libavfilter/avfiltergraph.c
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00001 /*
00002  * filter graphs
00003  * Copyright (c) 2008 Vitor Sessak
00004  * Copyright (c) 2007 Bobby Bingham
00005  *
00006  * This file is part of Libav.
00007  *
00008  * Libav is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * Libav is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with Libav; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include <ctype.h>
00024 #include <string.h>
00025 
00026 #include "avfilter.h"
00027 #include "avfiltergraph.h"
00028 #include "internal.h"
00029 
00030 AVFilterGraph *avfilter_graph_alloc(void)
00031 {
00032     return av_mallocz(sizeof(AVFilterGraph));
00033 }
00034 
00035 void avfilter_graph_free(AVFilterGraph **graph)
00036 {
00037     if (!*graph)
00038         return;
00039     for (; (*graph)->filter_count > 0; (*graph)->filter_count--)
00040         avfilter_free((*graph)->filters[(*graph)->filter_count - 1]);
00041     av_freep(&(*graph)->scale_sws_opts);
00042     av_freep(&(*graph)->filters);
00043     av_freep(graph);
00044 }
00045 
00046 int avfilter_graph_add_filter(AVFilterGraph *graph, AVFilterContext *filter)
00047 {
00048     AVFilterContext **filters = av_realloc(graph->filters,
00049                                            sizeof(AVFilterContext*) * (graph->filter_count+1));
00050     if (!filters)
00051         return AVERROR(ENOMEM);
00052 
00053     graph->filters = filters;
00054     graph->filters[graph->filter_count++] = filter;
00055 
00056     return 0;
00057 }
00058 
00059 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, AVFilter *filt,
00060                                  const char *name, const char *args, void *opaque,
00061                                  AVFilterGraph *graph_ctx)
00062 {
00063     int ret;
00064 
00065     if ((ret = avfilter_open(filt_ctx, filt, name)) < 0)
00066         goto fail;
00067     if ((ret = avfilter_init_filter(*filt_ctx, args, opaque)) < 0)
00068         goto fail;
00069     if ((ret = avfilter_graph_add_filter(graph_ctx, *filt_ctx)) < 0)
00070         goto fail;
00071     return 0;
00072 
00073 fail:
00074     if (*filt_ctx)
00075         avfilter_free(*filt_ctx);
00076     *filt_ctx = NULL;
00077     return ret;
00078 }
00079 
00080 int ff_avfilter_graph_check_validity(AVFilterGraph *graph, AVClass *log_ctx)
00081 {
00082     AVFilterContext *filt;
00083     int i, j;
00084 
00085     for (i = 0; i < graph->filter_count; i++) {
00086         filt = graph->filters[i];
00087 
00088         for (j = 0; j < filt->input_count; j++) {
00089             if (!filt->inputs[j] || !filt->inputs[j]->src) {
00090                 av_log(log_ctx, AV_LOG_ERROR,
00091                        "Input pad \"%s\" for the filter \"%s\" of type \"%s\" not connected to any source\n",
00092                        filt->input_pads[j].name, filt->name, filt->filter->name);
00093                 return AVERROR(EINVAL);
00094             }
00095         }
00096 
00097         for (j = 0; j < filt->output_count; j++) {
00098             if (!filt->outputs[j] || !filt->outputs[j]->dst) {
00099                 av_log(log_ctx, AV_LOG_ERROR,
00100                        "Output pad \"%s\" for the filter \"%s\" of type \"%s\" not connected to any destination\n",
00101                        filt->output_pads[j].name, filt->name, filt->filter->name);
00102                 return AVERROR(EINVAL);
00103             }
00104         }
00105     }
00106 
00107     return 0;
00108 }
00109 
00110 int ff_avfilter_graph_config_links(AVFilterGraph *graph, AVClass *log_ctx)
00111 {
00112     AVFilterContext *filt;
00113     int i, ret;
00114 
00115     for (i=0; i < graph->filter_count; i++) {
00116         filt = graph->filters[i];
00117 
00118         if (!filt->output_count) {
00119             if ((ret = avfilter_config_links(filt)))
00120                 return ret;
00121         }
00122     }
00123 
00124     return 0;
00125 }
00126 
00127 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name)
00128 {
00129     int i;
00130 
00131     for (i = 0; i < graph->filter_count; i++)
00132         if (graph->filters[i]->name && !strcmp(name, graph->filters[i]->name))
00133             return graph->filters[i];
00134 
00135     return NULL;
00136 }
00137 
00138 static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
00139 {
00140     int i, j, ret;
00141     int scaler_count = 0;
00142     char inst_name[30];
00143 
00144     /* ask all the sub-filters for their supported media formats */
00145     for (i = 0; i < graph->filter_count; i++) {
00146         if (graph->filters[i]->filter->query_formats)
00147             graph->filters[i]->filter->query_formats(graph->filters[i]);
00148         else
00149             avfilter_default_query_formats(graph->filters[i]);
00150     }
00151 
00152     /* go through and merge as many format lists as possible */
00153     for (i = 0; i < graph->filter_count; i++) {
00154         AVFilterContext *filter = graph->filters[i];
00155 
00156         for (j = 0; j < filter->input_count; j++) {
00157             AVFilterLink *link = filter->inputs[j];
00158             if (link && link->in_formats != link->out_formats) {
00159                 if (!avfilter_merge_formats(link->in_formats,
00160                                             link->out_formats)) {
00161                     AVFilterContext *scale;
00162                     char scale_args[256];
00163                     /* couldn't merge format lists. auto-insert scale filter */
00164                     snprintf(inst_name, sizeof(inst_name), "auto-inserted scaler %d",
00165                              scaler_count++);
00166                     snprintf(scale_args, sizeof(scale_args), "0:0:%s", graph->scale_sws_opts);
00167                     if ((ret = avfilter_graph_create_filter(&scale, avfilter_get_by_name("scale"),
00168                                                             inst_name, scale_args, NULL, graph)) < 0)
00169                         return ret;
00170                     if ((ret = avfilter_insert_filter(link, scale, 0, 0)) < 0)
00171                         return ret;
00172 
00173                     scale->filter->query_formats(scale);
00174                     if (((link = scale-> inputs[0]) &&
00175                          !avfilter_merge_formats(link->in_formats, link->out_formats)) ||
00176                         ((link = scale->outputs[0]) &&
00177                          !avfilter_merge_formats(link->in_formats, link->out_formats))) {
00178                         av_log(log_ctx, AV_LOG_ERROR,
00179                                "Impossible to convert between the formats supported by the filter "
00180                                "'%s' and the filter '%s'\n", link->src->name, link->dst->name);
00181                         return AVERROR(EINVAL);
00182                     }
00183                 }
00184             }
00185         }
00186     }
00187 
00188     return 0;
00189 }
00190 
00191 static void pick_format(AVFilterLink *link)
00192 {
00193     if (!link || !link->in_formats)
00194         return;
00195 
00196     link->in_formats->format_count = 1;
00197     link->format = link->in_formats->formats[0];
00198 
00199     avfilter_formats_unref(&link->in_formats);
00200     avfilter_formats_unref(&link->out_formats);
00201 }
00202 
00203 static void pick_formats(AVFilterGraph *graph)
00204 {
00205     int i, j;
00206 
00207     for (i = 0; i < graph->filter_count; i++) {
00208         AVFilterContext *filter = graph->filters[i];
00209 
00210         for (j = 0; j < filter->input_count; j++)
00211             pick_format(filter->inputs[j]);
00212         for (j = 0; j < filter->output_count; j++)
00213             pick_format(filter->outputs[j]);
00214     }
00215 }
00216 
00217 int ff_avfilter_graph_config_formats(AVFilterGraph *graph, AVClass *log_ctx)
00218 {
00219     int ret;
00220 
00221     /* find supported formats from sub-filters, and merge along links */
00222     if ((ret = query_formats(graph, log_ctx)) < 0)
00223         return ret;
00224 
00225     /* Once everything is merged, it's possible that we'll still have
00226      * multiple valid media format choices. We pick the first one. */
00227     pick_formats(graph);
00228 
00229     return 0;
00230 }
00231 
00232 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx)
00233 {
00234     int ret;
00235 
00236     if ((ret = ff_avfilter_graph_check_validity(graphctx, log_ctx)))
00237         return ret;
00238     if ((ret = ff_avfilter_graph_config_formats(graphctx, log_ctx)))
00239         return ret;
00240     if ((ret = ff_avfilter_graph_config_links(graphctx, log_ctx)))
00241         return ret;
00242 
00243     return 0;
00244 }