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File: includes/getid3/module.audio.lpac.php

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  Classes of Karl Holz  >  WaldScan  >  includes/getid3/module.audio.lpac.php  >  Download  
File: includes/getid3/module.audio.lpac.php
Role: Auxiliary script
Content type: text/plain
Description: getID3 dependency
Class: WaldScan
Scan directories for files with certain extensions
Author: By
Last change:
Date: 1 year ago
Size: 5,884 bytes
 

Contents

Class file image Download
<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org> //
// available at http://getid3.sourceforge.net //
// or http://www.getid3.org //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details //
/////////////////////////////////////////////////////////////////
// //
// module.audio.lpac.php //
// module for analyzing LPAC Audio files //
// dependencies: module.audio-video.riff.php //
// ///
/////////////////////////////////////////////////////////////////

getid3_lib::IncludeDependency(GETID3_INCLUDEPATH.'module.audio-video.riff.php', __FILE__, true);

class
getid3_lpac extends getid3_handler
{

    function
Analyze() {
       
$info = &$this->getid3->info;

       
fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
       
$LPACheader = fread($this->getid3->fp, 14);
        if (
substr($LPACheader, 0, 4) != 'LPAC') {
           
$info['error'][] = 'Expected "LPAC" at offset '.$info['avdataoffset'].', found "'.$StreamMarker.'"';
            return
false;
        }
       
$info['avdataoffset'] += 14;

       
$info['fileformat'] = 'lpac';
       
$info['audio']['dataformat'] = 'lpac';
       
$info['audio']['lossless'] = true;
       
$info['audio']['bitrate_mode'] = 'vbr';

       
$info['lpac']['file_version'] = getid3_lib::BigEndian2Int(substr($LPACheader, 4, 1));
       
$flags['audio_type'] = getid3_lib::BigEndian2Int(substr($LPACheader, 5, 1));
       
$info['lpac']['total_samples']= getid3_lib::BigEndian2Int(substr($LPACheader, 6, 4));
       
$flags['parameters'] = getid3_lib::BigEndian2Int(substr($LPACheader, 10, 4));

       
$info['lpac']['flags']['is_wave'] = (bool) ($flags['audio_type'] & 0x40);
       
$info['lpac']['flags']['stereo'] = (bool) ($flags['audio_type'] & 0x04);
       
$info['lpac']['flags']['24_bit'] = (bool) ($flags['audio_type'] & 0x02);
       
$info['lpac']['flags']['16_bit'] = (bool) ($flags['audio_type'] & 0x01);

        if (
$info['lpac']['flags']['24_bit'] && $info['lpac']['flags']['16_bit']) {
           
$info['warning'][] = '24-bit and 16-bit flags cannot both be set';
        }

       
$info['lpac']['flags']['fast_compress'] = (bool) ($flags['parameters'] & 0x40000000);
       
$info['lpac']['flags']['random_access'] = (bool) ($flags['parameters'] & 0x08000000);
       
$info['lpac']['block_length'] = pow(2, (($flags['parameters'] & 0x07000000) >> 24)) * 256;
       
$info['lpac']['flags']['adaptive_prediction_order'] = (bool) ($flags['parameters'] & 0x00800000);
       
$info['lpac']['flags']['adaptive_quantization'] = (bool) ($flags['parameters'] & 0x00400000);
       
$info['lpac']['flags']['joint_stereo'] = (bool) ($flags['parameters'] & 0x00040000);
       
$info['lpac']['quantization'] = ($flags['parameters'] & 0x00001F00) >> 8;
       
$info['lpac']['max_prediction_order'] = ($flags['parameters'] & 0x0000003F);

        if (
$info['lpac']['flags']['fast_compress'] && ($info['lpac']['max_prediction_order'] != 3)) {
           
$info['warning'][] = 'max_prediction_order expected to be "3" if fast_compress is true, actual value is "'.$info['lpac']['max_prediction_order'].'"';
        }
        switch (
$info['lpac']['file_version']) {
            case
6:
                if (
$info['lpac']['flags']['adaptive_quantization']) {
                   
$info['warning'][] = 'adaptive_quantization expected to be false in LPAC file stucture v6, actually true';
                }
                if (
$info['lpac']['quantization'] != 20) {
                   
$info['warning'][] = 'Quantization expected to be 20 in LPAC file stucture v6, actually '.$info['lpac']['flags']['Q'];
                }
                break;

            default:
               
//$info['warning'][] = 'This version of getID3() ['.$this->getid3->version().'] only supports LPAC file format version 6, this file is version '.$info['lpac']['file_version'].' - please report to info@getid3.org';
               
break;
        }

       
$getid3_temp = new getID3();
       
$getid3_temp->openfile($this->getid3->filename);
       
$getid3_temp->info = $info;
       
$getid3_riff = new getid3_riff($getid3_temp);
       
$getid3_riff->Analyze();
       
$info['avdataoffset'] = $getid3_temp->info['avdataoffset'];
       
$info['riff'] = $getid3_temp->info['riff'];
       
$info['error'] = $getid3_temp->info['error'];
       
$info['warning'] = $getid3_temp->info['warning'];
       
$info['lpac']['comments']['comment'] = $getid3_temp->info['comments'];
       
$info['audio']['sample_rate'] = $getid3_temp->info['audio']['sample_rate'];
        unset(
$getid3_temp, $getid3_riff);

       
$info['audio']['channels'] = ($info['lpac']['flags']['stereo'] ? 2 : 1);

        if (
$info['lpac']['flags']['24_bit']) {
           
$info['audio']['bits_per_sample'] = $info['riff']['audio'][0]['bits_per_sample'];
        } elseif (
$info['lpac']['flags']['16_bit']) {
           
$info['audio']['bits_per_sample'] = 16;
        } else {
           
$info['audio']['bits_per_sample'] = 8;
        }

        if (
$info['lpac']['flags']['fast_compress']) {
            
// fast
           
$info['audio']['encoder_options'] = '-1';
        } else {
            switch (
$info['lpac']['max_prediction_order']) {
                case
20: // simple
                   
$info['audio']['encoder_options'] = '-2';
                    break;
                case
30: // medium
                   
$info['audio']['encoder_options'] = '-3';
                    break;
                case
40: // high
                   
$info['audio']['encoder_options'] = '-4';
                    break;
                case
60: // extrahigh
                   
$info['audio']['encoder_options'] = '-5';
                    break;
            }
        }

       
$info['playtime_seconds'] = $info['lpac']['total_samples'] / $info['audio']['sample_rate'];
       
$info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];

        return
true;
    }

}


?>