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oggparsedirac.c
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1 /*
2  * Copyright (C) 2008 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/get_bits.h"
22 #include "libavcodec/dirac.h"
23 #include "avformat.h"
24 #include "internal.h"
25 #include "oggdec.h"
26 
27 static int dirac_header(AVFormatContext *s, int idx)
28 {
29  struct ogg *ogg = s->priv_data;
30  struct ogg_stream *os = ogg->streams + idx;
31  AVStream *st = s->streams[idx];
32  dirac_source_params source;
33  GetBitContext gb;
34 
35  // already parsed the header
36  if (st->codec->codec_id == AV_CODEC_ID_DIRAC)
37  return 0;
38 
39  init_get_bits(&gb, os->buf + os->pstart + 13, (os->psize - 13) * 8);
40  if (avpriv_dirac_parse_sequence_header(st->codec, &gb, &source) < 0)
41  return -1;
42 
43  st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
44  st->codec->codec_id = AV_CODEC_ID_DIRAC;
45  // dirac in ogg always stores timestamps as though the video were interlaced
46  avpriv_set_pts_info(st, 64, st->codec->time_base.num, 2*st->codec->time_base.den);
47  return 1;
48 }
49 
50 // various undocument things: granule is signed (only for dirac!)
51 static uint64_t dirac_gptopts(AVFormatContext *s, int idx, uint64_t granule,
52  int64_t *dts_out)
53 {
54  int64_t gp = granule;
55  struct ogg *ogg = s->priv_data;
56  struct ogg_stream *os = ogg->streams + idx;
57 
58  unsigned dist = ((gp >> 14) & 0xff00) | (gp & 0xff);
59  int64_t dts = (gp >> 31);
60  int64_t pts = dts + ((gp >> 9) & 0x1fff);
61 
62  if (!dist)
63  os->pflags |= AV_PKT_FLAG_KEY;
64 
65  if (dts_out)
66  *dts_out = dts;
67 
68  return pts;
69 }
70 
71 static int old_dirac_header(AVFormatContext *s, int idx)
72 {
73  struct ogg *ogg = s->priv_data;
74  struct ogg_stream *os = ogg->streams + idx;
75  AVStream *st = s->streams[idx];
76  uint8_t *buf = os->buf + os->pstart;
77 
78  if (buf[0] != 'K')
79  return 0;
80 
81  st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
82  st->codec->codec_id = AV_CODEC_ID_DIRAC;
83  avpriv_set_pts_info(st, 64, AV_RB32(buf+12), AV_RB32(buf+8));
84  return 1;
85 }
86 
87 static uint64_t old_dirac_gptopts(AVFormatContext *s, int idx, uint64_t gp,
88  int64_t *dts)
89 {
90  struct ogg *ogg = s->priv_data;
91  struct ogg_stream *os = ogg->streams + idx;
92  uint64_t iframe = gp >> 30;
93  uint64_t pframe = gp & 0x3fffffff;
94 
95  if (!pframe)
96  os->pflags |= AV_PKT_FLAG_KEY;
97 
98  return iframe + pframe;
99 }
100 
101 const struct ogg_codec ff_dirac_codec = {
102  .magic = "BBCD\0",
103  .magicsize = 5,
104  .header = dirac_header,
105  .gptopts = dirac_gptopts,
106  .granule_is_start = 1,
107  .nb_header = 1,
108 };
109 
110 const struct ogg_codec ff_old_dirac_codec = {
111  .magic = "KW-DIRAC",
112  .magicsize = 8,
113  .header = old_dirac_header,
114  .gptopts = old_dirac_gptopts,
115  .granule_is_start = 1,
116  .nb_header = 1,
117 };
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