getid3_dts::Analyze(): bool

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Return value

bool

Performance profile

How much work a call to getid3_dts::Analyze() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Moderate

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with how much data it finds.

Instructions

49–416

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 493.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What one call costs · 5 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost getid3_dts::Analyze() can have, taken from its control-flow graph on PHP 8.5.

Uses · 13

• getid3_dts::fseek()
• getid3_dts::fread()
• getid3_dts::isDependencyFor()
• getid3_dts::error()
• getid3_lib::PrintHexBytes()
• getid3_lib::BigEndian2Bin()
• getid3_dts::readBinData()
• getid3_dts::bitrateLookup()
• getid3_dts::bitPerSampleLookup()
• getid3_dts::sampleRateLookup()
• getid3_dts::dialogNormalization()
• getid3_dts::numChannelsLookup()

Source code

View on Trac ↗View on GitHub ↗

48	public function Analyze() {49		$info = &$this->getid3->info;50		$info['fileformat'] = 'dts';51 52		$this->fseek($info['avdataoffset']);53		$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 bytes54 55		// check syncword56		$sync = substr($DTSheader, 0, 4);57		if (($encoding = array_search($sync, self::$syncwords)) !== false) {58 59			$info['dts']['raw']['magic'] = $sync;60			$this->readBinDataOffset = 32;61 62		} elseif ($this->isDependencyFor('matroska')) {63 64			// Matroska contains DTS without syncword encoded as raw big-endian format65			$encoding = 0;66			$this->readBinDataOffset = 0;67 68		} else {69 70			unset($info['fileformat']);71			return $this->error('Expecting "'.implode('| ', array_map('getid3_lib::PrintHexBytes', self::$syncwords)).'" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes($sync).'"');72 73		}74 75		// decode header76		$fhBS = '';77		for ($word_offset = 0; $word_offset <= strlen($DTSheader); $word_offset += 2) {78			switch ($encoding) {79				case 0: // raw big-endian80					$fhBS .=        getid3_lib::BigEndian2Bin(       substr($DTSheader, $word_offset, 2) );81					break;82				case 1: // raw little-endian83					$fhBS .=        getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2)));84					break;85				case 2: // 14-bit big-endian86					$fhBS .= substr(getid3_lib::BigEndian2Bin(       substr($DTSheader, $word_offset, 2) ), 2, 14);87					break;88				case 3: // 14-bit little-endian89					$fhBS .= substr(getid3_lib::BigEndian2Bin(strrev(substr($DTSheader, $word_offset, 2))), 2, 14);90					break;91			}92		}93 94		$info['dts']['raw']['frame_type']             =        $this->readBinData($fhBS,  1);95		$info['dts']['raw']['deficit_samples']        =        $this->readBinData($fhBS,  5);96		$info['dts']['flags']['crc_present']          = (bool) $this->readBinData($fhBS,  1);97		$info['dts']['raw']['pcm_sample_blocks']      =        $this->readBinData($fhBS,  7);98		$info['dts']['raw']['frame_byte_size']        =        $this->readBinData($fhBS, 14);99		$info['dts']['raw']['channel_arrangement']    =        $this->readBinData($fhBS,  6);100		$info['dts']['raw']['sample_frequency']       =        $this->readBinData($fhBS,  4);101		$info['dts']['raw']['bitrate']                =        $this->readBinData($fhBS,  5);102		$info['dts']['flags']['embedded_downmix']     = (bool) $this->readBinData($fhBS,  1);103		$info['dts']['flags']['dynamicrange']         = (bool) $this->readBinData($fhBS,  1);104		$info['dts']['flags']['timestamp']            = (bool) $this->readBinData($fhBS,  1);105		$info['dts']['flags']['auxdata']              = (bool) $this->readBinData($fhBS,  1);106		$info['dts']['flags']['hdcd']                 = (bool) $this->readBinData($fhBS,  1);107		$info['dts']['raw']['extension_audio']        =        $this->readBinData($fhBS,  3);108		$info['dts']['flags']['extended_coding']      = (bool) $this->readBinData($fhBS,  1);109		$info['dts']['flags']['audio_sync_insertion'] = (bool) $this->readBinData($fhBS,  1);110		$info['dts']['raw']['lfe_effects']            =        $this->readBinData($fhBS,  2);111		$info['dts']['flags']['predictor_history']    = (bool) $this->readBinData($fhBS,  1);112		if ($info['dts']['flags']['crc_present']) {113			$info['dts']['raw']['crc16']              =        $this->readBinData($fhBS, 16);114		}115		$info['dts']['flags']['mri_perfect_reconst']  = (bool) $this->readBinData($fhBS,  1);116		$info['dts']['raw']['encoder_soft_version']   =        $this->readBinData($fhBS,  4);117		$info['dts']['raw']['copy_history']           =        $this->readBinData($fhBS,  2);118		$info['dts']['raw']['bits_per_sample']        =        $this->readBinData($fhBS,  2);119		$info['dts']['flags']['surround_es']          = (bool) $this->readBinData($fhBS,  1);120		$info['dts']['flags']['front_sum_diff']       = (bool) $this->readBinData($fhBS,  1);121		$info['dts']['flags']['surround_sum_diff']    = (bool) $this->readBinData($fhBS,  1);122		$info['dts']['raw']['dialog_normalization']   =        $this->readBinData($fhBS,  4);123 124 125		$info['dts']['bitrate']              = self::bitrateLookup($info['dts']['raw']['bitrate']);126		$info['dts']['bits_per_sample']      = self::bitPerSampleLookup($info['dts']['raw']['bits_per_sample']);127		$info['dts']['sample_rate']          = self::sampleRateLookup($info['dts']['raw']['sample_frequency']);

Changelog

Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/ID3/module.audio.dts.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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