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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
    uint8_t buf[5];
124

    
125
    buf[0] = c<0 ? get_byte(pb) : c;
126
    get_buffer(pb, buf+1, 4);
127

    
128
    return ff_parse_pes_pts(buf);
129
}
130

    
131
static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
132
                                int32_t *header_state)
133
{
134
    unsigned int state, v;
135
    int val, n;
136

    
137
    state = *header_state;
138
    n = *size_ptr;
139
    while (n > 0) {
140
        if (url_feof(pb))
141
            break;
142
        v = get_byte(pb);
143
        n--;
144
        if (state == 0x000001) {
145
            state = ((state << 8) | v) & 0xffffff;
146
            val = state;
147
            goto found;
148
        }
149
        state = ((state << 8) | v) & 0xffffff;
150
    }
151
    val = -1;
152
 found:
153
    *header_state = state;
154
    *size_ptr = n;
155
    return val;
156
}
157

    
158
#if 0 /* unused, remove? */
159
/* XXX: optimize */
160
static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
161
{
162
    int64_t pos, pos_start;
163
    int max_size, start_code;
164

165
    max_size = *size_ptr;
166
    pos_start = url_ftell(pb);
167

168
    /* in order to go faster, we fill the buffer */
169
    pos = pos_start - 16386;
170
    if (pos < 0)
171
        pos = 0;
172
    url_fseek(pb, pos, SEEK_SET);
173
    get_byte(pb);
174

175
    pos = pos_start;
176
    for(;;) {
177
        pos--;
178
        if (pos < 0 || (pos_start - pos) >= max_size) {
179
            start_code = -1;
180
            goto the_end;
181
        }
182
        url_fseek(pb, pos, SEEK_SET);
183
        start_code = get_be32(pb);
184
        if ((start_code & 0xffffff00) == 0x100)
185
            break;
186
    }
187
 the_end:
188
    *size_ptr = pos_start - pos;
189
    return start_code;
190
}
191
#endif
192

    
193
/**
194
 * Extracts stream types from a program stream map
195
 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
196
 *
197
 * @return number of bytes occupied by PSM in the bitstream
198
 */
199
static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
200
{
201
    int psm_length, ps_info_length, es_map_length;
202

    
203
    psm_length = get_be16(pb);
204
    get_byte(pb);
205
    get_byte(pb);
206
    ps_info_length = get_be16(pb);
207

    
208
    /* skip program_stream_info */
209
    url_fskip(pb, ps_info_length);
210
    es_map_length = get_be16(pb);
211

    
212
    /* at least one es available? */
213
    while (es_map_length >= 4){
214
        unsigned char type = get_byte(pb);
215
        unsigned char es_id = get_byte(pb);
216
        uint16_t es_info_length = get_be16(pb);
217
        /* remember mapping from stream id to stream type */
218
        m->psm_es_type[es_id] = type;
219
        /* skip program_stream_info */
220
        url_fskip(pb, es_info_length);
221
        es_map_length -= 4 + es_info_length;
222
    }
223
    get_be32(pb); /* crc32 */
224
    return 2 + psm_length;
225
}
226

    
227
/* read the next PES header. Return its position in ppos
228
   (if not NULL), and its start code, pts and dts.
229
 */
230
static int mpegps_read_pes_header(AVFormatContext *s,
231
                                  int64_t *ppos, int *pstart_code,
232
                                  int64_t *ppts, int64_t *pdts)
233
{
234
    MpegDemuxContext *m = s->priv_data;
235
    int len, size, startcode, c, flags, header_len;
236
    int pes_ext, ext2_len, id_ext, skip;
237
    int64_t pts, dts;
238
    int64_t last_sync= url_ftell(s->pb);
239

    
240
 error_redo:
241
        url_fseek(s->pb, last_sync, SEEK_SET);
242
 redo:
243
        /* next start code (should be immediately after) */
244
        m->header_state = 0xff;
245
        size = MAX_SYNC_SIZE;
246
        startcode = find_next_start_code(s->pb, &size, &m->header_state);
247
        last_sync = url_ftell(s->pb);
248
    //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(s->pb));
249
    if (startcode < 0)
250
        return AVERROR(EIO);
251
    if (startcode == PACK_START_CODE)
252
        goto redo;
253
    if (startcode == SYSTEM_HEADER_START_CODE)
254
        goto redo;
255
    if (startcode == PADDING_STREAM) {
256
        url_fskip(s->pb, get_be16(s->pb));
257
        goto redo;
258
    }
259
    if (startcode == PRIVATE_STREAM_2) {
260
        len = get_be16(s->pb);
261
        if (!m->sofdec) {
262
            while (len-- >= 6) {
263
                if (get_byte(s->pb) == 'S') {
264
                    uint8_t buf[5];
265
                    get_buffer(s->pb, buf, sizeof(buf));
266
                    m->sofdec = !memcmp(buf, "ofdec", 5);
267
                    len -= sizeof(buf);
268
                    break;
269
                }
270
            }
271
            m->sofdec -= !m->sofdec;
272
        }
273
        url_fskip(s->pb, len);
274
        goto redo;
275
    }
276
    if (startcode == PROGRAM_STREAM_MAP) {
277
        mpegps_psm_parse(m, s->pb);
278
        goto redo;
279
    }
280

    
281
    /* find matching stream */
282
    if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
283
          (startcode >= 0x1e0 && startcode <= 0x1ef) ||
284
          (startcode == 0x1bd) || (startcode == 0x1fd)))
285
        goto redo;
286
    if (ppos) {
287
        *ppos = url_ftell(s->pb) - 4;
288
    }
289
    len = get_be16(s->pb);
290
    pts =
291
    dts = AV_NOPTS_VALUE;
292
    /* stuffing */
293
    for(;;) {
294
        if (len < 1)
295
            goto error_redo;
296
        c = get_byte(s->pb);
297
        len--;
298
        /* XXX: for mpeg1, should test only bit 7 */
299
        if (c != 0xff)
300
            break;
301
    }
302
    if ((c & 0xc0) == 0x40) {
303
        /* buffer scale & size */
304
        get_byte(s->pb);
305
        c = get_byte(s->pb);
306
        len -= 2;
307
    }
308
    if ((c & 0xe0) == 0x20) {
309
        dts = pts = get_pts(s->pb, c);
310
        len -= 4;
311
        if (c & 0x10){
312
            dts = get_pts(s->pb, -1);
313
            len -= 5;
314
        }
315
    } else if ((c & 0xc0) == 0x80) {
316
        /* mpeg 2 PES */
317
#if 0 /* some streams have this field set for no apparent reason */
318
        if ((c & 0x30) != 0) {
319
            /* Encrypted multiplex not handled */
320
            goto redo;
321
        }
322
#endif
323
        flags = get_byte(s->pb);
324
        header_len = get_byte(s->pb);
325
        len -= 2;
326
        if (header_len > len)
327
            goto error_redo;
328
        len -= header_len;
329
        if (flags & 0x80) {
330
            dts = pts = get_pts(s->pb, -1);
331
            header_len -= 5;
332
            if (flags & 0x40) {
333
                dts = get_pts(s->pb, -1);
334
                header_len -= 5;
335
            }
336
        }
337
        if (flags & 0x3f && header_len == 0){
338
            flags &= 0xC0;
339
            av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");
340
        }
341
        if (flags & 0x01) { /* PES extension */
342
            pes_ext = get_byte(s->pb);
343
            header_len--;
344
            /* Skip PES private data, program packet sequence counter and P-STD buffer */
345
            skip = (pes_ext >> 4) & 0xb;
346
            skip += skip & 0x9;
347
            if (pes_ext & 0x40 || skip > header_len){
348
                av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);
349
                pes_ext=skip=0;
350
            }
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
               !url_is_streamed(s->pb) /* index useless on streams anyway */) {
395
                ff_reduce_index(s, i);
396
                av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
397
            }
398
        }
399
    }
400

    
401
    *pstart_code = startcode;
402
    *ppts = pts;
403
    *pdts = dts;
404
    return len;
405
}
406

    
407
static int mpegps_read_packet(AVFormatContext *s,
408
                              AVPacket *pkt)
409
{
410
    MpegDemuxContext *m = s->priv_data;
411
    AVStream *st;
412
    int len, startcode, i, type, codec_id = 0, es_type;
413
    int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
414

    
415
 redo:
416
    len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
417
    if (len < 0)
418
        return len;
419

    
420
    /* now find stream */
421
    for(i=0;i<s->nb_streams;i++) {
422
        st = s->streams[i];
423
        if (st->id == startcode)
424
            goto found;
425
    }
426

    
427
    es_type = m->psm_es_type[startcode & 0xff];
428
    if(es_type > 0){
429
        if(es_type == STREAM_TYPE_VIDEO_MPEG1){
430
            codec_id = CODEC_ID_MPEG2VIDEO;
431
            type = CODEC_TYPE_VIDEO;
432
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
433
            codec_id = CODEC_ID_MPEG2VIDEO;
434
            type = CODEC_TYPE_VIDEO;
435
        } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
436
                  es_type == STREAM_TYPE_AUDIO_MPEG2){
437
            codec_id = CODEC_ID_MP3;
438
            type = CODEC_TYPE_AUDIO;
439
        } else if(es_type == STREAM_TYPE_AUDIO_AAC){
440
            codec_id = CODEC_ID_AAC;
441
            type = CODEC_TYPE_AUDIO;
442
        } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
443
            codec_id = CODEC_ID_MPEG4;
444
            type = CODEC_TYPE_VIDEO;
445
        } else if(es_type == STREAM_TYPE_VIDEO_H264){
446
            codec_id = CODEC_ID_H264;
447
            type = CODEC_TYPE_VIDEO;
448
        } else if(es_type == STREAM_TYPE_AUDIO_AC3){
449
            codec_id = CODEC_ID_AC3;
450
            type = CODEC_TYPE_AUDIO;
451
        } else {
452
            goto skip;
453
        }
454
    } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
455
        static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
456
        unsigned char buf[8];
457
        get_buffer(s->pb, buf, 8);
458
        url_fseek(s->pb, -8, SEEK_CUR);
459
        if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
460
            codec_id = CODEC_ID_CAVS;
461
        else
462
            codec_id = CODEC_ID_PROBE;
463
        type = CODEC_TYPE_VIDEO;
464
    } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
465
        type = CODEC_TYPE_AUDIO;
466
        codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
467
    } else if (startcode >= 0x80 && startcode <= 0x87) {
468
        type = CODEC_TYPE_AUDIO;
469
        codec_id = CODEC_ID_AC3;
470
    } else if ((startcode >= 0x88 && startcode <= 0x8f)
471
               ||( startcode >= 0x98 && startcode <= 0x9f)) {
472
        /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
473
        type = CODEC_TYPE_AUDIO;
474
        codec_id = CODEC_ID_DTS;
475
    } else if (startcode >= 0xa0 && startcode <= 0xaf) {
476
        type = CODEC_TYPE_AUDIO;
477
        /* 16 bit form will be handled as CODEC_ID_PCM_S16BE */
478
        codec_id = CODEC_ID_PCM_DVD;
479
    } else if (startcode >= 0xb0 && startcode <= 0xbf) {
480
        type = CODEC_TYPE_AUDIO;
481
        codec_id = CODEC_ID_MLP;
482
    } else if (startcode >= 0xc0 && startcode <= 0xcf) {
483
        /* Used for both AC-3 and E-AC-3 in EVOB files */
484
        type = CODEC_TYPE_AUDIO;
485
        codec_id = CODEC_ID_AC3;
486
    } else if (startcode >= 0x20 && startcode <= 0x3f) {
487
        type = CODEC_TYPE_SUBTITLE;
488
        codec_id = CODEC_ID_DVD_SUBTITLE;
489
    } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
490
        type = CODEC_TYPE_VIDEO;
491
        codec_id = CODEC_ID_VC1;
492
    } else {
493
    skip:
494
        /* skip packet */
495
        url_fskip(s->pb, len);
496
        goto redo;
497
    }
498
    /* no stream found: add a new stream */
499
    st = av_new_stream(s, startcode);
500
    if (!st)
501
        goto skip;
502
    st->codec->codec_type = type;
503
    st->codec->codec_id = codec_id;
504
    if (codec_id != CODEC_ID_PCM_S16BE)
505
        st->need_parsing = AVSTREAM_PARSE_FULL;
506
 found:
507
    if(st->discard >= AVDISCARD_ALL)
508
        goto skip;
509
    if (startcode >= 0xa0 && startcode <= 0xaf) {
510
        int b1, freq;
511

    
512
        /* for LPCM, we just skip the header and consider it is raw
513
           audio data */
514
        if (len <= 3)
515
            goto skip;
516
        get_byte(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
517
        b1 = get_byte(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
518
        get_byte(s->pb); /* dynamic range control (0x80 = off) */
519
        len -= 3;
520
        freq = (b1 >> 4) & 3;
521
        st->codec->sample_rate = lpcm_freq_tab[freq];
522
        st->codec->channels = 1 + (b1 & 7);
523
        st->codec->bits_per_sample = 16 + ((b1 >> 6) & 3) * 4;
524
        st->codec->bit_rate = st->codec->channels *
525
                              st->codec->sample_rate *
526
                              st->codec->bits_per_sample;
527
        if (st->codec->bits_per_sample == 16)
528
            st->codec->codec_id = CODEC_ID_PCM_S16BE;
529
        else if (st->codec->bits_per_sample == 28)
530
            return AVERROR(EINVAL);
531
    }
532
    av_new_packet(pkt, len);
533
    get_buffer(s->pb, pkt->data, pkt->size);
534
    pkt->pts = pts;
535
    pkt->dts = dts;
536
    pkt->stream_index = st->index;
537
#if 0
538
    av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
539
           pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
540
#endif
541

    
542
    return 0;
543
}
544

    
545
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
546
                               int64_t *ppos, int64_t pos_limit)
547
{
548
    int len, startcode;
549
    int64_t pos, pts, dts;
550

    
551
    pos = *ppos;
552
#ifdef DEBUG_SEEK
553
    printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
554
#endif
555
    if (url_fseek(s->pb, pos, SEEK_SET) < 0)
556
        return AV_NOPTS_VALUE;
557

    
558
    for(;;) {
559
        len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
560
        if (len < 0) {
561
#ifdef DEBUG_SEEK
562
            printf("none (ret=%d)\n", len);
563
#endif
564
            return AV_NOPTS_VALUE;
565
        }
566
        if (startcode == s->streams[stream_index]->id &&
567
            dts != AV_NOPTS_VALUE) {
568
            break;
569
        }
570
        url_fskip(s->pb, len);
571
    }
572
#ifdef DEBUG_SEEK
573
    printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
574
#endif
575
    *ppos = pos;
576
    return dts;
577
}
578

    
579
AVInputFormat mpegps_demuxer = {
580
    "mpeg",
581
    NULL_IF_CONFIG_SMALL("MPEG-PS format"),
582
    sizeof(MpegDemuxContext),
583
    mpegps_probe,
584
    mpegps_read_header,
585
    mpegps_read_packet,
586
    NULL,
587
    NULL, //mpegps_read_seek,
588
    mpegps_read_dts,
589
    .flags = AVFMT_SHOW_IDS|AVFMT_TS_DISCONT,
590
};