git.sesse.net Git - ffmpeg/blob - libavfilter/avfiltergraph.c

   1 /*
   2  * filter graphs
   3  * Copyright (c) 2008 Vitor Sessak
   4  * Copyright (c) 2007 Bobby Bingham
   5  *
   6  * This file is part of Libav.
   7  *
   8  * Libav is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * Libav is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with Libav; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "config.h"
  24
  25 #include <string.h>
  26
  27 #include "libavutil/avassert.h"
  28 #include "libavutil/avstring.h"
  29 #include "libavutil/channel_layout.h"
  30 #include "libavutil/common.h"
  31 #include "libavutil/internal.h"
  32 #include "libavutil/log.h"
  33 #include "libavutil/opt.h"
  34
  35 #include "avfilter.h"
  36 #include "formats.h"
  37 #include "internal.h"
  38 #include "thread.h"
  39
  40 #define OFFSET(x) offsetof(AVFilterGraph, x)
  41 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM
  42 static const AVOption filtergraph_options[] = {
  43     { "thread_type", "Allowed thread types", OFFSET(thread_type), AV_OPT_TYPE_FLAGS,
  44         { .i64 = AVFILTER_THREAD_SLICE }, 0, INT_MAX, FLAGS, "thread_type" },
  45         { "slice", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AVFILTER_THREAD_SLICE }, .flags = FLAGS, .unit = "thread_type" },
  46     { "threads",     "Maximum number of threads", OFFSET(nb_threads),
  47         AV_OPT_TYPE_INT,   { .i64 = 0 }, 0, INT_MAX, FLAGS },
  48     { NULL },
  49 };
  50
  51 static const AVClass filtergraph_class = {
  52     .class_name = "AVFilterGraph",
  53     .item_name  = av_default_item_name,
  54     .version    = LIBAVUTIL_VERSION_INT,
  55     .option     = filtergraph_options,
  56 };
  57
  58 #if !HAVE_THREADS
  59 void ff_graph_thread_free(AVFilterGraph *graph)
  60 {
  61 }
  62
  63 int ff_graph_thread_init(AVFilterGraph *graph)
  64 {
  65     graph->thread_type = 0;
  66     graph->nb_threads  = 1;
  67     return 0;
  68 }
  69 #endif
  70
  71 AVFilterGraph *avfilter_graph_alloc(void)
  72 {
  73     AVFilterGraph *ret = av_mallocz(sizeof(*ret));
  74     if (!ret)
  75         return NULL;
  76
  77     ret->internal = av_mallocz(sizeof(*ret->internal));
  78     if (!ret->internal) {
  79         av_freep(&ret);
  80         return NULL;
  81     }
  82
  83     ret->av_class = &filtergraph_class;
  84     av_opt_set_defaults(ret);
  85
  86     return ret;
  87 }
  88
  89 void ff_filter_graph_remove_filter(AVFilterGraph *graph, AVFilterContext *filter)
  90 {
  91     int i;
  92     for (i = 0; i < graph->nb_filters; i++) {
  93         if (graph->filters[i] == filter) {
  94             FFSWAP(AVFilterContext*, graph->filters[i],
  95                    graph->filters[graph->nb_filters - 1]);
  96             graph->nb_filters--;
  97             return;
  98         }
  99     }
 100 }
 101
 102 void avfilter_graph_free(AVFilterGraph **graph)
 103 {
 104     if (!*graph)
 105         return;
 106
 107     while ((*graph)->nb_filters)
 108         avfilter_free((*graph)->filters[0]);
 109
 110     ff_graph_thread_free(*graph);
 111
 112     av_freep(&(*graph)->scale_sws_opts);
 113     av_freep(&(*graph)->resample_lavr_opts);
 114     av_freep(&(*graph)->filters);
 115     av_freep(&(*graph)->internal);
 116     av_freep(graph);
 117 }
 118
 119 #if FF_API_AVFILTER_OPEN
 120 int avfilter_graph_add_filter(AVFilterGraph *graph, AVFilterContext *filter)
 121 {
 122     AVFilterContext **filters = av_realloc(graph->filters,
 123                                            sizeof(*filters) * (graph->nb_filters + 1));
 124     if (!filters)
 125         return AVERROR(ENOMEM);
 126
 127     graph->filters = filters;
 128     graph->filters[graph->nb_filters++] = filter;
 129
 130 #if FF_API_FOO_COUNT
 131 FF_DISABLE_DEPRECATION_WARNINGS
 132     graph->filter_count = graph->nb_filters;
 133 FF_ENABLE_DEPRECATION_WARNINGS
 134 #endif
 135
 136     filter->graph = graph;
 137
 138     return 0;
 139 }
 140 #endif
 141
 142 int avfilter_graph_create_filter(AVFilterContext **filt_ctx, const AVFilter *filt,
 143                                  const char *name, const char *args, void *opaque,
 144                                  AVFilterGraph *graph_ctx)
 145 {
 146     int ret;
 147
 148     *filt_ctx = avfilter_graph_alloc_filter(graph_ctx, filt, name);
 149     if (!*filt_ctx)
 150         return AVERROR(ENOMEM);
 151
 152     ret = avfilter_init_str(*filt_ctx, args);
 153     if (ret < 0)
 154         goto fail;
 155
 156     return 0;
 157
 158 fail:
 159     if (*filt_ctx)
 160         avfilter_free(*filt_ctx);
 161     *filt_ctx = NULL;
 162     return ret;
 163 }
 164
 165 AVFilterContext *avfilter_graph_alloc_filter(AVFilterGraph *graph,
 166                                              const AVFilter *filter,
 167                                              const char *name)
 168 {
 169     AVFilterContext **filters, *s;
 170
 171     if (graph->thread_type && !graph->internal->thread) {
 172         int ret = ff_graph_thread_init(graph);
 173         if (ret < 0) {
 174             av_log(graph, AV_LOG_ERROR, "Error initializing threading.\n");
 175             return NULL;
 176         }
 177     }
 178
 179     s = ff_filter_alloc(filter, name);
 180     if (!s)
 181         return NULL;
 182
 183     filters = av_realloc(graph->filters, sizeof(*filters) * (graph->nb_filters + 1));
 184     if (!filters) {
 185         avfilter_free(s);
 186         return NULL;
 187     }
 188
 189     graph->filters = filters;
 190     graph->filters[graph->nb_filters++] = s;
 191
 192 #if FF_API_FOO_COUNT
 193 FF_DISABLE_DEPRECATION_WARNINGS
 194     graph->filter_count = graph->nb_filters;
 195 FF_ENABLE_DEPRECATION_WARNINGS
 196 #endif
 197
 198     s->graph = graph;
 199
 200     return s;
 201 }
 202
 203 /**
 204  * Check for the validity of graph.
 205  *
 206  * A graph is considered valid if all its input and output pads are
 207  * connected.
 208  *
 209  * @return 0 in case of success, a negative value otherwise
 210  */
 211 static int graph_check_validity(AVFilterGraph *graph, AVClass *log_ctx)
 212 {
 213     AVFilterContext *filt;
 214     int i, j;
 215
 216     for (i = 0; i < graph->nb_filters; i++) {
 217         filt = graph->filters[i];
 218
 219         for (j = 0; j < filt->nb_inputs; j++) {
 220             if (!filt->inputs[j] || !filt->inputs[j]->src) {
 221                 av_log(log_ctx, AV_LOG_ERROR,
 222                        "Input pad \"%s\" for the filter \"%s\" of type \"%s\" not connected to any source\n",
 223                        filt->input_pads[j].name, filt->name, filt->filter->name);
 224                 return AVERROR(EINVAL);
 225             }
 226         }
 227
 228         for (j = 0; j < filt->nb_outputs; j++) {
 229             if (!filt->outputs[j] || !filt->outputs[j]->dst) {
 230                 av_log(log_ctx, AV_LOG_ERROR,
 231                        "Output pad \"%s\" for the filter \"%s\" of type \"%s\" not connected to any destination\n",
 232                        filt->output_pads[j].name, filt->name, filt->filter->name);
 233                 return AVERROR(EINVAL);
 234             }
 235         }
 236     }
 237
 238     return 0;
 239 }
 240
 241 /**
 242  * Configure all the links of graphctx.
 243  *
 244  * @return 0 in case of success, a negative value otherwise
 245  */
 246 static int graph_config_links(AVFilterGraph *graph, AVClass *log_ctx)
 247 {
 248     AVFilterContext *filt;
 249     int i, ret;
 250
 251     for (i = 0; i < graph->nb_filters; i++) {
 252         filt = graph->filters[i];
 253
 254         if (!filt->nb_outputs) {
 255             if ((ret = avfilter_config_links(filt)))
 256                 return ret;
 257         }
 258     }
 259
 260     return 0;
 261 }
 262
 263 AVFilterContext *avfilter_graph_get_filter(AVFilterGraph *graph, char *name)
 264 {
 265     int i;
 266
 267     for (i = 0; i < graph->nb_filters; i++)
 268         if (graph->filters[i]->name && !strcmp(name, graph->filters[i]->name))
 269             return graph->filters[i];
 270
 271     return NULL;
 272 }
 273
 274 static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
 275 {
 276     int i, j, ret;
 277     int scaler_count = 0, resampler_count = 0;
 278
 279     /* ask all the sub-filters for their supported media formats */
 280     for (i = 0; i < graph->nb_filters; i++) {
 281         if (graph->filters[i]->filter->query_formats)
 282             graph->filters[i]->filter->query_formats(graph->filters[i]);
 283         else
 284             ff_default_query_formats(graph->filters[i]);
 285     }
 286
 287     /* go through and merge as many format lists as possible */
 288     for (i = 0; i < graph->nb_filters; i++) {
 289         AVFilterContext *filter = graph->filters[i];
 290
 291         for (j = 0; j < filter->nb_inputs; j++) {
 292             AVFilterLink *link = filter->inputs[j];
 293             int convert_needed = 0;
 294
 295             if (!link)
 296                 continue;
 297
 298             if (link->in_formats != link->out_formats &&
 299                 !ff_merge_formats(link->in_formats,
 300                                         link->out_formats))
 301                 convert_needed = 1;
 302             if (link->type == AVMEDIA_TYPE_AUDIO) {
 303                 if (link->in_channel_layouts != link->out_channel_layouts &&
 304                     !ff_merge_channel_layouts(link->in_channel_layouts,
 305                                               link->out_channel_layouts))
 306                     convert_needed = 1;
 307                 if (link->in_samplerates != link->out_samplerates &&
 308                     !ff_merge_samplerates(link->in_samplerates,
 309                                           link->out_samplerates))
 310                     convert_needed = 1;
 311             }
 312
 313             if (convert_needed) {
 314                 AVFilterContext *convert;
 315                 AVFilter *filter;
 316                 AVFilterLink *inlink, *outlink;
 317                 char scale_args[256];
 318                 char inst_name[30];
 319
 320                 /* couldn't merge format lists. auto-insert conversion filter */
 321                 switch (link->type) {
 322                 case AVMEDIA_TYPE_VIDEO:
 323                     if (!(filter = avfilter_get_by_name("scale"))) {
 324                         av_log(log_ctx, AV_LOG_ERROR, "'scale' filter "
 325                                "not present, cannot convert pixel formats.\n");
 326                         return AVERROR(EINVAL);
 327                     }
 328
 329                     snprintf(inst_name, sizeof(inst_name), "auto-inserted scaler %d",
 330                              scaler_count++);
 331
 332                     if ((ret = avfilter_graph_create_filter(&convert, filter,
 333                                                             inst_name, graph->scale_sws_opts, NULL,
 334                                                             graph)) < 0)
 335                         return ret;
 336                     break;
 337                 case AVMEDIA_TYPE_AUDIO:
 338                     if (!(filter = avfilter_get_by_name("resample"))) {
 339                         av_log(log_ctx, AV_LOG_ERROR, "'resample' filter "
 340                                "not present, cannot convert audio formats.\n");
 341                         return AVERROR(EINVAL);
 342                     }
 343
 344                     snprintf(inst_name, sizeof(inst_name), "auto-inserted resampler %d",
 345                              resampler_count++);
 346                     scale_args[0] = '\0';
 347                     if (graph->resample_lavr_opts)
 348                         snprintf(scale_args, sizeof(scale_args), "%s",
 349                                  graph->resample_lavr_opts);
 350                     if ((ret = avfilter_graph_create_filter(&convert, filter,
 351                                                             inst_name, scale_args,
 352                                                             NULL, graph)) < 0)
 353                         return ret;
 354                     break;
 355                 default:
 356                     return AVERROR(EINVAL);
 357                 }
 358
 359                 if ((ret = avfilter_insert_filter(link, convert, 0, 0)) < 0)
 360                     return ret;
 361
 362                 convert->filter->query_formats(convert);
 363                 inlink  = convert->inputs[0];
 364                 outlink = convert->outputs[0];
 365                 if (!ff_merge_formats( inlink->in_formats,  inlink->out_formats) ||
 366                     !ff_merge_formats(outlink->in_formats, outlink->out_formats))
 367                     ret |= AVERROR(ENOSYS);
 368                 if (inlink->type == AVMEDIA_TYPE_AUDIO &&
 369                     (!ff_merge_samplerates(inlink->in_samplerates,
 370                                            inlink->out_samplerates) ||
 371                      !ff_merge_channel_layouts(inlink->in_channel_layouts,
 372                                                inlink->out_channel_layouts)))
 373                     ret |= AVERROR(ENOSYS);
 374                 if (outlink->type == AVMEDIA_TYPE_AUDIO &&
 375                     (!ff_merge_samplerates(outlink->in_samplerates,
 376                                            outlink->out_samplerates) ||
 377                      !ff_merge_channel_layouts(outlink->in_channel_layouts,
 378                                                outlink->out_channel_layouts)))
 379                     ret |= AVERROR(ENOSYS);
 380
 381                 if (ret < 0) {
 382                     av_log(log_ctx, AV_LOG_ERROR,
 383                            "Impossible to convert between the formats supported by the filter "
 384                            "'%s' and the filter '%s'\n", link->src->name, link->dst->name);
 385                     return ret;
 386                 }
 387             }
 388         }
 389     }
 390
 391     return 0;
 392 }
 393
 394 static int pick_format(AVFilterLink *link)
 395 {
 396     if (!link || !link->in_formats)
 397         return 0;
 398
 399     link->in_formats->nb_formats = 1;
 400     link->format = link->in_formats->formats[0];
 401
 402     if (link->type == AVMEDIA_TYPE_AUDIO) {
 403         if (!link->in_samplerates->nb_formats) {
 404             av_log(link->src, AV_LOG_ERROR, "Cannot select sample rate for"
 405                    " the link between filters %s and %s.\n", link->src->name,
 406                    link->dst->name);
 407             return AVERROR(EINVAL);
 408         }
 409         link->in_samplerates->nb_formats = 1;
 410         link->sample_rate = link->in_samplerates->formats[0];
 411
 412         if (!link->in_channel_layouts->nb_channel_layouts) {
 413             av_log(link->src, AV_LOG_ERROR, "Cannot select channel layout for"
 414                    "the link between filters %s and %s.\n", link->src->name,
 415                    link->dst->name);
 416             return AVERROR(EINVAL);
 417         }
 418         link->in_channel_layouts->nb_channel_layouts = 1;
 419         link->channel_layout = link->in_channel_layouts->channel_layouts[0];
 420     }
 421
 422     ff_formats_unref(&link->in_formats);
 423     ff_formats_unref(&link->out_formats);
 424     ff_formats_unref(&link->in_samplerates);
 425     ff_formats_unref(&link->out_samplerates);
 426     ff_channel_layouts_unref(&link->in_channel_layouts);
 427     ff_channel_layouts_unref(&link->out_channel_layouts);
 428
 429     return 0;
 430 }
 431
 432 #define REDUCE_FORMATS(fmt_type, list_type, list, var, nb, add_format) \
 433 do {                                                                   \
 434     for (i = 0; i < filter->nb_inputs; i++) {                          \
 435         AVFilterLink *link = filter->inputs[i];                        \
 436         fmt_type fmt;                                                  \
 437                                                                        \
 438         if (!link->out_ ## list || link->out_ ## list->nb != 1)        \
 439             continue;                                                  \
 440         fmt = link->out_ ## list->var[0];                              \
 441                                                                        \
 442         for (j = 0; j < filter->nb_outputs; j++) {                     \
 443             AVFilterLink *out_link = filter->outputs[j];               \
 444             list_type *fmts;                                           \
 445                                                                        \
 446             if (link->type != out_link->type ||                        \
 447                 out_link->in_ ## list->nb == 1)                        \
 448                 continue;                                              \
 449             fmts = out_link->in_ ## list;                              \
 450                                                                        \
 451             if (!out_link->in_ ## list->nb) {                          \
 452                 add_format(&out_link->in_ ##list, fmt);                \
 453                 break;                                                 \
 454             }                                                          \
 455                                                                        \
 456             for (k = 0; k < out_link->in_ ## list->nb; k++)            \
 457                 if (fmts->var[k] == fmt) {                             \
 458                     fmts->var[0]  = fmt;                               \
 459                     fmts->nb = 1;                                      \
 460                     ret = 1;                                           \
 461                     break;                                             \
 462                 }                                                      \
 463         }                                                              \
 464     }                                                                  \
 465 } while (0)
 466
 467 static int reduce_formats_on_filter(AVFilterContext *filter)
 468 {
 469     int i, j, k, ret = 0;
 470
 471     REDUCE_FORMATS(int,      AVFilterFormats,        formats,         formats,
 472                    nb_formats, ff_add_format);
 473     REDUCE_FORMATS(int,      AVFilterFormats,        samplerates,     formats,
 474                    nb_formats, ff_add_format);
 475     REDUCE_FORMATS(uint64_t, AVFilterChannelLayouts, channel_layouts,
 476                    channel_layouts, nb_channel_layouts, ff_add_channel_layout);
 477
 478     return ret;
 479 }
 480
 481 static void reduce_formats(AVFilterGraph *graph)
 482 {
 483     int i, reduced;
 484
 485     do {
 486         reduced = 0;
 487
 488         for (i = 0; i < graph->nb_filters; i++)
 489             reduced |= reduce_formats_on_filter(graph->filters[i]);
 490     } while (reduced);
 491 }
 492
 493 static void swap_samplerates_on_filter(AVFilterContext *filter)
 494 {
 495     AVFilterLink *link = NULL;
 496     int sample_rate;
 497     int i, j;
 498
 499     for (i = 0; i < filter->nb_inputs; i++) {
 500         link = filter->inputs[i];
 501
 502         if (link->type == AVMEDIA_TYPE_AUDIO &&
 503             link->out_samplerates->nb_formats== 1)
 504             break;
 505     }
 506     if (i == filter->nb_inputs)
 507         return;
 508
 509     sample_rate = link->out_samplerates->formats[0];
 510
 511     for (i = 0; i < filter->nb_outputs; i++) {
 512         AVFilterLink *outlink = filter->outputs[i];
 513         int best_idx, best_diff = INT_MAX;
 514
 515         if (outlink->type != AVMEDIA_TYPE_AUDIO ||
 516             outlink->in_samplerates->nb_formats < 2)
 517             continue;
 518
 519         for (j = 0; j < outlink->in_samplerates->nb_formats; j++) {
 520             int diff = abs(sample_rate - outlink->in_samplerates->formats[j]);
 521
 522             if (diff < best_diff) {
 523                 best_diff = diff;
 524                 best_idx  = j;
 525             }
 526         }
 527         FFSWAP(int, outlink->in_samplerates->formats[0],
 528                outlink->in_samplerates->formats[best_idx]);
 529     }
 530 }
 531
 532 static void swap_samplerates(AVFilterGraph *graph)
 533 {
 534     int i;
 535
 536     for (i = 0; i < graph->nb_filters; i++)
 537         swap_samplerates_on_filter(graph->filters[i]);
 538 }
 539
 540 #define CH_CENTER_PAIR (AV_CH_FRONT_LEFT_OF_CENTER | AV_CH_FRONT_RIGHT_OF_CENTER)
 541 #define CH_FRONT_PAIR  (AV_CH_FRONT_LEFT           | AV_CH_FRONT_RIGHT)
 542 #define CH_STEREO_PAIR (AV_CH_STEREO_LEFT          | AV_CH_STEREO_RIGHT)
 543 #define CH_WIDE_PAIR   (AV_CH_WIDE_LEFT            | AV_CH_WIDE_RIGHT)
 544 #define CH_SIDE_PAIR   (AV_CH_SIDE_LEFT            | AV_CH_SIDE_RIGHT)
 545 #define CH_DIRECT_PAIR (AV_CH_SURROUND_DIRECT_LEFT | AV_CH_SURROUND_DIRECT_RIGHT)
 546 #define CH_BACK_PAIR   (AV_CH_BACK_LEFT            | AV_CH_BACK_RIGHT)
 547
 548 /* allowable substitutions for channel pairs when comparing layouts,
 549  * ordered by priority for both values */
 550 static const uint64_t ch_subst[][2] = {
 551     { CH_FRONT_PAIR,      CH_CENTER_PAIR     },
 552     { CH_FRONT_PAIR,      CH_WIDE_PAIR       },
 553     { CH_FRONT_PAIR,      AV_CH_FRONT_CENTER },
 554     { CH_CENTER_PAIR,     CH_FRONT_PAIR      },
 555     { CH_CENTER_PAIR,     CH_WIDE_PAIR       },
 556     { CH_CENTER_PAIR,     AV_CH_FRONT_CENTER },
 557     { CH_WIDE_PAIR,       CH_FRONT_PAIR      },
 558     { CH_WIDE_PAIR,       CH_CENTER_PAIR     },
 559     { CH_WIDE_PAIR,       AV_CH_FRONT_CENTER },
 560     { AV_CH_FRONT_CENTER, CH_FRONT_PAIR      },
 561     { AV_CH_FRONT_CENTER, CH_CENTER_PAIR     },
 562     { AV_CH_FRONT_CENTER, CH_WIDE_PAIR       },
 563     { CH_SIDE_PAIR,       CH_DIRECT_PAIR     },
 564     { CH_SIDE_PAIR,       CH_BACK_PAIR       },
 565     { CH_SIDE_PAIR,       AV_CH_BACK_CENTER  },
 566     { CH_BACK_PAIR,       CH_DIRECT_PAIR     },
 567     { CH_BACK_PAIR,       CH_SIDE_PAIR       },
 568     { CH_BACK_PAIR,       AV_CH_BACK_CENTER  },
 569     { AV_CH_BACK_CENTER,  CH_BACK_PAIR       },
 570     { AV_CH_BACK_CENTER,  CH_DIRECT_PAIR     },
 571     { AV_CH_BACK_CENTER,  CH_SIDE_PAIR       },
 572 };
 573
 574 static void swap_channel_layouts_on_filter(AVFilterContext *filter)
 575 {
 576     AVFilterLink *link = NULL;
 577     int i, j, k;
 578
 579     for (i = 0; i < filter->nb_inputs; i++) {
 580         link = filter->inputs[i];
 581
 582         if (link->type == AVMEDIA_TYPE_AUDIO &&
 583             link->out_channel_layouts->nb_channel_layouts == 1)
 584             break;
 585     }
 586     if (i == filter->nb_inputs)
 587         return;
 588
 589     for (i = 0; i < filter->nb_outputs; i++) {
 590         AVFilterLink *outlink = filter->outputs[i];
 591         int best_idx = -1, best_score = INT_MIN, best_count_diff = INT_MAX;
 592
 593         if (outlink->type != AVMEDIA_TYPE_AUDIO ||
 594             outlink->in_channel_layouts->nb_channel_layouts < 2)
 595             continue;
 596
 597         for (j = 0; j < outlink->in_channel_layouts->nb_channel_layouts; j++) {
 598             uint64_t  in_chlayout = link->out_channel_layouts->channel_layouts[0];
 599             uint64_t out_chlayout = outlink->in_channel_layouts->channel_layouts[j];
 600             int  in_channels      = av_get_channel_layout_nb_channels(in_chlayout);
 601             int out_channels      = av_get_channel_layout_nb_channels(out_chlayout);
 602             int count_diff        = out_channels - in_channels;
 603             int matched_channels, extra_channels;
 604             int score = 0;
 605
 606             /* channel substitution */
 607             for (k = 0; k < FF_ARRAY_ELEMS(ch_subst); k++) {
 608                 uint64_t cmp0 = ch_subst[k][0];
 609                 uint64_t cmp1 = ch_subst[k][1];
 610                 if (( in_chlayout & cmp0) && (!(out_chlayout & cmp0)) &&
 611                     (out_chlayout & cmp1) && (!( in_chlayout & cmp1))) {
 612                     in_chlayout  &= ~cmp0;
 613                     out_chlayout &= ~cmp1;
 614                     /* add score for channel match, minus a deduction for
 615                        having to do the substitution */
 616                     score += 10 * av_get_channel_layout_nb_channels(cmp1) - 2;
 617                 }
 618             }
 619
 620             /* no penalty for LFE channel mismatch */
 621             if ( (in_chlayout & AV_CH_LOW_FREQUENCY) &&
 622                 (out_chlayout & AV_CH_LOW_FREQUENCY))
 623                 score += 10;
 624             in_chlayout  &= ~AV_CH_LOW_FREQUENCY;
 625             out_chlayout &= ~AV_CH_LOW_FREQUENCY;
 626
 627             matched_channels = av_get_channel_layout_nb_channels(in_chlayout &
 628                                                                  out_chlayout);
 629             extra_channels   = av_get_channel_layout_nb_channels(out_chlayout &
 630                                                                  (~in_chlayout));
 631             score += 10 * matched_channels - 5 * extra_channels;
 632
 633             if (score > best_score ||
 634                 (count_diff < best_count_diff && score == best_score)) {
 635                 best_score = score;
 636                 best_idx   = j;
 637                 best_count_diff = count_diff;
 638             }
 639         }
 640         av_assert0(best_idx >= 0);
 641         FFSWAP(uint64_t, outlink->in_channel_layouts->channel_layouts[0],
 642                outlink->in_channel_layouts->channel_layouts[best_idx]);
 643     }
 644
 645 }
 646
 647 static void swap_channel_layouts(AVFilterGraph *graph)
 648 {
 649     int i;
 650
 651     for (i = 0; i < graph->nb_filters; i++)
 652         swap_channel_layouts_on_filter(graph->filters[i]);
 653 }
 654
 655 static void swap_sample_fmts_on_filter(AVFilterContext *filter)
 656 {
 657     AVFilterLink *link = NULL;
 658     int format, bps;
 659     int i, j;
 660
 661     for (i = 0; i < filter->nb_inputs; i++) {
 662         link = filter->inputs[i];
 663
 664         if (link->type == AVMEDIA_TYPE_AUDIO &&
 665             link->out_formats->nb_formats == 1)
 666             break;
 667     }
 668     if (i == filter->nb_inputs)
 669         return;
 670
 671     format = link->out_formats->formats[0];
 672     bps    = av_get_bytes_per_sample(format);
 673
 674     for (i = 0; i < filter->nb_outputs; i++) {
 675         AVFilterLink *outlink = filter->outputs[i];
 676         int best_idx = -1, best_score = INT_MIN;
 677
 678         if (outlink->type != AVMEDIA_TYPE_AUDIO ||
 679             outlink->in_formats->nb_formats < 2)
 680             continue;
 681
 682         for (j = 0; j < outlink->in_formats->nb_formats; j++) {
 683             int out_format = outlink->in_formats->formats[j];
 684             int out_bps    = av_get_bytes_per_sample(out_format);
 685             int score;
 686
 687             if (av_get_packed_sample_fmt(out_format) == format ||
 688                 av_get_planar_sample_fmt(out_format) == format) {
 689                 best_idx   = j;
 690                 break;
 691             }
 692
 693             /* for s32 and float prefer double to prevent loss of information */
 694             if (bps == 4 && out_bps == 8) {
 695                 best_idx = j;
 696                 break;
 697             }
 698
 699             /* prefer closest higher or equal bps */
 700             score = -abs(out_bps - bps);
 701             if (out_bps >= bps)
 702                 score += INT_MAX/2;
 703
 704             if (score > best_score) {
 705                 best_score = score;
 706                 best_idx   = j;
 707             }
 708         }
 709         av_assert0(best_idx >= 0);
 710         FFSWAP(int, outlink->in_formats->formats[0],
 711                outlink->in_formats->formats[best_idx]);
 712     }
 713 }
 714
 715 static void swap_sample_fmts(AVFilterGraph *graph)
 716 {
 717     int i;
 718
 719     for (i = 0; i < graph->nb_filters; i++)
 720         swap_sample_fmts_on_filter(graph->filters[i]);
 721
 722 }
 723
 724 static int pick_formats(AVFilterGraph *graph)
 725 {
 726     int i, j, ret;
 727
 728     for (i = 0; i < graph->nb_filters; i++) {
 729         AVFilterContext *filter = graph->filters[i];
 730
 731         for (j = 0; j < filter->nb_inputs; j++)
 732             if ((ret = pick_format(filter->inputs[j])) < 0)
 733                 return ret;
 734         for (j = 0; j < filter->nb_outputs; j++)
 735             if ((ret = pick_format(filter->outputs[j])) < 0)
 736                 return ret;
 737     }
 738     return 0;
 739 }
 740
 741 /**
 742  * Configure the formats of all the links in the graph.
 743  */
 744 static int graph_config_formats(AVFilterGraph *graph, AVClass *log_ctx)
 745 {
 746     int ret;
 747
 748     /* find supported formats from sub-filters, and merge along links */
 749     if ((ret = query_formats(graph, log_ctx)) < 0)
 750         return ret;
 751
 752     /* Once everything is merged, it's possible that we'll still have
 753      * multiple valid media format choices. We try to minimize the amount
 754      * of format conversion inside filters */
 755     reduce_formats(graph);
 756
 757     /* for audio filters, ensure the best format, sample rate and channel layout
 758      * is selected */
 759     swap_sample_fmts(graph);
 760     swap_samplerates(graph);
 761     swap_channel_layouts(graph);
 762
 763     if ((ret = pick_formats(graph)) < 0)
 764         return ret;
 765
 766     return 0;
 767 }
 768
 769 static int graph_insert_fifos(AVFilterGraph *graph, AVClass *log_ctx)
 770 {
 771     AVFilterContext *f;
 772     int i, j, ret;
 773     int fifo_count = 0;
 774
 775     for (i = 0; i < graph->nb_filters; i++) {
 776         f = graph->filters[i];
 777
 778         for (j = 0; j < f->nb_inputs; j++) {
 779             AVFilterLink *link = f->inputs[j];
 780             AVFilterContext *fifo_ctx;
 781             AVFilter *fifo;
 782             char name[32];
 783
 784             if (!link->dstpad->needs_fifo)
 785                 continue;
 786
 787             fifo = f->inputs[j]->type == AVMEDIA_TYPE_VIDEO ?
 788                    avfilter_get_by_name("fifo") :
 789                    avfilter_get_by_name("afifo");
 790
 791             snprintf(name, sizeof(name), "auto-inserted fifo %d", fifo_count++);
 792
 793             ret = avfilter_graph_create_filter(&fifo_ctx, fifo, name, NULL,
 794                                                NULL, graph);
 795             if (ret < 0)
 796                 return ret;
 797
 798             ret = avfilter_insert_filter(link, fifo_ctx, 0, 0);
 799             if (ret < 0)
 800                 return ret;
 801         }
 802     }
 803
 804     return 0;
 805 }
 806
 807 int avfilter_graph_config(AVFilterGraph *graphctx, void *log_ctx)
 808 {
 809     int ret;
 810
 811     if ((ret = graph_check_validity(graphctx, log_ctx)))
 812         return ret;
 813     if ((ret = graph_insert_fifos(graphctx, log_ctx)) < 0)
 814         return ret;
 815     if ((ret = graph_config_formats(graphctx, log_ctx)))
 816         return ret;
 817     if ((ret = graph_config_links(graphctx, log_ctx)))
 818         return ret;
 819
 820     return 0;
 821 }