rlm@3: <?php
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | PHP version 5                                                        |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen                 |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | This source file is subject to version 2 of the GPL license,         |
rlm@3: // | that is bundled with this package in the file license.txt and is     |
rlm@3: // | available through the world-wide-web at the following url:           |
rlm@3: // | http://www.gnu.org/copyleft/gpl.html                                 |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org    |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | Authors: James Heinrich <infoØgetid3*org>                            |
rlm@3: // |          Allan Hansen <ahØartemis*dk>                                |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: // | module.audio.lpac.php                                                |
rlm@3: // | Module for analyzing LPAC Audio files                                |
rlm@3: // | dependencies: module.audio-video.riff.php                            |
rlm@3: // +----------------------------------------------------------------------+
rlm@3: //
rlm@3: // $Id: module.audio.lpac.php,v 1.2 2006/11/02 10:48:01 ah Exp $
rlm@3: 
rlm@3:         
rlm@3:         
rlm@3: class getid3_lpac extends getid3_handler
rlm@3: {
rlm@3: 
rlm@3:     public function Analyze() {
rlm@3:         
rlm@3:         $getid3 = $this->getid3;
rlm@3:         
rlm@3:         $getid3->include_module('audio-video.riff');
rlm@3:         
rlm@3:         // Magic bytes - 'LPAC'
rlm@3:         
rlm@3:         fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);
rlm@3:         $lpac_header = fread($getid3->fp, 14);
rlm@3:         
rlm@3:         $getid3->info['avdataoffset'] += 14;
rlm@3:         
rlm@3:         $getid3->info['lpac'] = array ();
rlm@3:         $info_lpac = &$getid3->info['lpac'];
rlm@3: 
rlm@3:         $getid3->info['fileformat']               = 'lpac';
rlm@3:         $getid3->info['audio']['dataformat']      = 'lpac';
rlm@3:         $getid3->info['audio']['lossless']        = true;
rlm@3:         $getid3->info['audio']['bitrate_mode']    = 'vbr';
rlm@3:                                                   
rlm@3:         $info_lpac['file_version']     = getid3_lib::BigEndian2Int($lpac_header{4});
rlm@3:         $flags['audio_type']                      = getid3_lib::BigEndian2Int($lpac_header{5});
rlm@3:         $info_lpac['total_samples']    = getid3_lib::BigEndian2Int(substr($lpac_header,  6, 4));
rlm@3:         $flags['parameters']                      = getid3_lib::BigEndian2Int(substr($lpac_header, 10, 4));
rlm@3: 
rlm@3:         $info_lpac['flags']['is_wave'] = (bool)($flags['audio_type'] & 0x40);
rlm@3:         $info_lpac['flags']['stereo']  = (bool)($flags['audio_type'] & 0x04);
rlm@3:         $info_lpac['flags']['24_bit']  = (bool)($flags['audio_type'] & 0x02);
rlm@3:         $info_lpac['flags']['16_bit']  = (bool)($flags['audio_type'] & 0x01);
rlm@3: 
rlm@3:         if ($info_lpac['flags']['24_bit'] && $info_lpac['flags']['16_bit']) {
rlm@3:             $getid3->warning('24-bit and 16-bit flags cannot both be set');
rlm@3:         }
rlm@3: 
rlm@3:         $info_lpac['flags']['fast_compress']             =   (bool)($flags['parameters'] & 0x40000000);
rlm@3:         $info_lpac['flags']['random_access']             =   (bool)($flags['parameters'] & 0x08000000);
rlm@3:         $info_lpac['block_length']                       = pow(2, (($flags['parameters'] & 0x07000000) >> 24)) * 256;
rlm@3:         $info_lpac['flags']['adaptive_prediction_order'] =   (bool)($flags['parameters'] & 0x00800000);
rlm@3:         $info_lpac['flags']['adaptive_quantization']     =   (bool)($flags['parameters'] & 0x00400000);
rlm@3:         $info_lpac['flags']['joint_stereo']              =   (bool)($flags['parameters'] & 0x00040000);
rlm@3:         $info_lpac['quantization']                       =         ($flags['parameters'] & 0x00001F00) >> 8;
rlm@3:         $info_lpac['max_prediction_order']               =         ($flags['parameters'] & 0x0000003F);
rlm@3: 
rlm@3:         if ($info_lpac['flags']['fast_compress'] && ($info_lpac['max_prediction_order'] != 3)) {
rlm@3:             $getid3->warning('max_prediction_order expected to be "3" if fast_compress is true, actual value is "'.$info_lpac['max_prediction_order'].'"');
rlm@3:         }
rlm@3:         
rlm@3:         switch ($info_lpac['file_version']) {
rlm@3:         
rlm@3:             case 6:
rlm@3:                 if ($info_lpac['flags']['adaptive_quantization']) {
rlm@3:                     $getid3->warning('adaptive_quantization expected to be false in LPAC file stucture v6, actually true');
rlm@3:                 }
rlm@3:                 if ($info_lpac['quantization'] != 20) {
rlm@3:                     $getid3->warning('Quantization expected to be 20 in LPAC file stucture v6, actually '.$info_lpac['flags']['Q']);
rlm@3:                 }
rlm@3:                 break;
rlm@3: 
rlm@3:         
rlm@3:             default:
rlm@3:                 //$getid3->warning('This version of getID3() only supports LPAC file format version 6, this file is version '.$info_lpac['file_version'].' - please report to info@getid3.org');
rlm@3:                 break;
rlm@3:         }
rlm@3: 
rlm@3:         // Clone getid3 - messing with something - better safe than sorry
rlm@3:         $clone = clone $getid3;
rlm@3:         
rlm@3:         // Analyze clone by fp
rlm@3:         $riff = new getid3_riff($clone);
rlm@3:         $riff->Analyze();
rlm@3:         
rlm@3:         // Import from clone and destroy
rlm@3:         $getid3->info['avdataoffset']                = $clone->info['avdataoffset'];
rlm@3:         $getid3->info['riff']                        = $clone->info['riff'];
rlm@3:         //$info_lpac['comments']['comment'] = $clone->info['comments'];
rlm@3:         $getid3->info['audio']['sample_rate']        = $clone->info['audio']['sample_rate'];
rlm@3:         $getid3->warnings($clone->warnings());
rlm@3:         unset($clone);
rlm@3:         
rlm@3:         $getid3->info['audio']['channels'] = ($info_lpac['flags']['stereo'] ? 2 : 1);
rlm@3: 
rlm@3:         if ($info_lpac['flags']['24_bit']) {
rlm@3:             $getid3->info['audio']['bits_per_sample'] = $getid3->info['riff']['audio'][0]['bits_per_sample'];
rlm@3:         } elseif ($info_lpac['flags']['16_bit']) {
rlm@3:             $getid3->info['audio']['bits_per_sample'] = 16;
rlm@3:         } else {
rlm@3:             $getid3->info['audio']['bits_per_sample'] = 8;
rlm@3:         }
rlm@3: 
rlm@3:         if ($info_lpac['flags']['fast_compress']) {
rlm@3:              // fast
rlm@3:             $getid3->info['audio']['encoder_options'] = '-1';
rlm@3:         } else {
rlm@3:             switch ($info_lpac['max_prediction_order']) {
rlm@3:                 case 20: // simple
rlm@3:                     $getid3->info['audio']['encoder_options'] = '-2';
rlm@3:                     break;
rlm@3:                 case 30: // medium
rlm@3:                     $getid3->info['audio']['encoder_options'] = '-3';
rlm@3:                     break;
rlm@3:                 case 40: // high
rlm@3:                     $getid3->info['audio']['encoder_options'] = '-4';
rlm@3:                     break;
rlm@3:                 case 60: // extrahigh
rlm@3:                     $getid3->info['audio']['encoder_options'] = '-5';
rlm@3:                     break;
rlm@3:             }
rlm@3:         }
rlm@3: 
rlm@3:         $getid3->info['playtime_seconds'] = $info_lpac['total_samples'] / $getid3->info['audio']['sample_rate'];
rlm@3:         $getid3->info['audio']['bitrate'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / $getid3->info['playtime_seconds'];
rlm@3: 
rlm@3:         return true;
rlm@3:     }
rlm@3: 
rlm@3: }
rlm@3: 
rlm@3: 
rlm@3: ?>