<?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;
}

}