aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/flvdec.c
blob: eb31a6e1e2b2364add6ef4c5446464645955fe09 (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
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
/*
 * FLV demuxer
 * Copyright (c) 2003 The Libav Project
 *
 * This demuxer will generate a 1 byte extradata for VP6F content.
 * It is composed of:
 *  - upper 4bits: difference between encoded width and visible width
 *  - lower 4bits: difference between encoded height and visible height
 *
 * 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
 */

#include "libavutil/avstring.h"
#include "libavutil/channel_layout.h"
#include "libavutil/dict.h"
#include "libavutil/opt.h"
#include "libavutil/intfloat.h"
#include "libavutil/mathematics.h"
#include "libavcodec/bytestream.h"
#include "libavcodec/mpeg4audio.h"
#include "avformat.h"
#include "internal.h"
#include "avio_internal.h"
#include "flv.h"

#define KEYFRAMES_TAG            "keyframes"
#define KEYFRAMES_TIMESTAMP_TAG  "times"
#define KEYFRAMES_BYTEOFFSET_TAG "filepositions"

#define VALIDATE_INDEX_TS_THRESH 2500

typedef struct FLVContext {
    const AVClass *class; ///< Class for private options.
    int trust_metadata;   ///< configure streams according onMetaData
    int wrong_dts;        ///< wrong dts due to negative cts
    uint8_t *new_extradata[2];
    int new_extradata_size[2];
    int last_sample_rate;
    int last_channels;
    struct {
        int64_t dts;
        int64_t pos;
    } validate_index[2];
    int validate_next;
    int validate_count;
} FLVContext;

static int flv_probe(AVProbeData *p)
{
    const uint8_t *d;

    d = p->buf;
    if (d[0] == 'F' &&
        d[1] == 'L' &&
        d[2] == 'V' &&
        d[3] < 5 && d[5] == 0 &&
        AV_RB32(d + 5) > 8) {
        return AVPROBE_SCORE_MAX;
    }
    return 0;
}

static AVStream *create_stream(AVFormatContext *s, int codec_type)
{
    AVStream *st = avformat_new_stream(s, NULL);
    if (!st)
        return NULL;
    st->codec->codec_type = codec_type;
    avpriv_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
    return st;
}

static int flv_same_audio_codec(AVCodecContext *acodec, int flags)
{
    int bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
    int flv_codecid           = flags & FLV_AUDIO_CODECID_MASK;
    int codec_id;

    if (!acodec->codec_id && !acodec->codec_tag)
        return 1;

    if (acodec->bits_per_coded_sample != bits_per_coded_sample)
        return 0;

    switch (flv_codecid) {
    // no distinction between S16 and S8 PCM codec flags
    case FLV_CODECID_PCM:
        codec_id = bits_per_coded_sample == 8
                   ? AV_CODEC_ID_PCM_U8
#if HAVE_BIGENDIAN
                   : AV_CODEC_ID_PCM_S16BE;
#else
                   : AV_CODEC_ID_PCM_S16LE;
#endif
        return codec_id == acodec->codec_id;
    case FLV_CODECID_PCM_LE:
        codec_id = bits_per_coded_sample == 8
                   ? AV_CODEC_ID_PCM_U8
                   : AV_CODEC_ID_PCM_S16LE;
        return codec_id == acodec->codec_id;
    case FLV_CODECID_AAC:
        return acodec->codec_id == AV_CODEC_ID_AAC;
    case FLV_CODECID_ADPCM:
        return acodec->codec_id == AV_CODEC_ID_ADPCM_SWF;
    case FLV_CODECID_SPEEX:
        return acodec->codec_id == AV_CODEC_ID_SPEEX;
    case FLV_CODECID_MP3:
        return acodec->codec_id == AV_CODEC_ID_MP3;
    case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
    case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
    case FLV_CODECID_NELLYMOSER:
        return acodec->codec_id == AV_CODEC_ID_NELLYMOSER;
    case FLV_CODECID_PCM_MULAW:
        return acodec->sample_rate == 8000 &&
               acodec->codec_id    == AV_CODEC_ID_PCM_MULAW;
    case FLV_CODECID_PCM_ALAW:
        return acodec->sample_rate == 8000 &&
               acodec->codec_id    == AV_CODEC_ID_PCM_ALAW;
    default:
        return acodec->codec_tag == (flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
    }
}

static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream,
                                AVCodecContext *acodec, int flv_codecid)
{
    switch (flv_codecid) {
    // no distinction between S16 and S8 PCM codec flags
    case FLV_CODECID_PCM:
        acodec->codec_id = acodec->bits_per_coded_sample == 8
                           ? AV_CODEC_ID_PCM_U8
#if HAVE_BIGENDIAN
                           : AV_CODEC_ID_PCM_S16BE;
#else
                           : AV_CODEC_ID_PCM_S16LE;
#endif
        break;
    case FLV_CODECID_PCM_LE:
        acodec->codec_id = acodec->bits_per_coded_sample == 8
                           ? AV_CODEC_ID_PCM_U8
                           : AV_CODEC_ID_PCM_S16LE;
        break;
    case FLV_CODECID_AAC:
        acodec->codec_id = AV_CODEC_ID_AAC;
        break;
    case FLV_CODECID_ADPCM:
        acodec->codec_id = AV_CODEC_ID_ADPCM_SWF;
        break;
    case FLV_CODECID_SPEEX:
        acodec->codec_id    = AV_CODEC_ID_SPEEX;
        acodec->sample_rate = 16000;
        break;
    case FLV_CODECID_MP3:
        acodec->codec_id      = AV_CODEC_ID_MP3;
        astream->need_parsing = AVSTREAM_PARSE_FULL;
        break;
    case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
        // in case metadata does not otherwise declare samplerate
        acodec->sample_rate = 8000;
        acodec->codec_id    = AV_CODEC_ID_NELLYMOSER;
        break;
    case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
        acodec->sample_rate = 16000;
        acodec->codec_id    = AV_CODEC_ID_NELLYMOSER;
        break;
    case FLV_CODECID_NELLYMOSER:
        acodec->codec_id = AV_CODEC_ID_NELLYMOSER;
        break;
    case FLV_CODECID_PCM_MULAW:
        acodec->sample_rate = 8000;
        acodec->codec_id    = AV_CODEC_ID_PCM_MULAW;
        break;
    case FLV_CODECID_PCM_ALAW:
        acodec->sample_rate = 8000;
        acodec->codec_id    = AV_CODEC_ID_PCM_ALAW;
        break;
    default:
        av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n",
               flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
        acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
    }
}

static int flv_same_video_codec(AVCodecContext *vcodec, int flags)
{
    int flv_codecid = flags & FLV_VIDEO_CODECID_MASK;

    if (!vcodec->codec_id && !vcodec->codec_tag)
        return 1;

    switch (flv_codecid) {
    case FLV_CODECID_H263:
        return vcodec->codec_id == AV_CODEC_ID_FLV1;
    case FLV_CODECID_SCREEN:
        return vcodec->codec_id == AV_CODEC_ID_FLASHSV;
    case FLV_CODECID_SCREEN2:
        return vcodec->codec_id == AV_CODEC_ID_FLASHSV2;
    case FLV_CODECID_VP6:
        return vcodec->codec_id == AV_CODEC_ID_VP6F;
    case FLV_CODECID_VP6A:
        return vcodec->codec_id == AV_CODEC_ID_VP6A;
    case FLV_CODECID_H264:
        return vcodec->codec_id == AV_CODEC_ID_H264;
    default:
        return vcodec->codec_tag == flv_codecid;
    }
}

static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream,
                               int flv_codecid, int read)
{
    AVCodecContext *vcodec = vstream->codec;
    switch (flv_codecid) {
    case FLV_CODECID_H263:
        vcodec->codec_id = AV_CODEC_ID_FLV1;
        break;
    case FLV_CODECID_SCREEN:
        vcodec->codec_id = AV_CODEC_ID_FLASHSV;
        break;
    case FLV_CODECID_SCREEN2:
        vcodec->codec_id = AV_CODEC_ID_FLASHSV2;
        break;
    case FLV_CODECID_VP6:
        vcodec->codec_id = AV_CODEC_ID_VP6F;
    case FLV_CODECID_VP6A:
        if (flv_codecid == FLV_CODECID_VP6A)
            vcodec->codec_id = AV_CODEC_ID_VP6A;
        if (read) {
            if (vcodec->extradata_size != 1) {
                vcodec->extradata = av_malloc(1);
                if (vcodec->extradata)
                    vcodec->extradata_size = 1;
            }
            if (vcodec->extradata)
                vcodec->extradata[0] = avio_r8(s->pb);
            else
                avio_skip(s->pb, 1);
        }
        return 1;     // 1 byte body size adjustment for flv_read_packet()
    case FLV_CODECID_H264:
        vcodec->codec_id = AV_CODEC_ID_H264;
        return 3;     // not 4, reading packet type will consume one byte
    default:
        av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
        vcodec->codec_tag = flv_codecid;
    }

    return 0;
}

static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize)
{
    int length = avio_rb16(ioc);
    if (length >= buffsize) {
        avio_skip(ioc, length);
        return -1;
    }

    avio_read(ioc, buffer, length);

    buffer[length] = '\0';

    return length;
}

static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc,
                                 AVStream *vstream, int64_t max_pos)
{
    FLVContext *flv       = s->priv_data;
    unsigned int arraylen = 0, timeslen = 0, fileposlen = 0, i;
    double num_val;
    char str_val[256];
    int64_t *times         = NULL;
    int64_t *filepositions = NULL;
    int ret                = AVERROR(ENOSYS);
    int64_t initial_pos    = avio_tell(ioc);

    if (s->flags & AVFMT_FLAG_IGNIDX)
        return 0;

    while (avio_tell(ioc) < max_pos - 2 &&
           amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
        int64_t *current_array;

        // Expect array object in context
        if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
            break;

        arraylen = avio_rb32(ioc);
        if (arraylen >> 28)
            break;

        /* Expect only 'times' or 'filepositions' sub-arrays in other
         * case refuse to use such metadata for indexing. */
        if (!strcmp(KEYFRAMES_TIMESTAMP_TAG, str_val) && !times) {
            if (!(times = av_mallocz(sizeof(*times) * arraylen))) {
                ret = AVERROR(ENOMEM);
                goto finish;
            }
            timeslen      = arraylen;
            current_array = times;
        } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) &&
                   !filepositions) {
            if (!(filepositions = av_mallocz(sizeof(*filepositions) * arraylen))) {
                ret = AVERROR(ENOMEM);
                goto finish;
            }
            fileposlen    = arraylen;
            current_array = filepositions;
        } else
            // unexpected metatag inside keyframes, will not use such
            // metadata for indexing
            break;

        for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
            if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
                goto finish;
            num_val          = av_int2double(avio_rb64(ioc));
            current_array[i] = num_val;
        }
        if (times && filepositions) {
            // All done, exiting at a position allowing amf_parse_object
            // to finish parsing the object
            ret = 0;
            break;
        }
    }

    if (!ret && timeslen == fileposlen) {
        for (i = 0; i < fileposlen; i++) {
            av_add_index_entry(vstream, filepositions[i], times[i] * 1000,
                               0, 0, AVINDEX_KEYFRAME);
            if (i < 2) {
                flv->validate_index[i].pos = filepositions[i];
                flv->validate_index[i].dts = times[i] * 1000;
                flv->validate_count        = i + 1;
            }
        }
    } else
        av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");

finish:
    av_freep(&times);
    av_freep(&filepositions);
    // If we got unexpected data, but successfully reset back to
    // the start pos, the caller can continue parsing
    if (ret < 0 && avio_seek(ioc, initial_pos, SEEK_SET) > 0)
        return 0;
    return ret;
}

static int amf_parse_object(AVFormatContext *s, AVStream *astream,
                            AVStream *vstream, const char *key,
                            int64_t max_pos, int depth)
{
    AVCodecContext *acodec, *vcodec;
    FLVContext *flv = s->priv_data;
    AVIOContext *ioc;
    AMFDataType amf_type;
    char str_val[256];
    double num_val;

    num_val  = 0;
    ioc      = s->pb;
    amf_type = avio_r8(ioc);

    switch (amf_type) {
    case AMF_DATA_TYPE_NUMBER:
        num_val = av_int2double(avio_rb64(ioc));
        break;
    case AMF_DATA_TYPE_BOOL:
        num_val = avio_r8(ioc);
        break;
    case AMF_DATA_TYPE_STRING:
        if (amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
            return -1;
        break;
    case AMF_DATA_TYPE_OBJECT:
        if ((vstream || astream) && key &&
            !strcmp(KEYFRAMES_TAG, key) && depth == 1)
            if (parse_keyframes_index(s, ioc, vstream ? vstream : astream,
                                      max_pos) < 0)
                return -1;

        while (avio_tell(ioc) < max_pos - 2 &&
               amf_get_string(ioc, str_val, sizeof(str_val)) > 0)
            if (amf_parse_object(s, astream, vstream, str_val, max_pos,
                                 depth + 1) < 0)
                return -1;     // if we couldn't skip, bomb out.
        if (avio_r8(ioc) != AMF_END_OF_OBJECT)
            return -1;
        break;
    case AMF_DATA_TYPE_NULL:
    case AMF_DATA_TYPE_UNDEFINED:
    case AMF_DATA_TYPE_UNSUPPORTED:
        break;     // these take up no additional space
    case AMF_DATA_TYPE_MIXEDARRAY:
        avio_skip(ioc, 4);     // skip 32-bit max array index
        while (avio_tell(ioc) < max_pos - 2 &&
               amf_get_string(ioc, str_val, sizeof(str_val)) > 0)
            // this is the only case in which we would want a nested
            // parse to not skip over the object
            if (amf_parse_object(s, astream, vstream, str_val, max_pos,
                                 depth + 1) < 0)
                return -1;
        if (avio_r8(ioc) != AMF_END_OF_OBJECT)
            return -1;
        break;
    case AMF_DATA_TYPE_ARRAY:
    {
        unsigned int arraylen, i;

        arraylen = avio_rb32(ioc);
        for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++)
            if (amf_parse_object(s, NULL, NULL, NULL, max_pos,
                                 depth + 1) < 0)
                return -1;      // if we couldn't skip, bomb out.
    }
    break;
    case AMF_DATA_TYPE_DATE:
        avio_skip(ioc, 8 + 2);  // timestamp (double) and UTC offset (int16)
        break;
    default:                    // unsupported type, we couldn't skip
        return -1;
    }

    if (key) {
        // stream info doesn't live any deeper than the first object
        if (depth == 1) {
            acodec = astream ? astream->codec : NULL;
            vcodec = vstream ? vstream->codec : NULL;

            if (amf_type == AMF_DATA_TYPE_NUMBER ||
                amf_type == AMF_DATA_TYPE_BOOL) {
                if (!strcmp(key, "duration"))
                    s->duration = num_val * AV_TIME_BASE;
                else if (!strcmp(key, "videodatarate") && vcodec &&
                         0 <= (int)(num_val * 1024.0))
                    vcodec->bit_rate = num_val * 1024.0;
                else if (!strcmp(key, "audiodatarate") && acodec &&
                         0 <= (int)(num_val * 1024.0))
                    acodec->bit_rate = num_val * 1024.0;
                else if (!strcmp(key, "datastream")) {
                    AVStream *st = create_stream(s, AVMEDIA_TYPE_DATA);
                    if (!st)
                        return AVERROR(ENOMEM);
                    st->codec->codec_id = AV_CODEC_ID_TEXT;
                } else if (flv->trust_metadata) {
                    if (!strcmp(key, "videocodecid") && vcodec) {
                        flv_set_video_codec(s, vstream, num_val, 0);
                    } else if (!strcmp(key, "audiocodecid") && acodec) {
                        int id = ((int)num_val) << FLV_AUDIO_CODECID_OFFSET;
                        flv_set_audio_codec(s, astream, acodec, id);
                    } else if (!strcmp(key, "audiosamplerate") && acodec) {
                        acodec->sample_rate = num_val;
                    } else if (!strcmp(key, "audiosamplesize") && acodec) {
                        acodec->bits_per_coded_sample = num_val;
                    } else if (!strcmp(key, "stereo") && acodec) {
                        acodec->channels       = num_val + 1;
                        acodec->channel_layout = acodec->channels == 2 ?
                                                 AV_CH_LAYOUT_STEREO :
                                                 AV_CH_LAYOUT_MONO;
                    } else if (!strcmp(key, "width") && vcodec) {
                        vcodec->width = num_val;
                    } else if (!strcmp(key, "height") && vcodec) {
                        vcodec->height = num_val;
                    }
                }
            }
        }

        if (!strcmp(key, "duration")        ||
            !strcmp(key, "filesize")        ||
            !strcmp(key, "width")           ||
            !strcmp(key, "height")          ||
            !strcmp(key, "videodatarate")   ||
            !strcmp(key, "framerate")       ||
            !strcmp(key, "videocodecid")    ||
            !strcmp(key, "audiodatarate")   ||
            !strcmp(key, "audiosamplerate") ||
            !strcmp(key, "audiosamplesize") ||
            !strcmp(key, "stereo")          ||
            !strcmp(key, "audiocodecid")    ||
            !strcmp(key, "datastream"))
            return 0;

        s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;
        if (amf_type == AMF_DATA_TYPE_BOOL) {
            av_strlcpy(str_val, num_val > 0 ? "true" : "false",
                       sizeof(str_val));
            av_dict_set(&s->metadata, key, str_val, 0);
        } else if (amf_type == AMF_DATA_TYPE_NUMBER) {
            snprintf(str_val, sizeof(str_val), "%.f", num_val);
            av_dict_set(&s->metadata, key, str_val, 0);
        } else if (amf_type == AMF_DATA_TYPE_STRING)
            av_dict_set(&s->metadata, key, str_val, 0);
    }

    return 0;
}

static int flv_read_metabody(AVFormatContext *s, int64_t next_pos)
{
    AMFDataType type;
    AVStream *stream, *astream, *vstream;
    AVIOContext *ioc;
    int i;
    // only needs to hold the string "onMetaData".
    // Anything longer is something we don't want.
    char buffer[11];

    astream = NULL;
    vstream = NULL;
    ioc     = s->pb;

    // first object needs to be "onMetaData" string
    type = avio_r8(ioc);
    if (type != AMF_DATA_TYPE_STRING ||
        amf_get_string(ioc, buffer, sizeof(buffer)) < 0)
        return -1;

    if (!strcmp(buffer, "onTextData"))
        return 1;

    if (strcmp(buffer, "onMetaData") && strcmp(buffer, "onCuePoint"))
        return -1;

    // find the streams now so that amf_parse_object doesn't need to do
    // the lookup every time it is called.
    for (i = 0; i < s->nb_streams; i++) {
        stream = s->streams[i];
        if (stream->codec->codec_type == AVMEDIA_TYPE_AUDIO)
            astream = stream;
        else if (stream->codec->codec_type == AVMEDIA_TYPE_VIDEO)
            vstream = stream;
    }

    // parse the second object (we want a mixed array)
    if (amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
        return -1;

    return 0;
}

static int flv_read_header(AVFormatContext *s)
{
    int offset, flags;

    avio_skip(s->pb, 4);
    flags = avio_r8(s->pb);

    s->ctx_flags |= AVFMTCTX_NOHEADER;

    if (flags & FLV_HEADER_FLAG_HASVIDEO)
        if (!create_stream(s, AVMEDIA_TYPE_VIDEO))
            return AVERROR(ENOMEM);
    if (flags & FLV_HEADER_FLAG_HASAUDIO)
        if (!create_stream(s, AVMEDIA_TYPE_AUDIO))
            return AVERROR(ENOMEM);

    offset = avio_rb32(s->pb);
    avio_seek(s->pb, offset, SEEK_SET);
    avio_skip(s->pb, 4);

    s->start_time = 0;

    return 0;
}

static int flv_read_close(AVFormatContext *s)
{
    FLVContext *flv = s->priv_data;
    av_freep(&flv->new_extradata[0]);
    av_freep(&flv->new_extradata[1]);
    return 0;
}

static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
{
    av_free(st->codec->extradata);
    st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!st->codec->extradata)
        return AVERROR(ENOMEM);
    st->codec->extradata_size = size;
    avio_read(s->pb, st->codec->extradata, st->codec->extradata_size);
    return 0;
}

static int flv_queue_extradata(FLVContext *flv, AVIOContext *pb, int stream,
                               int size)
{
    av_free(flv->new_extradata[stream]);
    flv->new_extradata[stream] = av_mallocz(size +
                                            FF_INPUT_BUFFER_PADDING_SIZE);
    if (!flv->new_extradata[stream])
        return AVERROR(ENOMEM);
    flv->new_extradata_size[stream] = size;
    avio_read(pb, flv->new_extradata[stream], size);
    return 0;
}

static void clear_index_entries(AVFormatContext *s, int64_t pos)
{
    int i, j, out;
    av_log(s, AV_LOG_WARNING,
           "Found invalid index entries, clearing the index.\n");
    for (i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];
        /* Remove all index entries that point to >= pos */
        out = 0;
        for (j = 0; j < st->nb_index_entries; j++)
            if (st->index_entries[j].pos < pos)
                st->index_entries[out++] = st->index_entries[j];
        st->nb_index_entries = out;
    }
}

static int amf_skip_tag(AVIOContext *pb, AMFDataType type)
{
    int nb = -1, ret, parse_name = 1;

    switch (type) {
    case AMF_DATA_TYPE_NUMBER:
        avio_skip(pb, 8);
        break;
    case AMF_DATA_TYPE_BOOL:
        avio_skip(pb, 1);
        break;
    case AMF_DATA_TYPE_STRING:
        avio_skip(pb, avio_rb16(pb));
        break;
    case AMF_DATA_TYPE_ARRAY:
        parse_name = 0;
    case AMF_DATA_TYPE_MIXEDARRAY:
        nb = avio_rb32(pb);
    case AMF_DATA_TYPE_OBJECT:
        while(!pb->eof_reached && (nb-- > 0 || type != AMF_DATA_TYPE_ARRAY)) {
            if (parse_name) {
                int size = avio_rb16(pb);
                if (!size) {
                    avio_skip(pb, 1);
                    break;
                }
                avio_skip(pb, size);
            }
            if ((ret = amf_skip_tag(pb, avio_r8(pb))) < 0)
                return ret;
        }
        break;
    case AMF_DATA_TYPE_NULL:
    case AMF_DATA_TYPE_OBJECT_END:
        break;
    default:
        return AVERROR_INVALIDDATA;
    }
    return 0;
}

static int flv_data_packet(AVFormatContext *s, AVPacket *pkt,
                           int64_t dts, int64_t next)
{
    AVIOContext *pb = s->pb;
    AVStream *st    = NULL;
    char buf[20];
    int ret = AVERROR_INVALIDDATA;
    int i, length = -1;

    switch (avio_r8(pb)) {
    case AMF_DATA_TYPE_MIXEDARRAY:
        avio_seek(pb, 4, SEEK_CUR);
    case AMF_DATA_TYPE_OBJECT:
        break;
    default:
        goto skip;
    }

    while ((ret = amf_get_string(pb, buf, sizeof(buf))) > 0) {
        AMFDataType type = avio_r8(pb);
        if (type == AMF_DATA_TYPE_STRING && !strcmp(buf, "text")) {
            length = avio_rb16(pb);
            ret    = av_get_packet(pb, pkt, length);
            if (ret < 0)
                goto skip;
            else
                break;
        } else {
            if ((ret = amf_skip_tag(pb, type)) < 0)
                goto skip;
        }
    }

    if (length < 0) {
        ret = AVERROR_INVALIDDATA;
        goto skip;
    }

    for (i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        if (st->codec->codec_type == AVMEDIA_TYPE_DATA)
            break;
    }

    if (i == s->nb_streams) {
        st = create_stream(s, AVMEDIA_TYPE_DATA);
        if (!st)
            return AVERROR(ENOMEM);
        st->codec->codec_id = AV_CODEC_ID_TEXT;
    }

    pkt->dts  = dts;
    pkt->pts  = dts;
    pkt->size = ret;

    pkt->stream_index = st->index;
    pkt->flags       |= AV_PKT_FLAG_KEY;

skip:
    avio_seek(s->pb, next + 4, SEEK_SET);

    return ret;
}

static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    FLVContext *flv = s->priv_data;
    int ret, i, type, size, flags, is_audio;
    int64_t next, pos;
    int64_t dts, pts = AV_NOPTS_VALUE;
    int sample_rate = 0, channels = 0;
    AVStream *st    = NULL;

    /* pkt size is repeated at end. skip it */
    for (;; avio_skip(s->pb, 4)) {
        pos  = avio_tell(s->pb);
        type = avio_r8(s->pb);
        size = avio_rb24(s->pb);
        dts  = avio_rb24(s->pb);
        dts |= avio_r8(s->pb) << 24;
        av_log(s, AV_LOG_TRACE, "type:%d, size:%d, dts:%"PRId64"\n", type, size, dts);
        if (s->pb->eof_reached)
            return AVERROR_EOF;
        avio_skip(s->pb, 3); /* stream id, always 0 */
        flags = 0;

        if (flv->validate_next < flv->validate_count) {
            int64_t validate_pos = flv->validate_index[flv->validate_next].pos;
            if (pos == validate_pos) {
                if (FFABS(dts - flv->validate_index[flv->validate_next].dts) <=
                    VALIDATE_INDEX_TS_THRESH) {
                    flv->validate_next++;
                } else {
                    clear_index_entries(s, validate_pos);
                    flv->validate_count = 0;
                }
            } else if (pos > validate_pos) {
                clear_index_entries(s, validate_pos);
                flv->validate_count = 0;
            }
        }

        if (size == 0)
            continue;

        next = size + avio_tell(s->pb);

        if (type == FLV_TAG_TYPE_AUDIO) {
            is_audio = 1;
            flags    = avio_r8(s->pb);
            size--;
        } else if (type == FLV_TAG_TYPE_VIDEO) {
            is_audio = 0;
            flags    = avio_r8(s->pb);
            size--;
            if ((flags & 0xf0) == 0x50) /* video info / command frame */
                goto skip;
        } else {
            if (type == FLV_TAG_TYPE_META && size > 13 + 1 + 4)
                if (flv_read_metabody(s, next) > 0) {
                    return flv_data_packet(s, pkt, dts, next);
                } else /* skip packet */
                    av_log(s, AV_LOG_DEBUG,
                           "Skipping flv packet: type %d, size %d, flags %d.\n",
                           type, size, flags);

skip:
            avio_seek(s->pb, next, SEEK_SET);
            continue;
        }

        /* skip empty data packets */
        if (!size)
            continue;

        /* now find stream */
        for (i = 0; i < s->nb_streams; i++) {
            st = s->streams[i];
            if (is_audio && st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
                if (flv_same_audio_codec(st->codec, flags))
                    break;
            } else if (!is_audio &&
                       st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
                if (flv_same_video_codec(st->codec, flags))
                    break;
            }
        }
        if (i == s->nb_streams) {
            st = create_stream(s, is_audio ? AVMEDIA_TYPE_AUDIO
                                           : AVMEDIA_TYPE_VIDEO);
            if (!st)
                return AVERROR(ENOMEM);
        }
        av_log(s, AV_LOG_TRACE, "%d %X %d \n", is_audio, flags, st->discard);

        if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||
            is_audio)
            av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);

        if ((st->discard >= AVDISCARD_NONKEY &&
             !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY || is_audio)) ||
            (st->discard >= AVDISCARD_BIDIR &&
             ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio)) ||
            st->discard >= AVDISCARD_ALL) {
            avio_seek(s->pb, next, SEEK_SET);
            continue;
        }
        break;
    }

    // if not streamed and no duration from metadata then seek to end to find
    // the duration from the timestamps
    if (s->pb->seekable && (!s->duration || s->duration == AV_NOPTS_VALUE)) {
        int size;
        const int64_t pos   = avio_tell(s->pb);
        // Read the last 4 bytes of the file, this should be the size of the
        // previous FLV tag. Use the timestamp of its payload as duration.
        const int64_t fsize = avio_size(s->pb);
        avio_seek(s->pb, fsize - 4, SEEK_SET);
        size = avio_rb32(s->pb);
        // Seek to the start of the last FLV tag at position (fsize - 4 - size)
        // but skip the byte indicating the type.
        avio_seek(s->pb, fsize - 3 - size, SEEK_SET);
        if (size == avio_rb24(s->pb) + 11) {
            uint32_t ts = avio_rb24(s->pb);
            ts         |= avio_r8(s->pb) << 24;
            s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
        }
        avio_seek(s->pb, pos, SEEK_SET);
    }

    if (is_audio) {
        int bits_per_coded_sample;
        channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
        sample_rate = 44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >>
                                FLV_AUDIO_SAMPLERATE_OFFSET) >> 3;
        bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
        if (!st->codec->channels || !st->codec->sample_rate ||
            !st->codec->bits_per_coded_sample) {
            st->codec->channels              = channels;
            st->codec->channel_layout        = channels == 1
                                               ? AV_CH_LAYOUT_MONO
                                               : AV_CH_LAYOUT_STEREO;
            st->codec->sample_rate           = sample_rate;
            st->codec->bits_per_coded_sample = bits_per_coded_sample;
        }
        if (!st->codec->codec_id) {
            flv_set_audio_codec(s, st, st->codec,
                                flags & FLV_AUDIO_CODECID_MASK);
            flv->last_sample_rate =
            sample_rate           = st->codec->sample_rate;
            flv->last_channels    =
            channels              = st->codec->channels;
        } else {
            AVCodecContext ctx;
            ctx.sample_rate = sample_rate;
            ctx.bits_per_coded_sample = bits_per_coded_sample;
            flv_set_audio_codec(s, st, &ctx, flags & FLV_AUDIO_CODECID_MASK);
            sample_rate = ctx.sample_rate;
        }
    } else {
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK, 1);
    }

    if (st->codec->codec_id == AV_CODEC_ID_AAC ||
        st->codec->codec_id == AV_CODEC_ID_H264) {
        int type = avio_r8(s->pb);
        size--;
        if (st->codec->codec_id == AV_CODEC_ID_H264) {
            // sign extension
            int32_t cts = (avio_rb24(s->pb) + 0xff800000) ^ 0xff800000;
            pts = dts + cts;
            if (cts < 0 && !flv->wrong_dts) { // dts might be wrong
                flv->wrong_dts = 1;
                av_log(s, AV_LOG_WARNING,
                       "Negative cts, previous timestamps might be wrong.\n");
            }
        }
        if (type == 0) {
            if (st->codec->extradata) {
                if ((ret = flv_queue_extradata(flv, s->pb, is_audio, size)) < 0)
                    return ret;
                ret = AVERROR(EAGAIN);
                goto leave;
            }
            if ((ret = flv_get_extradata(s, st, size)) < 0)
                return ret;
            if (st->codec->codec_id == AV_CODEC_ID_AAC) {
                MPEG4AudioConfig cfg;

                /* Workaround for buggy Omnia A/XE encoder */
                AVDictionaryEntry *t = av_dict_get(s->metadata, "Encoder", NULL, 0);
                if (t && !strcmp(t->value, "Omnia A/XE"))
                    st->codec->extradata_size = 2;

                avpriv_mpeg4audio_get_config(&cfg, st->codec->extradata,
                                             st->codec->extradata_size * 8, 1);
                st->codec->channels       = cfg.channels;
                st->codec->channel_layout = 0;
                if (cfg.ext_sample_rate)
                    st->codec->sample_rate = cfg.ext_sample_rate;
                else
                    st->codec->sample_rate = cfg.sample_rate;
                av_log(s, AV_LOG_TRACE, "mp4a config channels %d sample rate %d\n",
                        st->codec->channels, st->codec->sample_rate);
            }

            ret = AVERROR(EAGAIN);
            goto leave;
        }
    }

    /* skip empty data packets */
    if (!size) {
        ret = AVERROR(EAGAIN);
        goto leave;
    }

    ret = av_get_packet(s->pb, pkt, size);
    if (ret < 0)
        return AVERROR(EIO);
    /* note: we need to modify the packet size here to handle the last
     * packet */
    pkt->size         = ret;
    pkt->dts          = dts;
    pkt->pts          = pts == AV_NOPTS_VALUE ? dts : pts;
    pkt->stream_index = st->index;
    if (flv->new_extradata[is_audio]) {
        uint8_t *side = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
                                                flv->new_extradata_size[is_audio]);
        if (side) {
            memcpy(side, flv->new_extradata[is_audio],
                   flv->new_extradata_size[is_audio]);
            av_freep(&flv->new_extradata[is_audio]);
            flv->new_extradata_size[is_audio] = 0;
        }
    }
    if (is_audio && (sample_rate != flv->last_sample_rate ||
                     channels    != flv->last_channels)) {
        flv->last_sample_rate = sample_rate;
        flv->last_channels    = channels;
        ff_add_param_change(pkt, channels, 0, sample_rate, 0, 0);
    }

    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
        pkt->flags |= AV_PKT_FLAG_KEY;

leave:
    avio_skip(s->pb, 4);
    return ret;
}

static int flv_read_seek(AVFormatContext *s, int stream_index,
                         int64_t ts, int flags)
{
    FLVContext *flv = s->priv_data;
    flv->validate_count = 0;
    return avio_seek_time(s->pb, stream_index, ts, flags);
}

#define OFFSET(x) offsetof(FLVContext, x)
#define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
    { "flv_metadata", "Allocate streams according to the onMetaData array", OFFSET(trust_metadata), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, VD },
    { NULL }
};

static const AVClass class = {
    .class_name = "flvdec",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVInputFormat ff_flv_demuxer = {
    .name           = "flv",
    .long_name      = NULL_IF_CONFIG_SMALL("FLV (Flash Video)"),
    .priv_data_size = sizeof(FLVContext),
    .read_probe     = flv_probe,
    .read_header    = flv_read_header,
    .read_packet    = flv_read_packet,
    .read_seek      = flv_read_seek,
    .read_close     = flv_read_close,
    .extensions     = "flv",
    .priv_class     = &class,
};