aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/avformat.c
blob: 708d90b38ccef27f0683bf0993febb5b3c5c8113 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
/*
 * Various functions used by both muxers and demuxers
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <math.h>
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "libavutil/opt.h"
#include "libavutil/pixfmt.h"
#include "libavutil/samplefmt.h"
#include "libavcodec/avcodec.h"
#include "libavcodec/bsf.h"
#include "libavcodec/codec_desc.h"
#include "libavcodec/packet_internal.h"
#include "avformat.h"
#include "avio.h"
#include "demux.h"
#include "mux.h"
#include "internal.h"

void ff_free_stream(AVStream **pst)
{
    AVStream *st = *pst;
    FFStream *const sti = ffstream(st);

    if (!st)
        return;

    for (int i = 0; i < st->nb_side_data; i++)
        av_freep(&st->side_data[i].data);
    av_freep(&st->side_data);

    if (st->attached_pic.data)
        av_packet_unref(&st->attached_pic);

    av_parser_close(sti->parser);
    avcodec_free_context(&sti->avctx);
    av_bsf_free(&sti->bsfc);
    av_freep(&sti->priv_pts);
    av_freep(&sti->index_entries);
    av_freep(&sti->probe_data.buf);

    av_bsf_free(&sti->extract_extradata.bsf);

    if (sti->info) {
        av_freep(&sti->info->duration_error);
        av_freep(&sti->info);
    }

    av_dict_free(&st->metadata);
    avcodec_parameters_free(&st->codecpar);
    av_freep(&st->priv_data);

    av_freep(pst);
}

void ff_remove_stream(AVFormatContext *s, AVStream *st)
{
    av_assert0(s->nb_streams>0);
    av_assert0(s->streams[ s->nb_streams - 1 ] == st);

    ff_free_stream(&s->streams[ --s->nb_streams ]);
}

/* XXX: suppress the packet queue */
void ff_flush_packet_queue(AVFormatContext *s)
{
    FFFormatContext *const si = ffformatcontext(s);
    avpriv_packet_list_free(&si->parse_queue);
    avpriv_packet_list_free(&si->packet_buffer);
    avpriv_packet_list_free(&si->raw_packet_buffer);

    si->raw_packet_buffer_size = 0;
}

void avformat_free_context(AVFormatContext *s)
{
    FFFormatContext *si;

    if (!s)
        return;
    si = ffformatcontext(s);

    if (s->oformat && ffofmt(s->oformat)->deinit && si->initialized)
        ffofmt(s->oformat)->deinit(s);

    av_opt_free(s);
    if (s->iformat && s->iformat->priv_class && s->priv_data)
        av_opt_free(s->priv_data);
    if (s->oformat && s->oformat->priv_class && s->priv_data)
        av_opt_free(s->priv_data);

    for (unsigned i = 0; i < s->nb_streams; i++)
        ff_free_stream(&s->streams[i]);
    s->nb_streams = 0;

    for (unsigned i = 0; i < s->nb_programs; i++) {
        av_dict_free(&s->programs[i]->metadata);
        av_freep(&s->programs[i]->stream_index);
        av_freep(&s->programs[i]);
    }
    s->nb_programs = 0;

    av_freep(&s->programs);
    av_freep(&s->priv_data);
    while (s->nb_chapters--) {
        av_dict_free(&s->chapters[s->nb_chapters]->metadata);
        av_freep(&s->chapters[s->nb_chapters]);
    }
    av_freep(&s->chapters);
    av_dict_free(&s->metadata);
    av_dict_free(&si->id3v2_meta);
    av_packet_free(&si->pkt);
    av_packet_free(&si->parse_pkt);
    av_freep(&s->streams);
    ff_flush_packet_queue(s);
    av_freep(&s->url);
    av_free(s);
}

uint8_t *av_stream_get_side_data(const AVStream *st,
                                 enum AVPacketSideDataType type, size_t *size)
{
    for (int i = 0; i < st->nb_side_data; i++) {
        if (st->side_data[i].type == type) {
            if (size)
                *size = st->side_data[i].size;
            return st->side_data[i].data;
        }
    }
    if (size)
        *size = 0;
    return NULL;
}

int av_stream_add_side_data(AVStream *st, enum AVPacketSideDataType type,
                            uint8_t *data, size_t size)
{
    AVPacketSideData *sd, *tmp;

    for (int i = 0; i < st->nb_side_data; i++) {
        sd = &st->side_data[i];

        if (sd->type == type) {
            av_freep(&sd->data);
            sd->data = data;
            sd->size = size;
            return 0;
        }
    }

    if (st->nb_side_data + 1U > FFMIN(INT_MAX, SIZE_MAX / sizeof(*tmp)))
        return AVERROR(ERANGE);

    tmp = av_realloc_array(st->side_data, st->nb_side_data + 1, sizeof(*tmp));
    if (!tmp) {
        return AVERROR(ENOMEM);
    }

    st->side_data = tmp;
    st->nb_side_data++;

    sd = &st->side_data[st->nb_side_data - 1];
    sd->type = type;
    sd->data = data;
    sd->size = size;

    return 0;
}

uint8_t *av_stream_new_side_data(AVStream *st, enum AVPacketSideDataType type,
                                 size_t size)
{
    int ret;
    uint8_t *data = av_malloc(size);

    if (!data)
        return NULL;

    ret = av_stream_add_side_data(st, type, data, size);
    if (ret < 0) {
        av_freep(&data);
        return NULL;
    }

    return data;
}

int ff_stream_side_data_copy(AVStream *dst, const AVStream *src)
{
    /* Free existing side data*/
    for (int i = 0; i < dst->nb_side_data; i++)
        av_free(dst->side_data[i].data);
    av_freep(&dst->side_data);
    dst->nb_side_data = 0;

    /* Copy side data if present */
    if (src->nb_side_data) {
        dst->side_data = av_calloc(src->nb_side_data,
                                   sizeof(*dst->side_data));
        if (!dst->side_data)
            return AVERROR(ENOMEM);
        dst->nb_side_data = src->nb_side_data;

        for (int i = 0; i < src->nb_side_data; i++) {
            uint8_t *data = av_memdup(src->side_data[i].data,
                                      src->side_data[i].size);
            if (!data)
                return AVERROR(ENOMEM);
            dst->side_data[i].type = src->side_data[i].type;
            dst->side_data[i].size = src->side_data[i].size;
            dst->side_data[i].data = data;
        }
    }

    return 0;
}

/**
 * Copy all stream parameters from source to destination stream, with the
 * exception of the index field, which is usually set by avformat_new_stream().
 *
 * @param dst pointer to destination AVStream
 * @param src pointer to source AVStream
 * @return >=0 on success, AVERROR code on error
 */
static int stream_params_copy(AVStream *dst, const AVStream *src)
{
    int ret;

    dst->id                  = src->id;
    dst->time_base           = src->time_base;
    dst->start_time          = src->start_time;
    dst->duration            = src->duration;
    dst->nb_frames           = src->nb_frames;
    dst->disposition         = src->disposition;
    dst->discard             = src->discard;
    dst->sample_aspect_ratio = src->sample_aspect_ratio;
    dst->avg_frame_rate      = src->avg_frame_rate;
    dst->event_flags         = src->event_flags;
    dst->r_frame_rate        = src->r_frame_rate;
    dst->pts_wrap_bits       = src->pts_wrap_bits;

    av_dict_free(&dst->metadata);
    ret = av_dict_copy(&dst->metadata, src->metadata, 0);
    if (ret < 0)
        return ret;

    ret = avcodec_parameters_copy(dst->codecpar, src->codecpar);
    if (ret < 0)
        return ret;

    ret = ff_stream_side_data_copy(dst, src);
    if (ret < 0)
        return ret;

    av_packet_unref(&dst->attached_pic);
    if (src->attached_pic.data) {
        ret = av_packet_ref(&dst->attached_pic, &src->attached_pic);
        if (ret < 0)
            return ret;
    }

    return 0;
}

AVStream *ff_stream_clone(AVFormatContext *dst_ctx, const AVStream *src)
{
    AVStream *st;
    int ret;

    st = avformat_new_stream(dst_ctx, NULL);
    if (!st)
        return NULL;

    ret = stream_params_copy(st, src);
    if (ret < 0) {
        ff_remove_stream(dst_ctx, st);
        return NULL;
    }

    return st;
}

AVProgram *av_new_program(AVFormatContext *ac, int id)
{
    AVProgram *program = NULL;
    int ret;

    av_log(ac, AV_LOG_TRACE, "new_program: id=0x%04x\n", id);

    for (unsigned i = 0; i < ac->nb_programs; i++)
        if (ac->programs[i]->id == id)
            program = ac->programs[i];

    if (!program) {
        program = av_mallocz(sizeof(*program));
        if (!program)
            return NULL;
        ret = av_dynarray_add_nofree(&ac->programs, &ac->nb_programs, program);
        if (ret < 0) {
            av_free(program);
            return NULL;
        }
        program->discard = AVDISCARD_NONE;
        program->pmt_version = -1;
        program->id = id;
        program->pts_wrap_reference = AV_NOPTS_VALUE;
        program->pts_wrap_behavior = AV_PTS_WRAP_IGNORE;
        program->start_time =
        program->end_time   = AV_NOPTS_VALUE;
    }
    return program;
}

void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned idx)
{
    AVProgram *program = NULL;
    void *tmp;

    if (idx >= ac->nb_streams) {
        av_log(ac, AV_LOG_ERROR, "stream index %d is not valid\n", idx);
        return;
    }

    for (unsigned i = 0; i < ac->nb_programs; i++) {
        if (ac->programs[i]->id != progid)
            continue;
        program = ac->programs[i];
        for (unsigned j = 0; j < program->nb_stream_indexes; j++)
            if (program->stream_index[j] == idx)
                return;

        tmp = av_realloc_array(program->stream_index, program->nb_stream_indexes+1, sizeof(unsigned int));
        if (!tmp)
            return;
        program->stream_index = tmp;
        program->stream_index[program->nb_stream_indexes++] = idx;
        return;
    }
}

AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s)
{
    for (unsigned i = 0; i < ic->nb_programs; i++) {
        if (ic->programs[i] == last) {
            last = NULL;
        } else {
            if (!last)
                for (unsigned j = 0; j < ic->programs[i]->nb_stream_indexes; j++)
                    if (ic->programs[i]->stream_index[j] == s)
                        return ic->programs[i];
        }
    }
    return NULL;
}

int av_find_default_stream_index(AVFormatContext *s)
{
    int best_stream = 0;
    int best_score = INT_MIN;

    if (s->nb_streams <= 0)
        return -1;
    for (unsigned i = 0; i < s->nb_streams; i++) {
        const AVStream *const st = s->streams[i];
        const FFStream *const sti = cffstream(st);
        int score = 0;
        if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
            if (st->disposition & AV_DISPOSITION_ATTACHED_PIC)
                score -= 400;
            if (st->codecpar->width && st->codecpar->height)
                score += 50;
            score+= 25;
        }
        if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
            if (st->codecpar->sample_rate)
                score += 50;
        }
        if (sti->codec_info_nb_frames)
            score += 12;

        if (st->discard != AVDISCARD_ALL)
            score += 200;

        if (score > best_score) {
            best_score = score;
            best_stream = i;
        }
    }
    return best_stream;
}

int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type,
                        int wanted_stream_nb, int related_stream,
                        const AVCodec **decoder_ret, int flags)
{
    int nb_streams = ic->nb_streams;
    int ret = AVERROR_STREAM_NOT_FOUND;
    int best_count = -1, best_multiframe = -1, best_disposition = -1;
    int count, multiframe, disposition;
    int64_t best_bitrate = -1;
    int64_t bitrate;
    unsigned *program = NULL;
    const AVCodec *decoder = NULL, *best_decoder = NULL;

    if (related_stream >= 0 && wanted_stream_nb < 0) {
        AVProgram *p = av_find_program_from_stream(ic, NULL, related_stream);
        if (p) {
            program    = p->stream_index;
            nb_streams = p->nb_stream_indexes;
        }
    }
    for (unsigned i = 0; i < nb_streams; i++) {
        int real_stream_index = program ? program[i] : i;
        AVStream *st          = ic->streams[real_stream_index];
        AVCodecParameters *par = st->codecpar;
        if (par->codec_type != type)
            continue;
        if (wanted_stream_nb >= 0 && real_stream_index != wanted_stream_nb)
            continue;
        if (type == AVMEDIA_TYPE_AUDIO && !(par->ch_layout.nb_channels && par->sample_rate))
            continue;
        if (decoder_ret) {
            decoder = ff_find_decoder(ic, st, par->codec_id);
            if (!decoder) {
                if (ret < 0)
                    ret = AVERROR_DECODER_NOT_FOUND;
                continue;
            }
        }
        disposition = !(st->disposition & (AV_DISPOSITION_HEARING_IMPAIRED | AV_DISPOSITION_VISUAL_IMPAIRED))
                      + !! (st->disposition & AV_DISPOSITION_DEFAULT);
        count = ffstream(st)->codec_info_nb_frames;
        bitrate = par->bit_rate;
        multiframe = FFMIN(5, count);
        if ((best_disposition >  disposition) ||
            (best_disposition == disposition && best_multiframe >  multiframe) ||
            (best_disposition == disposition && best_multiframe == multiframe && best_bitrate >  bitrate) ||
            (best_disposition == disposition && best_multiframe == multiframe && best_bitrate == bitrate && best_count >= count))
            continue;
        best_disposition = disposition;
        best_count   = count;
        best_bitrate = bitrate;
        best_multiframe = multiframe;
        ret          = real_stream_index;
        best_decoder = decoder;
        if (program && i == nb_streams - 1 && ret < 0) {
            program    = NULL;
            nb_streams = ic->nb_streams;
            /* no related stream found, try again with everything */
            i = 0;
        }
    }
    if (decoder_ret)
        *decoder_ret = best_decoder;
    return ret;
}

/**
 * Matches a stream specifier (but ignores requested index).
 *
 * @param indexptr set to point to the requested stream index if there is one
 *
 * @return <0 on error
 *         0  if st is NOT a matching stream
 *         >0 if st is a matching stream
 */
static int match_stream_specifier(const AVFormatContext *s, const AVStream *st,
                                  const char *spec, const char **indexptr,
                                  const AVProgram **p)
{
    int match = 1;                      /* Stores if the specifier matches so far. */
    while (*spec) {
        if (*spec <= '9' && *spec >= '0') { /* opt:index */
            if (indexptr)
                *indexptr = spec;
            return match;
        } else if (*spec == 'v' || *spec == 'a' || *spec == 's' || *spec == 'd' ||
                   *spec == 't' || *spec == 'V') { /* opt:[vasdtV] */
            enum AVMediaType type;
            int nopic = 0;

            switch (*spec++) {
            case 'v': type = AVMEDIA_TYPE_VIDEO;      break;
            case 'a': type = AVMEDIA_TYPE_AUDIO;      break;
            case 's': type = AVMEDIA_TYPE_SUBTITLE;   break;
            case 'd': type = AVMEDIA_TYPE_DATA;       break;
            case 't': type = AVMEDIA_TYPE_ATTACHMENT; break;
            case 'V': type = AVMEDIA_TYPE_VIDEO; nopic = 1; break;
            default:  av_assert0(0);
            }
            if (*spec && *spec++ != ':')         /* If we are not at the end, then another specifier must follow. */
                return AVERROR(EINVAL);

            if (type != st->codecpar->codec_type)
                match = 0;
            if (nopic && (st->disposition & AV_DISPOSITION_ATTACHED_PIC))
                match = 0;
        } else if (*spec == 'p' && *(spec + 1) == ':') {
            int prog_id;
            int found = 0;
            char *endptr;
            spec += 2;
            prog_id = strtol(spec, &endptr, 0);
            /* Disallow empty id and make sure that if we are not at the end, then another specifier must follow. */
            if (spec == endptr || (*endptr && *endptr++ != ':'))
                return AVERROR(EINVAL);
            spec = endptr;
            if (match) {
                for (unsigned i = 0; i < s->nb_programs; i++) {
                    if (s->programs[i]->id != prog_id)
                        continue;

                    for (unsigned j = 0; j < s->programs[i]->nb_stream_indexes; j++) {
                        if (st->index == s->programs[i]->stream_index[j]) {
                            found = 1;
                            if (p)
                                *p = s->programs[i];
                            i = s->nb_programs;
                            break;
                        }
                    }
                }
            }
            if (!found)
                match = 0;
        } else if (*spec == '#' ||
                   (*spec == 'i' && *(spec + 1) == ':')) {
            int stream_id;
            char *endptr;
            spec += 1 + (*spec == 'i');
            stream_id = strtol(spec, &endptr, 0);
            if (spec == endptr || *endptr)                /* Disallow empty id and make sure we are at the end. */
                return AVERROR(EINVAL);
            return match && (stream_id == st->id);
        } else if (*spec == 'm' && *(spec + 1) == ':') {
            const AVDictionaryEntry *tag;
            char *key, *val;
            int ret;

            if (match) {
                spec += 2;
                val = strchr(spec, ':');

                key = val ? av_strndup(spec, val - spec) : av_strdup(spec);
                if (!key)
                    return AVERROR(ENOMEM);

                tag = av_dict_get(st->metadata, key, NULL, 0);
                if (tag) {
                    if (!val || !strcmp(tag->value, val + 1))
                        ret = 1;
                    else
                        ret = 0;
                } else
                    ret = 0;

                av_freep(&key);
            }
            return match && ret;
        } else if (*spec == 'u' && *(spec + 1) == '\0') {
            const AVCodecParameters *par = st->codecpar;
            int val;
            switch (par->codec_type) {
            case AVMEDIA_TYPE_AUDIO:
                val = par->sample_rate && par->ch_layout.nb_channels;
                if (par->format == AV_SAMPLE_FMT_NONE)
                    return 0;
                break;
            case AVMEDIA_TYPE_VIDEO:
                val = par->width && par->height;
                if (par->format == AV_PIX_FMT_NONE)
                    return 0;
                break;
            case AVMEDIA_TYPE_UNKNOWN:
                val = 0;
                break;
            default:
                val = 1;
                break;
            }
            return match && (par->codec_id != AV_CODEC_ID_NONE && val != 0);
        } else {
            return AVERROR(EINVAL);
        }
    }

    return match;
}

int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st,
                                    const char *spec)
{
    int ret, index;
    char *endptr;
    const char *indexptr = NULL;
    const AVProgram *p = NULL;
    int nb_streams;

    ret = match_stream_specifier(s, st, spec, &indexptr, &p);
    if (ret < 0)
        goto error;

    if (!indexptr)
        return ret;

    index = strtol(indexptr, &endptr, 0);
    if (*endptr) {                  /* We can't have anything after the requested index. */
        ret = AVERROR(EINVAL);
        goto error;
    }

    /* This is not really needed but saves us a loop for simple stream index specifiers. */
    if (spec == indexptr)
        return (index == st->index);

    /* If we requested a matching stream index, we have to ensure st is that. */
    nb_streams = p ? p->nb_stream_indexes : s->nb_streams;
    for (int i = 0; i < nb_streams && index >= 0; i++) {
        const AVStream *candidate = s->streams[p ? p->stream_index[i] : i];
        ret = match_stream_specifier(s, candidate, spec, NULL, NULL);
        if (ret < 0)
            goto error;
        if (ret > 0 && index-- == 0 && st == candidate)
            return 1;
    }
    return 0;

error:
    if (ret == AVERROR(EINVAL))
        av_log(s, AV_LOG_ERROR, "Invalid stream specifier: %s.\n", spec);
    return ret;
}

AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame)
{
    AVRational undef = {0, 1};
    AVRational stream_sample_aspect_ratio = stream ? stream->sample_aspect_ratio : undef;
    AVRational codec_sample_aspect_ratio  = stream && stream->codecpar ? stream->codecpar->sample_aspect_ratio : undef;
    AVRational frame_sample_aspect_ratio  = frame  ? frame->sample_aspect_ratio  : codec_sample_aspect_ratio;

    av_reduce(&stream_sample_aspect_ratio.num, &stream_sample_aspect_ratio.den,
               stream_sample_aspect_ratio.num,  stream_sample_aspect_ratio.den, INT_MAX);
    if (stream_sample_aspect_ratio.num <= 0 || stream_sample_aspect_ratio.den <= 0)
        stream_sample_aspect_ratio = undef;

    av_reduce(&frame_sample_aspect_ratio.num, &frame_sample_aspect_ratio.den,
               frame_sample_aspect_ratio.num,  frame_sample_aspect_ratio.den, INT_MAX);
    if (frame_sample_aspect_ratio.num <= 0 || frame_sample_aspect_ratio.den <= 0)
        frame_sample_aspect_ratio = undef;

    if (stream_sample_aspect_ratio.num)
        return stream_sample_aspect_ratio;
    else
        return frame_sample_aspect_ratio;
}

AVRational av_guess_frame_rate(AVFormatContext *format, AVStream *st, AVFrame *frame)
{
    AVRational fr = st->r_frame_rate;
    AVCodecContext *const avctx = ffstream(st)->avctx;
    AVRational codec_fr = avctx->framerate;
    AVRational   avg_fr = st->avg_frame_rate;

    if (avg_fr.num > 0 && avg_fr.den > 0 && fr.num > 0 && fr.den > 0 &&
        av_q2d(avg_fr) < 70 && av_q2d(fr) > 210) {
        fr = avg_fr;
    }

    if (avctx->ticks_per_frame > 1) {
        if (   codec_fr.num > 0 && codec_fr.den > 0 &&
            (fr.num == 0 || av_q2d(codec_fr) < av_q2d(fr)*0.7 && fabs(1.0 - av_q2d(av_div_q(avg_fr, fr))) > 0.1))
            fr = codec_fr;
    }

    return fr;
}

int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt,
                                                  AVStream *ost, const AVStream *ist,
                                                  enum AVTimebaseSource copy_tb)
{
    const AVCodecContext *const dec_ctx = cffstream(ist)->avctx;
    AVCodecContext       *const enc_ctx =  ffstream(ost)->avctx;
    AVRational dec_ctx_tb = dec_ctx->framerate.num ? av_inv_q(av_mul_q(dec_ctx->framerate,
                                                                       (AVRational){dec_ctx->ticks_per_frame, 1}))
                                                   : (ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO ? (AVRational){0, 1}
                                                                                                      : ist->time_base);

    enc_ctx->time_base = ist->time_base;
    /*
     * Avi is a special case here because it supports variable fps but
     * having the fps and timebase differe significantly adds quite some
     * overhead
     */
    if (!strcmp(ofmt->name, "avi")) {
#if FF_API_R_FRAME_RATE
        if (copy_tb == AVFMT_TBCF_AUTO && ist->r_frame_rate.num
            && av_q2d(ist->r_frame_rate) >= av_q2d(ist->avg_frame_rate)
            && 0.5/av_q2d(ist->r_frame_rate) > av_q2d(ist->time_base)
            && 0.5/av_q2d(ist->r_frame_rate) > av_q2d(dec_ctx_tb)
            && av_q2d(ist->time_base) < 1.0/500 && av_q2d(dec_ctx_tb) < 1.0/500
            || copy_tb == AVFMT_TBCF_R_FRAMERATE) {
            enc_ctx->time_base.num = ist->r_frame_rate.den;
            enc_ctx->time_base.den = 2*ist->r_frame_rate.num;
            enc_ctx->ticks_per_frame = 2;
        } else
#endif
            if (copy_tb == AVFMT_TBCF_AUTO && dec_ctx->framerate.num &&
                av_q2d(av_inv_q(dec_ctx->framerate)) > 2*av_q2d(ist->time_base)
                   && av_q2d(ist->time_base) < 1.0/500
                   || (copy_tb == AVFMT_TBCF_DECODER &&
                       (dec_ctx->framerate.num || ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO))) {
            enc_ctx->time_base = dec_ctx_tb;
            enc_ctx->time_base.num *= dec_ctx->ticks_per_frame;
            enc_ctx->time_base.den *= 2;
            enc_ctx->ticks_per_frame = 2;
        }
    } else if (!(ofmt->flags & AVFMT_VARIABLE_FPS)
               && !av_match_name(ofmt->name, "mov,mp4,3gp,3g2,psp,ipod,ismv,f4v")) {
        if (copy_tb == AVFMT_TBCF_AUTO && dec_ctx->framerate.num
            && av_q2d(av_inv_q(dec_ctx->framerate)) > av_q2d(ist->time_base)
            && av_q2d(ist->time_base) < 1.0/500
            || (copy_tb == AVFMT_TBCF_DECODER &&
                (dec_ctx->framerate.num || ist->codecpar->codec_type == AVMEDIA_TYPE_AUDIO))) {
            enc_ctx->time_base = dec_ctx_tb;
            enc_ctx->time_base.num *= dec_ctx->ticks_per_frame;
        }
    }

    if ((enc_ctx->codec_tag == AV_RL32("tmcd") || ost->codecpar->codec_tag == AV_RL32("tmcd"))
        && dec_ctx_tb.num < dec_ctx_tb.den
        && dec_ctx_tb.num > 0
        && 121LL*dec_ctx_tb.num > dec_ctx_tb.den) {
        enc_ctx->time_base = dec_ctx_tb;
    }

    av_reduce(&enc_ctx->time_base.num, &enc_ctx->time_base.den,
              enc_ctx->time_base.num, enc_ctx->time_base.den, INT_MAX);

    return 0;
}

AVRational av_stream_get_codec_timebase(const AVStream *st)
{
    // See avformat_transfer_internal_stream_timing_info() TODO.
    return cffstream(st)->avctx->time_base;
}

void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits,
                         unsigned int pts_num, unsigned int pts_den)
{
    FFStream *const sti = ffstream(st);
    AVRational new_tb;
    if (av_reduce(&new_tb.num, &new_tb.den, pts_num, pts_den, INT_MAX)) {
        if (new_tb.num != pts_num)
            av_log(NULL, AV_LOG_DEBUG,
                   "st:%d removing common factor %d from timebase\n",
                   st->index, pts_num / new_tb.num);
    } else
        av_log(NULL, AV_LOG_WARNING,
               "st:%d has too large timebase, reducing\n", st->index);

    if (new_tb.num <= 0 || new_tb.den <= 0) {
        av_log(NULL, AV_LOG_ERROR,
               "Ignoring attempt to set invalid timebase %d/%d for st:%d\n",
               new_tb.num, new_tb.den,
               st->index);
        return;
    }
    st->time_base     = new_tb;
    sti->avctx->pkt_timebase = new_tb;
    st->pts_wrap_bits = pts_wrap_bits;
}

const AVCodec *ff_find_decoder(AVFormatContext *s, const AVStream *st,
                               enum AVCodecID codec_id)
{
    switch (st->codecpar->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        if (s->video_codec)    return s->video_codec;
        break;
    case AVMEDIA_TYPE_AUDIO:
        if (s->audio_codec)    return s->audio_codec;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        if (s->subtitle_codec) return s->subtitle_codec;
        break;
    }

    return avcodec_find_decoder(codec_id);
}

int ff_copy_whiteblacklists(AVFormatContext *dst, const AVFormatContext *src)
{
    av_assert0(!dst->codec_whitelist &&
               !dst->format_whitelist &&
               !dst->protocol_whitelist &&
               !dst->protocol_blacklist);
    dst-> codec_whitelist = av_strdup(src->codec_whitelist);
    dst->format_whitelist = av_strdup(src->format_whitelist);
    dst->protocol_whitelist = av_strdup(src->protocol_whitelist);
    dst->protocol_blacklist = av_strdup(src->protocol_blacklist);
    if (   (src-> codec_whitelist && !dst-> codec_whitelist)
        || (src->  format_whitelist && !dst->  format_whitelist)
        || (src->protocol_whitelist && !dst->protocol_whitelist)
        || (src->protocol_blacklist && !dst->protocol_blacklist)) {
        av_log(dst, AV_LOG_ERROR, "Failed to duplicate black/whitelist\n");
        return AVERROR(ENOMEM);
    }
    return 0;
}

int ff_is_intra_only(enum AVCodecID id)
{
    const AVCodecDescriptor *d = avcodec_descriptor_get(id);
    if (!d)
        return 0;
    if ((d->type == AVMEDIA_TYPE_VIDEO || d->type == AVMEDIA_TYPE_AUDIO) &&
        !(d->props & AV_CODEC_PROP_INTRA_ONLY))
        return 0;
    return 1;
}

void ff_format_set_url(AVFormatContext *s, char *url)
{
    av_assert0(url);
    av_freep(&s->url);
    s->url = url;
}

int ff_format_io_close(AVFormatContext *s, AVIOContext **pb)
{
    int ret = 0;
    if (*pb) {
#if FF_API_AVFORMAT_IO_CLOSE
FF_DISABLE_DEPRECATION_WARNINGS
        if (s->io_close == ff_format_io_close_default || s->io_close == NULL)
#endif
            ret = s->io_close2(s, *pb);
#if FF_API_AVFORMAT_IO_CLOSE
        else
            s->io_close(s, *pb);
FF_ENABLE_DEPRECATION_WARNINGS
#endif
    }
    *pb = NULL;
    return ret;
}