libavfilter/avfiltergraph.c

   1 /*
   2  * Filter graphs
   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 #include <string.h>
  23 #include <stddef.h>
  24
  25 #include "avfilter.h"
  26 #include "avfiltergraph.h"
  27
  28 struct AVFilterGraph {
  29     unsigned filter_count;
  30     AVFilterContext **filters;
  31 };
  32
  33 AVFilterGraph *avfilter_create_graph(void)
  34 {
  35     return av_mallocz(sizeof(AVFilterGraph));
  36 }
  37
  38 static void destroy_graph_filters(AVFilterGraph *graph)
  39 {
  40     for(; graph->filter_count > 0; graph->filter_count --)
  41         avfilter_destroy(graph->filters[graph->filter_count - 1]);
  42     av_freep(&graph->filters);
  43 }
  44
  45 void avfilter_destroy_graph(AVFilterGraph *graph)
  46 {
  47     destroy_graph_filters(graph);
  48     av_free(graph);
  49 }
  50
  51 void avfilter_graph_add_filter(AVFilterGraph *graph, AVFilterContext *filter)
  52 {
  53     graph->filters = av_realloc(graph->filters,
  54                                 sizeof(AVFilterContext*) * ++graph->filter_count);
  55     graph->filters[graph->filter_count - 1] = filter;
  56 }
  57
  58 static AVFilterContext *create_filter_with_args(char *filter)
  59 {
  60     AVFilterContext *ret;
  61     char *name, *args;
  62
  63     name = filter;
  64     if((args = strchr(filter, '='))) {
  65         /* ensure we at least have a name */
  66         if(args == filter)
  67             return NULL;
  68
  69         *args ++ = 0;
  70     }
  71
  72     av_log(NULL, AV_LOG_INFO, "creating filter \"%s\" with args \"%s\"\n",
  73            name, args ? args : "(none)");
  74
  75     if((ret = avfilter_create_by_name(name, NULL))) {
  76         if(avfilter_init_filter(ret, args)) {
  77             av_log(NULL, AV_LOG_ERROR, "error initializing filter!\n");
  78             avfilter_destroy(ret);
  79             ret = NULL;
  80         }
  81     } else av_log(NULL, AV_LOG_ERROR, "error creating filter!\n");
  82
  83     return ret;
  84 }
  85
  86 int avfilter_graph_load_chain(AVFilterGraph *graph,
  87                               unsigned count, char **filter_list,
  88                               AVFilterContext **first, AVFilterContext **last)
  89 {
  90     unsigned i;
  91     AVFilterContext *filters[2] = {NULL,NULL};
  92
  93     for(i = 0; i < count; i ++) {
  94         if(!(filters[1] = create_filter_with_args(filter_list[i])))
  95             goto fail;
  96         if(i == 0) {
  97             if(first) *first = filters[1];
  98         } else {
  99             if(avfilter_link(filters[0], 0, filters[1], 0)) {
 100                 av_log(NULL, AV_LOG_ERROR, "error linking filters!\n");
 101                 goto fail;
 102             }
 103         }
 104         avfilter_graph_add_filter(graph, filters[1]);
 105         filters[0] = filters[1];
 106     }
 107
 108     if(last) *last = filters[1];
 109     return 0;
 110
 111 fail:
 112     destroy_graph_filters(graph);
 113     if(first) *first = NULL;
 114     if(last)  *last  = NULL;
 115     return -1;
 116 }
 117