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2ba45a60 DM |
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->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 */ | |
86 | ||
87 | if (!st->codec->channels || !st->codec->sample_rate) | |
88 | return AVERROR_INVALIDDATA; | |
89 | ||
90 | st->codec->bit_rate = av_clip(15LL * st->codec->channels * 8 * | |
91 | st->codec->sample_rate / 28, 0, INT_MAX); | |
92 | ||
93 | avpriv_set_pts_info(st, 64, 1, st->codec->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->codec->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 | }; |