blob: 810e0c0197af39e56c9f04139210e5134baefff1
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 | static int xa_probe(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 | |
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 | |
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 |