# LoudnessEBUR128¶

standard mode | Loudness/dynamics category

## Inputs¶

`signal`

(vector_stereosample) - the input stereo audio signal

## Outputs¶

`momentaryLoudness`

(vector_real) - momentary loudness (over 400ms) (LUFS)

`shortTermLoudness`

(vector_real) - short-term loudness (over 3 seconds) (LUFS)

`integratedLoudness`

(real) - integrated loudness (overall) (LUFS)

`loudnessRange`

(real) - loudness range over an arbitrary long time interval [3] (dB, LU)

## Parameters¶

`hopSize`

(real ∈ (0, 0.1], default = 0.1) :the hop size with which the loudness is computed [s]

`sampleRate`

(real ∈ (0, ∞), default = 44100) :the sampling rate of the audio signal [Hz]

`startAtZero`

(bool ∈ {true, false}, default = false) :start momentary/short-term loudness estimation at time 0 (zero-centered loudness estimation windows) if true; otherwise start both windows at time 0 (time positions for momentary and short-term values will not be syncronized)

## Description¶

This algorithm computes the EBU R128 loudness descriptors of an audio signal.

The input stereo signal is preprocessed with a K-weighting filter [2] (see LoudnessEBUR128Filter algorithm), composed of two stages: a shelving filter and a high-pass filter (RLB-weighting curve).

Momentary loudness is computed by integrating the sum of powers over a sliding rectangular window of 400 ms. The measurement is not gated.

Short-term loudness is computed by integrating the sum of powers over a sliding rectangular window of 3 seconds. The measurement is not gated.

Integrated loudness is a loudness value averaged over an arbitrary long time interval with gating of 400 ms blocks with two thresholds [2].

Absolute ‘silence’ gating threshold at -70 LUFS for the computation of the absolute-gated loudness level.

Relative gating threshold, 10 LU below the absolute-gated loudness level.

Loudness range is computed from short-term loudness values. It is defined as the difference between the estimates of the 10th and 95th percentiles of the distribution of the loudness values with applied gating [3].

Absolute ‘silence’ gating threshold at -70 LUFS for the computation of the absolute-gated loudness level.

Relative gating threshold, -20 LU below the absolute-gated loudness level.

- References:
[1] EBU Tech 3341-2011. “Loudness Metering: ‘EBU Mode’ metering to supplement loudness normalisation in accordance with EBU R 128”

[2] ITU-R BS.1770-2. “Algorithms to measure audio programme loudness and true-peak audio level”

[3] EBU Tech Doc 3342-2011. “Loudness Range: A measure to supplement loudness normalisation in accordance with EBU R 128”

[4] https://tech.ebu.ch/loudness

## Source code¶

## See also¶

Loudness (standard) Loudness (streaming) LoudnessEBUR128 (streaming) LoudnessEBUR128Filter (streaming) Meter (standard) Meter (streaming)