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<?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.dts.php                                        //
// module for analyzing DTS Audio files                        //
// dependencies: NONE                                          //
//                                                             //
/////////////////////////////////////////////////////////////////

if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers
	exit;
}

/**
* @tutorial http://wiki.multimedia.cx/index.php?title=DTS
*/
class getid3_dts extends getid3_handler
{
	/**
	 * Default DTS syncword used in native .cpt or .dts formats.
	 */
	const syncword = "\x7F\xFE\x80\x01";

	/**
	 * @var int
	 */
	private $readBinDataOffset = 0;

	/**
	 * Possible syncwords indicating bitstream encoding.
	 */
	public static $syncwords = array(
		0 => "\x7F\xFE\x80\x01",  // raw big-endian
		1 => "\xFE\x7F\x01\x80",  // raw little-endian
		2 => "\x1F\xFF\xE8\x00",  // 14-bit big-endian
		3 => "\xFF\x1F\x00\xE8"); // 14-bit little-endian

	/**
	 * @return bool
	 */
	public function Analyze() {
		$info = &$this->getid3->info;
		$info['fileformat'] = 'dts';

		$this->fseek($info['avdataoffset']);
		$DTSheader = $this->fread(20); // we only need 2 words magic + 6 words frame header, but these words may be normal 16-bit words OR 14-bit words with 2 highest bits set to zero, so 8 words can be either 8*16/8 = 16 bytes OR 8*16*(16/14)/8 = 18.3 bytes

		// check syncword
		$sync = substr($DTSheader, 0, 4);
		if (($encoding = array_search($sync, self::$syncwords)) !== false) {

			$info['dts']['raw']['magic'] = $sync;
			$this->readBinDataOffset = 32;

		} elseif ($this->isDependencyFor('matroska')) {

			// Matroska contains DTS without syncword encoded as raw big-endian format
			$encoding = 0;
			$this->readBinDataOffset = 0;

		} else {

			unset($info['fileformat']);
			return $this->error('Expecting "'.implode('| ', array_map('getid3_lib::PrintHexBytes', self::$syncwords)).'" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes($sync).'"');

		}

		// decode header
		$fhBS = '';
		for ($word_offset = 0; $word_offset <= strlen($DTSheader); $word_offset += 2) {
			switch ($encoding) {
				case 0: // raw big-endian
					$fhBS .=        getid3_lib::BigEndian2Bin(       substr($DTSheader, $word_offset, 2) );
					break;
				case 1: // raw little-endian
					$fhBS .=        getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2)));
					break;
				case 2: // 14-bit big-endian
					$fhBS .= substr(getid3_lib::BigEndian2Bin(       substr($DTSheader, $word_offset, 2) ), 2, 14);
					break;
				case 3: // 14-bit little-endian
					$fhBS .= substr(getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2))), 2, 14);
					break;
			}
		}

		$info['dts']['raw']['frame_type']             =        $this->readBinData($fhBS,  1);
		$info['dts']['raw']['deficit_samples']        =        $this->readBinData($fhBS,  5);
		$info['dts']['flags']['crc_present']          = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['raw']['pcm_sample_blocks']      =        $this->readBinData($fhBS,  7);
		$info['dts']['raw']['frame_byte_size']        =        $this->readBinData($fhBS, 14);
		$info['dts']['raw']['channel_arrangement']    =        $this->readBinData($fhBS,  6);
		$info['dts']['raw']['sample_frequency']       =        $this->readBinData($fhBS,  4);
		$info['dts']['raw']['bitrate']                =        $this->readBinData($fhBS,  5);
		$info['dts']['flags']['embedded_downmix']     = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['flags']['dynamicrange']         = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['flags']['timestamp']            = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['flags']['auxdata']              = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['flags']['hdcd']                 = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['raw']['extension_audio']        =        $this->readBinData($fhBS,  3);
		$info['dts']['flags']['extended_coding']      = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['flags']['audio_sync_insertion'] = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['raw']['lfe_effects']            =        $this->readBinData($fhBS,  2);
		$info['dts']['flags']['predictor_history']    = (bool) $this->readBinData($fhBS,  1);
		if ($info['dts']['flags']['crc_present']) {
			$info['dts']['raw']['crc16']              =        $this->readBinData($fhBS, 16);
		}
		$info['dts']['flags']['mri_perfect_reconst']  = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['raw']['encoder_soft_version']   =        $this->readBinData($fhBS,  4);
		$info['dts']['raw']['copy_history']           =        $this->readBinData($fhBS,  2);
		$info['dts']['raw']['bits_per_sample']        =        $this->readBinData($fhBS,  2);
		$info['dts']['flags']['surround_es']          = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['flags']['front_sum_diff']       = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['flags']['surround_sum_diff']    = (bool) $this->readBinData($fhBS,  1);
		$info['dts']['raw']['dialog_normalization']   =        $this->readBinData($fhBS,  4);


		$info['dts']['bitrate']              = self::bitrateLookup($info['dts']['raw']['bitrate']);
		$info['dts']['bits_per_sample']      = self::bitPerSampleLookup($info['dts']['raw']['bits_per_sample']);
		$info['dts']['sample_rate']          = self::sampleRateLookup($info['dts']['raw']['sample_frequency']);
		$info['dts']['dialog_normalization'] = self::dialogNormalization($info['dts']['raw']['dialog_normalization'], $info['dts']['raw']['encoder_soft_version']);
		$info['dts']['flags']['lossless']    = (($info['dts']['raw']['bitrate'] == 31) ? true  : false);
		$info['dts']['bitrate_mode']         = (($info['dts']['raw']['bitrate'] == 30) ? 'vbr' : 'cbr');
		$info['dts']['channels']             = self::numChannelsLookup($info['dts']['raw']['channel_arrangement']);
		$info['dts']['channel_arrangement']  = self::channelArrangementLookup($info['dts']['raw']['channel_arrangement']);

		$info['audio']['dataformat']          = 'dts';
		$info['audio']['lossless']            = $info['dts']['flags']['lossless'];
		$info['audio']['bitrate_mode']        = $info['dts']['bitrate_mode'];
		$info['audio']['bits_per_sample']     = $info['dts']['bits_per_sample'];
		$info['audio']['sample_rate']         = $info['dts']['sample_rate'];
		$info['audio']['channels']            = $info['dts']['channels'];
		$info['audio']['bitrate']             = $info['dts']['bitrate'];
		if (isset($info['avdataend']) && !empty($info['dts']['bitrate']) && is_numeric($info['dts']['bitrate'])) {
			$info['playtime_seconds']         = ($info['avdataend'] - $info['avdataoffset']) / ($info['dts']['bitrate'] / 8);
			if (($encoding == 2) || ($encoding == 3)) {
				// 14-bit data packed into 16-bit words, so the playtime is wrong because only (14/16) of the bytes in the data portion of the file are used at the specified bitrate
				$info['playtime_seconds'] *= (14 / 16);
			}
		}
		return true;
	}

	/**
	 * @param string $bin
	 * @param int $length
	 *
	 * @return int
	 */
	private function readBinData($bin, $length) {
		$data = substr($bin, $this->readBinDataOffset, $length);
		$this->readBinDataOffset += $length;

		return bindec($data);
	}

	/**
	 * @param int $index
	 *
	 * @return int|string|false
	 */
	public static function bitrateLookup($index) {
		static $lookup = array(
			0  => 32000,
			1  => 56000,
			2  => 64000,
			3  => 96000,
			4  => 112000,
			5  => 128000,
			6  => 192000,
			7  => 224000,
			8  => 256000,
			9  => 320000,
			10 => 384000,
			11 => 448000,
			12 => 512000,
			13 => 576000,
			14 => 640000,
			15 => 768000,
			16 => 960000,
			17 => 1024000,
			18 => 1152000,
			19 => 1280000,
			20 => 1344000,
			21 => 1408000,
			22 => 1411200,
			23 => 1472000,
			24 => 1536000,
			25 => 1920000,
			26 => 2048000,
			27 => 3072000,
			28 => 3840000,
			29 => 'open',
			30 => 'variable',
			31 => 'lossless',
		);
		return (isset($lookup[$index]) ? $lookup[$index] : false);
	}

	/**
	 * @param int $index
	 *
	 * @return int|string|false
	 */
	public static function sampleRateLookup($index) {
		static $lookup = array(
			0  => 'invalid',
			1  => 8000,
			2  => 16000,
			3  => 32000,
			4  => 'invalid',
			5  => 'invalid',
			6  => 11025,
			7  => 22050,
			8  => 44100,
			9  => 'invalid',
			10 => 'invalid',
			11 => 12000,
			12 => 24000,
			13 => 48000,
			14 => 'invalid',
			15 => 'invalid',
		);
		return (isset($lookup[$index]) ? $lookup[$index] : false);
	}

	/**
	 * @param int $index
	 *
	 * @return int|false
	 */
	public static function bitPerSampleLookup($index) {
		static $lookup = array(
			0  => 16,
			1  => 20,
			2  => 24,
			3  => 24,
		);
		return (isset($lookup[$index]) ? $lookup[$index] : false);
	}

	/**
	 * @param int $index
	 *
	 * @return int|false
	 */
	public static function numChannelsLookup($index) {
		switch ($index) {
			case 0:
				return 1;
			case 1:
			case 2:
			case 3:
			case 4:
				return 2;
			case 5:
			case 6:
				return 3;
			case 7:
			case 8:
				return 4;
			case 9:
				return 5;
			case 10:
			case 11:
			case 12:
				return 6;
			case 13:
				return 7;
			case 14:
			case 15:
				return 8;
		}
		return false;
	}

	/**
	 * @param int $index
	 *
	 * @return string
	 */
	public static function channelArrangementLookup($index) {
		static $lookup = array(
			0  => 'A',
			1  => 'A + B (dual mono)',
			2  => 'L + R (stereo)',
			3  => '(L+R) + (L-R) (sum-difference)',
			4  => 'LT + RT (left and right total)',
			5  => 'C + L + R',
			6  => 'L + R + S',
			7  => 'C + L + R + S',
			8  => 'L + R + SL + SR',
			9  => 'C + L + R + SL + SR',
			10 => 'CL + CR + L + R + SL + SR',
			11 => 'C + L + R+ LR + RR + OV',
			12 => 'CF + CR + LF + RF + LR + RR',
			13 => 'CL + C + CR + L + R + SL + SR',
			14 => 'CL + CR + L + R + SL1 + SL2 + SR1 + SR2',
			15 => 'CL + C+ CR + L + R + SL + S + SR',
		);
		return (isset($lookup[$index]) ? $lookup[$index] : 'user-defined');
	}

	/**
	 * @param int $index
	 * @param int $version
	 *
	 * @return int|false
	 */
	public static function dialogNormalization($index, $version) {
		switch ($version) {
			case 7:
				return 0 - $index;
			case 6:
				return 0 - 16 - $index;
		}
		return false;
	}

}