Libav
gxf.c
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1 /*
2  * GXF demuxer.
3  * Copyright (c) 2006 Reimar Doeffinger
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 
23 #include "libavutil/common.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "gxf.h"
27 #include "libavcodec/mpeg12data.h"
28 
30  int64_t first_field;
31  int64_t last_field;
34 };
35 
43 static int parse_packet_header(AVIOContext *pb, GXFPktType *type, int *length) {
44  if (avio_rb32(pb))
45  return 0;
46  if (avio_r8(pb) != 1)
47  return 0;
48  *type = avio_r8(pb);
49  *length = avio_rb32(pb);
50  if ((*length >> 24) || *length < 16)
51  return 0;
52  *length -= 16;
53  if (avio_rb32(pb))
54  return 0;
55  if (avio_r8(pb) != 0xe1)
56  return 0;
57  if (avio_r8(pb) != 0xe2)
58  return 0;
59  return 1;
60 }
61 
65 static int gxf_probe(AVProbeData *p) {
66  static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
67  static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
68  if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
69  !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
70  return AVPROBE_SCORE_MAX;
71  return 0;
72 }
73 
80 static int get_sindex(AVFormatContext *s, int id, int format) {
81  int i;
82  AVStream *st = NULL;
83  i = ff_find_stream_index(s, id);
84  if (i >= 0)
85  return i;
86  st = avformat_new_stream(s, NULL);
87  if (!st)
88  return AVERROR(ENOMEM);
89  st->id = id;
90  switch (format) {
91  case 3:
92  case 4:
95  break;
96  case 13:
97  case 15:
100  break;
101  case 14:
102  case 16:
105  break;
106  case 11:
107  case 12:
108  case 20:
111  st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
112  break;
113  case 22:
114  case 23:
117  st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
118  break;
119  case 9:
122  st->codec->channels = 1;
124  st->codec->sample_rate = 48000;
125  st->codec->bit_rate = 3 * 1 * 48000 * 8;
126  st->codec->block_align = 3 * 1;
127  st->codec->bits_per_coded_sample = 24;
128  break;
129  case 10:
132  st->codec->channels = 1;
134  st->codec->sample_rate = 48000;
135  st->codec->bit_rate = 2 * 1 * 48000 * 8;
136  st->codec->block_align = 2 * 1;
137  st->codec->bits_per_coded_sample = 16;
138  break;
139  case 17:
142  st->codec->channels = 2;
144  st->codec->sample_rate = 48000;
145  break;
146  // timecode tracks:
147  case 7:
148  case 8:
149  case 24:
152  break;
153  default:
156  break;
157  }
158  return s->nb_streams - 1;
159 }
160 
166 static void gxf_material_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
169  while (*len >= 2) {
170  GXFMatTag tag = avio_r8(pb);
171  int tlen = avio_r8(pb);
172  *len -= 2;
173  if (tlen > *len)
174  return;
175  *len -= tlen;
176  if (tlen == 4) {
177  uint32_t value = avio_rb32(pb);
178  if (tag == MAT_FIRST_FIELD)
179  si->first_field = value;
180  else if (tag == MAT_LAST_FIELD)
181  si->last_field = value;
182  } else
183  avio_skip(pb, tlen);
184  }
185 }
186 
187 static const AVRational frame_rate_tab[] = {
188  { 60, 1},
189  {60000, 1001},
190  { 50, 1},
191  { 30, 1},
192  {30000, 1001},
193  { 25, 1},
194  { 24, 1},
195  {24000, 1001},
196  { 0, 0},
197 };
198 
205  if (fps < 1 || fps > 9) fps = 9;
206  return frame_rate_tab[fps - 1];
207 }
208 
214 static AVRational fps_umf2avr(uint32_t flags) {
215  static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},
216  {25, 1}, {30000, 1001}};
217  int idx = av_log2((flags & 0x7c0) >> 6);
218  return map[idx];
219 }
220 
226 static void gxf_track_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
227  si->frames_per_second = (AVRational){0, 0};
228  si->fields_per_frame = 0;
229  while (*len >= 2) {
230  GXFTrackTag tag = avio_r8(pb);
231  int tlen = avio_r8(pb);
232  *len -= 2;
233  if (tlen > *len)
234  return;
235  *len -= tlen;
236  if (tlen == 4) {
237  uint32_t value = avio_rb32(pb);
238  if (tag == TRACK_FPS)
239  si->frames_per_second = fps_tag2avr(value);
240  else if (tag == TRACK_FPF && (value == 1 || value == 2))
241  si->fields_per_frame = value;
242  } else
243  avio_skip(pb, tlen);
244  }
245 }
246 
250 static void gxf_read_index(AVFormatContext *s, int pkt_len) {
251  AVIOContext *pb = s->pb;
252  AVStream *st = s->streams[0];
253  uint32_t fields_per_map = avio_rl32(pb);
254  uint32_t map_cnt = avio_rl32(pb);
255  int i;
256  pkt_len -= 8;
257  if (s->flags & AVFMT_FLAG_IGNIDX) {
258  avio_skip(pb, pkt_len);
259  return;
260  }
261  if (map_cnt > 1000) {
262  av_log(s, AV_LOG_ERROR, "too many index entries %u (%x)\n", map_cnt, map_cnt);
263  map_cnt = 1000;
264  }
265  if (pkt_len < 4 * map_cnt) {
266  av_log(s, AV_LOG_ERROR, "invalid index length\n");
267  avio_skip(pb, pkt_len);
268  return;
269  }
270  pkt_len -= 4 * map_cnt;
271  av_add_index_entry(st, 0, 0, 0, 0, 0);
272  for (i = 0; i < map_cnt; i++)
273  av_add_index_entry(st, (uint64_t)avio_rl32(pb) * 1024,
274  i * (uint64_t)fields_per_map + 1, 0, 0, 0);
275  avio_skip(pb, pkt_len);
276 }
277 
278 static int gxf_header(AVFormatContext *s) {
279  AVIOContext *pb = s->pb;
280  GXFPktType pkt_type;
281  int map_len;
282  int len;
283  AVRational main_timebase = {0, 0};
284  struct gxf_stream_info *si = s->priv_data;
285  int i;
286  if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
287  av_log(s, AV_LOG_ERROR, "map packet not found\n");
288  return 0;
289  }
290  map_len -= 2;
291  if (avio_r8(pb) != 0x0e0 || avio_r8(pb) != 0xff) {
292  av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");
293  return 0;
294  }
295  map_len -= 2;
296  len = avio_rb16(pb); // length of material data section
297  if (len > map_len) {
298  av_log(s, AV_LOG_ERROR, "material data longer than map data\n");
299  return 0;
300  }
301  map_len -= len;
302  gxf_material_tags(pb, &len, si);
303  avio_skip(pb, len);
304  map_len -= 2;
305  len = avio_rb16(pb); // length of track description
306  if (len > map_len) {
307  av_log(s, AV_LOG_ERROR, "track description longer than map data\n");
308  return 0;
309  }
310  map_len -= len;
311  while (len > 0) {
312  int track_type, track_id, track_len;
313  AVStream *st;
314  int idx;
315  len -= 4;
316  track_type = avio_r8(pb);
317  track_id = avio_r8(pb);
318  track_len = avio_rb16(pb);
319  len -= track_len;
320  gxf_track_tags(pb, &track_len, si);
321  avio_skip(pb, track_len);
322  if (!(track_type & 0x80)) {
323  av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);
324  continue;
325  }
326  track_type &= 0x7f;
327  if ((track_id & 0xc0) != 0xc0) {
328  av_log(s, AV_LOG_ERROR, "invalid track id %x\n", track_id);
329  continue;
330  }
331  track_id &= 0x3f;
332  idx = get_sindex(s, track_id, track_type);
333  if (idx < 0) continue;
334  st = s->streams[idx];
335  if (!main_timebase.num || !main_timebase.den) {
336  main_timebase.num = si->frames_per_second.den;
337  main_timebase.den = si->frames_per_second.num * 2;
338  }
339  st->start_time = si->first_field;
341  st->duration = si->last_field - si->first_field;
342  }
343  if (len < 0)
344  av_log(s, AV_LOG_ERROR, "invalid track description length specified\n");
345  if (map_len)
346  avio_skip(pb, map_len);
347  if (!parse_packet_header(pb, &pkt_type, &len)) {
348  av_log(s, AV_LOG_ERROR, "sync lost in header\n");
349  return -1;
350  }
351  if (pkt_type == PKT_FLT) {
352  gxf_read_index(s, len);
353  if (!parse_packet_header(pb, &pkt_type, &len)) {
354  av_log(s, AV_LOG_ERROR, "sync lost in header\n");
355  return -1;
356  }
357  }
358  if (pkt_type == PKT_UMF) {
359  if (len >= 0x39) {
360  AVRational fps;
361  len -= 0x39;
362  avio_skip(pb, 5); // preamble
363  avio_skip(pb, 0x30); // payload description
364  fps = fps_umf2avr(avio_rl32(pb));
365  if (!main_timebase.num || !main_timebase.den) {
366  // this may not always be correct, but simply the best we can get
367  main_timebase.num = fps.den;
368  main_timebase.den = fps.num * 2;
369  }
370  } else
371  av_log(s, AV_LOG_INFO, "UMF packet too short\n");
372  } else
373  av_log(s, AV_LOG_INFO, "UMF packet missing\n");
374  avio_skip(pb, len);
375  // set a fallback value, 60000/1001 is specified for audio-only files
376  // so use that regardless of why we do not know the video frame rate.
377  if (!main_timebase.num || !main_timebase.den)
378  main_timebase = (AVRational){1001, 60000};
379  for (i = 0; i < s->nb_streams; i++) {
380  AVStream *st = s->streams[i];
381  avpriv_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
382  }
383  return 0;
384 }
385 
386 #define READ_ONE() \
387  { \
388  if (!max_interval-- || pb->eof_reached) \
389  goto out; \
390  tmp = tmp << 8 | avio_r8(pb); \
391  }
392 
400 static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
401  uint32_t tmp;
402  uint64_t last_pos;
403  uint64_t last_found_pos = 0;
404  int cur_track;
405  int64_t cur_timestamp = AV_NOPTS_VALUE;
406  int len;
407  AVIOContext *pb = s->pb;
408  GXFPktType type;
409  tmp = avio_rb32(pb);
410 start:
411  while (tmp)
412  READ_ONE();
413  READ_ONE();
414  if (tmp != 1)
415  goto start;
416  last_pos = avio_tell(pb);
417  if (avio_seek(pb, -5, SEEK_CUR) < 0)
418  goto out;
419  if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
420  if (avio_seek(pb, last_pos, SEEK_SET) < 0)
421  goto out;
422  goto start;
423  }
424  avio_r8(pb);
425  cur_track = avio_r8(pb);
426  cur_timestamp = avio_rb32(pb);
427  last_found_pos = avio_tell(pb) - 16 - 6;
428  if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
429  if (avio_seek(pb, last_pos, SEEK_SET) >= 0)
430  goto start;
431  }
432 out:
433  if (last_found_pos)
434  avio_seek(pb, last_found_pos, SEEK_SET);
435  return cur_timestamp;
436 }
437 
438 static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
439  AVIOContext *pb = s->pb;
440  GXFPktType pkt_type;
441  int pkt_len;
442  struct gxf_stream_info *si = s->priv_data;
443 
444  while (!pb->eof_reached) {
445  AVStream *st;
446  int track_type, track_id, ret;
447  int field_nr, field_info, skip = 0;
448  int stream_index;
449  if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
450  if (!pb->eof_reached)
451  av_log(s, AV_LOG_ERROR, "sync lost\n");
452  return -1;
453  }
454  if (pkt_type == PKT_FLT) {
455  gxf_read_index(s, pkt_len);
456  continue;
457  }
458  if (pkt_type != PKT_MEDIA) {
459  avio_skip(pb, pkt_len);
460  continue;
461  }
462  if (pkt_len < 16) {
463  av_log(s, AV_LOG_ERROR, "invalid media packet length\n");
464  continue;
465  }
466  pkt_len -= 16;
467  track_type = avio_r8(pb);
468  track_id = avio_r8(pb);
469  stream_index = get_sindex(s, track_id, track_type);
470  if (stream_index < 0)
471  return stream_index;
472  st = s->streams[stream_index];
473  field_nr = avio_rb32(pb);
474  field_info = avio_rb32(pb);
475  avio_rb32(pb); // "timeline" field number
476  avio_r8(pb); // flags
477  avio_r8(pb); // reserved
478  if (st->codec->codec_id == AV_CODEC_ID_PCM_S24LE ||
480  int first = field_info >> 16;
481  int last = field_info & 0xffff; // last is exclusive
482  int bps = av_get_bits_per_sample(st->codec->codec_id)>>3;
483  if (first <= last && last*bps <= pkt_len) {
484  avio_skip(pb, first*bps);
485  skip = pkt_len - last*bps;
486  pkt_len = (last-first)*bps;
487  } else
488  av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");
489  }
490  ret = av_get_packet(pb, pkt, pkt_len);
491  if (skip)
492  avio_skip(pb, skip);
493  pkt->stream_index = stream_index;
494  pkt->dts = field_nr;
495 
496  //set duration manually for DV or else lavf misdetects the frame rate
497  if (st->codec->codec_id == AV_CODEC_ID_DVVIDEO)
498  pkt->duration = si->fields_per_frame;
499 
500  return ret;
501  }
502  return AVERROR(EIO);
503 }
504 
505 static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
506  int res = 0;
507  uint64_t pos;
508  uint64_t maxlen = 100 * 1024 * 1024;
509  AVStream *st = s->streams[0];
510  int64_t start_time = s->streams[stream_index]->start_time;
511  int64_t found;
512  int idx;
513  if (timestamp < start_time) timestamp = start_time;
514  idx = av_index_search_timestamp(st, timestamp - start_time,
516  if (idx < 0)
517  return -1;
518  pos = st->index_entries[idx].pos;
519  if (idx < st->nb_index_entries - 2)
520  maxlen = st->index_entries[idx + 2].pos - pos;
521  maxlen = FFMAX(maxlen, 200 * 1024);
522  res = avio_seek(s->pb, pos, SEEK_SET);
523  if (res < 0)
524  return res;
525  found = gxf_resync_media(s, maxlen, -1, timestamp);
526  if (FFABS(found - timestamp) > 4)
527  return -1;
528  return 0;
529 }
530 
531 static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
532  int64_t *pos, int64_t pos_limit) {
533  AVIOContext *pb = s->pb;
534  int64_t res;
535  if (avio_seek(pb, *pos, SEEK_SET) < 0)
536  return AV_NOPTS_VALUE;
537  res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
538  *pos = avio_tell(pb);
539  return res;
540 }
541 
543  .name = "gxf",
544  .long_name = NULL_IF_CONFIG_SMALL("GXF (General eXchange Format)"),
545  .priv_data_size = sizeof(struct gxf_stream_info),
546  .read_probe = gxf_probe,
547  .read_header = gxf_header,
548  .read_packet = gxf_packet,
549  .read_seek = gxf_seek,
550  .read_timestamp = gxf_read_timestamp,
551 };