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ffmpeg / libavformat / mpeg.c @ 72415b2a

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1
/*
2
 * MPEG1/2 demuxer
3
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
4
 *
5
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
9
 * License as published by the Free Software Foundation; either
10
 * version 2.1 of the License, or (at your option) any later version.
11
 *
12
 * FFmpeg is distributed in the hope that it will be useful,
13
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * Lesser General Public License for more details.
16
 *
17
 * You should have received a copy of the GNU Lesser General Public
18
 * License along with FFmpeg; if not, write to the Free Software
19
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21

    
22
#include "avformat.h"
23
#include "mpeg.h"
24

    
25
//#define DEBUG_SEEK
26

    
27
#undef NDEBUG
28
#include <assert.h>
29

    
30
/*********************************************/
31
/* demux code */
32

    
33
#define MAX_SYNC_SIZE 100000
34

    
35
static int check_pes(uint8_t *p, uint8_t *end){
36
    int pes1;
37
    int pes2=      (p[3] & 0xC0) == 0x80
38
                && (p[4] & 0xC0) != 0x40
39
                &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));
40

    
41
    for(p+=3; p<end && *p == 0xFF; p++);
42
    if((*p&0xC0) == 0x40) p+=2;
43
    if((*p&0xF0) == 0x20){
44
        pes1= p[0]&p[2]&p[4]&1;
45
    }else if((*p&0xF0) == 0x30){
46
        pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
47
    }else
48
        pes1 = *p == 0x0F;
49

    
50
    return pes1||pes2;
51
}
52

    
53
static int mpegps_probe(AVProbeData *p)
54
{
55
    uint32_t code= -1;
56
    int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
57
    int i;
58
    int score=0;
59

    
60
    for(i=0; i<p->buf_size; i++){
61
        code = (code<<8) + p->buf[i];
62
        if ((code & 0xffffff00) == 0x100) {
63
            int pes= check_pes(p->buf+i, p->buf+p->buf_size);
64

    
65
            if(code == SYSTEM_HEADER_START_CODE) sys++;
66
            else if(code == PRIVATE_STREAM_1)    priv1++;
67
            else if(code == PACK_START_CODE)     pspack++;
68
            else if((code & 0xf0) == VIDEO_ID &&  pes) vid++;
69
            else if((code & 0xe0) == AUDIO_ID &&  pes) audio++;
70

    
71
            else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
72
            else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
73
        }
74
    }
75

    
76
    if(vid+audio > invalid)     /* invalid VDR files nd short PES streams */
77
        score= AVPROBE_SCORE_MAX/4;
78

    
79
//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, invalid, p->buf_size);
80
    if(sys>invalid && sys*9 <= pspack*10)
81
        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
82
    if(pspack > invalid && (priv1+vid+audio)*10 >= pspack*9)
83
        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
84
    if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */
85
        return (audio > 12 || vid > 3) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4;
86

    
87
    //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
88
    //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6
89
    return score;
90
}
91

    
92

    
93
typedef struct MpegDemuxContext {
94
    int32_t header_state;
95
    unsigned char psm_es_type[256];
96
    int sofdec;
97
} MpegDemuxContext;
98

    
99
static int mpegps_read_header(AVFormatContext *s,
100
                              AVFormatParameters *ap)
101
{
102
    MpegDemuxContext *m = s->priv_data;
103
    const char *sofdec = "Sofdec";
104
    int v, i = 0;
105

    
106
    m->header_state = 0xff;
107
    s->ctx_flags |= AVFMTCTX_NOHEADER;
108

    
109
    m->sofdec = -1;
110
    do {
111
        v = get_byte(s->pb);
112
        m->header_state = m->header_state << 8 | v;
113
        m->sofdec++;
114
    } while (v == sofdec[i] && i++ < 6);
115

    
116
    m->sofdec = (m->sofdec == 6) ? 1 : 0;
117

    
118
    /* no need to do more */
119
    return 0;
120
}
121

    
122
static int64_t get_pts(ByteIOContext *pb, int c)
123
{
124
    uint8_t buf[5];
125

    
126
    buf[0] = c<0 ? get_byte(pb) : c;
127
    get_buffer(pb, buf+1, 4);
128

    
129
    return ff_parse_pes_pts(buf);
130
}
131

    
132
static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
133
                                int32_t *header_state)
134
{
135
    unsigned int state, v;
136
    int val, n;
137

    
138
    state = *header_state;
139
    n = *size_ptr;
140
    while (n > 0) {
141
        if (url_feof(pb))
142
            break;
143
        v = get_byte(pb);
144
        n--;
145
        if (state == 0x000001) {
146
            state = ((state << 8) | v) & 0xffffff;
147
            val = state;
148
            goto found;
149
        }
150
        state = ((state << 8) | v) & 0xffffff;
151
    }
152
    val = -1;
153
 found:
154
    *header_state = state;
155
    *size_ptr = n;
156
    return val;
157
}
158

    
159
#if 0 /* unused, remove? */
160
/* XXX: optimize */
161
static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
162
{
163
    int64_t pos, pos_start;
164
    int max_size, start_code;
165

166
    max_size = *size_ptr;
167
    pos_start = url_ftell(pb);
168

169
    /* in order to go faster, we fill the buffer */
170
    pos = pos_start - 16386;
171
    if (pos < 0)
172
        pos = 0;
173
    url_fseek(pb, pos, SEEK_SET);
174
    get_byte(pb);
175

176
    pos = pos_start;
177
    for(;;) {
178
        pos--;
179
        if (pos < 0 || (pos_start - pos) >= max_size) {
180
            start_code = -1;
181
            goto the_end;
182
        }
183
        url_fseek(pb, pos, SEEK_SET);
184
        start_code = get_be32(pb);
185
        if ((start_code & 0xffffff00) == 0x100)
186
            break;
187
    }
188
 the_end:
189
    *size_ptr = pos_start - pos;
190
    return start_code;
191
}
192
#endif
193

    
194
/**
195
 * Extracts stream types from a program stream map
196
 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
197
 *
198
 * @return number of bytes occupied by PSM in the bitstream
199
 */
200
static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
201
{
202
    int psm_length, ps_info_length, es_map_length;
203

    
204
    psm_length = get_be16(pb);
205
    get_byte(pb);
206
    get_byte(pb);
207
    ps_info_length = get_be16(pb);
208

    
209
    /* skip program_stream_info */
210
    url_fskip(pb, ps_info_length);
211
    es_map_length = get_be16(pb);
212

    
213
    /* at least one es available? */
214
    while (es_map_length >= 4){
215
        unsigned char type      = get_byte(pb);
216
        unsigned char es_id     = get_byte(pb);
217
        uint16_t es_info_length = get_be16(pb);
218
        /* remember mapping from stream id to stream type */
219
        m->psm_es_type[es_id] = type;
220
        /* skip program_stream_info */
221
        url_fskip(pb, es_info_length);
222
        es_map_length -= 4 + es_info_length;
223
    }
224
    get_be32(pb); /* crc32 */
225
    return 2 + psm_length;
226
}
227

    
228
/* read the next PES header. Return its position in ppos
229
   (if not NULL), and its start code, pts and dts.
230
 */
231
static int mpegps_read_pes_header(AVFormatContext *s,
232
                                  int64_t *ppos, int *pstart_code,
233
                                  int64_t *ppts, int64_t *pdts)
234
{
235
    MpegDemuxContext *m = s->priv_data;
236
    int len, size, startcode, c, flags, header_len;
237
    int pes_ext, ext2_len, id_ext, skip;
238
    int64_t pts, dts;
239
    int64_t last_sync= url_ftell(s->pb);
240

    
241
 error_redo:
242
        url_fseek(s->pb, last_sync, SEEK_SET);
243
 redo:
244
        /* next start code (should be immediately after) */
245
        m->header_state = 0xff;
246
        size = MAX_SYNC_SIZE;
247
        startcode = find_next_start_code(s->pb, &size, &m->header_state);
248
        last_sync = url_ftell(s->pb);
249
    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(s->pb));
250
    if (startcode < 0){
251
        if(url_feof(s->pb))
252
            return AVERROR_EOF;
253
        //FIXME we should remember header_state
254
        return AVERROR(EAGAIN);
255
    }
256

    
257
    if (startcode == PACK_START_CODE)
258
        goto redo;
259
    if (startcode == SYSTEM_HEADER_START_CODE)
260
        goto redo;
261
    if (startcode == PADDING_STREAM) {
262
        url_fskip(s->pb, get_be16(s->pb));
263
        goto redo;
264
    }
265
    if (startcode == PRIVATE_STREAM_2) {
266
        len = get_be16(s->pb);
267
        if (!m->sofdec) {
268
            while (len-- >= 6) {
269
                if (get_byte(s->pb) == 'S') {
270
                    uint8_t buf[5];
271
                    get_buffer(s->pb, buf, sizeof(buf));
272
                    m->sofdec = !memcmp(buf, "ofdec", 5);
273
                    len -= sizeof(buf);
274
                    break;
275
                }
276
            }
277
            m->sofdec -= !m->sofdec;
278
        }
279
        url_fskip(s->pb, len);
280
        goto redo;
281
    }
282
    if (startcode == PROGRAM_STREAM_MAP) {
283
        mpegps_psm_parse(m, s->pb);
284
        goto redo;
285
    }
286

    
287
    /* find matching stream */
288
    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
289
          (startcode >= 0x1e0 && startcode <= 0x1ef) ||
290
          (startcode == 0x1bd) || (startcode == 0x1fd)))
291
        goto redo;
292
    if (ppos) {
293
        *ppos = url_ftell(s->pb) - 4;
294
    }
295
    len = get_be16(s->pb);
296
    pts =
297
    dts = AV_NOPTS_VALUE;
298
    /* stuffing */
299
    for(;;) {
300
        if (len < 1)
301
            goto error_redo;
302
        c = get_byte(s->pb);
303
        len--;
304
        /* XXX: for mpeg1, should test only bit 7 */
305
        if (c != 0xff)
306
            break;
307
    }
308
    if ((c & 0xc0) == 0x40) {
309
        /* buffer scale & size */
310
        get_byte(s->pb);
311
        c = get_byte(s->pb);
312
        len -= 2;
313
    }
314
    if ((c & 0xe0) == 0x20) {
315
        dts = pts = get_pts(s->pb, c);
316
        len -= 4;
317
        if (c & 0x10){
318
            dts = get_pts(s->pb, -1);
319
            len -= 5;
320
        }
321
    } else if ((c & 0xc0) == 0x80) {
322
        /* mpeg 2 PES */
323
#if 0 /* some streams have this field set for no apparent reason */
324
        if ((c & 0x30) != 0) {
325
            /* Encrypted multiplex not handled */
326
            goto redo;
327
        }
328
#endif
329
        flags = get_byte(s->pb);
330
        header_len = get_byte(s->pb);
331
        len -= 2;
332
        if (header_len > len)
333
            goto error_redo;
334
        len -= header_len;
335
        if (flags & 0x80) {
336
            dts = pts = get_pts(s->pb, -1);
337
            header_len -= 5;
338
            if (flags & 0x40) {
339
                dts = get_pts(s->pb, -1);
340
                header_len -= 5;
341
            }
342
        }
343
        if (flags & 0x3f && header_len == 0){
344
            flags &= 0xC0;
345
            av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");
346
        }
347
        if (flags & 0x01) { /* PES extension */
348
            pes_ext = get_byte(s->pb);
349
            header_len--;
350
            /* Skip PES private data, program packet sequence counter and P-STD buffer */
351
            skip = (pes_ext >> 4) & 0xb;
352
            skip += skip & 0x9;
353
            if (pes_ext & 0x40 || skip > header_len){
354
                av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);
355
                pes_ext=skip=0;
356
            }
357
            url_fskip(s->pb, skip);
358
            header_len -= skip;
359

    
360
            if (pes_ext & 0x01) { /* PES extension 2 */
361
                ext2_len = get_byte(s->pb);
362
                header_len--;
363
                if ((ext2_len & 0x7f) > 0) {
364
                    id_ext = get_byte(s->pb);
365
                    if ((id_ext & 0x80) == 0)
366
                        startcode = ((startcode & 0xff) << 8) | id_ext;
367
                    header_len--;
368
                }
369
            }
370
        }
371
        if(header_len < 0)
372
            goto error_redo;
373
        url_fskip(s->pb, header_len);
374
    }
375
    else if( c!= 0xf )
376
        goto redo;
377

    
378
    if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
379
        startcode = get_byte(s->pb);
380
        len--;
381
        if (startcode >= 0x80 && startcode <= 0xcf) {
382
            /* audio: skip header */
383
            get_byte(s->pb);
384
            get_byte(s->pb);
385
            get_byte(s->pb);
386
            len -= 3;
387
            if (startcode >= 0xb0 && startcode <= 0xbf) {
388
                /* MLP/TrueHD audio has a 4-byte header */
389
                get_byte(s->pb);
390
                len--;
391
            }
392
        }
393
    }
394
    if(len<0)
395
        goto error_redo;
396
    if(dts != AV_NOPTS_VALUE && ppos){
397
        int i;
398
        for(i=0; i<s->nb_streams; i++){
399
            if(startcode == s->streams[i]->id &&
400
               !url_is_streamed(s->pb) /* index useless on streams anyway */) {
401
                ff_reduce_index(s, i);
402
                av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
403
            }
404
        }
405
    }
406

    
407
    *pstart_code = startcode;
408
    *ppts = pts;
409
    *pdts = dts;
410
    return len;
411
}
412

    
413
static int mpegps_read_packet(AVFormatContext *s,
414
                              AVPacket *pkt)
415
{
416
    MpegDemuxContext *m = s->priv_data;
417
    AVStream *st;
418
    int len, startcode, i, es_type;
419
    enum CodecID codec_id = CODEC_ID_NONE;
420
    enum AVMediaType type;
421
    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
422
    uint8_t av_uninit(dvdaudio_substream_type);
423

    
424
 redo:
425
    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
426
    if (len < 0)
427
        return len;
428

    
429
    if(startcode == 0x1bd) {
430
        dvdaudio_substream_type = get_byte(s->pb);
431
        url_fskip(s->pb, 3);
432
        len -= 4;
433
    }
434

    
435
    /* now find stream */
436
    for(i=0;i<s->nb_streams;i++) {
437
        st = s->streams[i];
438
        if (st->id == startcode)
439
            goto found;
440
    }
441

    
442
    es_type = m->psm_es_type[startcode & 0xff];
443
    if(es_type > 0 && es_type != STREAM_TYPE_PRIVATE_DATA){
444
        if(es_type == STREAM_TYPE_VIDEO_MPEG1){
445
            codec_id = CODEC_ID_MPEG2VIDEO;
446
            type = AVMEDIA_TYPE_VIDEO;
447
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
448
            codec_id = CODEC_ID_MPEG2VIDEO;
449
            type = AVMEDIA_TYPE_VIDEO;
450
        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
451
                  es_type == STREAM_TYPE_AUDIO_MPEG2){
452
            codec_id = CODEC_ID_MP3;
453
            type = AVMEDIA_TYPE_AUDIO;
454
        } else if(es_type == STREAM_TYPE_AUDIO_AAC){
455
            codec_id = CODEC_ID_AAC;
456
            type = AVMEDIA_TYPE_AUDIO;
457
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
458
            codec_id = CODEC_ID_MPEG4;
459
            type = AVMEDIA_TYPE_VIDEO;
460
        } else if(es_type == STREAM_TYPE_VIDEO_H264){
461
            codec_id = CODEC_ID_H264;
462
            type = AVMEDIA_TYPE_VIDEO;
463
        } else if(es_type == STREAM_TYPE_AUDIO_AC3){
464
            codec_id = CODEC_ID_AC3;
465
            type = AVMEDIA_TYPE_AUDIO;
466
        } else {
467
            goto skip;
468
        }
469
    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
470
        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
471
        unsigned char buf[8];
472
        get_buffer(s->pb, buf, 8);
473
        url_fseek(s->pb, -8, SEEK_CUR);
474
        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
475
            codec_id = CODEC_ID_CAVS;
476
        else
477
            codec_id = CODEC_ID_PROBE;
478
        type = AVMEDIA_TYPE_VIDEO;
479
    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
480
        type = AVMEDIA_TYPE_AUDIO;
481
        codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
482
    } else if (startcode >= 0x80 && startcode <= 0x87) {
483
        type = AVMEDIA_TYPE_AUDIO;
484
        codec_id = CODEC_ID_AC3;
485
    } else if (  ( startcode >= 0x88 && startcode <= 0x8f)
486
               ||( startcode >= 0x98 && startcode <= 0x9f)) {
487
        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
488
        type = AVMEDIA_TYPE_AUDIO;
489
        codec_id = CODEC_ID_DTS;
490
    } else if (startcode >= 0xa0 && startcode <= 0xaf) {
491
        type = AVMEDIA_TYPE_AUDIO;
492
        /* 16 bit form will be handled as CODEC_ID_PCM_S16BE */
493
        codec_id = CODEC_ID_PCM_DVD;
494
    } else if (startcode >= 0xb0 && startcode <= 0xbf) {
495
        type = AVMEDIA_TYPE_AUDIO;
496
        codec_id = CODEC_ID_TRUEHD;
497
    } else if (startcode >= 0xc0 && startcode <= 0xcf) {
498
        /* Used for both AC-3 and E-AC-3 in EVOB files */
499
        type = AVMEDIA_TYPE_AUDIO;
500
        codec_id = CODEC_ID_AC3;
501
    } else if (startcode >= 0x20 && startcode <= 0x3f) {
502
        type = AVMEDIA_TYPE_SUBTITLE;
503
        codec_id = CODEC_ID_DVD_SUBTITLE;
504
    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
505
        type = AVMEDIA_TYPE_VIDEO;
506
        codec_id = CODEC_ID_VC1;
507
    } else if (startcode == 0x1bd) {
508
        // check dvd audio substream type
509
        type = AVMEDIA_TYPE_AUDIO;
510
        switch(dvdaudio_substream_type & 0xe0) {
511
        case 0xa0:  codec_id = CODEC_ID_PCM_DVD;
512
                    break;
513
        case 0x80:  if((dvdaudio_substream_type & 0xf8) == 0x88)
514
                         codec_id = CODEC_ID_DTS;
515
                    else codec_id = CODEC_ID_AC3;
516
                    break;
517
        default:    av_log(s, AV_LOG_ERROR, "Unknown 0x1bd sub-stream\n");
518
                    goto skip;
519
        }
520
    } else {
521
    skip:
522
        /* skip packet */
523
        url_fskip(s->pb, len);
524
        goto redo;
525
    }
526
    /* no stream found: add a new stream */
527
    st = av_new_stream(s, startcode);
528
    if (!st)
529
        goto skip;
530
    st->codec->codec_type = type;
531
    st->codec->codec_id = codec_id;
532
    if (codec_id != CODEC_ID_PCM_S16BE)
533
        st->need_parsing = AVSTREAM_PARSE_FULL;
534
 found:
535
    if(st->discard >= AVDISCARD_ALL)
536
        goto skip;
537
    if ((startcode >= 0xa0 && startcode <= 0xaf) ||
538
        (startcode == 0x1bd && ((dvdaudio_substream_type & 0xe0) == 0xa0))) {
539
        int b1, freq;
540

    
541
        /* for LPCM, we just skip the header and consider it is raw
542
           audio data */
543
        if (len <= 3)
544
            goto skip;
545
        get_byte(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
546
        b1 = get_byte(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
547
        get_byte(s->pb); /* dynamic range control (0x80 = off) */
548
        len -= 3;
549
        freq = (b1 >> 4) & 3;
550
        st->codec->sample_rate = lpcm_freq_tab[freq];
551
        st->codec->channels = 1 + (b1 & 7);
552
        st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;
553
        st->codec->bit_rate = st->codec->channels *
554
                              st->codec->sample_rate *
555
                              st->codec->bits_per_coded_sample;
556
        if (st->codec->bits_per_coded_sample == 16)
557
            st->codec->codec_id = CODEC_ID_PCM_S16BE;
558
        else if (st->codec->bits_per_coded_sample == 28)
559
            return AVERROR(EINVAL);
560
    }
561
    av_new_packet(pkt, len);
562
    get_buffer(s->pb, pkt->data, pkt->size);
563
    pkt->pts = pts;
564
    pkt->dts = dts;
565
    pkt->pos = dummy_pos;
566
    pkt->stream_index = st->index;
567
#if 0
568
    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
569
           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
570
#endif
571

    
572
    return 0;
573
}
574

    
575
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
576
                               int64_t *ppos, int64_t pos_limit)
577
{
578
    int len, startcode;
579
    int64_t pos, pts, dts;
580

    
581
    pos = *ppos;
582
#ifdef DEBUG_SEEK
583
    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
584
#endif
585
    if (url_fseek(s->pb, pos, SEEK_SET) < 0)
586
        return AV_NOPTS_VALUE;
587

    
588
    for(;;) {
589
        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
590
        if (len < 0) {
591
#ifdef DEBUG_SEEK
592
            printf("none (ret=%d)\n", len);
593
#endif
594
            return AV_NOPTS_VALUE;
595
        }
596
        if (startcode == s->streams[stream_index]->id &&
597
            dts != AV_NOPTS_VALUE) {
598
            break;
599
        }
600
        url_fskip(s->pb, len);
601
    }
602
#ifdef DEBUG_SEEK
603
    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
604
#endif
605
    *ppos = pos;
606
    return dts;
607
}
608

    
609
AVInputFormat mpegps_demuxer = {
610
    "mpeg",
611
    NULL_IF_CONFIG_SMALL("MPEG-PS format"),
612
    sizeof(MpegDemuxContext),
613
    mpegps_probe,
614
    mpegps_read_header,
615
    mpegps_read_packet,
616
    NULL,
617
    NULL, //mpegps_read_seek,
618
    mpegps_read_dts,
619
    .flags = AVFMT_SHOW_IDS|AVFMT_TS_DISCONT,
620
};