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   1  <?php
   2  /////////////////////////////////////////////////////////////////
   3  /// getID3() by James Heinrich <info@getid3.org>               //
   4  //  available at http://getid3.sourceforge.net                 //
   5  //            or http://www.getid3.org                         //
   6  /////////////////////////////////////////////////////////////////
   7  // See readme.txt for more details                             //
   8  /////////////////////////////////////////////////////////////////
   9  //                                                             //
  10  // module.audio.voc.php                                        //
  11  // module for analyzing Creative VOC Audio files               //
  12  // dependencies: NONE                                          //
  13  //                                                            ///
  14  /////////////////////////////////////////////////////////////////
  15  
  16  
  17  class getid3_voc
  18  {
  19  
  20  	function getid3_voc(&$fd, &$ThisFileInfo) {
  21  
  22          $OriginalAVdataOffset = $ThisFileInfo['avdataoffset'];
  23          fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
  24          $VOCheader  = fread($fd, 26);
  25  
  26          if (substr($VOCheader, 0, 19) != 'Creative Voice File') {
  27              $ThisFileInfo['error'][] = 'Expecting "Creative Voice File" at offset '.$ThisFileInfo['avdataoffset'].', found "'.substr($VOCheader, 0, 19).'"';
  28              return false;
  29          }
  30  
  31          // shortcuts
  32          $thisfile_audio = &$ThisFileInfo['audio'];
  33          $ThisFileInfo['voc'] = array();
  34          $thisfile_voc        = &$ThisFileInfo['voc'];
  35  
  36          $ThisFileInfo['fileformat']               = 'voc';
  37          $thisfile_audio['dataformat']      = 'voc';
  38          $thisfile_audio['bitrate_mode']    = 'cbr';
  39          $thisfile_audio['lossless']        = true;
  40          $thisfile_audio['channels']        = 1; // might be overriden below
  41          $thisfile_audio['bits_per_sample'] = 8; // might be overriden below
  42  
  43          // byte #     Description
  44          // ------     ------------------------------------------
  45          // 00-12      'Creative Voice File'
  46          // 13         1A (eof to abort printing of file)
  47          // 14-15      Offset of first datablock in .voc file (std 1A 00 in Intel Notation)
  48          // 16-17      Version number (minor,major) (VOC-HDR puts 0A 01)
  49          // 18-19      2's Comp of Ver. # + 1234h (VOC-HDR puts 29 11)
  50  
  51          $thisfile_voc['header']['datablock_offset'] = getid3_lib::LittleEndian2Int(substr($VOCheader, 20, 2));
  52          $thisfile_voc['header']['minor_version']    = getid3_lib::LittleEndian2Int(substr($VOCheader, 22, 1));
  53          $thisfile_voc['header']['major_version']    = getid3_lib::LittleEndian2Int(substr($VOCheader, 23, 1));
  54  
  55          do {
  56  
  57              $BlockOffset    = ftell($fd);
  58              $BlockData      = fread($fd, 4);
  59              $BlockType      = ord($BlockData{0});
  60              $BlockSize      = getid3_lib::LittleEndian2Int(substr($BlockData, 1, 3));
  61              $ThisBlock      = array();
  62  
  63              @$thisfile_voc['blocktypes'][$BlockType]++;
  64              switch ($BlockType) {
  65                  case 0:  // Terminator
  66                      // do nothing, we'll break out of the loop down below
  67                      break;
  68  
  69                  case 1:  // Sound data
  70                      $BlockData .= fread($fd, 2);
  71                      if ($ThisFileInfo['avdataoffset'] <= $OriginalAVdataOffset) {
  72                          $ThisFileInfo['avdataoffset'] = ftell($fd);
  73                      }
  74                      fseek($fd, $BlockSize - 2, SEEK_CUR);
  75  
  76                      $ThisBlock['sample_rate_id']   = getid3_lib::LittleEndian2Int(substr($BlockData, 4, 1));
  77                      $ThisBlock['compression_type'] = getid3_lib::LittleEndian2Int(substr($BlockData, 5, 1));
  78  
  79                      $ThisBlock['compression_name'] = $this->VOCcompressionTypeLookup($ThisBlock['compression_type']);
  80                      if ($ThisBlock['compression_type'] <= 3) {
  81                          $thisfile_voc['compressed_bits_per_sample'] = getid3_lib::CastAsInt(str_replace('-bit', '', $ThisBlock['compression_name']));
  82                      }
  83  
  84                      // Less accurate sample_rate calculation than the Extended block (#8) data (but better than nothing if Extended Block is not available)
  85                      if (empty($thisfile_audio['sample_rate'])) {
  86                          // SR byte = 256 - (1000000 / sample_rate)
  87                          $thisfile_audio['sample_rate'] = getid3_lib::trunc((1000000 / (256 - $ThisBlock['sample_rate_id'])) / $thisfile_audio['channels']);
  88                      }
  89                      break;
  90  
  91                  case 2:  // Sound continue
  92                  case 3:  // Silence
  93                  case 4:  // Marker
  94                  case 6:  // Repeat
  95                  case 7:  // End repeat
  96                      // nothing useful, just skip
  97                      fseek($fd, $BlockSize, SEEK_CUR);
  98                      break;
  99  
 100                  case 8:  // Extended
 101                      $BlockData .= fread($fd, 4);
 102  
 103                      //00-01  Time Constant:
 104                      //   Mono: 65536 - (256000000 / sample_rate)
 105                      // Stereo: 65536 - (256000000 / (sample_rate * 2))
 106                      $ThisBlock['time_constant'] =        getid3_lib::LittleEndian2Int(substr($BlockData, 4, 2));
 107                      $ThisBlock['pack_method']   =        getid3_lib::LittleEndian2Int(substr($BlockData, 6, 1));
 108                      $ThisBlock['stereo']        = (bool) getid3_lib::LittleEndian2Int(substr($BlockData, 7, 1));
 109  
 110                      $thisfile_audio['channels']    = ($ThisBlock['stereo'] ? 2 : 1);
 111                      $thisfile_audio['sample_rate'] = getid3_lib::trunc((256000000 / (65536 - $ThisBlock['time_constant'])) / $thisfile_audio['channels']);
 112                      break;
 113  
 114                  case 9:  // data block that supersedes blocks 1 and 8. Used for stereo, 16 bit
 115                      $BlockData .= fread($fd, 12);
 116                      if ($ThisFileInfo['avdataoffset'] <= $OriginalAVdataOffset) {
 117                          $ThisFileInfo['avdataoffset'] = ftell($fd);
 118                      }
 119                      fseek($fd, $BlockSize - 12, SEEK_CUR);
 120  
 121                      $ThisBlock['sample_rate']      = getid3_lib::LittleEndian2Int(substr($BlockData,  4, 4));
 122                      $ThisBlock['bits_per_sample']  = getid3_lib::LittleEndian2Int(substr($BlockData,  8, 1));
 123                      $ThisBlock['channels']         = getid3_lib::LittleEndian2Int(substr($BlockData,  9, 1));
 124                      $ThisBlock['wFormat']          = getid3_lib::LittleEndian2Int(substr($BlockData, 10, 2));
 125  
 126                      $ThisBlock['compression_name'] = $this->VOCwFormatLookup($ThisBlock['wFormat']);
 127                      if ($this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat'])) {
 128                          $thisfile_voc['compressed_bits_per_sample'] = $this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat']);
 129                      }
 130  
 131                      $thisfile_audio['sample_rate']     = $ThisBlock['sample_rate'];
 132                      $thisfile_audio['bits_per_sample'] = $ThisBlock['bits_per_sample'];
 133                      $thisfile_audio['channels']        = $ThisBlock['channels'];
 134                      break;
 135  
 136                  default:
 137                      $ThisFileInfo['warning'][] = 'Unhandled block type "'.$BlockType.'" at offset '.$BlockOffset;
 138                      fseek($fd, $BlockSize, SEEK_CUR);
 139                      break;
 140              }
 141  
 142              if (!empty($ThisBlock)) {
 143                  $ThisBlock['block_offset']  = $BlockOffset;
 144                  $ThisBlock['block_size']    = $BlockSize;
 145                  $ThisBlock['block_type_id'] = $BlockType;
 146                  $thisfile_voc['blocks'][] = $ThisBlock;
 147              }
 148  
 149          } while (!feof($fd) && ($BlockType != 0));
 150  
 151          // Terminator block doesn't have size field, so seek back 3 spaces
 152          fseek($fd, -3, SEEK_CUR);
 153  
 154          ksort($thisfile_voc['blocktypes']);
 155  
 156          if (!empty($thisfile_voc['compressed_bits_per_sample'])) {
 157              $ThisFileInfo['playtime_seconds'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / ($thisfile_voc['compressed_bits_per_sample'] * $thisfile_audio['channels'] * $thisfile_audio['sample_rate']);
 158              $thisfile_audio['bitrate'] = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['playtime_seconds'];
 159          }
 160  
 161          return true;
 162      }
 163  
 164  	function VOCcompressionTypeLookup($index) {
 165          static $VOCcompressionTypeLookup = array(
 166              0 => '8-bit',
 167              1 => '4-bit',
 168              2 => '2.6-bit',
 169              3 => '2-bit'
 170          );
 171          return (isset($VOCcompressionTypeLookup[$index]) ? $VOCcompressionTypeLookup[$index] : 'Multi DAC ('.($index - 3).') channels');
 172      }
 173  
 174  	function VOCwFormatLookup($index) {
 175          static $VOCwFormatLookup = array(
 176              0x0000 => '8-bit unsigned PCM',
 177              0x0001 => 'Creative 8-bit to 4-bit ADPCM',
 178              0x0002 => 'Creative 8-bit to 3-bit ADPCM',
 179              0x0003 => 'Creative 8-bit to 2-bit ADPCM',
 180              0x0004 => '16-bit signed PCM',
 181              0x0006 => 'CCITT a-Law',
 182              0x0007 => 'CCITT u-Law',
 183              0x2000 => 'Creative 16-bit to 4-bit ADPCM'
 184          );
 185          return (isset($VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
 186      }
 187  
 188  	function VOCwFormatActualBitsPerSampleLookup($index) {
 189          static $VOCwFormatLookup = array(
 190              0x0000 => 8,
 191              0x0001 => 4,
 192              0x0002 => 3,
 193              0x0003 => 2,
 194              0x0004 => 16,
 195              0x0006 => 8,
 196              0x0007 => 8,
 197              0x2000 => 4
 198          );
 199          return (isset($VOCwFormatLookup[$index]) ? $VOCwFormatLookup[$index] : false);
 200      }
 201  
 202  }
 203  
 204  
 205  ?>