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
30static int aea_read_probe(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 bsm_s, bsm_e, inb_s, inb_e, ch;
38        ch    = p->buf[264];
39        bsm_s = p->buf[2048];
40        inb_s = p->buf[2048+1];
41        inb_e = p->buf[2048+210];
42        bsm_e = p->buf[2048+211];
43
44        if (ch != 1 && ch != 2)
45            return 0;
46
47        /* Check so that the redundant bsm bytes and info bytes are valid
48         * the block size mode bytes have to be the same
49         * the info bytes have to be the same
50         */
51        if (bsm_s == bsm_e && inb_s == inb_e)
52            return AVPROBE_SCORE_MAX / 4 + 1;
53    }
54    return 0;
55}
56
57static int aea_read_header(AVFormatContext *s)
58{
59    AVStream *st = avformat_new_stream(s, NULL);
60    if (!st)
61        return AVERROR(ENOMEM);
62
63    /* Parse the amount of channels and skip to pos 2048(0x800) */
64    avio_skip(s->pb, 264);
65    st->codec->channels = avio_r8(s->pb);
66    avio_skip(s->pb, 1783);
67
68
69    st->codec->codec_type     = AVMEDIA_TYPE_AUDIO;
70    st->codec->codec_id       = AV_CODEC_ID_ATRAC1;
71    st->codec->sample_rate    = 44100;
72    st->codec->bit_rate       = 292000;
73
74    if (st->codec->channels != 1 && st->codec->channels != 2) {
75        av_log(s,AV_LOG_ERROR,"Channels %d not supported!\n",st->codec->channels);
76        return -1;
77    }
78
79    st->codec->channel_layout = (st->codec->channels == 1) ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;
80
81    st->codec->block_align = AT1_SU_SIZE * st->codec->channels;
82    return 0;
83}
84
85static int aea_read_packet(AVFormatContext *s, AVPacket *pkt)
86{
87    int ret = av_get_packet(s->pb, pkt, s->streams[0]->codec->block_align);
88
89    pkt->stream_index = 0;
90    if (ret <= 0)
91        return AVERROR(EIO);
92
93    return ret;
94}
95
96AVInputFormat ff_aea_demuxer = {
97    .name           = "aea",
98    .long_name      = NULL_IF_CONFIG_SMALL("MD STUDIO audio"),
99    .read_probe     = aea_read_probe,
100    .read_header    = aea_read_header,
101    .read_packet    = aea_read_packet,
102    .read_seek      = ff_pcm_read_seek,
103    .flags          = AVFMT_GENERIC_INDEX,
104    .extensions     = "aea",
105};
106