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module.audio.avr.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.avr.php //
11 // module for analyzing AVR Audio files //
12 // dependencies: NONE //
13 // ///
15 
16 
17 class getid3_avr
18 {
19 
20  function getid3_avr(&$fd, &$ThisFileInfo) {
21 
22  // http://cui.unige.ch/OSG/info/AudioFormats/ap11.html
23  // http://www.btinternet.com/~AnthonyJ/Atari/programming/avr_format.html
24  // offset type length name comments
25  // ---------------------------------------------------------------------
26  // 0 char 4 ID format ID == "2BIT"
27  // 4 char 8 name sample name (unused space filled with 0)
28  // 12 short 1 mono/stereo 0=mono, -1 (0xFFFF)=stereo
29  // With stereo, samples are alternated,
30  // the first voice is the left :
31  // (LRLRLRLRLRLRLRLRLR...)
32  // 14 short 1 resolution 8, 12 or 16 (bits)
33  // 16 short 1 signed or not 0=unsigned, -1 (0xFFFF)=signed
34  // 18 short 1 loop or not 0=no loop, -1 (0xFFFF)=loop on
35  // 20 short 1 MIDI note 0xFFnn, where 0 <= nn <= 127
36  // 0xFFFF means "no MIDI note defined"
37  // 22 byte 1 Replay speed Frequence in the Replay software
38  // 0=5.485 Khz, 1=8.084 Khz, 2=10.971 Khz,
39  // 3=16.168 Khz, 4=21.942 Khz, 5=32.336 Khz
40  // 6=43.885 Khz, 7=47.261 Khz
41  // -1 (0xFF)=no defined Frequence
42  // 23 byte 3 sample rate in Hertz
43  // 26 long 1 size in bytes (2 * bytes in stereo)
44  // 30 long 1 loop begin 0 for no loop
45  // 34 long 1 loop size equal to 'size' for no loop
46  // 38 short 2 Reserved, MIDI keyboard split */
47  // 40 short 2 Reserved, sample compression */
48  // 42 short 2 Reserved */
49  // 44 char 20; Additional filename space, used if (name[7] != 0)
50  // 64 byte 64 user data
51  // 128 bytes ? sample data (12 bits samples are coded on 16 bits:
52  // 0000 xxxx xxxx xxxx)
53  // ---------------------------------------------------------------------
54 
55  // Note that all values are in motorola (big-endian) format, and that long is
56  // assumed to be 4 bytes, and short 2 bytes.
57  // When reading the samples, you should handle both signed and unsigned data,
58  // and be prepared to convert 16->8 bit, or mono->stereo if needed. To convert
59  // 8-bit data between signed/unsigned just add 127 to the sample values.
60  // Simularly for 16-bit data you should add 32769
61 
62  $ThisFileInfo['fileformat'] = 'avr';
63 
64  fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
65  $AVRheader = fread($fd, 128);
66 
67  $ThisFileInfo['avr']['raw']['magic'] = substr($AVRheader, 0, 4);
68  if ($ThisFileInfo['avr']['raw']['magic'] != '2BIT') {
69  $ThisFileInfo['error'][] = 'Expecting "2BIT" at offset '.$ThisFileInfo['avdataoffset'].', found "'.$ThisFileInfo['avr']['raw']['magic'].'"';
70  unset($ThisFileInfo['fileformat']);
71  unset($ThisFileInfo['avr']);
72  return false;
73  }
74  $ThisFileInfo['avdataoffset'] += 128;
75 
76  $ThisFileInfo['avr']['sample_name'] = rtrim(substr($AVRheader, 4, 8));
77  $ThisFileInfo['avr']['raw']['mono'] = getid3_lib::BigEndian2Int(substr($AVRheader, 12, 2));
78  $ThisFileInfo['avr']['bits_per_sample'] = getid3_lib::BigEndian2Int(substr($AVRheader, 14, 2));
79  $ThisFileInfo['avr']['raw']['signed'] = getid3_lib::BigEndian2Int(substr($AVRheader, 16, 2));
80  $ThisFileInfo['avr']['raw']['loop'] = getid3_lib::BigEndian2Int(substr($AVRheader, 18, 2));
81  $ThisFileInfo['avr']['raw']['midi'] = getid3_lib::BigEndian2Int(substr($AVRheader, 20, 2));
82  $ThisFileInfo['avr']['raw']['replay_freq'] = getid3_lib::BigEndian2Int(substr($AVRheader, 22, 1));
83  $ThisFileInfo['avr']['sample_rate'] = getid3_lib::BigEndian2Int(substr($AVRheader, 23, 3));
84  $ThisFileInfo['avr']['sample_length'] = getid3_lib::BigEndian2Int(substr($AVRheader, 26, 4));
85  $ThisFileInfo['avr']['loop_start'] = getid3_lib::BigEndian2Int(substr($AVRheader, 30, 4));
86  $ThisFileInfo['avr']['loop_end'] = getid3_lib::BigEndian2Int(substr($AVRheader, 34, 4));
87  $ThisFileInfo['avr']['midi_split'] = getid3_lib::BigEndian2Int(substr($AVRheader, 38, 2));
88  $ThisFileInfo['avr']['sample_compression'] = getid3_lib::BigEndian2Int(substr($AVRheader, 40, 2));
89  $ThisFileInfo['avr']['reserved'] = getid3_lib::BigEndian2Int(substr($AVRheader, 42, 2));
90  $ThisFileInfo['avr']['sample_name_extra'] = rtrim(substr($AVRheader, 44, 20));
91  $ThisFileInfo['avr']['comment'] = rtrim(substr($AVRheader, 64, 64));
92 
93  $ThisFileInfo['avr']['flags']['stereo'] = (($ThisFileInfo['avr']['raw']['mono'] == 0) ? false : true);
94  $ThisFileInfo['avr']['flags']['signed'] = (($ThisFileInfo['avr']['raw']['signed'] == 0) ? false : true);
95  $ThisFileInfo['avr']['flags']['loop'] = (($ThisFileInfo['avr']['raw']['loop'] == 0) ? false : true);
96 
97  $ThisFileInfo['avr']['midi_notes'] = array();
98  if (($ThisFileInfo['avr']['raw']['midi'] & 0xFF00) != 0xFF00) {
99  $ThisFileInfo['avr']['midi_notes'][] = ($ThisFileInfo['avr']['raw']['midi'] & 0xFF00) >> 8;
100  }
101  if (($ThisFileInfo['avr']['raw']['midi'] & 0x00FF) != 0x00FF) {
102  $ThisFileInfo['avr']['midi_notes'][] = ($ThisFileInfo['avr']['raw']['midi'] & 0x00FF);
103  }
104 
105  if (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) != ($ThisFileInfo['avr']['sample_length'] * (($ThisFileInfo['avr']['bits_per_sample'] == 8) ? 1 : 2))) {
106  $ThisFileInfo['warning'][] = 'Probable truncated file: expecting '.($ThisFileInfo['avr']['sample_length'] * (($ThisFileInfo['avr']['bits_per_sample'] == 8) ? 1 : 2)).' bytes of audio data, found '.($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']);
107  }
108 
109  $ThisFileInfo['audio']['dataformat'] = 'avr';
110  $ThisFileInfo['audio']['lossless'] = true;
111  $ThisFileInfo['audio']['bitrate_mode'] = 'cbr';
112  $ThisFileInfo['audio']['bits_per_sample'] = $ThisFileInfo['avr']['bits_per_sample'];
113  $ThisFileInfo['audio']['sample_rate'] = $ThisFileInfo['avr']['sample_rate'];
114  $ThisFileInfo['audio']['channels'] = ($ThisFileInfo['avr']['flags']['stereo'] ? 2 : 1);
115  $ThisFileInfo['playtime_seconds'] = ($ThisFileInfo['avr']['sample_length'] / $ThisFileInfo['audio']['channels']) / $ThisFileInfo['avr']['sample_rate'];
116  $ThisFileInfo['audio']['bitrate'] = ($ThisFileInfo['avr']['sample_length'] * (($ThisFileInfo['avr']['bits_per_sample'] == 8) ? 8 : 16)) / $ThisFileInfo['playtime_seconds'];
117 
118 
119  return true;
120  }
121 
122 }
123 
124 
125 ?>