1 /*
2 * Maxis XA (.xa) File Demuxer
3 * Copyright (c) 2008 Robert Marston
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 /**
23 * @file
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
28 */
29
30 #include "libavutil/intreadwrite.h"
31 #include "avformat.h"
32 #include "internal.h"
33
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)
37
38 typedef struct MaxisXADemuxContext {
39 uint32_t out_size;
40 uint32_t sent_bytes;
41 } MaxisXADemuxContext;
42
xa_probe(const AVProbeData * p)43 static int xa_probe(const AVProbeData *p)
44 {
45 int channels, srate, bits_per_sample;
46 if (p->buf_size < 24)
47 return 0;
48 switch(AV_RL32(p->buf)) {
49 case XA00_TAG:
50 case XAI0_TAG:
51 case XAJ0_TAG:
52 break;
53 default:
54 return 0;
55 }
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)
61 return 0;
62 return AVPROBE_SCORE_EXTENSION;
63 }
64
xa_read_header(AVFormatContext * s)65 static int xa_read_header(AVFormatContext *s)
66 {
67 MaxisXADemuxContext *xa = s->priv_data;
68 AVIOContext *pb = s->pb;
69 AVStream *st;
70
71 /*Set up the XA Audio Decoder*/
72 st = avformat_new_stream(s, NULL);
73 if (!st)
74 return AVERROR(ENOMEM);
75
76 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
77 st->codecpar->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->codecpar->channels = avio_rl16(pb);
82 st->codecpar->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 */
86
87 if (!st->codecpar->channels || !st->codecpar->sample_rate)
88 return AVERROR_INVALIDDATA;
89
90 st->codecpar->bit_rate = av_clip(15LL * st->codecpar->channels * 8 *
91 st->codecpar->sample_rate / 28, 0, INT_MAX);
92
93 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
94 st->start_time = 0;
95
96 return 0;
97 }
98
xa_read_packet(AVFormatContext * s,AVPacket * pkt)99 static int xa_read_packet(AVFormatContext *s,
100 AVPacket *pkt)
101 {
102 MaxisXADemuxContext *xa = s->priv_data;
103 AVStream *st = s->streams[0];
104 AVIOContext *pb = s->pb;
105 unsigned int packet_size;
106 int ret;
107
108 if (xa->sent_bytes >= xa->out_size)
109 return AVERROR_EOF;
110 /* 1 byte header and 14 bytes worth of samples * number channels per block */
111 packet_size = 15*st->codecpar->channels;
112
113 ret = av_get_packet(pb, pkt, packet_size);
114 if(ret < 0)
115 return ret;
116
117 pkt->stream_index = st->index;
118 xa->sent_bytes += packet_size;
119 pkt->duration = 28;
120
121 return ret;
122 }
123
124 AVInputFormat ff_xa_demuxer = {
125 .name = "xa",
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,
131 };
132