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<?php |
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///////////////////////////////////////////////////////////////// |
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/// getID3() by James Heinrich <[email protected]> // |
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// available at http://getid3.sourceforge.net // |
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// or http://www.getid3.org // |
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// also https://github.com/JamesHeinrich/getID3 // |
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///////////////////////////////////////////////////////////////// |
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// See readme.txt for more details // |
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///////////////////////////////////////////////////////////////// |
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// // |
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// module.audio.ac3.php // |
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// module for analyzing AC-3 (aka Dolby Digital) audio files // |
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// dependencies: NONE // |
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// /// |
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///////////////////////////////////////////////////////////////// |
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class getid3_ac3 extends getid3_handler |
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{ |
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private $AC3header = array(); |
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private $BSIoffset = 0; |
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const syncword = "\x0B\x77"; |
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public function Analyze() { |
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$info = &$this->getid3->info; |
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///AH |
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$info['ac3']['raw']['bsi'] = array(); |
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$thisfile_ac3 = &$info['ac3']; |
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$thisfile_ac3_raw = &$thisfile_ac3['raw']; |
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$thisfile_ac3_raw_bsi = &$thisfile_ac3_raw['bsi']; |
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// http://www.atsc.org/standards/a_52a.pdf |
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$info['fileformat'] = 'ac3'; |
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// An AC-3 serial coded audio bit stream is made up of a sequence of synchronization frames |
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// Each synchronization frame contains 6 coded audio blocks (AB), each of which represent 256 |
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// new audio samples per channel. A synchronization information (SI) header at the beginning |
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// of each frame contains information needed to acquire and maintain synchronization. A |
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// bit stream information (BSI) header follows SI, and contains parameters describing the coded |
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// audio service. The coded audio blocks may be followed by an auxiliary data (Aux) field. At the |
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// end of each frame is an error check field that includes a CRC word for error detection. An |
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// additional CRC word is located in the SI header, the use of which, by a decoder, is optional. |
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// |
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// syncinfo() | bsi() | AB0 | AB1 | AB2 | AB3 | AB4 | AB5 | Aux | CRC |
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// syncinfo() { |
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// syncword 16 |
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// crc1 16 |
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// fscod 2 |
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// frmsizecod 6 |
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// } /* end of syncinfo */ |
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$this->fseek($info['avdataoffset']); |
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$this->AC3header['syncinfo'] = $this->fread(5); |
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if (strpos($this->AC3header['syncinfo'], self::syncword) === 0) { |
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$thisfile_ac3_raw['synchinfo']['synchword'] = self::syncword; |
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$offset = 2; |
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} else { |
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if (!$this->isDependencyFor('matroska')) { |
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unset($info['fileformat'], $info['ac3']); |
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return $this->error('Expecting "'.getid3_lib::PrintHexBytes(self::syncword).'" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes(substr($this->AC3header['syncinfo'], 0, 2)).'"'); |
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} |
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$offset = 0; |
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$this->fseek(-2, SEEK_CUR); |
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} |
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$info['audio']['dataformat'] = 'ac3'; |
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$info['audio']['bitrate_mode'] = 'cbr'; |
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$info['audio']['lossless'] = false; |
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$thisfile_ac3_raw['synchinfo']['crc1'] = getid3_lib::LittleEndian2Int(substr($this->AC3header['syncinfo'], $offset, 2)); |
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$ac3_synchinfo_fscod_frmsizecod = getid3_lib::LittleEndian2Int(substr($this->AC3header['syncinfo'], ($offset + 2), 1)); |
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$thisfile_ac3_raw['synchinfo']['fscod'] = ($ac3_synchinfo_fscod_frmsizecod & 0xC0) >> 6; |
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$thisfile_ac3_raw['synchinfo']['frmsizecod'] = ($ac3_synchinfo_fscod_frmsizecod & 0x3F); |
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$thisfile_ac3['sample_rate'] = self::sampleRateCodeLookup($thisfile_ac3_raw['synchinfo']['fscod']); |
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if ($thisfile_ac3_raw['synchinfo']['fscod'] <= 3) { |
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$info['audio']['sample_rate'] = $thisfile_ac3['sample_rate']; |
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} |
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$thisfile_ac3['frame_length'] = self::frameSizeLookup($thisfile_ac3_raw['synchinfo']['frmsizecod'], $thisfile_ac3_raw['synchinfo']['fscod']); |
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$thisfile_ac3['bitrate'] = self::bitrateLookup($thisfile_ac3_raw['synchinfo']['frmsizecod']); |
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$info['audio']['bitrate'] = $thisfile_ac3['bitrate']; |
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$this->AC3header['bsi'] = getid3_lib::BigEndian2Bin($this->fread(15)); |
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$ac3_bsi_offset = 0; |
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$thisfile_ac3_raw_bsi['bsid'] = $this->readHeaderBSI(5); |
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if ($thisfile_ac3_raw_bsi['bsid'] > 8) { |
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// Decoders which can decode version 8 will thus be able to decode version numbers less than 8. |
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// If this standard is extended by the addition of additional elements or features, a value of bsid greater than 8 will be used. |
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// Decoders built to this version of the standard will not be able to decode versions with bsid greater than 8. |
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$this->error('Bit stream identification is version '.$thisfile_ac3_raw_bsi['bsid'].', but getID3() only understands up to version 8'); |
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unset($info['ac3']); |
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return false; |
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} |
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$thisfile_ac3_raw_bsi['bsmod'] = $this->readHeaderBSI(3); |
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$thisfile_ac3_raw_bsi['acmod'] = $this->readHeaderBSI(3); |
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$thisfile_ac3['service_type'] = self::serviceTypeLookup($thisfile_ac3_raw_bsi['bsmod'], $thisfile_ac3_raw_bsi['acmod']); |
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$ac3_coding_mode = self::audioCodingModeLookup($thisfile_ac3_raw_bsi['acmod']); |
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foreach($ac3_coding_mode as $key => $value) { |
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$thisfile_ac3[$key] = $value; |
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} |
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switch ($thisfile_ac3_raw_bsi['acmod']) { |
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case 0: |
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case 1: |
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$info['audio']['channelmode'] = 'mono'; |
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break; |
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case 3: |
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case 4: |
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$info['audio']['channelmode'] = 'stereo'; |
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break; |
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default: |
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$info['audio']['channelmode'] = 'surround'; |
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break; |
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} |
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$info['audio']['channels'] = $thisfile_ac3['num_channels']; |
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if ($thisfile_ac3_raw_bsi['acmod'] & 0x01) { |
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// If the lsb of acmod is a 1, center channel is in use and cmixlev follows in the bit stream. |
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$thisfile_ac3_raw_bsi['cmixlev'] = $this->readHeaderBSI(2); |
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$thisfile_ac3['center_mix_level'] = self::centerMixLevelLookup($thisfile_ac3_raw_bsi['cmixlev']); |
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} |
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if ($thisfile_ac3_raw_bsi['acmod'] & 0x04) { |
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// If the msb of acmod is a 1, surround channels are in use and surmixlev follows in the bit stream. |
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$thisfile_ac3_raw_bsi['surmixlev'] = $this->readHeaderBSI(2); |
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$thisfile_ac3['surround_mix_level'] = self::surroundMixLevelLookup($thisfile_ac3_raw_bsi['surmixlev']); |
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} |
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if ($thisfile_ac3_raw_bsi['acmod'] == 0x02) { |
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// When operating in the two channel mode, this 2-bit code indicates whether or not the program has been encoded in Dolby Surround. |
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$thisfile_ac3_raw_bsi['dsurmod'] = $this->readHeaderBSI(2); |
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$thisfile_ac3['dolby_surround_mode'] = self::dolbySurroundModeLookup($thisfile_ac3_raw_bsi['dsurmod']); |
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} |
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$thisfile_ac3_raw_bsi['lfeon'] = (bool) $this->readHeaderBSI(1); |
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$thisfile_ac3['lfe_enabled'] = $thisfile_ac3_raw_bsi['lfeon']; |
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if ($thisfile_ac3_raw_bsi['lfeon']) { |
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//$info['audio']['channels']++; |
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$info['audio']['channels'] .= '.1'; |
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} |
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$thisfile_ac3['channels_enabled'] = self::channelsEnabledLookup($thisfile_ac3_raw_bsi['acmod'], $thisfile_ac3_raw_bsi['lfeon']); |
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// This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1-31. |
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// The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent. |
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$thisfile_ac3_raw_bsi['dialnorm'] = $this->readHeaderBSI(5); |
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$thisfile_ac3['dialogue_normalization'] = '-'.$thisfile_ac3_raw_bsi['dialnorm'].'dB'; |
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$thisfile_ac3_raw_bsi['compre_flag'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['compre_flag']) { |
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$thisfile_ac3_raw_bsi['compr'] = $this->readHeaderBSI(8); |
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$thisfile_ac3['heavy_compression'] = self::heavyCompression($thisfile_ac3_raw_bsi['compr']); |
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} |
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$thisfile_ac3_raw_bsi['langcode_flag'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['langcode_flag']) { |
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$thisfile_ac3_raw_bsi['langcod'] = $this->readHeaderBSI(8); |
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} |
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$thisfile_ac3_raw_bsi['audprodie'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['audprodie']) { |
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$thisfile_ac3_raw_bsi['mixlevel'] = $this->readHeaderBSI(5); |
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$thisfile_ac3_raw_bsi['roomtyp'] = $this->readHeaderBSI(2); |
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$thisfile_ac3['mixing_level'] = (80 + $thisfile_ac3_raw_bsi['mixlevel']).'dB'; |
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$thisfile_ac3['room_type'] = self::roomTypeLookup($thisfile_ac3_raw_bsi['roomtyp']); |
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} |
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if ($thisfile_ac3_raw_bsi['acmod'] == 0x00) { |
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// If acmod is 0, then two completely independent program channels (dual mono) |
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// are encoded into the bit stream, and are referenced as Ch1, Ch2. In this case, |
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// a number of additional items are present in BSI or audblk to fully describe Ch2. |
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// This indicates how far the average dialogue level is below digital 100 percent. Valid values are 1-31. |
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// 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. |
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$thisfile_ac3_raw_bsi['dialnorm2'] = $this->readHeaderBSI(5); |
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$thisfile_ac3['dialogue_normalization2'] = '-'.$thisfile_ac3_raw_bsi['dialnorm2'].'dB'; |
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$thisfile_ac3_raw_bsi['compre_flag2'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['compre_flag2']) { |
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$thisfile_ac3_raw_bsi['compr2'] = $this->readHeaderBSI(8); |
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$thisfile_ac3['heavy_compression2'] = self::heavyCompression($thisfile_ac3_raw_bsi['compr2']); |
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} |
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$thisfile_ac3_raw_bsi['langcode_flag2'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['langcode_flag2']) { |
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$thisfile_ac3_raw_bsi['langcod2'] = $this->readHeaderBSI(8); |
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} |
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$thisfile_ac3_raw_bsi['audprodie2'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['audprodie2']) { |
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$thisfile_ac3_raw_bsi['mixlevel2'] = $this->readHeaderBSI(5); |
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$thisfile_ac3_raw_bsi['roomtyp2'] = $this->readHeaderBSI(2); |
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$thisfile_ac3['mixing_level2'] = (80 + $thisfile_ac3_raw_bsi['mixlevel2']).'dB'; |
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$thisfile_ac3['room_type2'] = self::roomTypeLookup($thisfile_ac3_raw_bsi['roomtyp2']); |
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} |
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208
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} |
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$thisfile_ac3_raw_bsi['copyright'] = (bool) $this->readHeaderBSI(1); |
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212
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$thisfile_ac3_raw_bsi['original'] = (bool) $this->readHeaderBSI(1); |
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214
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$thisfile_ac3_raw_bsi['timecode1_flag'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['timecode1_flag']) { |
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$thisfile_ac3_raw_bsi['timecode1'] = $this->readHeaderBSI(14); |
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} |
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$thisfile_ac3_raw_bsi['timecode2_flag'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['timecode2_flag']) { |
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$thisfile_ac3_raw_bsi['timecode2'] = $this->readHeaderBSI(14); |
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} |
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223
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224
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$thisfile_ac3_raw_bsi['addbsi_flag'] = (bool) $this->readHeaderBSI(1); |
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if ($thisfile_ac3_raw_bsi['addbsi_flag']) { |
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$thisfile_ac3_raw_bsi['addbsi_length'] = $this->readHeaderBSI(6); |
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228
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$this->AC3header['bsi'] .= getid3_lib::BigEndian2Bin($this->fread($thisfile_ac3_raw_bsi['addbsi_length'])); |
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230
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$thisfile_ac3_raw_bsi['addbsi_data'] = substr($this->AC3header['bsi'], $this->BSIoffset, $thisfile_ac3_raw_bsi['addbsi_length'] * 8); |
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$this->BSIoffset += $thisfile_ac3_raw_bsi['addbsi_length'] * 8; |
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} |
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return true; |
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} |
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237
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private function readHeaderBSI($length) { |
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$data = substr($this->AC3header['bsi'], $this->BSIoffset, $length); |
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$this->BSIoffset += $length; |
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return bindec($data); |
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} |
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public static function sampleRateCodeLookup($fscod) { |
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245
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static $sampleRateCodeLookup = array( |
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0 => 48000, |
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247
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1 => 44100, |
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2 => 32000, |
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3 => 'reserved' // If the reserved code is indicated, the decoder should not attempt to decode audio and should mute. |
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250
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); |
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return (isset($sampleRateCodeLookup[$fscod]) ? $sampleRateCodeLookup[$fscod] : false); |
|
252
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} |
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253
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|
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254
|
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public static function serviceTypeLookup($bsmod, $acmod) { |
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255
|
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static $serviceTypeLookup = array(); |
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256
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if (empty($serviceTypeLookup)) { |
|
257
|
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for ($i = 0; $i <= 7; $i++) { |
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258
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$serviceTypeLookup[0][$i] = 'main audio service: complete main (CM)'; |
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259
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$serviceTypeLookup[1][$i] = 'main audio service: music and effects (ME)'; |
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260
|
|
|
$serviceTypeLookup[2][$i] = 'associated service: visually impaired (VI)'; |
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261
|
|
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$serviceTypeLookup[3][$i] = 'associated service: hearing impaired (HI)'; |
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262
|
|
|
$serviceTypeLookup[4][$i] = 'associated service: dialogue (D)'; |
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263
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|
$serviceTypeLookup[5][$i] = 'associated service: commentary (C)'; |
|
264
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|
$serviceTypeLookup[6][$i] = 'associated service: emergency (E)'; |
|
265
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} |
|
266
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|
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267
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$serviceTypeLookup[7][1] = 'associated service: voice over (VO)'; |
|
268
|
|
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for ($i = 2; $i <= 7; $i++) { |
|
269
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|
$serviceTypeLookup[7][$i] = 'main audio service: karaoke'; |
|
270
|
|
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} |
|
271
|
|
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} |
|
272
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|
|
return (isset($serviceTypeLookup[$bsmod][$acmod]) ? $serviceTypeLookup[$bsmod][$acmod] : false); |
|
273
|
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} |
|
274
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275
|
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|
public static function audioCodingModeLookup($acmod) { |
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|
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276
|
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// array(channel configuration, # channels (not incl LFE), channel order) |
|
277
|
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static $audioCodingModeLookup = array ( |
|
278
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0 => array('channel_config'=>'1+1', 'num_channels'=>2, 'channel_order'=>'Ch1,Ch2'), |
|
279
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1 => array('channel_config'=>'1/0', 'num_channels'=>1, 'channel_order'=>'C'), |
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280
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2 => array('channel_config'=>'2/0', 'num_channels'=>2, 'channel_order'=>'L,R'), |
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281
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3 => array('channel_config'=>'3/0', 'num_channels'=>3, 'channel_order'=>'L,C,R'), |
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282
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4 => array('channel_config'=>'2/1', 'num_channels'=>3, 'channel_order'=>'L,R,S'), |
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283
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5 => array('channel_config'=>'3/1', 'num_channels'=>4, 'channel_order'=>'L,C,R,S'), |
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284
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6 => array('channel_config'=>'2/2', 'num_channels'=>4, 'channel_order'=>'L,R,SL,SR'), |
|
285
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|
7 => array('channel_config'=>'3/2', 'num_channels'=>5, 'channel_order'=>'L,C,R,SL,SR'), |
|
286
|
|
|
); |
|
287
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|
|
return (isset($audioCodingModeLookup[$acmod]) ? $audioCodingModeLookup[$acmod] : false); |
|
288
|
|
|
} |
|
289
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|
290
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|
View Code Duplication |
public static function centerMixLevelLookup($cmixlev) { |
|
291
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|
|
static $centerMixLevelLookup; |
|
292
|
|
|
if (empty($centerMixLevelLookup)) { |
|
293
|
|
|
$centerMixLevelLookup = array( |
|
294
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|
|
0 => pow(2, -3.0 / 6), // 0.707 (-3.0 dB) |
|
295
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|
|
1 => pow(2, -4.5 / 6), // 0.595 (-4.5 dB) |
|
296
|
|
|
2 => pow(2, -6.0 / 6), // 0.500 (-6.0 dB) |
|
297
|
|
|
3 => 'reserved' |
|
298
|
|
|
); |
|
299
|
|
|
} |
|
300
|
|
|
return (isset($centerMixLevelLookup[$cmixlev]) ? $centerMixLevelLookup[$cmixlev] : false); |
|
301
|
|
|
} |
|
302
|
|
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|
|
303
|
|
View Code Duplication |
public static function surroundMixLevelLookup($surmixlev) { |
|
304
|
|
|
static $surroundMixLevelLookup; |
|
305
|
|
|
if (empty($surroundMixLevelLookup)) { |
|
306
|
|
|
$surroundMixLevelLookup = array( |
|
307
|
|
|
0 => pow(2, -3.0 / 6), |
|
308
|
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|
1 => pow(2, -6.0 / 6), |
|
309
|
|
|
2 => 0, |
|
310
|
|
|
3 => 'reserved' |
|
311
|
|
|
); |
|
312
|
|
|
} |
|
313
|
|
|
return (isset($surroundMixLevelLookup[$surmixlev]) ? $surroundMixLevelLookup[$surmixlev] : false); |
|
314
|
|
|
} |
|
315
|
|
|
|
|
316
|
|
|
public static function dolbySurroundModeLookup($dsurmod) { |
|
|
|
|
|
|
317
|
|
|
static $dolbySurroundModeLookup = array( |
|
318
|
|
|
0 => 'not indicated', |
|
319
|
|
|
1 => 'Not Dolby Surround encoded', |
|
320
|
|
|
2 => 'Dolby Surround encoded', |
|
321
|
|
|
3 => 'reserved' |
|
322
|
|
|
); |
|
323
|
|
|
return (isset($dolbySurroundModeLookup[$dsurmod]) ? $dolbySurroundModeLookup[$dsurmod] : false); |
|
324
|
|
|
} |
|
325
|
|
|
|
|
326
|
|
|
public static function channelsEnabledLookup($acmod, $lfeon) { |
|
327
|
|
|
$lookup = array( |
|
328
|
|
|
'ch1'=>(bool) ($acmod == 0), |
|
329
|
|
|
'ch2'=>(bool) ($acmod == 0), |
|
330
|
|
|
'left'=>(bool) ($acmod > 1), |
|
331
|
|
|
'right'=>(bool) ($acmod > 1), |
|
332
|
|
|
'center'=>(bool) ($acmod & 0x01), |
|
333
|
|
|
'surround_mono'=>false, |
|
334
|
|
|
'surround_left'=>false, |
|
335
|
|
|
'surround_right'=>false, |
|
336
|
|
|
'lfe'=>$lfeon); |
|
337
|
|
|
switch ($acmod) { |
|
338
|
|
|
case 4: |
|
339
|
|
|
case 5: |
|
340
|
|
|
$lookup['surround_mono'] = true; |
|
341
|
|
|
break; |
|
342
|
|
|
case 6: |
|
343
|
|
|
case 7: |
|
344
|
|
|
$lookup['surround_left'] = true; |
|
345
|
|
|
$lookup['surround_right'] = true; |
|
346
|
|
|
break; |
|
347
|
|
|
} |
|
348
|
|
|
return $lookup; |
|
349
|
|
|
} |
|
350
|
|
|
|
|
351
|
|
|
public static function heavyCompression($compre) { |
|
352
|
|
|
// The first four bits indicate gain changes in 6.02dB increments which can be |
|
353
|
|
|
// implemented with an arithmetic shift operation. The following four bits |
|
354
|
|
|
// indicate linear gain changes, and require a 5-bit multiply. |
|
355
|
|
|
// We will represent the two 4-bit fields of compr as follows: |
|
356
|
|
|
// X0 X1 X2 X3 . Y4 Y5 Y6 Y7 |
|
357
|
|
|
// The meaning of the X values is most simply described by considering X to represent a 4-bit |
|
358
|
|
|
// signed integer with values from -8 to +7. The gain indicated by X is then (X + 1) * 6.02 dB. The |
|
359
|
|
|
// following table shows this in detail. |
|
360
|
|
|
|
|
361
|
|
|
// Meaning of 4 msb of compr |
|
362
|
|
|
// 7 +48.16 dB |
|
363
|
|
|
// 6 +42.14 dB |
|
364
|
|
|
// 5 +36.12 dB |
|
365
|
|
|
// 4 +30.10 dB |
|
366
|
|
|
// 3 +24.08 dB |
|
367
|
|
|
// 2 +18.06 dB |
|
368
|
|
|
// 1 +12.04 dB |
|
369
|
|
|
// 0 +6.02 dB |
|
370
|
|
|
// -1 0 dB |
|
371
|
|
|
// -2 -6.02 dB |
|
372
|
|
|
// -3 -12.04 dB |
|
373
|
|
|
// -4 -18.06 dB |
|
374
|
|
|
// -5 -24.08 dB |
|
375
|
|
|
// -6 -30.10 dB |
|
376
|
|
|
// -7 -36.12 dB |
|
377
|
|
|
// -8 -42.14 dB |
|
378
|
|
|
|
|
379
|
|
|
$fourbit = str_pad(decbin(($compre & 0xF0) >> 4), 4, '0', STR_PAD_LEFT); |
|
380
|
|
|
if ($fourbit{0} == '1') { |
|
381
|
|
|
$log_gain = -8 + bindec(substr($fourbit, 1)); |
|
382
|
|
|
} else { |
|
383
|
|
|
$log_gain = bindec(substr($fourbit, 1)); |
|
384
|
|
|
} |
|
385
|
|
|
$log_gain = ($log_gain + 1) * getid3_lib::RGADamplitude2dB(2); |
|
386
|
|
|
|
|
387
|
|
|
// The value of Y is a linear representation of a gain change of up to -6 dB. Y is considered to |
|
388
|
|
|
// be an unsigned fractional integer, with a leading value of 1, or: 0.1 Y4 Y5 Y6 Y7 (base 2). Y can |
|
389
|
|
|
// represent values between 0.111112 (or 31/32) and 0.100002 (or 1/2). Thus, Y can represent gain |
|
390
|
|
|
// changes from -0.28 dB to -6.02 dB. |
|
391
|
|
|
|
|
392
|
|
|
$lin_gain = (16 + ($compre & 0x0F)) / 32; |
|
393
|
|
|
|
|
394
|
|
|
// The combination of X and Y values allows compr to indicate gain changes from |
|
395
|
|
|
// 48.16 - 0.28 = +47.89 dB, to |
|
396
|
|
|
// -42.14 - 6.02 = -48.16 dB. |
|
397
|
|
|
|
|
398
|
|
|
return $log_gain - $lin_gain; |
|
399
|
|
|
} |
|
400
|
|
|
|
|
401
|
|
|
public static function roomTypeLookup($roomtyp) { |
|
|
|
|
|
|
402
|
|
|
static $roomTypeLookup = array( |
|
403
|
|
|
0 => 'not indicated', |
|
404
|
|
|
1 => 'large room, X curve monitor', |
|
405
|
|
|
2 => 'small room, flat monitor', |
|
406
|
|
|
3 => 'reserved' |
|
407
|
|
|
); |
|
408
|
|
|
return (isset($roomTypeLookup[$roomtyp]) ? $roomTypeLookup[$roomtyp] : false); |
|
409
|
|
|
} |
|
410
|
|
|
|
|
411
|
|
|
public static function frameSizeLookup($frmsizecod, $fscod) { |
|
|
|
|
|
|
412
|
|
|
$padding = (bool) ($frmsizecod % 2); |
|
413
|
|
|
$framesizeid = floor($frmsizecod / 2); |
|
414
|
|
|
|
|
415
|
|
|
static $frameSizeLookup = array(); |
|
416
|
|
|
if (empty($frameSizeLookup)) { |
|
417
|
|
|
$frameSizeLookup = array ( |
|
418
|
|
|
0 => array(128, 138, 192), |
|
419
|
|
|
1 => array(40, 160, 174, 240), |
|
420
|
|
|
2 => array(48, 192, 208, 288), |
|
421
|
|
|
3 => array(56, 224, 242, 336), |
|
422
|
|
|
4 => array(64, 256, 278, 384), |
|
423
|
|
|
5 => array(80, 320, 348, 480), |
|
424
|
|
|
6 => array(96, 384, 416, 576), |
|
425
|
|
|
7 => array(112, 448, 486, 672), |
|
426
|
|
|
8 => array(128, 512, 556, 768), |
|
427
|
|
|
9 => array(160, 640, 696, 960), |
|
428
|
|
|
10 => array(192, 768, 834, 1152), |
|
429
|
|
|
11 => array(224, 896, 974, 1344), |
|
430
|
|
|
12 => array(256, 1024, 1114, 1536), |
|
431
|
|
|
13 => array(320, 1280, 1392, 1920), |
|
432
|
|
|
14 => array(384, 1536, 1670, 2304), |
|
433
|
|
|
15 => array(448, 1792, 1950, 2688), |
|
434
|
|
|
16 => array(512, 2048, 2228, 3072), |
|
435
|
|
|
17 => array(576, 2304, 2506, 3456), |
|
436
|
|
|
18 => array(640, 2560, 2786, 3840) |
|
437
|
|
|
); |
|
438
|
|
|
} |
|
439
|
|
|
if (($fscod == 1) && $padding) { |
|
440
|
|
|
// frame lengths are padded by 1 word (16 bits) at 44100 |
|
441
|
|
|
$frameSizeLookup[$frmsizecod] += 2; |
|
442
|
|
|
} |
|
443
|
|
|
return (isset($frameSizeLookup[$framesizeid][$fscod]) ? $frameSizeLookup[$framesizeid][$fscod] : false); |
|
444
|
|
|
} |
|
445
|
|
|
|
|
446
|
|
|
public static function bitrateLookup($frmsizecod) { |
|
|
|
|
|
|
447
|
|
|
$framesizeid = floor($frmsizecod / 2); |
|
448
|
|
|
|
|
449
|
|
|
static $bitrateLookup = array( |
|
450
|
|
|
0 => 32000, |
|
451
|
|
|
1 => 40000, |
|
452
|
|
|
2 => 48000, |
|
453
|
|
|
3 => 56000, |
|
454
|
|
|
4 => 64000, |
|
455
|
|
|
5 => 80000, |
|
456
|
|
|
6 => 96000, |
|
457
|
|
|
7 => 112000, |
|
458
|
|
|
8 => 128000, |
|
459
|
|
|
9 => 160000, |
|
460
|
|
|
10 => 192000, |
|
461
|
|
|
11 => 224000, |
|
462
|
|
|
12 => 256000, |
|
463
|
|
|
13 => 320000, |
|
464
|
|
|
14 => 384000, |
|
465
|
|
|
15 => 448000, |
|
466
|
|
|
16 => 512000, |
|
467
|
|
|
17 => 576000, |
|
468
|
|
|
18 => 640000 |
|
469
|
|
|
); |
|
470
|
|
|
return (isset($bitrateLookup[$framesizeid]) ? $bitrateLookup[$framesizeid] : false); |
|
471
|
|
|
} |
|
472
|
|
|
|
|
473
|
|
|
|
|
474
|
|
|
} |
|
475
|
|
|
|
ntwb /
wordpress
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Our type inference engine in quite powerful, but sometimes the code does not provide enough clues to go by. In these cases we request you to add a
@returnannotation as described here.