Location: PHPKode > projects > Multimedia Files Scanner > getid3/getid3.la.php
<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <hide@address.com>               //
//  available at http://getid3.sourceforge.net                ///
//            or http://www.getid3.org                        ///
/////////////////////////////////////////////////////////////////
//                                                             //
// getid3.la.php - part of getID3()                            //
// See getid3.readme.txt for more details                      //
//                                                             //
/////////////////////////////////////////////////////////////////

function getLAHeaderFilepointer(&$fd, &$ThisFileInfo) {
	$offset = 0;
	fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
	$rawdata = fread($fd, FREAD_BUFFER_SIZE);

	switch (substr($rawdata, $offset, 4)) {
		case 'LA02':
		case 'LA03':
		case 'LA04':
			$ThisFileInfo['fileformat']          = 'la';
			$ThisFileInfo['audio']['dataformat'] = 'la';
			$ThisFileInfo['audio']['lossless']   = true;

			$ThisFileInfo['la']['version_major'] = (int) substr($rawdata, $offset + 2, 1);
			$ThisFileInfo['la']['version_minor'] = (int) substr($rawdata, $offset + 3, 1);
			$ThisFileInfo['la']['version']       = (float) $ThisFileInfo['la']['version_major'] + ($ThisFileInfo['la']['version_minor'] / 10);
			$offset += 4;

			$ThisFileInfo['la']['uncompressed_size'] = LittleEndian2Int(substr($rawdata, $offset, 4));
			$offset += 4;
			if ($ThisFileInfo['la']['uncompressed_size'] == 0) {
				$ThisFileInfo['error'] .= "\n".'Corrupt LA file: uncompressed_size == zero';
				return false;
			}

			$WAVEchunk = substr($rawdata, $offset, 4);
			if ($WAVEchunk !== 'WAVE') {
				$ThisFileInfo['error'] .= "\n".'Expected "WAVE" ('.PrintHexBytes('WAVE').') at offset '.$offset.', found "'.$WAVEchunk.'" ('.PrintHexBytes($WAVEchunk).') instead.';
				return false;
			}
			$offset += 4;

			$ThisFileInfo['la']['format_size']          = 24;
			if ($ThisFileInfo['la']['version'] >= 0.3) {

				$ThisFileInfo['la']['format_size']      = LittleEndian2Int(substr($rawdata, $offset, 4));
				$ThisFileInfo['la']['header_size']      = 49 + $ThisFileInfo['la']['format_size'] - 24;
				$offset += 4;

			} else {

				// version 0.2 didn't support additional data blocks
				$ThisFileInfo['la']['header_size']      = 41;

			}

			$fmt_chunk = substr($rawdata, $offset, 4);
			if ($fmt_chunk !== 'fmt ') {
				$ThisFileInfo['error'] .= "\n".'Expected "fmt " ('.PrintHexBytes('fmt ').') at offset '.$offset.', found "'.$fmt_chunk.'" ('.PrintHexBytes($fmt_chunk).') instead.';
				return false;
			}
			$offset += 4;
			$fmt_size = LittleEndian2Int(substr($rawdata, $offset, 4));
			$offset += 4;

			$ThisFileInfo['la']['format_raw']           = LittleEndian2Int(substr($rawdata, $offset, 2));
			$offset += 2;

			$ThisFileInfo['la']['channels']             = LittleEndian2Int(substr($rawdata, $offset, 2));
			$offset += 2;
			if ($ThisFileInfo['la']['channels'] == 0) {
				$ThisFileInfo['error'] .= "\n".'Corrupt LA file: channels == zero';
					return false;
			}

			$ThisFileInfo['la']['sample_rate']          = LittleEndian2Int(substr($rawdata, $offset, 4));
			$offset += 4;
			if ($ThisFileInfo['la']['sample_rate'] == 0) {
				$ThisFileInfo['error'] .= "\n".'Corrupt LA file: sample_rate == zero';
					return false;
			}

			$ThisFileInfo['la']['bytes_per_second']     = LittleEndian2Int(substr($rawdata, $offset, 4));
			$offset += 4;
			$ThisFileInfo['la']['bytes_per_sample']     = LittleEndian2Int(substr($rawdata, $offset, 2));
			$offset += 2;
			$ThisFileInfo['la']['bits_per_sample']      = LittleEndian2Int(substr($rawdata, $offset, 2));
			$offset += 2;

			$ThisFileInfo['la']['samples']              = LittleEndian2Int(substr($rawdata, $offset, 4));
			$offset += 4;

			$LaHeaderFlags                              = LittleEndian2Int(substr($rawdata, $offset, 1));
			$offset += 1;
			$ThisFileInfo['la']['seekable']             = (bool) ($LaHeaderFlags & 0x01);
			if ($ThisFileInfo['la']['version'] >= 0.4) {
				$ThisFileInfo['la']['high_compression'] = (bool) ($LaHeaderFlags & 0x02);
			}

			$ThisFileInfo['la']['original_crc']         = LittleEndian2Int(substr($rawdata, $offset, 4));
			$offset += 4;

			require_once(GETID3_INCLUDEPATH.'getid3.riff.php');
			$ThisFileInfo['la']['codec']                = RIFFwFormatTagLookup($ThisFileInfo['la']['format_raw']);
			$ThisFileInfo['la']['compression_ratio']    = (float) (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) / $ThisFileInfo['la']['uncompressed_size']);
			$ThisFileInfo['playtime_seconds']           = (float) ($ThisFileInfo['la']['samples'] / $ThisFileInfo['la']['sample_rate']) / $ThisFileInfo['la']['channels'];
			if ($ThisFileInfo['playtime_seconds'] == 0) {
				$ThisFileInfo['error'] .= "\n".'Corrupt LA file: playtime_seconds == zero';
				return false;
			}

			// add size of file header to avdataoffset - calc bitrate correctly + MD5 data
			$ThisFileInfo['avdataoffset'] += $ThisFileInfo['la']['header_size'];

			$ThisFileInfo['audio']['bitrate']            = ($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8 / $ThisFileInfo['playtime_seconds'];
			$ThisFileInfo['audio']['codec']              = $ThisFileInfo['la']['codec'];
			$ThisFileInfo['audio']['bits_per_sample']    = $ThisFileInfo['la']['bits_per_sample'];
			break;

		default:
			if (substr($rawdata, $offset, 2) == 'LA') {
				$ThisFileInfo['error'] .= "\n".'This version of getID3() (v'.GETID3VERSION.') doesn\'t support LA version '.substr($rawdata, $offset + 2, 1).'.'.substr($rawdata, $offset + 3, 1).' which this appears to be - check http://getid3.sourceforge.net for updates.';
			} else {
				$ThisFileInfo['error'] .= "\n".'Not a LA (Lossless-Audio) file';
			}
			return false;
			break;
	}

	$ThisFileInfo['audio']['channels']    = $ThisFileInfo['la']['channels'];
	$ThisFileInfo['audio']['sample_rate'] = (int) $ThisFileInfo['la']['sample_rate'];
	$ThisFileInfo['audio']['encoder']     = 'LA v'.$ThisFileInfo['la']['version'];

	return true;
}

?>
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