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

   1 /*
   2  * Filter layer - format negotiation
   3  * Copyright (c) 2007 Bobby Bingham
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/avassert.h"
  23 #include "libavutil/channel_layout.h"
  24 #include "libavutil/common.h"
  25 #include "libavutil/eval.h"
  26 #include "libavutil/pixdesc.h"
  27 #include "libavutil/parseutils.h"
  28 #include "avfilter.h"
  29 #include "internal.h"
  30 #include "formats.h"
  31
  32 #define KNOWN(l) (!FF_LAYOUT2COUNT(l)) /* for readability */
  33
  34 /**
  35  * Add all refs from a to ret and destroy a.
  36  */
  37 #define MERGE_REF(ret, a, fmts, type, fail)                                \
  38 do {                                                                       \
  39     type ***tmp;                                                           \
  40     int i;                                                                 \
  41                                                                            \
  42     if (!(tmp = av_realloc_array(ret->refs, ret->refcount + a->refcount,   \
  43                                  sizeof(*tmp))))                           \
  44         goto fail;                                                         \
  45     ret->refs = tmp;                                                       \
  46                                                                            \
  47     for (i = 0; i < a->refcount; i ++) {                                   \
  48         ret->refs[ret->refcount] = a->refs[i];                             \
  49         *ret->refs[ret->refcount++] = ret;                                 \
  50     }                                                                      \
  51                                                                            \
  52     av_freep(&a->refs);                                                    \
  53     av_freep(&a->fmts);                                                    \
  54     av_freep(&a);                                                          \
  55 } while (0)
  56
  57 /**
  58  * Add all formats common for a and b to ret, copy the refs and destroy
  59  * a and b.
  60  */
  61 #define MERGE_FORMATS(ret, a, b, fmts, nb, type, fail)                          \
  62 do {                                                                            \
  63     int i, j, k = 0, count = FFMIN(a->nb, b->nb);                               \
  64                                                                                 \
  65     if (!(ret = av_mallocz(sizeof(*ret))))                                      \
  66         goto fail;                                                              \
  67                                                                                 \
  68     if (count) {                                                                \
  69         if (!(ret->fmts = av_malloc_array(count, sizeof(*ret->fmts))))          \
  70             goto fail;                                                          \
  71         for (i = 0; i < a->nb; i++)                                             \
  72             for (j = 0; j < b->nb; j++)                                         \
  73                 if (a->fmts[i] == b->fmts[j]) {                                 \
  74                     if(k >= FFMIN(a->nb, b->nb)){                               \
  75                         av_log(NULL, AV_LOG_ERROR, "Duplicate formats in avfilter_merge_formats() detected\n"); \
  76                         av_free(ret->fmts);                                     \
  77                         av_free(ret);                                           \
  78                         return NULL;                                            \
  79                     }                                                           \
  80                     ret->fmts[k++] = a->fmts[i];                                \
  81                 }                                                               \
  82     }                                                                           \
  83     ret->nb = k;                                                                \
  84     /* check that there was at least one common format */                       \
  85     if (!ret->nb)                                                               \
  86         goto fail;                                                              \
  87                                                                                 \
  88     MERGE_REF(ret, a, fmts, type, fail);                                        \
  89     MERGE_REF(ret, b, fmts, type, fail);                                        \
  90 } while (0)
  91
  92 AVFilterFormats *ff_merge_formats(AVFilterFormats *a, AVFilterFormats *b,
  93                                   enum AVMediaType type)
  94 {
  95     AVFilterFormats *ret = NULL;
  96     int i, j;
  97     int alpha1=0, alpha2=0;
  98     int chroma1=0, chroma2=0;
  99
 100     if (a == b)
 101         return a;
 102
 103     /* Do not lose chroma or alpha in merging.
 104        It happens if both lists have formats with chroma (resp. alpha), but
 105        the only formats in common do not have it (e.g. YUV+gray vs.
 106        RGB+gray): in that case, the merging would select the gray format,
 107        possibly causing a lossy conversion elsewhere in the graph.
 108        To avoid that, pretend that there are no common formats to force the
 109        insertion of a conversion filter. */
 110     if (type == AVMEDIA_TYPE_VIDEO)
 111         for (i = 0; i < a->nb_formats; i++)
 112             for (j = 0; j < b->nb_formats; j++) {
 113                 const AVPixFmtDescriptor *adesc = av_pix_fmt_desc_get(a->formats[i]);
 114                 const AVPixFmtDescriptor *bdesc = av_pix_fmt_desc_get(b->formats[j]);
 115                 alpha2 |= adesc->flags & bdesc->flags & AV_PIX_FMT_FLAG_ALPHA;
 116                 chroma2|= adesc->nb_components > 1 && bdesc->nb_components > 1;
 117                 if (a->formats[i] == b->formats[j]) {
 118                     alpha1 |= adesc->flags & AV_PIX_FMT_FLAG_ALPHA;
 119                     chroma1|= adesc->nb_components > 1;
 120                 }
 121             }
 122
 123     // If chroma or alpha can be lost through merging then do not merge
 124     if (alpha2 > alpha1 || chroma2 > chroma1)
 125         return NULL;
 126
 127     MERGE_FORMATS(ret, a, b, formats, nb_formats, AVFilterFormats, fail);
 128
 129     return ret;
 130 fail:
 131     if (ret) {
 132         av_freep(&ret->refs);
 133         av_freep(&ret->formats);
 134     }
 135     av_freep(&ret);
 136     return NULL;
 137 }
 138
 139 AVFilterFormats *ff_merge_samplerates(AVFilterFormats *a,
 140                                       AVFilterFormats *b)
 141 {
 142     AVFilterFormats *ret = NULL;
 143
 144     if (a == b) return a;
 145
 146     if (a->nb_formats && b->nb_formats) {
 147         MERGE_FORMATS(ret, a, b, formats, nb_formats, AVFilterFormats, fail);
 148     } else if (a->nb_formats) {
 149         MERGE_REF(a, b, formats, AVFilterFormats, fail);
 150         ret = a;
 151     } else {
 152         MERGE_REF(b, a, formats, AVFilterFormats, fail);
 153         ret = b;
 154     }
 155
 156     return ret;
 157 fail:
 158     if (ret) {
 159         av_freep(&ret->refs);
 160         av_freep(&ret->formats);
 161     }
 162     av_freep(&ret);
 163     return NULL;
 164 }
 165
 166 AVFilterChannelLayouts *ff_merge_channel_layouts(AVFilterChannelLayouts *a,
 167                                                  AVFilterChannelLayouts *b)
 168 {
 169     AVFilterChannelLayouts *ret = NULL;
 170     unsigned a_all = a->all_layouts + a->all_counts;
 171     unsigned b_all = b->all_layouts + b->all_counts;
 172     int ret_max, ret_nb = 0, i, j, round;
 173
 174     if (a == b) return a;
 175
 176     /* Put the most generic set in a, to avoid doing everything twice */
 177     if (a_all < b_all) {
 178         FFSWAP(AVFilterChannelLayouts *, a, b);
 179         FFSWAP(unsigned, a_all, b_all);
 180     }
 181     if (a_all) {
 182         if (a_all == 1 && !b_all) {
 183             /* keep only known layouts in b; works also for b_all = 1 */
 184             for (i = j = 0; i < b->nb_channel_layouts; i++)
 185                 if (KNOWN(b->channel_layouts[i]))
 186                     b->channel_layouts[j++] = b->channel_layouts[i];
 187             /* Not optimal: the unknown layouts of b may become known after
 188                another merge. */
 189             if (!j)
 190                 return NULL;
 191             b->nb_channel_layouts = j;
 192         }
 193         MERGE_REF(b, a, channel_layouts, AVFilterChannelLayouts, fail);
 194         return b;
 195     }
 196
 197     ret_max = a->nb_channel_layouts + b->nb_channel_layouts;
 198     if (!(ret = av_mallocz(sizeof(*ret))) ||
 199         !(ret->channel_layouts = av_malloc_array(ret_max,
 200                                                  sizeof(*ret->channel_layouts))))
 201         goto fail;
 202
 203     /* a[known] intersect b[known] */
 204     for (i = 0; i < a->nb_channel_layouts; i++) {
 205         if (!KNOWN(a->channel_layouts[i]))
 206             continue;
 207         for (j = 0; j < b->nb_channel_layouts; j++) {
 208             if (a->channel_layouts[i] == b->channel_layouts[j]) {
 209                 ret->channel_layouts[ret_nb++] = a->channel_layouts[i];
 210                 a->channel_layouts[i] = b->channel_layouts[j] = 0;
 211             }
 212         }
 213     }
 214     /* 1st round: a[known] intersect b[generic]
 215        2nd round: a[generic] intersect b[known] */
 216     for (round = 0; round < 2; round++) {
 217         for (i = 0; i < a->nb_channel_layouts; i++) {
 218             uint64_t fmt = a->channel_layouts[i], bfmt;
 219             if (!fmt || !KNOWN(fmt))
 220                 continue;
 221             bfmt = FF_COUNT2LAYOUT(av_get_channel_layout_nb_channels(fmt));
 222             for (j = 0; j < b->nb_channel_layouts; j++)
 223                 if (b->channel_layouts[j] == bfmt)
 224                     ret->channel_layouts[ret_nb++] = a->channel_layouts[i];
 225         }
 226         /* 1st round: swap to prepare 2nd round; 2nd round: put it back */
 227         FFSWAP(AVFilterChannelLayouts *, a, b);
 228     }
 229     /* a[generic] intersect b[generic] */
 230     for (i = 0; i < a->nb_channel_layouts; i++) {
 231         if (KNOWN(a->channel_layouts[i]))
 232             continue;
 233         for (j = 0; j < b->nb_channel_layouts; j++)
 234             if (a->channel_layouts[i] == b->channel_layouts[j])
 235                 ret->channel_layouts[ret_nb++] = a->channel_layouts[i];
 236     }
 237
 238     ret->nb_channel_layouts = ret_nb;
 239     if (!ret->nb_channel_layouts)
 240         goto fail;
 241     MERGE_REF(ret, a, channel_layouts, AVFilterChannelLayouts, fail);
 242     MERGE_REF(ret, b, channel_layouts, AVFilterChannelLayouts, fail);
 243     return ret;
 244
 245 fail:
 246     if (ret) {
 247         av_freep(&ret->refs);
 248         av_freep(&ret->channel_layouts);
 249     }
 250     av_freep(&ret);
 251     return NULL;
 252 }
 253
 254 int ff_fmt_is_in(int fmt, const int *fmts)
 255 {
 256     const int *p;
 257
 258     for (p = fmts; *p != -1; p++) {
 259         if (fmt == *p)
 260             return 1;
 261     }
 262     return 0;
 263 }
 264
 265 #define COPY_INT_LIST(list_copy, list, type) {                          \
 266     int count = 0;                                                      \
 267     if (list)                                                           \
 268         for (count = 0; list[count] != -1; count++)                     \
 269             ;                                                           \
 270     list_copy = av_calloc(count+1, sizeof(type));                       \
 271     if (list_copy) {                                                    \
 272         memcpy(list_copy, list, sizeof(type) * count);                  \
 273         list_copy[count] = -1;                                          \
 274     }                                                                   \
 275 }
 276
 277 #define MAKE_FORMAT_LIST(type, field, count_field)                      \
 278     type *formats;                                                      \
 279     int count = 0;                                                      \
 280     if (fmts)                                                           \
 281         for (count = 0; fmts[count] != -1; count++)                     \
 282             ;                                                           \
 283     formats = av_mallocz(sizeof(*formats));                             \
 284     if (!formats) return NULL;                                          \
 285     formats->count_field = count;                                       \
 286     if (count) {                                                        \
 287         formats->field = av_malloc_array(count, sizeof(*formats->field));      \
 288         if (!formats->field) {                                          \
 289             av_free(formats);                                           \
 290             return NULL;                                                \
 291         }                                                               \
 292     }
 293
 294 AVFilterFormats *ff_make_format_list(const int *fmts)
 295 {
 296     MAKE_FORMAT_LIST(AVFilterFormats, formats, nb_formats);
 297     while (count--)
 298         formats->formats[count] = fmts[count];
 299
 300     return formats;
 301 }
 302
 303 AVFilterChannelLayouts *avfilter_make_format64_list(const int64_t *fmts)
 304 {
 305     MAKE_FORMAT_LIST(AVFilterChannelLayouts,
 306                      channel_layouts, nb_channel_layouts);
 307     if (count)
 308         memcpy(formats->channel_layouts, fmts,
 309                sizeof(*formats->channel_layouts) * count);
 310
 311     return formats;
 312 }
 313
 314 #define ADD_FORMAT(f, fmt, type, list, nb)                  \
 315 do {                                                        \
 316     type *fmts;                                             \
 317                                                             \
 318     if (!(*f) && !(*f = av_mallocz(sizeof(**f))))           \
 319         return AVERROR(ENOMEM);                             \
 320                                                             \
 321     fmts = av_realloc((*f)->list,                           \
 322                       sizeof(*(*f)->list) * ((*f)->nb + 1));\
 323     if (!fmts)                                              \
 324         return AVERROR(ENOMEM);                             \
 325                                                             \
 326     (*f)->list = fmts;                                      \
 327     (*f)->list[(*f)->nb++] = fmt;                           \
 328 } while (0)
 329
 330 int ff_add_format(AVFilterFormats **avff, int64_t fmt)
 331 {
 332     ADD_FORMAT(avff, fmt, int, formats, nb_formats);
 333     return 0;
 334 }
 335
 336 int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout)
 337 {
 338     av_assert1(!(*l && (*l)->all_layouts));
 339     ADD_FORMAT(l, channel_layout, uint64_t, channel_layouts, nb_channel_layouts);
 340     return 0;
 341 }
 342
 343 AVFilterFormats *ff_all_formats(enum AVMediaType type)
 344 {
 345     AVFilterFormats *ret = NULL;
 346
 347     if (type == AVMEDIA_TYPE_VIDEO) {
 348         const AVPixFmtDescriptor *desc = NULL;
 349         while ((desc = av_pix_fmt_desc_next(desc))) {
 350             if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL))
 351                 ff_add_format(&ret, av_pix_fmt_desc_get_id(desc));
 352         }
 353     } else if (type == AVMEDIA_TYPE_AUDIO) {
 354         enum AVSampleFormat fmt = 0;
 355         while (av_get_sample_fmt_name(fmt)) {
 356             ff_add_format(&ret, fmt);
 357             fmt++;
 358         }
 359     }
 360
 361     return ret;
 362 }
 363
 364 const int64_t avfilter_all_channel_layouts[] = {
 365 #include "all_channel_layouts.inc"
 366     -1
 367 };
 368
 369 // AVFilterFormats *avfilter_make_all_channel_layouts(void)
 370 // {
 371 //     return avfilter_make_format64_list(avfilter_all_channel_layouts);
 372 // }
 373
 374 AVFilterFormats *ff_planar_sample_fmts(void)
 375 {
 376     AVFilterFormats *ret = NULL;
 377     int fmt;
 378
 379     for (fmt = 0; av_get_bytes_per_sample(fmt)>0; fmt++)
 380         if (av_sample_fmt_is_planar(fmt))
 381             ff_add_format(&ret, fmt);
 382
 383     return ret;
 384 }
 385
 386 AVFilterFormats *ff_all_samplerates(void)
 387 {
 388     AVFilterFormats *ret = av_mallocz(sizeof(*ret));
 389     return ret;
 390 }
 391
 392 AVFilterChannelLayouts *ff_all_channel_layouts(void)
 393 {
 394     AVFilterChannelLayouts *ret = av_mallocz(sizeof(*ret));
 395     if (!ret)
 396         return NULL;
 397     ret->all_layouts = 1;
 398     return ret;
 399 }
 400
 401 AVFilterChannelLayouts *ff_all_channel_counts(void)
 402 {
 403     AVFilterChannelLayouts *ret = av_mallocz(sizeof(*ret));
 404     if (!ret)
 405         return NULL;
 406     ret->all_layouts = ret->all_counts = 1;
 407     return ret;
 408 }
 409
 410 #define FORMATS_REF(f, ref)                                          \
 411 do {                                                                 \
 412     *ref = f;                                                        \
 413     f->refs = av_realloc(f->refs, sizeof(*f->refs) * ++f->refcount); \
 414     f->refs[f->refcount-1] = ref;                                    \
 415 } while (0)
 416
 417 void ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
 418 {
 419     FORMATS_REF(f, ref);
 420 }
 421
 422 void ff_formats_ref(AVFilterFormats *f, AVFilterFormats **ref)
 423 {
 424     FORMATS_REF(f, ref);
 425 }
 426
 427 #define FIND_REF_INDEX(ref, idx)            \
 428 do {                                        \
 429     int i;                                  \
 430     for (i = 0; i < (*ref)->refcount; i ++) \
 431         if((*ref)->refs[i] == ref) {        \
 432             idx = i;                        \
 433             break;                          \
 434         }                                   \
 435 } while (0)
 436
 437 #define FORMATS_UNREF(ref, list)                                   \
 438 do {                                                               \
 439     int idx = -1;                                                  \
 440                                                                    \
 441     if (!*ref)                                                     \
 442         return;                                                    \
 443                                                                    \
 444     FIND_REF_INDEX(ref, idx);                                      \
 445                                                                    \
 446     if (idx >= 0)                                                  \
 447         memmove((*ref)->refs + idx, (*ref)->refs + idx + 1,        \
 448             sizeof(*(*ref)->refs) * ((*ref)->refcount - idx - 1)); \
 449                                                                    \
 450     if(!--(*ref)->refcount) {                                      \
 451         av_free((*ref)->list);                                     \
 452         av_free((*ref)->refs);                                     \
 453         av_free(*ref);                                             \
 454     }                                                              \
 455     *ref = NULL;                                                   \
 456 } while (0)
 457
 458 void ff_formats_unref(AVFilterFormats **ref)
 459 {
 460     FORMATS_UNREF(ref, formats);
 461 }
 462
 463 void ff_channel_layouts_unref(AVFilterChannelLayouts **ref)
 464 {
 465     FORMATS_UNREF(ref, channel_layouts);
 466 }
 467
 468 #define FORMATS_CHANGEREF(oldref, newref)       \
 469 do {                                            \
 470     int idx = -1;                               \
 471                                                 \
 472     FIND_REF_INDEX(oldref, idx);                \
 473                                                 \
 474     if (idx >= 0) {                             \
 475         (*oldref)->refs[idx] = newref;          \
 476         *newref = *oldref;                      \
 477         *oldref = NULL;                         \
 478     }                                           \
 479 } while (0)
 480
 481 void ff_channel_layouts_changeref(AVFilterChannelLayouts **oldref,
 482                                   AVFilterChannelLayouts **newref)
 483 {
 484     FORMATS_CHANGEREF(oldref, newref);
 485 }
 486
 487 void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref)
 488 {
 489     FORMATS_CHANGEREF(oldref, newref);
 490 }
 491
 492 #define SET_COMMON_FORMATS(ctx, fmts, in_fmts, out_fmts, ref, list) \
 493 {                                                                   \
 494     int count = 0, i;                                               \
 495                                                                     \
 496     for (i = 0; i < ctx->nb_inputs; i++) {                          \
 497         if (ctx->inputs[i] && !ctx->inputs[i]->out_fmts) {          \
 498             ref(fmts, &ctx->inputs[i]->out_fmts);                   \
 499             count++;                                                \
 500         }                                                           \
 501     }                                                               \
 502     for (i = 0; i < ctx->nb_outputs; i++) {                         \
 503         if (ctx->outputs[i] && !ctx->outputs[i]->in_fmts) {         \
 504             ref(fmts, &ctx->outputs[i]->in_fmts);                   \
 505             count++;                                                \
 506         }                                                           \
 507     }                                                               \
 508                                                                     \
 509     if (!count) {                                                   \
 510         av_freep(&fmts->list);                                      \
 511         av_freep(&fmts->refs);                                      \
 512         av_freep(&fmts);                                            \
 513     }                                                               \
 514 }
 515
 516 void ff_set_common_channel_layouts(AVFilterContext *ctx,
 517                                    AVFilterChannelLayouts *layouts)
 518 {
 519     SET_COMMON_FORMATS(ctx, layouts, in_channel_layouts, out_channel_layouts,
 520                        ff_channel_layouts_ref, channel_layouts);
 521 }
 522
 523 void ff_set_common_samplerates(AVFilterContext *ctx,
 524                                AVFilterFormats *samplerates)
 525 {
 526     SET_COMMON_FORMATS(ctx, samplerates, in_samplerates, out_samplerates,
 527                        ff_formats_ref, formats);
 528 }
 529
 530 /**
 531  * A helper for query_formats() which sets all links to the same list of
 532  * formats. If there are no links hooked to this filter, the list of formats is
 533  * freed.
 534  */
 535 void ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
 536 {
 537     SET_COMMON_FORMATS(ctx, formats, in_formats, out_formats,
 538                        ff_formats_ref, formats);
 539 }
 540
 541 static int default_query_formats_common(AVFilterContext *ctx,
 542                                         AVFilterChannelLayouts *(layouts)(void))
 543 {
 544     enum AVMediaType type = ctx->inputs  && ctx->inputs [0] ? ctx->inputs [0]->type :
 545                             ctx->outputs && ctx->outputs[0] ? ctx->outputs[0]->type :
 546                             AVMEDIA_TYPE_VIDEO;
 547
 548     ff_set_common_formats(ctx, ff_all_formats(type));
 549     if (type == AVMEDIA_TYPE_AUDIO) {
 550         ff_set_common_channel_layouts(ctx, layouts());
 551         ff_set_common_samplerates(ctx, ff_all_samplerates());
 552     }
 553
 554     return 0;
 555 }
 556
 557 int ff_default_query_formats(AVFilterContext *ctx)
 558 {
 559     return default_query_formats_common(ctx, ff_all_channel_layouts);
 560 }
 561
 562 int ff_query_formats_all(AVFilterContext *ctx)
 563 {
 564     return default_query_formats_common(ctx, ff_all_channel_counts);
 565 }
 566
 567 /* internal functions for parsing audio format arguments */
 568
 569 int ff_parse_pixel_format(enum AVPixelFormat *ret, const char *arg, void *log_ctx)
 570 {
 571     char *tail;
 572     int pix_fmt = av_get_pix_fmt(arg);
 573     if (pix_fmt == AV_PIX_FMT_NONE) {
 574         pix_fmt = strtol(arg, &tail, 0);
 575         if (*tail || !av_pix_fmt_desc_get(pix_fmt)) {
 576             av_log(log_ctx, AV_LOG_ERROR, "Invalid pixel format '%s'\n", arg);
 577             return AVERROR(EINVAL);
 578         }
 579     }
 580     *ret = pix_fmt;
 581     return 0;
 582 }
 583
 584 int ff_parse_sample_format(int *ret, const char *arg, void *log_ctx)
 585 {
 586     char *tail;
 587     int sfmt = av_get_sample_fmt(arg);
 588     if (sfmt == AV_SAMPLE_FMT_NONE) {
 589         sfmt = strtol(arg, &tail, 0);
 590         if (*tail || av_get_bytes_per_sample(sfmt)<=0) {
 591             av_log(log_ctx, AV_LOG_ERROR, "Invalid sample format '%s'\n", arg);
 592             return AVERROR(EINVAL);
 593         }
 594     }
 595     *ret = sfmt;
 596     return 0;
 597 }
 598
 599 int ff_parse_time_base(AVRational *ret, const char *arg, void *log_ctx)
 600 {
 601     AVRational r;
 602     if(av_parse_ratio(&r, arg, INT_MAX, 0, log_ctx) < 0 ||r.num<=0  ||r.den<=0) {
 603         av_log(log_ctx, AV_LOG_ERROR, "Invalid time base '%s'\n", arg);
 604         return AVERROR(EINVAL);
 605     }
 606     *ret = r;
 607     return 0;
 608 }
 609
 610 int ff_parse_sample_rate(int *ret, const char *arg, void *log_ctx)
 611 {
 612     char *tail;
 613     double srate = av_strtod(arg, &tail);
 614     if (*tail || srate < 1 || (int)srate != srate || srate > INT_MAX) {
 615         av_log(log_ctx, AV_LOG_ERROR, "Invalid sample rate '%s'\n", arg);
 616         return AVERROR(EINVAL);
 617     }
 618     *ret = srate;
 619     return 0;
 620 }
 621
 622 int ff_parse_channel_layout(int64_t *ret, int *nret, const char *arg,
 623                             void *log_ctx)
 624 {
 625     char *tail;
 626     int64_t chlayout, count;
 627
 628     if (nret) {
 629         count = strtol(arg, &tail, 10);
 630         if (*tail == 'c' && !tail[1] && count > 0 && count < 63) {
 631             *nret = count;
 632             *ret = 0;
 633             return 0;
 634         }
 635     }
 636     chlayout = av_get_channel_layout(arg);
 637     if (chlayout == 0) {
 638         chlayout = strtol(arg, &tail, 10);
 639         if (*tail || chlayout == 0) {
 640             av_log(log_ctx, AV_LOG_ERROR, "Invalid channel layout '%s'\n", arg);
 641             return AVERROR(EINVAL);
 642         }
 643     }
 644     *ret = chlayout;
 645     if (nret)
 646         *nret = av_get_channel_layout_nb_channels(chlayout);
 647     return 0;
 648 }
 649
 650 #ifdef TEST
 651
 652 #undef printf
 653
 654 int main(void)
 655 {
 656     const int64_t *cl;
 657     char buf[512];
 658
 659     for (cl = avfilter_all_channel_layouts; *cl != -1; cl++) {
 660         av_get_channel_layout_string(buf, sizeof(buf), -1, *cl);
 661         printf("%s\n", buf);
 662     }
 663
 664     return 0;
 665 }
 666
 667 #endif
 668