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