1 /*
2 * MD STUDIO audio demuxer
3 *
4 * Copyright (c) 2009 Benjamin Larsson
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "libavutil/channel_layout.h"
24 #include "libavutil/intreadwrite.h"
25 #include "avformat.h"
26 #include "pcm.h"
27
28 #define AT1_SU_SIZE 212
29
aea_read_probe(const AVProbeData * p)30 static int aea_read_probe(const AVProbeData *p)
31 {
32 if (p->buf_size <= 2048+212)
33 return 0;
34
35 /* Magic is '00 08 00 00' in little-endian*/
36 if (AV_RL32(p->buf)==0x800) {
37 int ch, i;
38 ch = p->buf[264];
39
40 if (ch != 1 && ch != 2)
41 return 0;
42
43 /* Check so that the redundant bsm bytes and info bytes are valid
44 * the block size mode bytes have to be the same
45 * the info bytes have to be the same
46 */
47 for (i = 2048; i + 211 < p->buf_size; i+= 212) {
48 int bsm_s, bsm_e, inb_s, inb_e;
49 bsm_s = p->buf[0];
50 inb_s = p->buf[1];
51 inb_e = p->buf[210];
52 bsm_e = p->buf[211];
53
54 if (bsm_s != bsm_e || inb_s != inb_e)
55 return 0;
56 }
57 return AVPROBE_SCORE_MAX / 4 + 1;
58 }
59 return 0;
60 }
61
aea_read_header(AVFormatContext * s)62 static int aea_read_header(AVFormatContext *s)
63 {
64 AVStream *st = avformat_new_stream(s, NULL);
65 int channels;
66 if (!st)
67 return AVERROR(ENOMEM);
68
69 /* Parse the amount of channels and skip to pos 2048(0x800) */
70 avio_skip(s->pb, 264);
71 channels = avio_r8(s->pb);
72 avio_skip(s->pb, 1783);
73
74
75 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
76 st->codecpar->codec_id = AV_CODEC_ID_ATRAC1;
77 st->codecpar->sample_rate = 44100;
78 st->codecpar->bit_rate = 292000;
79
80 if (channels != 1 && channels != 2) {
81 av_log(s, AV_LOG_ERROR, "Channels %d not supported!\n", channels);
82 return AVERROR_INVALIDDATA;
83 }
84
85 av_channel_layout_default(&st->codecpar->ch_layout, channels);
86
87 st->codecpar->block_align = AT1_SU_SIZE * st->codecpar->ch_layout.nb_channels;
88 return 0;
89 }
90
aea_read_packet(AVFormatContext * s,AVPacket * pkt)91 static int aea_read_packet(AVFormatContext *s, AVPacket *pkt)
92 {
93 int ret = av_get_packet(s->pb, pkt, s->streams[0]->codecpar->block_align);
94
95 pkt->stream_index = 0;
96 if (ret <= 0)
97 return AVERROR(EIO);
98
99 return ret;
100 }
101
102 const AVInputFormat ff_aea_demuxer = {
103 .name = "aea",
104 .long_name = NULL_IF_CONFIG_SMALL("MD STUDIO audio"),
105 .read_probe = aea_read_probe,
106 .read_header = aea_read_header,
107 .read_packet = aea_read_packet,
108 .read_seek = ff_pcm_read_seek,
109 .flags = AVFMT_GENERIC_INDEX,
110 .extensions = "aea",
111 };
112