aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/mux.c
blob: aa5d5edebc92deee7dc8bb31752409aafbde7cc4 (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
/*
 * muxing functions for use within FFmpeg
 * 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 "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#include "libavcodec/internal.h"
#include "libavcodec/bytestream.h"
#include "libavutil/opt.h"
#include "libavutil/dict.h"
#include "libavutil/pixdesc.h"
#include "libavutil/timestamp.h"
#include "metadata.h"
#include "id3v2.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/parseutils.h"
#include "libavutil/time.h"
#include "riff.h"
#include "audiointerleave.h"
#include "url.h"
#include <stdarg.h>
#if CONFIG_NETWORK
#include "network.h"
#endif

#undef NDEBUG
#include <assert.h>

/**
 * @file
 * muxing functions for use within libavformat
 */

/* fraction handling */

/**
 * f = val + (num / den) + 0.5.
 *
 * 'num' is normalized so that it is such as 0 <= num < den.
 *
 * @param f fractional number
 * @param val integer value
 * @param num must be >= 0
 * @param den must be >= 1
 */
static void frac_init(AVFrac *f, int64_t val, int64_t num, int64_t den)
{
    num += (den >> 1);
    if (num >= den) {
        val += num / den;
        num  = num % den;
    }
    f->val = val;
    f->num = num;
    f->den = den;
}

/**
 * Fractional addition to f: f = f + (incr / f->den).
 *
 * @param f fractional number
 * @param incr increment, can be positive or negative
 */
static void frac_add(AVFrac *f, int64_t incr)
{
    int64_t num, den;

    num = f->num + incr;
    den = f->den;
    if (num < 0) {
        f->val += num / den;
        num     = num % den;
        if (num < 0) {
            num += den;
            f->val--;
        }
    } else if (num >= den) {
        f->val += num / den;
        num     = num % den;
    }
    f->num = num;
}

AVRational ff_choose_timebase(AVFormatContext *s, AVStream *st, int min_precission)
{
    AVRational q;
    int j;

    if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
        q = (AVRational){1, st->codec->sample_rate};
    } else {
        q = st->codec->time_base;
    }
    for (j=2; j<14; j+= 1+(j>2))
        while (q.den / q.num < min_precission && q.num % j == 0)
            q.num /= j;
    while (q.den / q.num < min_precission && q.den < (1<<24))
        q.den <<= 1;

    return q;
}

int avformat_alloc_output_context2(AVFormatContext **avctx, AVOutputFormat *oformat,
                                   const char *format, const char *filename)
{
    AVFormatContext *s = avformat_alloc_context();
    int ret = 0;

    *avctx = NULL;
    if (!s)
        goto nomem;

    if (!oformat) {
        if (format) {
            oformat = av_guess_format(format, NULL, NULL);
            if (!oformat) {
                av_log(s, AV_LOG_ERROR, "Requested output format '%s' is not a suitable output format\n", format);
                ret = AVERROR(EINVAL);
                goto error;
            }
        } else {
            oformat = av_guess_format(NULL, filename, NULL);
            if (!oformat) {
                ret = AVERROR(EINVAL);
                av_log(s, AV_LOG_ERROR, "Unable to find a suitable output format for '%s'\n",
                       filename);
                goto error;
            }
        }
    }

    s->oformat = oformat;
    if (s->oformat->priv_data_size > 0) {
        s->priv_data = av_mallocz(s->oformat->priv_data_size);
        if (!s->priv_data)
            goto nomem;
        if (s->oformat->priv_class) {
            *(const AVClass**)s->priv_data= s->oformat->priv_class;
            av_opt_set_defaults(s->priv_data);
        }
    } else
        s->priv_data = NULL;

    if (filename)
        av_strlcpy(s->filename, filename, sizeof(s->filename));
    *avctx = s;
    return 0;
nomem:
    av_log(s, AV_LOG_ERROR, "Out of memory\n");
    ret = AVERROR(ENOMEM);
error:
    avformat_free_context(s);
    return ret;
}

#if FF_API_ALLOC_OUTPUT_CONTEXT
AVFormatContext *avformat_alloc_output_context(const char *format,
                                               AVOutputFormat *oformat, const char *filename)
{
    AVFormatContext *avctx;
    int ret = avformat_alloc_output_context2(&avctx, oformat, format, filename);
    return ret < 0 ? NULL : avctx;
}
#endif

static int validate_codec_tag(AVFormatContext *s, AVStream *st)
{
    const AVCodecTag *avctag;
    int n;
    enum AVCodecID id = AV_CODEC_ID_NONE;
    unsigned int tag  = 0;

    /**
     * Check that tag + id is in the table
     * If neither is in the table -> OK
     * If tag is in the table with another id -> FAIL
     * If id is in the table with another tag -> FAIL unless strict < normal
     */
    for (n = 0; s->oformat->codec_tag[n]; n++) {
        avctag = s->oformat->codec_tag[n];
        while (avctag->id != AV_CODEC_ID_NONE) {
            if (avpriv_toupper4(avctag->tag) == avpriv_toupper4(st->codec->codec_tag)) {
                id = avctag->id;
                if (id == st->codec->codec_id)
                    return 1;
            }
            if (avctag->id == st->codec->codec_id)
                tag = avctag->tag;
            avctag++;
        }
    }
    if (id != AV_CODEC_ID_NONE)
        return 0;
    if (tag && (st->codec->strict_std_compliance >= FF_COMPLIANCE_NORMAL))
        return 0;
    return 1;
}


static int init_muxer(AVFormatContext *s, AVDictionary **options)
{
    int ret = 0, i;
    AVStream *st;
    AVDictionary *tmp = NULL;
    AVCodecContext *codec = NULL;
    AVOutputFormat *of = s->oformat;

    if (options)
        av_dict_copy(&tmp, *options, 0);

    if ((ret = av_opt_set_dict(s, &tmp)) < 0)
        goto fail;
    if (s->priv_data && s->oformat->priv_class && *(const AVClass**)s->priv_data==s->oformat->priv_class &&
        (ret = av_opt_set_dict(s->priv_data, &tmp)) < 0)
        goto fail;

    // some sanity checks
    if (s->nb_streams == 0 && !(of->flags & AVFMT_NOSTREAMS)) {
        av_log(s, AV_LOG_ERROR, "no streams\n");
        ret = AVERROR(EINVAL);
        goto fail;
    }

    for (i = 0; i < s->nb_streams; i++) {
        st    = s->streams[i];
        codec = st->codec;

        switch (codec->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            if (codec->sample_rate <= 0) {
                av_log(s, AV_LOG_ERROR, "sample rate not set\n");
                ret = AVERROR(EINVAL);
                goto fail;
            }
            if (!codec->block_align)
                codec->block_align = codec->channels *
                                     av_get_bits_per_sample(codec->codec_id) >> 3;
            break;
        case AVMEDIA_TYPE_VIDEO:
            if (codec->time_base.num <= 0 ||
                codec->time_base.den <= 0) { //FIXME audio too?
                av_log(s, AV_LOG_ERROR, "time base not set\n");
                ret = AVERROR(EINVAL);
                goto fail;
            }

            if ((codec->width <= 0 || codec->height <= 0) &&
                !(of->flags & AVFMT_NODIMENSIONS)) {
                av_log(s, AV_LOG_ERROR, "dimensions not set\n");
                ret = AVERROR(EINVAL);
                goto fail;
            }
            if (av_cmp_q(st->sample_aspect_ratio, codec->sample_aspect_ratio)
                && FFABS(av_q2d(st->sample_aspect_ratio) - av_q2d(codec->sample_aspect_ratio)) > 0.004*av_q2d(st->sample_aspect_ratio)
            ) {
                if (st->sample_aspect_ratio.num != 0 &&
                    st->sample_aspect_ratio.den != 0 &&
                    codec->sample_aspect_ratio.den != 0 &&
                    codec->sample_aspect_ratio.den != 0) {
                    av_log(s, AV_LOG_ERROR, "Aspect ratio mismatch between muxer "
                           "(%d/%d) and encoder layer (%d/%d)\n",
                           st->sample_aspect_ratio.num, st->sample_aspect_ratio.den,
                           codec->sample_aspect_ratio.num,
                           codec->sample_aspect_ratio.den);
                    ret = AVERROR(EINVAL);
                    goto fail;
                }
            }
            break;
        }

        if (of->codec_tag) {
            if (   codec->codec_tag
                && codec->codec_id == AV_CODEC_ID_RAWVIDEO
                && (   av_codec_get_tag(of->codec_tag, codec->codec_id) == 0
                    || av_codec_get_tag(of->codec_tag, codec->codec_id) == MKTAG('r', 'a', 'w', ' '))
                && !validate_codec_tag(s, st)) {
                // the current rawvideo encoding system ends up setting
                // the wrong codec_tag for avi/mov, we override it here
                codec->codec_tag = 0;
            }
            if (codec->codec_tag) {
                if (!validate_codec_tag(s, st)) {
                    char tagbuf[32], tagbuf2[32];
                    av_get_codec_tag_string(tagbuf, sizeof(tagbuf), codec->codec_tag);
                    av_get_codec_tag_string(tagbuf2, sizeof(tagbuf2), av_codec_get_tag(s->oformat->codec_tag, codec->codec_id));
                    av_log(s, AV_LOG_ERROR,
                           "Tag %s/0x%08x incompatible with output codec id '%d' (%s)\n",
                           tagbuf, codec->codec_tag, codec->codec_id, tagbuf2);
                    ret = AVERROR_INVALIDDATA;
                    goto fail;
                }
            } else
                codec->codec_tag = av_codec_get_tag(of->codec_tag, codec->codec_id);
        }

        if (of->flags & AVFMT_GLOBALHEADER &&
            !(codec->flags & CODEC_FLAG_GLOBAL_HEADER))
            av_log(s, AV_LOG_WARNING,
                   "Codec for stream %d does not use global headers "
                   "but container format requires global headers\n", i);
    }

    if (!s->priv_data && of->priv_data_size > 0) {
        s->priv_data = av_mallocz(of->priv_data_size);
        if (!s->priv_data) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        if (of->priv_class) {
            *(const AVClass **)s->priv_data = of->priv_class;
            av_opt_set_defaults(s->priv_data);
            if ((ret = av_opt_set_dict(s->priv_data, &tmp)) < 0)
                goto fail;
        }
    }

    /* set muxer identification string */
    if (s->nb_streams && !(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
        av_dict_set(&s->metadata, "encoder", LIBAVFORMAT_IDENT, 0);
    }

    if (options) {
         av_dict_free(options);
         *options = tmp;
    }

    return 0;

fail:
    av_dict_free(&tmp);
    return ret;
}

static int init_pts(AVFormatContext *s)
{
    int i;
    AVStream *st;

    /* init PTS generation */
    for (i = 0; i < s->nb_streams; i++) {
        int64_t den = AV_NOPTS_VALUE;
        st = s->streams[i];

        switch (st->codec->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            den = (int64_t)st->time_base.num * st->codec->sample_rate;
            break;
        case AVMEDIA_TYPE_VIDEO:
            den = (int64_t)st->time_base.num * st->codec->time_base.den;
            break;
        default:
            break;
        }
        if (den != AV_NOPTS_VALUE) {
            if (den <= 0)
                return AVERROR_INVALIDDATA;

            frac_init(&st->pts, 0, 0, den);
        }
    }

    return 0;
}

int avformat_write_header(AVFormatContext *s, AVDictionary **options)
{
    int ret = 0;

    if (ret = init_muxer(s, options))
        return ret;

    if (s->oformat->write_header) {
        ret = s->oformat->write_header(s);
        if (ret >= 0 && s->pb && s->pb->error < 0)
            ret = s->pb->error;
        if (ret < 0)
            return ret;
    }

    if ((ret = init_pts(s)) < 0)
        return ret;

    if (s->avoid_negative_ts < 0) {
        if (s->oformat->flags & (AVFMT_TS_NEGATIVE | AVFMT_NOTIMESTAMPS)) {
            s->avoid_negative_ts = 0;
        } else
            s->avoid_negative_ts = 1;
    }

    return 0;
}

//FIXME merge with compute_pkt_fields
static int compute_pkt_fields2(AVFormatContext *s, AVStream *st, AVPacket *pkt)
{
    int delay = FFMAX(st->codec->has_b_frames, st->codec->max_b_frames > 0);
    int num, den, frame_size, i;

    av_dlog(s, "compute_pkt_fields2: pts:%s dts:%s cur_dts:%s b:%d size:%d st:%d\n",
            av_ts2str(pkt->pts), av_ts2str(pkt->dts), av_ts2str(st->cur_dts), delay, pkt->size, pkt->stream_index);

    /* duration field */
    if (pkt->duration == 0) {
        ff_compute_frame_duration(&num, &den, st, NULL, pkt);
        if (den && num) {
            pkt->duration = av_rescale(1, num * (int64_t)st->time_base.den * st->codec->ticks_per_frame, den * (int64_t)st->time_base.num);
        }
    }

    if (pkt->pts == AV_NOPTS_VALUE && pkt->dts != AV_NOPTS_VALUE && delay == 0)
        pkt->pts = pkt->dts;

    //XXX/FIXME this is a temporary hack until all encoders output pts
    if ((pkt->pts == 0 || pkt->pts == AV_NOPTS_VALUE) && pkt->dts == AV_NOPTS_VALUE && !delay) {
        static int warned;
        if (!warned) {
            av_log(s, AV_LOG_WARNING, "Encoder did not produce proper pts, making some up.\n");
            warned = 1;
        }
        pkt->dts =
//        pkt->pts= st->cur_dts;
            pkt->pts = st->pts.val;
    }

    //calculate dts from pts
    if (pkt->pts != AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE && delay <= MAX_REORDER_DELAY) {
        st->pts_buffer[0] = pkt->pts;
        for (i = 1; i < delay + 1 && st->pts_buffer[i] == AV_NOPTS_VALUE; i++)
            st->pts_buffer[i] = pkt->pts + (i - delay - 1) * pkt->duration;
        for (i = 0; i<delay && st->pts_buffer[i] > st->pts_buffer[i + 1]; i++)
            FFSWAP(int64_t, st->pts_buffer[i], st->pts_buffer[i + 1]);

        pkt->dts = st->pts_buffer[0];
    }

    if (st->cur_dts && st->cur_dts != AV_NOPTS_VALUE &&
        ((!(s->oformat->flags & AVFMT_TS_NONSTRICT) &&
          st->cur_dts >= pkt->dts) || st->cur_dts > pkt->dts)) {
        av_log(s, AV_LOG_ERROR,
               "Application provided invalid, non monotonically increasing dts to muxer in stream %d: %s >= %s\n",
               st->index, av_ts2str(st->cur_dts), av_ts2str(pkt->dts));
        return AVERROR(EINVAL);
    }
    if (pkt->dts != AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE && pkt->pts < pkt->dts) {
        av_log(s, AV_LOG_ERROR, "pts (%s) < dts (%s) in stream %d\n",
               av_ts2str(pkt->pts), av_ts2str(pkt->dts), st->index);
        return AVERROR(EINVAL);
    }

    av_dlog(s, "av_write_frame: pts2:%s dts2:%s\n",
            av_ts2str(pkt->pts), av_ts2str(pkt->dts));
    st->cur_dts = pkt->dts;
    st->pts.val = pkt->dts;

    /* update pts */
    switch (st->codec->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        frame_size = ff_get_audio_frame_size(st->codec, pkt->size, 1);

        /* HACK/FIXME, we skip the initial 0 size packets as they are most
         * likely equal to the encoder delay, but it would be better if we
         * had the real timestamps from the encoder */
        if (frame_size >= 0 && (pkt->size || st->pts.num != st->pts.den >> 1 || st->pts.val)) {
            frac_add(&st->pts, (int64_t)st->time_base.den * frame_size);
        }
        break;
    case AVMEDIA_TYPE_VIDEO:
        frac_add(&st->pts, (int64_t)st->time_base.den * st->codec->time_base.num);
        break;
    default:
        break;
    }
    return 0;
}

/**
 * Make timestamps non negative, move side data from payload to internal struct, call muxer, and restore
 * sidedata.
 *
 * FIXME: this function should NEVER get undefined pts/dts beside when the
 * AVFMT_NOTIMESTAMPS is set.
 * Those additional safety checks should be dropped once the correct checks
 * are set in the callers.
 */
static int write_packet(AVFormatContext *s, AVPacket *pkt)
{
    int ret, did_split;

    if (s->avoid_negative_ts > 0) {
        AVStream *st = s->streams[pkt->stream_index];
        int64_t offset = st->mux_ts_offset;

        if (pkt->dts < 0 && pkt->dts != AV_NOPTS_VALUE && !s->offset) {
            s->offset = -pkt->dts;
            s->offset_timebase = st->time_base;
        }

        if (s->offset && !offset) {
            offset = st->mux_ts_offset =
                av_rescale_q_rnd(s->offset,
                                 s->offset_timebase,
                                 st->time_base,
                                 AV_ROUND_UP);
        }

        if (pkt->dts != AV_NOPTS_VALUE)
            pkt->dts += offset;
        if (pkt->pts != AV_NOPTS_VALUE)
            pkt->pts += offset;

        av_assert2(pkt->dts == AV_NOPTS_VALUE || pkt->dts >= 0);
    }

    did_split = av_packet_split_side_data(pkt);
    ret = s->oformat->write_packet(s, pkt);
    if (s->flush_packets && s->pb && s->pb->error >= 0)
        avio_flush(s->pb);
    if (did_split)
        av_packet_merge_side_data(pkt);
    return ret;
}

int av_write_frame(AVFormatContext *s, AVPacket *pkt)
{
    int ret;

    if (!pkt) {
        if (s->oformat->flags & AVFMT_ALLOW_FLUSH) {
            ret = s->oformat->write_packet(s, NULL);
            if (s->flush_packets && s->pb && s->pb->error >= 0)
                avio_flush(s->pb);
            if (ret >= 0 && s->pb && s->pb->error < 0)
                ret = s->pb->error;
            return ret;
        }
        return 1;
    }

    ret = compute_pkt_fields2(s, s->streams[pkt->stream_index], pkt);

    if (ret < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
        return ret;

    ret = write_packet(s, pkt);
    if (ret >= 0 && s->pb && s->pb->error < 0)
        ret = s->pb->error;

    if (ret >= 0)
        s->streams[pkt->stream_index]->nb_frames++;
    return ret;
}

#define CHUNK_START 0x1000

int ff_interleave_add_packet(AVFormatContext *s, AVPacket *pkt,
                              int (*compare)(AVFormatContext *, AVPacket *, AVPacket *))
{
    AVPacketList **next_point, *this_pktl;
    AVStream *st   = s->streams[pkt->stream_index];
    int chunked    = s->max_chunk_size || s->max_chunk_duration;

    this_pktl      = av_mallocz(sizeof(AVPacketList));
    if (!this_pktl)
        return AVERROR(ENOMEM);
    this_pktl->pkt = *pkt;
#if FF_API_DESTRUCT_PACKET
FF_DISABLE_DEPRECATION_WARNINGS
    pkt->destruct  = NULL;           // do not free original but only the copy
FF_ENABLE_DEPRECATION_WARNINGS
#endif
    pkt->buf       = NULL;
    av_dup_packet(&this_pktl->pkt);  // duplicate the packet if it uses non-allocated memory
    av_copy_packet_side_data(&this_pktl->pkt, &this_pktl->pkt); // copy side data

    if (s->streams[pkt->stream_index]->last_in_packet_buffer) {
        next_point = &(st->last_in_packet_buffer->next);
    } else {
        next_point = &s->packet_buffer;
    }

    if (chunked) {
        uint64_t max= av_rescale_q_rnd(s->max_chunk_duration, AV_TIME_BASE_Q, st->time_base, AV_ROUND_UP);
        st->interleaver_chunk_size     += pkt->size;
        st->interleaver_chunk_duration += pkt->duration;
        if (   (s->max_chunk_size && st->interleaver_chunk_size > s->max_chunk_size)
            || (max && st->interleaver_chunk_duration           > max)) {
            st->interleaver_chunk_size      = 0;
            this_pktl->pkt.flags |= CHUNK_START;
            if (max && st->interleaver_chunk_duration > max) {
                int64_t syncoffset = (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)*max/2;
                int64_t syncto = av_rescale(pkt->dts + syncoffset, 1, max)*max - syncoffset;

                st->interleaver_chunk_duration += (pkt->dts - syncto)/8 - max;
            } else
                st->interleaver_chunk_duration = 0;
        }
    }
    if (*next_point) {
        if (chunked && !(this_pktl->pkt.flags & CHUNK_START))
            goto next_non_null;

        if (compare(s, &s->packet_buffer_end->pkt, pkt)) {
            while (   *next_point
                   && ((chunked && !((*next_point)->pkt.flags&CHUNK_START))
                       || !compare(s, &(*next_point)->pkt, pkt)))
                next_point = &(*next_point)->next;
            if (*next_point)
                goto next_non_null;
        } else {
            next_point = &(s->packet_buffer_end->next);
        }
    }
    av_assert1(!*next_point);

    s->packet_buffer_end = this_pktl;
next_non_null:

    this_pktl->next = *next_point;

    s->streams[pkt->stream_index]->last_in_packet_buffer =
        *next_point                                      = this_pktl;
    return 0;
}

static int interleave_compare_dts(AVFormatContext *s, AVPacket *next,
                                  AVPacket *pkt)
{
    AVStream *st  = s->streams[pkt->stream_index];
    AVStream *st2 = s->streams[next->stream_index];
    int comp      = av_compare_ts(next->dts, st2->time_base, pkt->dts,
                                  st->time_base);
    if (s->audio_preload && ((st->codec->codec_type == AVMEDIA_TYPE_AUDIO) != (st2->codec->codec_type == AVMEDIA_TYPE_AUDIO))) {
        int64_t ts = av_rescale_q(pkt ->dts, st ->time_base, AV_TIME_BASE_Q) - s->audio_preload*(st ->codec->codec_type == AVMEDIA_TYPE_AUDIO);
        int64_t ts2= av_rescale_q(next->dts, st2->time_base, AV_TIME_BASE_Q) - s->audio_preload*(st2->codec->codec_type == AVMEDIA_TYPE_AUDIO);
        if (ts == ts2) {
            ts= ( pkt ->dts* st->time_base.num*AV_TIME_BASE - s->audio_preload*(int64_t)(st ->codec->codec_type == AVMEDIA_TYPE_AUDIO)* st->time_base.den)*st2->time_base.den
               -( next->dts*st2->time_base.num*AV_TIME_BASE - s->audio_preload*(int64_t)(st2->codec->codec_type == AVMEDIA_TYPE_AUDIO)*st2->time_base.den)* st->time_base.den;
            ts2=0;
        }
        comp= (ts>ts2) - (ts<ts2);
    }

    if (comp == 0)
        return pkt->stream_index < next->stream_index;
    return comp > 0;
}

int ff_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out,
                                 AVPacket *pkt, int flush)
{
    AVPacketList *pktl;
    int stream_count = 0, noninterleaved_count = 0;
    int64_t delta_dts_max = 0;
    int i, ret;

    if (pkt) {
        ret = ff_interleave_add_packet(s, pkt, interleave_compare_dts);
        if (ret < 0)
            return ret;
    }

    for (i = 0; i < s->nb_streams; i++) {
        if (s->streams[i]->last_in_packet_buffer) {
            ++stream_count;
        } else if (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {
            ++noninterleaved_count;
        }
    }

    if (s->nb_streams == stream_count) {
        flush = 1;
    } else if (!flush) {
        for (i=0; i < s->nb_streams; i++) {
            if (s->streams[i]->last_in_packet_buffer) {
                int64_t delta_dts =
                    av_rescale_q(s->streams[i]->last_in_packet_buffer->pkt.dts,
                                s->streams[i]->time_base,
                                AV_TIME_BASE_Q) -
                    av_rescale_q(s->packet_buffer->pkt.dts,
                                s->streams[s->packet_buffer->pkt.stream_index]->time_base,
                                AV_TIME_BASE_Q);
                delta_dts_max= FFMAX(delta_dts_max, delta_dts);
            }
        }
        if (s->nb_streams == stream_count+noninterleaved_count &&
           delta_dts_max > 20*AV_TIME_BASE) {
            av_log(s, AV_LOG_DEBUG, "flushing with %d noninterleaved\n", noninterleaved_count);
            flush = 1;
        }
    }
    if (stream_count && flush) {
        AVStream *st;
        pktl = s->packet_buffer;
        *out = pktl->pkt;
        st   = s->streams[out->stream_index];

        s->packet_buffer = pktl->next;
        if (!s->packet_buffer)
            s->packet_buffer_end = NULL;

        if (st->last_in_packet_buffer == pktl)
            st->last_in_packet_buffer = NULL;
        av_freep(&pktl);

        return 1;
    } else {
        av_init_packet(out);
        return 0;
    }
}

/**
 * Interleave an AVPacket correctly so it can be muxed.
 * @param out the interleaved packet will be output here
 * @param in the input packet
 * @param flush 1 if no further packets are available as input and all
 *              remaining packets should be output
 * @return 1 if a packet was output, 0 if no packet could be output,
 *         < 0 if an error occurred
 */
static int interleave_packet(AVFormatContext *s, AVPacket *out, AVPacket *in, int flush)
{
    if (s->oformat->interleave_packet) {
        int ret = s->oformat->interleave_packet(s, out, in, flush);
        if (in)
            av_free_packet(in);
        return ret;
    } else
        return ff_interleave_packet_per_dts(s, out, in, flush);
}

int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt)
{
    int ret, flush = 0;

    if (pkt) {
        AVStream *st = s->streams[pkt->stream_index];

        //FIXME/XXX/HACK drop zero sized packets
        if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && pkt->size == 0)
            return 0;

        av_dlog(s, "av_interleaved_write_frame size:%d dts:%s pts:%s\n",
                pkt->size, av_ts2str(pkt->dts), av_ts2str(pkt->pts));
        if ((ret = compute_pkt_fields2(s, st, pkt)) < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
            return ret;

        if (pkt->dts == AV_NOPTS_VALUE && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
            return AVERROR(EINVAL);
    } else {
        av_dlog(s, "av_interleaved_write_frame FLUSH\n");
        flush = 1;
    }

    for (;; ) {
        AVPacket opkt;
        int ret = interleave_packet(s, &opkt, pkt, flush);
        if (ret <= 0) //FIXME cleanup needed for ret<0 ?
            return ret;

        ret = write_packet(s, &opkt);
        if (ret >= 0)
            s->streams[opkt.stream_index]->nb_frames++;

        av_free_packet(&opkt);
        pkt = NULL;

        if (ret < 0)
            return ret;
        if(s->pb && s->pb->error)
            return s->pb->error;
    }
}

int av_write_trailer(AVFormatContext *s)
{
    int ret, i;

    for (;; ) {
        AVPacket pkt;
        ret = interleave_packet(s, &pkt, NULL, 1);
        if (ret < 0) //FIXME cleanup needed for ret<0 ?
            goto fail;
        if (!ret)
            break;

        ret = write_packet(s, &pkt);
        if (ret >= 0)
            s->streams[pkt.stream_index]->nb_frames++;

        av_free_packet(&pkt);

        if (ret < 0)
            goto fail;
        if(s->pb && s->pb->error)
            goto fail;
    }

    if (s->oformat->write_trailer)
        ret = s->oformat->write_trailer(s);

fail:
    if (s->pb)
       avio_flush(s->pb);
    if (ret == 0)
       ret = s->pb ? s->pb->error : 0;
    for (i = 0; i < s->nb_streams; i++) {
        av_freep(&s->streams[i]->priv_data);
        av_freep(&s->streams[i]->index_entries);
    }
    if (s->oformat->priv_class)
        av_opt_free(s->priv_data);
    av_freep(&s->priv_data);
    return ret;
}

int av_get_output_timestamp(struct AVFormatContext *s, int stream,
                            int64_t *dts, int64_t *wall)
{
    if (!s->oformat || !s->oformat->get_output_timestamp)
        return AVERROR(ENOSYS);
    s->oformat->get_output_timestamp(s, stream, dts, wall);
    return 0;
}

int ff_write_chained(AVFormatContext *dst, int dst_stream, AVPacket *pkt,
                     AVFormatContext *src)
{
    AVPacket local_pkt;

    local_pkt = *pkt;
    local_pkt.stream_index = dst_stream;
    if (pkt->pts != AV_NOPTS_VALUE)
        local_pkt.pts = av_rescale_q(pkt->pts,
                                     src->streams[pkt->stream_index]->time_base,
                                     dst->streams[dst_stream]->time_base);
    if (pkt->dts != AV_NOPTS_VALUE)
        local_pkt.dts = av_rescale_q(pkt->dts,
                                     src->streams[pkt->stream_index]->time_base,
                                     dst->streams[dst_stream]->time_base);
    if (pkt->duration)
        local_pkt.duration = av_rescale_q(pkt->duration,
                                          src->streams[pkt->stream_index]->time_base,
                                          dst->streams[dst_stream]->time_base);
    return av_write_frame(dst, &local_pkt);
}