mirror of
https://github.com/Yetangitu/ampache
synced 2025-10-05 02:39:47 +02:00
107 lines
No EOL
5.2 KiB
PHP
107 lines
No EOL
5.2 KiB
PHP
<?php
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// +----------------------------------------------------------------------+
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// | PHP version 5 |
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// +----------------------------------------------------------------------+
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// | Copyright (c) 2002-2006 James Heinrich, Allan Hansen |
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// +----------------------------------------------------------------------+
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// | This source file is subject to version 2 of the GPL license, |
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// | that is bundled with this package in the file license.txt and is |
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// | available through the world-wide-web at the following url: |
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// | http://www.gnu.org/copyleft/gpl.html |
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// +----------------------------------------------------------------------+
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// | getID3() - http://getid3.sourceforge.net or http://www.getid3.org |
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// +----------------------------------------------------------------------+
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// | Authors: James Heinrich <infoØgetid3*org> |
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// | Allan Hansen <ahØartemis*dk> |
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// +----------------------------------------------------------------------+
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// | module.audio.mpc_old.php |
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// | Module for analyzing Musepack/MPEG+ Audio files - SV4-SV6 |
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// | dependencies: NONE |
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// +----------------------------------------------------------------------+
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//
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// $Id: module.audio.mpc_old.php,v 1.2 2006/11/02 10:48:01 ah Exp $
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class getid3_mpc_old extends getid3_handler
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{
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public function Analyze() {
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$getid3 = $this->getid3;
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// http://www.uni-jena.de/~pfk/mpp/sv8/header.html
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$getid3->info['mpc']['header'] = array ();
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$info_mpc_header = &$getid3->info['mpc']['header'];
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$getid3->info['fileformat'] = 'mpc';
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$getid3->info['audio']['dataformat'] = 'mpc';
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$getid3->info['audio']['bitrate_mode'] = 'vbr';
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$getid3->info['audio']['channels'] = 2; // the format appears to be hardcoded for stereo only
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$getid3->info['audio']['lossless'] = false;
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fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);
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$info_mpc_header['size'] = 8;
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$getid3->info['avdataoffset'] += $info_mpc_header['size'];
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$mpc_header_data = fread($getid3->fp, $info_mpc_header['size']);
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// Most of this code adapted from Jurgen Faul's MPEGplus source code - thanks Jurgen! :)
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$header_dword[0] = getid3_lib::LittleEndian2Int(substr($mpc_header_data, 0, 4));
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$header_dword[1] = getid3_lib::LittleEndian2Int(substr($mpc_header_data, 4, 4));
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// DDDD DDDD CCCC CCCC BBBB BBBB AAAA AAAA
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// aaaa aaaa abcd dddd dddd deee eeff ffff
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//
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// a = bitrate = anything
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// b = IS = anything
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// c = MS = anything
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// d = streamversion = 0000000004 or 0000000005 or 0000000006
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// e = maxband = anything
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// f = blocksize = 000001 for SV5+, anything(?) for SV4
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$info_mpc_header['target_bitrate'] = (($header_dword[0] & 0xFF800000) >> 23);
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$info_mpc_header['intensity_stereo'] = (bool)(($header_dword[0] & 0x00400000) >> 22);
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$info_mpc_header['mid-side_stereo'] = (bool)(($header_dword[0] & 0x00200000) >> 21);
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$info_mpc_header['stream_major_version'] = ($header_dword[0] & 0x001FF800) >> 11;
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$info_mpc_header['stream_minor_version'] = 0;
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$info_mpc_header['max_band'] = ($header_dword[0] & 0x000007C0) >> 6; // related to lowpass frequency, not sure how it translates exactly
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$info_mpc_header['block_size'] = ($header_dword[0] & 0x0000003F);
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switch ($info_mpc_header['stream_major_version']) {
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case 4:
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$info_mpc_header['frame_count'] = ($header_dword[1] >> 16);
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break;
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case 5:
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case 6:
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$info_mpc_header['frame_count'] = $header_dword[1];
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break;
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default:
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throw new getid3_exception('Expecting 4, 5 or 6 in version field, found '.$info_mpc_header['stream_major_version'].' instead');
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}
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if (($info_mpc_header['stream_major_version'] > 4) && ($info_mpc_header['block_size'] != 1)) {
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$getid3->warning('Block size expected to be 1, actual value found: '.$info_mpc_header['block_size']);
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}
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$info_mpc_header['sample_rate'] = $getid3->info['audio']['sample_rate'] = 44100; // AB: used by all files up to SV7
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$info_mpc_header['samples'] = $info_mpc_header['frame_count'] * 1152 * $getid3->info['audio']['channels'];
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$getid3->info['audio']['bitrate_mode'] = $info_mpc_header['target_bitrate'] == 0 ? 'vbr' : 'cbr';
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$getid3->info['mpc']['bitrate'] = ($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8 * 44100 / $info_mpc_header['frame_count'] / 1152;
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$getid3->info['audio']['bitrate'] = $getid3->info['mpc']['bitrate'];
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$getid3->info['audio']['encoder'] = 'SV'.$info_mpc_header['stream_major_version'];
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return true;
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}
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}
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?>
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