getid3_avr Class Reference
getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g // More...
Collaboration diagram for getid3_avr:
Public Member Functions | |
| getid3_avr (&$fd, &$ThisFileInfo) | |
Detailed Description
getID3() by James Heinrich info@.nosp@m.geti.nosp@m.d3.or.nosp@m.g //
Definition at line 17 of file module.audio.avr.php.
Member Function Documentation
◆ getid3_avr()
| getid3_avr::getid3_avr | ( | & | $fd, |
| & | $ThisFileInfo | ||
| ) |
Definition at line 20 of file module.audio.avr.php.
20 {
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));
82 $ThisFileInfo['avr']['raw']['replay_freq'] = getid3_lib::BigEndian2Int(substr($AVRheader, 22, 1));
88 $ThisFileInfo['avr']['sample_compression'] = getid3_lib::BigEndian2Int(substr($AVRheader, 40, 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)) / $ThisFileInfo['playtime_seconds'];
117
118
119 return true;
120 }
BigEndian2Int($byteword, $synchsafe=false, $signed=false)
Definition: getid3.lib.php:234
References getid3_lib\BigEndian2Int().
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The documentation for this class was generated from the following file:
- Services/MediaObjects/getid3/getid3/module.audio.avr.php
