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/*
* Filter graphs
* 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
* 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_AVFILTERGRAPH_H
#define AVFILTER_AVFILTERGRAPH_H

#include "avfilter.h"
#include "libavutil/log.h"

typedef struct AVFilterGraph {
const AVClass *av_class;
unsigned filter_count;
AVFilterContext **filters;

char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters

/**
* Private fields
*
* The following fields are for internal use only.
* Their type, offset, number and semantic can change without notice.
*/

unsigned disable_auto_convert;
} AVFilterGraph;

/**
* Allocate a filter graph.
*/
AVFilterGraph *avfilter_graph_alloc(void);

/**
* Get a filter instance with name name from graph.
*
* @return the pointer to the found filter instance or NULL if it
* cannot be found.
*/
AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name);

/**
* Add an existing filter instance to a filter graph.
*
* @param graphctx  the filter graph
* @param filter the filter to be added
*/

/**
* Create and add a filter instance into an existing graph.
* The filter instance is created from the filter filt and inited
* with the parameters args and opaque.
*
* In case of success put in *filt_ctx the pointer to the created
* filter instance, otherwise set *filt_ctx to NULL.
*
* @param name the instance name to give to the created filter instance
* @param graph_ctx the filter graph
* @return a negative AVERROR error code in case of failure, a non
* negative value otherwise
*/
int avfilter_graph_create_filter(AVFilterContext **filt_ctx, AVFilter *filt,
const char *name, const char *args, void *opaque,
AVFilterGraph *graph_ctx);

/**
* Enable or disable automatic format conversion inside the graph.
*
* Note that format conversion can still happen inside explicitly inserted
* scale and aconvert 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;

/** next input/input in the list, NULL if this is the last */
struct AVFilterInOut *next;
} AVFilterInOut;

/**
* Allocate a single AVFilterInOut entry.
* Must be freed with avfilter_inout_free().
* @return allocated AVFilterInOut on success, NULL on failure.
*/
AVFilterInOut *avfilter_inout_alloc(void);

/**
* Free the supplied list of AVFilterInOut and set *inout to NULL.
* If *inout is NULL, do nothing.
*/
void avfilter_inout_free(AVFilterInOut **inout);

/**
* Add a graph described by a string to a graph.
*
* @param graph   the filter graph where to link the parsed graph context
* @param filters string to be parsed
* @param inputs  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(AVFilterGraph *graph, const char *filters,
AVFilterInOut **inputs, AVFilterInOut **outputs,
void *log_ctx);

/**
* Add a graph described by a string to a graph.
*
* @param[in]  graph   the filter graph where to link the parsed graph context
* @param[in]  filters string to be parsed
* @param[out] inputs  a linked list of all free (unlinked) inputs of the
*                     parsed graph will be returned here. It is to be freed
*                     by the caller using avfilter_inout_free().
* @param[out] outputs a linked list of all free (unlinked) outputs of the
*                     parsed graph will be returned here. It is to be freed by the
*                     caller using avfilter_inout_free().
* @return zero on success, a negative AVERROR code on error
*
* @note the difference between avfilter_graph_parse2() and
* avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
* the lists of inputs and outputs, which therefore must be known before calling
* the function. On the other hand, avfilter_graph_parse2() \em returns the
* inputs and outputs that are left unlinked after parsing the graph and the
* caller then deals with them. Another difference is that in
* avfilter_graph_parse(), the inputs parameter describes inputs of the
* <em>already existing</em> part of the graph; i.e. from the point of view of
* the newly created part, they are outputs. Similarly the outputs parameter
* describes outputs of the already existing filters, which are provided as
* inputs to the parsed filters.
* avfilter_graph_parse2() takes the opposite approach -- it makes no reference
* whatsoever to already existing parts of the graph and the inputs parameter
* will on return contain inputs of the newly parsed part of the graph.
* Analogously the outputs parameter will contain outputs of the newly created
* filters.
*/
int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
AVFilterInOut **inputs,
AVFilterInOut **outputs);

/**
* 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 sent, 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 alphanummeric 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_AVFILTERGRAPH_H */