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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 "internal.h"
24
#include "mpeg.h"
25

    
26
//#define DEBUG_SEEK
27

    
28
#undef NDEBUG
29
#include <assert.h>
30

    
31
/*********************************************/
32
/* demux code */
33

    
34
#define MAX_SYNC_SIZE 100000
35

    
36
static int check_pes(uint8_t *p, uint8_t *end){
37
    int pes1;
38
    int pes2=      (p[3] & 0xC0) == 0x80
39
                && (p[4] & 0xC0) != 0x40
40
                &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));
41

    
42
    for(p+=3; p<end && *p == 0xFF; p++);
43
    if((*p&0xC0) == 0x40) p+=2;
44
    if((*p&0xF0) == 0x20){
45
        pes1= p[0]&p[2]&p[4]&1;
46
    }else if((*p&0xF0) == 0x30){
47
        pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
48
    }else
49
        pes1 = *p == 0x0F;
50

    
51
    return pes1||pes2;
52
}
53

    
54
static int mpegps_probe(AVProbeData *p)
55
{
56
    uint32_t code= -1;
57
    int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
58
    int i;
59
    int score=0;
60

    
61
    for(i=0; i<p->buf_size; i++){
62
        code = (code<<8) + p->buf[i];
63
        if ((code & 0xffffff00) == 0x100) {
64
            int len= p->buf[i+1] << 8 | p->buf[i+2];
65
            int pes= check_pes(p->buf+i, p->buf+p->buf_size);
66

    
67
            if(code == SYSTEM_HEADER_START_CODE) sys++;
68
            else if(code == PACK_START_CODE)     pspack++;
69
            else if((code & 0xf0) == VIDEO_ID &&  pes) vid++;
70
            // skip pes payload to avoid start code emulation for private
71
            // and audio streams
72
            else if((code & 0xe0) == AUDIO_ID &&  pes) {audio++; i+=len;}
73
            else if(code == PRIVATE_STREAM_1  &&  pes) {priv1++; i+=len;}
74

    
75
            else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
76
            else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
77
            else if(code == PRIVATE_STREAM_1  && !pes) invalid++;
78
        }
79
    }
80

    
81
    if(vid+audio > invalid)     /* invalid VDR files nd short PES streams */
82
        score= AVPROBE_SCORE_MAX/4;
83

    
84
//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, invalid, p->buf_size);
85
    if(sys>invalid && sys*9 <= pspack*10)
86
        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
87
    if(pspack > invalid && (priv1+vid+audio)*10 >= pspack*9)
88
        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
89
    if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */
90
        return (audio > 12 || vid > 3) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4;
91

    
92
    //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
93
    //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6
94
    return score;
95
}
96

    
97

    
98
typedef struct MpegDemuxContext {
99
    int32_t header_state;
100
    unsigned char psm_es_type[256];
101
    int sofdec;
102
} MpegDemuxContext;
103

    
104
static int mpegps_read_header(AVFormatContext *s,
105
                              AVFormatParameters *ap)
106
{
107
    MpegDemuxContext *m = s->priv_data;
108
    const char *sofdec = "Sofdec";
109
    int v, i = 0;
110

    
111
    m->header_state = 0xff;
112
    s->ctx_flags |= AVFMTCTX_NOHEADER;
113

    
114
    m->sofdec = -1;
115
    do {
116
        v = avio_r8(s->pb);
117
        m->header_state = m->header_state << 8 | v;
118
        m->sofdec++;
119
    } while (v == sofdec[i] && i++ < 6);
120

    
121
    m->sofdec = (m->sofdec == 6) ? 1 : 0;
122

    
123
    /* no need to do more */
124
    return 0;
125
}
126

    
127
static int64_t get_pts(AVIOContext *pb, int c)
128
{
129
    uint8_t buf[5];
130

    
131
    buf[0] = c<0 ? avio_r8(pb) : c;
132
    avio_read(pb, buf+1, 4);
133

    
134
    return ff_parse_pes_pts(buf);
135
}
136

    
137
static int find_next_start_code(AVIOContext *pb, int *size_ptr,
138
                                int32_t *header_state)
139
{
140
    unsigned int state, v;
141
    int val, n;
142

    
143
    state = *header_state;
144
    n = *size_ptr;
145
    while (n > 0) {
146
        if (url_feof(pb))
147
            break;
148
        v = avio_r8(pb);
149
        n--;
150
        if (state == 0x000001) {
151
            state = ((state << 8) | v) & 0xffffff;
152
            val = state;
153
            goto found;
154
        }
155
        state = ((state << 8) | v) & 0xffffff;
156
    }
157
    val = -1;
158
 found:
159
    *header_state = state;
160
    *size_ptr = n;
161
    return val;
162
}
163

    
164
#if 0 /* unused, remove? */
165
/* XXX: optimize */
166
static int find_prev_start_code(AVIOContext *pb, int *size_ptr)
167
{
168
    int64_t pos, pos_start;
169
    int max_size, start_code;
170

171
    max_size = *size_ptr;
172
    pos_start = url_ftell(pb);
173

174
    /* in order to go faster, we fill the buffer */
175
    pos = pos_start - 16386;
176
    if (pos < 0)
177
        pos = 0;
178
    url_fseek(pb, pos, SEEK_SET);
179
    avio_r8(pb);
180

181
    pos = pos_start;
182
    for(;;) {
183
        pos--;
184
        if (pos < 0 || (pos_start - pos) >= max_size) {
185
            start_code = -1;
186
            goto the_end;
187
        }
188
        url_fseek(pb, pos, SEEK_SET);
189
        start_code = avio_rb32(pb);
190
        if ((start_code & 0xffffff00) == 0x100)
191
            break;
192
    }
193
 the_end:
194
    *size_ptr = pos_start - pos;
195
    return start_code;
196
}
197
#endif
198

    
199
/**
200
 * Extract stream types from a program stream map
201
 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
202
 *
203
 * @return number of bytes occupied by PSM in the bitstream
204
 */
205
static long mpegps_psm_parse(MpegDemuxContext *m, AVIOContext *pb)
206
{
207
    int psm_length, ps_info_length, es_map_length;
208

    
209
    psm_length = avio_rb16(pb);
210
    avio_r8(pb);
211
    avio_r8(pb);
212
    ps_info_length = avio_rb16(pb);
213

    
214
    /* skip program_stream_info */
215
    url_fskip(pb, ps_info_length);
216
    es_map_length = avio_rb16(pb);
217

    
218
    /* at least one es available? */
219
    while (es_map_length >= 4){
220
        unsigned char type      = avio_r8(pb);
221
        unsigned char es_id     = avio_r8(pb);
222
        uint16_t es_info_length = avio_rb16(pb);
223
        /* remember mapping from stream id to stream type */
224
        m->psm_es_type[es_id] = type;
225
        /* skip program_stream_info */
226
        url_fskip(pb, es_info_length);
227
        es_map_length -= 4 + es_info_length;
228
    }
229
    avio_rb32(pb); /* crc32 */
230
    return 2 + psm_length;
231
}
232

    
233
/* read the next PES header. Return its position in ppos
234
   (if not NULL), and its start code, pts and dts.
235
 */
236
static int mpegps_read_pes_header(AVFormatContext *s,
237
                                  int64_t *ppos, int *pstart_code,
238
                                  int64_t *ppts, int64_t *pdts)
239
{
240
    MpegDemuxContext *m = s->priv_data;
241
    int len, size, startcode, c, flags, header_len;
242
    int pes_ext, ext2_len, id_ext, skip;
243
    int64_t pts, dts;
244
    int64_t last_sync= url_ftell(s->pb);
245

    
246
 error_redo:
247
        url_fseek(s->pb, last_sync, SEEK_SET);
248
 redo:
249
        /* next start code (should be immediately after) */
250
        m->header_state = 0xff;
251
        size = MAX_SYNC_SIZE;
252
        startcode = find_next_start_code(s->pb, &size, &m->header_state);
253
        last_sync = url_ftell(s->pb);
254
    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(s->pb));
255
    if (startcode < 0){
256
        if(url_feof(s->pb))
257
            return AVERROR_EOF;
258
        //FIXME we should remember header_state
259
        return AVERROR(EAGAIN);
260
    }
261

    
262
    if (startcode == PACK_START_CODE)
263
        goto redo;
264
    if (startcode == SYSTEM_HEADER_START_CODE)
265
        goto redo;
266
    if (startcode == PADDING_STREAM) {
267
        url_fskip(s->pb, avio_rb16(s->pb));
268
        goto redo;
269
    }
270
    if (startcode == PRIVATE_STREAM_2) {
271
        len = avio_rb16(s->pb);
272
        if (!m->sofdec) {
273
            while (len-- >= 6) {
274
                if (avio_r8(s->pb) == 'S') {
275
                    uint8_t buf[5];
276
                    avio_read(s->pb, buf, sizeof(buf));
277
                    m->sofdec = !memcmp(buf, "ofdec", 5);
278
                    len -= sizeof(buf);
279
                    break;
280
                }
281
            }
282
            m->sofdec -= !m->sofdec;
283
        }
284
        url_fskip(s->pb, len);
285
        goto redo;
286
    }
287
    if (startcode == PROGRAM_STREAM_MAP) {
288
        mpegps_psm_parse(m, s->pb);
289
        goto redo;
290
    }
291

    
292
    /* find matching stream */
293
    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
294
          (startcode >= 0x1e0 && startcode <= 0x1ef) ||
295
          (startcode == 0x1bd) || (startcode == 0x1fd)))
296
        goto redo;
297
    if (ppos) {
298
        *ppos = url_ftell(s->pb) - 4;
299
    }
300
    len = avio_rb16(s->pb);
301
    pts =
302
    dts = AV_NOPTS_VALUE;
303
    /* stuffing */
304
    for(;;) {
305
        if (len < 1)
306
            goto error_redo;
307
        c = avio_r8(s->pb);
308
        len--;
309
        /* XXX: for mpeg1, should test only bit 7 */
310
        if (c != 0xff)
311
            break;
312
    }
313
    if ((c & 0xc0) == 0x40) {
314
        /* buffer scale & size */
315
        avio_r8(s->pb);
316
        c = avio_r8(s->pb);
317
        len -= 2;
318
    }
319
    if ((c & 0xe0) == 0x20) {
320
        dts = pts = get_pts(s->pb, c);
321
        len -= 4;
322
        if (c & 0x10){
323
            dts = get_pts(s->pb, -1);
324
            len -= 5;
325
        }
326
    } else if ((c & 0xc0) == 0x80) {
327
        /* mpeg 2 PES */
328
#if 0 /* some streams have this field set for no apparent reason */
329
        if ((c & 0x30) != 0) {
330
            /* Encrypted multiplex not handled */
331
            goto redo;
332
        }
333
#endif
334
        flags = avio_r8(s->pb);
335
        header_len = avio_r8(s->pb);
336
        len -= 2;
337
        if (header_len > len)
338
            goto error_redo;
339
        len -= header_len;
340
        if (flags & 0x80) {
341
            dts = pts = get_pts(s->pb, -1);
342
            header_len -= 5;
343
            if (flags & 0x40) {
344
                dts = get_pts(s->pb, -1);
345
                header_len -= 5;
346
            }
347
        }
348
        if (flags & 0x3f && header_len == 0){
349
            flags &= 0xC0;
350
            av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");
351
        }
352
        if (flags & 0x01) { /* PES extension */
353
            pes_ext = avio_r8(s->pb);
354
            header_len--;
355
            /* Skip PES private data, program packet sequence counter and P-STD buffer */
356
            skip = (pes_ext >> 4) & 0xb;
357
            skip += skip & 0x9;
358
            if (pes_ext & 0x40 || skip > header_len){
359
                av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);
360
                pes_ext=skip=0;
361
            }
362
            url_fskip(s->pb, skip);
363
            header_len -= skip;
364

    
365
            if (pes_ext & 0x01) { /* PES extension 2 */
366
                ext2_len = avio_r8(s->pb);
367
                header_len--;
368
                if ((ext2_len & 0x7f) > 0) {
369
                    id_ext = avio_r8(s->pb);
370
                    if ((id_ext & 0x80) == 0)
371
                        startcode = ((startcode & 0xff) << 8) | id_ext;
372
                    header_len--;
373
                }
374
            }
375
        }
376
        if(header_len < 0)
377
            goto error_redo;
378
        url_fskip(s->pb, header_len);
379
    }
380
    else if( c!= 0xf )
381
        goto redo;
382

    
383
    if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
384
        startcode = avio_r8(s->pb);
385
        len--;
386
        if (startcode >= 0x80 && startcode <= 0xcf) {
387
            /* audio: skip header */
388
            avio_r8(s->pb);
389
            avio_r8(s->pb);
390
            avio_r8(s->pb);
391
            len -= 3;
392
            if (startcode >= 0xb0 && startcode <= 0xbf) {
393
                /* MLP/TrueHD audio has a 4-byte header */
394
                avio_r8(s->pb);
395
                len--;
396
            }
397
        }
398
    }
399
    if(len<0)
400
        goto error_redo;
401
    if(dts != AV_NOPTS_VALUE && ppos){
402
        int i;
403
        for(i=0; i<s->nb_streams; i++){
404
            if(startcode == s->streams[i]->id &&
405
               !url_is_streamed(s->pb) /* index useless on streams anyway */) {
406
                ff_reduce_index(s, i);
407
                av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
408
            }
409
        }
410
    }
411

    
412
    *pstart_code = startcode;
413
    *ppts = pts;
414
    *pdts = dts;
415
    return len;
416
}
417

    
418
static int mpegps_read_packet(AVFormatContext *s,
419
                              AVPacket *pkt)
420
{
421
    MpegDemuxContext *m = s->priv_data;
422
    AVStream *st;
423
    int len, startcode, i, es_type;
424
    enum CodecID codec_id = CODEC_ID_NONE;
425
    enum AVMediaType type;
426
    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
427
    uint8_t av_uninit(dvdaudio_substream_type);
428

    
429
 redo:
430
    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
431
    if (len < 0)
432
        return len;
433

    
434
    if(startcode == 0x1bd) {
435
        dvdaudio_substream_type = avio_r8(s->pb);
436
        url_fskip(s->pb, 3);
437
        len -= 4;
438
    }
439

    
440
    /* now find stream */
441
    for(i=0;i<s->nb_streams;i++) {
442
        st = s->streams[i];
443
        if (st->id == startcode)
444
            goto found;
445
    }
446

    
447
    es_type = m->psm_es_type[startcode & 0xff];
448
    if(es_type > 0 && es_type != STREAM_TYPE_PRIVATE_DATA){
449
        if(es_type == STREAM_TYPE_VIDEO_MPEG1){
450
            codec_id = CODEC_ID_MPEG2VIDEO;
451
            type = AVMEDIA_TYPE_VIDEO;
452
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
453
            codec_id = CODEC_ID_MPEG2VIDEO;
454
            type = AVMEDIA_TYPE_VIDEO;
455
        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
456
                  es_type == STREAM_TYPE_AUDIO_MPEG2){
457
            codec_id = CODEC_ID_MP3;
458
            type = AVMEDIA_TYPE_AUDIO;
459
        } else if(es_type == STREAM_TYPE_AUDIO_AAC){
460
            codec_id = CODEC_ID_AAC;
461
            type = AVMEDIA_TYPE_AUDIO;
462
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
463
            codec_id = CODEC_ID_MPEG4;
464
            type = AVMEDIA_TYPE_VIDEO;
465
        } else if(es_type == STREAM_TYPE_VIDEO_H264){
466
            codec_id = CODEC_ID_H264;
467
            type = AVMEDIA_TYPE_VIDEO;
468
        } else if(es_type == STREAM_TYPE_AUDIO_AC3){
469
            codec_id = CODEC_ID_AC3;
470
            type = AVMEDIA_TYPE_AUDIO;
471
        } else {
472
            goto skip;
473
        }
474
    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
475
        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
476
        unsigned char buf[8];
477
        avio_read(s->pb, buf, 8);
478
        url_fseek(s->pb, -8, SEEK_CUR);
479
        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
480
            codec_id = CODEC_ID_CAVS;
481
        else
482
            codec_id = CODEC_ID_PROBE;
483
        type = AVMEDIA_TYPE_VIDEO;
484
    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
485
        type = AVMEDIA_TYPE_AUDIO;
486
        codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
487
    } else if (startcode >= 0x80 && startcode <= 0x87) {
488
        type = AVMEDIA_TYPE_AUDIO;
489
        codec_id = CODEC_ID_AC3;
490
    } else if (  ( startcode >= 0x88 && startcode <= 0x8f)
491
               ||( startcode >= 0x98 && startcode <= 0x9f)) {
492
        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
493
        type = AVMEDIA_TYPE_AUDIO;
494
        codec_id = CODEC_ID_DTS;
495
    } else if (startcode >= 0xa0 && startcode <= 0xaf) {
496
        type = AVMEDIA_TYPE_AUDIO;
497
        /* 16 bit form will be handled as CODEC_ID_PCM_S16BE */
498
        codec_id = CODEC_ID_PCM_DVD;
499
    } else if (startcode >= 0xb0 && startcode <= 0xbf) {
500
        type = AVMEDIA_TYPE_AUDIO;
501
        codec_id = CODEC_ID_TRUEHD;
502
    } else if (startcode >= 0xc0 && startcode <= 0xcf) {
503
        /* Used for both AC-3 and E-AC-3 in EVOB files */
504
        type = AVMEDIA_TYPE_AUDIO;
505
        codec_id = CODEC_ID_AC3;
506
    } else if (startcode >= 0x20 && startcode <= 0x3f) {
507
        type = AVMEDIA_TYPE_SUBTITLE;
508
        codec_id = CODEC_ID_DVD_SUBTITLE;
509
    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
510
        type = AVMEDIA_TYPE_VIDEO;
511
        codec_id = CODEC_ID_VC1;
512
    } else if (startcode == 0x1bd) {
513
        // check dvd audio substream type
514
        type = AVMEDIA_TYPE_AUDIO;
515
        switch(dvdaudio_substream_type & 0xe0) {
516
        case 0xa0:  codec_id = CODEC_ID_PCM_DVD;
517
                    break;
518
        case 0x80:  if((dvdaudio_substream_type & 0xf8) == 0x88)
519
                         codec_id = CODEC_ID_DTS;
520
                    else codec_id = CODEC_ID_AC3;
521
                    break;
522
        default:    av_log(s, AV_LOG_ERROR, "Unknown 0x1bd sub-stream\n");
523
                    goto skip;
524
        }
525
    } else {
526
    skip:
527
        /* skip packet */
528
        url_fskip(s->pb, len);
529
        goto redo;
530
    }
531
    /* no stream found: add a new stream */
532
    st = av_new_stream(s, startcode);
533
    if (!st)
534
        goto skip;
535
    st->codec->codec_type = type;
536
    st->codec->codec_id = codec_id;
537
    if (codec_id != CODEC_ID_PCM_S16BE)
538
        st->need_parsing = AVSTREAM_PARSE_FULL;
539
 found:
540
    if(st->discard >= AVDISCARD_ALL)
541
        goto skip;
542
    if ((startcode >= 0xa0 && startcode <= 0xaf) ||
543
        (startcode == 0x1bd && ((dvdaudio_substream_type & 0xe0) == 0xa0))) {
544
        int b1, freq;
545

    
546
        /* for LPCM, we just skip the header and consider it is raw
547
           audio data */
548
        if (len <= 3)
549
            goto skip;
550
        avio_r8(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
551
        b1 = avio_r8(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
552
        avio_r8(s->pb); /* dynamic range control (0x80 = off) */
553
        len -= 3;
554
        freq = (b1 >> 4) & 3;
555
        st->codec->sample_rate = lpcm_freq_tab[freq];
556
        st->codec->channels = 1 + (b1 & 7);
557
        st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;
558
        st->codec->bit_rate = st->codec->channels *
559
                              st->codec->sample_rate *
560
                              st->codec->bits_per_coded_sample;
561
        if (st->codec->bits_per_coded_sample == 16)
562
            st->codec->codec_id = CODEC_ID_PCM_S16BE;
563
        else if (st->codec->bits_per_coded_sample == 28)
564
            return AVERROR(EINVAL);
565
    }
566
    av_new_packet(pkt, len);
567
    avio_read(s->pb, pkt->data, pkt->size);
568
    pkt->pts = pts;
569
    pkt->dts = dts;
570
    pkt->pos = dummy_pos;
571
    pkt->stream_index = st->index;
572
#if 0
573
    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
574
           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
575
#endif
576

    
577
    return 0;
578
}
579

    
580
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
581
                               int64_t *ppos, int64_t pos_limit)
582
{
583
    int len, startcode;
584
    int64_t pos, pts, dts;
585

    
586
    pos = *ppos;
587
#ifdef DEBUG_SEEK
588
    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
589
#endif
590
    if (url_fseek(s->pb, pos, SEEK_SET) < 0)
591
        return AV_NOPTS_VALUE;
592

    
593
    for(;;) {
594
        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
595
        if (len < 0) {
596
#ifdef DEBUG_SEEK
597
            printf("none (ret=%d)\n", len);
598
#endif
599
            return AV_NOPTS_VALUE;
600
        }
601
        if (startcode == s->streams[stream_index]->id &&
602
            dts != AV_NOPTS_VALUE) {
603
            break;
604
        }
605
        url_fskip(s->pb, len);
606
    }
607
#ifdef DEBUG_SEEK
608
    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
609
#endif
610
    *ppos = pos;
611
    return dts;
612
}
613

    
614
AVInputFormat ff_mpegps_demuxer = {
615
    "mpeg",
616
    NULL_IF_CONFIG_SMALL("MPEG-PS format"),
617
    sizeof(MpegDemuxContext),
618
    mpegps_probe,
619
    mpegps_read_header,
620
    mpegps_read_packet,
621
    NULL,
622
    NULL, //mpegps_read_seek,
623
    mpegps_read_dts,
624
    .flags = AVFMT_SHOW_IDS|AVFMT_TS_DISCONT,
625
};