getid3_ogg::ParseOpusPageHeader( string $filedata, int $filedataoffset, array $oggpageinfo ): bool

Compatibility

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

Parameters

$filedatastring

$filedataoffsetint

$oggpageinfoarray

Return value

bool

Performance profile

How much work a call to getid3_ogg::ParseOpusPageHeader() 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

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

46–122

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 130.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

1

1 place in core call this, so the cost is paid more often than your own code shows.

What one call costs · 3 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost getid3_ogg::ParseOpusPageHeader() can have, taken from its control-flow graph on PHP 8.5.

Uses · 2

• getid3_lib::LittleEndian2Int()
• getid3_ogg::error()

Used by · 1

• getid3_ogg::Analyze()

Source code

View on Trac ↗View on GitHub ↗

483	public function ParseOpusPageHeader(&$filedata, &$filedataoffset, &$oggpageinfo) {484		$info = &$this->getid3->info;485		$info['audio']['dataformat']   = 'opus';486		$info['mime_type']             = 'audio/ogg; codecs=opus';487 488		/** @todo find a usable way to detect abr (vbr that is padded to be abr) */489		$info['audio']['bitrate_mode'] = 'vbr';490 491		$info['audio']['lossless']     = false;492 493		$info['ogg']['pageheader']['opus']['opus_magic'] = substr($filedata, $filedataoffset, 8); // hard-coded to 'OpusHead'494		$filedataoffset += 8;495		$info['ogg']['pageheader']['opus']['version']    = getid3_lib::LittleEndian2Int(substr($filedata, $filedataoffset,  1));496		$filedataoffset += 1;497 498		if ($info['ogg']['pageheader']['opus']['version'] < 1 || $info['ogg']['pageheader']['opus']['version'] > 15) {499			$this->error('Unknown opus version number (only accepting 1-15)');500			return false;501		}502 503		$info['ogg']['pageheader']['opus']['out_channel_count'] = getid3_lib::LittleEndian2Int(substr($filedata, $filedataoffset,  1));504		$filedataoffset += 1;505 506		if ($info['ogg']['pageheader']['opus']['out_channel_count'] == 0) {507			$this->error('Invalid channel count in opus header (must not be zero)');508			return false;509		}510 511		$info['ogg']['pageheader']['opus']['pre_skip'] = getid3_lib::LittleEndian2Int(substr($filedata, $filedataoffset,  2));512		$filedataoffset += 2;513 514		$info['ogg']['pageheader']['opus']['input_sample_rate'] = getid3_lib::LittleEndian2Int(substr($filedata, $filedataoffset,  4));515		$filedataoffset += 4;516 517		//$info['ogg']['pageheader']['opus']['output_gain'] = getid3_lib::LittleEndian2Int(substr($filedata, $filedataoffset,  2));518		//$filedataoffset += 2;519 520		//$info['ogg']['pageheader']['opus']['channel_mapping_family'] = getid3_lib::LittleEndian2Int(substr($filedata, $filedataoffset,  1));521		//$filedataoffset += 1;522 523		$info['opus']['opus_version']       = $info['ogg']['pageheader']['opus']['version'];524		$info['opus']['sample_rate_input']  = $info['ogg']['pageheader']['opus']['input_sample_rate'];525		$info['opus']['out_channel_count']  = $info['ogg']['pageheader']['opus']['out_channel_count'];526 527		$info['audio']['channels']          = $info['opus']['out_channel_count'];528		$info['audio']['sample_rate_input'] = $info['opus']['sample_rate_input'];529		$info['audio']['sample_rate']       = 48000; // "All Opus audio is coded at 48 kHz, and should also be decoded at 48 kHz for playback (unless the target hardware does not support this sampling rate). However, this field may be used to resample the audio back to the original sampling rate, for example, when saving the output to a file." -- https://mf4.xiph.org/jenkins/view/opus/job/opusfile-unix/ws/doc/html/structOpusHead.html530		return true;531	}

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.ogg.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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