libavformat/mpeg.c

   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_MPEG2VIDEO;
 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,
 590 };