1 /*
2 * CRYO APC audio format demuxer
3 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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/channel_layout.h"
25 #include "avformat.h"
26 #include "demux.h"
27
apc_probe(const AVProbeData *p)28 static int apc_probe(const AVProbeData *p)
29 {
30 if (!strncmp(p->buf, "CRYO_APC", 8))
31 return AVPROBE_SCORE_MAX;
32
33 return 0;
34 }
35
apc_read_header(AVFormatContext *s)36 static int apc_read_header(AVFormatContext *s)
37 {
38 AVIOContext *pb = s->pb;
39 AVStream *st;
40 int ret;
41 int channels;
42
43 avio_rl32(pb); /* CRYO */
44 avio_rl32(pb); /* _APC */
45 avio_rl32(pb); /* 1.20 */
46
47 st = avformat_new_stream(s, NULL);
48 if (!st)
49 return AVERROR(ENOMEM);
50
51 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
52 st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
53
54 avio_rl32(pb); /* number of samples */
55 st->codecpar->sample_rate = avio_rl32(pb);
56
57 /* initial predictor values for adpcm decoder */
58 if ((ret = ff_get_extradata(s, st->codecpar, pb, 2 * 4)) < 0)
59 return ret;
60
61 channels = !!avio_rl32(pb) + 1;
62 av_channel_layout_default(&st->codecpar->ch_layout, channels);
63
64 st->codecpar->bits_per_coded_sample = 4;
65 st->codecpar->bit_rate = (int64_t)st->codecpar->bits_per_coded_sample * channels
66 * st->codecpar->sample_rate;
67 st->codecpar->block_align = 1;
68
69 return 0;
70 }
71
72 #define MAX_READ_SIZE 4096
73
apc_read_packet(AVFormatContext *s, AVPacket *pkt)74 static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)
75 {
76 if (av_get_packet(s->pb, pkt, MAX_READ_SIZE) <= 0)
77 return AVERROR(EIO);
78 pkt->stream_index = 0;
79 return 0;
80 }
81
82 const AVInputFormat ff_apc_demuxer = {
83 .name = "apc",
84 .long_name = NULL_IF_CONFIG_SMALL("CRYO APC"),
85 .read_probe = apc_probe,
86 .read_header = apc_read_header,
87 .read_packet = apc_read_packet,
88 };
89