vendor/james-heinrich/getid3/getid3/module.audio.mpc.php

   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 //          also https://github.com/JamesHeinrich/getID3       //
   7 /////////////////////////////////////////////////////////////////
   8 // See readme.txt for more details                             //
   9 /////////////////////////////////////////////////////////////////
  10 //                                                             //
  11 // module.audio.mpc.php                                        //
  12 // module for analyzing Musepack/MPEG+ Audio files             //
  13 // dependencies: NONE                                          //
  14 //                                                            ///
  15 /////////////////////////////////////////////////////////////////
  16
  17
  18 class getid3_mpc extends getid3_handler
  19 {
  20
  21         public function Analyze() {
  22                 $info = &$this->getid3->info;
  23
  24                 $info['mpc']['header'] = array();
  25                 $thisfile_mpc_header   = &$info['mpc']['header'];
  26
  27                 $info['fileformat']               = 'mpc';
  28                 $info['audio']['dataformat']      = 'mpc';
  29                 $info['audio']['bitrate_mode']    = 'vbr';
  30                 $info['audio']['channels']        = 2;  // up to SV7 the format appears to have been hardcoded for stereo only
  31                 $info['audio']['lossless']        = false;
  32
  33                 $this->fseek($info['avdataoffset']);
  34                 $MPCheaderData = $this->fread(4);
  35                 $info['mpc']['header']['preamble'] = substr($MPCheaderData, 0, 4); // should be 'MPCK' (SV8) or 'MP+' (SV7), otherwise possible stream data (SV4-SV6)
  36                 if (preg_match('#^MPCK#', $info['mpc']['header']['preamble'])) {
  37
  38                         // this is SV8
  39                         return $this->ParseMPCsv8();
  40
  41                 } elseif (preg_match('#^MP\+#', $info['mpc']['header']['preamble'])) {
  42
  43                         // this is SV7
  44                         return $this->ParseMPCsv7();
  45
  46                 } elseif (preg_match('/^[\x00\x01\x10\x11\x40\x41\x50\x51\x80\x81\x90\x91\xC0\xC1\xD0\xD1][\x20-37][\x00\x20\x40\x60\x80\xA0\xC0\xE0]/s', $MPCheaderData)) {
  47
  48                         // this is SV4 - SV6, handle seperately
  49                         return $this->ParseMPCsv6();
  50
  51                 } else {
  52
  53                         $this->error('Expecting "MP+" or "MPCK" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes(substr($MPCheaderData, 0, 4)).'"');
  54                         unset($info['fileformat']);
  55                         unset($info['mpc']);
  56                         return false;
  57
  58                 }
  59                 return false;
  60         }
  61
  62
  63         public function ParseMPCsv8() {
  64                 // this is SV8
  65                 // http://trac.musepack.net/trac/wiki/SV8Specification
  66
  67                 $info = &$this->getid3->info;
  68                 $thisfile_mpc_header = &$info['mpc']['header'];
  69
  70                 $keyNameSize            = 2;
  71                 $maxHandledPacketLength = 9; // specs say: "n*8; 0 < n < 10"
  72
  73                 $offset = $this->ftell();
  74                 while ($offset < $info['avdataend']) {
  75                         $thisPacket = array();
  76                         $thisPacket['offset'] = $offset;
  77                         $packet_offset = 0;
  78
  79                         // Size is a variable-size field, could be 1-4 bytes (possibly more?)
  80                         // read enough data in and figure out the exact size later
  81                         $MPCheaderData = $this->fread($keyNameSize + $maxHandledPacketLength);
  82                         $packet_offset += $keyNameSize;
  83                         $thisPacket['key']      = substr($MPCheaderData, 0, $keyNameSize);
  84                         $thisPacket['key_name'] = $this->MPCsv8PacketName($thisPacket['key']);
  85                         if ($thisPacket['key'] == $thisPacket['key_name']) {
  86                                 $this->error('Found unexpected key value "'.$thisPacket['key'].'" at offset '.$thisPacket['offset']);
  87                                 return false;
  88                         }
  89                         $packetLength = 0;
  90                         $thisPacket['packet_size'] = $this->SV8variableLengthInteger(substr($MPCheaderData, $keyNameSize), $packetLength); // includes keyname and packet_size field
  91                         if ($thisPacket['packet_size'] === false) {
  92                                 $this->error('Did not find expected packet length within '.$maxHandledPacketLength.' bytes at offset '.($thisPacket['offset'] + $keyNameSize));
  93                                 return false;
  94                         }
  95                         $packet_offset += $packetLength;
  96                         $offset += $thisPacket['packet_size'];
  97
  98                         switch ($thisPacket['key']) {
  99                                 case 'SH': // Stream Header
 100                                         $moreBytesToRead = $thisPacket['packet_size'] - $keyNameSize - $maxHandledPacketLength;
 101                                         if ($moreBytesToRead > 0) {
 102                                                 $MPCheaderData .= $this->fread($moreBytesToRead);
 103                                         }
 104                                         $thisPacket['crc']               =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 4));
 105                                         $packet_offset += 4;
 106                                         $thisPacket['stream_version']    =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1));
 107                                         $packet_offset += 1;
 108
 109                                         $packetLength = 0;
 110                                         $thisPacket['sample_count']      = $this->SV8variableLengthInteger(substr($MPCheaderData, $packet_offset, $maxHandledPacketLength), $packetLength);
 111                                         $packet_offset += $packetLength;
 112
 113                                         $packetLength = 0;
 114                                         $thisPacket['beginning_silence'] = $this->SV8variableLengthInteger(substr($MPCheaderData, $packet_offset, $maxHandledPacketLength), $packetLength);
 115                                         $packet_offset += $packetLength;
 116
 117                                         $otherUsefulData                 =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2));
 118                                         $packet_offset += 2;
 119                                         $thisPacket['sample_frequency_raw'] =        (($otherUsefulData & 0xE000) >> 13);
 120                                         $thisPacket['max_bands_used']       =        (($otherUsefulData & 0x1F00) >>  8);
 121                                         $thisPacket['channels']             =        (($otherUsefulData & 0x00F0) >>  4) + 1;
 122                                         $thisPacket['ms_used']              = (bool) (($otherUsefulData & 0x0008) >>  3);
 123                                         $thisPacket['audio_block_frames']   =        (($otherUsefulData & 0x0007) >>  0);
 124                                         $thisPacket['sample_frequency']     = $this->MPCfrequencyLookup($thisPacket['sample_frequency_raw']);
 125
 126                                         $thisfile_mpc_header['mid_side_stereo']      = $thisPacket['ms_used'];
 127                                         $thisfile_mpc_header['sample_rate']          = $thisPacket['sample_frequency'];
 128                                         $thisfile_mpc_header['samples']              = $thisPacket['sample_count'];
 129                                         $thisfile_mpc_header['stream_version_major'] = $thisPacket['stream_version'];
 130
 131                                         $info['audio']['channels']    = $thisPacket['channels'];
 132                                         $info['audio']['sample_rate'] = $thisPacket['sample_frequency'];
 133                                         $info['playtime_seconds'] = $thisPacket['sample_count'] / $thisPacket['sample_frequency'];
 134                                         $info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
 135                                         break;
 136
 137                                 case 'RG': // Replay Gain
 138                                         $moreBytesToRead = $thisPacket['packet_size'] - $keyNameSize - $maxHandledPacketLength;
 139                                         if ($moreBytesToRead > 0) {
 140                                                 $MPCheaderData .= $this->fread($moreBytesToRead);
 141                                         }
 142                                         $thisPacket['replaygain_version']     =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1));
 143                                         $packet_offset += 1;
 144                                         $thisPacket['replaygain_title_gain']  =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2));
 145                                         $packet_offset += 2;
 146                                         $thisPacket['replaygain_title_peak']  =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2));
 147                                         $packet_offset += 2;
 148                                         $thisPacket['replaygain_album_gain']  =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2));
 149                                         $packet_offset += 2;
 150                                         $thisPacket['replaygain_album_peak']  =       getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2));
 151                                         $packet_offset += 2;
 152
 153                                         if ($thisPacket['replaygain_title_gain']) { $info['replay_gain']['title']['gain'] = $thisPacket['replaygain_title_gain']; }
 154                                         if ($thisPacket['replaygain_title_peak']) { $info['replay_gain']['title']['peak'] = $thisPacket['replaygain_title_peak']; }
 155                                         if ($thisPacket['replaygain_album_gain']) { $info['replay_gain']['album']['gain'] = $thisPacket['replaygain_album_gain']; }
 156                                         if ($thisPacket['replaygain_album_peak']) { $info['replay_gain']['album']['peak'] = $thisPacket['replaygain_album_peak']; }
 157                                         break;
 158
 159                                 case 'EI': // Encoder Info
 160                                         $moreBytesToRead = $thisPacket['packet_size'] - $keyNameSize - $maxHandledPacketLength;
 161                                         if ($moreBytesToRead > 0) {
 162                                                 $MPCheaderData .= $this->fread($moreBytesToRead);
 163                                         }
 164                                         $profile_pns                 = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1));
 165                                         $packet_offset += 1;
 166                                         $quality_int =                   (($profile_pns & 0xF0) >> 4);
 167                                         $quality_dec =                   (($profile_pns & 0x0E) >> 3);
 168                                         $thisPacket['quality'] = (float) $quality_int + ($quality_dec / 8);
 169                                         $thisPacket['pns_tool'] = (bool) (($profile_pns & 0x01) >> 0);
 170                                         $thisPacket['version_major'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1));
 171                                         $packet_offset += 1;
 172                                         $thisPacket['version_minor'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1));
 173                                         $packet_offset += 1;
 174                                         $thisPacket['version_build'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1));
 175                                         $packet_offset += 1;
 176                                         $thisPacket['version'] = $thisPacket['version_major'].'.'.$thisPacket['version_minor'].'.'.$thisPacket['version_build'];
 177
 178                                         $info['audio']['encoder'] = 'MPC v'.$thisPacket['version'].' ('.(($thisPacket['version_minor'] % 2) ? 'unstable' : 'stable').')';
 179                                         $thisfile_mpc_header['encoder_version'] = $info['audio']['encoder'];
 180                                         //$thisfile_mpc_header['quality']         = (float) ($thisPacket['quality'] / 1.5875); // values can range from 0.000 to 15.875, mapped to qualities of 0.0 to 10.0
 181                                         $thisfile_mpc_header['quality']         = (float) ($thisPacket['quality'] - 5); // values can range from 0.000 to 15.875, of which 0..4 are "reserved/experimental", and 5..15 are mapped to qualities of 0.0 to 10.0
 182                                         break;
 183
 184                                 case 'SO': // Seek Table Offset
 185                                         $packetLength = 0;
 186                                         $thisPacket['seek_table_offset'] = $thisPacket['offset'] + $this->SV8variableLengthInteger(substr($MPCheaderData, $packet_offset, $maxHandledPacketLength), $packetLength);
 187                                         $packet_offset += $packetLength;
 188                                         break;
 189
 190                                 case 'ST': // Seek Table
 191                                 case 'SE': // Stream End
 192                                 case 'AP': // Audio Data
 193                                         // nothing useful here, just skip this packet
 194                                         $thisPacket = array();
 195                                         break;
 196
 197                                 default:
 198                                         $this->error('Found unhandled key type "'.$thisPacket['key'].'" at offset '.$thisPacket['offset']);
 199                                         return false;
 200                                         break;
 201                         }
 202                         if (!empty($thisPacket)) {
 203                                 $info['mpc']['packets'][] = $thisPacket;
 204                         }
 205                         $this->fseek($offset);
 206                 }
 207                 $thisfile_mpc_header['size'] = $offset;
 208                 return true;
 209         }
 210
 211         public function ParseMPCsv7() {
 212                 // this is SV7
 213                 // http://www.uni-jena.de/~pfk/mpp/sv8/header.html
 214
 215                 $info = &$this->getid3->info;
 216                 $thisfile_mpc_header = &$info['mpc']['header'];
 217                 $offset = 0;
 218
 219                 $thisfile_mpc_header['size'] = 28;
 220                 $MPCheaderData  = $info['mpc']['header']['preamble'];
 221                 $MPCheaderData .= $this->fread($thisfile_mpc_header['size'] - strlen($info['mpc']['header']['preamble']));
 222                 $offset = strlen('MP+');
 223
 224                 $StreamVersionByte                           = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 1));
 225                 $offset += 1;
 226                 $thisfile_mpc_header['stream_version_major'] = ($StreamVersionByte & 0x0F) >> 0;
 227                 $thisfile_mpc_header['stream_version_minor'] = ($StreamVersionByte & 0xF0) >> 4; // should always be 0, subversions no longer exist in SV8
 228                 $thisfile_mpc_header['frame_count']          = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 4));
 229                 $offset += 4;
 230
 231                 if ($thisfile_mpc_header['stream_version_major'] != 7) {
 232                         $this->error('Only Musepack SV7 supported (this file claims to be v'.$thisfile_mpc_header['stream_version_major'].')');
 233                         return false;
 234                 }
 235
 236                 $FlagsDWORD1                                   = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 4));
 237                 $offset += 4;
 238                 $thisfile_mpc_header['intensity_stereo']       = (bool) (($FlagsDWORD1 & 0x80000000) >> 31);
 239                 $thisfile_mpc_header['mid_side_stereo']        = (bool) (($FlagsDWORD1 & 0x40000000) >> 30);
 240                 $thisfile_mpc_header['max_subband']            =         ($FlagsDWORD1 & 0x3F000000) >> 24;
 241                 $thisfile_mpc_header['raw']['profile']         =         ($FlagsDWORD1 & 0x00F00000) >> 20;
 242                 $thisfile_mpc_header['begin_loud']             = (bool) (($FlagsDWORD1 & 0x00080000) >> 19);
 243                 $thisfile_mpc_header['end_loud']               = (bool) (($FlagsDWORD1 & 0x00040000) >> 18);
 244                 $thisfile_mpc_header['raw']['sample_rate']     =         ($FlagsDWORD1 & 0x00030000) >> 16;
 245                 $thisfile_mpc_header['max_level']              =         ($FlagsDWORD1 & 0x0000FFFF);
 246
 247                 $thisfile_mpc_header['raw']['title_peak']      = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2));
 248                 $offset += 2;
 249                 $thisfile_mpc_header['raw']['title_gain']      = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2), true);
 250                 $offset += 2;
 251
 252                 $thisfile_mpc_header['raw']['album_peak']      = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2));
 253                 $offset += 2;
 254                 $thisfile_mpc_header['raw']['album_gain']      = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2), true);
 255                 $offset += 2;
 256
 257                 $FlagsDWORD2                                   = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 4));
 258                 $offset += 4;
 259                 $thisfile_mpc_header['true_gapless']           = (bool) (($FlagsDWORD2 & 0x80000000) >> 31);
 260                 $thisfile_mpc_header['last_frame_length']      =         ($FlagsDWORD2 & 0x7FF00000) >> 20;
 261
 262
 263                 $thisfile_mpc_header['raw']['not_sure_what']   = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 3));
 264                 $offset += 3;
 265                 $thisfile_mpc_header['raw']['encoder_version'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 1));
 266                 $offset += 1;
 267
 268                 $thisfile_mpc_header['profile']     = $this->MPCprofileNameLookup($thisfile_mpc_header['raw']['profile']);
 269                 $thisfile_mpc_header['sample_rate'] = $this->MPCfrequencyLookup($thisfile_mpc_header['raw']['sample_rate']);
 270                 if ($thisfile_mpc_header['sample_rate'] == 0) {
 271                         $this->error('Corrupt MPC file: frequency == zero');
 272                         return false;
 273                 }
 274                 $info['audio']['sample_rate'] = $thisfile_mpc_header['sample_rate'];
 275                 $thisfile_mpc_header['samples']       = ((($thisfile_mpc_header['frame_count'] - 1) * 1152) + $thisfile_mpc_header['last_frame_length']) * $info['audio']['channels'];
 276
 277                 $info['playtime_seconds']     = ($thisfile_mpc_header['samples'] / $info['audio']['channels']) / $info['audio']['sample_rate'];
 278                 if ($info['playtime_seconds'] == 0) {
 279                         $this->error('Corrupt MPC file: playtime_seconds == zero');
 280                         return false;
 281                 }
 282
 283                 // add size of file header to avdataoffset - calc bitrate correctly + MD5 data
 284                 $info['avdataoffset'] += $thisfile_mpc_header['size'];
 285
 286                 $info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
 287
 288                 $thisfile_mpc_header['title_peak']        = $thisfile_mpc_header['raw']['title_peak'];
 289                 $thisfile_mpc_header['title_peak_db']     = $this->MPCpeakDBLookup($thisfile_mpc_header['title_peak']);
 290                 if ($thisfile_mpc_header['raw']['title_gain'] < 0) {
 291                         $thisfile_mpc_header['title_gain_db'] = (float) (32768 + $thisfile_mpc_header['raw']['title_gain']) / -100;
 292                 } else {
 293                         $thisfile_mpc_header['title_gain_db'] = (float) $thisfile_mpc_header['raw']['title_gain'] / 100;
 294                 }
 295
 296                 $thisfile_mpc_header['album_peak']        = $thisfile_mpc_header['raw']['album_peak'];
 297                 $thisfile_mpc_header['album_peak_db']     = $this->MPCpeakDBLookup($thisfile_mpc_header['album_peak']);
 298                 if ($thisfile_mpc_header['raw']['album_gain'] < 0) {
 299                         $thisfile_mpc_header['album_gain_db'] = (float) (32768 + $thisfile_mpc_header['raw']['album_gain']) / -100;
 300                 } else {
 301                         $thisfile_mpc_header['album_gain_db'] = (float) $thisfile_mpc_header['raw']['album_gain'] / 100;;
 302                 }
 303                 $thisfile_mpc_header['encoder_version']   = $this->MPCencoderVersionLookup($thisfile_mpc_header['raw']['encoder_version']);
 304
 305                 $info['replay_gain']['track']['adjustment'] = $thisfile_mpc_header['title_gain_db'];
 306                 $info['replay_gain']['album']['adjustment'] = $thisfile_mpc_header['album_gain_db'];
 307
 308                 if ($thisfile_mpc_header['title_peak'] > 0) {
 309                         $info['replay_gain']['track']['peak'] = $thisfile_mpc_header['title_peak'];
 310                 } elseif (round($thisfile_mpc_header['max_level'] * 1.18) > 0) {
 311                         $info['replay_gain']['track']['peak'] = getid3_lib::CastAsInt(round($thisfile_mpc_header['max_level'] * 1.18)); // why? I don't know - see mppdec.c
 312                 }
 313                 if ($thisfile_mpc_header['album_peak'] > 0) {
 314                         $info['replay_gain']['album']['peak'] = $thisfile_mpc_header['album_peak'];
 315                 }
 316
 317                 //$info['audio']['encoder'] = 'SV'.$thisfile_mpc_header['stream_version_major'].'.'.$thisfile_mpc_header['stream_version_minor'].', '.$thisfile_mpc_header['encoder_version'];
 318                 $info['audio']['encoder'] = $thisfile_mpc_header['encoder_version'];
 319                 $info['audio']['encoder_options'] = $thisfile_mpc_header['profile'];
 320                 $thisfile_mpc_header['quality'] = (float) ($thisfile_mpc_header['raw']['profile'] - 5); // values can range from 0 to 15, of which 0..4 are "reserved/experimental", and 5..15 are mapped to qualities of 0.0 to 10.0
 321
 322                 return true;
 323         }
 324
 325         public function ParseMPCsv6() {
 326                 // this is SV4 - SV6
 327
 328                 $info = &$this->getid3->info;
 329                 $thisfile_mpc_header = &$info['mpc']['header'];
 330                 $offset = 0;
 331
 332                 $thisfile_mpc_header['size'] = 8;
 333                 $this->fseek($info['avdataoffset']);
 334                 $MPCheaderData = $this->fread($thisfile_mpc_header['size']);
 335
 336                 // add size of file header to avdataoffset - calc bitrate correctly + MD5 data
 337                 $info['avdataoffset'] += $thisfile_mpc_header['size'];
 338
 339                 // Most of this code adapted from Jurgen Faul's MPEGplus source code - thanks Jurgen! :)
 340                 $HeaderDWORD[0] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, 0, 4));
 341                 $HeaderDWORD[1] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, 4, 4));
 342
 343
 344                 // DDDD DDDD  CCCC CCCC  BBBB BBBB  AAAA AAAA
 345                 // aaaa aaaa  abcd dddd  dddd deee  eeff ffff
 346                 //
 347                 // a = bitrate       = anything
 348                 // b = IS            = anything
 349                 // c = MS            = anything
 350                 // d = streamversion = 0000000004 or 0000000005 or 0000000006
 351                 // e = maxband       = anything
 352                 // f = blocksize     = 000001 for SV5+, anything(?) for SV4
 353
 354                 $thisfile_mpc_header['target_bitrate']       =        (($HeaderDWORD[0] & 0xFF800000) >> 23);
 355                 $thisfile_mpc_header['intensity_stereo']     = (bool) (($HeaderDWORD[0] & 0x00400000) >> 22);
 356                 $thisfile_mpc_header['mid_side_stereo']      = (bool) (($HeaderDWORD[0] & 0x00200000) >> 21);
 357                 $thisfile_mpc_header['stream_version_major'] =         ($HeaderDWORD[0] & 0x001FF800) >> 11;
 358                 $thisfile_mpc_header['stream_version_minor'] = 0; // no sub-version numbers before SV7
 359                 $thisfile_mpc_header['max_band']             =         ($HeaderDWORD[0] & 0x000007C0) >>  6;  // related to lowpass frequency, not sure how it translates exactly
 360                 $thisfile_mpc_header['block_size']           =         ($HeaderDWORD[0] & 0x0000003F);
 361
 362                 switch ($thisfile_mpc_header['stream_version_major']) {
 363                         case 4:
 364                                 $thisfile_mpc_header['frame_count'] = ($HeaderDWORD[1] >> 16);
 365                                 break;
 366
 367                         case 5:
 368                         case 6:
 369                                 $thisfile_mpc_header['frame_count'] =  $HeaderDWORD[1];
 370                                 break;
 371
 372                         default:
 373                                 $info['error'] = 'Expecting 4, 5 or 6 in version field, found '.$thisfile_mpc_header['stream_version_major'].' instead';
 374                                 unset($info['mpc']);
 375                                 return false;
 376                                 break;
 377                 }
 378
 379                 if (($thisfile_mpc_header['stream_version_major'] > 4) && ($thisfile_mpc_header['block_size'] != 1)) {
 380                         $this->warning('Block size expected to be 1, actual value found: '.$thisfile_mpc_header['block_size']);
 381                 }
 382
 383                 $thisfile_mpc_header['sample_rate']   = 44100; // AB: used by all files up to SV7
 384                 $info['audio']['sample_rate'] = $thisfile_mpc_header['sample_rate'];
 385                 $thisfile_mpc_header['samples']       = $thisfile_mpc_header['frame_count'] * 1152 * $info['audio']['channels'];
 386
 387                 if ($thisfile_mpc_header['target_bitrate'] == 0) {
 388                         $info['audio']['bitrate_mode'] = 'vbr';
 389                 } else {
 390                         $info['audio']['bitrate_mode'] = 'cbr';
 391                 }
 392
 393                 $info['mpc']['bitrate']   = ($info['avdataend'] - $info['avdataoffset']) * 8 * 44100 / $thisfile_mpc_header['frame_count'] / 1152;
 394                 $info['audio']['bitrate'] = $info['mpc']['bitrate'];
 395                 $info['audio']['encoder'] = 'SV'.$thisfile_mpc_header['stream_version_major'];
 396
 397                 return true;
 398         }
 399
 400
 401         public function MPCprofileNameLookup($profileid) {
 402                 static $MPCprofileNameLookup = array(
 403                         0  => 'no profile',
 404                         1  => 'Experimental',
 405                         2  => 'unused',
 406                         3  => 'unused',
 407                         4  => 'unused',
 408                         5  => 'below Telephone (q = 0.0)',
 409                         6  => 'below Telephone (q = 1.0)',
 410                         7  => 'Telephone (q = 2.0)',
 411                         8  => 'Thumb (q = 3.0)',
 412                         9  => 'Radio (q = 4.0)',
 413                         10 => 'Standard (q = 5.0)',
 414                         11 => 'Extreme (q = 6.0)',
 415                         12 => 'Insane (q = 7.0)',
 416                         13 => 'BrainDead (q = 8.0)',
 417                         14 => 'above BrainDead (q = 9.0)',
 418                         15 => 'above BrainDead (q = 10.0)'
 419                 );
 420                 return (isset($MPCprofileNameLookup[$profileid]) ? $MPCprofileNameLookup[$profileid] : 'invalid');
 421         }
 422
 423         public function MPCfrequencyLookup($frequencyid) {
 424                 static $MPCfrequencyLookup = array(
 425                         0 => 44100,
 426                         1 => 48000,
 427                         2 => 37800,
 428                         3 => 32000
 429                 );
 430                 return (isset($MPCfrequencyLookup[$frequencyid]) ? $MPCfrequencyLookup[$frequencyid] : 'invalid');
 431         }
 432
 433         public function MPCpeakDBLookup($intvalue) {
 434                 if ($intvalue > 0) {
 435                         return ((log10($intvalue) / log10(2)) - 15) * 6;
 436                 }
 437                 return false;
 438         }
 439
 440         public function MPCencoderVersionLookup($encoderversion) {
 441                 //Encoder version * 100  (106 = 1.06)
 442                 //EncoderVersion % 10 == 0        Release (1.0)
 443                 //EncoderVersion %  2 == 0        Beta (1.06)
 444                 //EncoderVersion %  2 == 1        Alpha (1.05a...z)
 445
 446                 if ($encoderversion == 0) {
 447                         // very old version, not known exactly which
 448                         return 'Buschmann v1.7.0-v1.7.9 or Klemm v0.90-v1.05';
 449                 }
 450
 451                 if (($encoderversion % 10) == 0) {
 452
 453                         // release version
 454                         return number_format($encoderversion / 100, 2);
 455
 456                 } elseif (($encoderversion % 2) == 0) {
 457
 458                         // beta version
 459                         return number_format($encoderversion / 100, 2).' beta';
 460
 461                 }
 462
 463                 // alpha version
 464                 return number_format($encoderversion / 100, 2).' alpha';
 465         }
 466
 467         public function SV8variableLengthInteger($data, &$packetLength, $maxHandledPacketLength=9) {
 468                 $packet_size = 0;
 469                 for ($packetLength = 1; $packetLength <= $maxHandledPacketLength; $packetLength++) {
 470                         // variable-length size field:
 471                         //  bits, big-endian
 472                         //  0xxx xxxx                                           - value 0 to  2^7-1
 473                         //  1xxx xxxx  0xxx xxxx                                - value 0 to 2^14-1
 474                         //  1xxx xxxx  1xxx xxxx  0xxx xxxx                     - value 0 to 2^21-1
 475                         //  1xxx xxxx  1xxx xxxx  1xxx xxxx  0xxx xxxx          - value 0 to 2^28-1
 476                         //  ...
 477                         $thisbyte = ord(substr($data, ($packetLength - 1), 1));
 478                         // look through bytes until find a byte with MSB==0
 479                         $packet_size = ($packet_size << 7);
 480                         $packet_size = ($packet_size | ($thisbyte & 0x7F));
 481                         if (($thisbyte & 0x80) === 0) {
 482                                 break;
 483                         }
 484                         if ($packetLength >= $maxHandledPacketLength) {
 485                                 return false;
 486                         }
 487                 }
 488                 return $packet_size;
 489         }
 490
 491         public function MPCsv8PacketName($packetKey) {
 492                 static $MPCsv8PacketName = array();
 493                 if (empty($MPCsv8PacketName)) {
 494                         $MPCsv8PacketName = array(
 495                                 'AP' => 'Audio Packet',
 496                                 'CT' => 'Chapter Tag',
 497                                 'EI' => 'Encoder Info',
 498                                 'RG' => 'Replay Gain',
 499                                 'SE' => 'Stream End',
 500                                 'SH' => 'Stream Header',
 501                                 'SO' => 'Seek Table Offset',
 502                                 'ST' => 'Seek Table',
 503                         );
 504                 }
 505                 return (isset($MPCsv8PacketName[$packetKey]) ? $MPCsv8PacketName[$packetKey] : $packetKey);
 506         }
 507 }