name : module.audio.mpc.php <?php ///////////////////////////////////////////////////////////////// /// getID3() by James Heinrich <info@getid3.org> // // available at https://github.com/JamesHeinrich/getID3 // // or https://www.getid3.org // // or http://getid3.sourceforge.net // // see readme.txt for more details // ///////////////////////////////////////////////////////////////// // // // module.audio.mpc.php // // module for analyzing Musepack/MPEG+ Audio files // // dependencies: NONE // // /// ///////////////////////////////////////////////////////////////// if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers exit; } class getid3_mpc extends getid3_handler { /** * @return bool */ public function Analyze() { $info = &$this->getid3->info; $info['mpc']['header'] = array(); $thisfile_mpc_header = &$info['mpc']['header']; $info['fileformat'] = 'mpc'; $info['audio']['dataformat'] = 'mpc'; $info['audio']['bitrate_mode'] = 'vbr'; $info['audio']['channels'] = 2; // up to SV7 the format appears to have been hardcoded for stereo only $info['audio']['lossless'] = false; $this->fseek($info['avdataoffset']); $MPCheaderData = $this->fread(4); $info['mpc']['header']['preamble'] = substr($MPCheaderData, 0, 4); // should be 'MPCK' (SV8) or 'MP+' (SV7), otherwise possible stream data (SV4-SV6) if (preg_match('#^MPCK#', $info['mpc']['header']['preamble'])) { // this is SV8 return $this->ParseMPCsv8(); } elseif (preg_match('#^MP\+#', $info['mpc']['header']['preamble'])) { // this is SV7 return $this->ParseMPCsv7(); } 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)) { // this is SV4 - SV6, handle seperately return $this->ParseMPCsv6(); } else { $this->error('Expecting "MP+" or "MPCK" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes(substr($MPCheaderData, 0, 4)).'"'); unset($info['fileformat']); unset($info['mpc']); return false; } } /** * @return bool */ public function ParseMPCsv8() { // this is SV8 // http://trac.musepack.net/trac/wiki/SV8Specification $info = &$this->getid3->info; $thisfile_mpc_header = &$info['mpc']['header']; $keyNameSize = 2; $maxHandledPacketLength = 9; // specs say: "n*8; 0 < n < 10" $offset = $this->ftell(); while ($offset < $info['avdataend']) { $thisPacket = array(); $thisPacket['offset'] = $offset; $packet_offset = 0; // Size is a variable-size field, could be 1-4 bytes (possibly more?) // read enough data in and figure out the exact size later $MPCheaderData = $this->fread($keyNameSize + $maxHandledPacketLength); $packet_offset += $keyNameSize; $thisPacket['key'] = substr($MPCheaderData, 0, $keyNameSize); $thisPacket['key_name'] = $this->MPCsv8PacketName($thisPacket['key']); if ($thisPacket['key'] == $thisPacket['key_name']) { $this->error('Found unexpected key value "'.$thisPacket['key'].'" at offset '.$thisPacket['offset']); return false; } $packetLength = 0; $thisPacket['packet_size'] = $this->SV8variableLengthInteger(substr($MPCheaderData, $keyNameSize), $packetLength); // includes keyname and packet_size field if ($thisPacket['packet_size'] === false) { $this->error('Did not find expected packet length within '.$maxHandledPacketLength.' bytes at offset '.($thisPacket['offset'] + $keyNameSize)); return false; } $packet_offset += $packetLength; $offset += $thisPacket['packet_size']; switch ($thisPacket['key']) { case 'SH': // Stream Header $moreBytesToRead = $thisPacket['packet_size'] - $keyNameSize - $maxHandledPacketLength; if ($moreBytesToRead > 0) { $MPCheaderData .= $this->fread($moreBytesToRead); } $thisPacket['crc'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 4)); $packet_offset += 4; $thisPacket['stream_version'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1)); $packet_offset += 1; $packetLength = 0; $thisPacket['sample_count'] = $this->SV8variableLengthInteger(substr($MPCheaderData, $packet_offset, $maxHandledPacketLength), $packetLength); $packet_offset += $packetLength; $packetLength = 0; $thisPacket['beginning_silence'] = $this->SV8variableLengthInteger(substr($MPCheaderData, $packet_offset, $maxHandledPacketLength), $packetLength); $packet_offset += $packetLength; $otherUsefulData = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2)); $packet_offset += 2; $thisPacket['sample_frequency_raw'] = (($otherUsefulData & 0xE000) >> 13); $thisPacket['max_bands_used'] = (($otherUsefulData & 0x1F00) >> 8); $thisPacket['channels'] = (($otherUsefulData & 0x00F0) >> 4) + 1; $thisPacket['ms_used'] = (bool) (($otherUsefulData & 0x0008) >> 3); $thisPacket['audio_block_frames'] = (($otherUsefulData & 0x0007) >> 0); $thisPacket['sample_frequency'] = $this->MPCfrequencyLookup($thisPacket['sample_frequency_raw']); $thisfile_mpc_header['mid_side_stereo'] = $thisPacket['ms_used']; $thisfile_mpc_header['sample_rate'] = $thisPacket['sample_frequency']; $thisfile_mpc_header['samples'] = $thisPacket['sample_count']; $thisfile_mpc_header['stream_version_major'] = $thisPacket['stream_version']; $info['audio']['channels'] = $thisPacket['channels']; $info['audio']['sample_rate'] = $thisPacket['sample_frequency']; $info['playtime_seconds'] = $thisPacket['sample_count'] / $thisPacket['sample_frequency']; $info['audio']['bitrate'] = getid3_lib::SafeDiv(($info['avdataend'] - $info['avdataoffset']) * 8, $info['playtime_seconds']); break; case 'RG': // Replay Gain $moreBytesToRead = $thisPacket['packet_size'] - $keyNameSize - $maxHandledPacketLength; if ($moreBytesToRead > 0) { $MPCheaderData .= $this->fread($moreBytesToRead); } $thisPacket['replaygain_version'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1)); $packet_offset += 1; $thisPacket['replaygain_title_gain'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2)); $packet_offset += 2; $thisPacket['replaygain_title_peak'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2)); $packet_offset += 2; $thisPacket['replaygain_album_gain'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2)); $packet_offset += 2; $thisPacket['replaygain_album_peak'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 2)); $packet_offset += 2; if ($thisPacket['replaygain_title_gain']) { $info['replay_gain']['title']['gain'] = $thisPacket['replaygain_title_gain']; } if ($thisPacket['replaygain_title_peak']) { $info['replay_gain']['title']['peak'] = $thisPacket['replaygain_title_peak']; } if ($thisPacket['replaygain_album_gain']) { $info['replay_gain']['album']['gain'] = $thisPacket['replaygain_album_gain']; } if ($thisPacket['replaygain_album_peak']) { $info['replay_gain']['album']['peak'] = $thisPacket['replaygain_album_peak']; } break; case 'EI': // Encoder Info $moreBytesToRead = $thisPacket['packet_size'] - $keyNameSize - $maxHandledPacketLength; if ($moreBytesToRead > 0) { $MPCheaderData .= $this->fread($moreBytesToRead); } $profile_pns = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1)); $packet_offset += 1; $quality_int = (($profile_pns & 0xF0) >> 4); $quality_dec = (($profile_pns & 0x0E) >> 3); $thisPacket['quality'] = (float) $quality_int + ($quality_dec / 8); $thisPacket['pns_tool'] = (bool) (($profile_pns & 0x01) >> 0); $thisPacket['version_major'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1)); $packet_offset += 1; $thisPacket['version_minor'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1)); $packet_offset += 1; $thisPacket['version_build'] = getid3_lib::BigEndian2Int(substr($MPCheaderData, $packet_offset, 1)); $packet_offset += 1; $thisPacket['version'] = $thisPacket['version_major'].'.'.$thisPacket['version_minor'].'.'.$thisPacket['version_build']; $info['audio']['encoder'] = 'MPC v'.$thisPacket['version'].' ('.(($thisPacket['version_minor'] % 2) ? 'unstable' : 'stable').')'; $thisfile_mpc_header['encoder_version'] = $info['audio']['encoder']; //$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 $thisfile_mpc_header['quality'] = (float) ($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 break; case 'SO': // Seek Table Offset $packetLength = 0; $thisPacket['seek_table_offset'] = $thisPacket['offset'] + $this->SV8variableLengthInteger(substr($MPCheaderData, $packet_offset, $maxHandledPacketLength), $packetLength); $packet_offset += $packetLength; break; case 'ST': // Seek Table case 'SE': // Stream End case 'AP': // Audio Data // nothing useful here, just skip this packet $thisPacket = array(); break; default: $this->error('Found unhandled key type "'.$thisPacket['key'].'" at offset '.$thisPacket['offset']); return false; } if (!empty($thisPacket)) { $info['mpc']['packets'][] = $thisPacket; } $this->fseek($offset); } $thisfile_mpc_header['size'] = $offset; return true; } /** * @return bool */ public function ParseMPCsv7() { // this is SV7 // http://www.uni-jena.de/~pfk/mpp/sv8/header.html $info = &$this->getid3->info; $thisfile_mpc_header = &$info['mpc']['header']; $offset = 0; $thisfile_mpc_header['size'] = 28; $MPCheaderData = $info['mpc']['header']['preamble']; $MPCheaderData .= $this->fread($thisfile_mpc_header['size'] - strlen($info['mpc']['header']['preamble'])); $offset = strlen('MP+'); $StreamVersionByte = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 1)); $offset += 1; $thisfile_mpc_header['stream_version_major'] = ($StreamVersionByte & 0x0F) >> 0; $thisfile_mpc_header['stream_version_minor'] = ($StreamVersionByte & 0xF0) >> 4; // should always be 0, subversions no longer exist in SV8 $thisfile_mpc_header['frame_count'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 4)); $offset += 4; if ($thisfile_mpc_header['stream_version_major'] != 7) { $this->error('Only Musepack SV7 supported (this file claims to be v'.$thisfile_mpc_header['stream_version_major'].')'); return false; } $FlagsDWORD1 = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 4)); $offset += 4; $thisfile_mpc_header['intensity_stereo'] = (bool) (($FlagsDWORD1 & 0x80000000) >> 31); $thisfile_mpc_header['mid_side_stereo'] = (bool) (($FlagsDWORD1 & 0x40000000) >> 30); $thisfile_mpc_header['max_subband'] = ($FlagsDWORD1 & 0x3F000000) >> 24; $thisfile_mpc_header['raw']['profile'] = ($FlagsDWORD1 & 0x00F00000) >> 20; $thisfile_mpc_header['begin_loud'] = (bool) (($FlagsDWORD1 & 0x00080000) >> 19); $thisfile_mpc_header['end_loud'] = (bool) (($FlagsDWORD1 & 0x00040000) >> 18); $thisfile_mpc_header['raw']['sample_rate'] = ($FlagsDWORD1 & 0x00030000) >> 16; $thisfile_mpc_header['max_level'] = ($FlagsDWORD1 & 0x0000FFFF); $thisfile_mpc_header['raw']['title_peak'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2)); $offset += 2; $thisfile_mpc_header['raw']['title_gain'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2), true); $offset += 2; $thisfile_mpc_header['raw']['album_peak'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2)); $offset += 2; $thisfile_mpc_header['raw']['album_gain'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 2), true); $offset += 2; $FlagsDWORD2 = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 4)); $offset += 4; $thisfile_mpc_header['true_gapless'] = (bool) (($FlagsDWORD2 & 0x80000000) >> 31); $thisfile_mpc_header['last_frame_length'] = ($FlagsDWORD2 & 0x7FF00000) >> 20; $thisfile_mpc_header['raw']['not_sure_what'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 3)); $offset += 3; $thisfile_mpc_header['raw']['encoder_version'] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, $offset, 1)); $offset += 1; $thisfile_mpc_header['profile'] = $this->MPCprofileNameLookup($thisfile_mpc_header['raw']['profile']); $thisfile_mpc_header['sample_rate'] = $this->MPCfrequencyLookup($thisfile_mpc_header['raw']['sample_rate']); if ($thisfile_mpc_header['sample_rate'] == 0) { $this->error('Corrupt MPC file: frequency == zero'); return false; } $info['audio']['sample_rate'] = $thisfile_mpc_header['sample_rate']; $thisfile_mpc_header['samples'] = ((($thisfile_mpc_header['frame_count'] - 1) * 1152) + $thisfile_mpc_header['last_frame_length']) * $info['audio']['channels']; $info['playtime_seconds'] = getid3_lib::SafeDiv($thisfile_mpc_header['samples'], $info['audio']['channels'] * $info['audio']['sample_rate']); if ($info['playtime_seconds'] == 0) { $this->error('Corrupt MPC file: playtime_seconds == zero'); return false; } // add size of file header to avdataoffset - calc bitrate correctly + MD5 data $info['avdataoffset'] += $thisfile_mpc_header['size']; $info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds']; $thisfile_mpc_header['title_peak'] = $thisfile_mpc_header['raw']['title_peak']; $thisfile_mpc_header['title_peak_db'] = $this->MPCpeakDBLookup($thisfile_mpc_header['title_peak']); if ($thisfile_mpc_header['raw']['title_gain'] < 0) { $thisfile_mpc_header['title_gain_db'] = (float) (32768 + $thisfile_mpc_header['raw']['title_gain']) / -100; } else { $thisfile_mpc_header['title_gain_db'] = (float) $thisfile_mpc_header['raw']['title_gain'] / 100; } $thisfile_mpc_header['album_peak'] = $thisfile_mpc_header['raw']['album_peak']; $thisfile_mpc_header['album_peak_db'] = $this->MPCpeakDBLookup($thisfile_mpc_header['album_peak']); if ($thisfile_mpc_header['raw']['album_gain'] < 0) { $thisfile_mpc_header['album_gain_db'] = (float) (32768 + $thisfile_mpc_header['raw']['album_gain']) / -100; } else { $thisfile_mpc_header['album_gain_db'] = (float) $thisfile_mpc_header['raw']['album_gain'] / 100;; } $thisfile_mpc_header['encoder_version'] = $this->MPCencoderVersionLookup($thisfile_mpc_header['raw']['encoder_version']); $info['replay_gain']['track']['adjustment'] = $thisfile_mpc_header['title_gain_db']; $info['replay_gain']['album']['adjustment'] = $thisfile_mpc_header['album_gain_db']; if ($thisfile_mpc_header['title_peak'] > 0) { $info['replay_gain']['track']['peak'] = $thisfile_mpc_header['title_peak']; } elseif (round($thisfile_mpc_header['max_level'] * 1.18) > 0) { $info['replay_gain']['track']['peak'] = getid3_lib::CastAsInt(round($thisfile_mpc_header['max_level'] * 1.18)); // why? I don't know - see mppdec.c } if ($thisfile_mpc_header['album_peak'] > 0) { $info['replay_gain']['album']['peak'] = $thisfile_mpc_header['album_peak']; } //$info['audio']['encoder'] = 'SV'.$thisfile_mpc_header['stream_version_major'].'.'.$thisfile_mpc_header['stream_version_minor'].', '.$thisfile_mpc_header['encoder_version']; $info['audio']['encoder'] = $thisfile_mpc_header['encoder_version']; $info['audio']['encoder_options'] = $thisfile_mpc_header['profile']; $thisfile_mpc_header['quality'] = (float) ($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 return true; } /** * @return bool */ public function ParseMPCsv6() { // this is SV4 - SV6 $info = &$this->getid3->info; $thisfile_mpc_header = &$info['mpc']['header']; $offset = 0; $thisfile_mpc_header['size'] = 8; $this->fseek($info['avdataoffset']); $MPCheaderData = $this->fread($thisfile_mpc_header['size']); // add size of file header to avdataoffset - calc bitrate correctly + MD5 data $info['avdataoffset'] += $thisfile_mpc_header['size']; // Most of this code adapted from Jurgen Faul's MPEGplus source code - thanks Jurgen! :) $HeaderDWORD = array(); $HeaderDWORD[0] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, 0, 4)); $HeaderDWORD[1] = getid3_lib::LittleEndian2Int(substr($MPCheaderData, 4, 4)); // DDDD DDDD CCCC CCCC BBBB BBBB AAAA AAAA // aaaa aaaa abcd dddd dddd deee eeff ffff // // a = bitrate = anything // b = IS = anything // c = MS = anything // d = streamversion = 0000000004 or 0000000005 or 0000000006 // e = maxband = anything // f = blocksize = 000001 for SV5+, anything(?) for SV4 $thisfile_mpc_header['target_bitrate'] = (($HeaderDWORD[0] & 0xFF800000) >> 23); $thisfile_mpc_header['intensity_stereo'] = (bool) (($HeaderDWORD[0] & 0x00400000) >> 22); $thisfile_mpc_header['mid_side_stereo'] = (bool) (($HeaderDWORD[0] & 0x00200000) >> 21); $thisfile_mpc_header['stream_version_major'] = ($HeaderDWORD[0] & 0x001FF800) >> 11; $thisfile_mpc_header['stream_version_minor'] = 0; // no sub-version numbers before SV7 $thisfile_mpc_header['max_band'] = ($HeaderDWORD[0] & 0x000007C0) >> 6; // related to lowpass frequency, not sure how it translates exactly $thisfile_mpc_header['block_size'] = ($HeaderDWORD[0] & 0x0000003F); switch ($thisfile_mpc_header['stream_version_major']) { case 4: $thisfile_mpc_header['frame_count'] = ($HeaderDWORD[1] >> 16); break; case 5: case 6: $thisfile_mpc_header['frame_count'] = $HeaderDWORD[1]; break; default: $info['error'] = 'Expecting 4, 5 or 6 in version field, found '.$thisfile_mpc_header['stream_version_major'].' instead'; unset($info['mpc']); return false; } if (($thisfile_mpc_header['stream_version_major'] > 4) && ($thisfile_mpc_header['block_size'] != 1)) { $this->warning('Block size expected to be 1, actual value found: '.$thisfile_mpc_header['block_size']); } $thisfile_mpc_header['sample_rate'] = 44100; // AB: used by all files up to SV7 $info['audio']['sample_rate'] = $thisfile_mpc_header['sample_rate']; $thisfile_mpc_header['samples'] = $thisfile_mpc_header['frame_count'] * 1152 * $info['audio']['channels']; if ($thisfile_mpc_header['target_bitrate'] == 0) { $info['audio']['bitrate_mode'] = 'vbr'; } else { $info['audio']['bitrate_mode'] = 'cbr'; } $info['mpc']['bitrate'] = ($info['avdataend'] - $info['avdataoffset']) * 8 * 44100 / $thisfile_mpc_header['frame_count'] / 1152; $info['audio']['bitrate'] = $info['mpc']['bitrate']; $info['audio']['encoder'] = 'SV'.$thisfile_mpc_header['stream_version_major']; return true; } /** * @param int $profileid * * @return string */ public function MPCprofileNameLookup($profileid) { static $MPCprofileNameLookup = array( 0 => 'no profile', 1 => 'Experimental', 2 => 'unused', 3 => 'unused', 4 => 'unused', 5 => 'below Telephone (q = 0.0)', 6 => 'below Telephone (q = 1.0)', 7 => 'Telephone (q = 2.0)', 8 => 'Thumb (q = 3.0)', 9 => 'Radio (q = 4.0)', 10 => 'Standard (q = 5.0)', 11 => 'Extreme (q = 6.0)', 12 => 'Insane (q = 7.0)', 13 => 'BrainDead (q = 8.0)', 14 => 'above BrainDead (q = 9.0)', 15 => 'above BrainDead (q = 10.0)' ); return (isset($MPCprofileNameLookup[$profileid]) ? $MPCprofileNameLookup[$profileid] : 'invalid'); } /** * @param int $frequencyid * * @return int|string */ public function MPCfrequencyLookup($frequencyid) { static $MPCfrequencyLookup = array( 0 => 44100, 1 => 48000, 2 => 37800, 3 => 32000 ); return (isset($MPCfrequencyLookup[$frequencyid]) ? $MPCfrequencyLookup[$frequencyid] : 'invalid'); } /** * @param int $intvalue * * @return float|false */ public function MPCpeakDBLookup($intvalue) { if ($intvalue > 0) { return ((log10($intvalue) / log10(2)) - 15) * 6; } return false; } /** * @param int $encoderversion * * @return string */ public function MPCencoderVersionLookup($encoderversion) { //Encoder version * 100 (106 = 1.06) //EncoderVersion % 10 == 0 Release (1.0) //EncoderVersion % 2 == 0 Beta (1.06) //EncoderVersion % 2 == 1 Alpha (1.05a...z) if ($encoderversion == 0) { // very old version, not known exactly which return 'Buschmann v1.7.0-v1.7.9 or Klemm v0.90-v1.05'; } if (($encoderversion % 10) == 0) { // release version return number_format($encoderversion / 100, 2); } elseif (($encoderversion % 2) == 0) { // beta version return number_format($encoderversion / 100, 2).' beta'; } // alpha version return number_format($encoderversion / 100, 2).' alpha'; } /** * @param string $data * @param int $packetLength * @param int $maxHandledPacketLength * * @return int|false */ public function SV8variableLengthInteger($data, &$packetLength, $maxHandledPacketLength=9) { $packet_size = 0; for ($packetLength = 1; $packetLength <= $maxHandledPacketLength; $packetLength++) { // variable-length size field: // bits, big-endian // 0xxx xxxx - value 0 to 2^7-1 // 1xxx xxxx 0xxx xxxx - value 0 to 2^14-1 // 1xxx xxxx 1xxx xxxx 0xxx xxxx - value 0 to 2^21-1 // 1xxx xxxx 1xxx xxxx 1xxx xxxx 0xxx xxxx - value 0 to 2^28-1 // ... $thisbyte = ord(substr($data, ($packetLength - 1), 1)); // look through bytes until find a byte with MSB==0 $packet_size = ($packet_size << 7); $packet_size = ($packet_size | ($thisbyte & 0x7F)); if (($thisbyte & 0x80) === 0) { break; } if ($packetLength >= $maxHandledPacketLength) { return false; } } return $packet_size; } /** * @param string $packetKey * * @return string */ public function MPCsv8PacketName($packetKey) { static $MPCsv8PacketName = array(); if (empty($MPCsv8PacketName)) { $MPCsv8PacketName = array( 'AP' => 'Audio Packet', 'CT' => 'Chapter Tag', 'EI' => 'Encoder Info', 'RG' => 'Replay Gain', 'SE' => 'Stream End', 'SH' => 'Stream Header', 'SO' => 'Seek Table Offset', 'ST' => 'Seek Table', ); } return (isset($MPCsv8PacketName[$packetKey]) ? $MPCsv8PacketName[$packetKey] : $packetKey); } }