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oggparseskeleton.c
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1 /*
2  * Copyright (C) 2010 David Conrad
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "libavcodec/bytestream.h"
22 #include "avformat.h"
23 #include "internal.h"
24 #include "oggdec.h"
25 
26 static int skeleton_header(AVFormatContext *s, int idx)
27 {
28  struct ogg *ogg = s->priv_data;
29  struct ogg_stream *os = ogg->streams + idx;
30  AVStream *st = s->streams[idx];
31  uint8_t *buf = os->buf + os->pstart;
32  int version_major, version_minor;
33  int64_t start_num, start_den;
34  uint64_t start_granule;
35  int target_idx, start_time;
36 
37  strcpy(st->codec->codec_name, "skeleton");
39 
40  if ((os->flags & OGG_FLAG_EOS) && os->psize == 0)
41  return 1;
42 
43  if (os->psize < 8)
44  return -1;
45 
46  if (!strncmp(buf, "fishead", 8)) {
47  if (os->psize < 64)
48  return -1;
49 
50  version_major = AV_RL16(buf+8);
51  version_minor = AV_RL16(buf+10);
52 
53  if (version_major != 3 && version_major != 4) {
54  av_log(s, AV_LOG_WARNING, "Unknown skeleton version %d.%d\n",
55  version_major, version_minor);
56  return -1;
57  }
58 
59  // This is the overall start time. We use it for the start time of
60  // of the skeleton stream since if left unset lavf assumes 0,
61  // which we don't want since skeleton is timeless
62  // FIXME: the real meaning of this field is "start playback at
63  // this time which can be in the middle of a packet
64  start_num = AV_RL64(buf+12);
65  start_den = AV_RL64(buf+20);
66 
67  if (start_den > 0 && start_num > 0) {
68  int base_den;
69  av_reduce(&start_time, &base_den, start_num, start_den, INT_MAX);
70  avpriv_set_pts_info(st, 64, 1, base_den);
71  os->lastpts =
72  st->start_time = start_time;
73  }
74  } else if (!strncmp(buf, "fisbone", 8)) {
75  if (os->psize < 52)
76  return -1;
77 
78  target_idx = ogg_find_stream(ogg, AV_RL32(buf+12));
79  start_granule = AV_RL64(buf+36);
80  if (target_idx < 0) {
81  av_log(s, AV_LOG_WARNING, "Serial number in fisbone doesn't match any stream\n");
82  return 1;
83  }
84  os = ogg->streams + target_idx;
86  av_log(s, AV_LOG_WARNING, "Multiple fisbone for the same stream\n");
87  return 1;
88  }
89  if (start_granule != OGG_NOGRANULE_VALUE) {
91  }
92  }
93 
94  return 1;
95 }
96 
97 const struct ogg_codec ff_skeleton_codec = {
98  .magic = "fishead",
99  .magicsize = 8,
100  .header = skeleton_header,
101  .nb_header = 0,
102 };