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ffmpeg / libavformat / mpeg.c @ 3abe5fbd

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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
        p+=5;
46
    }else if((*p&0xF0) == 0x30){
47
        pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
48
        p+=10;
49
    }else
50
        pes1 = *p == 0x0F;
51

    
52
    return pes1||pes2;
53
}
54

    
55
static int mpegps_probe(AVProbeData *p)
56
{
57
    uint32_t code= -1;
58
    int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
59
    int i;
60
    int score=0;
61

    
62
    for(i=0; i<p->buf_size; i++){
63
        code = (code<<8) + p->buf[i];
64
        if ((code & 0xffffff00) == 0x100) {
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 == PRIVATE_STREAM_1)    priv1++;
69
            else if(code == PACK_START_CODE)     pspack++;
70
            else if((code & 0xf0) == VIDEO_ID && pes) vid++;
71
            else if((code & 0xe0) == AUDIO_ID && pes) audio++;
72

    
73
            else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
74
            else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
75
        }
76
    }
77

    
78
    if(vid+audio > invalid)     /* invalid VDR files nd short PES streams */
79
        score= AVPROBE_SCORE_MAX/4;
80

    
81
//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, p->buf_size);
82
    if(sys>invalid && sys*9 <= pspack*10)
83
        return AVPROBE_SCORE_MAX/2+2; // +1 for .mpg
84
    if(priv1 + vid + audio > invalid && (priv1+vid+audio)*9 <= pspack*10)
85
        return AVPROBE_SCORE_MAX/2+2; // +1 for .mpg
86
    if((!!vid ^ !!audio) && (audio+vid > 1) && !sys && !pspack && p->buf_size>2048) /* PES stream */
87
        return AVPROBE_SCORE_MAX/2+2;
88

    
89
    //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
90
    return score;
91
}
92

    
93

    
94
typedef struct MpegDemuxContext {
95
    int32_t header_state;
96
    unsigned char psm_es_type[256];
97
    int sofdec;
98
} MpegDemuxContext;
99

    
100
static int mpegps_read_header(AVFormatContext *s,
101
                              AVFormatParameters *ap)
102
{
103
    MpegDemuxContext *m = s->priv_data;
104
    const char *sofdec = "Sofdec";
105
    int v, i = 0;
106

    
107
    m->header_state = 0xff;
108
    s->ctx_flags |= AVFMTCTX_NOHEADER;
109

    
110
    m->sofdec = -1;
111
    do {
112
        v = get_byte(s->pb);
113
        m->header_state = m->header_state << 8 | v;
114
        m->sofdec++;
115
    } while (v == sofdec[i] && i++ < 6);
116

    
117
    /* no need to do more */
118
    return 0;
119
}
120

    
121
static int64_t get_pts(ByteIOContext *pb, int c)
122
{
123
    int64_t pts;
124
    int val;
125

    
126
    if (c < 0)
127
        c = get_byte(pb);
128
    pts = (int64_t)(c & 0x0e) << 29;
129
    val = get_be16(pb);
130
    pts |= (int64_t)(val >> 1) << 15;
131
    val = get_be16(pb);
132
    pts |= (int64_t)(val >> 1);
133
    return pts;
134
}
135

    
136
static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
137
                                int32_t *header_state)
138
{
139
    unsigned int state, v;
140
    int val, n;
141

    
142
    state = *header_state;
143
    n = *size_ptr;
144
    while (n > 0) {
145
        if (url_feof(pb))
146
            break;
147
        v = get_byte(pb);
148
        n--;
149
        if (state == 0x000001) {
150
            state = ((state << 8) | v) & 0xffffff;
151
            val = state;
152
            goto found;
153
        }
154
        state = ((state << 8) | v) & 0xffffff;
155
    }
156
    val = -1;
157
 found:
158
    *header_state = state;
159
    *size_ptr = n;
160
    return val;
161
}
162

    
163
#if 0 /* unused, remove? */
164
/* XXX: optimize */
165
static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
166
{
167
    int64_t pos, pos_start;
168
    int max_size, start_code;
169

170
    max_size = *size_ptr;
171
    pos_start = url_ftell(pb);
172

173
    /* in order to go faster, we fill the buffer */
174
    pos = pos_start - 16386;
175
    if (pos < 0)
176
        pos = 0;
177
    url_fseek(pb, pos, SEEK_SET);
178
    get_byte(pb);
179

180
    pos = pos_start;
181
    for(;;) {
182
        pos--;
183
        if (pos < 0 || (pos_start - pos) >= max_size) {
184
            start_code = -1;
185
            goto the_end;
186
        }
187
        url_fseek(pb, pos, SEEK_SET);
188
        start_code = get_be32(pb);
189
        if ((start_code & 0xffffff00) == 0x100)
190
            break;
191
    }
192
 the_end:
193
    *size_ptr = pos_start - pos;
194
    return start_code;
195
}
196
#endif
197

    
198
/**
199
 * Extracts stream types from a program stream map
200
 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
201
 *
202
 * @return number of bytes occupied by PSM in the bitstream
203
 */
204
static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
205
{
206
    int psm_length, ps_info_length, es_map_length;
207

    
208
    psm_length = get_be16(pb);
209
    get_byte(pb);
210
    get_byte(pb);
211
    ps_info_length = get_be16(pb);
212

    
213
    /* skip program_stream_info */
214
    url_fskip(pb, ps_info_length);
215
    es_map_length = get_be16(pb);
216

    
217
    /* at least one es available? */
218
    while (es_map_length >= 4){
219
        unsigned char type = get_byte(pb);
220
        unsigned char es_id = get_byte(pb);
221
        uint16_t es_info_length = get_be16(pb);
222
        /* remember mapping from stream id to stream type */
223
        m->psm_es_type[es_id] = type;
224
        /* skip program_stream_info */
225
        url_fskip(pb, es_info_length);
226
        es_map_length -= 4 + es_info_length;
227
    }
228
    get_be32(pb); /* crc32 */
229
    return 2 + psm_length;
230
}
231

    
232
/* read the next PES header. Return its position in ppos
233
   (if not NULL), and its start code, pts and dts.
234
 */
235
static int mpegps_read_pes_header(AVFormatContext *s,
236
                                  int64_t *ppos, int *pstart_code,
237
                                  int64_t *ppts, int64_t *pdts)
238
{
239
    MpegDemuxContext *m = s->priv_data;
240
    int len, size, startcode, c, flags, header_len;
241
    int pes_ext, ext2_len, id_ext, skip;
242
    int64_t pts, dts;
243
    int64_t last_sync= url_ftell(s->pb);
244

    
245
 error_redo:
246
        url_fseek(s->pb, last_sync, SEEK_SET);
247
 redo:
248
        /* next start code (should be immediately after) */
249
        m->header_state = 0xff;
250
        size = MAX_SYNC_SIZE;
251
        startcode = find_next_start_code(s->pb, &size, &m->header_state);
252
        last_sync = url_ftell(s->pb);
253
    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(s->pb));
254
    if (startcode < 0)
255
        return AVERROR(EIO);
256
    if (startcode == PACK_START_CODE)
257
        goto redo;
258
    if (startcode == SYSTEM_HEADER_START_CODE)
259
        goto redo;
260
    if (startcode == PADDING_STREAM) {
261
        url_fskip(s->pb, get_be16(s->pb));
262
        goto redo;
263
    }
264
    if (startcode == PRIVATE_STREAM_2) {
265
        len = get_be16(s->pb);
266
        if (!m->sofdec) {
267
            while (len-- >= 6) {
268
                if (get_byte(s->pb) == 'S') {
269
                    uint8_t buf[5];
270
                    get_buffer(s->pb, buf, sizeof(buf));
271
                    m->sofdec = !memcmp(buf, "ofdec", 5);
272
                    len -= sizeof(buf);
273
                    break;
274
                }
275
            }
276
            m->sofdec -= !m->sofdec;
277
        }
278
        url_fskip(s->pb, len);
279
        goto redo;
280
    }
281
    if (startcode == PROGRAM_STREAM_MAP) {
282
        mpegps_psm_parse(m, s->pb);
283
        goto redo;
284
    }
285

    
286
    /* find matching stream */
287
    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
288
          (startcode >= 0x1e0 && startcode <= 0x1ef) ||
289
          (startcode == 0x1bd) || (startcode == 0x1fd)))
290
        goto redo;
291
    if (ppos) {
292
        *ppos = url_ftell(s->pb) - 4;
293
    }
294
    len = get_be16(s->pb);
295
    pts =
296
    dts = AV_NOPTS_VALUE;
297
    /* stuffing */
298
    for(;;) {
299
        if (len < 1)
300
            goto error_redo;
301
        c = get_byte(s->pb);
302
        len--;
303
        /* XXX: for mpeg1, should test only bit 7 */
304
        if (c != 0xff)
305
            break;
306
    }
307
    if ((c & 0xc0) == 0x40) {
308
        /* buffer scale & size */
309
        get_byte(s->pb);
310
        c = get_byte(s->pb);
311
        len -= 2;
312
    }
313
    if ((c & 0xe0) == 0x20) {
314
        dts = pts = get_pts(s->pb, c);
315
        len -= 4;
316
        if (c & 0x10){
317
            dts = get_pts(s->pb, -1);
318
            len -= 5;
319
        }
320
    } else if ((c & 0xc0) == 0x80) {
321
        /* mpeg 2 PES */
322
#if 0 /* some streams have this field set for no apparent reason */
323
        if ((c & 0x30) != 0) {
324
            /* Encrypted multiplex not handled */
325
            goto redo;
326
        }
327
#endif
328
        flags = get_byte(s->pb);
329
        header_len = get_byte(s->pb);
330
        len -= 2;
331
        if (header_len > len)
332
            goto error_redo;
333
        len -= header_len;
334
        if (flags & 0x80) {
335
            dts = pts = get_pts(s->pb, -1);
336
            header_len -= 5;
337
            if (flags & 0x40) {
338
                dts = get_pts(s->pb, -1);
339
                header_len -= 5;
340
            }
341
        }
342
        if (flags & 0x01) { /* PES extension */
343
            pes_ext = get_byte(s->pb);
344
            header_len--;
345
            if (pes_ext & 0x40) { /* pack header - should be zero in PS */
346
                goto error_redo;
347
            }
348
            /* Skip PES private data, program packet sequence counter and P-STD buffer */
349
            skip = (pes_ext >> 4) & 0xb;
350
            skip += skip & 0x9;
351
            url_fskip(s->pb, skip);
352
            header_len -= skip;
353

    
354
            if (pes_ext & 0x01) { /* PES extension 2 */
355
                ext2_len = get_byte(s->pb);
356
                header_len--;
357
                if ((ext2_len & 0x7f) > 0) {
358
                    id_ext = get_byte(s->pb);
359
                    if ((id_ext & 0x80) == 0)
360
                        startcode = ((startcode & 0xff) << 8) | id_ext;
361
                    header_len--;
362
                }
363
            }
364
        }
365
        if(header_len < 0)
366
            goto error_redo;
367
        url_fskip(s->pb, header_len);
368
    }
369
    else if( c!= 0xf )
370
        goto redo;
371

    
372
    if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
373
        startcode = get_byte(s->pb);
374
        len--;
375
        if (startcode >= 0x80 && startcode <= 0xcf) {
376
            /* audio: skip header */
377
            get_byte(s->pb);
378
            get_byte(s->pb);
379
            get_byte(s->pb);
380
            len -= 3;
381
            if (startcode >= 0xb0 && startcode <= 0xbf) {
382
                /* MLP/TrueHD audio has a 4-byte header */
383
                get_byte(s->pb);
384
                len--;
385
            }
386
        }
387
    }
388
    if(len<0)
389
        goto error_redo;
390
    if(dts != AV_NOPTS_VALUE && ppos){
391
        int i;
392
        for(i=0; i<s->nb_streams; i++){
393
            if(startcode == s->streams[i]->id) {
394
                av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
395
            }
396
        }
397
    }
398

    
399
    *pstart_code = startcode;
400
    *ppts = pts;
401
    *pdts = dts;
402
    return len;
403
}
404

    
405
static int mpegps_read_packet(AVFormatContext *s,
406
                              AVPacket *pkt)
407
{
408
    MpegDemuxContext *m = s->priv_data;
409
    AVStream *st;
410
    int len, startcode, i, type, codec_id = 0, es_type;
411
    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
412

    
413
 redo:
414
    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
415
    if (len < 0)
416
        return len;
417

    
418
    /* now find stream */
419
    for(i=0;i<s->nb_streams;i++) {
420
        st = s->streams[i];
421
        if (st->id == startcode)
422
            goto found;
423
    }
424

    
425
    es_type = m->psm_es_type[startcode & 0xff];
426
    if(es_type > 0){
427
        if(es_type == STREAM_TYPE_VIDEO_MPEG1){
428
            codec_id = CODEC_ID_MPEG2VIDEO;
429
            type = CODEC_TYPE_VIDEO;
430
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
431
            codec_id = CODEC_ID_MPEG2VIDEO;
432
            type = CODEC_TYPE_VIDEO;
433
        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
434
                  es_type == STREAM_TYPE_AUDIO_MPEG2){
435
            codec_id = CODEC_ID_MP3;
436
            type = CODEC_TYPE_AUDIO;
437
        } else if(es_type == STREAM_TYPE_AUDIO_AAC){
438
            codec_id = CODEC_ID_AAC;
439
            type = CODEC_TYPE_AUDIO;
440
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
441
            codec_id = CODEC_ID_MPEG4;
442
            type = CODEC_TYPE_VIDEO;
443
        } else if(es_type == STREAM_TYPE_VIDEO_H264){
444
            codec_id = CODEC_ID_H264;
445
            type = CODEC_TYPE_VIDEO;
446
        } else if(es_type == STREAM_TYPE_AUDIO_AC3){
447
            codec_id = CODEC_ID_AC3;
448
            type = CODEC_TYPE_AUDIO;
449
        } else {
450
            goto skip;
451
        }
452
    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
453
        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
454
        unsigned char buf[8];
455
        get_buffer(s->pb, buf, 8);
456
        url_fseek(s->pb, -8, SEEK_CUR);
457
        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
458
            codec_id = CODEC_ID_CAVS;
459
        else
460
            codec_id = CODEC_ID_MPEG2VIDEO;
461
        type = CODEC_TYPE_VIDEO;
462
    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
463
        type = CODEC_TYPE_AUDIO;
464
        codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
465
    } else if (startcode >= 0x80 && startcode <= 0x87) {
466
        type = CODEC_TYPE_AUDIO;
467
        codec_id = CODEC_ID_AC3;
468
    } else if ((startcode >= 0x88 && startcode <= 0x8f)
469
               ||( startcode >= 0x98 && startcode <= 0x9f)) {
470
        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
471
        type = CODEC_TYPE_AUDIO;
472
        codec_id = CODEC_ID_DTS;
473
    } else if (startcode >= 0xa0 && startcode <= 0xaf) {
474
        type = CODEC_TYPE_AUDIO;
475
        codec_id = CODEC_ID_PCM_S16BE;
476
    } else if (startcode >= 0xb0 && startcode <= 0xbf) {
477
        type = CODEC_TYPE_AUDIO;
478
        codec_id = CODEC_ID_MLP;
479
    } else if (startcode >= 0xc0 && startcode <= 0xcf) {
480
        /* Used for both AC-3 and E-AC-3 in EVOB files */
481
        type = CODEC_TYPE_AUDIO;
482
        codec_id = CODEC_ID_AC3;
483
    } else if (startcode >= 0x20 && startcode <= 0x3f) {
484
        type = CODEC_TYPE_SUBTITLE;
485
        codec_id = CODEC_ID_DVD_SUBTITLE;
486
    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
487
        type = CODEC_TYPE_VIDEO;
488
        codec_id = CODEC_ID_VC1;
489
    } else {
490
    skip:
491
        /* skip packet */
492
        url_fskip(s->pb, len);
493
        goto redo;
494
    }
495
    /* no stream found: add a new stream */
496
    st = av_new_stream(s, startcode);
497
    if (!st)
498
        goto skip;
499
    st->codec->codec_type = type;
500
    st->codec->codec_id = codec_id;
501
    if (codec_id != CODEC_ID_PCM_S16BE)
502
        st->need_parsing = AVSTREAM_PARSE_FULL;
503
 found:
504
    if(st->discard >= AVDISCARD_ALL)
505
        goto skip;
506
    if (startcode >= 0xa0 && startcode <= 0xaf) {
507
        int b1, freq;
508

    
509
        /* for LPCM, we just skip the header and consider it is raw
510
           audio data */
511
        if (len <= 3)
512
            goto skip;
513
        get_byte(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
514
        b1 = get_byte(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
515
        get_byte(s->pb); /* dynamic range control (0x80 = off) */
516
        len -= 3;
517
        freq = (b1 >> 4) & 3;
518
        st->codec->sample_rate = lpcm_freq_tab[freq];
519
        st->codec->channels = 1 + (b1 & 7);
520
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate * 2;
521
    }
522
    av_new_packet(pkt, len);
523
    get_buffer(s->pb, pkt->data, pkt->size);
524
    pkt->pts = pts;
525
    pkt->dts = dts;
526
    pkt->stream_index = st->index;
527
#if 0
528
    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
529
           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
530
#endif
531

    
532
    return 0;
533
}
534

    
535
static int mpegps_read_close(AVFormatContext *s)
536
{
537
    return 0;
538
}
539

    
540
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
541
                               int64_t *ppos, int64_t pos_limit)
542
{
543
    int len, startcode;
544
    int64_t pos, pts, dts;
545

    
546
    pos = *ppos;
547
#ifdef DEBUG_SEEK
548
    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
549
#endif
550
    url_fseek(s->pb, pos, SEEK_SET);
551
    for(;;) {
552
        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
553
        if (len < 0) {
554
#ifdef DEBUG_SEEK
555
            printf("none (ret=%d)\n", len);
556
#endif
557
            return AV_NOPTS_VALUE;
558
        }
559
        if (startcode == s->streams[stream_index]->id &&
560
            dts != AV_NOPTS_VALUE) {
561
            break;
562
        }
563
        url_fskip(s->pb, len);
564
    }
565
#ifdef DEBUG_SEEK
566
    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
567
#endif
568
    *ppos = pos;
569
    return dts;
570
}
571

    
572
AVInputFormat mpegps_demuxer = {
573
    "mpeg",
574
    "MPEG PS format",
575
    sizeof(MpegDemuxContext),
576
    mpegps_probe,
577
    mpegps_read_header,
578
    mpegps_read_packet,
579
    mpegps_read_close,
580
    NULL, //mpegps_read_seek,
581
    mpegps_read_dts,
582
    .flags = AVFMT_SHOW_IDS,
583
};