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.voc.php                                                 |

    18 // | Module for analyzing Creative VOC Audio files.                       |

    19 // | dependencies: NONE                                                   |

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

    21 //

    22 // $Id: module.audio.voc.php,v 1.3 2006/11/02 10:48:02 ah Exp $

    23 

    24         

    25         

    26 class getid3_voc extends getid3_handler

    27 {

    28 

    29     public function Analyze() {

    30 

    31         $getid3 = $this->getid3;

    32         

    33         $original_av_data_offset = $getid3->info['avdataoffset'];

    34         

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

    36         $voc_header= fread($getid3->fp, 26);

    37 

    38         // Magic bytes: 'Creative Voice File'

    39 

    40         $info_audio = &$getid3->info['audio'];

    41         $getid3->info['voc'] = array ();

    42         $info_voc = &$getid3->info['voc'];

    43 

    44         $getid3->info['fileformat']    = 'voc';

    45         $info_audio['dataformat']      = 'voc';

    46         $info_audio['bitrate_mode']    = 'cbr';

    47         $info_audio['lossless']        = true;

    48         $info_audio['channels']        = 1;         // might be overriden below

    49         $info_audio['bits_per_sample'] = 8;         // might be overriden below

    50 

    51         // byte #     Description

    52         // ------     ------------------------------------------

    53         // 00-12      'Creative Voice File'

    54         // 13         1A (eof to abort printing of file)

    55         // 14-15      Offset of first datablock in .voc file (std 1A 00 in Intel Notation)

    56         // 16-17      Version number (minor,major) (VOC-HDR puts 0A 01)

    57         // 18-19      2's Comp of Ver. # + 1234h (VOC-HDR puts 29 11)

    58 

    59         getid3_lib::ReadSequence('LittleEndian2Int', $info_voc['header'], $voc_header, 20,

    60             array (

    61                 'datablock_offset' => 2, 

    62                 'minor_version'    => 1, 

    63                 'major_version'    => 1  

    64             )

    65         );

    66 

    67         do {

    68             $block_offset = ftell($getid3->fp);

    69             $block_data   = fread($getid3->fp, 4);

    70             $block_type   = ord($block_data{0});

    71             $block_size   = getid3_lib::LittleEndian2Int(substr($block_data, 1, 3));

    72             $this_block   = array ();

    73 

    74             @$info_voc['blocktypes'][$block_type]++;

    75             

    76             switch ($block_type) {

    77                 

    78                 case 0:  // Terminator

    79                     // do nothing, we'll break out of the loop down below

    80                     break;

    81 

    82                 case 1:  // Sound data

    83                     $block_data .= fread($getid3->fp, 2);

    84                     if ($getid3->info['avdataoffset'] <= $original_av_data_offset) {

    85                         $getid3->info['avdataoffset'] = ftell($getid3->fp);

    86                     }

    87                     fseek($getid3->fp, $block_size - 2, SEEK_CUR);

    88 

    89                     getid3_lib::ReadSequence('LittleEndian2Int', $this_block, $block_data, 4,

    90                         array (

    91                             'sample_rate_id'   => 1,

    92                             'compression_type' => 1

    93                         )

    94                     );

    95 

    96                     $this_block['compression_name'] = getid3_voc::VOCcompressionTypeLookup($this_block['compression_type']);

    97                     if ($this_block['compression_type'] <= 3) {

    98                         $info_voc['compressed_bits_per_sample'] = (int)(str_replace('-bit', '', $this_block['compression_name']));

    99                     }

   100 

   101                     // Less accurate sample_rate calculation than the Extended block (#8) data (but better than nothing if Extended Block is not available)

   102                     if (empty($info_audio['sample_rate'])) {

   103                         // SR byte = 256 - (1000000 / sample_rate)

   104                         $info_audio['sample_rate'] = (int)floor((1000000 / (256 - $this_block['sample_rate_id'])) / $info_audio['channels']);

   105                     }

   106                     break;

   107 

   108                 case 2:  // Sound continue

   109                 case 3:  // Silence

   110                 case 4:  // Marker

   111                 case 6:  // Repeat

   112                 case 7:  // End repeat

   113                     // nothing useful, just skip

   114                     fseek($getid3->fp, $block_size, SEEK_CUR);

   115                     break;

   116 

   117                 case 8:  // Extended

   118                     $block_data .= fread($getid3->fp, 4);

   119 

   120                     //00-01  Time Constant:

   121                     //   Mono: 65536 - (256000000 / sample_rate)

   122                     // Stereo: 65536 - (256000000 / (sample_rate * 2))

   123                     getid3_lib::ReadSequence('LittleEndian2Int', $this_block, $block_data, 4,

   124                         array (

   125                             'time_constant' => 2, 

   126                             'pack_method'   => 1, 

   127                             'stereo'        => 1        

   128                         )

   129                     );

   130                     $this_block['stereo']      = (bool)$this_block['stereo'];

   131                     

   132                     $info_audio['channels']    = ($this_block['stereo'] ? 2 : 1);

   133                     $info_audio['sample_rate'] = (int)floor((256000000 / (65536 - $this_block['time_constant'])) / $info_audio['channels']);

   134                     break;

   135 

   136                 case 9:  // data block that supersedes blocks 1 and 8. Used for stereo, 16 bit

   137                     $block_data .= fread($getid3->fp, 12);

   138                     if ($getid3->info['avdataoffset'] <= $original_av_data_offset) {

   139                         $getid3->info['avdataoffset'] = ftell($getid3->fp);

   140                     }

   141                     fseek($getid3->fp, $block_size - 12, SEEK_CUR);

   142 

   143                     getid3_lib::ReadSequence('LittleEndian2Int', $this_block, $block_data, 4,

   144                         array (

   145                             'sample_rate'     => 4,

   146                             'bits_per_sample' => 1,

   147                             'channels'        => 1, 

   148                             'wFormat'         => 2 

   149                         )

   150                     );

   151                     

   152                     $this_block['compression_name'] = getid3_voc::VOCwFormatLookup($this_block['wFormat']);

   153                     if (getid3_voc::VOCwFormatActualBitsPerSampleLookup($this_block['wFormat'])) {

   154                         $info_voc['compressed_bits_per_sample'] = getid3_voc::VOCwFormatActualBitsPerSampleLookup($this_block['wFormat']);

   155                     }

   156 

   157                     $info_audio['sample_rate']     = $this_block['sample_rate'];

   158                     $info_audio['bits_per_sample'] = $this_block['bits_per_sample'];

   159                     $info_audio['channels']        = $this_block['channels'];

   160                     break;

   161 

   162                 default:

   163                     $getid3->warning('Unhandled block type "'.$block_type.'" at offset '.$block_offset);

   164                     fseek($getid3->fp, $block_size, SEEK_CUR);

   165                     break;

   166             }

   167 

   168             if (!empty($this_block)) {

   169                 $this_block['block_offset']  = $block_offset;

   170                 $this_block['block_size']    = $block_size;

   171                 $this_block['block_type_id'] = $block_type;

   172                 $info_voc['blocks'][] = $this_block;

   173             }

   174 

   175         } while (!feof($getid3->fp) && ($block_type != 0));

   176 

   177         // Terminator block doesn't have size field, so seek back 3 spaces

   178         fseek($getid3->fp, -3, SEEK_CUR);

   179 

   180         ksort($info_voc['blocktypes']);

   181 

   182         if (!empty($info_voc['compressed_bits_per_sample'])) {

   183             $getid3->info['playtime_seconds'] = (($getid3->info['avdataend'] - $getid3->info['avdataoffset']) * 8) / ($info_voc['compressed_bits_per_sample'] * $info_audio['channels'] * $info_audio['sample_rate']);

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

   185         }

   186 

   187         return true;

   188     }

   189 

   190 

   191 

   192     public static function VOCcompressionTypeLookup($index) {

   193         

   194         static $lookup = array (

   195             0 => '8-bit',

   196             1 => '4-bit',

   197             2 => '2.6-bit',

   198             3 => '2-bit'

   199         );

   200         return (isset($lookup[$index]) ? $lookup[$index] : 'Multi DAC ('.($index - 3).') channels');

   201     }

   202 

   203 

   204 

   205     public static function VOCwFormatLookup($index) {

   206         

   207         static $lookup = array (

   208             0x0000 => '8-bit unsigned PCM',

   209             0x0001 => 'Creative 8-bit to 4-bit ADPCM',

   210             0x0002 => 'Creative 8-bit to 3-bit ADPCM',

   211             0x0003 => 'Creative 8-bit to 2-bit ADPCM',

   212             0x0004 => '16-bit signed PCM',

   213             0x0006 => 'CCITT a-Law',

   214             0x0007 => 'CCITT u-Law',

   215             0x2000 => 'Creative 16-bit to 4-bit ADPCM'

   216         );

   217         return (isset($lookup[$index]) ? $lookup[$index] : false);

   218     }

   219 

   220 

   221 

   222     public static function VOCwFormatActualBitsPerSampleLookup($index) {

   223         

   224         static $lookup = array (

   225             0x0000 => 8,

   226             0x0001 => 4,

   227             0x0002 => 3,

   228             0x0003 => 2,

   229             0x0004 => 16,

   230             0x0006 => 8,

   231             0x0007 => 8,

   232             0x2000 => 4

   233         );

   234         return (isset($lookup[$index]) ? $lookup[$index] : false);

   235     }

   236 

   237 }

   238 

   239 

   240 ?>
author	Robert McIntyre <rlm@mit.edu>
date	Sun, 09 Feb 2014 20:46:57 -0500
parents	3f6b44aa6b35
children