name : module.audio.ac3.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.ac3.php // // module for analyzing AC-3 (aka Dolby Digital) audio files // // dependencies: NONE // // /// ///////////////////////////////////////////////////////////////// if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers exit; } class getid3_ac3 extends getid3_handler { /** * @var array */ private $AC3header = array(); /** * @var int */ private $BSIoffset = 0; const syncword = 0x0B77; /** * @return bool */ public function Analyze() { $info = &$this->getid3->info; ///AH $info['ac3']['raw']['bsi'] = array(); $thisfile_ac3 = &$info['ac3']; $thisfile_ac3_raw = &$thisfile_ac3['raw']; $thisfile_ac3_raw_bsi = &$thisfile_ac3_raw['bsi']; // http://www.atsc.org/standards/a_52a.pdf $info['fileformat'] = 'ac3'; // An AC-3 serial coded audio bit stream is made up of a sequence of synchronization frames // Each synchronization frame contains 6 coded audio blocks (AB), each of which represent 256 // new audio samples per channel. A synchronization information (SI) header at the beginning // of each frame contains information needed to acquire and maintain synchronization. A // bit stream information (BSI) header follows SI, and contains parameters describing the coded // audio service. The coded audio blocks may be followed by an auxiliary data (Aux) field. At the // end of each frame is an error check field that includes a CRC word for error detection. An // additional CRC word is located in the SI header, the use of which, by a decoder, is optional. // // syncinfo() | bsi() | AB0 | AB1 | AB2 | AB3 | AB4 | AB5 | Aux | CRC // syncinfo() { // syncword 16 // crc1 16 // fscod 2 // frmsizecod 6 // } /* end of syncinfo */ $this->fseek($info['avdataoffset']); $tempAC3header = $this->fread(100); // should be enough to cover all data, there are some variable-length fields...? $this->AC3header['syncinfo'] = getid3_lib::BigEndian2Int(substr($tempAC3header, 0, 2)); $this->AC3header['bsi'] = getid3_lib::BigEndian2Bin(substr($tempAC3header, 2)); $thisfile_ac3_raw_bsi['bsid'] = (getid3_lib::LittleEndian2Int(substr($tempAC3header, 5, 1)) & 0xF8) >> 3; // AC3 and E-AC3 put the "bsid" version identifier in the same place, but unfortnately the 4 bytes between the syncword and the version identifier are interpreted differently, so grab it here so the following code structure can make sense unset($tempAC3header); if ($this->AC3header['syncinfo'] !== self::syncword) { if (!$this->isDependencyFor('matroska')) { unset($info['fileformat'], $info['ac3']); return $this->error('Expecting "'.dechex(self::syncword).'" at offset '.$info['avdataoffset'].', found "'.dechex($this->AC3header['syncinfo']).'"'); } } $info['audio']['dataformat'] = 'ac3'; $info['audio']['bitrate_mode'] = 'cbr'; $info['audio']['lossless'] = false; if ($thisfile_ac3_raw_bsi['bsid'] <= 8) { $thisfile_ac3_raw_bsi['crc1'] = getid3_lib::Bin2Dec($this->readHeaderBSI(16)); $thisfile_ac3_raw_bsi['fscod'] = $this->readHeaderBSI(2); // 5.4.1.3 $thisfile_ac3_raw_bsi['frmsizecod'] = $this->readHeaderBSI(6); // 5.4.1.4 if ($thisfile_ac3_raw_bsi['frmsizecod'] > 37) { // binary: 100101 - see Table 5.18 Frame Size Code Table (1 word = 16 bits) $this->warning('Unexpected ac3.bsi.frmsizecod value: '.$thisfile_ac3_raw_bsi['frmsizecod'].', bitrate not set correctly'); } $thisfile_ac3_raw_bsi['bsid'] = $this->readHeaderBSI(5); // we already know this from pre-parsing the version identifier, but re-read it to let the bitstream flow as intended $thisfile_ac3_raw_bsi['bsmod'] = $this->readHeaderBSI(3); $thisfile_ac3_raw_bsi['acmod'] = $this->readHeaderBSI(3); if ($thisfile_ac3_raw_bsi['acmod'] & 0x01) { // If the lsb of acmod is a 1, center channel is in use and cmixlev follows in the bit stream. $thisfile_ac3_raw_bsi['cmixlev'] = $this->readHeaderBSI(2); $thisfile_ac3['center_mix_level'] = self::centerMixLevelLookup($thisfile_ac3_raw_bsi['cmixlev']); } if ($thisfile_ac3_raw_bsi['acmod'] & 0x04) { // If the msb of acmod is a 1, surround channels are in use and surmixlev follows in the bit stream. $thisfile_ac3_raw_bsi['surmixlev'] = $this->readHeaderBSI(2); $thisfile_ac3['surround_mix_level'] = self::surroundMixLevelLookup($thisfile_ac3_raw_bsi['surmixlev']); } if ($thisfile_ac3_raw_bsi['acmod'] == 0x02) { // When operating in the two channel mode, this 2-bit code indicates whether or not the program has been encoded in Dolby Surround. $thisfile_ac3_raw_bsi['dsurmod'] = $this->readHeaderBSI(2); $thisfile_ac3['dolby_surround_mode'] = self::dolbySurroundModeLookup($thisfile_ac3_raw_bsi['dsurmod']); } $thisfile_ac3_raw_bsi['flags']['lfeon'] = (bool) $this->readHeaderBSI(1); // This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1-31. // The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent. $thisfile_ac3_raw_bsi['dialnorm'] = $this->readHeaderBSI(5); // 5.4.2.8 dialnorm: Dialogue Normalization, 5 Bits $thisfile_ac3_raw_bsi['flags']['compr'] = (bool) $this->readHeaderBSI(1); // 5.4.2.9 compre: Compression Gain Word Exists, 1 Bit if ($thisfile_ac3_raw_bsi['flags']['compr']) { $thisfile_ac3_raw_bsi['compr'] = $this->readHeaderBSI(8); // 5.4.2.10 compr: Compression Gain Word, 8 Bits $thisfile_ac3['heavy_compression'] = self::heavyCompression($thisfile_ac3_raw_bsi['compr']); } $thisfile_ac3_raw_bsi['flags']['langcod'] = (bool) $this->readHeaderBSI(1); // 5.4.2.11 langcode: Language Code Exists, 1 Bit if ($thisfile_ac3_raw_bsi['flags']['langcod']) { $thisfile_ac3_raw_bsi['langcod'] = $this->readHeaderBSI(8); // 5.4.2.12 langcod: Language Code, 8 Bits } $thisfile_ac3_raw_bsi['flags']['audprodinfo'] = (bool) $this->readHeaderBSI(1); // 5.4.2.13 audprodie: Audio Production Information Exists, 1 Bit if ($thisfile_ac3_raw_bsi['flags']['audprodinfo']) { $thisfile_ac3_raw_bsi['mixlevel'] = $this->readHeaderBSI(5); // 5.4.2.14 mixlevel: Mixing Level, 5 Bits $thisfile_ac3_raw_bsi['roomtyp'] = $this->readHeaderBSI(2); // 5.4.2.15 roomtyp: Room Type, 2 Bits $thisfile_ac3['mixing_level'] = (80 + $thisfile_ac3_raw_bsi['mixlevel']).'dB'; $thisfile_ac3['room_type'] = self::roomTypeLookup($thisfile_ac3_raw_bsi['roomtyp']); } $thisfile_ac3_raw_bsi['dialnorm2'] = $this->readHeaderBSI(5); // 5.4.2.16 dialnorm2: Dialogue Normalization, ch2, 5 Bits $thisfile_ac3['dialogue_normalization2'] = '-'.$thisfile_ac3_raw_bsi['dialnorm2'].'dB'; // This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1-31. The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent. $thisfile_ac3_raw_bsi['flags']['compr2'] = (bool) $this->readHeaderBSI(1); // 5.4.2.17 compr2e: Compression Gain Word Exists, ch2, 1 Bit if ($thisfile_ac3_raw_bsi['flags']['compr2']) { $thisfile_ac3_raw_bsi['compr2'] = $this->readHeaderBSI(8); // 5.4.2.18 compr2: Compression Gain Word, ch2, 8 Bits $thisfile_ac3['heavy_compression2'] = self::heavyCompression($thisfile_ac3_raw_bsi['compr2']); } $thisfile_ac3_raw_bsi['flags']['langcod2'] = (bool) $this->readHeaderBSI(1); // 5.4.2.19 langcod2e: Language Code Exists, ch2, 1 Bit if ($thisfile_ac3_raw_bsi['flags']['langcod2']) { $thisfile_ac3_raw_bsi['langcod2'] = $this->readHeaderBSI(8); // 5.4.2.20 langcod2: Language Code, ch2, 8 Bits } $thisfile_ac3_raw_bsi['flags']['audprodinfo2'] = (bool) $this->readHeaderBSI(1); // 5.4.2.21 audprodi2e: Audio Production Information Exists, ch2, 1 Bit if ($thisfile_ac3_raw_bsi['flags']['audprodinfo2']) { $thisfile_ac3_raw_bsi['mixlevel2'] = $this->readHeaderBSI(5); // 5.4.2.22 mixlevel2: Mixing Level, ch2, 5 Bits $thisfile_ac3_raw_bsi['roomtyp2'] = $this->readHeaderBSI(2); // 5.4.2.23 roomtyp2: Room Type, ch2, 2 Bits $thisfile_ac3['mixing_level2'] = (80 + $thisfile_ac3_raw_bsi['mixlevel2']).'dB'; $thisfile_ac3['room_type2'] = self::roomTypeLookup($thisfile_ac3_raw_bsi['roomtyp2']); } $thisfile_ac3_raw_bsi['copyright'] = (bool) $this->readHeaderBSI(1); // 5.4.2.24 copyrightb: Copyright Bit, 1 Bit $thisfile_ac3_raw_bsi['original'] = (bool) $this->readHeaderBSI(1); // 5.4.2.25 origbs: Original Bit Stream, 1 Bit $thisfile_ac3_raw_bsi['flags']['timecod1'] = $this->readHeaderBSI(2); // 5.4.2.26 timecod1e, timcode2e: Time Code (first and second) Halves Exist, 2 Bits if ($thisfile_ac3_raw_bsi['flags']['timecod1'] & 0x01) { $thisfile_ac3_raw_bsi['timecod1'] = $this->readHeaderBSI(14); // 5.4.2.27 timecod1: Time code first half, 14 bits $thisfile_ac3['timecode1'] = 0; $thisfile_ac3['timecode1'] += (($thisfile_ac3_raw_bsi['timecod1'] & 0x3E00) >> 9) * 3600; // The first 5 bits of this 14-bit field represent the time in hours, with valid values of 0�23 $thisfile_ac3['timecode1'] += (($thisfile_ac3_raw_bsi['timecod1'] & 0x01F8) >> 3) * 60; // The next 6 bits represent the time in minutes, with valid values of 0�59 $thisfile_ac3['timecode1'] += (($thisfile_ac3_raw_bsi['timecod1'] & 0x0003) >> 0) * 8; // The final 3 bits represents the time in 8 second increments, with valid values of 0�7 (representing 0, 8, 16, ... 56 seconds) } if ($thisfile_ac3_raw_bsi['flags']['timecod1'] & 0x02) { $thisfile_ac3_raw_bsi['timecod2'] = $this->readHeaderBSI(14); // 5.4.2.28 timecod2: Time code second half, 14 bits $thisfile_ac3['timecode2'] = 0; $thisfile_ac3['timecode2'] += (($thisfile_ac3_raw_bsi['timecod2'] & 0x3800) >> 11) * 1; // The first 3 bits of this 14-bit field represent the time in seconds, with valid values from 0�7 (representing 0-7 seconds) $thisfile_ac3['timecode2'] += (($thisfile_ac3_raw_bsi['timecod2'] & 0x07C0) >> 6) * (1 / 30); // The next 5 bits represents the time in frames, with valid values from 0�29 (one frame = 1/30th of a second) $thisfile_ac3['timecode2'] += (($thisfile_ac3_raw_bsi['timecod2'] & 0x003F) >> 0) * ((1 / 30) / 60); // The final 6 bits represents fractions of 1/64 of a frame, with valid values from 0�63 } $thisfile_ac3_raw_bsi['flags']['addbsi'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['addbsi']) { $thisfile_ac3_raw_bsi['addbsi_length'] = $this->readHeaderBSI(6) + 1; // This 6-bit code, which exists only if addbside is a 1, indicates the length in bytes of additional bit stream information. The valid range of addbsil is 0�63, indicating 1�64 additional bytes, respectively. $this->AC3header['bsi'] .= getid3_lib::BigEndian2Bin($this->fread($thisfile_ac3_raw_bsi['addbsi_length'])); $thisfile_ac3_raw_bsi['addbsi_data'] = substr($this->AC3header['bsi'], $this->BSIoffset, $thisfile_ac3_raw_bsi['addbsi_length'] * 8); $this->BSIoffset += $thisfile_ac3_raw_bsi['addbsi_length'] * 8; } } elseif ($thisfile_ac3_raw_bsi['bsid'] <= 16) { // E-AC3 $this->error('E-AC3 parsing is incomplete and experimental in this version of getID3 ('.$this->getid3->version().'). Notably the bitrate calculations are wrong -- value might (or not) be correct, but it is not calculated correctly. Email info@getid3.org if you know how to calculate EAC3 bitrate correctly.'); $info['audio']['dataformat'] = 'eac3'; $thisfile_ac3_raw_bsi['strmtyp'] = $this->readHeaderBSI(2); $thisfile_ac3_raw_bsi['substreamid'] = $this->readHeaderBSI(3); $thisfile_ac3_raw_bsi['frmsiz'] = $this->readHeaderBSI(11); $thisfile_ac3_raw_bsi['fscod'] = $this->readHeaderBSI(2); if ($thisfile_ac3_raw_bsi['fscod'] == 3) { $thisfile_ac3_raw_bsi['fscod2'] = $this->readHeaderBSI(2); $thisfile_ac3_raw_bsi['numblkscod'] = 3; // six blocks per syncframe } else { $thisfile_ac3_raw_bsi['numblkscod'] = $this->readHeaderBSI(2); } $thisfile_ac3['bsi']['blocks_per_sync_frame'] = self::blocksPerSyncFrame($thisfile_ac3_raw_bsi['numblkscod']); $thisfile_ac3_raw_bsi['acmod'] = $this->readHeaderBSI(3); $thisfile_ac3_raw_bsi['flags']['lfeon'] = (bool) $this->readHeaderBSI(1); $thisfile_ac3_raw_bsi['bsid'] = $this->readHeaderBSI(5); // we already know this from pre-parsing the version identifier, but re-read it to let the bitstream flow as intended $thisfile_ac3_raw_bsi['dialnorm'] = $this->readHeaderBSI(5); $thisfile_ac3_raw_bsi['flags']['compr'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['compr']) { $thisfile_ac3_raw_bsi['compr'] = $this->readHeaderBSI(8); } if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value) $thisfile_ac3_raw_bsi['dialnorm2'] = $this->readHeaderBSI(5); $thisfile_ac3_raw_bsi['flags']['compr2'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['compr2']) { $thisfile_ac3_raw_bsi['compr2'] = $this->readHeaderBSI(8); } } if ($thisfile_ac3_raw_bsi['strmtyp'] == 1) { // if dependent stream $thisfile_ac3_raw_bsi['flags']['chanmap'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['chanmap']) { $thisfile_ac3_raw_bsi['chanmap'] = $this->readHeaderBSI(8); } } $thisfile_ac3_raw_bsi['flags']['mixmdat'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['mixmdat']) { // Mixing metadata if ($thisfile_ac3_raw_bsi['acmod'] > 2) { // if more than 2 channels $thisfile_ac3_raw_bsi['dmixmod'] = $this->readHeaderBSI(2); } if (($thisfile_ac3_raw_bsi['acmod'] & 0x01) && ($thisfile_ac3_raw_bsi['acmod'] > 2)) { // if three front channels exist $thisfile_ac3_raw_bsi['ltrtcmixlev'] = $this->readHeaderBSI(3); $thisfile_ac3_raw_bsi['lorocmixlev'] = $this->readHeaderBSI(3); } if ($thisfile_ac3_raw_bsi['acmod'] & 0x04) { // if a surround channel exists $thisfile_ac3_raw_bsi['ltrtsurmixlev'] = $this->readHeaderBSI(3); $thisfile_ac3_raw_bsi['lorosurmixlev'] = $this->readHeaderBSI(3); } if ($thisfile_ac3_raw_bsi['flags']['lfeon']) { // if the LFE channel exists $thisfile_ac3_raw_bsi['flags']['lfemixlevcod'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['lfemixlevcod']) { $thisfile_ac3_raw_bsi['lfemixlevcod'] = $this->readHeaderBSI(5); } } if ($thisfile_ac3_raw_bsi['strmtyp'] == 0) { // if independent stream $thisfile_ac3_raw_bsi['flags']['pgmscl'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['pgmscl']) { $thisfile_ac3_raw_bsi['pgmscl'] = $this->readHeaderBSI(6); } if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value) $thisfile_ac3_raw_bsi['flags']['pgmscl2'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['pgmscl2']) { $thisfile_ac3_raw_bsi['pgmscl2'] = $this->readHeaderBSI(6); } } $thisfile_ac3_raw_bsi['flags']['extpgmscl'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['extpgmscl']) { $thisfile_ac3_raw_bsi['extpgmscl'] = $this->readHeaderBSI(6); } $thisfile_ac3_raw_bsi['mixdef'] = $this->readHeaderBSI(2); if ($thisfile_ac3_raw_bsi['mixdef'] == 1) { // mixing option 2 $thisfile_ac3_raw_bsi['premixcmpsel'] = (bool) $this->readHeaderBSI(1); $thisfile_ac3_raw_bsi['drcsrc'] = (bool) $this->readHeaderBSI(1); $thisfile_ac3_raw_bsi['premixcmpscl'] = $this->readHeaderBSI(3); } elseif ($thisfile_ac3_raw_bsi['mixdef'] == 2) { // mixing option 3 $thisfile_ac3_raw_bsi['mixdata'] = $this->readHeaderBSI(12); } elseif ($thisfile_ac3_raw_bsi['mixdef'] == 3) { // mixing option 4 $mixdefbitsread = 0; $thisfile_ac3_raw_bsi['mixdeflen'] = $this->readHeaderBSI(5); $mixdefbitsread += 5; $thisfile_ac3_raw_bsi['flags']['mixdata2'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['mixdata2']) { $thisfile_ac3_raw_bsi['premixcmpsel'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; $thisfile_ac3_raw_bsi['drcsrc'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; $thisfile_ac3_raw_bsi['premixcmpscl'] = $this->readHeaderBSI(3); $mixdefbitsread += 3; $thisfile_ac3_raw_bsi['flags']['extpgmlscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmlscl']) { $thisfile_ac3_raw_bsi['extpgmlscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } $thisfile_ac3_raw_bsi['flags']['extpgmcscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmcscl']) { $thisfile_ac3_raw_bsi['extpgmcscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } $thisfile_ac3_raw_bsi['flags']['extpgmrscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmrscl']) { $thisfile_ac3_raw_bsi['extpgmrscl'] = $this->readHeaderBSI(4); } $thisfile_ac3_raw_bsi['flags']['extpgmlsscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmlsscl']) { $thisfile_ac3_raw_bsi['extpgmlsscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } $thisfile_ac3_raw_bsi['flags']['extpgmrsscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmrsscl']) { $thisfile_ac3_raw_bsi['extpgmrsscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } $thisfile_ac3_raw_bsi['flags']['extpgmlfescl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmlfescl']) { $thisfile_ac3_raw_bsi['extpgmlfescl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } $thisfile_ac3_raw_bsi['flags']['dmixscl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['dmixscl']) { $thisfile_ac3_raw_bsi['dmixscl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } $thisfile_ac3_raw_bsi['flags']['addch'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['addch']) { $thisfile_ac3_raw_bsi['flags']['extpgmaux1scl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmaux1scl']) { $thisfile_ac3_raw_bsi['extpgmaux1scl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } $thisfile_ac3_raw_bsi['flags']['extpgmaux2scl'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['extpgmaux2scl']) { $thisfile_ac3_raw_bsi['extpgmaux2scl'] = $this->readHeaderBSI(4); $mixdefbitsread += 4; } } } $thisfile_ac3_raw_bsi['flags']['mixdata3'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['mixdata3']) { $thisfile_ac3_raw_bsi['spchdat'] = $this->readHeaderBSI(5); $mixdefbitsread += 5; $thisfile_ac3_raw_bsi['flags']['addspchdat'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['addspchdat']) { $thisfile_ac3_raw_bsi['spchdat1'] = $this->readHeaderBSI(5); $mixdefbitsread += 5; $thisfile_ac3_raw_bsi['spchan1att'] = $this->readHeaderBSI(2); $mixdefbitsread += 2; $thisfile_ac3_raw_bsi['flags']['addspchdat1'] = (bool) $this->readHeaderBSI(1); $mixdefbitsread += 1; if ($thisfile_ac3_raw_bsi['flags']['addspchdat1']) { $thisfile_ac3_raw_bsi['spchdat2'] = $this->readHeaderBSI(5); $mixdefbitsread += 5; $thisfile_ac3_raw_bsi['spchan2att'] = $this->readHeaderBSI(3); $mixdefbitsread += 3; } } } $mixdata_bits = (8 * ($thisfile_ac3_raw_bsi['mixdeflen'] + 2)) - $mixdefbitsread; $mixdata_fill = (($mixdata_bits % 8) ? 8 - ($mixdata_bits % 8) : 0); $thisfile_ac3_raw_bsi['mixdata'] = $this->readHeaderBSI($mixdata_bits); $thisfile_ac3_raw_bsi['mixdatafill'] = $this->readHeaderBSI($mixdata_fill); unset($mixdefbitsread, $mixdata_bits, $mixdata_fill); } if ($thisfile_ac3_raw_bsi['acmod'] < 2) { // if mono or dual mono source $thisfile_ac3_raw_bsi['flags']['paninfo'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['paninfo']) { $thisfile_ac3_raw_bsi['panmean'] = $this->readHeaderBSI(8); $thisfile_ac3_raw_bsi['paninfo'] = $this->readHeaderBSI(6); } if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value) $thisfile_ac3_raw_bsi['flags']['paninfo2'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['paninfo2']) { $thisfile_ac3_raw_bsi['panmean2'] = $this->readHeaderBSI(8); $thisfile_ac3_raw_bsi['paninfo2'] = $this->readHeaderBSI(6); } } } $thisfile_ac3_raw_bsi['flags']['frmmixcfginfo'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['frmmixcfginfo']) { // mixing configuration information if ($thisfile_ac3_raw_bsi['numblkscod'] == 0) { $thisfile_ac3_raw_bsi['blkmixcfginfo'][0] = $this->readHeaderBSI(5); } else { for ($blk = 0; $blk < $thisfile_ac3_raw_bsi['numblkscod']; $blk++) { $thisfile_ac3_raw_bsi['flags']['blkmixcfginfo'.$blk] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['blkmixcfginfo'.$blk]) { // mixing configuration information $thisfile_ac3_raw_bsi['blkmixcfginfo'][$blk] = $this->readHeaderBSI(5); } } } } } } $thisfile_ac3_raw_bsi['flags']['infomdat'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['infomdat']) { // Informational metadata $thisfile_ac3_raw_bsi['bsmod'] = $this->readHeaderBSI(3); $thisfile_ac3_raw_bsi['flags']['copyrightb'] = (bool) $this->readHeaderBSI(1); $thisfile_ac3_raw_bsi['flags']['origbs'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['acmod'] == 2) { // if in 2/0 mode $thisfile_ac3_raw_bsi['dsurmod'] = $this->readHeaderBSI(2); $thisfile_ac3_raw_bsi['dheadphonmod'] = $this->readHeaderBSI(2); } if ($thisfile_ac3_raw_bsi['acmod'] >= 6) { // if both surround channels exist $thisfile_ac3_raw_bsi['dsurexmod'] = $this->readHeaderBSI(2); } $thisfile_ac3_raw_bsi['flags']['audprodi'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['audprodi']) { $thisfile_ac3_raw_bsi['mixlevel'] = $this->readHeaderBSI(5); $thisfile_ac3_raw_bsi['roomtyp'] = $this->readHeaderBSI(2); $thisfile_ac3_raw_bsi['flags']['adconvtyp'] = (bool) $this->readHeaderBSI(1); } if ($thisfile_ac3_raw_bsi['acmod'] == 0) { // if 1+1 mode (dual mono, so some items need a second value) $thisfile_ac3_raw_bsi['flags']['audprodi2'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['audprodi2']) { $thisfile_ac3_raw_bsi['mixlevel2'] = $this->readHeaderBSI(5); $thisfile_ac3_raw_bsi['roomtyp2'] = $this->readHeaderBSI(2); $thisfile_ac3_raw_bsi['flags']['adconvtyp2'] = (bool) $this->readHeaderBSI(1); } } if ($thisfile_ac3_raw_bsi['fscod'] < 3) { // if not half sample rate $thisfile_ac3_raw_bsi['flags']['sourcefscod'] = (bool) $this->readHeaderBSI(1); } } if (($thisfile_ac3_raw_bsi['strmtyp'] == 0) && ($thisfile_ac3_raw_bsi['numblkscod'] != 3)) { // if both surround channels exist $thisfile_ac3_raw_bsi['flags']['convsync'] = (bool) $this->readHeaderBSI(1); } if ($thisfile_ac3_raw_bsi['strmtyp'] == 2) { // if bit stream converted from AC-3 if ($thisfile_ac3_raw_bsi['numblkscod'] != 3) { // 6 blocks per syncframe $thisfile_ac3_raw_bsi['flags']['blkid'] = 1; } else { $thisfile_ac3_raw_bsi['flags']['blkid'] = (bool) $this->readHeaderBSI(1); } if ($thisfile_ac3_raw_bsi['flags']['blkid']) { $thisfile_ac3_raw_bsi['frmsizecod'] = $this->readHeaderBSI(6); } } $thisfile_ac3_raw_bsi['flags']['addbsi'] = (bool) $this->readHeaderBSI(1); if ($thisfile_ac3_raw_bsi['flags']['addbsi']) { $thisfile_ac3_raw_bsi['addbsil'] = $this->readHeaderBSI(6); $thisfile_ac3_raw_bsi['addbsi'] = $this->readHeaderBSI(($thisfile_ac3_raw_bsi['addbsil'] + 1) * 8); } } else { $this->error('Bit stream identification is version '.$thisfile_ac3_raw_bsi['bsid'].', but getID3() only understands up to version 16. Please submit a support ticket with a sample file.'); unset($info['ac3']); return false; } if (isset($thisfile_ac3_raw_bsi['fscod2'])) { $thisfile_ac3['sample_rate'] = self::sampleRateCodeLookup2($thisfile_ac3_raw_bsi['fscod2']); } else { $thisfile_ac3['sample_rate'] = self::sampleRateCodeLookup($thisfile_ac3_raw_bsi['fscod']); } if ($thisfile_ac3_raw_bsi['fscod'] <= 3) { $info['audio']['sample_rate'] = $thisfile_ac3['sample_rate']; } else { $this->warning('Unexpected ac3.bsi.fscod value: '.$thisfile_ac3_raw_bsi['fscod']); } if (isset($thisfile_ac3_raw_bsi['frmsizecod'])) { $thisfile_ac3['frame_length'] = self::frameSizeLookup($thisfile_ac3_raw_bsi['frmsizecod'], $thisfile_ac3_raw_bsi['fscod']); $thisfile_ac3['bitrate'] = self::bitrateLookup($thisfile_ac3_raw_bsi['frmsizecod']); } elseif (!empty($thisfile_ac3_raw_bsi['frmsiz'])) { // this isn't right, but it's (usually) close, roughly 5% less than it should be. // but WHERE is the actual bitrate value stored in EAC3?? email info@getid3.org if you know! $thisfile_ac3['bitrate'] = ($thisfile_ac3_raw_bsi['frmsiz'] + 1) * 16 * 30; // The frmsiz field shall contain a value one less than the overall size of the coded syncframe in 16-bit words. That is, this field may assume a value ranging from 0 to 2047, and these values correspond to syncframe sizes ranging from 1 to 2048. // kludge-fix to make it approximately the expected value, still not "right": $thisfile_ac3['bitrate'] = round(($thisfile_ac3['bitrate'] * 1.05) / 16000) * 16000; } $info['audio']['bitrate'] = $thisfile_ac3['bitrate']; if (isset($thisfile_ac3_raw_bsi['bsmod']) && isset($thisfile_ac3_raw_bsi['acmod'])) { $thisfile_ac3['service_type'] = self::serviceTypeLookup($thisfile_ac3_raw_bsi['bsmod'], $thisfile_ac3_raw_bsi['acmod']); } $ac3_coding_mode = self::audioCodingModeLookup($thisfile_ac3_raw_bsi['acmod']); foreach($ac3_coding_mode as $key => $value) { $thisfile_ac3[$key] = $value; } switch ($thisfile_ac3_raw_bsi['acmod']) { case 0: case 1: $info['audio']['channelmode'] = 'mono'; break; case 3: case 4: $info['audio']['channelmode'] = 'stereo'; break; default: $info['audio']['channelmode'] = 'surround'; break; } $info['audio']['channels'] = $thisfile_ac3['num_channels']; $thisfile_ac3['lfe_enabled'] = $thisfile_ac3_raw_bsi['flags']['lfeon']; if ($thisfile_ac3_raw_bsi['flags']['lfeon']) { $info['audio']['channels'] .= '.1'; } $thisfile_ac3['channels_enabled'] = self::channelsEnabledLookup($thisfile_ac3_raw_bsi['acmod'], $thisfile_ac3_raw_bsi['flags']['lfeon']); $thisfile_ac3['dialogue_normalization'] = '-'.$thisfile_ac3_raw_bsi['dialnorm'].'dB'; return true; } /** * @param int $length * * @return int */ private function readHeaderBSI($length) { $data = substr($this->AC3header['bsi'], $this->BSIoffset, $length); $this->BSIoffset += $length; return bindec($data); } /** * @param int $fscod * * @return int|string|false */ public static function sampleRateCodeLookup($fscod) { static $sampleRateCodeLookup = array( 0 => 48000, 1 => 44100, 2 => 32000, 3 => 'reserved' // If the reserved code is indicated, the decoder should not attempt to decode audio and should mute. ); return (isset($sampleRateCodeLookup[$fscod]) ? $sampleRateCodeLookup[$fscod] : false); } /** * @param int $fscod2 * * @return int|string|false */ public static function sampleRateCodeLookup2($fscod2) { static $sampleRateCodeLookup2 = array( 0 => 24000, 1 => 22050, 2 => 16000, 3 => 'reserved' // If the reserved code is indicated, the decoder should not attempt to decode audio and should mute. ); return (isset($sampleRateCodeLookup2[$fscod2]) ? $sampleRateCodeLookup2[$fscod2] : false); } /** * @param int $bsmod * @param int $acmod * * @return string|false */ public static function serviceTypeLookup($bsmod, $acmod) { static $serviceTypeLookup = array(); if (empty($serviceTypeLookup)) { for ($i = 0; $i <= 7; $i++) { $serviceTypeLookup[0][$i] = 'main audio service: complete main (CM)'; $serviceTypeLookup[1][$i] = 'main audio service: music and effects (ME)'; $serviceTypeLookup[2][$i] = 'associated service: visually impaired (VI)'; $serviceTypeLookup[3][$i] = 'associated service: hearing impaired (HI)'; $serviceTypeLookup[4][$i] = 'associated service: dialogue (D)'; $serviceTypeLookup[5][$i] = 'associated service: commentary (C)'; $serviceTypeLookup[6][$i] = 'associated service: emergency (E)'; } $serviceTypeLookup[7][1] = 'associated service: voice over (VO)'; for ($i = 2; $i <= 7; $i++) { $serviceTypeLookup[7][$i] = 'main audio service: karaoke'; } } return (isset($serviceTypeLookup[$bsmod][$acmod]) ? $serviceTypeLookup[$bsmod][$acmod] : false); } /** * @param int $acmod * * @return array|false */ public static function audioCodingModeLookup($acmod) { // array(channel configuration, # channels (not incl LFE), channel order) static $audioCodingModeLookup = array ( 0 => array('channel_config'=>'1+1', 'num_channels'=>2, 'channel_order'=>'Ch1,Ch2'), 1 => array('channel_config'=>'1/0', 'num_channels'=>1, 'channel_order'=>'C'), 2 => array('channel_config'=>'2/0', 'num_channels'=>2, 'channel_order'=>'L,R'), 3 => array('channel_config'=>'3/0', 'num_channels'=>3, 'channel_order'=>'L,C,R'), 4 => array('channel_config'=>'2/1', 'num_channels'=>3, 'channel_order'=>'L,R,S'), 5 => array('channel_config'=>'3/1', 'num_channels'=>4, 'channel_order'=>'L,C,R,S'), 6 => array('channel_config'=>'2/2', 'num_channels'=>4, 'channel_order'=>'L,R,SL,SR'), 7 => array('channel_config'=>'3/2', 'num_channels'=>5, 'channel_order'=>'L,C,R,SL,SR'), ); return (isset($audioCodingModeLookup[$acmod]) ? $audioCodingModeLookup[$acmod] : false); } /** * @param int $cmixlev * * @return int|float|string|false */ public static function centerMixLevelLookup($cmixlev) { static $centerMixLevelLookup; if (empty($centerMixLevelLookup)) { $centerMixLevelLookup = array( 0 => pow(2, -3.0 / 6), // 0.707 (-3.0 dB) 1 => pow(2, -4.5 / 6), // 0.595 (-4.5 dB) 2 => pow(2, -6.0 / 6), // 0.500 (-6.0 dB) 3 => 'reserved' ); } return (isset($centerMixLevelLookup[$cmixlev]) ? $centerMixLevelLookup[$cmixlev] : false); } /** * @param int $surmixlev * * @return int|float|string|false */ public static function surroundMixLevelLookup($surmixlev) { static $surroundMixLevelLookup; if (empty($surroundMixLevelLookup)) { $surroundMixLevelLookup = array( 0 => pow(2, -3.0 / 6), 1 => pow(2, -6.0 / 6), 2 => 0, 3 => 'reserved' ); } return (isset($surroundMixLevelLookup[$surmixlev]) ? $surroundMixLevelLookup[$surmixlev] : false); } /** * @param int $dsurmod * * @return string|false */ public static function dolbySurroundModeLookup($dsurmod) { static $dolbySurroundModeLookup = array( 0 => 'not indicated', 1 => 'Not Dolby Surround encoded', 2 => 'Dolby Surround encoded', 3 => 'reserved' ); return (isset($dolbySurroundModeLookup[$dsurmod]) ? $dolbySurroundModeLookup[$dsurmod] : false); } /** * @param int $acmod * @param bool $lfeon * * @return array */ public static function channelsEnabledLookup($acmod, $lfeon) { $lookup = array( 'ch1'=>($acmod == 0), 'ch2'=>($acmod == 0), 'left'=>($acmod > 1), 'right'=>($acmod > 1), 'center'=>(bool) ($acmod & 0x01), 'surround_mono'=>false, 'surround_left'=>false, 'surround_right'=>false, 'lfe'=>$lfeon); switch ($acmod) { case 4: case 5: $lookup['surround_mono'] = true; break; case 6: case 7: $lookup['surround_left'] = true; $lookup['surround_right'] = true; break; } return $lookup; } /** * @param int $compre * * @return float|int */ public static function heavyCompression($compre) { // The first four bits indicate gain changes in 6.02dB increments which can be // implemented with an arithmetic shift operation. The following four bits // indicate linear gain changes, and require a 5-bit multiply. // We will represent the two 4-bit fields of compr as follows: // X0 X1 X2 X3 . Y4 Y5 Y6 Y7 // The meaning of the X values is most simply described by considering X to represent a 4-bit // signed integer with values from -8 to +7. The gain indicated by X is then (X + 1) * 6.02 dB. The // following table shows this in detail. // Meaning of 4 msb of compr // 7 +48.16 dB // 6 +42.14 dB // 5 +36.12 dB // 4 +30.10 dB // 3 +24.08 dB // 2 +18.06 dB // 1 +12.04 dB // 0 +6.02 dB // -1 0 dB // -2 -6.02 dB // -3 -12.04 dB // -4 -18.06 dB // -5 -24.08 dB // -6 -30.10 dB // -7 -36.12 dB // -8 -42.14 dB $fourbit = str_pad(decbin(($compre & 0xF0) >> 4), 4, '0', STR_PAD_LEFT); if ($fourbit[0] == '1') { $log_gain = -8 + bindec(substr($fourbit, 1)); } else { $log_gain = bindec(substr($fourbit, 1)); } $log_gain = ($log_gain + 1) * getid3_lib::RGADamplitude2dB(2); // The value of Y is a linear representation of a gain change of up to -6 dB. Y is considered to // be an unsigned fractional integer, with a leading value of 1, or: 0.1 Y4 Y5 Y6 Y7 (base 2). Y can // represent values between 0.111112 (or 31/32) and 0.100002 (or 1/2). Thus, Y can represent gain // changes from -0.28 dB to -6.02 dB. $lin_gain = (16 + ($compre & 0x0F)) / 32; // The combination of X and Y values allows compr to indicate gain changes from // 48.16 - 0.28 = +47.89 dB, to // -42.14 - 6.02 = -48.16 dB. return $log_gain - $lin_gain; } /** * @param int $roomtyp * * @return string|false */ public static function roomTypeLookup($roomtyp) { static $roomTypeLookup = array( 0 => 'not indicated', 1 => 'large room, X curve monitor', 2 => 'small room, flat monitor', 3 => 'reserved' ); return (isset($roomTypeLookup[$roomtyp]) ? $roomTypeLookup[$roomtyp] : false); } /** * @param int $frmsizecod * @param int $fscod * * @return int|false */ public static function frameSizeLookup($frmsizecod, $fscod) { // LSB is whether padding is used or not $padding = (bool) ($frmsizecod & 0x01); $framesizeid = ($frmsizecod & 0x3E) >> 1; static $frameSizeLookup = array(); if (empty($frameSizeLookup)) { $frameSizeLookup = array ( 0 => array( 128, 138, 192), // 32 kbps 1 => array( 160, 174, 240), // 40 kbps 2 => array( 192, 208, 288), // 48 kbps 3 => array( 224, 242, 336), // 56 kbps 4 => array( 256, 278, 384), // 64 kbps 5 => array( 320, 348, 480), // 80 kbps 6 => array( 384, 416, 576), // 96 kbps 7 => array( 448, 486, 672), // 112 kbps 8 => array( 512, 556, 768), // 128 kbps 9 => array( 640, 696, 960), // 160 kbps 10 => array( 768, 834, 1152), // 192 kbps 11 => array( 896, 974, 1344), // 224 kbps 12 => array(1024, 1114, 1536), // 256 kbps 13 => array(1280, 1392, 1920), // 320 kbps 14 => array(1536, 1670, 2304), // 384 kbps 15 => array(1792, 1950, 2688), // 448 kbps 16 => array(2048, 2228, 3072), // 512 kbps 17 => array(2304, 2506, 3456), // 576 kbps 18 => array(2560, 2786, 3840) // 640 kbps ); } $paddingBytes = 0; if (($fscod == 1) && $padding) { // frame lengths are padded by 1 word (16 bits) at 44100 // (fscode==1) means 44100Hz (see sampleRateCodeLookup) $paddingBytes = 2; } return (isset($frameSizeLookup[$framesizeid][$fscod]) ? $frameSizeLookup[$framesizeid][$fscod] + $paddingBytes : false); } /** * @param int $frmsizecod * * @return int|false */ public static function bitrateLookup($frmsizecod) { // LSB is whether padding is used or not $padding = (bool) ($frmsizecod & 0x01); $framesizeid = ($frmsizecod & 0x3E) >> 1; static $bitrateLookup = array( 0 => 32000, 1 => 40000, 2 => 48000, 3 => 56000, 4 => 64000, 5 => 80000, 6 => 96000, 7 => 112000, 8 => 128000, 9 => 160000, 10 => 192000, 11 => 224000, 12 => 256000, 13 => 320000, 14 => 384000, 15 => 448000, 16 => 512000, 17 => 576000, 18 => 640000, ); return (isset($bitrateLookup[$framesizeid]) ? $bitrateLookup[$framesizeid] : false); } /** * @param int $numblkscod * * @return int|false */ public static function blocksPerSyncFrame($numblkscod) { static $blocksPerSyncFrameLookup = array( 0 => 1, 1 => 2, 2 => 3, 3 => 6, ); return (isset($blocksPerSyncFrameLookup[$numblkscod]) ? $blocksPerSyncFrameLookup[$numblkscod] : false); } }