libavfilter/avfiltergraph.h

   1 /*
   2  * Filter graphs
   3  * copyright (c) 2007 Bobby Bingham
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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_AVFILTERGRAPH_H
  23 #define AVFILTER_AVFILTERGRAPH_H
  24
  25 #include "avfilter.h"
  26 #include "libavutil/log.h"
  27
  28 typedef struct AVFilterGraph {
  29     const AVClass *av_class;
  30     unsigned filter_count;
  31     AVFilterContext **filters;
  32
  33     char *scale_sws_opts; ///< sws options to use for the auto-inserted scale filters
  34     char *resample_lavr_opts;   ///< libavresample options to use for the auto-inserted resample filters
  35 } AVFilterGraph;
  36
  37 /**
  38  * Allocate a filter graph.
  39  */
  40 AVFilterGraph *avfilter_graph_alloc(void);
  41
  42 /**
  43  * Get a filter instance with name name from graph.
  44  *
  45  * @return the pointer to the found filter instance or NULL if it
  46  * cannot be found.
  47  */
  48 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name);
  49
  50 /**
  51  * Add an existing filter instance to a filter graph.
  52  *
  53  * @param graphctx  the filter graph
  54  * @param filter the filter to be added
  55  */
  56 int avfilter_graph_add_filter(AVFilterGraph *graphctx, AVFilterContext *filter);
  57
  58 /**
  59  * Create and add a filter instance into an existing graph.
  60  * The filter instance is created from the filter filt and inited
  61  * with the parameters args and opaque.
  62  *
  63  * In case of success put in *filt_ctx the pointer to the created
  64  * filter instance, otherwise set *filt_ctx to NULL.
  65  *
  66  * @param name the instance name to give to the created filter instance
  67  * @param graph_ctx the filter graph
  68  * @return a negative AVERROR error code in case of failure, a non
  69  * negative value otherwise
  70  */
  71 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, AVFilter *filt,
  72                                  const char *name, const char *args, void *opaque,
  73                                  AVFilterGraph *graph_ctx);
  74
  75 /**
  76  * Check validity and configure all the links and formats in the graph.
  77  *
  78  * @param graphctx the filter graph
  79  * @param log_ctx context used for logging
  80  * @return 0 in case of success, a negative AVERROR code otherwise
  81  */
  82 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx);
  83
  84 /**
  85  * Free a graph, destroy its links, and set *graph to NULL.
  86  * If *graph is NULL, do nothing.
  87  */
  88 void avfilter_graph_free(AVFilterGraph **graph);
  89
  90 /**
  91  * A linked-list of the inputs/outputs of the filter chain.
  92  *
  93  * This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
  94  * where it is used to communicate open (unlinked) inputs and outputs from and
  95  * to the caller.
  96  * This struct specifies, per each not connected pad contained in the graph, the
  97  * filter context and the pad index required for establishing a link.
  98  */
  99 typedef struct AVFilterInOut {
 100     /** unique name for this input/output in the list */
 101     char *name;
 102
 103     /** filter context associated to this input/output */
 104     AVFilterContext *filter_ctx;
 105
 106     /** index of the filt_ctx pad to use for linking */
 107     int pad_idx;
 108
 109     /** next input/input in the list, NULL if this is the last */
 110     struct AVFilterInOut *next;
 111 } AVFilterInOut;
 112
 113 /**
 114  * Allocate a single AVFilterInOut entry.
 115  * Must be freed with avfilter_inout_free().
 116  * @return allocated AVFilterInOut on success, NULL on failure.
 117  */
 118 AVFilterInOut *avfilter_inout_alloc(void);
 119
 120 /**
 121  * Free the supplied list of AVFilterInOut and set *inout to NULL.
 122  * If *inout is NULL, do nothing.
 123  */
 124 void avfilter_inout_free(AVFilterInOut **inout);
 125
 126 /**
 127  * Add a graph described by a string to a graph.
 128  *
 129  * @param graph   the filter graph where to link the parsed graph context
 130  * @param filters string to be parsed
 131  * @param inputs  linked list to the inputs of the graph
 132  * @param outputs linked list to the outputs of the graph
 133  * @return zero on success, a negative AVERROR code on error
 134  */
 135 int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
 136                          AVFilterInOut *inputs, AVFilterInOut *outputs,
 137                          void *log_ctx);
 138
 139 /**
 140  * Add a graph described by a string to a graph.
 141  *
 142  * @param[in]  graph   the filter graph where to link the parsed graph context
 143  * @param[in]  filters string to be parsed
 144  * @param[out] inputs  a linked list of all free (unlinked) inputs of the
 145  *                     parsed graph will be returned here. It is to be freed
 146  *                     by the caller using avfilter_inout_free().
 147  * @param[out] outputs a linked list of all free (unlinked) outputs of the
 148  *                     parsed graph will be returned here. It is to be freed by the
 149  *                     caller using avfilter_inout_free().
 150  * @return zero on success, a negative AVERROR code on error
 151  *
 152  * @note the difference between avfilter_graph_parse2() and
 153  * avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
 154  * the lists of inputs and outputs, which therefore must be known before calling
 155  * the function. On the other hand, avfilter_graph_parse2() \em returns the
 156  * inputs and outputs that are left unlinked after parsing the graph and the
 157  * caller then deals with them. Another difference is that in
 158  * avfilter_graph_parse(), the inputs parameter describes inputs of the
 159  * <em>already existing</em> part of the graph; i.e. from the point of view of
 160  * the newly created part, they are outputs. Similarly the outputs parameter
 161  * describes outputs of the already existing filters, which are provided as
 162  * inputs to the parsed filters.
 163  * avfilter_graph_parse2() takes the opposite approach -- it makes no reference
 164  * whatsoever to already existing parts of the graph and the inputs parameter
 165  * will on return contain inputs of the newly parsed part of the graph.
 166  * Analogously the outputs parameter will contain outputs of the newly created
 167  * filters.
 168  */
 169 int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
 170                           AVFilterInOut **inputs,
 171                           AVFilterInOut **outputs);
 172
 173 #endif /* AVFILTER_AVFILTERGRAPH_H */