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ffmpeg / libavformat / mpeg.c @ 8cd4ac3d

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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 cdxa_probe(AVProbeData *p)
36
{
37
    /* check file header */
38
    if (p->buf[0] == 'R' && p->buf[1] == 'I' &&
39
        p->buf[2] == 'F' && p->buf[3] == 'F' &&
40
        p->buf[8] == 'C' && p->buf[9] == 'D' &&
41
        p->buf[10] == 'X' && p->buf[11] == 'A')
42
        return AVPROBE_SCORE_MAX;
43
    else
44
        return 0;
45
}
46

    
47
static int check_pes(uint8_t *p, uint8_t *end){
48
    int pes1;
49
    int pes2=      (p[3] & 0xC0) == 0x80
50
                && (p[4] & 0xC0) != 0x40
51
                &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));
52

    
53
    for(p+=3; p<end && *p == 0xFF; p++);
54
    if((*p&0xC0) == 0x40) p+=2;
55
    if((*p&0xF0) == 0x20){
56
        pes1= p[0]&p[2]&p[4]&1;
57
        p+=5;
58
    }else if((*p&0xF0) == 0x30){
59
        pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
60
        p+=10;
61
    }else
62
        pes1 = *p == 0x0F;
63

    
64
    return pes1||pes2;
65
}
66

    
67
static int mpegps_probe(AVProbeData *p)
68
{
69
    uint32_t code= -1;
70
    int sys=0, pspack=0, priv1=0, vid=0, audio=0;
71
    int i;
72
    int score=0;
73

    
74
    score = cdxa_probe(p);
75
    if (score > 0) return score;
76

    
77
    /* Search for MPEG stream */
78
    for(i=0; i<p->buf_size; i++){
79
        code = (code<<8) + p->buf[i];
80
        if ((code & 0xffffff00) == 0x100) {
81
            int pes= check_pes(p->buf+i, p->buf+p->buf_size);
82

    
83
            if(code == SYSTEM_HEADER_START_CODE) sys++;
84
            else if(code == PRIVATE_STREAM_1)    priv1++;
85
            else if(code == PACK_START_CODE)     pspack++;
86
            else if((code & 0xf0) == VIDEO_ID && pes) vid++;
87
            else if((code & 0xe0) == AUDIO_ID && pes) audio++;
88
        }
89
    }
90

    
91
    if(vid || audio)            /* invalid VDR files nd short PES streams */
92
        score= AVPROBE_SCORE_MAX/4;
93

    
94
//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, p->buf_size);
95
    if(sys && sys*9 <= pspack*10)
96
        return AVPROBE_SCORE_MAX/2+2; // +1 for .mpg
97
    if((priv1 || vid || audio) && (priv1+vid+audio)*9 <= pspack*10)
98
        return AVPROBE_SCORE_MAX/2+2; // +1 for .mpg
99
    if((!!vid ^ !!audio) && (audio+vid > 1) && !sys && !pspack && p->buf_size>2048) /* PES stream */
100
        return AVPROBE_SCORE_MAX/2+2;
101

    
102
    //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
103
    return score;
104
}
105

    
106

    
107
typedef struct MpegDemuxContext {
108
    int32_t header_state;
109
    unsigned char psm_es_type[256];
110
    int sofdec;
111
} MpegDemuxContext;
112

    
113
static int mpegps_read_header(AVFormatContext *s,
114
                              AVFormatParameters *ap)
115
{
116
    MpegDemuxContext *m = s->priv_data;
117
    uint8_t buffer[8192];
118
    char *p;
119

    
120
    m->header_state = 0xff;
121
    s->ctx_flags |= AVFMTCTX_NOHEADER;
122

    
123
    get_buffer(&s->pb, buffer, sizeof(buffer));
124
    if ((p=memchr(buffer, 'S', sizeof(buffer))))
125
        if (!memcmp(p, "Sofdec", 6))
126
            m->sofdec = 1;
127
    url_fseek(&s->pb, -sizeof(buffer), SEEK_CUR);
128

    
129
    /* no need to do more */
130
    return 0;
131
}
132

    
133
static int64_t get_pts(ByteIOContext *pb, int c)
134
{
135
    int64_t pts;
136
    int val;
137

    
138
    if (c < 0)
139
        c = get_byte(pb);
140
    pts = (int64_t)((c >> 1) & 0x07) << 30;
141
    val = get_be16(pb);
142
    pts |= (int64_t)(val >> 1) << 15;
143
    val = get_be16(pb);
144
    pts |= (int64_t)(val >> 1);
145
    return pts;
146
}
147

    
148
static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
149
                                int32_t *header_state)
150
{
151
    unsigned int state, v;
152
    int val, n;
153

    
154
    state = *header_state;
155
    n = *size_ptr;
156
    while (n > 0) {
157
        if (url_feof(pb))
158
            break;
159
        v = get_byte(pb);
160
        n--;
161
        if (state == 0x000001) {
162
            state = ((state << 8) | v) & 0xffffff;
163
            val = state;
164
            goto found;
165
        }
166
        state = ((state << 8) | v) & 0xffffff;
167
    }
168
    val = -1;
169
 found:
170
    *header_state = state;
171
    *size_ptr = n;
172
    return val;
173
}
174

    
175
#if 0 /* unused, remove? */
176
/* XXX: optimize */
177
static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
178
{
179
    int64_t pos, pos_start;
180
    int max_size, start_code;
181

182
    max_size = *size_ptr;
183
    pos_start = url_ftell(pb);
184

185
    /* in order to go faster, we fill the buffer */
186
    pos = pos_start - 16386;
187
    if (pos < 0)
188
        pos = 0;
189
    url_fseek(pb, pos, SEEK_SET);
190
    get_byte(pb);
191

192
    pos = pos_start;
193
    for(;;) {
194
        pos--;
195
        if (pos < 0 || (pos_start - pos) >= max_size) {
196
            start_code = -1;
197
            goto the_end;
198
        }
199
        url_fseek(pb, pos, SEEK_SET);
200
        start_code = get_be32(pb);
201
        if ((start_code & 0xffffff00) == 0x100)
202
            break;
203
    }
204
 the_end:
205
    *size_ptr = pos_start - pos;
206
    return start_code;
207
}
208
#endif
209

    
210
/**
211
 * Extracts stream types from a program stream map
212
 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
213
 *
214
 * @return number of bytes occupied by PSM in the bitstream
215
 */
216
static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
217
{
218
    int psm_length, ps_info_length, es_map_length;
219

    
220
    psm_length = get_be16(pb);
221
    get_byte(pb);
222
    get_byte(pb);
223
    ps_info_length = get_be16(pb);
224

    
225
    /* skip program_stream_info */
226
    url_fskip(pb, ps_info_length);
227
    es_map_length = get_be16(pb);
228

    
229
    /* at least one es available? */
230
    while (es_map_length >= 4){
231
        unsigned char type = get_byte(pb);
232
        unsigned char es_id = get_byte(pb);
233
        uint16_t es_info_length = get_be16(pb);
234
        /* remember mapping from stream id to stream type */
235
        m->psm_es_type[es_id] = type;
236
        /* skip program_stream_info */
237
        url_fskip(pb, es_info_length);
238
        es_map_length -= 4 + es_info_length;
239
    }
240
    get_be32(pb); /* crc32 */
241
    return 2 + psm_length;
242
}
243

    
244
/* read the next PES header. Return its position in ppos
245
   (if not NULL), and its start code, pts and dts.
246
 */
247
static int mpegps_read_pes_header(AVFormatContext *s,
248
                                  int64_t *ppos, int *pstart_code,
249
                                  int64_t *ppts, int64_t *pdts)
250
{
251
    MpegDemuxContext *m = s->priv_data;
252
    int len, size, startcode, c, flags, header_len;
253
    int pes_ext, ext2_len, id_ext, skip;
254
    int64_t pts, dts;
255
    int64_t last_sync= url_ftell(&s->pb);
256

    
257
 error_redo:
258
        url_fseek(&s->pb, last_sync, SEEK_SET);
259
 redo:
260
        /* next start code (should be immediately after) */
261
        m->header_state = 0xff;
262
        size = MAX_SYNC_SIZE;
263
        startcode = find_next_start_code(&s->pb, &size, &m->header_state);
264
        last_sync = url_ftell(&s->pb);
265
    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(&s->pb));
266
    if (startcode < 0)
267
        return AVERROR(EIO);
268
    if (startcode == PACK_START_CODE)
269
        goto redo;
270
    if (startcode == SYSTEM_HEADER_START_CODE)
271
        goto redo;
272
    if (startcode == PADDING_STREAM ||
273
        startcode == PRIVATE_STREAM_2) {
274
        /* skip them */
275
        len = get_be16(&s->pb);
276
        url_fskip(&s->pb, len);
277
        goto redo;
278
    }
279
    if (startcode == PROGRAM_STREAM_MAP) {
280
        mpegps_psm_parse(m, &s->pb);
281
        goto redo;
282
    }
283

    
284
    /* find matching stream */
285
    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
286
          (startcode >= 0x1e0 && startcode <= 0x1ef) ||
287
          (startcode == 0x1bd) || (startcode == 0x1fd)))
288
        goto redo;
289
    if (ppos) {
290
        *ppos = url_ftell(&s->pb) - 4;
291
    }
292
    len = get_be16(&s->pb);
293
    pts =
294
    dts = AV_NOPTS_VALUE;
295
    /* stuffing */
296
    for(;;) {
297
        if (len < 1)
298
            goto error_redo;
299
        c = get_byte(&s->pb);
300
        len--;
301
        /* XXX: for mpeg1, should test only bit 7 */
302
        if (c != 0xff)
303
            break;
304
    }
305
    if ((c & 0xc0) == 0x40) {
306
        /* buffer scale & size */
307
        get_byte(&s->pb);
308
        c = get_byte(&s->pb);
309
        len -= 2;
310
    }
311
    if ((c & 0xe0) == 0x20) {
312
        dts = pts = get_pts(&s->pb, c);
313
        len -= 4;
314
        if (c & 0x10){
315
            dts = get_pts(&s->pb, -1);
316
            len -= 5;
317
        }
318
    } else if ((c & 0xc0) == 0x80) {
319
        /* mpeg 2 PES */
320
#if 0 /* some streams have this field set for no apparent reason */
321
        if ((c & 0x30) != 0) {
322
            /* Encrypted multiplex not handled */
323
            goto redo;
324
        }
325
#endif
326
        flags = get_byte(&s->pb);
327
        header_len = get_byte(&s->pb);
328
        len -= 2;
329
        if (header_len > len)
330
            goto error_redo;
331
        len -= header_len;
332
        if (flags & 0x80) {
333
            dts = pts = get_pts(&s->pb, -1);
334
            header_len -= 5;
335
            if (flags & 0x40) {
336
                dts = get_pts(&s->pb, -1);
337
                header_len -= 5;
338
            }
339
        }
340
        if (flags & 0x01) { /* PES extension */
341
            pes_ext = get_byte(&s->pb);
342
            header_len--;
343
            if (pes_ext & 0x40) { /* pack header - should be zero in PS */
344
                goto error_redo;
345
            }
346
            /* Skip PES private data, program packet sequence counter and P-STD buffer */
347
            skip = (pes_ext >> 4) & 0xb;
348
            skip += skip & 0x9;
349
            url_fskip(&s->pb, skip);
350
            header_len -= skip;
351

    
352
            if (pes_ext & 0x01) { /* PES extension 2 */
353
                ext2_len = get_byte(&s->pb);
354
                header_len--;
355
                if ((ext2_len & 0x7f) > 0) {
356
                    id_ext = get_byte(&s->pb);
357
                    if ((id_ext & 0x80) == 0)
358
                        startcode = ((startcode & 0xff) << 8) | id_ext;
359
                    header_len--;
360
                }
361
            }
362
        }
363
        if(header_len < 0)
364
            goto error_redo;
365
        url_fskip(&s->pb, header_len);
366
    }
367
    else if( c!= 0xf )
368
        goto redo;
369

    
370
    if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
371
        startcode = get_byte(&s->pb);
372
        len--;
373
        if (startcode >= 0x80 && startcode <= 0xcf) {
374
            /* audio: skip header */
375
            get_byte(&s->pb);
376
            get_byte(&s->pb);
377
            get_byte(&s->pb);
378
            len -= 3;
379
            if (startcode >= 0xb0 && startcode <= 0xbf) {
380
                /* MLP/TrueHD audio has a 4-byte header */
381
                get_byte(&s->pb);
382
                len--;
383
            }
384
        }
385
    }
386
    if(len<0)
387
        goto error_redo;
388
    if(dts != AV_NOPTS_VALUE && ppos){
389
        int i;
390
        for(i=0; i<s->nb_streams; i++){
391
            if(startcode == s->streams[i]->id) {
392
                av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
393
            }
394
        }
395
    }
396

    
397
    *pstart_code = startcode;
398
    *ppts = pts;
399
    *pdts = dts;
400
    return len;
401
}
402

    
403
static int mpegps_read_packet(AVFormatContext *s,
404
                              AVPacket *pkt)
405
{
406
    MpegDemuxContext *m = s->priv_data;
407
    AVStream *st;
408
    int len, startcode, i, type, codec_id = 0, es_type;
409
    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
410

    
411
 redo:
412
    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
413
    if (len < 0)
414
        return len;
415

    
416
    /* now find stream */
417
    for(i=0;i<s->nb_streams;i++) {
418
        st = s->streams[i];
419
        if (st->id == startcode)
420
            goto found;
421
    }
422

    
423
    es_type = m->psm_es_type[startcode & 0xff];
424
    if(es_type > 0){
425
        if(es_type == STREAM_TYPE_VIDEO_MPEG1){
426
            codec_id = CODEC_ID_MPEG2VIDEO;
427
            type = CODEC_TYPE_VIDEO;
428
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
429
            codec_id = CODEC_ID_MPEG2VIDEO;
430
            type = CODEC_TYPE_VIDEO;
431
        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
432
                  es_type == STREAM_TYPE_AUDIO_MPEG2){
433
            codec_id = CODEC_ID_MP3;
434
            type = CODEC_TYPE_AUDIO;
435
        } else if(es_type == STREAM_TYPE_AUDIO_AAC){
436
            codec_id = CODEC_ID_AAC;
437
            type = CODEC_TYPE_AUDIO;
438
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
439
            codec_id = CODEC_ID_MPEG4;
440
            type = CODEC_TYPE_VIDEO;
441
        } else if(es_type == STREAM_TYPE_VIDEO_H264){
442
            codec_id = CODEC_ID_H264;
443
            type = CODEC_TYPE_VIDEO;
444
        } else if(es_type == STREAM_TYPE_AUDIO_AC3){
445
            codec_id = CODEC_ID_AC3;
446
            type = CODEC_TYPE_AUDIO;
447
        } else {
448
            goto skip;
449
        }
450
    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
451
        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
452
        unsigned char buf[8];
453
        get_buffer(&s->pb, buf, 8);
454
        url_fseek(&s->pb, -8, SEEK_CUR);
455
        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
456
            codec_id = CODEC_ID_CAVS;
457
        else
458
            codec_id = CODEC_ID_MPEG2VIDEO;
459
        type = CODEC_TYPE_VIDEO;
460
    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
461
        type = CODEC_TYPE_AUDIO;
462
        codec_id = m->sofdec ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
463
    } else if (startcode >= 0x80 && startcode <= 0x87) {
464
        type = CODEC_TYPE_AUDIO;
465
        codec_id = CODEC_ID_AC3;
466
    } else if ((startcode >= 0x88 && startcode <= 0x8f)
467
               ||( startcode >= 0x98 && startcode <= 0x9f)) {
468
        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
469
        type = CODEC_TYPE_AUDIO;
470
        codec_id = CODEC_ID_DTS;
471
    } else if (startcode >= 0xa0 && startcode <= 0xaf) {
472
        type = CODEC_TYPE_AUDIO;
473
        codec_id = CODEC_ID_PCM_S16BE;
474
    } else if (startcode >= 0xb0 && startcode <= 0xbf) {
475
        type = CODEC_TYPE_AUDIO;
476
        codec_id = CODEC_ID_MLP;
477
    } else if (startcode >= 0xc0 && startcode <= 0xcf) {
478
        /* Used for both AC-3 and E-AC-3 in EVOB files */
479
        type = CODEC_TYPE_AUDIO;
480
        codec_id = CODEC_ID_AC3;
481
    } else if (startcode >= 0x20 && startcode <= 0x3f) {
482
        type = CODEC_TYPE_SUBTITLE;
483
        codec_id = CODEC_ID_DVD_SUBTITLE;
484
    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
485
        type = CODEC_TYPE_VIDEO;
486
        codec_id = CODEC_ID_VC1;
487
    } else {
488
    skip:
489
        /* skip packet */
490
        url_fskip(&s->pb, len);
491
        goto redo;
492
    }
493
    /* no stream found: add a new stream */
494
    st = av_new_stream(s, startcode);
495
    if (!st)
496
        goto skip;
497
    st->codec->codec_type = type;
498
    st->codec->codec_id = codec_id;
499
    if (codec_id != CODEC_ID_PCM_S16BE)
500
        st->need_parsing = AVSTREAM_PARSE_FULL;
501
 found:
502
    if(st->discard >= AVDISCARD_ALL)
503
        goto skip;
504
    if (startcode >= 0xa0 && startcode <= 0xaf) {
505
        int b1, freq;
506

    
507
        /* for LPCM, we just skip the header and consider it is raw
508
           audio data */
509
        if (len <= 3)
510
            goto skip;
511
        get_byte(&s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
512
        b1 = get_byte(&s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
513
        get_byte(&s->pb); /* dynamic range control (0x80 = off) */
514
        len -= 3;
515
        freq = (b1 >> 4) & 3;
516
        st->codec->sample_rate = lpcm_freq_tab[freq];
517
        st->codec->channels = 1 + (b1 & 7);
518
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate * 2;
519
    }
520
    av_new_packet(pkt, len);
521
    get_buffer(&s->pb, pkt->data, pkt->size);
522
    pkt->pts = pts;
523
    pkt->dts = dts;
524
    pkt->stream_index = st->index;
525
#if 0
526
    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
527
           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
528
#endif
529

    
530
    return 0;
531
}
532

    
533
static int mpegps_read_close(AVFormatContext *s)
534
{
535
    return 0;
536
}
537

    
538
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
539
                               int64_t *ppos, int64_t pos_limit)
540
{
541
    int len, startcode;
542
    int64_t pos, pts, dts;
543

    
544
    pos = *ppos;
545
#ifdef DEBUG_SEEK
546
    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
547
#endif
548
    url_fseek(&s->pb, pos, SEEK_SET);
549
    for(;;) {
550
        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
551
        if (len < 0) {
552
#ifdef DEBUG_SEEK
553
            printf("none (ret=%d)\n", len);
554
#endif
555
            return AV_NOPTS_VALUE;
556
        }
557
        if (startcode == s->streams[stream_index]->id &&
558
            dts != AV_NOPTS_VALUE) {
559
            break;
560
        }
561
        url_fskip(&s->pb, len);
562
    }
563
#ifdef DEBUG_SEEK
564
    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
565
#endif
566
    *ppos = pos;
567
    return dts;
568
}
569

    
570
AVInputFormat mpegps_demuxer = {
571
    "mpeg",
572
    "MPEG PS format",
573
    sizeof(MpegDemuxContext),
574
    mpegps_probe,
575
    mpegps_read_header,
576
    mpegps_read_packet,
577
    mpegps_read_close,
578
    NULL, //mpegps_read_seek,
579
    mpegps_read_dts,
580
    .flags = AVFMT_SHOW_IDS,
581
};