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 "avstring.h"
  26 #include "avfilter.h"
  27 #include "avfiltergraph.h"
  28
  29 #include "allfilters.h"
  30
  31 typedef struct AVFilterGraph {
  32     unsigned filter_count;
  33     AVFilterContext **filters;
  34
  35     /** fake filter to handle links to internal filters */
  36     AVFilterContext *link_filter;
  37 } GraphContext;
  38
  39 typedef struct {
  40     AVFilterContext *graph;
  41 } GraphLinkContext;
  42
  43 static int link_init(AVFilterContext *ctx, const char *args, void *opaque)
  44 {
  45     GraphLinkContext *linkctx = ctx->priv;
  46     linkctx->graph = opaque;
  47     return !opaque;
  48 }
  49
  50 /**
  51  * Given the link between the dummy filter and an internal filter whose input
  52  * is being exported outside the graph, this returns the externally visible
  53  * link
  54  */
  55 static inline AVFilterLink *get_extern_input_link(AVFilterLink *link)
  56 {
  57     GraphLinkContext *lctx = link->src->priv;
  58     return lctx->graph->inputs[link->srcpad];
  59 }
  60
  61 /** request a frame from a filter providing input to the graph */
  62 static int link_in_request_frame(AVFilterLink *link)
  63 {
  64     AVFilterLink *link2 = get_extern_input_link(link);
  65
  66     if(!link2)
  67         return -1;
  68     return avfilter_request_frame(link2);
  69 }
  70
  71 static int link_in_config_props(AVFilterLink *link)
  72 {
  73     AVFilterLink *link2 = get_extern_input_link(link);
  74     int (*config_props)(AVFilterLink *);
  75     int ret;
  76
  77     if(!link2)
  78         return -1;
  79     if(!(config_props = link2->src->output_pads[link2->srcpad].config_props))
  80         config_props = avfilter_default_config_output_link;
  81     ret = config_props(link2);
  82
  83     link->w = link2->w;
  84     link->h = link2->h;
  85
  86     return ret;
  87 }
  88
  89 /**
  90  * Given the link between the dummy filter and an internal filter whose input
  91  * is being exported outside the graph, this returns the externally visible
  92  * link
  93  */
  94 static inline AVFilterLink *get_extern_output_link(AVFilterLink *link)
  95 {
  96     GraphLinkContext *lctx = link->dst->priv;
  97     return lctx->graph->outputs[link->dstpad];
  98 }
  99
 100 static int link_out_config_props(AVFilterLink *link)
 101 {
 102     AVFilterLink *link2 = get_extern_output_link(link);
 103     int (*config_props)(AVFilterLink *);
 104
 105     if(!link2)
 106         return 0;
 107
 108     link2->w = link->w;
 109     link2->h = link->h;
 110
 111     if(!(config_props = link2->dst->input_pads[link2->dstpad].config_props))
 112         config_props = avfilter_default_config_input_link;
 113     return config_props(link2);
 114 }
 115
 116 static void link_out_start_frame(AVFilterLink *link, AVFilterPicRef *picref)
 117 {
 118     AVFilterLink *link2 = get_extern_output_link(link);
 119
 120     if(!link2)
 121         avfilter_unref_pic(picref);
 122     else
 123         avfilter_start_frame(link2, picref);
 124 }
 125
 126 static void link_out_end_frame(AVFilterLink *link)
 127 {
 128     AVFilterLink *link2 = get_extern_output_link(link);
 129
 130     if(link2)
 131         avfilter_end_frame(link2);
 132 }
 133
 134 static AVFilterPicRef *link_out_get_video_buffer(AVFilterLink *link, int perms)
 135 {
 136     AVFilterLink *link2 = get_extern_output_link(link);
 137
 138     if(!link2)
 139         return NULL;
 140     else
 141         return avfilter_get_video_buffer(link2, perms);
 142 }
 143
 144 static void link_out_draw_slice(AVFilterLink *link, int y, int height)
 145 {
 146     AVFilterLink *link2 = get_extern_output_link(link);
 147
 148     if(link2)
 149         avfilter_draw_slice(link2, y, height);
 150 }
 151
 152 /** dummy filter used to help export filters pads outside the graph */
 153 static AVFilter vf_graph_dummy =
 154 {
 155     .name      = "graph_dummy",
 156     .author    = "Bobby Bingham",
 157
 158     .priv_size = sizeof(GraphLinkContext),
 159
 160     .init      = link_init,
 161
 162     .inputs    = (AVFilterPad[]) {{ .name = NULL, }},
 163     .outputs   = (AVFilterPad[]) {{ .name = NULL, }},
 164 };
 165
 166 static AVFilterLink *get_intern_input_link(AVFilterLink *link)
 167 {
 168     GraphContext *graph = link->dst->priv;
 169     return graph->link_filter->outputs[link->dstpad];
 170 }
 171
 172 static void graph_in_start_frame(AVFilterLink *link, AVFilterPicRef *picref)
 173 {
 174     AVFilterLink *link2 = get_intern_input_link(link);
 175     if(link2)
 176         avfilter_start_frame(link2, picref);
 177 }
 178
 179 static void graph_in_end_frame(AVFilterLink *link)
 180 {
 181     AVFilterLink *link2 = get_intern_input_link(link);
 182     if(link2)
 183         avfilter_end_frame(link2);
 184 }
 185
 186 static AVFilterPicRef *graph_in_get_video_buffer(AVFilterLink *link, int perms)
 187 {
 188     AVFilterLink *link2 = get_intern_input_link(link);
 189     if(link2)
 190         return avfilter_get_video_buffer(link2, perms);
 191     return NULL;
 192 }
 193
 194 static void graph_in_draw_slice(AVFilterLink *link, int y, int height)
 195 {
 196     AVFilterLink *link2 = get_intern_input_link(link);
 197     if(link2)
 198         avfilter_draw_slice(link2, y, height);
 199 }
 200
 201 static int graph_in_config_props(AVFilterLink *link)
 202 {
 203     AVFilterLink *link2 = get_intern_input_link(link);
 204     int (*config_props)(AVFilterLink *);
 205
 206     if(!link2)
 207         return -1;
 208
 209     /* copy link properties over to the dummy internal link */
 210     link2->w = link->w;
 211     link2->h = link->h;
 212     link2->format = link->format;
 213
 214     if(!(config_props = link2->dst->input_pads[link2->dstpad].config_props))
 215         return 0;   /* FIXME? */
 216         //config_props = avfilter_default_config_input_link;
 217     return config_props(link2);
 218 }
 219
 220 static AVFilterLink *get_intern_output_link(AVFilterLink *link)
 221 {
 222     GraphContext *graph = link->src->priv;
 223     return graph->link_filter->inputs[link->srcpad];
 224 }
 225
 226 static int graph_out_request_frame(AVFilterLink *link)
 227 {
 228     AVFilterLink *link2 = get_intern_output_link(link);
 229
 230     if(link2)
 231         return avfilter_request_frame(link2);
 232     return -1;
 233 }
 234
 235 static int graph_out_config_props(AVFilterLink *link)
 236 {
 237     AVFilterLink *link2 = get_intern_output_link(link);
 238     int (*config_props)(AVFilterLink *);
 239     int ret;
 240
 241     if(!link2)
 242         return 0;
 243
 244     link2->w = link->w;
 245     link2->h = link->h;
 246     link2->format = link->format;
 247
 248     if(!(config_props = link2->src->output_pads[link2->srcpad].config_props))
 249         config_props = avfilter_default_config_output_link;
 250     ret = config_props(link2);
 251
 252     link->w = link2->w;
 253     link->h = link2->h;
 254     link->format = link2->format;
 255
 256     return ret;
 257 }
 258
 259 static int add_graph_input(AVFilterContext *gctx, AVFilterContext *filt, unsigned idx,
 260                            char *name)
 261 {
 262     GraphContext *graph = gctx->priv;
 263
 264     AVFilterPad graph_inpad =
 265     {
 266         .name             = name,
 267         .type             = AV_PAD_VIDEO,
 268         .start_frame      = graph_in_start_frame,
 269         .end_frame        = graph_in_end_frame,
 270         .get_video_buffer = graph_in_get_video_buffer,
 271         .draw_slice       = graph_in_draw_slice,
 272         .config_props     = graph_in_config_props,
 273         /* XXX */
 274     };
 275     AVFilterPad dummy_outpad =
 276     {
 277         .name          = NULL,          /* FIXME? */
 278         .type          = AV_PAD_VIDEO,
 279         .request_frame = link_in_request_frame,
 280         .config_props  = link_in_config_props,
 281     };
 282
 283     avfilter_insert_inpad (gctx, gctx->input_count, &graph_inpad);
 284     avfilter_insert_outpad(graph->link_filter, graph->link_filter->output_count,
 285                            &dummy_outpad);
 286     return avfilter_link(graph->link_filter,
 287                          graph->link_filter->output_count-1, filt, idx);
 288 }
 289
 290 static int add_graph_output(AVFilterContext *gctx, AVFilterContext *filt, unsigned idx,
 291                             char *name)
 292 {
 293     GraphContext *graph = gctx->priv;
 294
 295     AVFilterPad graph_outpad =
 296     {
 297         .name             = name,
 298         .type             = AV_PAD_VIDEO,
 299         .request_frame    = graph_out_request_frame,
 300         .config_props     = graph_out_config_props,
 301     };
 302     AVFilterPad dummy_inpad =
 303     {
 304         .name             = NULL,          /* FIXME? */
 305         .type             = AV_PAD_VIDEO,
 306         .start_frame      = link_out_start_frame,
 307         .end_frame        = link_out_end_frame,
 308         .draw_slice       = link_out_draw_slice,
 309         .get_video_buffer = link_out_get_video_buffer,
 310         .config_props     = link_out_config_props,
 311     };
 312
 313     avfilter_insert_outpad(gctx, gctx->output_count, &graph_outpad);
 314     avfilter_insert_inpad (graph->link_filter, graph->link_filter->input_count,
 315                            &dummy_inpad);
 316     return avfilter_link(filt, idx, graph->link_filter,
 317                          graph->link_filter->input_count-1);
 318 }
 319
 320 static void uninit(AVFilterContext *ctx)
 321 {
 322     GraphContext *graph = ctx->priv;
 323
 324     if(graph->link_filter) {
 325         avfilter_destroy(graph->link_filter);
 326         graph->link_filter = NULL;
 327     }
 328     for(; graph->filter_count > 0; graph->filter_count --)
 329         avfilter_destroy(graph->filters[graph->filter_count - 1]);
 330     av_freep(&graph->filters);
 331 }
 332
 333 /* TODO: insert in sorted order */
 334 void avfilter_graph_add_filter(AVFilterContext *graphctx, AVFilterContext *filter)
 335 {
 336     GraphContext *graph = graphctx->priv;
 337
 338     graph->filters = av_realloc(graph->filters,
 339                                 sizeof(AVFilterContext*) * ++graph->filter_count);
 340     graph->filters[graph->filter_count - 1] = filter;
 341 }
 342
 343 /* search intelligently, once we insert in order */
 344 AVFilterContext *avfilter_graph_get_filter(AVFilterContext *ctx, char *name)
 345 {
 346     GraphContext *graph = ctx->priv;
 347     int i;
 348
 349     if(!name)
 350         return NULL;
 351
 352     for(i = 0; i < graph->filter_count; i ++)
 353         if(graph->filters[i]->name && !strcmp(name, graph->filters[i]->name))
 354             return graph->filters[i];
 355
 356     return NULL;
 357 }
 358
 359 static int query_formats(AVFilterContext *graphctx)
 360 {
 361     GraphContext *graph = graphctx->priv;
 362     AVFilterContext *linkfilt = graph->link_filter;
 363     int i, j;
 364
 365     /* ask all the sub-filters for their supported colorspaces */
 366     for(i = 0; i < graph->filter_count; i ++) {
 367         if(graph->filters[i]->filter->query_formats)
 368             graph->filters[i]->filter->query_formats(graph->filters[i]);
 369         else
 370             avfilter_default_query_formats(graph->filters[i]);
 371     }
 372
 373     /* use these formats on our exported links */
 374     for(i = 0; i < linkfilt->input_count; i ++) {
 375         avfilter_formats_ref( linkfilt->inputs[i]->in_formats,
 376                              &linkfilt->inputs[i]->out_formats);
 377
 378         if(graphctx->outputs[i])
 379             avfilter_formats_ref( linkfilt-> inputs[i]->in_formats,
 380                                  &graphctx->outputs[i]->in_formats);
 381     }
 382     for(i = 0; i < linkfilt->output_count; i ++) {
 383         avfilter_formats_ref( linkfilt->outputs[i]->out_formats,
 384                              &linkfilt->outputs[i]->in_formats);
 385
 386         if(graphctx->inputs[i])
 387             avfilter_formats_ref( linkfilt->outputs[i]->out_formats,
 388                                  &graphctx-> inputs[i]->out_formats);
 389     }
 390
 391     /* go through and merge as many format lists as possible */
 392     for(i = 0; i < graph->filter_count; i ++) {
 393         AVFilterContext *filter = graph->filters[i];
 394
 395         for(j = 0; j < filter->input_count; j ++) {
 396             AVFilterLink *link;
 397             if(!(link = filter->inputs[j]))
 398                 continue;
 399             if(link->in_formats != link->out_formats) {
 400                 if(!avfilter_merge_formats(link->in_formats,
 401                                            link->out_formats)) {
 402                     /* couldn't merge format lists. auto-insert scale filter */
 403                     AVFilterContext *scale;
 404
 405                     if(!(scale = avfilter_open(&avfilter_vf_scale, NULL)))
 406                         return -1;
 407                     if(scale->filter->init(scale, NULL, NULL) ||
 408                        avfilter_insert_filter(link, scale, 0, 0)) {
 409                         avfilter_destroy(scale);
 410                         return -1;
 411                     }
 412
 413                     avfilter_graph_add_filter(graphctx, scale);
 414                     scale->filter->query_formats(scale);
 415                     if(avfilter_merge_formats(scale-> inputs[0]->in_formats,
 416                                               scale-> inputs[0]->out_formats) ||
 417                        avfilter_merge_formats(scale->outputs[0]->in_formats,
 418                                               scale->outputs[0]->out_formats))
 419                         return -1;
 420                 }
 421             }
 422         }
 423     }
 424
 425     return 0;
 426 }
 427
 428 static void pick_format(AVFilterLink *link)
 429 {
 430     if(!link || !link->in_formats)
 431         return;
 432
 433     link->in_formats->format_count = 1;
 434     link->format = link->in_formats->formats[0];
 435
 436     avfilter_formats_unref(&link->in_formats);
 437     avfilter_formats_unref(&link->out_formats);
 438 }
 439
 440 static void pick_formats(GraphContext *graph)
 441 {
 442     int i, j;
 443
 444     for(i = 0; i < graph->filter_count; i ++) {
 445         AVFilterContext *filter = graph->filters[i];
 446
 447         if(filter->filter == &avfilter_vf_graph     ||
 448            filter->filter == &avfilter_vf_graphfile ||
 449            filter->filter == &avfilter_vf_graphdesc)
 450             pick_formats(filter->priv);
 451
 452         for(j = 0; j < filter->input_count; j ++)
 453             pick_format(filter->inputs[j]);
 454         for(j = 0; j < filter->output_count; j ++)
 455             pick_format(filter->outputs[j]);
 456     }
 457 }
 458
 459 int avfilter_graph_config_formats(AVFilterContext *graphctx)
 460 {
 461     GraphContext *graph = graphctx->priv;
 462
 463     /* Find supported formats from sub-filters, and merge along links */
 464     if(query_formats(graphctx))
 465         return -1;
 466
 467     /* Once everything is merged, it's possible that we'll still have
 468      * multiple valid choices of colorspace. We pick the first one. */
 469     pick_formats(graph);
 470
 471     return 0;
 472 }
 473
 474 int avfilter_graph_config_links(AVFilterContext *graphctx)
 475 {
 476     GraphContext *graph = graphctx->priv;
 477     int i, j;
 478
 479     for(i = 0; i < graph->filter_count; i ++) {
 480         for(j = 0; j < graph->filters[i]->input_count; j ++) {
 481             /* ensure that graphs contained within graphs are configured */
 482             if((graph->filters[i]->filter == &avfilter_vf_graph     ||
 483                 graph->filters[i]->filter == &avfilter_vf_graphfile ||
 484                 graph->filters[i]->filter == &avfilter_vf_graphdesc) &&
 485                 avfilter_graph_config_links(graph->filters[i]))
 486                 return -1;
 487             if(avfilter_config_link(graph->filters[i]->inputs[j]))
 488                 return -1;
 489         }
 490     }
 491
 492     return 0;
 493 }
 494
 495 static AVFilterContext *create_filter_with_args(const char *filt, void *opaque)
 496 {
 497     AVFilterContext *ret;
 498     char *filter = av_strdup(filt); /* copy - don't mangle the input string */
 499     char *name, *args;
 500
 501     name = filter;
 502     if((args = strchr(filter, '='))) {
 503         /* ensure we at least have a name */
 504         if(args == filter)
 505             goto fail;
 506
 507         *args ++ = 0;
 508     }
 509
 510     av_log(NULL, AV_LOG_INFO, "creating filter \"%s\" with args \"%s\"\n",
 511            name, args ? args : "(none)");
 512
 513     if((ret = avfilter_open(avfilter_get_by_name(name), NULL))) {
 514         if(avfilter_init_filter(ret, args, opaque)) {
 515             av_log(NULL, AV_LOG_ERROR, "error initializing filter!\n");
 516             avfilter_destroy(ret);
 517             goto fail;
 518         }
 519     } else {
 520         av_log(NULL, AV_LOG_ERROR,
 521                "error creating filter \"%s\" with args \"%s\"\n",
 522                name, args ? args : "(none)");
 523     }
 524
 525     av_free(filter);
 526
 527     return ret;
 528
 529 fail:
 530     av_free(filter);
 531     return NULL;
 532 }
 533
 534 static int graph_load_chain(AVFilterContext *graphctx,
 535                               unsigned count, char **filter_list, void **opaque,
 536                               AVFilterContext **first, AVFilterContext **last)
 537 {
 538     unsigned i;
 539     AVFilterContext *filters[2] = {NULL,NULL};
 540
 541     for(i = 0; i < count; i ++) {
 542         void *op;
 543
 544         if(opaque) op = opaque[i];
 545         else       op = NULL;
 546
 547         if(!(filters[1] = create_filter_with_args(filter_list[i], op)))
 548             goto fail;
 549         if(i == 0) {
 550             if(first) *first = filters[1];
 551         } else {
 552             if(avfilter_link(filters[0], 0, filters[1], 0)) {
 553                 av_log(NULL, AV_LOG_ERROR, "error linking filters!\n");
 554                 goto fail;
 555             }
 556         }
 557         avfilter_graph_add_filter(graphctx, filters[1]);
 558         if(i == 0 && filters[1]->input_count > 0)
 559             add_graph_input(graphctx, filters[1], 0, "default");
 560         filters[0] = filters[1];
 561     }
 562
 563     if(filters[1]->output_count > 0)
 564         add_graph_output(graphctx, filters[1], 0, "default");
 565
 566     if(last) *last = filters[1];
 567     return 0;
 568
 569 fail:
 570     uninit(graphctx);
 571     if(first) *first = NULL;
 572     if(last)  *last  = NULL;
 573     return -1;
 574 }
 575
 576 static int graph_load_chain_from_string(AVFilterContext *ctx, const char *str,
 577                                         AVFilterContext **first,
 578                                         AVFilterContext **last)
 579 {
 580     int count, ret = 0;
 581     char **strings;
 582     char *filt;
 583
 584     strings    = av_malloc(sizeof(char *));
 585     strings[0] = av_strdup(str);
 586
 587     filt = strchr(strings[0], ',');
 588     for(count = 1; filt; count ++) {
 589         if(filt == strings[count-1]) {
 590             ret = -1;
 591             goto done;
 592         }
 593
 594         strings = av_realloc(strings, sizeof(char *) * (count+1));
 595         strings[count] = filt + 1;
 596         *filt = '\0';
 597         filt = strchr(strings[count], ',');
 598     }
 599
 600     ret = graph_load_chain(ctx, count, strings, NULL, first, last);
 601
 602 done:
 603     av_free(strings[0]);
 604     av_free(strings);
 605
 606     return ret;
 607 }
 608
 609 static int init(AVFilterContext *ctx, const char *args, void *opaque)
 610 {
 611     GraphContext *gctx = ctx->priv;
 612
 613     if(!(gctx->link_filter = avfilter_open(&vf_graph_dummy, NULL)))
 614         return -1;
 615     if(avfilter_init_filter(gctx->link_filter, NULL, ctx))
 616         goto fail;
 617
 618     if(!args)
 619         return 0;
 620
 621     return graph_load_chain_from_string(ctx, args, NULL, NULL);
 622
 623 fail:
 624     avfilter_destroy(gctx->link_filter);
 625     return -1;
 626 }
 627
 628 AVFilter avfilter_vf_graph =
 629 {
 630     .name      = "graph",
 631     .author    = "Bobby Bingham",
 632
 633     .priv_size = sizeof(GraphContext),
 634
 635     .init      = init,
 636     .uninit    = uninit,
 637
 638     .query_formats = query_formats,
 639
 640     .inputs    = (AVFilterPad[]) {{ .name = NULL, }},
 641     .outputs   = (AVFilterPad[]) {{ .name = NULL, }},
 642 };
 643
 644 static int graph_load_from_desc(AVFilterContext *ctx, AVFilterGraphDesc *desc)
 645 {
 646     AVFilterGraphDescFilter *curfilt;
 647     AVFilterGraphDescLink   *curlink;
 648     AVFilterGraphDescExport *curpad;
 649     AVFilterContext *filt, *filtb;
 650
 651     AVFilter *filterdef;
 652
 653     /* create all filters */
 654     for(curfilt = desc->filters; curfilt; curfilt = curfilt->next) {
 655         if(!(filterdef = avfilter_get_by_name(curfilt->filter)) ||
 656            !(filt = avfilter_open(filterdef, curfilt->name))) {
 657             av_log(ctx, AV_LOG_ERROR, "error creating filter\n");
 658             goto fail;
 659         }
 660         avfilter_graph_add_filter(ctx, filt);
 661         if(avfilter_init_filter(filt, curfilt->args, NULL)) {
 662             av_log(ctx, AV_LOG_ERROR, "error initializing filter\n");
 663             goto fail;
 664         }
 665     }
 666
 667     /* create all links */
 668     for(curlink = desc->links; curlink; curlink = curlink->next) {
 669         if(!(filt = avfilter_graph_get_filter(ctx, curlink->src))) {
 670             av_log(ctx, AV_LOG_ERROR, "link source does not exist in graph\n");
 671             goto fail;
 672         }
 673         if(!(filtb = avfilter_graph_get_filter(ctx, curlink->dst))) {
 674             av_log(ctx, AV_LOG_ERROR, "link destination does not exist in graph\n");
 675             goto fail;
 676         }
 677         if(avfilter_link(filt, curlink->srcpad, filtb, curlink->dstpad)) {
 678             av_log(ctx, AV_LOG_ERROR, "cannot create link between source and destination filters\n");
 679             goto fail;
 680         }
 681     }
 682
 683     /* export all input pads */
 684     for(curpad = desc->inputs; curpad; curpad = curpad->next) {
 685         if(!(filt = avfilter_graph_get_filter(ctx, curpad->filter))) {
 686             av_log(ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
 687             goto fail;
 688         }
 689         add_graph_input(ctx, filt, curpad->pad, curpad->name);
 690     }
 691
 692     /* export all output pads */
 693     for(curpad = desc->outputs; curpad; curpad = curpad->next) {
 694         if(!(filt = avfilter_graph_get_filter(ctx, curpad->filter))) {
 695             av_log(ctx, AV_LOG_ERROR, "filter owning exported pad does not exist\n");
 696             goto fail;
 697         }
 698         add_graph_output(ctx, filt, curpad->pad, curpad->name);
 699     }
 700
 701     return 0;
 702
 703 fail:
 704     uninit(ctx);
 705     return -1;
 706 }
 707
 708 static int init_desc(AVFilterContext *ctx, const char *args, void *opaque)
 709 {
 710     GraphContext *gctx = ctx->priv;
 711
 712     if(!opaque)
 713         return -1;
 714
 715     if(!(gctx->link_filter = avfilter_open(&vf_graph_dummy, NULL)))
 716         return -1;
 717     if(avfilter_init_filter(gctx->link_filter, NULL, ctx))
 718         goto fail;
 719
 720     return graph_load_from_desc(ctx, opaque);
 721
 722 fail:
 723     avfilter_destroy(gctx->link_filter);
 724     return -1;
 725 }
 726
 727 AVFilter avfilter_vf_graphdesc =
 728 {
 729     .name      = "graph_desc",
 730     .author    = "Bobby Bingham",
 731
 732     .priv_size = sizeof(GraphContext),
 733
 734     .init      = init_desc,
 735     .uninit    = uninit,
 736
 737     .query_formats = query_formats,
 738
 739     .inputs    = (AVFilterPad[]) {{ .name = NULL, }},
 740     .outputs   = (AVFilterPad[]) {{ .name = NULL, }},
 741 };
 742
 743 static int init_file(AVFilterContext *ctx, const char *args, void *opaque)
 744 {
 745     AVFilterGraphDesc *desc;
 746     int ret;
 747
 748     if(!args)
 749         return -1;
 750     if(!(desc = avfilter_graph_load_desc(args)))
 751         return -1;
 752
 753     ret = init_desc(ctx, NULL, desc);
 754     avfilter_graph_free_desc(desc);
 755     return ret;
 756 }
 757
 758 AVFilter avfilter_vf_graphfile =
 759 {
 760     .name      = "graph_file",
 761     .author    = "Bobby Bingham",
 762
 763     .priv_size = sizeof(GraphContext),
 764
 765     .init      = init_file,
 766     .uninit    = uninit,
 767
 768     .query_formats = query_formats,
 769
 770     .inputs    = (AVFilterPad[]) {{ .name = NULL, }},
 771     .outputs   = (AVFilterPad[]) {{ .name = NULL, }},
 772 };
 773