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 "libavutil/avstring.h"
00027 #include "avfilter.h"
00028 #include "avfiltergraph.h"
00029 #include "internal.h"
00030 
00031 AVFilterGraph *avfilter_graph_alloc(void)
00032 {
00033     return av_mallocz(sizeof(AVFilterGraph));
00034 }
00035 
00036 void avfilter_graph_free(AVFilterGraph **graph)
00037 {
00038     if (!*graph)
00039         return;
00040     for (; (*graph)->filter_count > 0; (*graph)->filter_count--)
00041         avfilter_free((*graph)->filters[(*graph)->filter_count - 1]);
00042     av_freep(&(*graph)->scale_sws_opts);
00043     av_freep(&(*graph)->filters);
00044     av_freep(graph);
00045 }
00046 
00047 int avfilter_graph_add_filter(AVFilterGraph *graph, AVFilterContext *filter)
00048 {
00049     AVFilterContext **filters = av_realloc(graph->filters,
00050                                            sizeof(AVFilterContext*) * (graph->filter_count+1));
00051     if (!filters)
00052         return AVERROR(ENOMEM);
00053 
00054     graph->filters = filters;
00055     graph->filters[graph->filter_count++] = filter;
00056 
00057     return 0;
00058 }
00059 
00060 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, AVFilter *filt,
00061                                  const char *name, const char *args, void *opaque,
00062                                  AVFilterGraph *graph_ctx)
00063 {
00064     int ret;
00065 
00066     if ((ret = avfilter_open(filt_ctx, filt, name)) < 0)
00067         goto fail;
00068     if ((ret = avfilter_init_filter(*filt_ctx, args, opaque)) < 0)
00069         goto fail;
00070     if ((ret = avfilter_graph_add_filter(graph_ctx, *filt_ctx)) < 0)
00071         goto fail;
00072     return 0;
00073 
00074 fail:
00075     if (*filt_ctx)
00076         avfilter_free(*filt_ctx);
00077     *filt_ctx = NULL;
00078     return ret;
00079 }
00080 
00081 int ff_avfilter_graph_check_validity(AVFilterGraph *graph, AVClass *log_ctx)
00082 {
00083     AVFilterContext *filt;
00084     int i, j;
00085 
00086     for (i = 0; i < graph->filter_count; i++) {
00087         filt = graph->filters[i];
00088 
00089         for (j = 0; j < filt->input_count; j++) {
00090             if (!filt->inputs[j] || !filt->inputs[j]->src) {
00091                 av_log(log_ctx, AV_LOG_ERROR,
00092                        "Input pad \"%s\" for the filter \"%s\" of type \"%s\" not connected to any source\n",
00093                        filt->input_pads[j].name, filt->name, filt->filter->name);
00094                 return AVERROR(EINVAL);
00095             }
00096         }
00097 
00098         for (j = 0; j < filt->output_count; j++) {
00099             if (!filt->outputs[j] || !filt->outputs[j]->dst) {
00100                 av_log(log_ctx, AV_LOG_ERROR,
00101                        "Output pad \"%s\" for the filter \"%s\" of type \"%s\" not connected to any destination\n",
00102                        filt->output_pads[j].name, filt->name, filt->filter->name);
00103                 return AVERROR(EINVAL);
00104             }
00105         }
00106     }
00107 
00108     return 0;
00109 }
00110 
00111 int ff_avfilter_graph_config_links(AVFilterGraph *graph, AVClass *log_ctx)
00112 {
00113     AVFilterContext *filt;
00114     int i, ret;
00115 
00116     for (i=0; i < graph->filter_count; i++) {
00117         filt = graph->filters[i];
00118 
00119         if (!filt->output_count) {
00120             if ((ret = avfilter_config_links(filt)))
00121                 return ret;
00122         }
00123     }
00124 
00125     return 0;
00126 }
00127 
00128 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name)
00129 {
00130     int i;
00131 
00132     for (i = 0; i < graph->filter_count; i++)
00133         if (graph->filters[i]->name && !strcmp(name, graph->filters[i]->name))
00134             return graph->filters[i];
00135 
00136     return NULL;
00137 }
00138 
00139 static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
00140 {
00141     int i, j, ret;
00142     int scaler_count = 0;
00143     char inst_name[30];
00144 
00145     /* ask all the sub-filters for their supported media formats */
00146     for (i = 0; i < graph->filter_count; i++) {
00147         if (graph->filters[i]->filter->query_formats)
00148             graph->filters[i]->filter->query_formats(graph->filters[i]);
00149         else
00150             avfilter_default_query_formats(graph->filters[i]);
00151     }
00152 
00153     /* go through and merge as many format lists as possible */
00154     for (i = 0; i < graph->filter_count; i++) {
00155         AVFilterContext *filter = graph->filters[i];
00156 
00157         for (j = 0; j < filter->input_count; j++) {
00158             AVFilterLink *link = filter->inputs[j];
00159             if (link && link->in_formats != link->out_formats) {
00160                 if (!avfilter_merge_formats(link->in_formats,
00161                                             link->out_formats)) {
00162                     AVFilterContext *scale;
00163                     char scale_args[256];
00164                     /* couldn't merge format lists. auto-insert scale filter */
00165                     snprintf(inst_name, sizeof(inst_name), "auto-inserted scaler %d",
00166                              scaler_count++);
00167                     av_strlcpy(scale_args, "0:0", sizeof(scale_args));
00168                     if (graph->scale_sws_opts) {
00169                         av_strlcat(scale_args, ":", sizeof(scale_args));
00170                         av_strlcat(scale_args, graph->scale_sws_opts, sizeof(scale_args));
00171                     }
00172                     if ((ret = avfilter_graph_create_filter(&scale, avfilter_get_by_name("scale"),
00173                                                             inst_name, scale_args, NULL, graph)) < 0)
00174                         return ret;
00175                     if ((ret = avfilter_insert_filter(link, scale, 0, 0)) < 0)
00176                         return ret;
00177 
00178                     scale->filter->query_formats(scale);
00179                     if (((link = scale-> inputs[0]) &&
00180                          !avfilter_merge_formats(link->in_formats, link->out_formats)) ||
00181                         ((link = scale->outputs[0]) &&
00182                          !avfilter_merge_formats(link->in_formats, link->out_formats))) {
00183                         av_log(log_ctx, AV_LOG_ERROR,
00184                                "Impossible to convert between the formats supported by the filter "
00185                                "'%s' and the filter '%s'\n", link->src->name, link->dst->name);
00186                         return AVERROR(EINVAL);
00187                     }
00188                 }
00189             }
00190         }
00191     }
00192 
00193     return 0;
00194 }
00195 
00196 static void pick_format(AVFilterLink *link)
00197 {
00198     if (!link || !link->in_formats)
00199         return;
00200 
00201     link->in_formats->format_count = 1;
00202     link->format = link->in_formats->formats[0];
00203 
00204     avfilter_formats_unref(&link->in_formats);
00205     avfilter_formats_unref(&link->out_formats);
00206 }
00207 
00208 static void pick_formats(AVFilterGraph *graph)
00209 {
00210     int i, j;
00211 
00212     for (i = 0; i < graph->filter_count; i++) {
00213         AVFilterContext *filter = graph->filters[i];
00214 
00215         for (j = 0; j < filter->input_count; j++)
00216             pick_format(filter->inputs[j]);
00217         for (j = 0; j < filter->output_count; j++)
00218             pick_format(filter->outputs[j]);
00219     }
00220 }
00221 
00222 int ff_avfilter_graph_config_formats(AVFilterGraph *graph, AVClass *log_ctx)
00223 {
00224     int ret;
00225 
00226     /* find supported formats from sub-filters, and merge along links */
00227     if ((ret = query_formats(graph, log_ctx)) < 0)
00228         return ret;
00229 
00230     /* Once everything is merged, it's possible that we'll still have
00231      * multiple valid media format choices. We pick the first one. */
00232     pick_formats(graph);
00233 
00234     return 0;
00235 }
00236 
00237 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx)
00238 {
00239     int ret;
00240 
00241     if ((ret = ff_avfilter_graph_check_validity(graphctx, log_ctx)))
00242         return ret;
00243     if ((ret = ff_avfilter_graph_config_formats(graphctx, log_ctx)))
00244         return ret;
00245     if ((ret = ff_avfilter_graph_config_links(graphctx, log_ctx)))
00246         return ret;
00247 
00248     return 0;
00249 }