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