handle unknown channel layouts.
  927.  *
  928.  * @param data           pointers to the samples plane buffers
  929.  * @param linesize       linesize for the samples plane buffers
  930.  * @param perms          the required access permissions
  931.  * @param nb_samples     number of samples per channel
  932.  * @param sample_fmt     the format of each sample in the buffer to allocate
  933.  * @param channel_layout the channel layout of the buffer
  934.  */
  935. attribute_deprecated
  936. AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
  937.                                                              int linesize,
  938.                                                              int perms,
  939.                                                              int nb_samples,
  940.                                                              enum AVSampleFormat sample_fmt,
  941.                                                              uint64_t channel_layout);
  942. /**
  943.  * Create an audio buffer reference wrapped around an already
  944.  * allocated samples buffer.
  945.  *
  946.  * @param data           pointers to the samples plane buffers
  947.  * @param linesize       linesize for the samples plane buffers
  948.  * @param perms          the required access permissions
  949.  * @param nb_samples     number of samples per channel
  950.  * @param sample_fmt     the format of each sample in the buffer to allocate
  951.  * @param channels       the number of channels of the buffer
  952.  * @param channel_layout the channel layout of the buffer,
  953.  *                       must be either 0 or consistent with channels
  954.  */
  955. attribute_deprecated
  956. AVFilterBufferRef *avfilter_get_audio_buffer_ref_from_arrays_channels(uint8_t **data,
  957.                                                                       int linesize,
  958.                                                                       int perms,
  959.                                                                       int nb_samples,
  960.                                                                       enum AVSampleFormat sample_fmt,
  961.                                                                       int channels,
  962.                                                                       uint64_t channel_layout);
  963.  
  964. #endif
  965.  
  966.  
  967. #define AVFILTER_CMD_FLAG_ONE   1 ///< Stop once a filter understood the command (for target=all for example), fast filters are favored automatically
  968. #define AVFILTER_CMD_FLAG_FAST  2 ///< Only execute command when its fast (like a video out that supports contrast adjustment in hw)
  969.  
  970. /**
  971.  * Make the filter instance process a command.
  972.  * It is recommended to use avfilter_graph_send_command().
  973.  */
  974. int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
  975.  
  976. /** Initialize the filter system. Register all builtin filters. */
  977. void avfilter_register_all(void);
  978.  
  979. #if FF_API_OLD_FILTER_REGISTER
  980. /** Uninitialize the filter system. Unregister all filters. */
  981. attribute_deprecated
  982. void avfilter_uninit(void);
  983. #endif
  984.  
  985. /**
  986.  * Register a filter. This is only needed if you plan to use
  987.  * avfilter_get_by_name later to lookup the AVFilter structure by name. A
  988.  * filter can still by instantiated with avfilter_graph_alloc_filter even if it
  989.  * is not registered.
  990.  *
  991.  * @param filter the filter to register
  992.  * @return 0 if the registration was successful, a negative value
  993.  * otherwise
  994.  */
  995. int avfilter_register(AVFilter *filter);
  996.  
  997. /**
  998.  * Get a filter definition matching the given name.
  999.  *
  1000.  * @param name the filter name to find
  1001.  * @return     the filter definition, if any matching one is registered.
  1002.  *             NULL if none found.
  1003.  */
  1004. #if !FF_API_NOCONST_GET_NAME
  1005. const
  1006. #endif
  1007. AVFilter *avfilter_get_by_name(const char *name);
  1008.  
  1009. /**
  1010.  * Iterate over all registered filters.
  1011.  * @return If prev is non-NULL, next registered filter after prev or NULL if
  1012.  * prev is the last filter. If prev is NULL, return the first registered filter.
  1013.  */
  1014. const AVFilter *avfilter_next(const AVFilter *prev);
  1015.  
  1016. #if FF_API_OLD_FILTER_REGISTER
  1017. /**
  1018.  * If filter is NULL, returns a pointer to the first registered filter pointer,
  1019.  * if filter is non-NULL, returns the next pointer after filter.
  1020.  * If the returned pointer points to NULL, the last registered filter
  1021.  * was already reached.
  1022.  * @deprecated use avfilter_next()
  1023.  */
  1024. attribute_deprecated
  1025. AVFilter **av_filter_next(AVFilter **filter);
  1026. #endif
  1027.  
  1028. #if FF_API_AVFILTER_OPEN
  1029. /**
  1030.  * Create a filter instance.
  1031.  *
  1032.  * @param filter_ctx put here a pointer to the created filter context
  1033.  * on success, NULL on failure
  1034.  * @param filter    the filter to create an instance of
  1035.  * @param inst_name Name to give to the new instance. Can be NULL for none.
  1036.  * @return >= 0 in case of success, a negative error code otherwise
  1037.  * @deprecated use avfilter_graph_alloc_filter() instead
  1038.  */
  1039. attribute_deprecated
  1040. int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
  1041. #endif
  1042.  
  1043.  
  1044. #if FF_API_AVFILTER_INIT_FILTER
  1045. /**
  1046.  * Initialize a filter.
  1047.  *
  1048.  * @param filter the filter to initialize
  1049.  * @param args   A string of parameters to use when initializing the filter.
  1050.  *               The format and meaning of this string varies by filter.
  1051.  * @param opaque Any extra non-string data needed by the filter. The meaning
  1052.  *               of this parameter varies by filter.
  1053.  * @return       zero on success
  1054.  */
  1055. attribute_deprecated
  1056. int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
  1057. #endif
  1058.  
  1059. /**
  1060.  * Initialize a filter with the supplied parameters.
  1061.  *
  1062.  * @param ctx  uninitialized filter context to initialize
  1063.  * @param args Options to initialize the filter with. This must be a
  1064.  *             ':'-separated list of options in the 'key=value' form.
  1065.  *             May be NULL if the options have been set directly using the
  1066.  *             AVOptions API or there are no options that need to be set.
  1067.  * @return 0 on success, a negative AVERROR on failure
  1068.  */
  1069. int avfilter_init_str(AVFilterContext *ctx, const char *args);
  1070.  
  1071. /**
  1072.  * Initialize a filter with the supplied dictionary of options.
  1073.  *
  1074.  * @param ctx     uninitialized filter context to initialize
  1075.  * @param options An AVDictionary filled with options for this filter. On
  1076.  *                return this parameter will be destroyed and replaced with
  1077.  *                a dict containing options that were not found. This dictionary
  1078.  *                must be freed by the caller.
  1079.  *                May be NULL, then this function is equivalent to
  1080.  *                avfilter_init_str() with the second parameter set to NULL.
  1081.  * @return 0 on success, a negative AVERROR on failure
  1082.  *
  1083.  * @note This function and avfilter_init_str() do essentially the same thing,
  1084.  * the difference is in manner in which the options are passed. It is up to the
  1085.  * calling code to choose whichever is more preferable. The two functions also
  1086.  * behave differently when some of the provided options are not declared as
  1087.  * supported by the filter. In such a case, avfilter_init_str() will fail, but
  1088.  * this function will leave those extra options in the options AVDictionary and
  1089.  * continue as usual.
  1090.  */
  1091. int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
  1092.  
  1093. /**
  1094.  * Free a filter context. This will also remove the filter from its
  1095.  * filtergraph's list of filters.
  1096.  *
  1097.  * @param filter the filter to free
  1098.  */
  1099. void avfilter_free(AVFilterContext *filter);
  1100.  
  1101. /**
  1102.  * Insert a filter in the middle of an existing link.
  1103.  *
  1104.  * @param link the link into which the filter should be inserted
  1105.  * @param filt the filter to be inserted
  1106.  * @param filt_srcpad_idx the input pad on the filter to connect
  1107.  * @param filt_dstpad_idx the output pad on the filter to connect
  1108.  * @return     zero on success
  1109.  */
  1110. int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
  1111.                            unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
  1112.  
  1113. #if FF_API_AVFILTERBUFFER
  1114. /**
  1115.  * Copy the frame properties of src to dst, without copying the actual
  1116.  * image data.
  1117.  *
  1118.  * @return 0 on success, a negative number on error.
  1119.  */
  1120. attribute_deprecated
  1121. int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src);
  1122.  
  1123. /**
  1124.  * Copy the frame properties and data pointers of src to dst, without copying
  1125.  * the actual data.
  1126.  *
  1127.  * @return 0 on success, a negative number on error.
  1128.  */
  1129. attribute_deprecated
  1130. int avfilter_copy_buf_props(AVFrame *dst, const AVFilterBufferRef *src);
  1131. #endif
  1132.  
  1133. /**
  1134.  * @return AVClass for AVFilterContext.
  1135.  *
  1136.  * @see av_opt_find().
  1137.  */
  1138. const AVClass *avfilter_get_class(void);
  1139.  
  1140. typedef struct AVFilterGraphInternal AVFilterGraphInternal;
  1141.  
  1142. /**
  1143.  * A function pointer passed to the @ref AVFilterGraph.execute callback to be
  1144.  * executed multiple times, possibly in parallel.
  1145.  *
  1146.  * @param ctx the filter context the job belongs to
  1147.  * @param arg an opaque parameter passed through from @ref
  1148.  *            AVFilterGraph.execute
  1149.  * @param jobnr the index of the job being executed
  1150.  * @param nb_jobs the total number of jobs
  1151.  *
  1152.  * @return 0 on success, a negative AVERROR on error
  1153.  */
  1154. typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
  1155.  
  1156. /**
  1157.  * A function executing multiple jobs, possibly in parallel.
  1158.  *
  1159.  * @param ctx the filter context to which the jobs belong
  1160.  * @param func the function to be called multiple times
  1161.  * @param arg the argument to be passed to func
  1162.  * @param ret a nb_jobs-sized array to be filled with return values from each
  1163.  *            invocation of func
  1164.  * @param nb_jobs the number of jobs to execute
  1165.  *
  1166.  * @return 0 on success, a negative AVERROR on error
  1167.  */
  1168. typedef int (avfilter_execute_func)(AVFilterContext *ctx, avfilter_action_func *func,
  1169.                                     void *arg, int *ret, int nb_jobs);
  1170.  
  1171. typedef struct AVFilterGraph {
  1172.     const AVClass *av_class;
  1173. #if FF_API_FOO_COUNT
  1174.     attribute_deprecated
  1175.     unsigned filter_count_unused;
  1176. #endif
  1177.     AVFilterContext **filters;
  1178. #if !FF_API_FOO_COUNT
  1179.     unsigned nb_filters;
  1180. #endif
  1181.  
  1182.     char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
  1183.     char *resample_lavr_opts;   ///< libavresample options to use for the auto-inserted resample filters
  1184. #if FF_API_FOO_COUNT
  1185.     unsigned nb_filters;
  1186. #endif
  1187.  
  1188.     /**
  1189.      * Type of multithreading allowed for filters in this graph. A combination
  1190.      * of AVFILTER_THREAD_* flags.
  1191.      *
  1192.      * May be set by the caller at any point, the setting will apply to all
  1193.      * filters initialized after that. The default is allowing everything.
  1194.      *
  1195.      * When a filter in this graph is initialized, this field is combined using
  1196.      * bit AND with AVFilterContext.thread_type to get the final mask used for
  1197.      * determining allowed threading types. I.e. a threading type needs to be
  1198.      * set in both to be allowed.
  1199.      */
  1200.     int thread_type;
  1201.  
  1202.     /**
  1203.      * Maximum number of threads used by filters in this graph. May be set by
  1204.      * the caller before adding any filters to the filtergraph. Zero (the
  1205.      * default) means that the number of threads is determined automatically.
  1206.      */
  1207.     int nb_threads;
  1208.  
  1209.     /**
  1210.      * Opaque object for libavfilter internal use.
  1211.      */
  1212.     AVFilterGraphInternal *internal;
  1213.  
  1214.     /**
  1215.      * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
  1216.      * be used from callbacks like @ref AVFilterGraph.execute.
  1217.      * Libavfilter will not touch this field in any way.
  1218.      */
  1219.     void *opaque;
  1220.  
  1221.     /**
  1222.      * This callback may be set by the caller immediately after allocating the
  1223.      * graph and before adding any filters to it, to provide a custom
  1224.      * multithreading implementation.
  1225.      *
  1226.      * If set, filters with slice threading capability will call this callback
  1227.      * to execute multiple jobs in parallel.
  1228.      *
  1229.      * If this field is left unset, libavfilter will use its internal
  1230.      * implementation, which may or may not be multithreaded depending on the
  1231.      * platform and build options.
  1232.      */
  1233.     avfilter_execute_func *execute;
  1234.  
  1235.     char *aresample_swr_opts; ///< swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
  1236.  
  1237.     /**
  1238.      * Private fields
  1239.      *
  1240.      * The following fields are for internal use only.
  1241.      * Their type, offset, number and semantic can change without notice.
  1242.      */
  1243.  
  1244.     AVFilterLink **sink_links;
  1245.     int sink_links_count;
  1246.  
  1247.     unsigned disable_auto_convert;
  1248. } AVFilterGraph;
  1249.  
  1250. /**
  1251.  * Allocate a filter graph.
  1252.  *
  1253.  * @return the allocated filter graph on success or NULL.
  1254.  */
  1255. AVFilterGraph *avfilter_graph_alloc(void);
  1256.  
  1257. /**
  1258.  * Create a new filter instance in a filter graph.
  1259.  *
  1260.  * @param graph graph in which the new filter will be used
  1261.  * @param filter the filter to create an instance of
  1262.  * @param name Name to give to the new instance (will be copied to
  1263.  *             AVFilterContext.name). This may be used by the caller to identify
  1264.  *             different filters, libavfilter itself assigns no semantics to
  1265.  *             this parameter. May be NULL.
  1266.  *
  1267.  * @return the context of the newly created filter instance (note that it is
  1268.  *         also retrievable directly through AVFilterGraph.filters or with
  1269.  *         avfilter_graph_get_filter()) on success or NULL on failure.
  1270.  */
  1271. AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
  1272.                                              const AVFilter *filter,
  1273.                                              const char *name);
  1274.  
  1275. /**
  1276.  * Get a filter instance identified by instance name from graph.
  1277.  *
  1278.  * @param graph filter graph to search through.
  1279.  * @param name filter instance name (should be unique in the graph).
  1280.  * @return the pointer to the found filter instance or NULL if it
  1281.  * cannot be found.
  1282.  */
  1283. AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, const char *name);
  1284.  
  1285. #if FF_API_AVFILTER_OPEN
  1286. /**
  1287.  * Add an existing filter instance to a filter graph.
  1288.  *
  1289.  * @param graphctx  the filter graph
  1290.  * @param filter the filter to be added
  1291.  *
  1292.  * @deprecated use avfilter_graph_alloc_filter() to allocate a filter in a
  1293.  * filter graph
  1294.  */
  1295. attribute_deprecated
  1296. int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
  1297. #endif
  1298.  
  1299. /**
  1300.  * Create and add a filter instance into an existing graph.
  1301.  * The filter instance is created from the filter filt and inited
  1302.  * with the parameters args and opaque.
  1303.  *
  1304.  * In case of success put in *filt_ctx the pointer to the created
  1305.  * filter instance, otherwise set *filt_ctx to NULL.
  1306.  *
  1307.  * @param name the instance name to give to the created filter instance
  1308.  * @param graph_ctx the filter graph
  1309.  * @return a negative AVERROR error code in case of failure, a non
  1310.  * negative value otherwise
  1311.  */
  1312. int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
  1313.                                  const char *name, const char *args, void *opaque,
  1314.                                  AVFilterGraph *graph_ctx);
  1315.  
  1316. /**
  1317.  * Enable or disable automatic format conversion inside the graph.
  1318.  *
  1319.  * Note that format conversion can still happen inside explicitly inserted
  1320.  * scale and aresample filters.
  1321.  *
  1322.  * @param flags  any of the AVFILTER_AUTO_CONVERT_* constants
  1323.  */
  1324. void avfilter_graph_set_auto_convert(AVFilterGraph *graph, unsigned flags);
  1325.  
  1326. enum {
  1327.     AVFILTER_AUTO_CONVERT_ALL  =  0, /**< all automatic conversions enabled */
  1328.     AVFILTER_AUTO_CONVERT_NONE = -1, /**< all automatic conversions disabled */
  1329. };
  1330.  
  1331. /**
  1332.  * Check validity and configure all the links and formats in the graph.
  1333.  *
  1334.  * @param graphctx the filter graph
  1335.  * @param log_ctx context used for logging
  1336.  * @return >= 0 in case of success, a negative AVERROR code otherwise
  1337.  */
  1338. int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
  1339.  
  1340. /**
  1341.  * Free a graph, destroy its links, and set *graph to NULL.
  1342.  * If *graph is NULL, do nothing.
  1343.  */
  1344. void avfilter_graph_free(AVFilterGraph **graph);
  1345.  
  1346. /**
  1347.  * A linked-list of the inputs/outputs of the filter chain.
  1348.  *
  1349.  * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
  1350.  * where it is used to communicate open (unlinked) inputs and outputs from and
  1351.  * to the caller.
  1352.  * This struct specifies, per each not connected pad contained in the graph, the
  1353.  * filter context and the pad index required for establishing a link.
  1354.  */
  1355. typedef struct AVFilterInOut {
  1356.     /** unique name for this input/output in the list */
  1357.     char *name;
  1358.  
  1359.     /** filter context associated to this input/output */
  1360.     AVFilterContext *filter_ctx;
  1361.  
  1362.     /** index of the filt_ctx pad to use for linking */
  1363.     int pad_idx;
  1364.  
  1365.     /** next input/input in the list, NULL if this is the last */
  1366.     struct AVFilterInOut *next;
  1367. } AVFilterInOut;
  1368.  
  1369. /**
  1370.  * Allocate a single AVFilterInOut entry.
  1371.  * Must be freed with avfilter_inout_free().
  1372.  * @return allocated AVFilterInOut on success, NULL on failure.
  1373.  */
  1374. AVFilterInOut *avfilter_inout_alloc(void);
  1375.  
  1376. /**
  1377.  * Free the supplied list of AVFilterInOut and set *inout to NULL.
  1378.  * If *inout is NULL, do nothing.
  1379.  */
  1380. void avfilter_inout_free(AVFilterInOut **inout);
  1381.  
  1382. #if AV_HAVE_INCOMPATIBLE_LIBAV_ABI || !FF_API_OLD_GRAPH_PARSE
  1383. /**
  1384.  * Add a graph described by a string to a graph.
  1385.  *
  1386.  * @note The caller must provide the lists of inputs and outputs,
  1387.  * which therefore must be known before calling the function.
  1388.  *
  1389.  * @note The inputs parameter describes inputs of the already existing
  1390.  * part of the graph; i.e. from the point of view of the newly created
  1391.  * part, they are outputs. Similarly the outputs parameter describes
  1392.  * outputs of the already existing filters, which are provided as
  1393.  * inputs to the parsed filters.
  1394.  *
  1395.  * @param graph   the filter graph where to link the parsed graph context
  1396.  * @param filters string to be parsed
  1397.  * @param inputs  linked list to the inputs of the graph
  1398.  * @param outputs linked list to the outputs of the graph
  1399.  * @return zero on success, a negative AVERROR code on error
  1400.  */
  1401. int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
  1402.                          AVFilterInOut *inputs, AVFilterInOut *outputs,
  1403.                          void *log_ctx);
  1404. #else
  1405. /**
  1406.  * Add a graph described by a string to a graph.
  1407.  *
  1408.  * @param graph   the filter graph where to link the parsed graph context
  1409.  * @param filters string to be parsed
  1410.  * @param inputs  pointer to a linked list to the inputs of the graph, may be NULL.
  1411.  *                If non-NULL, *inputs is updated to contain the list of open inputs
  1412.  *                after the parsing, should be freed with avfilter_inout_free().
  1413.  * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
  1414.  *                If non-NULL, *outputs is updated to contain the list of open outputs
  1415.  *                after the parsing, should be freed with avfilter_inout_free().
  1416.  * @return non negative on success, a negative AVERROR code on error
  1417.  * @deprecated Use avfilter_graph_parse_ptr() instead.
  1418.  */
  1419. attribute_deprecated
  1420. int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
  1421.                          AVFilterInOut **inputs, AVFilterInOut **outputs,
  1422.                          void *log_ctx);
  1423. #endif
  1424.  
  1425. /**
  1426.  * Add a graph described by a string to a graph.
  1427.  *
  1428.  * In the graph filters description, if the input label of the first
  1429.  * filter is not specified, "in" is assumed; if the output label of
  1430.  * the last filter is not specified, "out" is assumed.
  1431.  *
  1432.  * @param graph   the filter graph where to link the parsed graph context
  1433.  * @param filters string to be parsed
  1434.  * @param inputs  pointer to a linked list to the inputs of the graph, may be NULL.
  1435.  *                If non-NULL, *inputs is updated to contain the list of open inputs
  1436.  *                after the parsing, should be freed with avfilter_inout_free().
  1437.  * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
  1438.  *                If non-NULL, *outputs is updated to contain the list of open outputs
  1439.  *                after the parsing, should be freed with avfilter_inout_free().
  1440.  * @return non negative on success, a negative AVERROR code on error
  1441.  */
  1442. int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
  1443.                              AVFilterInOut **inputs, AVFilterInOut **outputs,
  1444.                              void *log_ctx);
  1445.  
  1446. /**
  1447.  * Add a graph described by a string to a graph.
  1448.  *
  1449.  * @param[in]  graph   the filter graph where to link the parsed graph context
  1450.  * @param[in]  filters string to be parsed
  1451.  * @param[out] inputs  a linked list of all free (unlinked) inputs of the
  1452.  *                     parsed graph will be returned here. It is to be freed
  1453.  *                     by the caller using avfilter_inout_free().
  1454.  * @param[out] outputs a linked list of all free (unlinked) outputs of the
  1455.  *                     parsed graph will be returned here. It is to be freed by the
  1456.  *                     caller using avfilter_inout_free().
  1457.  * @return zero on success, a negative AVERROR code on error
  1458.  *
  1459.  * @note This function returns the inputs and outputs that are left
  1460.  * unlinked after parsing the graph and the caller then deals with
  1461.  * them.
  1462.  * @note This function makes no reference whatsoever to already
  1463.  * existing parts of the graph and the inputs parameter will on return
  1464.  * contain inputs of the newly parsed part of the graph.  Analogously
  1465.  * the outputs parameter will contain outputs of the newly created
  1466.  * filters.
  1467.  */
  1468. int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
  1469.                           AVFilterInOut **inputs,
  1470.                           AVFilterInOut **outputs);
  1471.  
  1472. /**
  1473.  * Send a command to one or more filter instances.
  1474.  *
  1475.  * @param graph  the filter graph
  1476.  * @param target the filter(s) to which the command should be sent
  1477.  *               "all" sends to all filters
  1478.  *               otherwise it can be a filter or filter instance name
  1479.  *               which will send the command to all matching filters.
  1480.  * @param cmd    the command to send, for handling simplicity all commands must be alphanumeric only
  1481.  * @param arg    the argument for the command
  1482.  * @param res    a buffer with size res_size where the filter(s) can return a response.
  1483.  *
  1484.  * @returns >=0 on success otherwise an error code.
  1485.  *              AVERROR(ENOSYS) on unsupported commands
  1486.  */
  1487. int avfilter_graph_send_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, char *res, int res_len, int flags);
  1488.  
  1489. /**
  1490.  * Queue a command for one or more filter instances.
  1491.  *
  1492.  * @param graph  the filter graph
  1493.  * @param target the filter(s) to which the command should be sent
  1494.  *               "all" sends to all filters
  1495.  *               otherwise it can be a filter or filter instance name
  1496.  *               which will send the command to all matching filters.
  1497.  * @param cmd    the command to sent, for handling simplicity all commands must be alphanumeric only
  1498.  * @param arg    the argument for the command
  1499.  * @param ts     time at which the command should be sent to the filter
  1500.  *
  1501.  * @note As this executes commands after this function returns, no return code
  1502.  *       from the filter is provided, also AVFILTER_CMD_FLAG_ONE is not supported.
  1503.  */
  1504. int avfilter_graph_queue_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, int flags, double ts);
  1505.  
  1506.  
  1507. /**
  1508.  * Dump a graph into a human-readable string representation.
  1509.  *
  1510.  * @param graph    the graph to dump
  1511.  * @param options  formatting options; currently ignored
  1512.  * @return  a string, or NULL in case of memory allocation failure;
  1513.  *          the string must be freed using av_free
  1514.  */
  1515. char *avfilter_graph_dump(AVFilterGraph *graph, const char *options);
  1516.  
  1517. /**
  1518.  * Request a frame on the oldest sink link.
  1519.  *
  1520.  * If the request returns AVERROR_EOF, try the next.
  1521.  *
  1522.  * Note that this function is not meant to be the sole scheduling mechanism
  1523.  * of a filtergraph, only a convenience function to help drain a filtergraph
  1524.  * in a balanced way under normal circumstances.
  1525.  *
  1526.  * Also note that AVERROR_EOF does not mean that frames did not arrive on
  1527.  * some of the sinks during the process.
  1528.  * When there are multiple sink links, in case the requested link
  1529.  * returns an EOF, this may cause a filter to flush pending frames
  1530.  * which are sent to another sink link, although unrequested.
  1531.  *
  1532.  * @return  the return value of ff_request_frame(),
  1533.  *          or AVERROR_EOF if all links returned AVERROR_EOF
  1534.  */
  1535. int avfilter_graph_request_oldest(AVFilterGraph *graph);
  1536.  
  1537. /**
  1538.  * @}
  1539.  */
  1540.  
  1541. #endif /* AVFILTER_AVFILTER_H */
  1542.