<?php

/////////////////////////////////////////////////////////////////

/// getID3() by James Heinrich <info@getid3.org>               //

//  available at http://getid3.sourceforge.net                 //

//            or http://www.getid3.org                         //

//          also https://github.com/JamesHeinrich/getID3       //

/////////////////////////////////////////////////////////////////

// See readme.txt for more details                             //

/////////////////////////////////////////////////////////////////

//                                                             //

// module.audio.dts.php                                        //

// module for analyzing DTS Audio files                        //

// dependencies: NONE                                          //

//                                                             //

/////////////////////////////////////////////////////////////////

/**

* @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";

	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

	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;

	}

	private function readBinData($bin, $length) {

		$data = substr($bin, $this->readBinDataOffset, $length);

		$this->readBinDataOffset += $length;

		return bindec($data);

	}

	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);

	}

	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);

	}

	public static function bitPerSampleLookup($index) {

		static $lookup = array(

			0  => 16,

			1  => 20,

			2  => 24,

			3  => 24,

		);

		return (isset($lookup[$index]) ? $lookup[$index] : false);

	}

	public static function numChannelsLookup($index) {

		switch ($index) {

			case 0:

				return 1;

				break;

			case 1:

			case 2:

			case 3:

			case 4:

				return 2;

				break;

			case 5:

			case 6:

				return 3;

				break;

			case 7:

			case 8:

				return 4;

				break;

			case 9:

				return 5;

				break;

			case 10:

			case 11:

			case 12:

				return 6;

				break;

			case 13:

				return 7;

				break;

			case 14:

			case 15:

				return 8;

				break;

		}

		return false;

	}

	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');

	}

	public static function dialogNormalization($index, $version) {

		switch ($version) {

			case 7:

				return 0 - $index;

				break;

			case 6:

				return 0 - 16 - $index;

				break;

		}

		return false;

	}

}