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mpeg.c
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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 "internal.h"
24 #include "mpeg.h"
25 
26 #if CONFIG_VOBSUB_DEMUXER
27 # include "subtitles.h"
28 # include "libavutil/bprint.h"
29 #endif
30 
31 #undef NDEBUG
32 #include <assert.h>
33 #include "libavutil/avassert.h"
34 
35 /*********************************************/
36 /* demux code */
37 
38 #define MAX_SYNC_SIZE 100000
39 
40 static int check_pes(const uint8_t *p, const uint8_t *end){
41  int pes1;
42  int pes2= (p[3] & 0xC0) == 0x80
43  && (p[4] & 0xC0) != 0x40
44  &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));
45 
46  for(p+=3; p<end && *p == 0xFF; p++);
47  if((*p&0xC0) == 0x40) p+=2;
48  if((*p&0xF0) == 0x20){
49  pes1= p[0]&p[2]&p[4]&1;
50  }else if((*p&0xF0) == 0x30){
51  pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
52  }else
53  pes1 = *p == 0x0F;
54 
55  return pes1||pes2;
56 }
57 
58 static int check_pack_header(const uint8_t *buf) {
59  return (buf[1] & 0xC0) == 0x40 || (buf[1] & 0xF0) == 0x20;
60 }
61 
62 static int mpegps_probe(AVProbeData *p)
63 {
64  uint32_t code= -1;
65  int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
66  int i;
67  int score=0;
68 
69  for(i=0; i<p->buf_size; i++){
70  code = (code<<8) + p->buf[i];
71  if ((code & 0xffffff00) == 0x100) {
72  int len= p->buf[i+1] << 8 | p->buf[i+2];
73  int pes= check_pes(p->buf+i, p->buf+p->buf_size);
74  int pack = check_pack_header(p->buf+i);
75 
76  if(code == SYSTEM_HEADER_START_CODE) sys++;
77  else if(code == PACK_START_CODE && pack) pspack++;
78  else if((code & 0xf0) == VIDEO_ID && pes) vid++;
79  // skip pes payload to avoid start code emulation for private
80  // and audio streams
81  else if((code & 0xe0) == AUDIO_ID && pes) {audio++; i+=len;}
82  else if(code == PRIVATE_STREAM_1 && pes) {priv1++; i+=len;}
83  else if(code == 0x1fd && pes) vid++; //VC1
84 
85  else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
86  else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
87  else if(code == PRIVATE_STREAM_1 && !pes) invalid++;
88  }
89  }
90 
91  if(vid+audio > invalid+1) /* invalid VDR files nd short PES streams */
92  score = AVPROBE_SCORE_EXTENSION / 2;
93 
94  if(sys>invalid && sys*9 <= pspack*10)
95  return (audio > 12 || vid > 3 || pspack > 2) ? AVPROBE_SCORE_EXTENSION + 2 : AVPROBE_SCORE_EXTENSION / 2; // 1 more than .mpg
96  if(pspack > invalid && (priv1+vid+audio)*10 >= pspack*9)
97  return pspack > 2 ? AVPROBE_SCORE_EXTENSION + 2 : AVPROBE_SCORE_EXTENSION / 2; // 1 more than .mpg
98  if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */
99  return (audio > 12 || vid > 3 + 2*invalid) ? AVPROBE_SCORE_EXTENSION + 2 : AVPROBE_SCORE_EXTENSION / 2;
100 
101  //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
102  //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6
103  //Have\ Yourself\ a\ Merry\ Little\ Christmas.mp3 0 0 0 5 0 1 len:21618
104  return score;
105 }
106 
107 
108 typedef struct MpegDemuxContext {
110  unsigned char psm_es_type[256];
111  int sofdec;
112  int dvd;
114 #if CONFIG_VOBSUB_DEMUXER
115  AVFormatContext *sub_ctx;
117 #endif
119 
121 {
123  char buffer[7];
124  int64_t last_pos = avio_tell(s->pb);
125 
126  m->header_state = 0xff;
128 
129  avio_get_str(s->pb, 6, buffer, sizeof(buffer));
130  if (!memcmp("IMKH", buffer, 4)) {
131  m->imkh_cctv = 1;
132  } else if (!memcmp("Sofdec", buffer, 6)) {
133  m->sofdec = 1;
134  } else
135  avio_seek(s->pb, last_pos, SEEK_SET);
136 
137  /* no need to do more */
138  return 0;
139 }
140 
141 static int64_t get_pts(AVIOContext *pb, int c)
142 {
143  uint8_t buf[5];
144 
145  buf[0] = c<0 ? avio_r8(pb) : c;
146  avio_read(pb, buf+1, 4);
147 
148  return ff_parse_pes_pts(buf);
149 }
150 
151 static int find_next_start_code(AVIOContext *pb, int *size_ptr,
152  int32_t *header_state)
153 {
154  unsigned int state, v;
155  int val, n;
156 
157  state = *header_state;
158  n = *size_ptr;
159  while (n > 0) {
160  if (url_feof(pb))
161  break;
162  v = avio_r8(pb);
163  n--;
164  if (state == 0x000001) {
165  state = ((state << 8) | v) & 0xffffff;
166  val = state;
167  goto found;
168  }
169  state = ((state << 8) | v) & 0xffffff;
170  }
171  val = -1;
172  found:
173  *header_state = state;
174  *size_ptr = n;
175  return val;
176 }
177 
178 /**
179  * Extract stream types from a program stream map
180  * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
181  *
182  * @return number of bytes occupied by PSM in the bitstream
183  */
185 {
186  int psm_length, ps_info_length, es_map_length;
187 
188  psm_length = avio_rb16(pb);
189  avio_r8(pb);
190  avio_r8(pb);
191  ps_info_length = avio_rb16(pb);
192 
193  /* skip program_stream_info */
194  avio_skip(pb, ps_info_length);
195  es_map_length = avio_rb16(pb);
196 
197  /* at least one es available? */
198  while (es_map_length >= 4){
199  unsigned char type = avio_r8(pb);
200  unsigned char es_id = avio_r8(pb);
201  uint16_t es_info_length = avio_rb16(pb);
202  /* remember mapping from stream id to stream type */
203  m->psm_es_type[es_id] = type;
204  /* skip program_stream_info */
205  avio_skip(pb, es_info_length);
206  es_map_length -= 4 + es_info_length;
207  }
208  avio_rb32(pb); /* crc32 */
209  return 2 + psm_length;
210 }
211 
212 /* read the next PES header. Return its position in ppos
213  (if not NULL), and its start code, pts and dts.
214  */
216  int64_t *ppos, int *pstart_code,
217  int64_t *ppts, int64_t *pdts)
218 {
220  int len, size, startcode, c, flags, header_len;
221  int pes_ext, ext2_len, id_ext, skip;
222  int64_t pts, dts;
223  int64_t last_sync= avio_tell(s->pb);
224 
225  error_redo:
226  avio_seek(s->pb, last_sync, SEEK_SET);
227  redo:
228  /* next start code (should be immediately after) */
229  m->header_state = 0xff;
230  size = MAX_SYNC_SIZE;
231  startcode = find_next_start_code(s->pb, &size, &m->header_state);
232  last_sync = avio_tell(s->pb);
233  if (startcode < 0){
234  if(url_feof(s->pb))
235  return AVERROR_EOF;
236  //FIXME we should remember header_state
237  return AVERROR(EAGAIN);
238  }
239 
240  if (startcode == PACK_START_CODE)
241  goto redo;
242  if (startcode == SYSTEM_HEADER_START_CODE)
243  goto redo;
244  if (startcode == PADDING_STREAM) {
245  avio_skip(s->pb, avio_rb16(s->pb));
246  goto redo;
247  }
248  if (startcode == PRIVATE_STREAM_2) {
249  if (!m->sofdec) {
250  /* Need to detect whether this from a DVD or a 'Sofdec' stream */
251  int len = avio_rb16(s->pb);
252  int bytesread = 0;
253  uint8_t *ps2buf = av_malloc(len);
254 
255  if (ps2buf) {
256  bytesread = avio_read(s->pb, ps2buf, len);
257 
258  if (bytesread != len) {
259  avio_skip(s->pb, len - bytesread);
260  } else {
261  uint8_t *p = 0;
262  if (len >= 6)
263  p = memchr(ps2buf, 'S', len - 5);
264 
265  if (p)
266  m->sofdec = !memcmp(p+1, "ofdec", 5);
267 
268  m->sofdec -= !m->sofdec;
269 
270  if (m->sofdec < 0) {
271  if (len == 980 && ps2buf[0] == 0) {
272  /* PCI structure? */
273  uint32_t startpts = AV_RB32(ps2buf + 0x0d);
274  uint32_t endpts = AV_RB32(ps2buf + 0x11);
275  uint8_t hours = ((ps2buf[0x19] >> 4) * 10) + (ps2buf[0x19] & 0x0f);
276  uint8_t mins = ((ps2buf[0x1a] >> 4) * 10) + (ps2buf[0x1a] & 0x0f);
277  uint8_t secs = ((ps2buf[0x1b] >> 4) * 10) + (ps2buf[0x1b] & 0x0f);
278 
279  m->dvd = (hours <= 23 &&
280  mins <= 59 &&
281  secs <= 59 &&
282  (ps2buf[0x19] & 0x0f) < 10 &&
283  (ps2buf[0x1a] & 0x0f) < 10 &&
284  (ps2buf[0x1b] & 0x0f) < 10 &&
285  endpts >= startpts);
286  } else if (len == 1018 && ps2buf[0] == 1) {
287  /* DSI structure? */
288  uint8_t hours = ((ps2buf[0x1d] >> 4) * 10) + (ps2buf[0x1d] & 0x0f);
289  uint8_t mins = ((ps2buf[0x1e] >> 4) * 10) + (ps2buf[0x1e] & 0x0f);
290  uint8_t secs = ((ps2buf[0x1f] >> 4) * 10) + (ps2buf[0x1f] & 0x0f);
291 
292  m->dvd = (hours <= 23 &&
293  mins <= 59 &&
294  secs <= 59 &&
295  (ps2buf[0x1d] & 0x0f) < 10 &&
296  (ps2buf[0x1e] & 0x0f) < 10 &&
297  (ps2buf[0x1f] & 0x0f) < 10);
298  }
299  }
300  }
301 
302  av_free(ps2buf);
303 
304  /* If this isn't a DVD packet or no memory
305  * could be allocated, just ignore it.
306  * If we did, move back to the start of the
307  * packet (plus 'length' field) */
308  if (!m->dvd || avio_skip(s->pb, -(len + 2)) < 0) {
309  /* Skip back failed.
310  * This packet will be lost but that can't be helped
311  * if we can't skip back
312  */
313  goto redo;
314  }
315  } else {
316  /* No memory */
317  avio_skip(s->pb, len);
318  goto redo;
319  }
320  } else if (!m->dvd) {
321  int len = avio_rb16(s->pb);
322  avio_skip(s->pb, len);
323  goto redo;
324  }
325  }
326  if (startcode == PROGRAM_STREAM_MAP) {
327  mpegps_psm_parse(m, s->pb);
328  goto redo;
329  }
330 
331  /* find matching stream */
332  if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
333  (startcode >= 0x1e0 && startcode <= 0x1ef) ||
334  (startcode == 0x1bd) ||
335  (startcode == PRIVATE_STREAM_2) ||
336  (startcode == 0x1fd)))
337  goto redo;
338  if (ppos) {
339  *ppos = avio_tell(s->pb) - 4;
340  }
341  len = avio_rb16(s->pb);
342  pts =
343  dts = AV_NOPTS_VALUE;
344  if (startcode != PRIVATE_STREAM_2)
345  {
346  /* stuffing */
347  for(;;) {
348  if (len < 1)
349  goto error_redo;
350  c = avio_r8(s->pb);
351  len--;
352  /* XXX: for mpeg1, should test only bit 7 */
353  if (c != 0xff)
354  break;
355  }
356  if ((c & 0xc0) == 0x40) {
357  /* buffer scale & size */
358  avio_r8(s->pb);
359  c = avio_r8(s->pb);
360  len -= 2;
361  }
362  if ((c & 0xe0) == 0x20) {
363  dts = pts = get_pts(s->pb, c);
364  len -= 4;
365  if (c & 0x10){
366  dts = get_pts(s->pb, -1);
367  len -= 5;
368  }
369  } else if ((c & 0xc0) == 0x80) {
370  /* mpeg 2 PES */
371  flags = avio_r8(s->pb);
372  header_len = avio_r8(s->pb);
373  len -= 2;
374  if (header_len > len)
375  goto error_redo;
376  len -= header_len;
377  if (flags & 0x80) {
378  dts = pts = get_pts(s->pb, -1);
379  header_len -= 5;
380  if (flags & 0x40) {
381  dts = get_pts(s->pb, -1);
382  header_len -= 5;
383  }
384  }
385  if (flags & 0x3f && header_len == 0){
386  flags &= 0xC0;
387  av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");
388  }
389  if (flags & 0x01) { /* PES extension */
390  pes_ext = avio_r8(s->pb);
391  header_len--;
392  /* Skip PES private data, program packet sequence counter and P-STD buffer */
393  skip = (pes_ext >> 4) & 0xb;
394  skip += skip & 0x9;
395  if (pes_ext & 0x40 || skip > header_len){
396  av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);
397  pes_ext=skip=0;
398  }
399  avio_skip(s->pb, skip);
400  header_len -= skip;
401 
402  if (pes_ext & 0x01) { /* PES extension 2 */
403  ext2_len = avio_r8(s->pb);
404  header_len--;
405  if ((ext2_len & 0x7f) > 0) {
406  id_ext = avio_r8(s->pb);
407  if ((id_ext & 0x80) == 0)
408  startcode = ((startcode & 0xff) << 8) | id_ext;
409  header_len--;
410  }
411  }
412  }
413  if(header_len < 0)
414  goto error_redo;
415  avio_skip(s->pb, header_len);
416  }
417  else if( c!= 0xf )
418  goto redo;
419  }
420 
421  if (startcode == PRIVATE_STREAM_1) {
422  startcode = avio_r8(s->pb);
423  len--;
424  }
425  if(len<0)
426  goto error_redo;
427  if(dts != AV_NOPTS_VALUE && ppos){
428  int i;
429  for(i=0; i<s->nb_streams; i++){
430  if(startcode == s->streams[i]->id &&
431  s->pb->seekable /* index useless on streams anyway */) {
432  ff_reduce_index(s, i);
433  av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
434  }
435  }
436  }
437 
438  *pstart_code = startcode;
439  *ppts = pts;
440  *pdts = dts;
441  return len;
442 }
443 
445  AVPacket *pkt)
446 {
448  AVStream *st;
449  int len, startcode, i, es_type, ret;
450  int lpcm_header_len = -1; //Init to supress warning
451  int request_probe= 0;
453  enum AVMediaType type;
454  int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
455 
456  redo:
457  len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
458  if (len < 0)
459  return len;
460 
461  if (startcode >= 0x80 && startcode <= 0xcf) {
462  if(len < 4)
463  goto skip;
464 
465  /* audio: skip header */
466  avio_r8(s->pb);
467  lpcm_header_len = avio_rb16(s->pb);
468  len -= 3;
469  if (startcode >= 0xb0 && startcode <= 0xbf) {
470  /* MLP/TrueHD audio has a 4-byte header */
471  avio_r8(s->pb);
472  len--;
473  }
474  }
475 
476  /* now find stream */
477  for(i=0;i<s->nb_streams;i++) {
478  st = s->streams[i];
479  if (st->id == startcode)
480  goto found;
481  }
482 
483  es_type = m->psm_es_type[startcode & 0xff];
484  if(es_type == STREAM_TYPE_VIDEO_MPEG1){
485  codec_id = AV_CODEC_ID_MPEG2VIDEO;
486  type = AVMEDIA_TYPE_VIDEO;
487  } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
488  codec_id = AV_CODEC_ID_MPEG2VIDEO;
489  type = AVMEDIA_TYPE_VIDEO;
490  } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
491  es_type == STREAM_TYPE_AUDIO_MPEG2){
492  codec_id = AV_CODEC_ID_MP3;
493  type = AVMEDIA_TYPE_AUDIO;
494  } else if(es_type == STREAM_TYPE_AUDIO_AAC){
495  codec_id = AV_CODEC_ID_AAC;
496  type = AVMEDIA_TYPE_AUDIO;
497  } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
498  codec_id = AV_CODEC_ID_MPEG4;
499  type = AVMEDIA_TYPE_VIDEO;
500  } else if(es_type == STREAM_TYPE_VIDEO_H264){
501  codec_id = AV_CODEC_ID_H264;
502  type = AVMEDIA_TYPE_VIDEO;
503  } else if(es_type == STREAM_TYPE_AUDIO_AC3){
504  codec_id = AV_CODEC_ID_AC3;
505  type = AVMEDIA_TYPE_AUDIO;
506  } else if(m->imkh_cctv && es_type == 0x91){
507  codec_id = AV_CODEC_ID_PCM_MULAW;
508  type = AVMEDIA_TYPE_AUDIO;
509  } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
510  static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
511  unsigned char buf[8];
512  avio_read(s->pb, buf, 8);
513  avio_seek(s->pb, -8, SEEK_CUR);
514  if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
515  codec_id = AV_CODEC_ID_CAVS;
516  else
517  request_probe= 1;
518  type = AVMEDIA_TYPE_VIDEO;
519  } else if (startcode == PRIVATE_STREAM_2) {
520  type = AVMEDIA_TYPE_DATA;
521  codec_id = AV_CODEC_ID_DVD_NAV;
522  } else if (startcode >= 0x1c0 && startcode <= 0x1df) {
523  type = AVMEDIA_TYPE_AUDIO;
524  codec_id = m->sofdec > 0 ? AV_CODEC_ID_ADPCM_ADX : AV_CODEC_ID_MP2;
525  } else if (startcode >= 0x80 && startcode <= 0x87) {
526  type = AVMEDIA_TYPE_AUDIO;
527  codec_id = AV_CODEC_ID_AC3;
528  } else if ( ( startcode >= 0x88 && startcode <= 0x8f)
529  ||( startcode >= 0x98 && startcode <= 0x9f)) {
530  /* 0x90 - 0x97 is reserved for SDDS in DVD specs */
531  type = AVMEDIA_TYPE_AUDIO;
532  codec_id = AV_CODEC_ID_DTS;
533  } else if (startcode >= 0xa0 && startcode <= 0xaf) {
534  type = AVMEDIA_TYPE_AUDIO;
535  if(lpcm_header_len == 6) {
536  codec_id = AV_CODEC_ID_MLP;
537  } else {
538  /* 16 bit form will be handled as AV_CODEC_ID_PCM_S16BE */
539  codec_id = AV_CODEC_ID_PCM_DVD;
540  }
541  } else if (startcode >= 0xb0 && startcode <= 0xbf) {
542  type = AVMEDIA_TYPE_AUDIO;
543  codec_id = AV_CODEC_ID_TRUEHD;
544  } else if (startcode >= 0xc0 && startcode <= 0xcf) {
545  /* Used for both AC-3 and E-AC-3 in EVOB files */
546  type = AVMEDIA_TYPE_AUDIO;
547  codec_id = AV_CODEC_ID_AC3;
548  } else if (startcode >= 0x20 && startcode <= 0x3f) {
549  type = AVMEDIA_TYPE_SUBTITLE;
550  codec_id = AV_CODEC_ID_DVD_SUBTITLE;
551  } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
552  type = AVMEDIA_TYPE_VIDEO;
553  codec_id = AV_CODEC_ID_VC1;
554  } else {
555  skip:
556  /* skip packet */
557  avio_skip(s->pb, len);
558  goto redo;
559  }
560  /* no stream found: add a new stream */
561  st = avformat_new_stream(s, NULL);
562  if (!st)
563  goto skip;
564  st->id = startcode;
565  st->codec->codec_type = type;
566  st->codec->codec_id = codec_id;
567  if (st->codec->codec_id == AV_CODEC_ID_PCM_MULAW) {
568  st->codec->channels = 1;
570  st->codec->sample_rate = 8000;
571  }
572  st->request_probe = request_probe;
573  if (codec_id != AV_CODEC_ID_PCM_S16BE)
575  found:
576  if(st->discard >= AVDISCARD_ALL)
577  goto skip;
578  if (startcode >= 0xa0 && startcode <= 0xaf) {
579  if (lpcm_header_len == 6 && st->codec->codec_id == AV_CODEC_ID_MLP) {
580  if (len < 6)
581  goto skip;
582  avio_skip(s->pb, 6);
583  len -=6;
584  } else {
585  int b1, freq;
586 
587  /* for LPCM, we just skip the header and consider it is raw
588  audio data */
589  if (len <= 3)
590  goto skip;
591  avio_r8(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
592  b1 = avio_r8(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
593  avio_r8(s->pb); /* dynamic range control (0x80 = off) */
594  len -= 3;
595  freq = (b1 >> 4) & 3;
596  st->codec->sample_rate = lpcm_freq_tab[freq];
597  st->codec->channels = 1 + (b1 & 7);
598  st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;
599  st->codec->bit_rate = st->codec->channels *
600  st->codec->sample_rate *
602  if (st->codec->bits_per_coded_sample == 16)
604  else if (st->codec->bits_per_coded_sample == 28)
605  return AVERROR(EINVAL);
606  }
607  }
608  ret = av_get_packet(s->pb, pkt, len);
609  pkt->pts = pts;
610  pkt->dts = dts;
611  pkt->pos = dummy_pos;
612  pkt->stream_index = st->index;
613  av_dlog(s, "%d: pts=%0.3f dts=%0.3f size=%d\n",
614  pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0,
615  pkt->size);
616 
617  return (ret < 0) ? ret : 0;
618 }
619 
620 static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
621  int64_t *ppos, int64_t pos_limit)
622 {
623  int len, startcode;
624  int64_t pos, pts, dts;
625 
626  pos = *ppos;
627  if (avio_seek(s->pb, pos, SEEK_SET) < 0)
628  return AV_NOPTS_VALUE;
629 
630  for(;;) {
631  len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
632  if (len < 0) {
633  av_dlog(s, "none (ret=%d)\n", len);
634  return AV_NOPTS_VALUE;
635  }
636  if (startcode == s->streams[stream_index]->id &&
637  dts != AV_NOPTS_VALUE) {
638  break;
639  }
640  avio_skip(s->pb, len);
641  }
642  av_dlog(s, "pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n",
643  pos, dts, dts / 90000.0);
644  *ppos = pos;
645  return dts;
646 }
647 
649  .name = "mpeg",
650  .long_name = NULL_IF_CONFIG_SMALL("MPEG-PS (MPEG-2 Program Stream)"),
651  .priv_data_size = sizeof(MpegDemuxContext),
655  .read_timestamp = mpegps_read_dts,
657 };
658 
659 #if CONFIG_VOBSUB_DEMUXER
660 
661 #define REF_STRING "# VobSub index file,"
662 
663 static int vobsub_probe(AVProbeData *p)
664 {
665  if (!strncmp(p->buf, REF_STRING, sizeof(REF_STRING) - 1))
666  return AVPROBE_SCORE_MAX;
667  return 0;
668 }
669 
670 static int vobsub_read_header(AVFormatContext *s)
671 {
672  int i, ret = 0, header_parsed = 0, langidx = 0;
673  MpegDemuxContext *vobsub = s->priv_data;
674  char *sub_name = NULL;
675  size_t fname_len;
676  char *ext, *header_str;
677  AVBPrint header;
678  int64_t delay = 0;
679  AVStream *st = NULL;
680 
681  sub_name = av_strdup(s->filename);
682  fname_len = strlen(sub_name);
683  ext = sub_name - 3 + fname_len;
684  if (fname_len < 4 || *(ext - 1) != '.') {
685  av_log(s, AV_LOG_ERROR, "The input index filename is too short "
686  "to guess the associated .SUB file\n");
687  ret = AVERROR_INVALIDDATA;
688  goto end;
689  }
690  memcpy(ext, !strncmp(ext, "IDX", 3) ? "SUB" : "sub", 3);
691  av_log(s, AV_LOG_VERBOSE, "IDX/SUB: %s -> %s\n", s->filename, sub_name);
692  ret = avformat_open_input(&vobsub->sub_ctx, sub_name, &ff_mpegps_demuxer, NULL);
693  if (ret < 0) {
694  av_log(s, AV_LOG_ERROR, "Unable to open %s as MPEG subtitles\n", sub_name);
695  goto end;
696  }
697 
699  while (!url_feof(s->pb)) {
700  char line[2048];
701  int len = ff_get_line(s->pb, line, sizeof(line));
702 
703  if (!len)
704  break;
705 
706  line[strcspn(line, "\r\n")] = 0;
707 
708  if (!strncmp(line, "id:", 3)) {
709  int n, stream_id = 0;
710  char id[64] = {0};
711 
712  n = sscanf(line, "id: %63[^,], index: %u", id, &stream_id);
713  if (n != 2) {
714  av_log(s, AV_LOG_WARNING, "Unable to parse index line '%s', "
715  "assuming 'id: und, index: 0'\n", line);
716  strcpy(id, "und");
717  stream_id = 0;
718  }
719 
720  st = avformat_new_stream(s, NULL);
721  if (!st) {
722  ret = AVERROR(ENOMEM);
723  goto end;
724  }
725  st->id = stream_id;
728  av_dict_set(&st->metadata, "language", id, 0);
729  av_log(s, AV_LOG_DEBUG, "IDX stream[%d] id=%s\n", stream_id, id);
730  header_parsed = 1;
731 
732  } else if (st && !strncmp(line, "timestamp:", 10)) {
733  AVPacket *sub;
734  int hh, mm, ss, ms;
735  int64_t pos, timestamp;
736  const char *p = line + 10;
737 
738  if (sscanf(p, "%02d:%02d:%02d:%03d, filepos: %"SCNx64,
739  &hh, &mm, &ss, &ms, &pos) != 5) {
740  av_log(s, AV_LOG_ERROR, "Unable to parse timestamp line '%s', "
741  "abort parsing\n", line);
742  break;
743  }
744  timestamp = (hh*3600LL + mm*60LL + ss) * 1000LL + ms + delay;
745  timestamp = av_rescale_q(timestamp, (AVRational){1,1000}, st->time_base);
746 
747  sub = ff_subtitles_queue_insert(&vobsub->q, "", 0, 0);
748  if (!sub) {
749  ret = AVERROR(ENOMEM);
750  goto end;
751  }
752  sub->pos = pos;
753  sub->pts = timestamp;
754  sub->stream_index = s->nb_streams - 1;
755 
756  } else if (st && !strncmp(line, "alt:", 4)) {
757  const char *p = line + 4;
758 
759  while (*p == ' ')
760  p++;
761  av_dict_set(&st->metadata, "title", p, 0);
762  av_log(s, AV_LOG_DEBUG, "IDX stream[%d] name=%s\n", st->id, p);
763  header_parsed = 1;
764 
765  } else if (!strncmp(line, "delay:", 6)) {
766  int sign = 1, hh = 0, mm = 0, ss = 0, ms = 0;
767  const char *p = line + 6;
768 
769  while (*p == ' ')
770  p++;
771  if (*p == '-' || *p == '+') {
772  sign = *p == '-' ? -1 : 1;
773  p++;
774  }
775  sscanf(p, "%d:%d:%d:%d", &hh, &mm, &ss, &ms);
776  delay = ((hh*3600LL + mm*60LL + ss) * 1000LL + ms) * sign;
777 
778  } else if (!strncmp(line, "langidx:", 8)) {
779  const char *p = line + 8;
780 
781  if (sscanf(p, "%d", &langidx) != 1)
782  av_log(s, AV_LOG_ERROR, "Invalid langidx specified\n");
783 
784  } else if (!header_parsed) {
785  if (line[0] && line[0] != '#')
786  av_bprintf(&header, "%s\n", line);
787  }
788  }
789 
790  if (langidx < s->nb_streams)
792 
793  ff_subtitles_queue_finalize(&vobsub->q);
794 
795  if (!av_bprint_is_complete(&header)) {
796  av_bprint_finalize(&header, NULL);
797  ret = AVERROR(ENOMEM);
798  goto end;
799  }
800  av_bprint_finalize(&header, &header_str);
801  for (i = 0; i < s->nb_streams; i++) {
802  AVStream *sub_st = s->streams[i];
803  sub_st->codec->extradata = av_strdup(header_str);
804  sub_st->codec->extradata_size = header.len;
805  }
806  av_free(header_str);
807 
808 end:
809  av_free(sub_name);
810  return ret;
811 }
812 
813 #define FAIL(r) do { ret = r; goto fail; } while (0)
814 
815 static int vobsub_read_packet(AVFormatContext *s, AVPacket *pkt)
816 {
817  MpegDemuxContext *vobsub = s->priv_data;
818  FFDemuxSubtitlesQueue *q = &vobsub->q;
819  AVIOContext *pb = vobsub->sub_ctx->pb;
820  int ret, psize, len16 = -1;
821  AVPacket idx_pkt;
822 
823  ret = ff_subtitles_queue_read_packet(q, &idx_pkt);
824  if (ret < 0)
825  return ret;
826 
827  /* compute maximum packet size using the next packet position. This is
828  * useful when the len in the header is non-sense */
829  if (q->current_sub_idx < q->nb_subs) {
830  psize = q->subs[q->current_sub_idx].pos - idx_pkt.pos;
831  } else {
832  int64_t fsize = avio_size(pb);
833  psize = fsize < 0 ? 0xffff : fsize - idx_pkt.pos;
834  }
835 
836  avio_seek(pb, idx_pkt.pos, SEEK_SET);
837 
838  av_init_packet(pkt);
839  pkt->size = 0;
840  pkt->data = NULL;
841 
842  do {
843  int n, to_read, startcode;
844  int64_t pts, dts;
845 
846  ret = mpegps_read_pes_header(vobsub->sub_ctx, NULL, &startcode, &pts, &dts);
847  if (ret < 0)
848  FAIL(ret);
849  to_read = ret & 0xffff;
850 
851  /* this prevents reads above the current packet */
852  if (pkt->size + to_read > psize)
853  break;
854 
855  /* if the len is computed, we check for overread */
856  if (len16 != -1 && pkt->size + to_read > len16)
857  break;
858 
859  /* the current chunk doesn't match the stream index (unlikely) */
860  if ((startcode & 0x1f) != idx_pkt.stream_index)
861  break;
862 
863  ret = av_grow_packet(pkt, to_read);
864  if (ret < 0)
865  FAIL(ret);
866 
867  n = avio_read(pb, pkt->data + (pkt->size - to_read), to_read);
868  if (n < to_read)
869  pkt->size -= to_read - n;
870 
871  /* first chunk contains the total len of the packet to raise */
872  if (len16 == -1 && n > 2)
873  len16 = AV_RB16(pkt->data);
874  } while (len16 != -1 && pkt->size != len16);
875 
876  pkt->pts = pkt->dts = idx_pkt.pts;
877  pkt->pos = idx_pkt.pos;
878  pkt->stream_index = idx_pkt.stream_index;
879 
880  av_free_packet(&idx_pkt);
881  return 0;
882 
883 fail:
884  av_free_packet(&idx_pkt);
885  return ret;
886 }
887 
888 static int vobsub_read_seek(AVFormatContext *s, int stream_index,
889  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
890 {
891  MpegDemuxContext *vobsub = s->priv_data;
892  return ff_subtitles_queue_seek(&vobsub->q, s, stream_index,
893  min_ts, ts, max_ts, flags);
894 }
895 
896 static int vobsub_read_close(AVFormatContext *s)
897 {
898  MpegDemuxContext *vobsub = s->priv_data;
899  ff_subtitles_queue_clean(&vobsub->q);
900  if (vobsub->sub_ctx)
901  avformat_close_input(&vobsub->sub_ctx);
902  return 0;
903 }
904 
905 AVInputFormat ff_vobsub_demuxer = {
906  .name = "vobsub",
907  .long_name = NULL_IF_CONFIG_SMALL("VobSub subtitle format"),
908  .priv_data_size = sizeof(MpegDemuxContext),
909  .read_probe = vobsub_probe,
910  .read_header = vobsub_read_header,
911  .read_packet = vobsub_read_packet,
912  .read_seek2 = vobsub_read_seek,
913  .read_close = vobsub_read_close,
914  .flags = AVFMT_SHOW_IDS,
915  .extensions = "idx",
916 };
917 #endif