1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*
* Maxis XA (.xa) File Demuxer
* Copyright (c) 2008 Robert Marston
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Maxis XA File Demuxer
* by Robert Marston (rmarston@gmail.com)
* for more information on the XA audio format see
* http://wiki.multimedia.cx/index.php?title=Maxis_XA
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#define XA00_TAG MKTAG('X', 'A', 0, 0)
#define XAI0_TAG MKTAG('X', 'A', 'I', 0)
#define XAJ0_TAG MKTAG('X', 'A', 'J', 0)
typedef struct MaxisXADemuxContext {
uint32_t out_size;
uint32_t sent_bytes;
} MaxisXADemuxContext;
static int xa_probe(const AVProbeData *p)
{
int channels, srate, bits_per_sample;
if (p->buf_size < 24)
return 0;
switch(AV_RL32(p->buf)) {
case XA00_TAG:
case XAI0_TAG:
case XAJ0_TAG:
break;
default:
return 0;
}
channels = AV_RL16(p->buf + 10);
srate = AV_RL32(p->buf + 12);
bits_per_sample = AV_RL16(p->buf + 22);
if (!channels || channels > 8 || !srate || srate > 192000 ||
bits_per_sample < 4 || bits_per_sample > 32)
return 0;
return AVPROBE_SCORE_EXTENSION;
}
static int xa_read_header(AVFormatContext *s)
{
MaxisXADemuxContext *xa = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *st;
/*Set up the XA Audio Decoder*/
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_ADPCM_EA_MAXIS_XA;
avio_skip(pb, 4); /* Skip the XA ID */
xa->out_size = avio_rl32(pb);
avio_skip(pb, 2); /* Skip the tag */
st->codecpar->ch_layout.nb_channels = avio_rl16(pb);
st->codecpar->sample_rate = avio_rl32(pb);
avio_skip(pb, 4); /* Skip average byte rate */
avio_skip(pb, 2); /* Skip block align */
avio_skip(pb, 2); /* Skip bits-per-sample */
if (!st->codecpar->ch_layout.nb_channels || !st->codecpar->sample_rate)
return AVERROR_INVALIDDATA;
st->codecpar->bit_rate = av_clip(15LL * st->codecpar->ch_layout.nb_channels * 8 *
st->codecpar->sample_rate / 28, 0, INT_MAX);
avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
st->start_time = 0;
return 0;
}
static int xa_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
MaxisXADemuxContext *xa = s->priv_data;
AVStream *st = s->streams[0];
AVIOContext *pb = s->pb;
unsigned int packet_size;
int ret;
if (xa->sent_bytes >= xa->out_size)
return AVERROR_EOF;
/* 1 byte header and 14 bytes worth of samples * number channels per block */
packet_size = 15*st->codecpar->ch_layout.nb_channels;
ret = av_get_packet(pb, pkt, packet_size);
if(ret < 0)
return ret;
pkt->stream_index = st->index;
xa->sent_bytes += packet_size;
pkt->duration = 28;
return ret;
}
const AVInputFormat ff_xa_demuxer = {
.name = "xa",
.long_name = NULL_IF_CONFIG_SMALL("Maxis XA"),
.priv_data_size = sizeof(MaxisXADemuxContext),
.read_probe = xa_probe,
.read_header = xa_read_header,
.read_packet = xa_read_packet,
};
|
