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     unsigned i;
  41
  42     for(i = 0; i < graph->filter_count; i ++)
  43         avfilter_destroy(graph->filters[i]);
  44     av_freep(&graph->filters);
  45 }
  46
  47 void avfilter_destroy_graph(AVFilterGraph *graph)
  48 {
  49     destroy_graph_filters(graph);
  50     av_free(graph);
  51 }
  52
  53 void avfilter_graph_add_filter(AVFilterGraph *graph, AVFilterContext *filter)
  54 {
  55     graph->filters = av_realloc(graph->filters,
  56                                 sizeof(AVFilterContext*) * ++graph->filter_count);
  57     graph->filters[graph->filter_count - 1] = filter;
  58 }
  59
  60 static AVFilterContext *create_filter_with_args(char *filter)
  61 {
  62     AVFilterContext *ret;
  63     char *name, *args;
  64
  65     name = filter;
  66     if((args = strchr(filter, '='))) {
  67         /* ensure we at least have a name */
  68         if(args == filter)
  69             return NULL;
  70
  71         *args ++ = 0;
  72     }
  73
  74     av_log(NULL, AV_LOG_INFO, "creating filter \"%s\" with args \"%s\"\n",
  75            name, args ? args : "(none)");
  76
  77     if((ret = avfilter_create_by_name(name, NULL))) {
  78         if(avfilter_init_filter(ret, args)) {
  79             av_log(NULL, AV_LOG_ERROR, "error initializing filter!\n");
  80             avfilter_destroy(ret);
  81             ret = NULL;
  82         }
  83     } else av_log(NULL, AV_LOG_ERROR, "error creating filter!\n");
  84
  85     return ret;
  86 }
  87
  88 int avfilter_graph_load_chain(AVFilterGraph *graph,
  89                               unsigned count, char **filter_list,
  90                               AVFilterContext **first, AVFilterContext **last)
  91 {
  92     unsigned i;
  93     AVFilterContext *filters[2] = {NULL,NULL};
  94
  95     for(i = 0; i < count; i ++) {
  96         if(!(filters[1] = create_filter_with_args(filter_list[i])))
  97             goto fail;
  98         if(i == 0) {
  99             if(first) *first = filters[1];
 100         } else {
 101             if(avfilter_link(filters[0], 0, filters[1], 0)) {
 102                 av_log(NULL, AV_LOG_ERROR, "error linking filters!\n");
 103                 goto fail;
 104             }
 105         }
 106         avfilter_graph_add_filter(graph, filters[1]);
 107         filters[0] = filters[1];
 108     }
 109
 110     if(last) *last = filters[1];
 111     return 0;
 112
 113 fail:
 114     destroy_graph_filters(graph);
 115     *first = *last = NULL;
 116     return -1;
 117 }
 118