Mercurial > judyates

     1 <?php

     2 // +----------------------------------------------------------------------+

     3 // | PHP version 5                                                        |

     4 // +----------------------------------------------------------------------+

     5 // | Copyright (c) 2002-2006 James Heinrich, Allan Hansen                 |

     6 // +----------------------------------------------------------------------+

     7 // | This source file is subject to version 2 of the GPL license,         |

     8 // | that is bundled with this package in the file license.txt and is     |

     9 // | available through the world-wide-web at the following url:           |

    10 // | http://www.gnu.org/copyleft/gpl.html                                 |

    11 // +----------------------------------------------------------------------+

    12 // | getID3() - http://getid3.sourceforge.net or http://www.getid3.org    |

    13 // +----------------------------------------------------------------------+

    14 // | Authors: James Heinrich <infoØgetid3*org>                            |

    15 // |          Allan Hansen <ahØartemis*dk>                                |

    16 // +----------------------------------------------------------------------+

    17 // | module.audio.lpac.php                                                |

    18 // | Module for analyzing LPAC Audio files                                |

    19 // | dependencies: module.audio-video.riff.php                            |

    20 // +----------------------------------------------------------------------+

    21 //

    22 // $Id: module.audio.lpac.php,v 1.2 2006/11/02 10:48:01 ah Exp $

    23 

    24         

    25         

    26 class getid3_lpac extends getid3_handler

    27 {

    28 

    29     public function Analyze() {

    30         

    31         $getid3 = $this->getid3;

    32         

    33         $getid3->include_module('audio-video.riff');

    34         

    35         // Magic bytes - 'LPAC'

    36         

    37         fseek($getid3->fp, $getid3->info['avdataoffset'], SEEK_SET);

    38         $lpac_header = fread($getid3->fp, 14);

    39         

    40         $getid3->info['avdataoffset'] += 14;

    41         

    42         $getid3->info['lpac'] = array ();

    43         $info_lpac = &$getid3->info['lpac'];

    44 

    45         $getid3->info['fileformat']               = 'lpac';

    46         $getid3->info['audio']['dataformat']      = 'lpac';

    47         $getid3->info['audio']['lossless']        = true;

    48         $getid3->info['audio']['bitrate_mode']    = 'vbr';

    49                                                   

    50         $info_lpac['file_version']     = getid3_lib::BigEndian2Int($lpac_header{4});

    51         $flags['audio_type']                      = getid3_lib::BigEndian2Int($lpac_header{5});

    52         $info_lpac['total_samples']    = getid3_lib::BigEndian2Int(substr($lpac_header,  6, 4));

    53         $flags['parameters']                      = getid3_lib::BigEndian2Int(substr($lpac_header, 10, 4));

    54 

    55         $info_lpac['flags']['is_wave'] = (bool)($flags['audio_type'] & 0x40);

    56         $info_lpac['flags']['stereo']  = (bool)($flags['audio_type'] & 0x04);

    57         $info_lpac['flags']['24_bit']  = (bool)($flags['audio_type'] & 0x02);

    58         $info_lpac['flags']['16_bit']  = (bool)($flags['audio_type'] & 0x01);

    59 

    60         if ($info_lpac['flags']['24_bit'] && $info_lpac['flags']['16_bit']) {

    61             $getid3->warning('24-bit and 16-bit flags cannot both be set');

    62         }

    63 

    64         $info_lpac['flags']['fast_compress']             =   (bool)($flags['parameters'] & 0x40000000);

    65         $info_lpac['flags']['random_access']             =   (bool)($flags['parameters'] & 0x08000000);

    66         $info_lpac['block_length']                       = pow(2, (($flags['parameters'] & 0x07000000) >> 24)) * 256;

    67         $info_lpac['flags']['adaptive_prediction_order'] =   (bool)($flags['parameters'] & 0x00800000);

    68         $info_lpac['flags']['adaptive_quantization']     =   (bool)($flags['parameters'] & 0x00400000);

    69         $info_lpac['flags']['joint_stereo']              =   (bool)($flags['parameters'] & 0x00040000);

    70         $info_lpac['quantization']                       =         ($flags['parameters'] & 0x00001F00) >> 8;

    71         $info_lpac['max_prediction_order']               =         ($flags['parameters'] & 0x0000003F);

    72 

    73         if ($info_lpac['flags']['fast_compress'] && ($info_lpac['max_prediction_order'] != 3)) {

    74             $getid3->warning('max_prediction_order expected to be "3" if fast_compress is true, actual value is "'.$info_lpac['max_prediction_order'].'"');

    75         }

    76         

    77         switch ($info_lpac['file_version']) {

    78         

    79             case 6:

    80                 if ($info_lpac['flags']['adaptive_quantization']) {

    81                     $getid3->warning('adaptive_quantization expected to be false in LPAC file stucture v6, actually true');

    82                 }

    83                 if ($info_lpac['quantization'] != 20) {

    84                     $getid3->warning('Quantization expected to be 20 in LPAC file stucture v6, actually '.$info_lpac['flags']['Q']);

    85                 }

    86                 break;

    87 

    88         

    89             default:

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

    91                 break;

    92         }

    93 

    94         // Clone getid3 - messing with something - better safe than sorry

    95         $clone = clone $getid3;

    96         

    97         // Analyze clone by fp

    98         $riff = new getid3_riff($clone);

    99         $riff->Analyze();

   100         

   101         // Import from clone and destroy

   102         $getid3->info['avdataoffset']                = $clone->info['avdataoffset'];

   103         $getid3->info['riff']                        = $clone->info['riff'];

   104         //$info_lpac['comments']['comment'] = $clone->info['comments'];

   105         $getid3->info['audio']['sample_rate']        = $clone->info['audio']['sample_rate'];

   106         $getid3->warnings($clone->warnings());

   107         unset($clone);

   108         

   109         $getid3->info['audio']['channels'] = ($info_lpac['flags']['stereo'] ? 2 : 1);

   110 

   111         if ($info_lpac['flags']['24_bit']) {

   112             $getid3->info['audio']['bits_per_sample'] = $getid3->info['riff']['audio'][0]['bits_per_sample'];

   113         } elseif ($info_lpac['flags']['16_bit']) {

   114             $getid3->info['audio']['bits_per_sample'] = 16;

   115         } else {

   116             $getid3->info['audio']['bits_per_sample'] = 8;

   117         }

   118 

   119         if ($info_lpac['flags']['fast_compress']) {

   120              // fast

   121             $getid3->info['audio']['encoder_options'] = '-1';

   122         } else {

   123             switch ($info_lpac['max_prediction_order']) {

   124                 case 20: // simple

   125                     $getid3->info['audio']['encoder_options'] = '-2';

   126                     break;

   127                 case 30: // medium

   128                     $getid3->info['audio']['encoder_options'] = '-3';

   129                     break;

   130                 case 40: // high

   131                     $getid3->info['audio']['encoder_options'] = '-4';

   132                     break;

   133                 case 60: // extrahigh

   134                     $getid3->info['audio']['encoder_options'] = '-5';

   135                     break;

   136             }

   137         }

   138 

   139         $getid3->info['playtime_seconds'] = $info_lpac['total_samples'] / $getid3->info['audio']['sample_rate'];

   140         $getid3->info['audio']['bitrate'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / $getid3->info['playtime_seconds'];

   141 

   142         return true;

   143     }

   144 

   145 }

   146 

   147 

   148 ?>