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.mpc_old.php                                             |

    18 // | Module for analyzing Musepack/MPEG+ Audio files - SV4-SV6            |

    19 // | dependencies: NONE                                                   |

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

    21 //

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

    23 

    24         

    25         

    26 class getid3_mpc_old extends getid3_handler

    27 {

    28 

    29     public function Analyze() {

    30 

    31         $getid3 = $this->getid3;

    32         

    33         // http://www.uni-jena.de/~pfk/mpp/sv8/header.html

    34         

    35         $getid3->info['mpc']['header'] = array ();

    36         $info_mpc_header = &$getid3->info['mpc']['header'];

    37 

    38         $getid3->info['fileformat']               = 'mpc';

    39         $getid3->info['audio']['dataformat']      = 'mpc';

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

    41         $getid3->info['audio']['channels']        = 2;  // the format appears to be hardcoded for stereo only

    42         $getid3->info['audio']['lossless']        = false;

    43 

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

    45 

    46         $info_mpc_header['size'] = 8;

    47         $getid3->info['avdataoffset'] += $info_mpc_header['size'];

    48         

    49         $mpc_header_data = fread($getid3->fp, $info_mpc_header['size']);

    50             

    51         

    52         // Most of this code adapted from Jurgen Faul's MPEGplus source code - thanks Jurgen! :)

    53         $header_dword[0] = getid3_lib::LittleEndian2Int(substr($mpc_header_data, 0, 4));

    54         $header_dword[1] = getid3_lib::LittleEndian2Int(substr($mpc_header_data, 4, 4));

    55 

    56 

    57         // DDDD DDDD  CCCC CCCC  BBBB BBBB  AAAA AAAA

    58         // aaaa aaaa  abcd dddd  dddd deee  eeff ffff

    59         //

    60         // a = bitrate       = anything

    61         // b = IS            = anything

    62         // c = MS            = anything

    63         // d = streamversion = 0000000004 or 0000000005 or 0000000006

    64         // e = maxband       = anything

    65         // f = blocksize     = 000001 for SV5+, anything(?) for SV4

    66 

    67         $info_mpc_header['target_bitrate']       =       (($header_dword[0] & 0xFF800000) >> 23);

    68         $info_mpc_header['intensity_stereo']     = (bool)(($header_dword[0] & 0x00400000) >> 22);

    69         $info_mpc_header['mid-side_stereo']      = (bool)(($header_dword[0] & 0x00200000) >> 21);

    70         $info_mpc_header['stream_major_version'] =        ($header_dword[0] & 0x001FF800) >> 11;

    71         $info_mpc_header['stream_minor_version'] = 0; 

    72         $info_mpc_header['max_band']             =        ($header_dword[0] & 0x000007C0) >>  6;  // related to lowpass frequency, not sure how it translates exactly

    73         $info_mpc_header['block_size']           =        ($header_dword[0] & 0x0000003F);

    74 

    75         switch ($info_mpc_header['stream_major_version']) {

    76             case 4:

    77                 $info_mpc_header['frame_count'] = ($header_dword[1] >> 16);

    78                 break;

    79             case 5:

    80             case 6:

    81                 $info_mpc_header['frame_count'] =  $header_dword[1];

    82                 break;

    83 

    84             default:

    85                 throw new getid3_exception('Expecting 4, 5 or 6 in version field, found '.$info_mpc_header['stream_major_version'].' instead');

    86         }

    87 

    88         if (($info_mpc_header['stream_major_version'] > 4) && ($info_mpc_header['block_size'] != 1)) {

    89             $getid3->warning('Block size expected to be 1, actual value found: '.$info_mpc_header['block_size']);

    90         }

    91 

    92         $info_mpc_header['sample_rate'] = $getid3->info['audio']['sample_rate'] = 44100; // AB: used by all files up to SV7

    93         $info_mpc_header['samples']     = $info_mpc_header['frame_count'] * 1152 * $getid3->info['audio']['channels'];

    94 

    95         $getid3->info['audio']['bitrate_mode'] = $info_mpc_header['target_bitrate'] == 0 ? 'vbr' : 'cbr';

    96 

    97         $getid3->info['mpc']['bitrate']   = ($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8 * 44100 / $info_mpc_header['frame_count'] / 1152;

    98         $getid3->info['audio']['bitrate'] = $getid3->info['mpc']['bitrate'];

    99         $getid3->info['audio']['encoder'] = 'SV'.$info_mpc_header['stream_major_version'];

   100         

   101         return true;

   102     }

   103     

   104 }

   105 

   106 

   107 ?>