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oggparsecelt.c
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1 /*
2  * Xiph CELT parser for Ogg
3  * Copyright (c) 2011 Nicolas George
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 <string.h>
23 
24 #include "libavutil/intreadwrite.h"
25 #include "avformat.h"
26 #include "internal.h"
27 #include "oggdec.h"
28 
31 };
32 
33 static int celt_header(AVFormatContext *s, int idx)
34 {
35  struct ogg *ogg = s->priv_data;
36  struct ogg_stream *os = ogg->streams + idx;
37  AVStream *st = s->streams[idx];
38  struct oggcelt_private *priv = os->private;
39  uint8_t *p = os->buf + os->pstart;
40 
41  if (os->psize == 60 &&
43  /* Main header */
44 
45  uint32_t version, sample_rate, nb_channels;
46  uint32_t overlap, extra_headers;
47 
48  priv = av_malloc(sizeof(struct oggcelt_private));
49  if (!priv)
50  return AVERROR(ENOMEM);
51  if (ff_alloc_extradata(st->codec, 2 * sizeof(uint32_t)) < 0) {
52  av_free(priv);
53  return AVERROR(ENOMEM);
54  }
55  version = AV_RL32(p + 28);
56  /* unused header size field skipped */
57  sample_rate = AV_RL32(p + 36);
58  nb_channels = AV_RL32(p + 40);
59  overlap = AV_RL32(p + 48);
60  /* unused bytes per packet field skipped */
61  extra_headers = AV_RL32(p + 56);
65  st->codec->channels = nb_channels;
66  if (sample_rate)
67  avpriv_set_pts_info(st, 64, 1, sample_rate);
68  priv->extra_headers_left = 1 + extra_headers;
69  av_free(os->private);
70  os->private = priv;
71  AV_WL32(st->codec->extradata + 0, overlap);
72  AV_WL32(st->codec->extradata + 4, version);
73  return 1;
74  } else if (priv && priv->extra_headers_left) {
75  /* Extra headers (vorbiscomment) */
76 
77  ff_vorbis_comment(s, &st->metadata, p, os->psize, 1);
78  priv->extra_headers_left--;
79  return 1;
80  } else {
81  return 0;
82  }
83 }
84 
85 const struct ogg_codec ff_celt_codec = {
86  .magic = "CELT ",
87  .magicsize = 8,
88  .header = celt_header,
89  .nb_header = 2,
90 };