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ffmpeg / libavformat / mpeg.c @ 0c904db1

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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
} MpegDemuxContext;
111

    
112
static int mpegps_read_header(AVFormatContext *s,
113
                              AVFormatParameters *ap)
114
{
115
    MpegDemuxContext *m = s->priv_data;
116
    m->header_state = 0xff;
117
    s->ctx_flags |= AVFMTCTX_NOHEADER;
118

    
119
    /* no need to do more */
120
    return 0;
121
}
122

    
123
static int64_t get_pts(ByteIOContext *pb, int c)
124
{
125
    int64_t pts;
126
    int val;
127

    
128
    if (c < 0)
129
        c = get_byte(pb);
130
    pts = (int64_t)((c >> 1) & 0x07) << 30;
131
    val = get_be16(pb);
132
    pts |= (int64_t)(val >> 1) << 15;
133
    val = get_be16(pb);
134
    pts |= (int64_t)(val >> 1);
135
    return pts;
136
}
137

    
138
static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
139
                                int32_t *header_state)
140
{
141
    unsigned int state, v;
142
    int val, n;
143

    
144
    state = *header_state;
145
    n = *size_ptr;
146
    while (n > 0) {
147
        if (url_feof(pb))
148
            break;
149
        v = get_byte(pb);
150
        n--;
151
        if (state == 0x000001) {
152
            state = ((state << 8) | v) & 0xffffff;
153
            val = state;
154
            goto found;
155
        }
156
        state = ((state << 8) | v) & 0xffffff;
157
    }
158
    val = -1;
159
 found:
160
    *header_state = state;
161
    *size_ptr = n;
162
    return val;
163
}
164

    
165
#if 0 /* unused, remove? */
166
/* XXX: optimize */
167
static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
168
{
169
    int64_t pos, pos_start;
170
    int max_size, start_code;
171

172
    max_size = *size_ptr;
173
    pos_start = url_ftell(pb);
174

175
    /* in order to go faster, we fill the buffer */
176
    pos = pos_start - 16386;
177
    if (pos < 0)
178
        pos = 0;
179
    url_fseek(pb, pos, SEEK_SET);
180
    get_byte(pb);
181

182
    pos = pos_start;
183
    for(;;) {
184
        pos--;
185
        if (pos < 0 || (pos_start - pos) >= max_size) {
186
            start_code = -1;
187
            goto the_end;
188
        }
189
        url_fseek(pb, pos, SEEK_SET);
190
        start_code = get_be32(pb);
191
        if ((start_code & 0xffffff00) == 0x100)
192
            break;
193
    }
194
 the_end:
195
    *size_ptr = pos_start - pos;
196
    return start_code;
197
}
198
#endif
199

    
200
/**
201
 * Extracts stream types from a program stream map
202
 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
203
 *
204
 * @return number of bytes occupied by PSM in the bitstream
205
 */
206
static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
207
{
208
    int psm_length, ps_info_length, es_map_length;
209

    
210
    psm_length = get_be16(pb);
211
    get_byte(pb);
212
    get_byte(pb);
213
    ps_info_length = get_be16(pb);
214

    
215
    /* skip program_stream_info */
216
    url_fskip(pb, ps_info_length);
217
    es_map_length = get_be16(pb);
218

    
219
    /* at least one es available? */
220
    while (es_map_length >= 4){
221
        unsigned char type = get_byte(pb);
222
        unsigned char es_id = get_byte(pb);
223
        uint16_t es_info_length = get_be16(pb);
224
        /* remember mapping from stream id to stream type */
225
        m->psm_es_type[es_id] = type;
226
        /* skip program_stream_info */
227
        url_fskip(pb, es_info_length);
228
        es_map_length -= 4 + es_info_length;
229
    }
230
    get_be32(pb); /* crc32 */
231
    return 2 + psm_length;
232
}
233

    
234
/* read the next PES header. Return its position in ppos
235
   (if not NULL), and its start code, pts and dts.
236
 */
237
static int mpegps_read_pes_header(AVFormatContext *s,
238
                                  int64_t *ppos, int *pstart_code,
239
                                  int64_t *ppts, int64_t *pdts)
240
{
241
    MpegDemuxContext *m = s->priv_data;
242
    int len, size, startcode, c, flags, header_len;
243
    int pes_ext, ext2_len, id_ext, skip;
244
    int64_t pts, dts;
245
    int64_t last_sync= url_ftell(&s->pb);
246

    
247
 error_redo:
248
        url_fseek(&s->pb, last_sync, SEEK_SET);
249
 redo:
250
        /* next start code (should be immediately after) */
251
        m->header_state = 0xff;
252
        size = MAX_SYNC_SIZE;
253
        startcode = find_next_start_code(&s->pb, &size, &m->header_state);
254
        last_sync = url_ftell(&s->pb);
255
    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(&s->pb));
256
    if (startcode < 0)
257
        return AVERROR(EIO);
258
    if (startcode == PACK_START_CODE)
259
        goto redo;
260
    if (startcode == SYSTEM_HEADER_START_CODE)
261
        goto redo;
262
    if (startcode == PADDING_STREAM ||
263
        startcode == PRIVATE_STREAM_2) {
264
        /* skip them */
265
        len = get_be16(&s->pb);
266
        url_fskip(&s->pb, len);
267
        goto redo;
268
    }
269
    if (startcode == PROGRAM_STREAM_MAP) {
270
        mpegps_psm_parse(m, &s->pb);
271
        goto redo;
272
    }
273

    
274
    /* find matching stream */
275
    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
276
          (startcode >= 0x1e0 && startcode <= 0x1ef) ||
277
          (startcode == 0x1bd) || (startcode == 0x1fd)))
278
        goto redo;
279
    if (ppos) {
280
        *ppos = url_ftell(&s->pb) - 4;
281
    }
282
    len = get_be16(&s->pb);
283
    pts =
284
    dts = AV_NOPTS_VALUE;
285
    /* stuffing */
286
    for(;;) {
287
        if (len < 1)
288
            goto error_redo;
289
        c = get_byte(&s->pb);
290
        len--;
291
        /* XXX: for mpeg1, should test only bit 7 */
292
        if (c != 0xff)
293
            break;
294
    }
295
    if ((c & 0xc0) == 0x40) {
296
        /* buffer scale & size */
297
        get_byte(&s->pb);
298
        c = get_byte(&s->pb);
299
        len -= 2;
300
    }
301
    if ((c & 0xe0) == 0x20) {
302
        dts = pts = get_pts(&s->pb, c);
303
        len -= 4;
304
        if (c & 0x10){
305
            dts = get_pts(&s->pb, -1);
306
            len -= 5;
307
        }
308
    } else if ((c & 0xc0) == 0x80) {
309
        /* mpeg 2 PES */
310
#if 0 /* some streams have this field set for no apparent reason */
311
        if ((c & 0x30) != 0) {
312
            /* Encrypted multiplex not handled */
313
            goto redo;
314
        }
315
#endif
316
        flags = get_byte(&s->pb);
317
        header_len = get_byte(&s->pb);
318
        len -= 2;
319
        if (header_len > len)
320
            goto error_redo;
321
        len -= header_len;
322
        if (flags & 0x80) {
323
            dts = pts = get_pts(&s->pb, -1);
324
            header_len -= 5;
325
            if (flags & 0x40) {
326
                dts = get_pts(&s->pb, -1);
327
                header_len -= 5;
328
            }
329
        }
330
        if (flags & 0x01) { /* PES extension */
331
            pes_ext = get_byte(&s->pb);
332
            header_len--;
333
            if (pes_ext & 0x40) { /* pack header - should be zero in PS */
334
                goto error_redo;
335
            }
336
            /* Skip PES private data, program packet sequence counter and P-STD buffer */
337
            skip = (pes_ext >> 4) & 0xb;
338
            skip += skip & 0x9;
339
            url_fskip(&s->pb, skip);
340
            header_len -= skip;
341

    
342
            if (pes_ext & 0x01) { /* PES extension 2 */
343
                ext2_len = get_byte(&s->pb);
344
                header_len--;
345
                if ((ext2_len & 0x7f) > 0) {
346
                    id_ext = get_byte(&s->pb);
347
                    if ((id_ext & 0x80) == 0)
348
                        startcode = ((startcode & 0xff) << 8) | id_ext;
349
                    header_len--;
350
                }
351
            }
352
        }
353
        if(header_len < 0)
354
            goto error_redo;
355
        url_fskip(&s->pb, header_len);
356
    }
357
    else if( c!= 0xf )
358
        goto redo;
359

    
360
    if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
361
        startcode = get_byte(&s->pb);
362
        len--;
363
        if (startcode >= 0x80 && startcode <= 0xcf) {
364
            /* audio: skip header */
365
            get_byte(&s->pb);
366
            get_byte(&s->pb);
367
            get_byte(&s->pb);
368
            len -= 3;
369
            if (startcode >= 0xb0 && startcode <= 0xbf) {
370
                /* MLP/TrueHD audio has a 4-byte header */
371
                get_byte(&s->pb);
372
                len--;
373
            }
374
        }
375
    }
376
    if(len<0)
377
        goto error_redo;
378
    if(dts != AV_NOPTS_VALUE && ppos){
379
        int i;
380
        for(i=0; i<s->nb_streams; i++){
381
            if(startcode == s->streams[i]->id) {
382
                av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
383
            }
384
        }
385
    }
386

    
387
    *pstart_code = startcode;
388
    *ppts = pts;
389
    *pdts = dts;
390
    return len;
391
}
392

    
393
static int mpegps_read_packet(AVFormatContext *s,
394
                              AVPacket *pkt)
395
{
396
    MpegDemuxContext *m = s->priv_data;
397
    AVStream *st;
398
    int len, startcode, i, type, codec_id = 0, es_type;
399
    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
400

    
401
 redo:
402
    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
403
    if (len < 0)
404
        return len;
405

    
406
    /* now find stream */
407
    for(i=0;i<s->nb_streams;i++) {
408
        st = s->streams[i];
409
        if (st->id == startcode)
410
            goto found;
411
    }
412

    
413
    es_type = m->psm_es_type[startcode & 0xff];
414
    if(es_type > 0){
415
        if(es_type == STREAM_TYPE_VIDEO_MPEG1){
416
            codec_id = CODEC_ID_MPEG2VIDEO;
417
            type = CODEC_TYPE_VIDEO;
418
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
419
            codec_id = CODEC_ID_MPEG2VIDEO;
420
            type = CODEC_TYPE_VIDEO;
421
        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
422
                  es_type == STREAM_TYPE_AUDIO_MPEG2){
423
            codec_id = CODEC_ID_MP3;
424
            type = CODEC_TYPE_AUDIO;
425
        } else if(es_type == STREAM_TYPE_AUDIO_AAC){
426
            codec_id = CODEC_ID_AAC;
427
            type = CODEC_TYPE_AUDIO;
428
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
429
            codec_id = CODEC_ID_MPEG4;
430
            type = CODEC_TYPE_VIDEO;
431
        } else if(es_type == STREAM_TYPE_VIDEO_H264){
432
            codec_id = CODEC_ID_H264;
433
            type = CODEC_TYPE_VIDEO;
434
        } else if(es_type == STREAM_TYPE_AUDIO_AC3){
435
            codec_id = CODEC_ID_AC3;
436
            type = CODEC_TYPE_AUDIO;
437
        } else {
438
            goto skip;
439
        }
440
    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
441
        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
442
        unsigned char buf[8];
443
        get_buffer(&s->pb, buf, 8);
444
        url_fseek(&s->pb, -8, SEEK_CUR);
445
        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
446
            codec_id = CODEC_ID_CAVS;
447
        else
448
            codec_id = CODEC_ID_MPEG2VIDEO;
449
        type = CODEC_TYPE_VIDEO;
450
    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
451
        type = CODEC_TYPE_AUDIO;
452
        codec_id = CODEC_ID_MP2;
453
    } else if (startcode >= 0x80 && startcode <= 0x87) {
454
        type = CODEC_TYPE_AUDIO;
455
        codec_id = CODEC_ID_AC3;
456
    } else if ((startcode >= 0x88 && startcode <= 0x8f)
457
               ||( startcode >= 0x98 && startcode <= 0x9f)) {
458
        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
459
        type = CODEC_TYPE_AUDIO;
460
        codec_id = CODEC_ID_DTS;
461
    } else if (startcode >= 0xa0 && startcode <= 0xaf) {
462
        type = CODEC_TYPE_AUDIO;
463
        codec_id = CODEC_ID_PCM_S16BE;
464
    } else if (startcode >= 0xb0 && startcode <= 0xbf) {
465
        type = CODEC_TYPE_AUDIO;
466
        codec_id = CODEC_ID_MLP;
467
    } else if (startcode >= 0xc0 && startcode <= 0xcf) {
468
        /* Used for both AC-3 and E-AC-3 in EVOB files */
469
        type = CODEC_TYPE_AUDIO;
470
        codec_id = CODEC_ID_AC3;
471
    } else if (startcode >= 0x20 && startcode <= 0x3f) {
472
        type = CODEC_TYPE_SUBTITLE;
473
        codec_id = CODEC_ID_DVD_SUBTITLE;
474
    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
475
        type = CODEC_TYPE_VIDEO;
476
        codec_id = CODEC_ID_VC1;
477
    } else {
478
    skip:
479
        /* skip packet */
480
        url_fskip(&s->pb, len);
481
        goto redo;
482
    }
483
    /* no stream found: add a new stream */
484
    st = av_new_stream(s, startcode);
485
    if (!st)
486
        goto skip;
487
    st->codec->codec_type = type;
488
    st->codec->codec_id = codec_id;
489
    if (codec_id != CODEC_ID_PCM_S16BE)
490
        st->need_parsing = AVSTREAM_PARSE_FULL;
491
 found:
492
    if(st->discard >= AVDISCARD_ALL)
493
        goto skip;
494
    if (startcode >= 0xa0 && startcode <= 0xaf) {
495
        int b1, freq;
496

    
497
        /* for LPCM, we just skip the header and consider it is raw
498
           audio data */
499
        if (len <= 3)
500
            goto skip;
501
        get_byte(&s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
502
        b1 = get_byte(&s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
503
        get_byte(&s->pb); /* dynamic range control (0x80 = off) */
504
        len -= 3;
505
        freq = (b1 >> 4) & 3;
506
        st->codec->sample_rate = lpcm_freq_tab[freq];
507
        st->codec->channels = 1 + (b1 & 7);
508
        st->codec->bit_rate = st->codec->channels * st->codec->sample_rate * 2;
509
    }
510
    av_new_packet(pkt, len);
511
    get_buffer(&s->pb, pkt->data, pkt->size);
512
    pkt->pts = pts;
513
    pkt->dts = dts;
514
    pkt->stream_index = st->index;
515
#if 0
516
    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
517
           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
518
#endif
519

    
520
    return 0;
521
}
522

    
523
static int mpegps_read_close(AVFormatContext *s)
524
{
525
    return 0;
526
}
527

    
528
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
529
                               int64_t *ppos, int64_t pos_limit)
530
{
531
    int len, startcode;
532
    int64_t pos, pts, dts;
533

    
534
    pos = *ppos;
535
#ifdef DEBUG_SEEK
536
    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
537
#endif
538
    url_fseek(&s->pb, pos, SEEK_SET);
539
    for(;;) {
540
        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
541
        if (len < 0) {
542
#ifdef DEBUG_SEEK
543
            printf("none (ret=%d)\n", len);
544
#endif
545
            return AV_NOPTS_VALUE;
546
        }
547
        if (startcode == s->streams[stream_index]->id &&
548
            dts != AV_NOPTS_VALUE) {
549
            break;
550
        }
551
        url_fskip(&s->pb, len);
552
    }
553
#ifdef DEBUG_SEEK
554
    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
555
#endif
556
    *ppos = pos;
557
    return dts;
558
}
559

    
560
AVInputFormat mpegps_demuxer = {
561
    "mpeg",
562
    "MPEG PS format",
563
    sizeof(MpegDemuxContext),
564
    mpegps_probe,
565
    mpegps_read_header,
566
    mpegps_read_packet,
567
    mpegps_read_close,
568
    NULL, //mpegps_read_seek,
569
    mpegps_read_dts,
570
    .flags = AVFMT_SHOW_IDS,
571
};