getID3() by James Heinrich <info@getid3.org> // More...
Public Member Functions | |
| getid3_avr (&$fd, &$ThisFileInfo) | |
Detailed Description
getID3() by James Heinrich <info@getid3.org> //
Definition at line 17 of file module.audio.avr.php.
Member Function Documentation
| getid3_avr::getid3_avr | ( | &$ | fd, | |
| &$ | ThisFileInfo | |||
| ) |
Definition at line 20 of file module.audio.avr.php.
References getid3_lib::BigEndian2Int().
{
// http://cui.unige.ch/OSG/info/AudioFormats/ap11.html
// http://www.btinternet.com/~AnthonyJ/Atari/programming/avr_format.html
// offset type length name comments
// ---------------------------------------------------------------------
// 0 char 4 ID format ID == "2BIT"
// 4 char 8 name sample name (unused space filled with 0)
// 12 short 1 mono/stereo 0=mono, -1 (0xFFFF)=stereo
// With stereo, samples are alternated,
// the first voice is the left :
// (LRLRLRLRLRLRLRLRLR...)
// 14 short 1 resolution 8, 12 or 16 (bits)
// 16 short 1 signed or not 0=unsigned, -1 (0xFFFF)=signed
// 18 short 1 loop or not 0=no loop, -1 (0xFFFF)=loop on
// 20 short 1 MIDI note 0xFFnn, where 0 <= nn <= 127
// 0xFFFF means "no MIDI note defined"
// 22 byte 1 Replay speed Frequence in the Replay software
// 0=5.485 Khz, 1=8.084 Khz, 2=10.971 Khz,
// 3=16.168 Khz, 4=21.942 Khz, 5=32.336 Khz
// 6=43.885 Khz, 7=47.261 Khz
// -1 (0xFF)=no defined Frequence
// 23 byte 3 sample rate in Hertz
// 26 long 1 size in bytes (2 * bytes in stereo)
// 30 long 1 loop begin 0 for no loop
// 34 long 1 loop size equal to 'size' for no loop
// 38 short 2 Reserved, MIDI keyboard split */
// 40 short 2 Reserved, sample compression */
// 42 short 2 Reserved */
// 44 char 20; Additional filename space, used if (name[7] != 0)
// 64 byte 64 user data
// 128 bytes ? sample data (12 bits samples are coded on 16 bits:
// 0000 xxxx xxxx xxxx)
// ---------------------------------------------------------------------
// Note that all values are in motorola (big-endian) format, and that long is
// assumed to be 4 bytes, and short 2 bytes.
// When reading the samples, you should handle both signed and unsigned data,
// and be prepared to convert 16->8 bit, or mono->stereo if needed. To convert
// 8-bit data between signed/unsigned just add 127 to the sample values.
// Simularly for 16-bit data you should add 32769
$ThisFileInfo['fileformat'] = 'avr';
fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
$AVRheader = fread($fd, 128);
$ThisFileInfo['avr']['raw']['magic'] = substr($AVRheader, 0, 4);
if ($ThisFileInfo['avr']['raw']['magic'] != '2BIT') {
$ThisFileInfo['error'][] = 'Expecting "2BIT" at offset '.$ThisFileInfo['avdataoffset'].', found "'.$ThisFileInfo['avr']['raw']['magic'].'"';
unset($ThisFileInfo['fileformat']);
unset($ThisFileInfo['avr']);
return false;
}
$ThisFileInfo['avdataoffset'] += 128;
$ThisFileInfo['avr']['sample_name'] = rtrim(substr($AVRheader, 4, 8));
$ThisFileInfo['avr']['raw']['mono'] = getid3_lib::BigEndian2Int(substr($AVRheader, 12, 2));
$ThisFileInfo['avr']['bits_per_sample'] = getid3_lib::BigEndian2Int(substr($AVRheader, 14, 2));
$ThisFileInfo['avr']['raw']['signed'] = getid3_lib::BigEndian2Int(substr($AVRheader, 16, 2));
$ThisFileInfo['avr']['raw']['loop'] = getid3_lib::BigEndian2Int(substr($AVRheader, 18, 2));
$ThisFileInfo['avr']['raw']['midi'] = getid3_lib::BigEndian2Int(substr($AVRheader, 20, 2));
$ThisFileInfo['avr']['raw']['replay_freq'] = getid3_lib::BigEndian2Int(substr($AVRheader, 22, 1));
$ThisFileInfo['avr']['sample_rate'] = getid3_lib::BigEndian2Int(substr($AVRheader, 23, 3));
$ThisFileInfo['avr']['sample_length'] = getid3_lib::BigEndian2Int(substr($AVRheader, 26, 4));
$ThisFileInfo['avr']['loop_start'] = getid3_lib::BigEndian2Int(substr($AVRheader, 30, 4));
$ThisFileInfo['avr']['loop_end'] = getid3_lib::BigEndian2Int(substr($AVRheader, 34, 4));
$ThisFileInfo['avr']['midi_split'] = getid3_lib::BigEndian2Int(substr($AVRheader, 38, 2));
$ThisFileInfo['avr']['sample_compression'] = getid3_lib::BigEndian2Int(substr($AVRheader, 40, 2));
$ThisFileInfo['avr']['reserved'] = getid3_lib::BigEndian2Int(substr($AVRheader, 42, 2));
$ThisFileInfo['avr']['sample_name_extra'] = rtrim(substr($AVRheader, 44, 20));
$ThisFileInfo['avr']['comment'] = rtrim(substr($AVRheader, 64, 64));
$ThisFileInfo['avr']['flags']['stereo'] = (($ThisFileInfo['avr']['raw']['mono'] == 0) ? false : true);
$ThisFileInfo['avr']['flags']['signed'] = (($ThisFileInfo['avr']['raw']['signed'] == 0) ? false : true);
$ThisFileInfo['avr']['flags']['loop'] = (($ThisFileInfo['avr']['raw']['loop'] == 0) ? false : true);
$ThisFileInfo['avr']['midi_notes'] = array();
if (($ThisFileInfo['avr']['raw']['midi'] & 0xFF00) != 0xFF00) {
$ThisFileInfo['avr']['midi_notes'][] = ($ThisFileInfo['avr']['raw']['midi'] & 0xFF00) >> 8;
}
if (($ThisFileInfo['avr']['raw']['midi'] & 0x00FF) != 0x00FF) {
$ThisFileInfo['avr']['midi_notes'][] = ($ThisFileInfo['avr']['raw']['midi'] & 0x00FF);
}
if (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) != ($ThisFileInfo['avr']['sample_length'] * (($ThisFileInfo['avr']['bits_per_sample'] == 8) ? 1 : 2))) {
$ThisFileInfo['warning'][] = 'Probable truncated file: expecting '.($ThisFileInfo['avr']['sample_length'] * (($ThisFileInfo['avr']['bits_per_sample'] == 8) ? 1 : 2)).' bytes of audio data, found '.($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']);
}
$ThisFileInfo['audio']['dataformat'] = 'avr';
$ThisFileInfo['audio']['lossless'] = true;
$ThisFileInfo['audio']['bitrate_mode'] = 'cbr';
$ThisFileInfo['audio']['bits_per_sample'] = $ThisFileInfo['avr']['bits_per_sample'];
$ThisFileInfo['audio']['sample_rate'] = $ThisFileInfo['avr']['sample_rate'];
$ThisFileInfo['audio']['channels'] = ($ThisFileInfo['avr']['flags']['stereo'] ? 2 : 1);
$ThisFileInfo['playtime_seconds'] = ($ThisFileInfo['avr']['sample_length'] / $ThisFileInfo['audio']['channels']) / $ThisFileInfo['avr']['sample_rate'];
$ThisFileInfo['audio']['bitrate'] = ($ThisFileInfo['avr']['sample_length'] * (($ThisFileInfo['avr']['bits_per_sample'] == 8) ? 8 : 16)) / $ThisFileInfo['playtime_seconds'];
return true;
}
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The documentation for this class was generated from the following file:
- Services/MediaObjects/getid3/getid3/module.audio.avr.php
