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