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diff --git a/dependencies/include/libavfilter/avfilter.h b/dependencies/include/libavfilter/avfilter.h
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+++ b/dependencies/include/libavfilter/avfilter.h
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+/*
+ * filter layer
+ * Copyright (c) 2007 Bobby Bingham
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFILTER_AVFILTER_H
+#define AVFILTER_AVFILTER_H
+
+/**
+ * @file
+ * @ingroup lavfi
+ * Main libavfilter public API header
+ */
+
+/**
+ * @defgroup lavfi libavfilter
+ * Graph-based frame editing library.
+ *
+ * @{
+ */
+
+#include <stddef.h>
+
+#include "libavutil/attributes.h"
+#include "libavutil/avutil.h"
+#include "libavutil/buffer.h"
+#include "libavutil/dict.h"
+#include "libavutil/frame.h"
+#include "libavutil/log.h"
+#include "libavutil/samplefmt.h"
+#include "libavutil/pixfmt.h"
+#include "libavutil/rational.h"
+
+#include "libavfilter/version_major.h"
+#ifndef HAVE_AV_CONFIG_H
+/* When included as part of the ffmpeg build, only include the major version
+ * to avoid unnecessary rebuilds. When included externally, keep including
+ * the full version information. */
+#include "libavfilter/version.h"
+#endif
+
+/**
+ * Return the LIBAVFILTER_VERSION_INT constant.
+ */
+unsigned avfilter_version(void);
+
+/**
+ * Return the libavfilter build-time configuration.
+ */
+const char *avfilter_configuration(void);
+
+/**
+ * Return the libavfilter license.
+ */
+const char *avfilter_license(void);
+
+typedef struct AVFilterContext AVFilterContext;
+typedef struct AVFilterLink    AVFilterLink;
+typedef struct AVFilterPad     AVFilterPad;
+typedef struct AVFilterFormats AVFilterFormats;
+typedef struct AVFilterChannelLayouts AVFilterChannelLayouts;
+
+#if FF_API_PAD_COUNT
+/**
+ * Get the number of elements in an AVFilter's inputs or outputs array.
+ *
+ * @deprecated Use avfilter_filter_pad_count() instead.
+ */
+attribute_deprecated
+int avfilter_pad_count(const AVFilterPad *pads);
+#endif
+
+/**
+ * Get the name of an AVFilterPad.
+ *
+ * @param pads an array of AVFilterPads
+ * @param pad_idx index of the pad in the array; it is the caller's
+ *                responsibility to ensure the index is valid
+ *
+ * @return name of the pad_idx'th pad in pads
+ */
+const char *avfilter_pad_get_name(const AVFilterPad *pads, int pad_idx);
+
+/**
+ * Get the type of an AVFilterPad.
+ *
+ * @param pads an array of AVFilterPads
+ * @param pad_idx index of the pad in the array; it is the caller's
+ *                responsibility to ensure the index is valid
+ *
+ * @return type of the pad_idx'th pad in pads
+ */
+enum AVMediaType avfilter_pad_get_type(const AVFilterPad *pads, int pad_idx);
+
+/**
+ * The number of the filter inputs is not determined just by AVFilter.inputs.
+ * The filter might add additional inputs during initialization depending on the
+ * options supplied to it.
+ */
+#define AVFILTER_FLAG_DYNAMIC_INPUTS        (1 << 0)
+/**
+ * The number of the filter outputs is not determined just by AVFilter.outputs.
+ * The filter might add additional outputs during initialization depending on
+ * the options supplied to it.
+ */
+#define AVFILTER_FLAG_DYNAMIC_OUTPUTS       (1 << 1)
+/**
+ * The filter supports multithreading by splitting frames into multiple parts
+ * and processing them concurrently.
+ */
+#define AVFILTER_FLAG_SLICE_THREADS         (1 << 2)
+/**
+ * The filter is a "metadata" filter - it does not modify the frame data in any
+ * way. It may only affect the metadata (i.e. those fields copied by
+ * av_frame_copy_props()).
+ *
+ * More precisely, this means:
+ * - video: the data of any frame output by the filter must be exactly equal to
+ *   some frame that is received on one of its inputs. Furthermore, all frames
+ *   produced on a given output must correspond to frames received on the same
+ *   input and their order must be unchanged. Note that the filter may still
+ *   drop or duplicate the frames.
+ * - audio: the data produced by the filter on any of its outputs (viewed e.g.
+ *   as an array of interleaved samples) must be exactly equal to the data
+ *   received by the filter on one of its inputs.
+ */
+#define AVFILTER_FLAG_METADATA_ONLY         (1 << 3)
+/**
+ * Some filters support a generic "enable" expression option that can be used
+ * to enable or disable a filter in the timeline. Filters supporting this
+ * option have this flag set. When the enable expression is false, the default
+ * no-op filter_frame() function is called in place of the filter_frame()
+ * callback defined on each input pad, thus the frame is passed unchanged to
+ * the next filters.
+ */
+#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC  (1 << 16)
+/**
+ * Same as AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC, except that the filter will
+ * have its filter_frame() callback(s) called as usual even when the enable
+ * expression is false. The filter will disable filtering within the
+ * filter_frame() callback(s) itself, for example executing code depending on
+ * the AVFilterContext->is_disabled value.
+ */
+#define AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL (1 << 17)
+/**
+ * Handy mask to test whether the filter supports or no the timeline feature
+ * (internally or generically).
+ */
+#define AVFILTER_FLAG_SUPPORT_TIMELINE (AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL)
+
+/**
+ * Filter definition. This defines the pads a filter contains, and all the
+ * callback functions used to interact with the filter.
+ */
+typedef struct AVFilter {
+    /**
+     * Filter name. Must be non-NULL and unique among filters.
+     */
+    const char *name;
+
+    /**
+     * A description of the filter. May be NULL.
+     *
+     * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
+     */
+    const char *description;
+
+    /**
+     * List of static inputs.
+     *
+     * NULL if there are no (static) inputs. Instances of filters with
+     * AVFILTER_FLAG_DYNAMIC_INPUTS set may have more inputs than present in
+     * this list.
+     */
+    const AVFilterPad *inputs;
+
+    /**
+     * List of static outputs.
+     *
+     * NULL if there are no (static) outputs. Instances of filters with
+     * AVFILTER_FLAG_DYNAMIC_OUTPUTS set may have more outputs than present in
+     * this list.
+     */
+    const AVFilterPad *outputs;
+
+    /**
+     * A class for the private data, used to declare filter private AVOptions.
+     * This field is NULL for filters that do not declare any options.
+     *
+     * If this field is non-NULL, the first member of the filter private data
+     * must be a pointer to AVClass, which will be set by libavfilter generic
+     * code to this class.
+     */
+    const AVClass *priv_class;
+
+    /**
+     * A combination of AVFILTER_FLAG_*
+     */
+    int flags;
+
+    /*****************************************************************
+     * All fields below this line are not part of the public API. They
+     * may not be used outside of libavfilter and can be changed and
+     * removed at will.
+     * New public fields should be added right above.
+     *****************************************************************
+     */
+
+    /**
+     * The number of entries in the list of inputs.
+     */
+    uint8_t nb_inputs;
+
+    /**
+     * The number of entries in the list of outputs.
+     */
+    uint8_t nb_outputs;
+
+    /**
+     * This field determines the state of the formats union.
+     * It is an enum FilterFormatsState value.
+     */
+    uint8_t formats_state;
+
+    /**
+     * Filter pre-initialization function
+     *
+     * This callback will be called immediately after the filter context is
+     * allocated, to allow allocating and initing sub-objects.
+     *
+     * If this callback is not NULL, the uninit callback will be called on
+     * allocation failure.
+     *
+     * @return 0 on success,
+     *         AVERROR code on failure (but the code will be
+     *           dropped and treated as ENOMEM by the calling code)
+     */
+    int (*preinit)(AVFilterContext *ctx);
+
+    /**
+     * Filter initialization function.
+     *
+     * This callback will be called only once during the filter lifetime, after
+     * all the options have been set, but before links between filters are
+     * established and format negotiation is done.
+     *
+     * Basic filter initialization should be done here. Filters with dynamic
+     * inputs and/or outputs should create those inputs/outputs here based on
+     * provided options. No more changes to this filter's inputs/outputs can be
+     * done after this callback.
+     *
+     * This callback must not assume that the filter links exist or frame
+     * parameters are known.
+     *
+     * @ref AVFilter.uninit "uninit" is guaranteed to be called even if
+     * initialization fails, so this callback does not have to clean up on
+     * failure.
+     *
+     * @return 0 on success, a negative AVERROR on failure
+     */
+    int (*init)(AVFilterContext *ctx);
+
+    /**
+     * Should be set instead of @ref AVFilter.init "init" by the filters that
+     * want to pass a dictionary of AVOptions to nested contexts that are
+     * allocated during init.
+     *
+     * On return, the options dict should be freed and replaced with one that
+     * contains all the options which could not be processed by this filter (or
+     * with NULL if all the options were processed).
+     *
+     * Otherwise the semantics is the same as for @ref AVFilter.init "init".
+     */
+    int (*init_dict)(AVFilterContext *ctx, AVDictionary **options);
+
+    /**
+     * Filter uninitialization function.
+     *
+     * Called only once right before the filter is freed. Should deallocate any
+     * memory held by the filter, release any buffer references, etc. It does
+     * not need to deallocate the AVFilterContext.priv memory itself.
+     *
+     * This callback may be called even if @ref AVFilter.init "init" was not
+     * called or failed, so it must be prepared to handle such a situation.
+     */
+    void (*uninit)(AVFilterContext *ctx);
+
+    /**
+     * The state of the following union is determined by formats_state.
+     * See the documentation of enum FilterFormatsState in internal.h.
+     */
+    union {
+        /**
+         * Query formats supported by the filter on its inputs and outputs.
+         *
+         * This callback is called after the filter is initialized (so the inputs
+         * and outputs are fixed), shortly before the format negotiation. This
+         * callback may be called more than once.
+         *
+         * This callback must set ::AVFilterLink's
+         * @ref AVFilterFormatsConfig.formats "outcfg.formats"
+         * on every input link and
+         * @ref AVFilterFormatsConfig.formats "incfg.formats"
+         * on every output link to a list of pixel/sample formats that the filter
+         * supports on that link.
+         * For audio links, this filter must also set
+         * @ref AVFilterFormatsConfig.samplerates "incfg.samplerates"
+         *  /
+         * @ref AVFilterFormatsConfig.samplerates "outcfg.samplerates"
+         * and @ref AVFilterFormatsConfig.channel_layouts "incfg.channel_layouts"
+         *  /
+         * @ref AVFilterFormatsConfig.channel_layouts "outcfg.channel_layouts"
+         * analogously.
+         *
+         * This callback must never be NULL if the union is in this state.
+         *
+         * @return zero on success, a negative value corresponding to an
+         * AVERROR code otherwise
+         */
+        int (*query_func)(AVFilterContext *);
+        /**
+         * A pointer to an array of admissible pixel formats delimited
+         * by AV_PIX_FMT_NONE. The generic code will use this list
+         * to indicate that this filter supports each of these pixel formats,
+         * provided that all inputs and outputs use the same pixel format.
+         *
+         * This list must never be NULL if the union is in this state.
+         * The type of all inputs and outputs of filters using this must
+         * be AVMEDIA_TYPE_VIDEO.
+         */
+        const enum AVPixelFormat *pixels_list;
+        /**
+         * Analogous to pixels, but delimited by AV_SAMPLE_FMT_NONE
+         * and restricted to filters that only have AVMEDIA_TYPE_AUDIO
+         * inputs and outputs.
+         *
+         * In addition to that the generic code will mark all inputs
+         * and all outputs as supporting all sample rates and every
+         * channel count and channel layout, as long as all inputs
+         * and outputs use the same sample rate and channel count/layout.
+         */
+        const enum AVSampleFormat *samples_list;
+        /**
+         * Equivalent to { pix_fmt, AV_PIX_FMT_NONE } as pixels_list.
+         */
+        enum AVPixelFormat  pix_fmt;
+        /**
+         * Equivalent to { sample_fmt, AV_SAMPLE_FMT_NONE } as samples_list.
+         */
+        enum AVSampleFormat sample_fmt;
+    } formats;
+
+    int priv_size;      ///< size of private data to allocate for the filter
+
+    int flags_internal; ///< Additional flags for avfilter internal use only.
+
+    /**
+     * Make the filter instance process a command.
+     *
+     * @param cmd    the command to process, for handling simplicity all commands must be alphanumeric only
+     * @param arg    the argument for the command
+     * @param res    a buffer with size res_size where the filter(s) can return a response. This must not change when the command is not supported.
+     * @param flags  if AVFILTER_CMD_FLAG_FAST is set and the command would be
+     *               time consuming then a filter should treat it like an unsupported command
+     *
+     * @returns >=0 on success otherwise an error code.
+     *          AVERROR(ENOSYS) on unsupported commands
+     */
+    int (*process_command)(AVFilterContext *, const char *cmd, const char *arg, char *res, int res_len, int flags);
+
+    /**
+     * Filter activation function.
+     *
+     * Called when any processing is needed from the filter, instead of any
+     * filter_frame and request_frame on pads.
+     *
+     * The function must examine inlinks and outlinks and perform a single
+     * step of processing. If there is nothing to do, the function must do
+     * nothing and not return an error. If more steps are or may be
+     * possible, it must use ff_filter_set_ready() to schedule another
+     * activation.
+     */
+    int (*activate)(AVFilterContext *ctx);
+} AVFilter;
+
+/**
+ * Get the number of elements in an AVFilter's inputs or outputs array.
+ */
+unsigned avfilter_filter_pad_count(const AVFilter *filter, int is_output);
+
+/**
+ * Process multiple parts of the frame concurrently.
+ */
+#define AVFILTER_THREAD_SLICE (1 << 0)
+
+typedef struct AVFilterInternal AVFilterInternal;
+
+/** An instance of a filter */
+struct AVFilterContext {
+    const AVClass *av_class;        ///< needed for av_log() and filters common options
+
+    const AVFilter *filter;         ///< the AVFilter of which this is an instance
+
+    char *name;                     ///< name of this filter instance
+
+    AVFilterPad   *input_pads;      ///< array of input pads
+    AVFilterLink **inputs;          ///< array of pointers to input links
+    unsigned    nb_inputs;          ///< number of input pads
+
+    AVFilterPad   *output_pads;     ///< array of output pads
+    AVFilterLink **outputs;         ///< array of pointers to output links
+    unsigned    nb_outputs;         ///< number of output pads
+
+    void *priv;                     ///< private data for use by the filter
+
+    struct AVFilterGraph *graph;    ///< filtergraph this filter belongs to
+
+    /**
+     * Type of multithreading being allowed/used. A combination of
+     * AVFILTER_THREAD_* flags.
+     *
+     * May be set by the caller before initializing the filter to forbid some
+     * or all kinds of multithreading for this filter. The default is allowing
+     * everything.
+     *
+     * When the filter is initialized, this field is combined using bit AND with
+     * AVFilterGraph.thread_type to get the final mask used for determining
+     * allowed threading types. I.e. a threading type needs to be set in both
+     * to be allowed.
+     *
+     * After the filter is initialized, libavfilter sets this field to the
+     * threading type that is actually used (0 for no multithreading).
+     */
+    int thread_type;
+
+    /**
+     * An opaque struct for libavfilter internal use.
+     */
+    AVFilterInternal *internal;
+
+    struct AVFilterCommand *command_queue;
+
+    char *enable_str;               ///< enable expression string
+    void *enable;                   ///< parsed expression (AVExpr*)
+    double *var_values;             ///< variable values for the enable expression
+    int is_disabled;                ///< the enabled state from the last expression evaluation
+
+    /**
+     * For filters which will create hardware frames, sets the device the
+     * filter should create them in.  All other filters will ignore this field:
+     * in particular, a filter which consumes or processes hardware frames will
+     * instead use the hw_frames_ctx field in AVFilterLink to carry the
+     * hardware context information.
+     */
+    AVBufferRef *hw_device_ctx;
+
+    /**
+     * Max number of threads allowed in this filter instance.
+     * If <= 0, its value is ignored.
+     * Overrides global number of threads set per filter graph.
+     */
+    int nb_threads;
+
+    /**
+     * Ready status of the filter.
+     * A non-0 value means that the filter needs activating;
+     * a higher value suggests a more urgent activation.
+     */
+    unsigned ready;
+
+    /**
+     * Sets the number of extra hardware frames which the filter will
+     * allocate on its output links for use in following filters or by
+     * the caller.
+     *
+     * Some hardware filters require all frames that they will use for
+     * output to be defined in advance before filtering starts.  For such
+     * filters, any hardware frame pools used for output must therefore be
+     * of fixed size.  The extra frames set here are on top of any number
+     * that the filter needs internally in order to operate normally.
+     *
+     * This field must be set before the graph containing this filter is
+     * configured.
+     */
+    int extra_hw_frames;
+};
+
+/**
+ * Lists of formats / etc. supported by an end of a link.
+ *
+ * This structure is directly part of AVFilterLink, in two copies:
+ * one for the source filter, one for the destination filter.
+
+ * These lists are used for negotiating the format to actually be used,
+ * which will be loaded into the format and channel_layout members of
+ * AVFilterLink, when chosen.
+ */
+typedef struct AVFilterFormatsConfig {
+
+    /**
+     * List of supported formats (pixel or sample).
+     */
+    AVFilterFormats *formats;
+
+    /**
+     * Lists of supported sample rates, only for audio.
+     */
+    AVFilterFormats  *samplerates;
+
+    /**
+     * Lists of supported channel layouts, only for audio.
+     */
+    AVFilterChannelLayouts  *channel_layouts;
+
+} AVFilterFormatsConfig;
+
+/**
+ * A link between two filters. This contains pointers to the source and
+ * destination filters between which this link exists, and the indexes of
+ * the pads involved. In addition, this link also contains the parameters
+ * which have been negotiated and agreed upon between the filter, such as
+ * image dimensions, format, etc.
+ *
+ * Applications must not normally access the link structure directly.
+ * Use the buffersrc and buffersink API instead.
+ * In the future, access to the header may be reserved for filters
+ * implementation.
+ */
+struct AVFilterLink {
+    AVFilterContext *src;       ///< source filter
+    AVFilterPad *srcpad;        ///< output pad on the source filter
+
+    AVFilterContext *dst;       ///< dest filter
+    AVFilterPad *dstpad;        ///< input pad on the dest filter
+
+    enum AVMediaType type;      ///< filter media type
+
+    /* These parameters apply only to video */
+    int w;                      ///< agreed upon image width
+    int h;                      ///< agreed upon image height
+    AVRational sample_aspect_ratio; ///< agreed upon sample aspect ratio
+    /* These parameters apply only to audio */
+#if FF_API_OLD_CHANNEL_LAYOUT
+    /**
+     * channel layout of current buffer (see libavutil/channel_layout.h)
+     * @deprecated use ch_layout
+     */
+    attribute_deprecated
+    uint64_t channel_layout;
+#endif
+    int sample_rate;            ///< samples per second
+
+    int format;                 ///< agreed upon media format
+
+    /**
+     * Define the time base used by the PTS of the frames/samples
+     * which will pass through this link.
+     * During the configuration stage, each filter is supposed to
+     * change only the output timebase, while the timebase of the
+     * input link is assumed to be an unchangeable property.
+     */
+    AVRational time_base;
+
+    AVChannelLayout ch_layout;  ///< channel layout of current buffer (see libavutil/channel_layout.h)
+
+    /*****************************************************************
+     * All fields below this line are not part of the public API. They
+     * may not be used outside of libavfilter and can be changed and
+     * removed at will.
+     * New public fields should be added right above.
+     *****************************************************************
+     */
+
+    /**
+     * Lists of supported formats / etc. supported by the input filter.
+     */
+    AVFilterFormatsConfig incfg;
+
+    /**
+     * Lists of supported formats / etc. supported by the output filter.
+     */
+    AVFilterFormatsConfig outcfg;
+
+    /** stage of the initialization of the link properties (dimensions, etc) */
+    enum {
+        AVLINK_UNINIT = 0,      ///< not started
+        AVLINK_STARTINIT,       ///< started, but incomplete
+        AVLINK_INIT             ///< complete
+    } init_state;
+
+    /**
+     * Graph the filter belongs to.
+     */
+    struct AVFilterGraph *graph;
+
+    /**
+     * Current timestamp of the link, as defined by the most recent
+     * frame(s), in link time_base units.
+     */
+    int64_t current_pts;
+
+    /**
+     * Current timestamp of the link, as defined by the most recent
+     * frame(s), in AV_TIME_BASE units.
+     */
+    int64_t current_pts_us;
+
+    /**
+     * Index in the age array.
+     */
+    int age_index;
+
+    /**
+     * Frame rate of the stream on the link, or 1/0 if unknown or variable;
+     * if left to 0/0, will be automatically copied from the first input
+     * of the source filter if it exists.
+     *
+     * Sources should set it to the best estimation of the real frame rate.
+     * If the source frame rate is unknown or variable, set this to 1/0.
+     * Filters should update it if necessary depending on their function.
+     * Sinks can use it to set a default output frame rate.
+     * It is similar to the r_frame_rate field in AVStream.
+     */
+    AVRational frame_rate;
+
+    /**
+     * Minimum number of samples to filter at once. If filter_frame() is
+     * called with fewer samples, it will accumulate them in fifo.
+     * This field and the related ones must not be changed after filtering
+     * has started.
+     * If 0, all related fields are ignored.
+     */
+    int min_samples;
+
+    /**
+     * Maximum number of samples to filter at once. If filter_frame() is
+     * called with more samples, it will split them.
+     */
+    int max_samples;
+
+    /**
+     * Number of past frames sent through the link.
+     */
+    int64_t frame_count_in, frame_count_out;
+
+    /**
+     * Number of past samples sent through the link.
+     */
+    int64_t sample_count_in, sample_count_out;
+
+    /**
+     * A pointer to a FFFramePool struct.
+     */
+    void *frame_pool;
+
+    /**
+     * True if a frame is currently wanted on the output of this filter.
+     * Set when ff_request_frame() is called by the output,
+     * cleared when a frame is filtered.
+     */
+    int frame_wanted_out;
+
+    /**
+     * For hwaccel pixel formats, this should be a reference to the
+     * AVHWFramesContext describing the frames.
+     */
+    AVBufferRef *hw_frames_ctx;
+
+#ifndef FF_INTERNAL_FIELDS
+
+    /**
+     * Internal structure members.
+     * The fields below this limit are internal for libavfilter's use
+     * and must in no way be accessed by applications.
+     */
+    char reserved[0xF000];
+
+#else /* FF_INTERNAL_FIELDS */
+
+    /**
+     * Queue of frames waiting to be filtered.
+     */
+    FFFrameQueue fifo;
+
+    /**
+     * If set, the source filter can not generate a frame as is.
+     * The goal is to avoid repeatedly calling the request_frame() method on
+     * the same link.
+     */
+    int frame_blocked_in;
+
+    /**
+     * Link input status.
+     * If not zero, all attempts of filter_frame will fail with the
+     * corresponding code.
+     */
+    int status_in;
+
+    /**
+     * Timestamp of the input status change.
+     */
+    int64_t status_in_pts;
+
+    /**
+     * Link output status.
+     * If not zero, all attempts of request_frame will fail with the
+     * corresponding code.
+     */
+    int status_out;
+
+#endif /* FF_INTERNAL_FIELDS */
+
+};
+
+/**
+ * Link two filters together.
+ *
+ * @param src    the source filter
+ * @param srcpad index of the output pad on the source filter
+ * @param dst    the destination filter
+ * @param dstpad index of the input pad on the destination filter
+ * @return       zero on success
+ */
+int avfilter_link(AVFilterContext *src, unsigned srcpad,
+                  AVFilterContext *dst, unsigned dstpad);
+
+/**
+ * Free the link in *link, and set its pointer to NULL.
+ */
+void avfilter_link_free(AVFilterLink **link);
+
+/**
+ * Negotiate the media format, dimensions, etc of all inputs to a filter.
+ *
+ * @param filter the filter to negotiate the properties for its inputs
+ * @return       zero on successful negotiation
+ */
+int avfilter_config_links(AVFilterContext *filter);
+
+#define AVFILTER_CMD_FLAG_ONE   1 ///< Stop once a filter understood the command (for target=all for example), fast filters are favored automatically
+#define AVFILTER_CMD_FLAG_FAST  2 ///< Only execute command when its fast (like a video out that supports contrast adjustment in hw)
+
+/**
+ * Make the filter instance process a command.
+ * It is recommended to use avfilter_graph_send_command().
+ */
+int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags);
+
+/**
+ * Iterate over all registered filters.
+ *
+ * @param opaque a pointer where libavfilter will store the iteration state. Must
+ *               point to NULL to start the iteration.
+ *
+ * @return the next registered filter or NULL when the iteration is
+ *         finished
+ */
+const AVFilter *av_filter_iterate(void **opaque);
+
+/**
+ * Get a filter definition matching the given name.
+ *
+ * @param name the filter name to find
+ * @return     the filter definition, if any matching one is registered.
+ *             NULL if none found.
+ */
+const AVFilter *avfilter_get_by_name(const char *name);
+
+
+/**
+ * Initialize a filter with the supplied parameters.
+ *
+ * @param ctx  uninitialized filter context to initialize
+ * @param args Options to initialize the filter with. This must be a
+ *             ':'-separated list of options in the 'key=value' form.
+ *             May be NULL if the options have been set directly using the
+ *             AVOptions API or there are no options that need to be set.
+ * @return 0 on success, a negative AVERROR on failure
+ */
+int avfilter_init_str(AVFilterContext *ctx, const char *args);
+
+/**
+ * Initialize a filter with the supplied dictionary of options.
+ *
+ * @param ctx     uninitialized filter context to initialize
+ * @param options An AVDictionary filled with options for this filter. On
+ *                return this parameter will be destroyed and replaced with
+ *                a dict containing options that were not found. This dictionary
+ *                must be freed by the caller.
+ *                May be NULL, then this function is equivalent to
+ *                avfilter_init_str() with the second parameter set to NULL.
+ * @return 0 on success, a negative AVERROR on failure
+ *
+ * @note This function and avfilter_init_str() do essentially the same thing,
+ * the difference is in manner in which the options are passed. It is up to the
+ * calling code to choose whichever is more preferable. The two functions also
+ * behave differently when some of the provided options are not declared as
+ * supported by the filter. In such a case, avfilter_init_str() will fail, but
+ * this function will leave those extra options in the options AVDictionary and
+ * continue as usual.
+ */
+int avfilter_init_dict(AVFilterContext *ctx, AVDictionary **options);
+
+/**
+ * Free a filter context. This will also remove the filter from its
+ * filtergraph's list of filters.
+ *
+ * @param filter the filter to free
+ */
+void avfilter_free(AVFilterContext *filter);
+
+/**
+ * Insert a filter in the middle of an existing link.
+ *
+ * @param link the link into which the filter should be inserted
+ * @param filt the filter to be inserted
+ * @param filt_srcpad_idx the input pad on the filter to connect
+ * @param filt_dstpad_idx the output pad on the filter to connect
+ * @return     zero on success
+ */
+int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
+                           unsigned filt_srcpad_idx, unsigned filt_dstpad_idx);
+
+/**
+ * @return AVClass for AVFilterContext.
+ *
+ * @see av_opt_find().
+ */
+const AVClass *avfilter_get_class(void);
+
+typedef struct AVFilterGraphInternal AVFilterGraphInternal;
+
+/**
+ * A function pointer passed to the @ref AVFilterGraph.execute callback to be
+ * executed multiple times, possibly in parallel.
+ *
+ * @param ctx the filter context the job belongs to
+ * @param arg an opaque parameter passed through from @ref
+ *            AVFilterGraph.execute
+ * @param jobnr the index of the job being executed
+ * @param nb_jobs the total number of jobs
+ *
+ * @return 0 on success, a negative AVERROR on error
+ */
+typedef int (avfilter_action_func)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
+
+/**
+ * A function executing multiple jobs, possibly in parallel.
+ *
+ * @param ctx the filter context to which the jobs belong
+ * @param func the function to be called multiple times
+ * @param arg the argument to be passed to func
+ * @param ret a nb_jobs-sized array to be filled with return values from each
+ *            invocation of func
+ * @param nb_jobs the number of jobs to execute
+ *
+ * @return 0 on success, a negative AVERROR on error
+ */
+typedef int (avfilter_execute_func)(AVFilterContext *ctx, avfilter_action_func *func,
+                                    void *arg, int *ret, int nb_jobs);
+
+typedef struct AVFilterGraph {
+    const AVClass *av_class;
+    AVFilterContext **filters;
+    unsigned nb_filters;
+
+    char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
+
+    /**
+     * Type of multithreading allowed for filters in this graph. A combination
+     * of AVFILTER_THREAD_* flags.
+     *
+     * May be set by the caller at any point, the setting will apply to all
+     * filters initialized after that. The default is allowing everything.
+     *
+     * When a filter in this graph is initialized, this field is combined using
+     * bit AND with AVFilterContext.thread_type to get the final mask used for
+     * determining allowed threading types. I.e. a threading type needs to be
+     * set in both to be allowed.
+     */
+    int thread_type;
+
+    /**
+     * Maximum number of threads used by filters in this graph. May be set by
+     * the caller before adding any filters to the filtergraph. Zero (the
+     * default) means that the number of threads is determined automatically.
+     */
+    int nb_threads;
+
+    /**
+     * Opaque object for libavfilter internal use.
+     */
+    AVFilterGraphInternal *internal;
+
+    /**
+     * Opaque user data. May be set by the caller to an arbitrary value, e.g. to
+     * be used from callbacks like @ref AVFilterGraph.execute.
+     * Libavfilter will not touch this field in any way.
+     */
+    void *opaque;
+
+    /**
+     * This callback may be set by the caller immediately after allocating the
+     * graph and before adding any filters to it, to provide a custom
+     * multithreading implementation.
+     *
+     * If set, filters with slice threading capability will call this callback
+     * to execute multiple jobs in parallel.
+     *
+     * If this field is left unset, libavfilter will use its internal
+     * implementation, which may or may not be multithreaded depending on the
+     * platform and build options.
+     */
+    avfilter_execute_func *execute;
+
+    char *aresample_swr_opts; ///< swr options to use for the auto-inserted aresample filters, Access ONLY through AVOptions
+
+    /**
+     * Private fields
+     *
+     * The following fields are for internal use only.
+     * Their type, offset, number and semantic can change without notice.
+     */
+
+    AVFilterLink **sink_links;
+    int sink_links_count;
+
+    unsigned disable_auto_convert;
+} AVFilterGraph;
+
+/**
+ * Allocate a filter graph.
+ *
+ * @return the allocated filter graph on success or NULL.
+ */
+AVFilterGraph *avfilter_graph_alloc(void);
+
+/**
+ * Create a new filter instance in a filter graph.
+ *
+ * @param graph graph in which the new filter will be used
+ * @param filter the filter to create an instance of
+ * @param name Name to give to the new instance (will be copied to
+ *             AVFilterContext.name). This may be used by the caller to identify
+ *             different filters, libavfilter itself assigns no semantics to
+ *             this parameter. May be NULL.
+ *
+ * @return the context of the newly created filter instance (note that it is
+ *         also retrievable directly through AVFilterGraph.filters or with
+ *         avfilter_graph_get_filter()) on success or NULL on failure.
+ */
+AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
+                                             const AVFilter *filter,
+                                             const char *name);
+
+/**
+ * Get a filter instance identified by instance name from graph.
+ *
+ * @param graph filter graph to search through.
+ * @param name filter instance name (should be unique in the graph).
+ * @return the pointer to the found filter instance or NULL if it
+ * cannot be found.
+ */
+AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, const char *name);
+
+/**
+ * Create and add a filter instance into an existing graph.
+ * The filter instance is created from the filter filt and inited
+ * with the parameter args. opaque is currently ignored.
+ *
+ * In case of success put in *filt_ctx the pointer to the created
+ * filter instance, otherwise set *filt_ctx to NULL.
+ *
+ * @param name the instance name to give to the created filter instance
+ * @param graph_ctx the filter graph
+ * @return a negative AVERROR error code in case of failure, a non
+ * negative value otherwise
+ */
+int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
+                                 const char *name, const char *args, void *opaque,
+                                 AVFilterGraph *graph_ctx);
+
+/**
+ * Enable or disable automatic format conversion inside the graph.
+ *
+ * Note that format conversion can still happen inside explicitly inserted
+ * scale and aresample filters.
+ *
+ * @param flags  any of the AVFILTER_AUTO_CONVERT_* constants
+ */
+void avfilter_graph_set_auto_convert(AVFilterGraph *graph, unsigned flags);
+
+enum {
+    AVFILTER_AUTO_CONVERT_ALL  =  0, /**< all automatic conversions enabled */
+    AVFILTER_AUTO_CONVERT_NONE = -1, /**< all automatic conversions disabled */
+};
+
+/**
+ * Check validity and configure all the links and formats in the graph.
+ *
+ * @param graphctx the filter graph
+ * @param log_ctx context used for logging
+ * @return >= 0 in case of success, a negative AVERROR code otherwise
+ */
+int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
+
+/**
+ * Free a graph, destroy its links, and set *graph to NULL.
+ * If *graph is NULL, do nothing.
+ */
+void avfilter_graph_free(AVFilterGraph **graph);
+
+/**
+ * A linked-list of the inputs/outputs of the filter chain.
+ *
+ * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
+ * where it is used to communicate open (unlinked) inputs and outputs from and
+ * to the caller.
+ * This struct specifies, per each not connected pad contained in the graph, the
+ * filter context and the pad index required for establishing a link.
+ */
+typedef struct AVFilterInOut {
+    /** unique name for this input/output in the list */
+    char *name;
+
+    /** filter context associated to this input/output */
+    AVFilterContext *filter_ctx;
+
+    /** index of the filt_ctx pad to use for linking */
+    int pad_idx;
+
+    /** next input/input in the list, NULL if this is the last */
+    struct AVFilterInOut *next;
+} AVFilterInOut;
+
+/**
+ * Allocate a single AVFilterInOut entry.
+ * Must be freed with avfilter_inout_free().
+ * @return allocated AVFilterInOut on success, NULL on failure.
+ */
+AVFilterInOut *avfilter_inout_alloc(void);
+
+/**
+ * Free the supplied list of AVFilterInOut and set *inout to NULL.
+ * If *inout is NULL, do nothing.
+ */
+void avfilter_inout_free(AVFilterInOut **inout);
+
+/**
+ * Add a graph described by a string to a graph.
+ *
+ * @note The caller must provide the lists of inputs and outputs,
+ * which therefore must be known before calling the function.
+ *
+ * @note The inputs parameter describes inputs of the already existing
+ * part of the graph; i.e. from the point of view of the newly created
+ * part, they are outputs. Similarly the outputs parameter describes
+ * outputs of the already existing filters, which are provided as
+ * inputs to the parsed filters.
+ *
+ * @param graph   the filter graph where to link the parsed graph context
+ * @param filters string to be parsed
+ * @param inputs  linked list to the inputs of the graph
+ * @param outputs linked list to the outputs of the graph
+ * @return zero on success, a negative AVERROR code on error
+ */
+int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
+                         AVFilterInOut *inputs, AVFilterInOut *outputs,
+                         void *log_ctx);
+
+/**
+ * Add a graph described by a string to a graph.
+ *
+ * In the graph filters description, if the input label of the first
+ * filter is not specified, "in" is assumed; if the output label of
+ * the last filter is not specified, "out" is assumed.
+ *
+ * @param graph   the filter graph where to link the parsed graph context
+ * @param filters string to be parsed
+ * @param inputs  pointer to a linked list to the inputs of the graph, may be NULL.
+ *                If non-NULL, *inputs is updated to contain the list of open inputs
+ *                after the parsing, should be freed with avfilter_inout_free().
+ * @param outputs pointer to a linked list to the outputs of the graph, may be NULL.
+ *                If non-NULL, *outputs is updated to contain the list of open outputs
+ *                after the parsing, should be freed with avfilter_inout_free().
+ * @return non negative on success, a negative AVERROR code on error
+ */
+int avfilter_graph_parse_ptr(AVFilterGraph *graph, const char *filters,
+                             AVFilterInOut **inputs, AVFilterInOut **outputs,
+                             void *log_ctx);
+
+/**
+ * Add a graph described by a string to a graph.
+ *
+ * @param[in]  graph   the filter graph where to link the parsed graph context
+ * @param[in]  filters string to be parsed
+ * @param[out] inputs  a linked list of all free (unlinked) inputs of the
+ *                     parsed graph will be returned here. It is to be freed
+ *                     by the caller using avfilter_inout_free().
+ * @param[out] outputs a linked list of all free (unlinked) outputs of the
+ *                     parsed graph will be returned here. It is to be freed by the
+ *                     caller using avfilter_inout_free().
+ * @return zero on success, a negative AVERROR code on error
+ *
+ * @note This function returns the inputs and outputs that are left
+ * unlinked after parsing the graph and the caller then deals with
+ * them.
+ * @note This function makes no reference whatsoever to already
+ * existing parts of the graph and the inputs parameter will on return
+ * contain inputs of the newly parsed part of the graph.  Analogously
+ * the outputs parameter will contain outputs of the newly created
+ * filters.
+ */
+int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
+                          AVFilterInOut **inputs,
+                          AVFilterInOut **outputs);
+
+/**
+ * Send a command to one or more filter instances.
+ *
+ * @param graph  the filter graph
+ * @param target the filter(s) to which the command should be sent
+ *               "all" sends to all filters
+ *               otherwise it can be a filter or filter instance name
+ *               which will send the command to all matching filters.
+ * @param cmd    the command to send, for handling simplicity all commands must be alphanumeric only
+ * @param arg    the argument for the command
+ * @param res    a buffer with size res_size where the filter(s) can return a response.
+ *
+ * @returns >=0 on success otherwise an error code.
+ *              AVERROR(ENOSYS) on unsupported commands
+ */
+int avfilter_graph_send_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, char *res, int res_len, int flags);
+
+/**
+ * Queue a command for one or more filter instances.
+ *
+ * @param graph  the filter graph
+ * @param target the filter(s) to which the command should be sent
+ *               "all" sends to all filters
+ *               otherwise it can be a filter or filter instance name
+ *               which will send the command to all matching filters.
+ * @param cmd    the command to sent, for handling simplicity all commands must be alphanumeric only
+ * @param arg    the argument for the command
+ * @param ts     time at which the command should be sent to the filter
+ *
+ * @note As this executes commands after this function returns, no return code
+ *       from the filter is provided, also AVFILTER_CMD_FLAG_ONE is not supported.
+ */
+int avfilter_graph_queue_command(AVFilterGraph *graph, const char *target, const char *cmd, const char *arg, int flags, double ts);
+
+
+/**
+ * Dump a graph into a human-readable string representation.
+ *
+ * @param graph    the graph to dump
+ * @param options  formatting options; currently ignored
+ * @return  a string, or NULL in case of memory allocation failure;
+ *          the string must be freed using av_free
+ */
+char *avfilter_graph_dump(AVFilterGraph *graph, const char *options);
+
+/**
+ * Request a frame on the oldest sink link.
+ *
+ * If the request returns AVERROR_EOF, try the next.
+ *
+ * Note that this function is not meant to be the sole scheduling mechanism
+ * of a filtergraph, only a convenience function to help drain a filtergraph
+ * in a balanced way under normal circumstances.
+ *
+ * Also note that AVERROR_EOF does not mean that frames did not arrive on
+ * some of the sinks during the process.
+ * When there are multiple sink links, in case the requested link
+ * returns an EOF, this may cause a filter to flush pending frames
+ * which are sent to another sink link, although unrequested.
+ *
+ * @return  the return value of ff_request_frame(),
+ *          or AVERROR_EOF if all links returned AVERROR_EOF
+ */
+int avfilter_graph_request_oldest(AVFilterGraph *graph);
+
+/**
+ * @}
+ */
+
+#endif /* AVFILTER_AVFILTER_H */