ILIAS  release_5-2 Revision v5.2.25-18-g3f80b828510
Public Member Functions
GetId3\Module\Audio\Lpac Class Reference

GetId3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g //. More...

+ Inheritance diagram for GetId3\Module\Audio\Lpac:
+ Collaboration diagram for GetId3\Module\Audio\Lpac:

Public Member Functions

 analyze ()
 
- Public Member Functions inherited from GetId3\Handler\BaseHandler
 __construct (GetId3Core $getid3, $call_module=null)
 
 analyze ()
 Analyze from file pointer. More...
 
 AnalyzeString (&$string)
 Analyze from string instead. More...
 
 saveAttachment (&$ThisFileInfoIndex, $filename, $offset, $length)
 

Additional Inherited Members

- Protected Member Functions inherited from GetId3\Handler\BaseHandler
 ftell ()
 
 fread ($bytes)
 
 fseek ($bytes, $whence=SEEK_SET)
 
 feof ()
 
 isDependencyFor ($module)
 
 error ($text)
 
 warning ($text)
 
- Protected Attributes inherited from GetId3\Handler\BaseHandler
 $getid3
 
 $data_string_flag = false
 
 $data_string = ''
 
 $data_string_position = 0
 
 $data_string_length = 0
 

Detailed Description

GetId3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g //.

module for analyzing LPAC Audio files

Author
James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g http://www.getid3.org

Definition at line 31 of file Lpac.php.

Member Function Documentation

◆ analyze()

GetId3\Module\Audio\Lpac::analyze ( )
Returns
boolean

Reimplemented from GetId3\Handler\BaseHandler.

Definition at line 38 of file Lpac.php.

39 {
40 $info = &$this->getid3->info;
41
42 fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
43 $LPACheader = fread($this->getid3->fp, 14);
44 if (substr($LPACheader, 0, 4) != 'LPAC') {
45 $info['error'][] = 'Expected "LPAC" at offset '.$info['avdataoffset'].', found "'.$StreamMarker.'"';
46
47 return false;
48 }
49 $info['avdataoffset'] += 14;
50
51 $info['fileformat'] = 'lpac';
52 $info['audio']['dataformat'] = 'lpac';
53 $info['audio']['lossless'] = true;
54 $info['audio']['bitrate_mode'] = 'vbr';
55
56 $info['lpac']['file_version'] = Helper::BigEndian2Int(substr($LPACheader, 4, 1));
57 $flags['audio_type'] = Helper::BigEndian2Int(substr($LPACheader, 5, 1));
58 $info['lpac']['total_samples']= Helper::BigEndian2Int(substr($LPACheader, 6, 4));
59 $flags['parameters'] = Helper::BigEndian2Int(substr($LPACheader, 10, 4));
60
61 $info['lpac']['flags']['is_wave'] = (bool) ($flags['audio_type'] & 0x40);
62 $info['lpac']['flags']['stereo'] = (bool) ($flags['audio_type'] & 0x04);
63 $info['lpac']['flags']['24_bit'] = (bool) ($flags['audio_type'] & 0x02);
64 $info['lpac']['flags']['16_bit'] = (bool) ($flags['audio_type'] & 0x01);
65
66 if ($info['lpac']['flags']['24_bit'] && $info['lpac']['flags']['16_bit']) {
67 $info['warning'][] = '24-bit and 16-bit flags cannot both be set';
68 }
69
70 $info['lpac']['flags']['fast_compress'] = (bool) ($flags['parameters'] & 0x40000000);
71 $info['lpac']['flags']['random_access'] = (bool) ($flags['parameters'] & 0x08000000);
72 $info['lpac']['block_length'] = pow(2, (($flags['parameters'] & 0x07000000) >> 24)) * 256;
73 $info['lpac']['flags']['adaptive_prediction_order'] = (bool) ($flags['parameters'] & 0x00800000);
74 $info['lpac']['flags']['adaptive_quantization'] = (bool) ($flags['parameters'] & 0x00400000);
75 $info['lpac']['flags']['joint_stereo'] = (bool) ($flags['parameters'] & 0x00040000);
76 $info['lpac']['quantization'] = ($flags['parameters'] & 0x00001F00) >> 8;
77 $info['lpac']['max_prediction_order'] = ($flags['parameters'] & 0x0000003F);
78
79 if ($info['lpac']['flags']['fast_compress'] && ($info['lpac']['max_prediction_order'] != 3)) {
80 $info['warning'][] = 'max_prediction_order expected to be "3" if fast_compress is true, actual value is "'.$info['lpac']['max_prediction_order'].'"';
81 }
82 switch ($info['lpac']['file_version']) {
83 case 6:
84 if ($info['lpac']['flags']['adaptive_quantization']) {
85 $info['warning'][] = 'adaptive_quantization expected to be false in LPAC file stucture v6, actually true';
86 }
87 if ($info['lpac']['quantization'] != 20) {
88 $info['warning'][] = 'Quantization expected to be 20 in LPAC file stucture v6, actually '.$info['lpac']['flags']['Q'];
89 }
90 break;
91
92 default:
93 //$info['warning'][] = 'This version of GetId3Core() ['.$this->getid3->version().'] only supports LPAC file format version 6, this file is version '.$info['lpac']['file_version'].' - please report to info@getid3.org';
94 break;
95 }
96
97 $getid3_temp = new GetId3Core();
98 $getid3_temp->openfile($this->getid3->filename);
99 $getid3_temp->info = $info;
100 $getid3_riff = new Riff($getid3_temp);
101 $getid3_riff->analyze();
102 $info['avdataoffset'] = $getid3_temp->info['avdataoffset'];
103 $info['riff'] = $getid3_temp->info['riff'];
104 $info['error'] = $getid3_temp->info['error'];
105 $info['warning'] = $getid3_temp->info['warning'];
106 $info['lpac']['comments']['comment'] = $getid3_temp->info['comments'];
107 $info['audio']['sample_rate'] = $getid3_temp->info['audio']['sample_rate'];
108 unset($getid3_temp, $getid3_riff);
109
110 $info['audio']['channels'] = ($info['lpac']['flags']['stereo'] ? 2 : 1);
111
112 if ($info['lpac']['flags']['24_bit']) {
113 $info['audio']['bits_per_sample'] = $info['riff']['audio'][0]['bits_per_sample'];
114 } elseif ($info['lpac']['flags']['16_bit']) {
115 $info['audio']['bits_per_sample'] = 16;
116 } else {
117 $info['audio']['bits_per_sample'] = 8;
118 }
119
120 if ($info['lpac']['flags']['fast_compress']) {
121 // fast
122 $info['audio']['encoder_options'] = '-1';
123 } else {
124 switch ($info['lpac']['max_prediction_order']) {
125 case 20: // simple
126 $info['audio']['encoder_options'] = '-2';
127 break;
128 case 30: // medium
129 $info['audio']['encoder_options'] = '-3';
130 break;
131 case 40: // high
132 $info['audio']['encoder_options'] = '-4';
133 break;
134 case 60: // extrahigh
135 $info['audio']['encoder_options'] = '-5';
136 break;
137 }
138 }
139
140 $info['playtime_seconds'] = $info['lpac']['total_samples'] / $info['audio']['sample_rate'];
141 $info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
142
143 return true;
144 }
GetId3\Handler\BaseHandler\fseek
fseek($bytes, $whence=SEEK_SET)
Definition: BaseHandler.php:148
GetId3\Lib\Helper\BigEndian2Int
static BigEndian2Int($byteword, $synchsafe=false, $signed=false)
Definition: Helper.php:374
$info
$info
Definition: example_052.php:80

References $info, GetId3\Lib\Helper\BigEndian2Int(), GetId3\Handler\BaseHandler\fread(), and GetId3\Handler\BaseHandler\fseek().

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The documentation for this class was generated from the following file: