# LoudnessEBUR128

streaming mode | Loudness/dynamics category

## Inputs

signal(stereosample) - the input stereo audio signal

## Outputs

momentaryLoudness(real) - momentary loudness (over 400ms) (LUFS)shortTermLoudness(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]

## 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"