Line data Source code
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 :
43 6217 : static int xa_probe(AVProbeData *p)
44 : {
45 : int channels, srate, bits_per_sample;
46 6217 : if (p->buf_size < 24)
47 0 : return 0;
48 6217 : switch(AV_RL32(p->buf)) {
49 2 : case XA00_TAG:
50 : case XAI0_TAG:
51 : case XAJ0_TAG:
52 2 : break;
53 6215 : default:
54 6215 : return 0;
55 : }
56 2 : channels = AV_RL16(p->buf + 10);
57 2 : srate = AV_RL32(p->buf + 12);
58 2 : bits_per_sample = AV_RL16(p->buf + 22);
59 2 : if (!channels || channels > 8 || !srate || srate > 192000 ||
60 2 : bits_per_sample < 4 || bits_per_sample > 32)
61 0 : return 0;
62 2 : return AVPROBE_SCORE_EXTENSION;
63 : }
64 :
65 2 : static int xa_read_header(AVFormatContext *s)
66 : {
67 2 : MaxisXADemuxContext *xa = s->priv_data;
68 2 : AVIOContext *pb = s->pb;
69 : AVStream *st;
70 :
71 : /*Set up the XA Audio Decoder*/
72 2 : st = avformat_new_stream(s, NULL);
73 2 : if (!st)
74 0 : return AVERROR(ENOMEM);
75 :
76 2 : st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
77 2 : st->codecpar->codec_id = AV_CODEC_ID_ADPCM_EA_MAXIS_XA;
78 2 : avio_skip(pb, 4); /* Skip the XA ID */
79 2 : xa->out_size = avio_rl32(pb);
80 2 : avio_skip(pb, 2); /* Skip the tag */
81 2 : st->codecpar->channels = avio_rl16(pb);
82 2 : st->codecpar->sample_rate = avio_rl32(pb);
83 2 : avio_skip(pb, 4); /* Skip average byte rate */
84 2 : avio_skip(pb, 2); /* Skip block align */
85 2 : avio_skip(pb, 2); /* Skip bits-per-sample */
86 :
87 2 : if (!st->codecpar->channels || !st->codecpar->sample_rate)
88 0 : return AVERROR_INVALIDDATA;
89 :
90 6 : st->codecpar->bit_rate = av_clip(15LL * st->codecpar->channels * 8 *
91 4 : st->codecpar->sample_rate / 28, 0, INT_MAX);
92 :
93 2 : avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
94 2 : st->start_time = 0;
95 :
96 2 : return 0;
97 : }
98 :
99 100 : static int xa_read_packet(AVFormatContext *s,
100 : AVPacket *pkt)
101 : {
102 100 : MaxisXADemuxContext *xa = s->priv_data;
103 100 : AVStream *st = s->streams[0];
104 100 : AVIOContext *pb = s->pb;
105 : unsigned int packet_size;
106 : int ret;
107 :
108 100 : if (xa->sent_bytes >= xa->out_size)
109 0 : return AVERROR_EOF;
110 : /* 1 byte header and 14 bytes worth of samples * number channels per block */
111 100 : packet_size = 15*st->codecpar->channels;
112 :
113 100 : ret = av_get_packet(pb, pkt, packet_size);
114 100 : if(ret < 0)
115 0 : return ret;
116 :
117 100 : pkt->stream_index = st->index;
118 100 : xa->sent_bytes += packet_size;
119 100 : pkt->duration = 28;
120 :
121 100 : 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 : };
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