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 
22 #include "libavutil/common.h"
23 #include "avformat.h"
24 #include "internal.h"
25 #include "gxf.h"
26 
28  int64_t first_field;
29  int64_t last_field;
32 };
33 
41 static int parse_packet_header(AVIOContext *pb, GXFPktType *type, int *length) {
42  if (avio_rb32(pb))
43  return 0;
44  if (avio_r8(pb) != 1)
45  return 0;
46  *type = avio_r8(pb);
47  *length = avio_rb32(pb);
48  if ((*length >> 24) || *length < 16)
49  return 0;
50  *length -= 16;
51  if (avio_rb32(pb))
52  return 0;
53  if (avio_r8(pb) != 0xe1)
54  return 0;
55  if (avio_r8(pb) != 0xe2)
56  return 0;
57  return 1;
58 }
59 
63 static int gxf_probe(AVProbeData *p) {
64  static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
65  static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
66  if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
67  !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
68  return AVPROBE_SCORE_MAX;
69  return 0;
70 }
71 
78 static int get_sindex(AVFormatContext *s, int id, int format) {
79  int i;
80  AVStream *st = NULL;
81  i = ff_find_stream_index(s, id);
82  if (i >= 0)
83  return i;
84  st = avformat_new_stream(s, NULL);
85  if (!st)
86  return AVERROR(ENOMEM);
87  st->id = id;
88  switch (format) {
89  case 3:
90  case 4:
93  break;
94  case 13:
95  case 15:
98  break;
99  case 14:
100  case 16:
103  break;
104  case 11:
105  case 12:
106  case 20:
109  st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
110  break;
111  case 22:
112  case 23:
115  st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
116  break;
117  case 9:
120  st->codec->channels = 1;
121  st->codec->sample_rate = 48000;
122  st->codec->bit_rate = 3 * 1 * 48000 * 8;
123  st->codec->block_align = 3 * 1;
124  st->codec->bits_per_coded_sample = 24;
125  break;
126  case 10:
129  st->codec->channels = 1;
130  st->codec->sample_rate = 48000;
131  st->codec->bit_rate = 2 * 1 * 48000 * 8;
132  st->codec->block_align = 2 * 1;
133  st->codec->bits_per_coded_sample = 16;
134  break;
135  case 17:
137  st->codec->codec_id = CODEC_ID_AC3;
138  st->codec->channels = 2;
139  st->codec->sample_rate = 48000;
140  break;
141  // timecode tracks:
142  case 7:
143  case 8:
144  case 24:
147  break;
148  default:
151  break;
152  }
153  return s->nb_streams - 1;
154 }
155 
161 static void gxf_material_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
164  while (*len >= 2) {
165  GXFMatTag tag = avio_r8(pb);
166  int tlen = avio_r8(pb);
167  *len -= 2;
168  if (tlen > *len)
169  return;
170  *len -= tlen;
171  if (tlen == 4) {
172  uint32_t value = avio_rb32(pb);
173  if (tag == MAT_FIRST_FIELD)
174  si->first_field = value;
175  else if (tag == MAT_LAST_FIELD)
176  si->last_field = value;
177  } else
178  avio_skip(pb, tlen);
179  }
180 }
181 
187 static AVRational fps_tag2avr(int32_t fps) {
188  extern const AVRational avpriv_frame_rate_tab[];
189  if (fps < 1 || fps > 9) fps = 9;
190  return avpriv_frame_rate_tab[9 - fps]; // values have opposite order
191 }
192 
198 static AVRational fps_umf2avr(uint32_t flags) {
199  static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},
200  {25, 1}, {30000, 1001}};
201  int idx = av_log2((flags & 0x7c0) >> 6);
202  return map[idx];
203 }
204 
210 static void gxf_track_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
211  si->frames_per_second = (AVRational){0, 0};
212  si->fields_per_frame = 0;
213  while (*len >= 2) {
214  GXFTrackTag tag = avio_r8(pb);
215  int tlen = avio_r8(pb);
216  *len -= 2;
217  if (tlen > *len)
218  return;
219  *len -= tlen;
220  if (tlen == 4) {
221  uint32_t value = avio_rb32(pb);
222  if (tag == TRACK_FPS)
223  si->frames_per_second = fps_tag2avr(value);
224  else if (tag == TRACK_FPF && (value == 1 || value == 2))
225  si->fields_per_frame = value;
226  } else
227  avio_skip(pb, tlen);
228  }
229 }
230 
234 static void gxf_read_index(AVFormatContext *s, int pkt_len) {
235  AVIOContext *pb = s->pb;
236  AVStream *st = s->streams[0];
237  uint32_t fields_per_map = avio_rl32(pb);
238  uint32_t map_cnt = avio_rl32(pb);
239  int i;
240  pkt_len -= 8;
241  if (s->flags & AVFMT_FLAG_IGNIDX) {
242  avio_skip(pb, pkt_len);
243  return;
244  }
245  if (map_cnt > 1000) {
246  av_log(s, AV_LOG_ERROR, "too many index entries %u (%x)\n", map_cnt, map_cnt);
247  map_cnt = 1000;
248  }
249  if (pkt_len < 4 * map_cnt) {
250  av_log(s, AV_LOG_ERROR, "invalid index length\n");
251  avio_skip(pb, pkt_len);
252  return;
253  }
254  pkt_len -= 4 * map_cnt;
255  av_add_index_entry(st, 0, 0, 0, 0, 0);
256  for (i = 0; i < map_cnt; i++)
257  av_add_index_entry(st, (uint64_t)avio_rl32(pb) * 1024,
258  i * (uint64_t)fields_per_map + 1, 0, 0, 0);
259  avio_skip(pb, pkt_len);
260 }
261 
263  AVIOContext *pb = s->pb;
264  GXFPktType pkt_type;
265  int map_len;
266  int len;
267  AVRational main_timebase = {0, 0};
268  struct gxf_stream_info *si = s->priv_data;
269  int i;
270  if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
271  av_log(s, AV_LOG_ERROR, "map packet not found\n");
272  return 0;
273  }
274  map_len -= 2;
275  if (avio_r8(pb) != 0x0e0 || avio_r8(pb) != 0xff) {
276  av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");
277  return 0;
278  }
279  map_len -= 2;
280  len = avio_rb16(pb); // length of material data section
281  if (len > map_len) {
282  av_log(s, AV_LOG_ERROR, "material data longer than map data\n");
283  return 0;
284  }
285  map_len -= len;
286  gxf_material_tags(pb, &len, si);
287  avio_skip(pb, len);
288  map_len -= 2;
289  len = avio_rb16(pb); // length of track description
290  if (len > map_len) {
291  av_log(s, AV_LOG_ERROR, "track description longer than map data\n");
292  return 0;
293  }
294  map_len -= len;
295  while (len > 0) {
296  int track_type, track_id, track_len;
297  AVStream *st;
298  int idx;
299  len -= 4;
300  track_type = avio_r8(pb);
301  track_id = avio_r8(pb);
302  track_len = avio_rb16(pb);
303  len -= track_len;
304  gxf_track_tags(pb, &track_len, si);
305  avio_skip(pb, track_len);
306  if (!(track_type & 0x80)) {
307  av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);
308  continue;
309  }
310  track_type &= 0x7f;
311  if ((track_id & 0xc0) != 0xc0) {
312  av_log(s, AV_LOG_ERROR, "invalid track id %x\n", track_id);
313  continue;
314  }
315  track_id &= 0x3f;
316  idx = get_sindex(s, track_id, track_type);
317  if (idx < 0) continue;
318  st = s->streams[idx];
319  if (!main_timebase.num || !main_timebase.den) {
320  main_timebase.num = si->frames_per_second.den;
321  main_timebase.den = si->frames_per_second.num * 2;
322  }
323  st->start_time = si->first_field;
325  st->duration = si->last_field - si->first_field;
326  }
327  if (len < 0)
328  av_log(s, AV_LOG_ERROR, "invalid track description length specified\n");
329  if (map_len)
330  avio_skip(pb, map_len);
331  if (!parse_packet_header(pb, &pkt_type, &len)) {
332  av_log(s, AV_LOG_ERROR, "sync lost in header\n");
333  return -1;
334  }
335  if (pkt_type == PKT_FLT) {
336  gxf_read_index(s, len);
337  if (!parse_packet_header(pb, &pkt_type, &len)) {
338  av_log(s, AV_LOG_ERROR, "sync lost in header\n");
339  return -1;
340  }
341  }
342  if (pkt_type == PKT_UMF) {
343  if (len >= 0x39) {
344  AVRational fps;
345  len -= 0x39;
346  avio_skip(pb, 5); // preamble
347  avio_skip(pb, 0x30); // payload description
348  fps = fps_umf2avr(avio_rl32(pb));
349  if (!main_timebase.num || !main_timebase.den) {
350  // this may not always be correct, but simply the best we can get
351  main_timebase.num = fps.den;
352  main_timebase.den = fps.num * 2;
353  }
354  } else
355  av_log(s, AV_LOG_INFO, "UMF packet too short\n");
356  } else
357  av_log(s, AV_LOG_INFO, "UMF packet missing\n");
358  avio_skip(pb, len);
359  // set a fallback value, 60000/1001 is specified for audio-only files
360  // so use that regardless of why we do not know the video frame rate.
361  if (!main_timebase.num || !main_timebase.den)
362  main_timebase = (AVRational){1001, 60000};
363  for (i = 0; i < s->nb_streams; i++) {
364  AVStream *st = s->streams[i];
365  avpriv_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
366  }
367  return 0;
368 }
369 
370 #define READ_ONE() \
371  { \
372  if (!max_interval-- || pb->eof_reached) \
373  goto out; \
374  tmp = tmp << 8 | avio_r8(pb); \
375  }
376 
384 static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
385  uint32_t tmp;
386  uint64_t last_pos;
387  uint64_t last_found_pos = 0;
388  int cur_track;
389  int64_t cur_timestamp = AV_NOPTS_VALUE;
390  int len;
391  AVIOContext *pb = s->pb;
392  GXFPktType type;
393  tmp = avio_rb32(pb);
394 start:
395  while (tmp)
396  READ_ONE();
397  READ_ONE();
398  if (tmp != 1)
399  goto start;
400  last_pos = avio_tell(pb);
401  if (avio_seek(pb, -5, SEEK_CUR) < 0)
402  goto out;
403  if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
404  if (avio_seek(pb, last_pos, SEEK_SET) < 0)
405  goto out;
406  goto start;
407  }
408  avio_r8(pb);
409  cur_track = avio_r8(pb);
410  cur_timestamp = avio_rb32(pb);
411  last_found_pos = avio_tell(pb) - 16 - 6;
412  if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
413  if (avio_seek(pb, last_pos, SEEK_SET) >= 0)
414  goto start;
415  }
416 out:
417  if (last_found_pos)
418  avio_seek(pb, last_found_pos, SEEK_SET);
419  return cur_timestamp;
420 }
421 
422 static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
423  AVIOContext *pb = s->pb;
424  GXFPktType pkt_type;
425  int pkt_len;
426  struct gxf_stream_info *si = s->priv_data;
427 
428  while (!pb->eof_reached) {
429  AVStream *st;
430  int track_type, track_id, ret;
431  int field_nr, field_info, skip = 0;
432  int stream_index;
433  if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
434  if (!pb->eof_reached)
435  av_log(s, AV_LOG_ERROR, "sync lost\n");
436  return -1;
437  }
438  if (pkt_type == PKT_FLT) {
439  gxf_read_index(s, pkt_len);
440  continue;
441  }
442  if (pkt_type != PKT_MEDIA) {
443  avio_skip(pb, pkt_len);
444  continue;
445  }
446  if (pkt_len < 16) {
447  av_log(s, AV_LOG_ERROR, "invalid media packet length\n");
448  continue;
449  }
450  pkt_len -= 16;
451  track_type = avio_r8(pb);
452  track_id = avio_r8(pb);
453  stream_index = get_sindex(s, track_id, track_type);
454  if (stream_index < 0)
455  return stream_index;
456  st = s->streams[stream_index];
457  field_nr = avio_rb32(pb);
458  field_info = avio_rb32(pb);
459  avio_rb32(pb); // "timeline" field number
460  avio_r8(pb); // flags
461  avio_r8(pb); // reserved
462  if (st->codec->codec_id == CODEC_ID_PCM_S24LE ||
464  int first = field_info >> 16;
465  int last = field_info & 0xffff; // last is exclusive
466  int bps = av_get_bits_per_sample(st->codec->codec_id)>>3;
467  if (first <= last && last*bps <= pkt_len) {
468  avio_skip(pb, first*bps);
469  skip = pkt_len - last*bps;
470  pkt_len = (last-first)*bps;
471  } else
472  av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");
473  }
474  ret = av_get_packet(pb, pkt, pkt_len);
475  if (skip)
476  avio_skip(pb, skip);
477  pkt->stream_index = stream_index;
478  pkt->dts = field_nr;
479 
480  //set duration manually for DV or else lavf misdetects the frame rate
481  if (st->codec->codec_id == CODEC_ID_DVVIDEO)
482  pkt->duration = si->fields_per_frame;
483 
484  return ret;
485  }
486  return AVERROR(EIO);
487 }
488 
489 static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
490  int res = 0;
491  uint64_t pos;
492  uint64_t maxlen = 100 * 1024 * 1024;
493  AVStream *st = s->streams[0];
494  int64_t start_time = s->streams[stream_index]->start_time;
495  int64_t found;
496  int idx;
497  if (timestamp < start_time) timestamp = start_time;
498  idx = av_index_search_timestamp(st, timestamp - start_time,
500  if (idx < 0)
501  return -1;
502  pos = st->index_entries[idx].pos;
503  if (idx < st->nb_index_entries - 2)
504  maxlen = st->index_entries[idx + 2].pos - pos;
505  maxlen = FFMAX(maxlen, 200 * 1024);
506  res = avio_seek(s->pb, pos, SEEK_SET);
507  if (res < 0)
508  return res;
509  found = gxf_resync_media(s, maxlen, -1, timestamp);
510  if (FFABS(found - timestamp) > 4)
511  return -1;
512  return 0;
513 }
514 
515 static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
516  int64_t *pos, int64_t pos_limit) {
517  AVIOContext *pb = s->pb;
518  int64_t res;
519  if (avio_seek(pb, *pos, SEEK_SET) < 0)
520  return AV_NOPTS_VALUE;
521  res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
522  *pos = avio_tell(pb);
523  return res;
524 }
525 
527  .name = "gxf",
528  .long_name = NULL_IF_CONFIG_SMALL("GXF format"),
529  .priv_data_size = sizeof(struct gxf_stream_info),
530  .read_probe = gxf_probe,
531  .read_header = gxf_header,
532  .read_packet = gxf_packet,
533  .read_seek = gxf_seek,
534  .read_timestamp = gxf_read_timestamp,
535 };