ILIAS  release_5-1 Revision 5.0.0-5477-g43f3e3fab5f
module.audio.lpac.php
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1<?php
4// available at http://getid3.sourceforge.net //
5// or http://www.getid3.org //
7// See readme.txt for more details //
9// //
10// module.audio.lpac.php //
11// module for analyzing LPAC Audio files //
12// dependencies: module.audio-video.riff.php //
13// ///
15
16getid3_lib::IncludeDependency(GETID3_INCLUDEPATH.'module.audio-video.riff.php', __FILE__, true);
17
18class getid3_lpac
19{
20
21 function getid3_lpac(&$fd, &$ThisFileInfo) {
22
23 fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
24 $LPACheader = fread($fd, 14);
25 if (substr($LPACheader, 0, 4) != 'LPAC') {
26 $ThisFileInfo['error'][] = 'Expected "LPAC" at offset '.$ThisFileInfo['avdataoffset'].', found "'.$StreamMarker.'"';
27 return false;
28 }
29 $ThisFileInfo['avdataoffset'] += 14;
30
31 $ThisFileInfo['fileformat'] = 'lpac';
32 $ThisFileInfo['audio']['dataformat'] = 'lpac';
33 $ThisFileInfo['audio']['lossless'] = true;
34 $ThisFileInfo['audio']['bitrate_mode'] = 'vbr';
35
36 $ThisFileInfo['lpac']['file_version'] = getid3_lib::BigEndian2Int(substr($LPACheader, 4, 1));
37 $flags['audio_type'] = getid3_lib::BigEndian2Int(substr($LPACheader, 5, 1));
38 $ThisFileInfo['lpac']['total_samples']= getid3_lib::BigEndian2Int(substr($LPACheader, 6, 4));
39 $flags['parameters'] = getid3_lib::BigEndian2Int(substr($LPACheader, 10, 4));
40
41 $ThisFileInfo['lpac']['flags']['is_wave'] = (bool) ($flags['audio_type'] & 0x40);
42 $ThisFileInfo['lpac']['flags']['stereo'] = (bool) ($flags['audio_type'] & 0x04);
43 $ThisFileInfo['lpac']['flags']['24_bit'] = (bool) ($flags['audio_type'] & 0x02);
44 $ThisFileInfo['lpac']['flags']['16_bit'] = (bool) ($flags['audio_type'] & 0x01);
45
46 if ($ThisFileInfo['lpac']['flags']['24_bit'] && $ThisFileInfo['lpac']['flags']['16_bit']) {
47 $ThisFileInfo['warning'][] = '24-bit and 16-bit flags cannot both be set';
48 }
49
50 $ThisFileInfo['lpac']['flags']['fast_compress'] = (bool) ($flags['parameters'] & 0x40000000);
51 $ThisFileInfo['lpac']['flags']['random_access'] = (bool) ($flags['parameters'] & 0x08000000);
52 $ThisFileInfo['lpac']['block_length'] = pow(2, (($flags['parameters'] & 0x07000000) >> 24)) * 256;
53 $ThisFileInfo['lpac']['flags']['adaptive_prediction_order'] = (bool) ($flags['parameters'] & 0x00800000);
54 $ThisFileInfo['lpac']['flags']['adaptive_quantization'] = (bool) ($flags['parameters'] & 0x00400000);
55 $ThisFileInfo['lpac']['flags']['joint_stereo'] = (bool) ($flags['parameters'] & 0x00040000);
56 $ThisFileInfo['lpac']['quantization'] = ($flags['parameters'] & 0x00001F00) >> 8;
57 $ThisFileInfo['lpac']['max_prediction_order'] = ($flags['parameters'] & 0x0000003F);
58
59 if ($ThisFileInfo['lpac']['flags']['fast_compress'] && ($ThisFileInfo['lpac']['max_prediction_order'] != 3)) {
60 $ThisFileInfo['warning'][] = 'max_prediction_order expected to be "3" if fast_compress is true, actual value is "'.$ThisFileInfo['lpac']['max_prediction_order'].'"';
61 }
62 switch ($ThisFileInfo['lpac']['file_version']) {
63 case 6:
64 if ($ThisFileInfo['lpac']['flags']['adaptive_quantization']) {
65 $ThisFileInfo['warning'][] = 'adaptive_quantization expected to be false in LPAC file stucture v6, actually true';
66 }
67 if ($ThisFileInfo['lpac']['quantization'] != 20) {
68 $ThisFileInfo['warning'][] = 'Quantization expected to be 20 in LPAC file stucture v6, actually '.$ThisFileInfo['lpac']['flags']['Q'];
69 }
70 break;
71
72 default:
73 //$ThisFileInfo['warning'][] = 'This version of getID3() only supports LPAC file format version 6, this file is version '.$ThisFileInfo['lpac']['file_version'].' - please report to info@getid3.org';
74 break;
75 }
76
77 $dummy = $ThisFileInfo;
78 $riff = new getid3_riff($fd, $dummy);
79 $ThisFileInfo['avdataoffset'] = $dummy['avdataoffset'];
80 $ThisFileInfo['riff'] = $dummy['riff'];
81 $ThisFileInfo['error'] = $dummy['error'];
82 $ThisFileInfo['warning'] = $dummy['warning'];
83 $ThisFileInfo['lpac']['comments']['comment'] = $dummy['comments'];
84 $ThisFileInfo['audio']['sample_rate'] = $dummy['audio']['sample_rate'];
85
86 $ThisFileInfo['audio']['channels'] = ($ThisFileInfo['lpac']['flags']['stereo'] ? 2 : 1);
87
88 if ($ThisFileInfo['lpac']['flags']['24_bit']) {
89 $ThisFileInfo['audio']['bits_per_sample'] = $ThisFileInfo['riff']['audio'][0]['bits_per_sample'];
90 } elseif ($ThisFileInfo['lpac']['flags']['16_bit']) {
91 $ThisFileInfo['audio']['bits_per_sample'] = 16;
92 } else {
93 $ThisFileInfo['audio']['bits_per_sample'] = 8;
94 }
95
96 if ($ThisFileInfo['lpac']['flags']['fast_compress']) {
97 // fast
98 $ThisFileInfo['audio']['encoder_options'] = '-1';
99 } else {
100 switch ($ThisFileInfo['lpac']['max_prediction_order']) {
101 case 20: // simple
102 $ThisFileInfo['audio']['encoder_options'] = '-2';
103 break;
104 case 30: // medium
105 $ThisFileInfo['audio']['encoder_options'] = '-3';
106 break;
107 case 40: // high
108 $ThisFileInfo['audio']['encoder_options'] = '-4';
109 break;
110 case 60: // extrahigh
111 $ThisFileInfo['audio']['encoder_options'] = '-5';
112 break;
113 }
114 }
115
116 $ThisFileInfo['playtime_seconds'] = $ThisFileInfo['lpac']['total_samples'] / $ThisFileInfo['audio']['sample_rate'];
117 $ThisFileInfo['audio']['bitrate'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['playtime_seconds'];
118
119 return true;
120 }
121
122}
123
124
125?>
getid3_handler\fseek
fseek($bytes, $whence=SEEK_SET)
Definition: getid3.php:1697
getid3_handler\fread
fread($bytes)
Definition: getid3.php:1685
getid3_lib\IncludeDependency
IncludeDependency($filename, $sourcefile, $DieOnFailure=false)
Definition: getid3.lib.php:1301
getid3_lib\BigEndian2Int
BigEndian2Int($byteword, $synchsafe=false, $signed=false)
Definition: getid3.lib.php:234
getid3_lpac
Definition: module.audio.lpac.php:19
getid3_lpac\getid3_lpac
getid3_lpac(&$fd, &$ThisFileInfo)
Definition: module.audio.lpac.php:21
getid3_riff
Definition: module.audio-video.riff.php:22