Loudness meter per ITU-R BS.1770-4 / EBU R128. More...

#include <gin_loudnessmeter.h>

Public Member Functions
	LoudnessMeter ()=default

void	prepare (double sampleRate, int numChannels, double maxHistorySeconds=24.0 60.0 60.0)
	maxHistorySeconds bounds the memory used for the integrated / range histories (about 40 kB per hour).

void	reset ()
	Clears everything, including the integrated history.

void	process (const juce::AudioBuffer< float > &buffer)
	Audio thread.

float	getMomentary () const

float	getShortTerm () const

float	getMaxMomentary () const

float	getMaxShortTerm () const

float	getIntegrated () const
	Gated integrated loudness since the last reset.

float	getLoudnessRange () const
	Loudness range (EBU Tech 3342) since the last reset, in LU.

double	getElapsedSeconds () const
	Seconds of audio measured since the last reset.

void	setChannelWeight (int channel, float weight)

Static Public Member Functions
static float	powerToLoudness (double power)
	Converts a mean square power to loudness.

static double	loudnessToPower (float loudness)

Static Public Attributes
static constexpr float	silence = -100.0f

Detailed Description

Loudness meter per ITU-R BS.1770-4 / EBU R128.

Call process() from the audio thread. The momentary (400 ms) and short-term (3 s) values are updated every 100 ms and can be read from any thread. Integrated loudness and loudness range are gated measurements over the whole history since the last reset; they are computed on demand from that history by getIntegrated() / getLoudnessRange(), which are intended to be called from the message thread as they do a little work.

Channel weighting follows the standard: 1.0 for the first three channels (L, R, C) and 1.41 for channels 4 and 5 (Ls, Rs).

Values are in LUFS (LU for the range). Below the measurable floor, or before any audio has been processed, getters return silence.

Constructor & Destructor Documentation

◆ LoudnessMeter()

LoudnessMeter::LoudnessMeter ( )

default

Member Function Documentation

◆ prepare()

void LoudnessMeter::prepare	(	double	sampleRate,
		int	numChannels,
		double	maxHistorySeconds = `24.0 60.0 60.0`
	)

maxHistorySeconds bounds the memory used for the integrated / range histories (about 40 kB per hour).

Not realtime safe.

◆ reset()

void LoudnessMeter::reset ( )

Clears everything, including the integrated history.

Safe to call from any thread; takes effect on the next process() call.

◆ process()

void LoudnessMeter::process ( const juce::AudioBuffer< float > & buffer )

Audio thread.

Uses up to the prepared number of channels.

◆ getMomentary()

float LoudnessMeter::getMomentary ( ) const

◆ getShortTerm()

float LoudnessMeter::getShortTerm ( ) const

◆ getMaxMomentary()

float LoudnessMeter::getMaxMomentary ( ) const

◆ getMaxShortTerm()

float LoudnessMeter::getMaxShortTerm ( ) const

◆ getIntegrated()

float LoudnessMeter::getIntegrated ( ) const

Gated integrated loudness since the last reset.

Message thread.

◆ getLoudnessRange()

float LoudnessMeter::getLoudnessRange ( ) const

Loudness range (EBU Tech 3342) since the last reset, in LU.

Message thread.

◆ getElapsedSeconds()

double LoudnessMeter::getElapsedSeconds ( ) const

Seconds of audio measured since the last reset.

◆ setChannelWeight()

void LoudnessMeter::setChannelWeight	(	int	channel,
		float	weight
	)

◆ powerToLoudness()

static float LoudnessMeter::powerToLoudness ( double power )

static

Converts a mean square power to loudness.

◆ loudnessToPower()

static double LoudnessMeter::loudnessToPower ( float loudness )