aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/segment.c
blob: 13d8c43589cccab10537ad493bccf7afed8af099 (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
/*
 * Copyright (c) 2011, Luca Barbato
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file generic segmenter
 * M3U8 specification can be find here:
 * @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming}
 */

/* #define DEBUG */

#include <float.h>

#include "avformat.h"
#include "internal.h"

#include "libavutil/avassert.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "libavutil/avstring.h"
#include "libavutil/parseutils.h"
#include "libavutil/mathematics.h"
#include "libavutil/timestamp.h"

typedef struct SegmentListEntry {
    int index;
    double start_time, end_time;
    int64_t start_pts;
    char filename[1024];
    struct SegmentListEntry *next;
} SegmentListEntry;

typedef enum {
    LIST_TYPE_UNDEFINED = -1,
    LIST_TYPE_FLAT = 0,
    LIST_TYPE_CSV,
    LIST_TYPE_M3U8,
    LIST_TYPE_EXT, ///< deprecated
    LIST_TYPE_NB,
} ListType;

#define SEGMENT_LIST_FLAG_CACHE 1
#define SEGMENT_LIST_FLAG_LIVE  2

typedef struct {
    const AVClass *class;  /**< Class for private options. */
    int segment_idx;       ///< index of the segment file to write, starting from 0
    int segment_idx_wrap;  ///< number after which the index wraps
    int segment_count;     ///< number of segment files already written
    AVOutputFormat *oformat;
    AVFormatContext *avf;
    char *format;          ///< format to use for output segment files
    char *list;            ///< filename for the segment list file
    int   list_flags;      ///< flags affecting list generation
    int   list_size;       ///< number of entries for the segment list file
    ListType list_type;    ///< set the list type
    AVIOContext *list_pb;  ///< list file put-byte context
    char *time_str;        ///< segment duration specification string
    int64_t time;          ///< segment duration

    char *times_str;       ///< segment times specification string
    int64_t *times;        ///< list of segment interval specification
    int nb_times;          ///< number of elments in the times array

    char *frames_str;      ///< segment frame numbers specification string
    int *frames;           ///< list of frame number specification
    int nb_frames;         ///< number of elments in the frames array
    int frame_count;

    char *time_delta_str;  ///< approximation value duration used for the segment times
    int64_t time_delta;
    int  individual_header_trailer; /**< Set by a private option. */
    int  write_header_trailer; /**< Set by a private option. */

    int reset_timestamps;  ///< reset timestamps at the begin of each segment
    char *reference_stream_specifier; ///< reference stream specifier
    int   reference_stream_index;

    SegmentListEntry cur_entry;
    SegmentListEntry *segment_list_entries;
    SegmentListEntry *segment_list_entries_end;

    int is_first_pkt;      ///< tells if it is the first packet in the segment
} SegmentContext;

static void print_csv_escaped_str(AVIOContext *ctx, const char *str)
{
    int needs_quoting = !!str[strcspn(str, "\",\n\r")];

    if (needs_quoting)
        avio_w8(ctx, '"');

    for (; *str; str++) {
        if (*str == '"')
            avio_w8(ctx, '"');
        avio_w8(ctx, *str);
    }
    if (needs_quoting)
        avio_w8(ctx, '"');
}

static int segment_mux_init(AVFormatContext *s)
{
    SegmentContext *seg = s->priv_data;
    AVFormatContext *oc;
    int i;

    seg->avf = oc = avformat_alloc_context();
    if (!oc)
        return AVERROR(ENOMEM);

    oc->oformat            = seg->oformat;
    oc->interrupt_callback = s->interrupt_callback;

    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st;
        AVCodecContext *icodec, *ocodec;

        if (!(st = avformat_new_stream(oc, NULL)))
            return AVERROR(ENOMEM);
        icodec = s->streams[i]->codec;
        ocodec = st->codec;
        avcodec_copy_context(ocodec, icodec);
        if (!oc->oformat->codec_tag ||
            av_codec_get_id (oc->oformat->codec_tag, icodec->codec_tag) == ocodec->codec_id ||
            av_codec_get_tag(oc->oformat->codec_tag, icodec->codec_id) <= 0) {
            ocodec->codec_tag = icodec->codec_tag;
        } else {
            ocodec->codec_tag = 0;
        }
        st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
    }

    return 0;
}

static int set_segment_filename(AVFormatContext *s)
{
    SegmentContext *seg = s->priv_data;
    AVFormatContext *oc = seg->avf;

    if (seg->segment_idx_wrap)
        seg->segment_idx %= seg->segment_idx_wrap;
    if (av_get_frame_filename(oc->filename, sizeof(oc->filename),
                              s->filename, seg->segment_idx) < 0) {
        av_log(oc, AV_LOG_ERROR, "Invalid segment filename template '%s'\n", s->filename);
        return AVERROR(EINVAL);
    }
    av_strlcpy(seg->cur_entry.filename, oc->filename, sizeof(seg->cur_entry.filename));
    return 0;
}

static int segment_start(AVFormatContext *s, int write_header)
{
    SegmentContext *seg = s->priv_data;
    AVFormatContext *oc = seg->avf;
    int err = 0;

    if (write_header) {
        avformat_free_context(oc);
        seg->avf = NULL;
        if ((err = segment_mux_init(s)) < 0)
            return err;
        oc = seg->avf;
    }

    seg->segment_idx++;
    if ((err = set_segment_filename(s)) < 0)
        return err;
    seg->segment_count++;

    if ((err = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
                          &s->interrupt_callback, NULL)) < 0)
        return err;

    if (oc->oformat->priv_class && oc->priv_data)
        av_opt_set(oc->priv_data, "resend_headers", "1", 0); /* mpegts specific */

    if (write_header) {
        if ((err = avformat_write_header(oc, NULL)) < 0)
            return err;
    }

    seg->is_first_pkt = 1;
    return 0;
}

static int segment_list_open(AVFormatContext *s)
{
    SegmentContext *seg = s->priv_data;
    int ret;

    ret = avio_open2(&seg->list_pb, seg->list, AVIO_FLAG_WRITE,
                     &s->interrupt_callback, NULL);
    if (ret < 0)
        return ret;

    if (seg->list_type == LIST_TYPE_M3U8 && seg->segment_list_entries) {
        SegmentListEntry *entry;
        double max_duration = 0;

        avio_printf(seg->list_pb, "#EXTM3U\n");
        avio_printf(seg->list_pb, "#EXT-X-VERSION:3\n");
        avio_printf(seg->list_pb, "#EXT-X-MEDIA-SEQUENCE:%d\n", seg->segment_list_entries->index);
        avio_printf(seg->list_pb, "#EXT-X-ALLOW-CACHE:%s\n",
                    seg->list_flags & SEGMENT_LIST_FLAG_CACHE ? "YES" : "NO");

        for (entry = seg->segment_list_entries; entry; entry = entry->next)
            max_duration = FFMAX(max_duration, entry->end_time - entry->start_time);
        avio_printf(seg->list_pb, "#EXT-X-TARGETDURATION:%"PRId64"\n", (int64_t)ceil(max_duration));
    }

    return ret;
}

static void segment_list_print_entry(AVIOContext      *list_ioctx,
                                     ListType          list_type,
                                     const SegmentListEntry *list_entry)
{
    switch (list_type) {
    case LIST_TYPE_FLAT:
        avio_printf(list_ioctx, "%s\n", list_entry->filename);
        break;
    case LIST_TYPE_CSV:
    case LIST_TYPE_EXT:
        print_csv_escaped_str(list_ioctx, list_entry->filename);
        avio_printf(list_ioctx, ",%f,%f\n", list_entry->start_time, list_entry->end_time);
        break;
    case LIST_TYPE_M3U8:
        avio_printf(list_ioctx, "#EXTINF:%f,\n%s\n",
                    list_entry->end_time - list_entry->start_time, list_entry->filename);
        break;
    default:
        av_assert0(!"Invalid list type");
    }
}

static int segment_end(AVFormatContext *s, int write_trailer, int is_last)
{
    SegmentContext *seg = s->priv_data;
    AVFormatContext *oc = seg->avf;
    int ret = 0;

    av_write_frame(oc, NULL); /* Flush any buffered data (fragmented mp4) */
    if (write_trailer)
        ret = av_write_trailer(oc);

    if (ret < 0)
        av_log(s, AV_LOG_ERROR, "Failure occurred when ending segment '%s'\n",
               oc->filename);

    if (seg->list) {
        if (seg->list_size || seg->list_type == LIST_TYPE_M3U8) {
            SegmentListEntry *entry = av_mallocz(sizeof(*entry));
            if (!entry) {
                ret = AVERROR(ENOMEM);
                goto end;
            }

            /* append new element */
            memcpy(entry, &seg->cur_entry, sizeof(*entry));
            if (!seg->segment_list_entries)
                seg->segment_list_entries = seg->segment_list_entries_end = entry;
            else
                seg->segment_list_entries_end->next = entry;
            seg->segment_list_entries_end = entry;

            /* drop first item */
            if (seg->list_size && seg->segment_count > seg->list_size) {
                entry = seg->segment_list_entries;
                seg->segment_list_entries = seg->segment_list_entries->next;
                av_freep(&entry);
            }

            avio_close(seg->list_pb);
            if ((ret = segment_list_open(s)) < 0)
                goto end;
            for (entry = seg->segment_list_entries; entry; entry = entry->next)
                segment_list_print_entry(seg->list_pb, seg->list_type, entry);
            if (seg->list_type == LIST_TYPE_M3U8 && is_last)
                avio_printf(seg->list_pb, "#EXT-X-ENDLIST\n");
        } else {
            segment_list_print_entry(seg->list_pb, seg->list_type, &seg->cur_entry);
        }
        avio_flush(seg->list_pb);
    }

end:
    avio_close(oc->pb);

    return ret;
}

static int parse_times(void *log_ctx, int64_t **times, int *nb_times,
                       const char *times_str)
{
    char *p;
    int i, ret = 0;
    char *times_str1 = av_strdup(times_str);
    char *saveptr = NULL;

    if (!times_str1)
        return AVERROR(ENOMEM);

#define FAIL(err) ret = err; goto end

    *nb_times = 1;
    for (p = times_str1; *p; p++)
        if (*p == ',')
            (*nb_times)++;

    *times = av_malloc(sizeof(**times) * *nb_times);
    if (!*times) {
        av_log(log_ctx, AV_LOG_ERROR, "Could not allocate forced times array\n");
        FAIL(AVERROR(ENOMEM));
    }

    p = times_str1;
    for (i = 0; i < *nb_times; i++) {
        int64_t t;
        char *tstr = av_strtok(p, ",", &saveptr);
        p = NULL;

        if (!tstr || !tstr[0]) {
            av_log(log_ctx, AV_LOG_ERROR, "Empty time specification in times list %s\n",
                   times_str);
            FAIL(AVERROR(EINVAL));
        }

        ret = av_parse_time(&t, tstr, 1);
        if (ret < 0) {
            av_log(log_ctx, AV_LOG_ERROR,
                   "Invalid time duration specification '%s' in times list %s\n", tstr, times_str);
            FAIL(AVERROR(EINVAL));
        }
        (*times)[i] = t;

        /* check on monotonicity */
        if (i && (*times)[i-1] > (*times)[i]) {
            av_log(log_ctx, AV_LOG_ERROR,
                   "Specified time %f is greater than the following time %f\n",
                   (float)((*times)[i])/1000000, (float)((*times)[i-1])/1000000);
            FAIL(AVERROR(EINVAL));
        }
    }

end:
    av_free(times_str1);
    return ret;
}

static int parse_frames(void *log_ctx, int **frames, int *nb_frames,
                        const char *frames_str)
{
    char *p;
    int i, ret = 0;
    char *frames_str1 = av_strdup(frames_str);
    char *saveptr = NULL;

    if (!frames_str1)
        return AVERROR(ENOMEM);

#define FAIL(err) ret = err; goto end

    *nb_frames = 1;
    for (p = frames_str1; *p; p++)
        if (*p == ',')
            (*nb_frames)++;

    *frames = av_malloc(sizeof(**frames) * *nb_frames);
    if (!*frames) {
        av_log(log_ctx, AV_LOG_ERROR, "Could not allocate forced frames array\n");
        FAIL(AVERROR(ENOMEM));
    }

    p = frames_str1;
    for (i = 0; i < *nb_frames; i++) {
        long int f;
        char *tailptr;
        char *fstr = av_strtok(p, ",", &saveptr);

        p = NULL;
        if (!fstr) {
            av_log(log_ctx, AV_LOG_ERROR, "Empty frame specification in frame list %s\n",
                   frames_str);
            FAIL(AVERROR(EINVAL));
        }
        f = strtol(fstr, &tailptr, 10);
        if (*tailptr || f <= 0 || f >= INT_MAX) {
            av_log(log_ctx, AV_LOG_ERROR,
                   "Invalid argument '%s', must be a positive integer <= INT64_MAX\n",
                   fstr);
            FAIL(AVERROR(EINVAL));
        }
        (*frames)[i] = f;

        /* check on monotonicity */
        if (i && (*frames)[i-1] > (*frames)[i]) {
            av_log(log_ctx, AV_LOG_ERROR,
                   "Specified frame %d is greater than the following frame %d\n",
                   (*frames)[i], (*frames)[i-1]);
            FAIL(AVERROR(EINVAL));
        }
    }

end:
    av_free(frames_str1);
    return ret;
}

static int open_null_ctx(AVIOContext **ctx)
{
    int buf_size = 32768;
    uint8_t *buf = av_malloc(buf_size);
    if (!buf)
        return AVERROR(ENOMEM);
    *ctx = avio_alloc_context(buf, buf_size, AVIO_FLAG_WRITE, NULL, NULL, NULL, NULL);
    if (!*ctx) {
        av_free(buf);
        return AVERROR(ENOMEM);
    }
    return 0;
}

static void close_null_ctx(AVIOContext *pb)
{
    av_free(pb->buffer);
    av_free(pb);
}

static int select_reference_stream(AVFormatContext *s)
{
    SegmentContext *seg = s->priv_data;
    int ret, i;

    seg->reference_stream_index = -1;
    if (!strcmp(seg->reference_stream_specifier, "auto")) {
        /* select first index of type with highest priority */
        int type_index_map[AVMEDIA_TYPE_NB];
        static const enum AVMediaType type_priority_list[] = {
            AVMEDIA_TYPE_VIDEO,
            AVMEDIA_TYPE_AUDIO,
            AVMEDIA_TYPE_SUBTITLE,
            AVMEDIA_TYPE_DATA,
            AVMEDIA_TYPE_ATTACHMENT
        };
        enum AVMediaType type;

        for (i = 0; i < AVMEDIA_TYPE_NB; i++)
            type_index_map[i] = -1;

        /* select first index for each type */
        for (i = 0; i < s->nb_streams; i++) {
            type = s->streams[i]->codec->codec_type;
            if ((unsigned)type < AVMEDIA_TYPE_NB && type_index_map[type] == -1
                /* ignore attached pictures/cover art streams */
                && !(s->streams[i]->disposition & AV_DISPOSITION_ATTACHED_PIC))
                type_index_map[type] = i;
        }

        for (i = 0; i < FF_ARRAY_ELEMS(type_priority_list); i++) {
            type = type_priority_list[i];
            if ((seg->reference_stream_index = type_index_map[type]) >= 0)
                break;
        }
    } else {
        for (i = 0; i < s->nb_streams; i++) {
            ret = avformat_match_stream_specifier(s, s->streams[i],
                                                  seg->reference_stream_specifier);
            if (ret < 0)
                return ret;
            if (ret > 0) {
                seg->reference_stream_index = i;
                break;
            }
        }
    }

    if (seg->reference_stream_index < 0) {
        av_log(s, AV_LOG_ERROR, "Could not select stream matching identifier '%s'\n",
               seg->reference_stream_specifier);
        return AVERROR(EINVAL);
    }

    return 0;
}

static int seg_write_header(AVFormatContext *s)
{
    SegmentContext *seg = s->priv_data;
    AVFormatContext *oc = NULL;
    int ret;

    seg->segment_count = 0;
    if (!seg->write_header_trailer)
        seg->individual_header_trailer = 0;

    if (!!seg->time_str + !!seg->times_str + !!seg->frames_str > 1) {
        av_log(s, AV_LOG_ERROR,
               "segment_time, segment_times, and segment_frames options "
               "are mutually exclusive, select just one of them\n");
        return AVERROR(EINVAL);
    }

    if (seg->times_str) {
        if ((ret = parse_times(s, &seg->times, &seg->nb_times, seg->times_str)) < 0)
            return ret;
    } else if (seg->frames_str) {
        if ((ret = parse_frames(s, &seg->frames, &seg->nb_frames, seg->frames_str)) < 0)
            return ret;
    } else {
        /* set default value if not specified */
        if (!seg->time_str)
            seg->time_str = av_strdup("2");
        if ((ret = av_parse_time(&seg->time, seg->time_str, 1)) < 0) {
            av_log(s, AV_LOG_ERROR,
                   "Invalid time duration specification '%s' for segment_time option\n",
                   seg->time_str);
            return ret;
        }
    }

    if (seg->time_delta_str) {
        if ((ret = av_parse_time(&seg->time_delta, seg->time_delta_str, 1)) < 0) {
            av_log(s, AV_LOG_ERROR,
                   "Invalid time duration specification '%s' for delta option\n",
                   seg->time_delta_str);
            return ret;
        }
    }

    if (seg->list) {
        if (seg->list_type == LIST_TYPE_UNDEFINED) {
            if      (av_match_ext(seg->list, "csv" )) seg->list_type = LIST_TYPE_CSV;
            else if (av_match_ext(seg->list, "ext" )) seg->list_type = LIST_TYPE_EXT;
            else if (av_match_ext(seg->list, "m3u8")) seg->list_type = LIST_TYPE_M3U8;
            else                                      seg->list_type = LIST_TYPE_FLAT;
        }
        if ((ret = segment_list_open(s)) < 0)
            goto fail;
    }
    if (seg->list_type == LIST_TYPE_EXT)
        av_log(s, AV_LOG_WARNING, "'ext' list type option is deprecated in favor of 'csv'\n");

    if ((ret = select_reference_stream(s)) < 0)
        goto fail;
    av_log(s, AV_LOG_VERBOSE, "Selected stream id:%d type:%s\n",
           seg->reference_stream_index,
           av_get_media_type_string(s->streams[seg->reference_stream_index]->codec->codec_type));

    seg->oformat = av_guess_format(seg->format, s->filename, NULL);

    if (!seg->oformat) {
        ret = AVERROR_MUXER_NOT_FOUND;
        goto fail;
    }
    if (seg->oformat->flags & AVFMT_NOFILE) {
        av_log(s, AV_LOG_ERROR, "format %s not supported.\n",
               seg->oformat->name);
        ret = AVERROR(EINVAL);
        goto fail;
    }

    if ((ret = segment_mux_init(s)) < 0)
        goto fail;
    oc = seg->avf;

    if ((ret = set_segment_filename(s)) < 0)
        goto fail;
    seg->segment_count++;

    if (seg->write_header_trailer) {
        if ((ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
                              &s->interrupt_callback, NULL)) < 0)
            goto fail;
    } else {
        if ((ret = open_null_ctx(&oc->pb)) < 0)
            goto fail;
    }

    if ((ret = avformat_write_header(oc, NULL)) < 0) {
        avio_close(oc->pb);
        goto fail;
    }
    seg->is_first_pkt = 1;

    if (oc->avoid_negative_ts > 0 && s->avoid_negative_ts < 0)
        s->avoid_negative_ts = 1;

    if (!seg->write_header_trailer) {
        close_null_ctx(oc->pb);
        if ((ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
                              &s->interrupt_callback, NULL)) < 0)
            goto fail;
    }

fail:
    if (ret) {
        if (seg->list)
            avio_close(seg->list_pb);
        if (seg->avf)
            avformat_free_context(seg->avf);
    }
    return ret;
}

static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
{
    SegmentContext *seg = s->priv_data;
    AVFormatContext *oc = seg->avf;
    AVStream *st = s->streams[pkt->stream_index];
    int64_t end_pts = INT64_MAX;
    int start_frame = INT_MAX;
    int ret;

    if (seg->times) {
        end_pts = seg->segment_count <= seg->nb_times ?
            seg->times[seg->segment_count-1] : INT64_MAX;
    } else if (seg->frames) {
        start_frame = seg->segment_count <= seg->nb_frames ?
            seg->frames[seg->segment_count-1] : INT_MAX;
    } else {
        end_pts = seg->time * seg->segment_count;
    }

    av_dlog(s, "packet stream:%d pts:%s pts_time:%s is_key:%d frame:%d\n",
           pkt->stream_index, av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base),
           pkt->flags & AV_PKT_FLAG_KEY,
           pkt->stream_index == seg->reference_stream_index ? seg->frame_count : -1);

    if (pkt->stream_index == seg->reference_stream_index &&
        pkt->flags & AV_PKT_FLAG_KEY &&
        (seg->frame_count >= start_frame ||
         (pkt->pts != AV_NOPTS_VALUE &&
          av_compare_ts(pkt->pts, st->time_base,
                        end_pts-seg->time_delta, AV_TIME_BASE_Q) >= 0))) {
        ret = segment_end(s, seg->individual_header_trailer, 0);

        if (!ret)
            ret = segment_start(s, seg->individual_header_trailer);

        if (ret)
            goto fail;

        oc = seg->avf;

        seg->cur_entry.index = seg->segment_idx;
        seg->cur_entry.start_time = (double)pkt->pts * av_q2d(st->time_base);
        seg->cur_entry.start_pts = av_rescale_q(pkt->pts, st->time_base, AV_TIME_BASE_Q);
    } else if (pkt->pts != AV_NOPTS_VALUE) {
        seg->cur_entry.end_time =
            FFMAX(seg->cur_entry.end_time, (double)(pkt->pts + pkt->duration) * av_q2d(st->time_base));
    }

    if (seg->is_first_pkt) {
        av_log(s, AV_LOG_DEBUG, "segment:'%s' starts with packet stream:%d pts:%s pts_time:%s frame:%d\n",
               seg->avf->filename, pkt->stream_index,
               av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base), seg->frame_count);
        seg->is_first_pkt = 0;
    }

    if (seg->reset_timestamps) {
        av_log(s, AV_LOG_DEBUG, "stream:%d start_pts_time:%s pts:%s pts_time:%s dts:%s dts_time:%s",
               pkt->stream_index,
               av_ts2timestr(seg->cur_entry.start_pts, &AV_TIME_BASE_Q),
               av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base),
               av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &st->time_base));

        /* compute new timestamps */
        if (pkt->pts != AV_NOPTS_VALUE)
            pkt->pts -= av_rescale_q(seg->cur_entry.start_pts, AV_TIME_BASE_Q, st->time_base);
        if (pkt->dts != AV_NOPTS_VALUE)
            pkt->dts -= av_rescale_q(seg->cur_entry.start_pts, AV_TIME_BASE_Q, st->time_base);

        av_log(s, AV_LOG_DEBUG, " -> pts:%s pts_time:%s dts:%s dts_time:%s\n",
               av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base),
               av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &st->time_base));
    }

    ret = ff_write_chained(oc, pkt->stream_index, pkt, s);

fail:
    if (pkt->stream_index == seg->reference_stream_index)
        seg->frame_count++;

    if (ret < 0) {
        if (seg->list)
            avio_close(seg->list_pb);
        avformat_free_context(oc);
    }

    return ret;
}

static int seg_write_trailer(struct AVFormatContext *s)
{
    SegmentContext *seg = s->priv_data;
    AVFormatContext *oc = seg->avf;
    SegmentListEntry *cur, *next;

    int ret;
    if (!seg->write_header_trailer) {
        if ((ret = segment_end(s, 0, 1)) < 0)
            goto fail;
        open_null_ctx(&oc->pb);
        ret = av_write_trailer(oc);
        close_null_ctx(oc->pb);
    } else {
        ret = segment_end(s, 1, 1);
    }
fail:
    if (seg->list)
        avio_close(seg->list_pb);

    av_opt_free(seg);
    av_freep(&seg->times);
    av_freep(&seg->frames);

    cur = seg->segment_list_entries;
    while (cur) {
        next = cur->next;
        av_free(cur);
        cur = next;
    }

    avformat_free_context(oc);
    return ret;
}

#define OFFSET(x) offsetof(SegmentContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
    { "reference_stream",  "set reference stream", OFFSET(reference_stream_specifier), AV_OPT_TYPE_STRING, {.str = "auto"}, CHAR_MIN, CHAR_MAX, E },
    { "segment_format",    "set container format used for the segments", OFFSET(format),  AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },
    { "segment_list",      "set the segment list filename",              OFFSET(list),    AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },

    { "segment_list_flags","set flags affecting segment list generation", OFFSET(list_flags), AV_OPT_TYPE_FLAGS, {.i64 = SEGMENT_LIST_FLAG_CACHE }, 0, UINT_MAX, E, "list_flags"},
    { "cache",             "allow list caching",                                    0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_LIST_FLAG_CACHE }, INT_MIN, INT_MAX,   E, "list_flags"},
    { "live",              "enable live-friendly list generation (useful for HLS)", 0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_LIST_FLAG_LIVE }, INT_MIN, INT_MAX,    E, "list_flags"},

    { "segment_list_size", "set the maximum number of playlist entries", OFFSET(list_size), AV_OPT_TYPE_INT,  {.i64 = 0},     0, INT_MAX, E },

    { "segment_list_type", "set the segment list type",                  OFFSET(list_type), AV_OPT_TYPE_INT,  {.i64 = LIST_TYPE_UNDEFINED}, -1, LIST_TYPE_NB-1, E, "list_type" },
    { "flat", "flat format",     0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_FLAT }, INT_MIN, INT_MAX, E, "list_type" },
    { "csv",  "csv format",      0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_CSV  }, INT_MIN, INT_MAX, E, "list_type" },
    { "ext",  "extended format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_EXT  }, INT_MIN, INT_MAX, E, "list_type" },
    { "m3u8", "M3U8 format",     0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, E, "list_type" },
    { "hls", "Apple HTTP Live Streaming compatible", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, E, "list_type" },

    { "segment_time",      "set segment duration",                       OFFSET(time_str),AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       E },
    { "segment_time_delta","set approximation value used for the segment times", OFFSET(time_delta_str), AV_OPT_TYPE_STRING, {.str = "0"}, 0, 0, E },
    { "segment_times",     "set segment split time points",              OFFSET(times_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
    { "segment_frames",    "set segment split frame numbers",            OFFSET(frames_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
    { "segment_wrap",      "set number after which the index wraps",     OFFSET(segment_idx_wrap), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
    { "segment_start_number", "set the sequence number of the first segment", OFFSET(segment_idx), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },

    { "individual_header_trailer", "write header/trailer to each segment", OFFSET(individual_header_trailer), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, E },
    { "write_header_trailer", "write a header to the first segment and a trailer to the last one", OFFSET(write_header_trailer), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, E },
    { "reset_timestamps", "reset timestamps at the begin of each segment", OFFSET(reset_timestamps), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, E },
    { NULL },
};

static const AVClass seg_class = {
    .class_name = "segment muxer",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVOutputFormat ff_segment_muxer = {
    .name           = "segment",
    .long_name      = NULL_IF_CONFIG_SMALL("segment"),
    .priv_data_size = sizeof(SegmentContext),
    .flags          = AVFMT_NOFILE|AVFMT_GLOBALHEADER,
    .write_header   = seg_write_header,
    .write_packet   = seg_write_packet,
    .write_trailer  = seg_write_trailer,
    .priv_class     = &seg_class,
};

static const AVClass sseg_class = {
    .class_name = "stream_segment muxer",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVOutputFormat ff_stream_segment_muxer = {
    .name           = "stream_segment,ssegment",
    .long_name      = NULL_IF_CONFIG_SMALL("streaming segment muxer"),
    .priv_data_size = sizeof(SegmentContext),
    .flags          = AVFMT_NOFILE,
    .write_header   = seg_write_header,
    .write_packet   = seg_write_packet,
    .write_trailer  = seg_write_trailer,
    .priv_class     = &sseg_class,
};