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ffmpeg / libavformat / mpeg.c @ 890d2799

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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
    const char *sofdec = "Sofdec";
118
    int v, i = 0;
119

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

    
123
    m->sofdec = -1;
124
    do {
125
        v = get_byte(s->pb);
126
        m->header_state = m->header_state << 8 | v;
127
        m->sofdec++;
128
    } while (v == sofdec[i] && i++ < 6);
129

    
130
    /* no need to do more */
131
    return 0;
132
}
133

    
134
static int64_t get_pts(ByteIOContext *pb, int c)
135
{
136
    int64_t pts;
137
    int val;
138

    
139
    if (c < 0)
140
        c = get_byte(pb);
141
    pts = (int64_t)((c >> 1) & 0x07) << 30;
142
    val = get_be16(pb);
143
    pts |= (int64_t)(val >> 1) << 15;
144
    val = get_be16(pb);
145
    pts |= (int64_t)(val >> 1);
146
    return pts;
147
}
148

    
149
static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
150
                                int32_t *header_state)
151
{
152
    unsigned int state, v;
153
    int val, n;
154

    
155
    state = *header_state;
156
    n = *size_ptr;
157
    while (n > 0) {
158
        if (url_feof(pb))
159
            break;
160
        v = get_byte(pb);
161
        n--;
162
        if (state == 0x000001) {
163
            state = ((state << 8) | v) & 0xffffff;
164
            val = state;
165
            goto found;
166
        }
167
        state = ((state << 8) | v) & 0xffffff;
168
    }
169
    val = -1;
170
 found:
171
    *header_state = state;
172
    *size_ptr = n;
173
    return val;
174
}
175

    
176
#if 0 /* unused, remove? */
177
/* XXX: optimize */
178
static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
179
{
180
    int64_t pos, pos_start;
181
    int max_size, start_code;
182

183
    max_size = *size_ptr;
184
    pos_start = url_ftell(pb);
185

186
    /* in order to go faster, we fill the buffer */
187
    pos = pos_start - 16386;
188
    if (pos < 0)
189
        pos = 0;
190
    url_fseek(pb, pos, SEEK_SET);
191
    get_byte(pb);
192

193
    pos = pos_start;
194
    for(;;) {
195
        pos--;
196
        if (pos < 0 || (pos_start - pos) >= max_size) {
197
            start_code = -1;
198
            goto the_end;
199
        }
200
        url_fseek(pb, pos, SEEK_SET);
201
        start_code = get_be32(pb);
202
        if ((start_code & 0xffffff00) == 0x100)
203
            break;
204
    }
205
 the_end:
206
    *size_ptr = pos_start - pos;
207
    return start_code;
208
}
209
#endif
210

    
211
/**
212
 * Extracts stream types from a program stream map
213
 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
214
 *
215
 * @return number of bytes occupied by PSM in the bitstream
216
 */
217
static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
218
{
219
    int psm_length, ps_info_length, es_map_length;
220

    
221
    psm_length = get_be16(pb);
222
    get_byte(pb);
223
    get_byte(pb);
224
    ps_info_length = get_be16(pb);
225

    
226
    /* skip program_stream_info */
227
    url_fskip(pb, ps_info_length);
228
    es_map_length = get_be16(pb);
229

    
230
    /* at least one es available? */
231
    while (es_map_length >= 4){
232
        unsigned char type = get_byte(pb);
233
        unsigned char es_id = get_byte(pb);
234
        uint16_t es_info_length = get_be16(pb);
235
        /* remember mapping from stream id to stream type */
236
        m->psm_es_type[es_id] = type;
237
        /* skip program_stream_info */
238
        url_fskip(pb, es_info_length);
239
        es_map_length -= 4 + es_info_length;
240
    }
241
    get_be32(pb); /* crc32 */
242
    return 2 + psm_length;
243
}
244

    
245
/* read the next PES header. Return its position in ppos
246
   (if not NULL), and its start code, pts and dts.
247
 */
248
static int mpegps_read_pes_header(AVFormatContext *s,
249
                                  int64_t *ppos, int *pstart_code,
250
                                  int64_t *ppts, int64_t *pdts)
251
{
252
    MpegDemuxContext *m = s->priv_data;
253
    int len, size, startcode, c, flags, header_len;
254
    int pes_ext, ext2_len, id_ext, skip;
255
    int64_t pts, dts;
256
    int64_t last_sync= url_ftell(s->pb);
257

    
258
 error_redo:
259
        url_fseek(s->pb, last_sync, SEEK_SET);
260
 redo:
261
        /* next start code (should be immediately after) */
262
        m->header_state = 0xff;
263
        size = MAX_SYNC_SIZE;
264
        startcode = find_next_start_code(s->pb, &size, &m->header_state);
265
        last_sync = url_ftell(s->pb);
266
    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(s->pb));
267
    if (startcode < 0)
268
        return AVERROR(EIO);
269
    if (startcode == PACK_START_CODE)
270
        goto redo;
271
    if (startcode == SYSTEM_HEADER_START_CODE)
272
        goto redo;
273
    if (startcode == PADDING_STREAM) {
274
        url_fskip(s->pb, get_be16(s->pb));
275
        goto redo;
276
    }
277
    if (startcode == PRIVATE_STREAM_2) {
278
        len = get_be16(s->pb);
279
        if (!m->sofdec) {
280
            while (len-- >= 6) {
281
                if (get_byte(s->pb) == 'S') {
282
                    uint8_t buf[5];
283
                    get_buffer(s->pb, buf, sizeof(buf));
284
                    m->sofdec = !memcmp(buf, "ofdec", 5);
285
                    len -= sizeof(buf);
286
                    break;
287
                }
288
            }
289
            m->sofdec -= !m->sofdec;
290
        }
291
        url_fskip(s->pb, len);
292
        goto redo;
293
    }
294
    if (startcode == PROGRAM_STREAM_MAP) {
295
        mpegps_psm_parse(m, s->pb);
296
        goto redo;
297
    }
298

    
299
    /* find matching stream */
300
    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
301
          (startcode >= 0x1e0 && startcode <= 0x1ef) ||
302
          (startcode == 0x1bd) || (startcode == 0x1fd)))
303
        goto redo;
304
    if (ppos) {
305
        *ppos = url_ftell(s->pb) - 4;
306
    }
307
    len = get_be16(s->pb);
308
    pts =
309
    dts = AV_NOPTS_VALUE;
310
    /* stuffing */
311
    for(;;) {
312
        if (len < 1)
313
            goto error_redo;
314
        c = get_byte(s->pb);
315
        len--;
316
        /* XXX: for mpeg1, should test only bit 7 */
317
        if (c != 0xff)
318
            break;
319
    }
320
    if ((c & 0xc0) == 0x40) {
321
        /* buffer scale & size */
322
        get_byte(s->pb);
323
        c = get_byte(s->pb);
324
        len -= 2;
325
    }
326
    if ((c & 0xe0) == 0x20) {
327
        dts = pts = get_pts(s->pb, c);
328
        len -= 4;
329
        if (c & 0x10){
330
            dts = get_pts(s->pb, -1);
331
            len -= 5;
332
        }
333
    } else if ((c & 0xc0) == 0x80) {
334
        /* mpeg 2 PES */
335
#if 0 /* some streams have this field set for no apparent reason */
336
        if ((c & 0x30) != 0) {
337
            /* Encrypted multiplex not handled */
338
            goto redo;
339
        }
340
#endif
341
        flags = get_byte(s->pb);
342
        header_len = get_byte(s->pb);
343
        len -= 2;
344
        if (header_len > len)
345
            goto error_redo;
346
        len -= header_len;
347
        if (flags & 0x80) {
348
            dts = pts = get_pts(s->pb, -1);
349
            header_len -= 5;
350
            if (flags & 0x40) {
351
                dts = get_pts(s->pb, -1);
352
                header_len -= 5;
353
            }
354
        }
355
        if (flags & 0x01) { /* PES extension */
356
            pes_ext = get_byte(s->pb);
357
            header_len--;
358
            if (pes_ext & 0x40) { /* pack header - should be zero in PS */
359
                goto error_redo;
360
            }
361
            /* Skip PES private data, program packet sequence counter and P-STD buffer */
362
            skip = (pes_ext >> 4) & 0xb;
363
            skip += skip & 0x9;
364
            url_fskip(s->pb, skip);
365
            header_len -= skip;
366

    
367
            if (pes_ext & 0x01) { /* PES extension 2 */
368
                ext2_len = get_byte(s->pb);
369
                header_len--;
370
                if ((ext2_len & 0x7f) > 0) {
371
                    id_ext = get_byte(s->pb);
372
                    if ((id_ext & 0x80) == 0)
373
                        startcode = ((startcode & 0xff) << 8) | id_ext;
374
                    header_len--;
375
                }
376
            }
377
        }
378
        if(header_len < 0)
379
            goto error_redo;
380
        url_fskip(s->pb, header_len);
381
    }
382
    else if( c!= 0xf )
383
        goto redo;
384

    
385
    if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
386
        startcode = get_byte(s->pb);
387
        len--;
388
        if (startcode >= 0x80 && startcode <= 0xcf) {
389
            /* audio: skip header */
390
            get_byte(s->pb);
391
            get_byte(s->pb);
392
            get_byte(s->pb);
393
            len -= 3;
394
            if (startcode >= 0xb0 && startcode <= 0xbf) {
395
                /* MLP/TrueHD audio has a 4-byte header */
396
                get_byte(s->pb);
397
                len--;
398
            }
399
        }
400
    }
401
    if(len<0)
402
        goto error_redo;
403
    if(dts != AV_NOPTS_VALUE && ppos){
404
        int i;
405
        for(i=0; i<s->nb_streams; i++){
406
            if(startcode == s->streams[i]->id) {
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, type, codec_id = 0, es_type;
424
    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
425

    
426
 redo:
427
    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
428
    if (len < 0)
429
        return len;
430

    
431
    /* now find stream */
432
    for(i=0;i<s->nb_streams;i++) {
433
        st = s->streams[i];
434
        if (st->id == startcode)
435
            goto found;
436
    }
437

    
438
    es_type = m->psm_es_type[startcode & 0xff];
439
    if(es_type > 0){
440
        if(es_type == STREAM_TYPE_VIDEO_MPEG1){
441
            codec_id = CODEC_ID_MPEG2VIDEO;
442
            type = CODEC_TYPE_VIDEO;
443
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
444
            codec_id = CODEC_ID_MPEG2VIDEO;
445
            type = CODEC_TYPE_VIDEO;
446
        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
447
                  es_type == STREAM_TYPE_AUDIO_MPEG2){
448
            codec_id = CODEC_ID_MP3;
449
            type = CODEC_TYPE_AUDIO;
450
        } else if(es_type == STREAM_TYPE_AUDIO_AAC){
451
            codec_id = CODEC_ID_AAC;
452
            type = CODEC_TYPE_AUDIO;
453
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
454
            codec_id = CODEC_ID_MPEG4;
455
            type = CODEC_TYPE_VIDEO;
456
        } else if(es_type == STREAM_TYPE_VIDEO_H264){
457
            codec_id = CODEC_ID_H264;
458
            type = CODEC_TYPE_VIDEO;
459
        } else if(es_type == STREAM_TYPE_AUDIO_AC3){
460
            codec_id = CODEC_ID_AC3;
461
            type = CODEC_TYPE_AUDIO;
462
        } else {
463
            goto skip;
464
        }
465
    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
466
        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
467
        unsigned char buf[8];
468
        get_buffer(s->pb, buf, 8);
469
        url_fseek(s->pb, -8, SEEK_CUR);
470
        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
471
            codec_id = CODEC_ID_CAVS;
472
        else
473
            codec_id = CODEC_ID_MPEG2VIDEO;
474
        type = CODEC_TYPE_VIDEO;
475
    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
476
        type = CODEC_TYPE_AUDIO;
477
        codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
478
    } else if (startcode >= 0x80 && startcode <= 0x87) {
479
        type = CODEC_TYPE_AUDIO;
480
        codec_id = CODEC_ID_AC3;
481
    } else if ((startcode >= 0x88 && startcode <= 0x8f)
482
               ||( startcode >= 0x98 && startcode <= 0x9f)) {
483
        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
484
        type = CODEC_TYPE_AUDIO;
485
        codec_id = CODEC_ID_DTS;
486
    } else if (startcode >= 0xa0 && startcode <= 0xaf) {
487
        type = CODEC_TYPE_AUDIO;
488
        codec_id = CODEC_ID_PCM_S16BE;
489
    } else if (startcode >= 0xb0 && startcode <= 0xbf) {
490
        type = CODEC_TYPE_AUDIO;
491
        codec_id = CODEC_ID_MLP;
492
    } else if (startcode >= 0xc0 && startcode <= 0xcf) {
493
        /* Used for both AC-3 and E-AC-3 in EVOB files */
494
        type = CODEC_TYPE_AUDIO;
495
        codec_id = CODEC_ID_AC3;
496
    } else if (startcode >= 0x20 && startcode <= 0x3f) {
497
        type = CODEC_TYPE_SUBTITLE;
498
        codec_id = CODEC_ID_DVD_SUBTITLE;
499
    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
500
        type = CODEC_TYPE_VIDEO;
501
        codec_id = CODEC_ID_VC1;
502
    } else {
503
    skip:
504
        /* skip packet */
505
        url_fskip(s->pb, len);
506
        goto redo;
507
    }
508
    /* no stream found: add a new stream */
509
    st = av_new_stream(s, startcode);
510
    if (!st)
511
        goto skip;
512
    st->codec->codec_type = type;
513
    st->codec->codec_id = codec_id;
514
    if (codec_id != CODEC_ID_PCM_S16BE)
515
        st->need_parsing = AVSTREAM_PARSE_FULL;
516
 found:
517
    if(st->discard >= AVDISCARD_ALL)
518
        goto skip;
519
    if (startcode >= 0xa0 && startcode <= 0xaf) {
520
        int b1, freq;
521

    
522
        /* for LPCM, we just skip the header and consider it is raw
523
           audio data */
524
        if (len <= 3)
525
            goto skip;
526
        get_byte(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
527
        b1 = get_byte(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
528
        get_byte(s->pb); /* dynamic range control (0x80 = off) */
529
        len -= 3;
530
        freq = (b1 >> 4) & 3;
531
        st->codec->sample_rate = lpcm_freq_tab[freq];
532
        st->codec->channels = 1 + (b1 & 7);
533
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate * 2;
534
    }
535
    av_new_packet(pkt, len);
536
    get_buffer(s->pb, pkt->data, pkt->size);
537
    pkt->pts = pts;
538
    pkt->dts = dts;
539
    pkt->stream_index = st->index;
540
#if 0
541
    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
542
           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
543
#endif
544

    
545
    return 0;
546
}
547

    
548
static int mpegps_read_close(AVFormatContext *s)
549
{
550
    return 0;
551
}
552

    
553
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
554
                               int64_t *ppos, int64_t pos_limit)
555
{
556
    int len, startcode;
557
    int64_t pos, pts, dts;
558

    
559
    pos = *ppos;
560
#ifdef DEBUG_SEEK
561
    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
562
#endif
563
    url_fseek(s->pb, pos, SEEK_SET);
564
    for(;;) {
565
        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
566
        if (len < 0) {
567
#ifdef DEBUG_SEEK
568
            printf("none (ret=%d)\n", len);
569
#endif
570
            return AV_NOPTS_VALUE;
571
        }
572
        if (startcode == s->streams[stream_index]->id &&
573
            dts != AV_NOPTS_VALUE) {
574
            break;
575
        }
576
        url_fskip(s->pb, len);
577
    }
578
#ifdef DEBUG_SEEK
579
    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
580
#endif
581
    *ppos = pos;
582
    return dts;
583
}
584

    
585
AVInputFormat mpegps_demuxer = {
586
    "mpeg",
587
    "MPEG PS format",
588
    sizeof(MpegDemuxContext),
589
    mpegps_probe,
590
    mpegps_read_header,
591
    mpegps_read_packet,
592
    mpegps_read_close,
593
    NULL, //mpegps_read_seek,
594
    mpegps_read_dts,
595
    .flags = AVFMT_SHOW_IDS,
596
};