/libavformat/oggparsecelt.c

 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
29struct oggcelt_private {
30    int extra_headers_left;
31};
32
33static 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    int ret;
41
42    if (os->psize == 60 &&
43        !memcmp(p, ff_celt_codec.magic, ff_celt_codec.magicsize)) {
44        /* Main header */
45
46        uint32_t version, sample_rate, nb_channels;
47        uint32_t overlap, extra_headers;
48
49        priv = av_malloc(sizeof(struct oggcelt_private));
50        if (!priv)
51            return AVERROR(ENOMEM);
52        ret = ff_alloc_extradata(st->codecpar, 2 * sizeof(uint32_t));
53        if (ret < 0) {
54            av_free(priv);
55            return ret;
56        }
57        version          = AV_RL32(p + 28);
58        /* unused header size field skipped */
59        sample_rate      = AV_RL32(p + 36);
60        nb_channels      = AV_RL32(p + 40);
61        overlap          = AV_RL32(p + 48);
62        /* unused bytes per packet field skipped */
63        extra_headers    = AV_RL32(p + 56);
64        st->codecpar->codec_type     = AVMEDIA_TYPE_AUDIO;
65        st->codecpar->codec_id       = AV_CODEC_ID_CELT;
66        st->codecpar->sample_rate    = sample_rate;
67        st->codecpar->channels       = nb_channels;
68        if (sample_rate)
69            avpriv_set_pts_info(st, 64, 1, sample_rate);
70
71        if (os->private) {
72            av_free(priv);
73            priv = os->private;
74        }
75        os->private = priv;
76        priv->extra_headers_left  = 1 + extra_headers;
77
78        AV_WL32(st->codecpar->extradata + 0, overlap);
79        AV_WL32(st->codecpar->extradata + 4, version);
80        return 1;
81    } else if (priv && priv->extra_headers_left) {
82        /* Extra headers (vorbiscomment) */
83
84        ff_vorbis_stream_comment(s, st, p, os->psize);
85        priv->extra_headers_left--;
86        return 1;
87    } else {
88        return 0;
89    }
90}
91
92const struct ogg_codec ff_celt_codec = {
93    .magic     = "CELT    ",
94    .magicsize = 8,
95    .header    = celt_header,
96    .nb_header = 2,
97};