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