FFmpeg: libavformat/mpeg.c Source File

00001 /*
00002  * MPEG1/2 demuxer
00003  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "avformat.h"
00023 #include "internal.h"
00024 #include "mpeg.h"
00025 
00026 #undef NDEBUG
00027 #include <assert.h>
00028 
00029 /*********************************************/
00030 /* demux code */
00031 
00032 #define MAX_SYNC_SIZE 100000
00033 
00034 static int check_pes(uint8_t *p, uint8_t *end){
00035     int pes1;
00036     int pes2=      (p[3] & 0xC0) == 0x80
00037                 && (p[4] & 0xC0) != 0x40
00038                 &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));
00039 
00040     for(p+=3; p<end && *p == 0xFF; p++);
00041     if((*p&0xC0) == 0x40) p+=2;
00042     if((*p&0xF0) == 0x20){
00043         pes1= p[0]&p[2]&p[4]&1;
00044     }else if((*p&0xF0) == 0x30){
00045         pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
00046     }else
00047         pes1 = *p == 0x0F;
00048 
00049     return pes1||pes2;
00050 }
00051 
00052 static int check_pack_header(const uint8_t *buf) {
00053     return (buf[1] & 0xC0) == 0x40 || (buf[1] & 0xF0) == 0x20;
00054 }
00055 
00056 static int mpegps_probe(AVProbeData *p)
00057 {
00058     uint32_t code= -1;
00059     int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
00060     int i;
00061     int score=0;
00062 
00063     for(i=0; i<p->buf_size; i++){
00064         code = (code<<8) + p->buf[i];
00065         if ((code & 0xffffff00) == 0x100) {
00066             int len= p->buf[i+1] << 8 | p->buf[i+2];
00067             int pes= check_pes(p->buf+i, p->buf+p->buf_size);
00068             int pack = check_pack_header(p->buf+i);
00069 
00070             if(code == SYSTEM_HEADER_START_CODE) sys++;
00071             else if(code == PACK_START_CODE && pack) pspack++;
00072             else if((code & 0xf0) == VIDEO_ID &&  pes) vid++;
00073             // skip pes payload to avoid start code emulation for private
00074             // and audio streams
00075             else if((code & 0xe0) == AUDIO_ID &&  pes) {audio++; i+=len;}
00076             else if(code == PRIVATE_STREAM_1  &&  pes) {priv1++; i+=len;}
00077             else if(code == 0x1fd             &&  pes) vid++; //VC1
00078 
00079             else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
00080             else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
00081             else if(code == PRIVATE_STREAM_1  && !pes) invalid++;
00082         }
00083     }
00084 
00085     if(vid+audio > invalid+1)     /* invalid VDR files nd short PES streams */
00086         score= AVPROBE_SCORE_MAX/4;
00087 
00088 //av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, invalid, p->buf_size);
00089     if(sys>invalid && sys*9 <= pspack*10)
00090         return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
00091     if(pspack > invalid && (priv1+vid+audio)*10 >= pspack*9)
00092         return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
00093     if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */
00094         return (audio > 12 || vid > 3) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4;
00095 
00096     //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
00097     //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6
00098     return score;
00099 }
00100 
00101 
00102 typedef struct MpegDemuxContext {
00103     int32_t header_state;
00104     unsigned char psm_es_type[256];
00105     int sofdec;
00106 } MpegDemuxContext;
00107 
00108 static int mpegps_read_header(AVFormatContext *s)
00109 {
00110     MpegDemuxContext *m = s->priv_data;
00111     const char *sofdec = "Sofdec";
00112     int v, i = 0;
00113     int64_t last_pos = avio_tell(s->pb);
00114 
00115     m->header_state = 0xff;
00116     s->ctx_flags |= AVFMTCTX_NOHEADER;
00117 
00118     m->sofdec = -1;
00119     do {
00120         v = avio_r8(s->pb);
00121         m->sofdec++;
00122     } while (v == sofdec[i] && i++ < 6);
00123 
00124     m->sofdec = (m->sofdec == 6) ? 1 : 0;
00125 
00126     if (!m->sofdec)
00127        avio_seek(s->pb, last_pos, SEEK_SET);
00128 
00129     /* no need to do more */
00130     return 0;
00131 }
00132 
00133 static int64_t get_pts(AVIOContext *pb, int c)
00134 {
00135     uint8_t buf[5];
00136 
00137     buf[0] = c<0 ? avio_r8(pb) : c;
00138     avio_read(pb, buf+1, 4);
00139 
00140     return ff_parse_pes_pts(buf);
00141 }
00142 
00143 static int find_next_start_code(AVIOContext *pb, int *size_ptr,
00144                                 int32_t *header_state)
00145 {
00146     unsigned int state, v;
00147     int val, n;
00148 
00149     state = *header_state;
00150     n = *size_ptr;
00151     while (n > 0) {
00152         if (url_feof(pb))
00153             break;
00154         v = avio_r8(pb);
00155         n--;
00156         if (state == 0x000001) {
00157             state = ((state << 8) | v) & 0xffffff;
00158             val = state;
00159             goto found;
00160         }
00161         state = ((state << 8) | v) & 0xffffff;
00162     }
00163     val = -1;
00164  found:
00165     *header_state = state;
00166     *size_ptr = n;
00167     return val;
00168 }
00169 
00170 #if 0 /* unused, remove? */
00171 /* XXX: optimize */
00172 static int find_prev_start_code(AVIOContext *pb, int *size_ptr)
00173 {
00174     int64_t pos, pos_start;
00175     int max_size, start_code;
00176 
00177     max_size = *size_ptr;
00178     pos_start = avio_tell(pb);
00179 
00180     /* in order to go faster, we fill the buffer */
00181     pos = pos_start - 16386;
00182     if (pos < 0)
00183         pos = 0;
00184     avio_seek(pb, pos, SEEK_SET);
00185     avio_r8(pb);
00186 
00187     pos = pos_start;
00188     for(;;) {
00189         pos--;
00190         if (pos < 0 || (pos_start - pos) >= max_size) {
00191             start_code = -1;
00192             goto the_end;
00193         }
00194         avio_seek(pb, pos, SEEK_SET);
00195         start_code = avio_rb32(pb);
00196         if ((start_code & 0xffffff00) == 0x100)
00197             break;
00198     }
00199  the_end:
00200     *size_ptr = pos_start - pos;
00201     return start_code;
00202 }
00203 #endif
00204 
00211 static long mpegps_psm_parse(MpegDemuxContext *m, AVIOContext *pb)
00212 {
00213     int psm_length, ps_info_length, es_map_length;
00214 
00215     psm_length = avio_rb16(pb);
00216     avio_r8(pb);
00217     avio_r8(pb);
00218     ps_info_length = avio_rb16(pb);
00219 
00220     /* skip program_stream_info */
00221     avio_skip(pb, ps_info_length);
00222     es_map_length = avio_rb16(pb);
00223 
00224     /* at least one es available? */
00225     while (es_map_length >= 4){
00226         unsigned char type      = avio_r8(pb);
00227         unsigned char es_id     = avio_r8(pb);
00228         uint16_t es_info_length = avio_rb16(pb);
00229         /* remember mapping from stream id to stream type */
00230         m->psm_es_type[es_id] = type;
00231         /* skip program_stream_info */
00232         avio_skip(pb, es_info_length);
00233         es_map_length -= 4 + es_info_length;
00234     }
00235     avio_rb32(pb); /* crc32 */
00236     return 2 + psm_length;
00237 }
00238 
00239 /* read the next PES header. Return its position in ppos
00240    (if not NULL), and its start code, pts and dts.
00241  */
00242 static int mpegps_read_pes_header(AVFormatContext *s,
00243                                   int64_t *ppos, int *pstart_code,
00244                                   int64_t *ppts, int64_t *pdts)
00245 {
00246     MpegDemuxContext *m = s->priv_data;
00247     int len, size, startcode, c, flags, header_len;
00248     int pes_ext, ext2_len, id_ext, skip;
00249     int64_t pts, dts;
00250     int64_t last_sync= avio_tell(s->pb);
00251 
00252  error_redo:
00253         avio_seek(s->pb, last_sync, SEEK_SET);
00254  redo:
00255         /* next start code (should be immediately after) */
00256         m->header_state = 0xff;
00257         size = MAX_SYNC_SIZE;
00258         startcode = find_next_start_code(s->pb, &size, &m->header_state);
00259         last_sync = avio_tell(s->pb);
00260     //printf("startcode=%x pos=0x%"PRIx64"\n", startcode, avio_tell(s->pb));
00261     if (startcode < 0){
00262         if(url_feof(s->pb))
00263             return AVERROR_EOF;
00264         //FIXME we should remember header_state
00265         return AVERROR(EAGAIN);
00266     }
00267 
00268     if (startcode == PACK_START_CODE)
00269         goto redo;
00270     if (startcode == SYSTEM_HEADER_START_CODE)
00271         goto redo;
00272     if (startcode == PADDING_STREAM) {
00273         avio_skip(s->pb, avio_rb16(s->pb));
00274         goto redo;
00275     }
00276     if (startcode == PRIVATE_STREAM_2) {
00277         len = avio_rb16(s->pb);
00278         if (!m->sofdec) {
00279             while (len-- >= 6) {
00280                 if (avio_r8(s->pb) == 'S') {
00281                     uint8_t buf[5];
00282                     avio_read(s->pb, buf, sizeof(buf));
00283                     m->sofdec = !memcmp(buf, "ofdec", 5);
00284                     len -= sizeof(buf);
00285                     break;
00286                 }
00287             }
00288             m->sofdec -= !m->sofdec;
00289         }
00290         avio_skip(s->pb, len);
00291         goto redo;
00292     }
00293     if (startcode == PROGRAM_STREAM_MAP) {
00294         mpegps_psm_parse(m, s->pb);
00295         goto redo;
00296     }
00297 
00298     /* find matching stream */
00299     if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
00300           (startcode >= 0x1e0 && startcode <= 0x1ef) ||
00301           (startcode == 0x1bd) || (startcode == 0x1fd)))
00302         goto redo;
00303     if (ppos) {
00304         *ppos = avio_tell(s->pb) - 4;
00305     }
00306     len = avio_rb16(s->pb);
00307     pts =
00308     dts = AV_NOPTS_VALUE;
00309     /* stuffing */
00310     for(;;) {
00311         if (len < 1)
00312             goto error_redo;
00313         c = avio_r8(s->pb);
00314         len--;
00315         /* XXX: for mpeg1, should test only bit 7 */
00316         if (c != 0xff)
00317             break;
00318     }
00319     if ((c & 0xc0) == 0x40) {
00320         /* buffer scale & size */
00321         avio_r8(s->pb);
00322         c = avio_r8(s->pb);
00323         len -= 2;
00324     }
00325     if ((c & 0xe0) == 0x20) {
00326         dts = pts = get_pts(s->pb, c);
00327         len -= 4;
00328         if (c & 0x10){
00329             dts = get_pts(s->pb, -1);
00330             len -= 5;
00331         }
00332     } else if ((c & 0xc0) == 0x80) {
00333         /* mpeg 2 PES */
00334 #if 0 /* some streams have this field set for no apparent reason */
00335         if ((c & 0x30) != 0) {
00336             /* Encrypted multiplex not handled */
00337             goto redo;
00338         }
00339 #endif
00340         flags = avio_r8(s->pb);
00341         header_len = avio_r8(s->pb);
00342         len -= 2;
00343         if (header_len > len)
00344             goto error_redo;
00345         len -= header_len;
00346         if (flags & 0x80) {
00347             dts = pts = get_pts(s->pb, -1);
00348             header_len -= 5;
00349             if (flags & 0x40) {
00350                 dts = get_pts(s->pb, -1);
00351                 header_len -= 5;
00352             }
00353         }
00354         if (flags & 0x3f && header_len == 0){
00355             flags &= 0xC0;
00356             av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");
00357         }
00358         if (flags & 0x01) { /* PES extension */
00359             pes_ext = avio_r8(s->pb);
00360             header_len--;
00361             /* Skip PES private data, program packet sequence counter and P-STD buffer */
00362             skip = (pes_ext >> 4) & 0xb;
00363             skip += skip & 0x9;
00364             if (pes_ext & 0x40 || skip > header_len){
00365                 av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);
00366                 pes_ext=skip=0;
00367             }
00368             avio_skip(s->pb, skip);
00369             header_len -= skip;
00370 
00371             if (pes_ext & 0x01) { /* PES extension 2 */
00372                 ext2_len = avio_r8(s->pb);
00373                 header_len--;
00374                 if ((ext2_len & 0x7f) > 0) {
00375                     id_ext = avio_r8(s->pb);
00376                     if ((id_ext & 0x80) == 0)
00377                         startcode = ((startcode & 0xff) << 8) | id_ext;
00378                     header_len--;
00379                 }
00380             }
00381         }
00382         if(header_len < 0)
00383             goto error_redo;
00384         avio_skip(s->pb, header_len);
00385     }
00386     else if( c!= 0xf )
00387         goto redo;
00388 
00389     if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
00390         startcode = avio_r8(s->pb);
00391         len--;
00392         if (startcode >= 0x80 && startcode <= 0xcf) {
00393             /* audio: skip header */
00394             avio_r8(s->pb);
00395             avio_r8(s->pb);
00396             avio_r8(s->pb);
00397             len -= 3;
00398             if (startcode >= 0xb0 && startcode <= 0xbf) {
00399                 /* MLP/TrueHD audio has a 4-byte header */
00400                 avio_r8(s->pb);
00401                 len--;
00402             }
00403         }
00404     }
00405     if(len<0)
00406         goto error_redo;
00407     if(dts != AV_NOPTS_VALUE && ppos){
00408         int i;
00409         for(i=0; i<s->nb_streams; i++){
00410             if(startcode == s->streams[i]->id &&
00411                s->pb->seekable /* index useless on streams anyway */) {
00412                 ff_reduce_index(s, i);
00413                 av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
00414             }
00415         }
00416     }
00417 
00418     *pstart_code = startcode;
00419     *ppts = pts;
00420     *pdts = dts;
00421     return len;
00422 }
00423 
00424 static int mpegps_read_packet(AVFormatContext *s,
00425                               AVPacket *pkt)
00426 {
00427     MpegDemuxContext *m = s->priv_data;
00428     AVStream *st;
00429     int len, startcode, i, es_type, ret;
00430     int request_probe= 0;
00431     enum CodecID codec_id = CODEC_ID_NONE;
00432     enum AVMediaType type;
00433     int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
00434     uint8_t av_uninit(dvdaudio_substream_type);
00435 
00436  redo:
00437     len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
00438     if (len < 0)
00439         return len;
00440 
00441     if(startcode == 0x1bd) {
00442         dvdaudio_substream_type = avio_r8(s->pb);
00443         avio_skip(s->pb, 3);
00444         len -= 4;
00445     }
00446 
00447     /* now find stream */
00448     for(i=0;i<s->nb_streams;i++) {
00449         st = s->streams[i];
00450         if (st->id == startcode)
00451             goto found;
00452     }
00453 
00454     es_type = m->psm_es_type[startcode & 0xff];
00455     if(es_type > 0 && es_type != STREAM_TYPE_PRIVATE_DATA){
00456         if(es_type == STREAM_TYPE_VIDEO_MPEG1){
00457             codec_id = CODEC_ID_MPEG2VIDEO;
00458             type = AVMEDIA_TYPE_VIDEO;
00459         } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
00460             codec_id = CODEC_ID_MPEG2VIDEO;
00461             type = AVMEDIA_TYPE_VIDEO;
00462         } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
00463                   es_type == STREAM_TYPE_AUDIO_MPEG2){
00464             codec_id = CODEC_ID_MP3;
00465             type = AVMEDIA_TYPE_AUDIO;
00466         } else if(es_type == STREAM_TYPE_AUDIO_AAC){
00467             codec_id = CODEC_ID_AAC;
00468             type = AVMEDIA_TYPE_AUDIO;
00469         } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
00470             codec_id = CODEC_ID_MPEG4;
00471             type = AVMEDIA_TYPE_VIDEO;
00472         } else if(es_type == STREAM_TYPE_VIDEO_H264){
00473             codec_id = CODEC_ID_H264;
00474             type = AVMEDIA_TYPE_VIDEO;
00475         } else if(es_type == STREAM_TYPE_AUDIO_AC3){
00476             codec_id = CODEC_ID_AC3;
00477             type = AVMEDIA_TYPE_AUDIO;
00478         } else {
00479             goto skip;
00480         }
00481     } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
00482         static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
00483         unsigned char buf[8];
00484         avio_read(s->pb, buf, 8);
00485         avio_seek(s->pb, -8, SEEK_CUR);
00486         if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
00487             codec_id = CODEC_ID_CAVS;
00488         else
00489             request_probe= 1;
00490         type = AVMEDIA_TYPE_VIDEO;
00491     } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
00492         type = AVMEDIA_TYPE_AUDIO;
00493         codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
00494     } else if (startcode >= 0x80 && startcode <= 0x87) {
00495         type = AVMEDIA_TYPE_AUDIO;
00496         codec_id = CODEC_ID_AC3;
00497     } else if (  ( startcode >= 0x88 && startcode <= 0x8f)
00498                ||( startcode >= 0x98 && startcode <= 0x9f)) {
00499         /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
00500         type = AVMEDIA_TYPE_AUDIO;
00501         codec_id = CODEC_ID_DTS;
00502     } else if (startcode >= 0xa0 && startcode <= 0xaf) {
00503         type = AVMEDIA_TYPE_AUDIO;
00504         /* 16 bit form will be handled as CODEC_ID_PCM_S16BE */
00505         codec_id = CODEC_ID_PCM_DVD;
00506     } else if (startcode >= 0xb0 && startcode <= 0xbf) {
00507         type = AVMEDIA_TYPE_AUDIO;
00508         codec_id = CODEC_ID_TRUEHD;
00509     } else if (startcode >= 0xc0 && startcode <= 0xcf) {
00510         /* Used for both AC-3 and E-AC-3 in EVOB files */
00511         type = AVMEDIA_TYPE_AUDIO;
00512         codec_id = CODEC_ID_AC3;
00513     } else if (startcode >= 0x20 && startcode <= 0x3f) {
00514         type = AVMEDIA_TYPE_SUBTITLE;
00515         codec_id = CODEC_ID_DVD_SUBTITLE;
00516     } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
00517         type = AVMEDIA_TYPE_VIDEO;
00518         codec_id = CODEC_ID_VC1;
00519     } else if (startcode == 0x1bd) {
00520         // check dvd audio substream type
00521         type = AVMEDIA_TYPE_AUDIO;
00522         switch(dvdaudio_substream_type & 0xe0) {
00523         case 0xa0:  codec_id = CODEC_ID_PCM_DVD;
00524                     break;
00525         case 0x80:  if((dvdaudio_substream_type & 0xf8) == 0x88)
00526                          codec_id = CODEC_ID_DTS;
00527                     else codec_id = CODEC_ID_AC3;
00528                     break;
00529         default:    av_log(s, AV_LOG_ERROR, "Unknown 0x1bd sub-stream\n");
00530                     goto skip;
00531         }
00532     } else {
00533     skip:
00534         /* skip packet */
00535         avio_skip(s->pb, len);
00536         goto redo;
00537     }
00538     /* no stream found: add a new stream */
00539     st = avformat_new_stream(s, NULL);
00540     if (!st)
00541         goto skip;
00542     st->id = startcode;
00543     st->codec->codec_type = type;
00544     st->codec->codec_id = codec_id;
00545     st->request_probe     = request_probe;
00546     if (codec_id != CODEC_ID_PCM_S16BE)
00547         st->need_parsing = AVSTREAM_PARSE_FULL;
00548  found:
00549     if(st->discard >= AVDISCARD_ALL)
00550         goto skip;
00551     if ((startcode >= 0xa0 && startcode <= 0xaf) ||
00552         (startcode == 0x1bd && ((dvdaudio_substream_type & 0xe0) == 0xa0))) {
00553         int b1, freq;
00554 
00555         /* for LPCM, we just skip the header and consider it is raw
00556            audio data */
00557         if (len <= 3)
00558             goto skip;
00559         avio_r8(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
00560         b1 = avio_r8(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
00561         avio_r8(s->pb); /* dynamic range control (0x80 = off) */
00562         len -= 3;
00563         freq = (b1 >> 4) & 3;
00564         st->codec->sample_rate = lpcm_freq_tab[freq];
00565         st->codec->channels = 1 + (b1 & 7);
00566         st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;
00567         st->codec->bit_rate = st->codec->channels *
00568                               st->codec->sample_rate *
00569                               st->codec->bits_per_coded_sample;
00570         if (st->codec->bits_per_coded_sample == 16)
00571             st->codec->codec_id = CODEC_ID_PCM_S16BE;
00572         else if (st->codec->bits_per_coded_sample == 28)
00573             return AVERROR(EINVAL);
00574     }
00575     ret = av_get_packet(s->pb, pkt, len);
00576     pkt->pts = pts;
00577     pkt->dts = dts;
00578     pkt->pos = dummy_pos;
00579     pkt->stream_index = st->index;
00580     av_dlog(s, "%d: pts=%0.3f dts=%0.3f size=%d\n",
00581             pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0,
00582             pkt->size);
00583 
00584     return (ret < 0) ? ret : 0;
00585 }
00586 
00587 static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
00588                                int64_t *ppos, int64_t pos_limit)
00589 {
00590     int len, startcode;
00591     int64_t pos, pts, dts;
00592 
00593     pos = *ppos;
00594     if (avio_seek(s->pb, pos, SEEK_SET) < 0)
00595         return AV_NOPTS_VALUE;
00596 
00597     for(;;) {
00598         len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
00599         if (len < 0) {
00600             av_dlog(s, "none (ret=%d)\n", len);
00601             return AV_NOPTS_VALUE;
00602         }
00603         if (startcode == s->streams[stream_index]->id &&
00604             dts != AV_NOPTS_VALUE) {
00605             break;
00606         }
00607         avio_skip(s->pb, len);
00608     }
00609     av_dlog(s, "pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n",
00610             pos, dts, dts / 90000.0);
00611     *ppos = pos;
00612     return dts;
00613 }
00614 
00615 AVInputFormat ff_mpegps_demuxer = {
00616     .name           = "mpeg",
00617     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-PS format"),
00618     .priv_data_size = sizeof(MpegDemuxContext),
00619     .read_probe     = mpegps_probe,
00620     .read_header    = mpegps_read_header,
00621     .read_packet    = mpegps_read_packet,
00622     .read_timestamp = mpegps_read_dts,
00623     .flags          = AVFMT_SHOW_IDS | AVFMT_TS_DISCONT,
00624 };