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     }else if((*p&0xF0) == 0x30){
  46         pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
  47     }else
  48         pes1 = *p == 0x0F;
  49
  50     return pes1||pes2;
  51 }
  52
  53 static int mpegps_probe(AVProbeData *p)
  54 {
  55     uint32_t code= -1;
  56     int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
  57     int i;
  58     int score=0;
  59
  60     for(i=0; i<p->buf_size; i++){
  61         code = (code<<8) + p->buf[i];
  62         if ((code & 0xffffff00) == 0x100) {
  63             int pes= check_pes(p->buf+i, p->buf+p->buf_size);
  64
  65             if(code == SYSTEM_HEADER_START_CODE) sys++;
  66             else if(code == PRIVATE_STREAM_1)    priv1++;
  67             else if(code == PACK_START_CODE)     pspack++;
  68             else if((code & 0xf0) == VIDEO_ID &&  pes) vid++;
  69             else if((code & 0xe0) == AUDIO_ID &&  pes) audio++;
  70
  71             else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
  72             else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
  73         }
  74     }
  75
  76     if(vid+audio > invalid)     /* invalid VDR files nd short PES streams */
  77         score= AVPROBE_SCORE_MAX/4;
  78
  79 //av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, p->buf_size);
  80     if(sys>invalid && sys*9 <= pspack*10)
  81         return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
  82     if(priv1 + vid + audio > invalid && (priv1+vid+audio)*9 <= pspack*10)
  83         return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
  84     if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */
  85         return (audio > 12 || vid > 3) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4;
  86
  87     //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
  88     //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6
  89     return score;
  90 }
  91
  92
  93 typedef struct MpegDemuxContext {
  94     int32_t header_state;
  95     unsigned char psm_es_type[256];
  96     int sofdec;
  97 } MpegDemuxContext;
  98
  99 static int mpegps_read_header(AVFormatContext *s,
 100                               AVFormatParameters *ap)
 101 {
 102     MpegDemuxContext *m = s->priv_data;
 103     const char *sofdec = "Sofdec";
 104     int v, i = 0;
 105
 106     m->header_state = 0xff;
 107     s->ctx_flags |= AVFMTCTX_NOHEADER;
 108
 109     m->sofdec = -1;
 110     do {
 111         v = get_byte(s->pb);
 112         m->header_state = m->header_state << 8 | v;
 113         m->sofdec++;
 114     } while (v == sofdec[i] && i++ < 6);
 115
 116     m->sofdec = (m->sofdec == 6) ? 1 : 0;
 117
 118     /* no need to do more */
 119     return 0;
 120 }
 121
 122 static int64_t get_pts(ByteIOContext *pb, int c)
 123 {
 124     uint8_t buf[5];
 125
 126     buf[0] = c<0 ? get_byte(pb) : c;
 127     get_buffer(pb, buf+1, 4);
 128
 129     return ff_parse_pes_pts(buf);
 130 }
 131
 132 static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
 133                                 int32_t *header_state)
 134 {
 135     unsigned int state, v;
 136     int val, n;
 137
 138     state = *header_state;
 139     n = *size_ptr;
 140     while (n > 0) {
 141         if (url_feof(pb))
 142             break;
 143         v = get_byte(pb);
 144         n--;
 145         if (state == 0x000001) {
 146             state = ((state << 8) | v) & 0xffffff;
 147             val = state;
 148             goto found;
 149         }
 150         state = ((state << 8) | v) & 0xffffff;
 151     }
 152     val = -1;
 153  found:
 154     *header_state = state;
 155     *size_ptr = n;
 156     return val;
 157 }
 158
 159 #if 0 /* unused, remove? */
 160 /* XXX: optimize */
 161 static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
 162 {
 163     int64_t pos, pos_start;
 164     int max_size, start_code;
 165
 166     max_size = *size_ptr;
 167     pos_start = url_ftell(pb);
 168
 169     /* in order to go faster, we fill the buffer */
 170     pos = pos_start - 16386;
 171     if (pos < 0)
 172         pos = 0;
 173     url_fseek(pb, pos, SEEK_SET);
 174     get_byte(pb);
 175
 176     pos = pos_start;
 177     for(;;) {
 178         pos--;
 179         if (pos < 0 || (pos_start - pos) >= max_size) {
 180             start_code = -1;
 181             goto the_end;
 182         }
 183         url_fseek(pb, pos, SEEK_SET);
 184         start_code = get_be32(pb);
 185         if ((start_code & 0xffffff00) == 0x100)
 186             break;
 187     }
 188  the_end:
 189     *size_ptr = pos_start - pos;
 190     return start_code;
 191 }
 192 #endif
 193
 194 /**
 195  * Extracts stream types from a program stream map
 196  * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
 197  *
 198  * @return number of bytes occupied by PSM in the bitstream
 199  */
 200 static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
 201 {
 202     int psm_length, ps_info_length, es_map_length;
 203
 204     psm_length = get_be16(pb);
 205     get_byte(pb);
 206     get_byte(pb);
 207     ps_info_length = get_be16(pb);
 208
 209     /* skip program_stream_info */
 210     url_fskip(pb, ps_info_length);
 211     es_map_length = get_be16(pb);
 212
 213     /* at least one es available? */
 214     while (es_map_length >= 4){
 215         unsigned char type      = get_byte(pb);
 216         unsigned char es_id     = get_byte(pb);
 217         uint16_t es_info_length = get_be16(pb);
 218         /* remember mapping from stream id to stream type */
 219         m->psm_es_type[es_id] = type;
 220         /* skip program_stream_info */
 221         url_fskip(pb, es_info_length);
 222         es_map_length -= 4 + es_info_length;
 223     }
 224     get_be32(pb); /* crc32 */
 225     return 2 + psm_length;
 226 }
 227
 228 /* read the next PES header. Return its position in ppos
 229    (if not NULL), and its start code, pts and dts.
 230  */
 231 static int mpegps_read_pes_header(AVFormatContext *s,
 232                                   int64_t *ppos, int *pstart_code,
 233                                   int64_t *ppts, int64_t *pdts)
 234 {
 235     MpegDemuxContext *m = s->priv_data;
 236     int len, size, startcode, c, flags, header_len;
 237     int pes_ext, ext2_len, id_ext, skip;
 238     int64_t pts, dts;
 239     int64_t last_sync= url_ftell(s->pb);
 240
 241  error_redo:
 242         url_fseek(s->pb, last_sync, SEEK_SET);
 243  redo:
 244         /* next start code (should be immediately after) */
 245         m->header_state = 0xff;
 246         size = MAX_SYNC_SIZE;
 247         startcode = find_next_start_code(s->pb, &size, &m->header_state);
 248         last_sync = url_ftell(s->pb);
 249     //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(s->pb));
 250     if (startcode < 0)
 251         return AVERROR(EIO);
 252     if (startcode == PACK_START_CODE)
 253         goto redo;
 254     if (startcode == SYSTEM_HEADER_START_CODE)
 255         goto redo;
 256     if (startcode == PADDING_STREAM) {
 257         url_fskip(s->pb, get_be16(s->pb));
 258         goto redo;
 259     }
 260     if (startcode == PRIVATE_STREAM_2) {
 261         len = get_be16(s->pb);
 262         if (!m->sofdec) {
 263             while (len-- >= 6) {
 264                 if (get_byte(s->pb) == 'S') {
 265                     uint8_t buf[5];
 266                     get_buffer(s->pb, buf, sizeof(buf));
 267                     m->sofdec = !memcmp(buf, "ofdec", 5);
 268                     len -= sizeof(buf);
 269                     break;
 270                 }
 271             }
 272             m->sofdec -= !m->sofdec;
 273         }
 274         url_fskip(s->pb, len);
 275         goto redo;
 276     }
 277     if (startcode == PROGRAM_STREAM_MAP) {
 278         mpegps_psm_parse(m, s->pb);
 279         goto redo;
 280     }
 281
 282     /* find matching stream */
 283     if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
 284           (startcode >= 0x1e0 && startcode <= 0x1ef) ||
 285           (startcode == 0x1bd) || (startcode == 0x1fd)))
 286         goto redo;
 287     if (ppos) {
 288         *ppos = url_ftell(s->pb) - 4;
 289     }
 290     len = get_be16(s->pb);
 291     pts =
 292     dts = AV_NOPTS_VALUE;
 293     /* stuffing */
 294     for(;;) {
 295         if (len < 1)
 296             goto error_redo;
 297         c = get_byte(s->pb);
 298         len--;
 299         /* XXX: for mpeg1, should test only bit 7 */
 300         if (c != 0xff)
 301             break;
 302     }
 303     if ((c & 0xc0) == 0x40) {
 304         /* buffer scale & size */
 305         get_byte(s->pb);
 306         c = get_byte(s->pb);
 307         len -= 2;
 308     }
 309     if ((c & 0xe0) == 0x20) {
 310         dts = pts = get_pts(s->pb, c);
 311         len -= 4;
 312         if (c & 0x10){
 313             dts = get_pts(s->pb, -1);
 314             len -= 5;
 315         }
 316     } else if ((c & 0xc0) == 0x80) {
 317         /* mpeg 2 PES */
 318 #if 0 /* some streams have this field set for no apparent reason */
 319         if ((c & 0x30) != 0) {
 320             /* Encrypted multiplex not handled */
 321             goto redo;
 322         }
 323 #endif
 324         flags = get_byte(s->pb);
 325         header_len = get_byte(s->pb);
 326         len -= 2;
 327         if (header_len > len)
 328             goto error_redo;
 329         len -= header_len;
 330         if (flags & 0x80) {
 331             dts = pts = get_pts(s->pb, -1);
 332             header_len -= 5;
 333             if (flags & 0x40) {
 334                 dts = get_pts(s->pb, -1);
 335                 header_len -= 5;
 336             }
 337         }
 338         if (flags & 0x3f && header_len == 0){
 339             flags &= 0xC0;
 340             av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");
 341         }
 342         if (flags & 0x01) { /* PES extension */
 343             pes_ext = get_byte(s->pb);
 344             header_len--;
 345             /* Skip PES private data, program packet sequence counter and P-STD buffer */
 346             skip = (pes_ext >> 4) & 0xb;
 347             skip += skip & 0x9;
 348             if (pes_ext & 0x40 || skip > header_len){
 349                 av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);
 350                 pes_ext=skip=0;
 351             }
 352             url_fskip(s->pb, skip);
 353             header_len -= skip;
 354
 355             if (pes_ext & 0x01) { /* PES extension 2 */
 356                 ext2_len = get_byte(s->pb);
 357                 header_len--;
 358                 if ((ext2_len & 0x7f) > 0) {
 359                     id_ext = get_byte(s->pb);
 360                     if ((id_ext & 0x80) == 0)
 361                         startcode = ((startcode & 0xff) << 8) | id_ext;
 362                     header_len--;
 363                 }
 364             }
 365         }
 366         if(header_len < 0)
 367             goto error_redo;
 368         url_fskip(s->pb, header_len);
 369     }
 370     else if( c!= 0xf )
 371         goto redo;
 372
 373     if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
 374         startcode = get_byte(s->pb);
 375         len--;
 376         if (startcode >= 0x80 && startcode <= 0xcf) {
 377             /* audio: skip header */
 378             get_byte(s->pb);
 379             get_byte(s->pb);
 380             get_byte(s->pb);
 381             len -= 3;
 382             if (startcode >= 0xb0 && startcode <= 0xbf) {
 383                 /* MLP/TrueHD audio has a 4-byte header */
 384                 get_byte(s->pb);
 385                 len--;
 386             }
 387         }
 388     }
 389     if(len<0)
 390         goto error_redo;
 391     if(dts != AV_NOPTS_VALUE && ppos){
 392         int i;
 393         for(i=0; i<s->nb_streams; i++){
 394             if(startcode == s->streams[i]->id &&
 395                !url_is_streamed(s->pb) /* index useless on streams anyway */) {
 396                 ff_reduce_index(s, i);
 397                 av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
 398             }
 399         }
 400     }
 401
 402     *pstart_code = startcode;
 403     *ppts = pts;
 404     *pdts = dts;
 405     return len;
 406 }
 407
 408 static int mpegps_read_packet(AVFormatContext *s,
 409                               AVPacket *pkt)
 410 {
 411     MpegDemuxContext *m = s->priv_data;
 412     AVStream *st;
 413     int len, startcode, i, es_type;
 414     enum CodecID codec_id = CODEC_ID_NONE;
 415     enum CodecType type;
 416     int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
 417     uint8_t av_uninit(dvdaudio_substream_type);
 418
 419  redo:
 420     len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
 421     if (len < 0)
 422         return len;
 423
 424     if(startcode == 0x1bd) {
 425         dvdaudio_substream_type = get_byte(s->pb);
 426         url_fskip(s->pb, 3);
 427         len -= 4;
 428     }
 429
 430     /* now find stream */
 431     for(i=0;i<s->nb_streams;i++) {
 432         st = s->streams[i];
 433         if (st->id == startcode)
 434             goto found;
 435     }
 436
 437     es_type = m->psm_es_type[startcode & 0xff];
 438     if(es_type > 0 && es_type != STREAM_TYPE_PRIVATE_DATA){
 439         if(es_type == STREAM_TYPE_VIDEO_MPEG1){
 440             codec_id = CODEC_ID_MPEG2VIDEO;
 441             type = CODEC_TYPE_VIDEO;
 442         } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
 443             codec_id = CODEC_ID_MPEG2VIDEO;
 444             type = CODEC_TYPE_VIDEO;
 445         } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
 446                   es_type == STREAM_TYPE_AUDIO_MPEG2){
 447             codec_id = CODEC_ID_MP3;
 448             type = CODEC_TYPE_AUDIO;
 449         } else if(es_type == STREAM_TYPE_AUDIO_AAC){
 450             codec_id = CODEC_ID_AAC;
 451             type = CODEC_TYPE_AUDIO;
 452         } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
 453             codec_id = CODEC_ID_MPEG4;
 454             type = CODEC_TYPE_VIDEO;
 455         } else if(es_type == STREAM_TYPE_VIDEO_H264){
 456             codec_id = CODEC_ID_H264;
 457             type = CODEC_TYPE_VIDEO;
 458         } else if(es_type == STREAM_TYPE_AUDIO_AC3){
 459             codec_id = CODEC_ID_AC3;
 460             type = CODEC_TYPE_AUDIO;
 461         } else {
 462             goto skip;
 463         }
 464     } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
 465         static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
 466         unsigned char buf[8];
 467         get_buffer(s->pb, buf, 8);
 468         url_fseek(s->pb, -8, SEEK_CUR);
 469         if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
 470             codec_id = CODEC_ID_CAVS;
 471         else
 472             codec_id = CODEC_ID_PROBE;
 473         type = CODEC_TYPE_VIDEO;
 474     } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
 475         type = CODEC_TYPE_AUDIO;
 476         codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
 477     } else if (startcode >= 0x80 && startcode <= 0x87) {
 478         type = CODEC_TYPE_AUDIO;
 479         codec_id = CODEC_ID_AC3;
 480     } else if (  ( startcode >= 0x88 && startcode <= 0x8f)
 481                ||( startcode >= 0x98 && startcode <= 0x9f)) {
 482         /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
 483         type = CODEC_TYPE_AUDIO;
 484         codec_id = CODEC_ID_DTS;
 485     } else if (startcode >= 0xa0 && startcode <= 0xaf) {
 486         type = CODEC_TYPE_AUDIO;
 487         /* 16 bit form will be handled as CODEC_ID_PCM_S16BE */
 488         codec_id = CODEC_ID_PCM_DVD;
 489     } else if (startcode >= 0xb0 && startcode <= 0xbf) {
 490         type = CODEC_TYPE_AUDIO;
 491         codec_id = CODEC_ID_TRUEHD;
 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 if (startcode == 0x1bd) {
 503         // check dvd audio substream type
 504         type = CODEC_TYPE_AUDIO;
 505         switch(dvdaudio_substream_type & 0xe0) {
 506         case 0xa0:  codec_id = CODEC_ID_PCM_DVD;
 507                     break;
 508         case 0x80:  if((dvdaudio_substream_type & 0xf8) == 0x88)
 509                          codec_id = CODEC_ID_DTS;
 510                     else codec_id = CODEC_ID_AC3;
 511                     break;
 512         default:    av_log(s, AV_LOG_ERROR, "Unknown 0x1bd sub-stream\n");
 513                     goto skip;
 514         }
 515     } else {
 516     skip:
 517         /* skip packet */
 518         url_fskip(s->pb, len);
 519         goto redo;
 520     }
 521     /* no stream found: add a new stream */
 522     st = av_new_stream(s, startcode);
 523     if (!st)
 524         goto skip;
 525     st->codec->codec_type = type;
 526     st->codec->codec_id = codec_id;
 527     if (codec_id != CODEC_ID_PCM_S16BE)
 528         st->need_parsing = AVSTREAM_PARSE_FULL;
 529  found:
 530     if(st->discard >= AVDISCARD_ALL)
 531         goto skip;
 532     if ((startcode >= 0xa0 && startcode <= 0xaf) ||
 533         (startcode == 0x1bd && ((dvdaudio_substream_type & 0xe0) == 0xa0))) {
 534         int b1, freq;
 535
 536         /* for LPCM, we just skip the header and consider it is raw
 537            audio data */
 538         if (len <= 3)
 539             goto skip;
 540         get_byte(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
 541         b1 = get_byte(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
 542         get_byte(s->pb); /* dynamic range control (0x80 = off) */
 543         len -= 3;
 544         freq = (b1 >> 4) & 3;
 545         st->codec->sample_rate = lpcm_freq_tab[freq];
 546         st->codec->channels = 1 + (b1 & 7);
 547         st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;
 548         st->codec->bit_rate = st->codec->channels *
 549                               st->codec->sample_rate *
 550                               st->codec->bits_per_coded_sample;
 551         if (st->codec->bits_per_coded_sample == 16)
 552             st->codec->codec_id = CODEC_ID_PCM_S16BE;
 553         else if (st->codec->bits_per_coded_sample == 28)
 554             return AVERROR(EINVAL);
 555     }
 556     av_new_packet(pkt, len);
 557     get_buffer(s->pb, pkt->data, pkt->size);
 558     pkt->pts = pts;
 559     pkt->dts = dts;
 560     pkt->stream_index = st->index;
 561 #if 0
 562     av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
 563            pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
 564 #endif
 565
 566     return 0;
 567 }
 568
 569 static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
 570                                int64_t *ppos, int64_t pos_limit)
 571 {
 572     int len, startcode;
 573     int64_t pos, pts, dts;
 574
 575     pos = *ppos;
 576 #ifdef DEBUG_SEEK
 577     printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
 578 #endif
 579     if (url_fseek(s->pb, pos, SEEK_SET) < 0)
 580         return AV_NOPTS_VALUE;
 581
 582     for(;;) {
 583         len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
 584         if (len < 0) {
 585 #ifdef DEBUG_SEEK
 586             printf("none (ret=%d)\n", len);
 587 #endif
 588             return AV_NOPTS_VALUE;
 589         }
 590         if (startcode == s->streams[stream_index]->id &&
 591             dts != AV_NOPTS_VALUE) {
 592             break;
 593         }
 594         url_fskip(s->pb, len);
 595     }
 596 #ifdef DEBUG_SEEK
 597     printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
 598 #endif
 599     *ppos = pos;
 600     return dts;
 601 }
 602
 603 AVInputFormat mpegps_demuxer = {
 604     "mpeg",
 605     NULL_IF_CONFIG_SMALL("MPEG-PS format"),
 606     sizeof(MpegDemuxContext),
 607     mpegps_probe,
 608     mpegps_read_header,
 609     mpegps_read_packet,
 610     NULL,
 611     NULL, //mpegps_read_seek,
 612     mpegps_read_dts,
 613     .flags = AVFMT_SHOW_IDS|AVFMT_TS_DISCONT,
 614 };