libavformat/mpeg.c

   1 /*
   2  * MPEG1/2 demuxer
   3  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 "internal.h"
  24 #include "mpeg.h"
  25
  26 #undef NDEBUG
  27 #include <assert.h>
  28
  29 /*********************************************/
  30 /* demux code */
  31
  32 #define MAX_SYNC_SIZE 100000
  33
  34 static int check_pes(uint8_t *p, uint8_t *end){
  35     int pes1;
  36     int pes2=      (p[3] & 0xC0) == 0x80
  37                 && (p[4] & 0xC0) != 0x40
  38                 &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));
  39
  40     for(p+=3; p<end && *p == 0xFF; p++);
  41     if((*p&0xC0) == 0x40) p+=2;
  42     if((*p&0xF0) == 0x20){
  43         pes1= p[0]&p[2]&p[4]&1;
  44     }else if((*p&0xF0) == 0x30){
  45         pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
  46     }else
  47         pes1 = *p == 0x0F;
  48
  49     return pes1||pes2;
  50 }
  51
  52 static int check_pack_header(const uint8_t *buf) {
  53     return (buf[1] & 0xC0) == 0x40 || (buf[1] & 0xF0) == 0x20;
  54 }
  55
  56 static int mpegps_probe(AVProbeData *p)
  57 {
  58     uint32_t code= -1;
  59     int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
  60     int i;
  61     int score=0;
  62
  63     for(i=0; i<p->buf_size; i++){
  64         code = (code<<8) + p->buf[i];
  65         if ((code & 0xffffff00) == 0x100) {
  66             int len= p->buf[i+1] << 8 | p->buf[i+2];
  67             int pes= check_pes(p->buf+i, p->buf+p->buf_size);
  68             int pack = check_pack_header(p->buf+i);
  69
  70             if(code == SYSTEM_HEADER_START_CODE) sys++;
  71             else if(code == PACK_START_CODE && pack) pspack++;
  72             else if((code & 0xf0) == VIDEO_ID &&  pes) vid++;
  73             // skip pes payload to avoid start code emulation for private
  74             // and audio streams
  75             else if((code & 0xe0) == AUDIO_ID &&  pes) {audio++; i+=len;}
  76             else if(code == PRIVATE_STREAM_1  &&  pes) {priv1++; i+=len;}
  77
  78             else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
  79             else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
  80             else if(code == PRIVATE_STREAM_1  && !pes) invalid++;
  81         }
  82     }
  83
  84     if(vid+audio > invalid)     /* invalid VDR files nd short PES streams */
  85         score= AVPROBE_SCORE_MAX/4;
  86
  87     if(sys>invalid && sys*9 <= pspack*10)
  88         return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
  89     if(pspack > invalid && (priv1+vid+audio)*10 >= pspack*9)
  90         return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
  91     if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */
  92         return (audio > 12 || vid > 3) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4;
  93
  94     //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
  95     //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6
  96     return score;
  97 }
  98
  99
 100 typedef struct MpegDemuxContext {
 101     int32_t header_state;
 102     unsigned char psm_es_type[256];
 103     int sofdec;
 104 } MpegDemuxContext;
 105
 106 static int mpegps_read_header(AVFormatContext *s)
 107 {
 108     MpegDemuxContext *m = s->priv_data;
 109     const char *sofdec = "Sofdec";
 110     int v, i = 0;
 111
 112     m->header_state = 0xff;
 113     s->ctx_flags |= AVFMTCTX_NOHEADER;
 114
 115     m->sofdec = -1;
 116     do {
 117         v = avio_r8(s->pb);
 118         m->header_state = m->header_state << 8 | v;
 119         m->sofdec++;
 120     } while (v == sofdec[i] && i++ < 6);
 121
 122     m->sofdec = (m->sofdec == 6) ? 1 : 0;
 123
 124     /* no need to do more */
 125     return 0;
 126 }
 127
 128 static int64_t get_pts(AVIOContext *pb, int c)
 129 {
 130     uint8_t buf[5];
 131
 132     buf[0] = c<0 ? avio_r8(pb) : c;
 133     avio_read(pb, buf+1, 4);
 134
 135     return ff_parse_pes_pts(buf);
 136 }
 137
 138 static int find_next_start_code(AVIOContext *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 (pb->eof_reached)
 148             break;
 149         v = avio_r8(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 /**
 166  * Extract stream types from a program stream map
 167  * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
 168  *
 169  * @return number of bytes occupied by PSM in the bitstream
 170  */
 171 static long mpegps_psm_parse(MpegDemuxContext *m, AVIOContext *pb)
 172 {
 173     int psm_length, ps_info_length, es_map_length;
 174
 175     psm_length = avio_rb16(pb);
 176     avio_r8(pb);
 177     avio_r8(pb);
 178     ps_info_length = avio_rb16(pb);
 179
 180     /* skip program_stream_info */
 181     avio_skip(pb, ps_info_length);
 182     es_map_length = avio_rb16(pb);
 183
 184     /* at least one es available? */
 185     while (es_map_length >= 4){
 186         unsigned char type      = avio_r8(pb);
 187         unsigned char es_id     = avio_r8(pb);
 188         uint16_t es_info_length = avio_rb16(pb);
 189         /* remember mapping from stream id to stream type */
 190         m->psm_es_type[es_id] = type;
 191         /* skip program_stream_info */
 192         avio_skip(pb, es_info_length);
 193         es_map_length -= 4 + es_info_length;
 194     }
 195     avio_rb32(pb); /* crc32 */
 196     return 2 + psm_length;
 197 }
 198
 199 /* read the next PES header. Return its position in ppos
 200    (if not NULL), and its start code, pts and dts.
 201  */
 202 static int mpegps_read_pes_header(AVFormatContext *s,
 203                                   int64_t *ppos, int *pstart_code,
 204                                   int64_t *ppts, int64_t *pdts)
 205 {
 206     MpegDemuxContext *m = s->priv_data;
 207     int len, size, startcode, c, flags, header_len;
 208     int pes_ext, ext2_len, id_ext, skip;
 209     int64_t pts, dts;
 210     int64_t last_sync= avio_tell(s->pb);
 211
 212  error_redo:
 213         avio_seek(s->pb, last_sync, SEEK_SET);
 214  redo:
 215         /* next start code (should be immediately after) */
 216         m->header_state = 0xff;
 217         size = MAX_SYNC_SIZE;
 218         startcode = find_next_start_code(s->pb, &size, &m->header_state);
 219         last_sync = avio_tell(s->pb);
 220     if (startcode < 0){
 221         if(s->pb->eof_reached)
 222             return AVERROR_EOF;
 223         //FIXME we should remember header_state
 224         return AVERROR(EAGAIN);
 225     }
 226
 227     if (startcode == PACK_START_CODE)
 228         goto redo;
 229     if (startcode == SYSTEM_HEADER_START_CODE)
 230         goto redo;
 231     if (startcode == PADDING_STREAM) {
 232         avio_skip(s->pb, avio_rb16(s->pb));
 233         goto redo;
 234     }
 235     if (startcode == PRIVATE_STREAM_2) {
 236         len = avio_rb16(s->pb);
 237         if (!m->sofdec) {
 238             while (len-- >= 6) {
 239                 if (avio_r8(s->pb) == 'S') {
 240                     uint8_t buf[5];
 241                     avio_read(s->pb, buf, sizeof(buf));
 242                     m->sofdec = !memcmp(buf, "ofdec", 5);
 243                     len -= sizeof(buf);
 244                     break;
 245                 }
 246             }
 247             m->sofdec -= !m->sofdec;
 248         }
 249         avio_skip(s->pb, len);
 250         goto redo;
 251     }
 252     if (startcode == PROGRAM_STREAM_MAP) {
 253         mpegps_psm_parse(m, s->pb);
 254         goto redo;
 255     }
 256
 257     /* find matching stream */
 258     if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
 259           (startcode >= 0x1e0 && startcode <= 0x1ef) ||
 260           (startcode == 0x1bd) || (startcode == 0x1fd)))
 261         goto redo;
 262     if (ppos) {
 263         *ppos = avio_tell(s->pb) - 4;
 264     }
 265     len = avio_rb16(s->pb);
 266     pts =
 267     dts = AV_NOPTS_VALUE;
 268     /* stuffing */
 269     for(;;) {
 270         if (len < 1)
 271             goto error_redo;
 272         c = avio_r8(s->pb);
 273         len--;
 274         /* XXX: for mpeg1, should test only bit 7 */
 275         if (c != 0xff)
 276             break;
 277     }
 278     if ((c & 0xc0) == 0x40) {
 279         /* buffer scale & size */
 280         avio_r8(s->pb);
 281         c = avio_r8(s->pb);
 282         len -= 2;
 283     }
 284     if ((c & 0xe0) == 0x20) {
 285         dts = pts = get_pts(s->pb, c);
 286         len -= 4;
 287         if (c & 0x10){
 288             dts = get_pts(s->pb, -1);
 289             len -= 5;
 290         }
 291     } else if ((c & 0xc0) == 0x80) {
 292         /* mpeg 2 PES */
 293         flags = avio_r8(s->pb);
 294         header_len = avio_r8(s->pb);
 295         len -= 2;
 296         if (header_len > len)
 297             goto error_redo;
 298         len -= header_len;
 299         if (flags & 0x80) {
 300             dts = pts = get_pts(s->pb, -1);
 301             header_len -= 5;
 302             if (flags & 0x40) {
 303                 dts = get_pts(s->pb, -1);
 304                 header_len -= 5;
 305             }
 306         }
 307         if (flags & 0x3f && header_len == 0){
 308             flags &= 0xC0;
 309             av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");
 310         }
 311         if (flags & 0x01) { /* PES extension */
 312             pes_ext = avio_r8(s->pb);
 313             header_len--;
 314             /* Skip PES private data, program packet sequence counter and P-STD buffer */
 315             skip = (pes_ext >> 4) & 0xb;
 316             skip += skip & 0x9;
 317             if (pes_ext & 0x40 || skip > header_len){
 318                 av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);
 319                 pes_ext=skip=0;
 320             }
 321             avio_skip(s->pb, skip);
 322             header_len -= skip;
 323
 324             if (pes_ext & 0x01) { /* PES extension 2 */
 325                 ext2_len = avio_r8(s->pb);
 326                 header_len--;
 327                 if ((ext2_len & 0x7f) > 0) {
 328                     id_ext = avio_r8(s->pb);
 329                     if ((id_ext & 0x80) == 0)
 330                         startcode = ((startcode & 0xff) << 8) | id_ext;
 331                     header_len--;
 332                 }
 333             }
 334         }
 335         if(header_len < 0)
 336             goto error_redo;
 337         avio_skip(s->pb, header_len);
 338     }
 339     else if( c!= 0xf )
 340         goto redo;
 341
 342     if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
 343         startcode = avio_r8(s->pb);
 344         len--;
 345         if (startcode >= 0x80 && startcode <= 0xcf) {
 346             /* audio: skip header */
 347             avio_r8(s->pb);
 348             avio_r8(s->pb);
 349             avio_r8(s->pb);
 350             len -= 3;
 351             if (startcode >= 0xb0 && startcode <= 0xbf) {
 352                 /* MLP/TrueHD audio has a 4-byte header */
 353                 avio_r8(s->pb);
 354                 len--;
 355             }
 356         }
 357     }
 358     if(len<0)
 359         goto error_redo;
 360     if(dts != AV_NOPTS_VALUE && ppos){
 361         int i;
 362         for(i=0; i<s->nb_streams; i++){
 363             if(startcode == s->streams[i]->id &&
 364                s->pb->seekable /* index useless on streams anyway */) {
 365                 ff_reduce_index(s, i);
 366                 av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
 367             }
 368         }
 369     }
 370
 371     *pstart_code = startcode;
 372     *ppts = pts;
 373     *pdts = dts;
 374     return len;
 375 }
 376
 377 static int mpegps_read_packet(AVFormatContext *s,
 378                               AVPacket *pkt)
 379 {
 380     MpegDemuxContext *m = s->priv_data;
 381     AVStream *st;
 382     int len, startcode, i, es_type, ret;
 383     enum AVCodecID codec_id = AV_CODEC_ID_NONE;
 384     enum AVMediaType type;
 385     int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
 386     uint8_t av_uninit(dvdaudio_substream_type);
 387
 388  redo:
 389     len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
 390     if (len < 0)
 391         return len;
 392
 393     if(startcode == 0x1bd) {
 394         dvdaudio_substream_type = avio_r8(s->pb);
 395         avio_skip(s->pb, 3);
 396         len -= 4;
 397     }
 398
 399     /* now find stream */
 400     for(i=0;i<s->nb_streams;i++) {
 401         st = s->streams[i];
 402         if (st->id == startcode)
 403             goto found;
 404     }
 405
 406     es_type = m->psm_es_type[startcode & 0xff];
 407     if(es_type > 0 && es_type != STREAM_TYPE_PRIVATE_DATA){
 408         if(es_type == STREAM_TYPE_VIDEO_MPEG1){
 409             codec_id = AV_CODEC_ID_MPEG2VIDEO;
 410             type = AVMEDIA_TYPE_VIDEO;
 411         } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
 412             codec_id = AV_CODEC_ID_MPEG2VIDEO;
 413             type = AVMEDIA_TYPE_VIDEO;
 414         } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
 415                   es_type == STREAM_TYPE_AUDIO_MPEG2){
 416             codec_id = AV_CODEC_ID_MP3;
 417             type = AVMEDIA_TYPE_AUDIO;
 418         } else if(es_type == STREAM_TYPE_AUDIO_AAC){
 419             codec_id = AV_CODEC_ID_AAC;
 420             type = AVMEDIA_TYPE_AUDIO;
 421         } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
 422             codec_id = AV_CODEC_ID_MPEG4;
 423             type = AVMEDIA_TYPE_VIDEO;
 424         } else if(es_type == STREAM_TYPE_VIDEO_H264){
 425             codec_id = AV_CODEC_ID_H264;
 426             type = AVMEDIA_TYPE_VIDEO;
 427         } else if(es_type == STREAM_TYPE_AUDIO_AC3){
 428             codec_id = AV_CODEC_ID_AC3;
 429             type = AVMEDIA_TYPE_AUDIO;
 430         } else {
 431             goto skip;
 432         }
 433     } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
 434         static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
 435         unsigned char buf[8];
 436         avio_read(s->pb, buf, 8);
 437         avio_seek(s->pb, -8, SEEK_CUR);
 438         if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
 439             codec_id = AV_CODEC_ID_CAVS;
 440         else
 441             codec_id = AV_CODEC_ID_PROBE;
 442         type = AVMEDIA_TYPE_VIDEO;
 443     } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
 444         type = AVMEDIA_TYPE_AUDIO;
 445         codec_id = m->sofdec > 0 ? AV_CODEC_ID_ADPCM_ADX : AV_CODEC_ID_MP2;
 446     } else if (startcode >= 0x80 && startcode <= 0x87) {
 447         type = AVMEDIA_TYPE_AUDIO;
 448         codec_id = AV_CODEC_ID_AC3;
 449     } else if (  ( startcode >= 0x88 && startcode <= 0x8f)
 450                ||( startcode >= 0x98 && startcode <= 0x9f)) {
 451         /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
 452         type = AVMEDIA_TYPE_AUDIO;
 453         codec_id = AV_CODEC_ID_DTS;
 454     } else if (startcode >= 0xa0 && startcode <= 0xaf) {
 455         type = AVMEDIA_TYPE_AUDIO;
 456         /* 16 bit form will be handled as AV_CODEC_ID_PCM_S16BE */
 457         codec_id = AV_CODEC_ID_PCM_DVD;
 458     } else if (startcode >= 0xb0 && startcode <= 0xbf) {
 459         type = AVMEDIA_TYPE_AUDIO;
 460         codec_id = AV_CODEC_ID_TRUEHD;
 461     } else if (startcode >= 0xc0 && startcode <= 0xcf) {
 462         /* Used for both AC-3 and E-AC-3 in EVOB files */
 463         type = AVMEDIA_TYPE_AUDIO;
 464         codec_id = AV_CODEC_ID_AC3;
 465     } else if (startcode >= 0x20 && startcode <= 0x3f) {
 466         type = AVMEDIA_TYPE_SUBTITLE;
 467         codec_id = AV_CODEC_ID_DVD_SUBTITLE;
 468     } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
 469         type = AVMEDIA_TYPE_VIDEO;
 470         codec_id = AV_CODEC_ID_VC1;
 471     } else if (startcode == 0x1bd) {
 472         // check dvd audio substream type
 473         type = AVMEDIA_TYPE_AUDIO;
 474         switch(dvdaudio_substream_type & 0xe0) {
 475         case 0xa0:  codec_id = AV_CODEC_ID_PCM_DVD;
 476                     break;
 477         case 0x80:  if((dvdaudio_substream_type & 0xf8) == 0x88)
 478                          codec_id = AV_CODEC_ID_DTS;
 479                     else codec_id = AV_CODEC_ID_AC3;
 480                     break;
 481         default:    av_log(s, AV_LOG_ERROR, "Unknown 0x1bd sub-stream\n");
 482                     goto skip;
 483         }
 484     } else {
 485     skip:
 486         /* skip packet */
 487         avio_skip(s->pb, len);
 488         goto redo;
 489     }
 490     /* no stream found: add a new stream */
 491     st = avformat_new_stream(s, NULL);
 492     if (!st)
 493         goto skip;
 494     st->id = startcode;
 495     st->codec->codec_type = type;
 496     st->codec->codec_id = codec_id;
 497     if (codec_id != AV_CODEC_ID_PCM_S16BE)
 498         st->need_parsing = AVSTREAM_PARSE_FULL;
 499  found:
 500     if(st->discard >= AVDISCARD_ALL)
 501         goto skip;
 502     if ((startcode >= 0xa0 && startcode <= 0xaf) ||
 503         (startcode == 0x1bd && ((dvdaudio_substream_type & 0xe0) == 0xa0))) {
 504         int b1, freq;
 505
 506         /* for LPCM, we just skip the header and consider it is raw
 507            audio data */
 508         if (len <= 3)
 509             goto skip;
 510         avio_r8(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
 511         b1 = avio_r8(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
 512         avio_r8(s->pb); /* dynamic range control (0x80 = off) */
 513         len -= 3;
 514         freq = (b1 >> 4) & 3;
 515         st->codec->sample_rate = lpcm_freq_tab[freq];
 516         st->codec->channels = 1 + (b1 & 7);
 517         st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;
 518         st->codec->bit_rate = st->codec->channels *
 519                               st->codec->sample_rate *
 520                               st->codec->bits_per_coded_sample;
 521         if (st->codec->bits_per_coded_sample == 16)
 522             st->codec->codec_id = AV_CODEC_ID_PCM_S16BE;
 523         else if (st->codec->bits_per_coded_sample == 28)
 524             return AVERROR(EINVAL);
 525     }
 526     ret = av_get_packet(s->pb, pkt, len);
 527     pkt->pts = pts;
 528     pkt->dts = dts;
 529     pkt->pos = dummy_pos;
 530     pkt->stream_index = st->index;
 531     av_dlog(s, "%d: pts=%0.3f dts=%0.3f size=%d\n",
 532             pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0,
 533             pkt->size);
 534
 535     return (ret < 0) ? ret : 0;
 536 }
 537
 538 static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
 539                                int64_t *ppos, int64_t pos_limit)
 540 {
 541     int len, startcode;
 542     int64_t pos, pts, dts;
 543
 544     pos = *ppos;
 545     if (avio_seek(s->pb, pos, SEEK_SET) < 0)
 546         return AV_NOPTS_VALUE;
 547
 548     for(;;) {
 549         len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
 550         if (len < 0) {
 551             av_dlog(s, "none (ret=%d)\n", len);
 552             return AV_NOPTS_VALUE;
 553         }
 554         if (startcode == s->streams[stream_index]->id &&
 555             dts != AV_NOPTS_VALUE) {
 556             break;
 557         }
 558         avio_skip(s->pb, len);
 559     }
 560     av_dlog(s, "pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n",
 561             pos, dts, dts / 90000.0);
 562     *ppos = pos;
 563     return dts;
 564 }
 565
 566 AVInputFormat ff_mpegps_demuxer = {
 567     .name           = "mpeg",
 568     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-PS (MPEG-2 Program Stream)"),
 569     .priv_data_size = sizeof(MpegDemuxContext),
 570     .read_probe     = mpegps_probe,
 571     .read_header    = mpegps_read_header,
 572     .read_packet    = mpegps_read_packet,
 573     .read_timestamp = mpegps_read_dts,
 574     .flags          = AVFMT_SHOW_IDS | AVFMT_TS_DISCONT,
 575 };