2 * Maxis XA (.xa) File Demuxer
3 * Copyright (c) 2008 Robert Marston
5 * This file is part of FFmpeg.
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.
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.
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
24 * Maxis XA File Demuxer
25 * by Robert Marston (rmarston@gmail.com)
26 * for more information on the XA audio format see
27 * http://wiki.multimedia.cx/index.php?title=Maxis_XA
30 #include "libavutil/intreadwrite.h"
34 #define XA00_TAG MKTAG('X', 'A', 0, 0)
35 #define XAI0_TAG MKTAG('X', 'A', 'I', 0)
36 #define XAJ0_TAG MKTAG('X', 'A', 'J', 0)
38 typedef struct MaxisXADemuxContext
{
41 } MaxisXADemuxContext
;
43 static int xa_probe(AVProbeData
*p
)
45 int channels
, srate
, bits_per_sample
;
48 switch(AV_RL32(p
->buf
)) {
56 channels
= AV_RL16(p
->buf
+ 10);
57 srate
= AV_RL32(p
->buf
+ 12);
58 bits_per_sample
= AV_RL16(p
->buf
+ 22);
59 if (!channels
|| channels
> 8 || !srate
|| srate
> 192000 ||
60 bits_per_sample
< 4 || bits_per_sample
> 32)
62 return AVPROBE_SCORE_EXTENSION
;
65 static int xa_read_header(AVFormatContext
*s
)
67 MaxisXADemuxContext
*xa
= s
->priv_data
;
68 AVIOContext
*pb
= s
->pb
;
71 /*Set up the XA Audio Decoder*/
72 st
= avformat_new_stream(s
, NULL
);
74 return AVERROR(ENOMEM
);
76 st
->codec
->codec_type
= AVMEDIA_TYPE_AUDIO
;
77 st
->codec
->codec_id
= AV_CODEC_ID_ADPCM_EA_MAXIS_XA
;
78 avio_skip(pb
, 4); /* Skip the XA ID */
79 xa
->out_size
= avio_rl32(pb
);
80 avio_skip(pb
, 2); /* Skip the tag */
81 st
->codec
->channels
= avio_rl16(pb
);
82 st
->codec
->sample_rate
= avio_rl32(pb
);
83 avio_skip(pb
, 4); /* Skip average byte rate */
84 avio_skip(pb
, 2); /* Skip block align */
85 avio_skip(pb
, 2); /* Skip bits-per-sample */
87 if (!st
->codec
->channels
|| !st
->codec
->sample_rate
)
88 return AVERROR_INVALIDDATA
;
90 st
->codec
->bit_rate
= av_clip(15LL * st
->codec
->channels
* 8 *
91 st
->codec
->sample_rate
/ 28, 0, INT_MAX
);
93 avpriv_set_pts_info(st
, 64, 1, st
->codec
->sample_rate
);
99 static int xa_read_packet(AVFormatContext
*s
,
102 MaxisXADemuxContext
*xa
= s
->priv_data
;
103 AVStream
*st
= s
->streams
[0];
104 AVIOContext
*pb
= s
->pb
;
105 unsigned int packet_size
;
108 if (xa
->sent_bytes
>= xa
->out_size
)
110 /* 1 byte header and 14 bytes worth of samples * number channels per block */
111 packet_size
= 15*st
->codec
->channels
;
113 ret
= av_get_packet(pb
, pkt
, packet_size
);
117 pkt
->stream_index
= st
->index
;
118 xa
->sent_bytes
+= packet_size
;
124 AVInputFormat ff_xa_demuxer
= {
126 .long_name
= NULL_IF_CONFIG_SMALL("Maxis XA"),
127 .priv_data_size
= sizeof(MaxisXADemuxContext
),
128 .read_probe
= xa_probe
,
129 .read_header
= xa_read_header
,
130 .read_packet
= xa_read_packet
,