@audio/loudness-lra

Loudness range (LRA) — EBU Tech 3342 short-term distribution, P95−P10 after gating

npm install @audio/loudness-lra

import lra from '@audio/loudness-lra'

Loudness range per EBU Tech 3342: K-weighted (via @audio/weighting-k) channel-summed short-term loudness on a 3 s window at 100 ms hop → absolute gate at −70 LUFS → relative gate at −20 LU below the abs-gated mean → LRA = P95 − P10 of the remaining distribution, in LU.

let range = lra(channels, { fs: 48000 })   // channels: Float32Array (mono) or Float32Array[] (multichannel)

| Param | Default | | |---|---|---| | fs | 48000 | Sample rate, Hz | | weights | BS.1770-4 Table 1 | Per-channel gain array. Defaults by channel count assuming SMPTE/WAV/Web Audio order: 1/2ch all 1.0, 4ch [1,1,1.41,1.41], 5ch [1,1,1,1.41,1.41], 6ch [1,1,1,0,1.41,1.41] (LFE excluded). Other counts default to 1.0 per channel — pass explicitly for layouts in a different order |

Returns a number (LRA in LU), 0 if fewer than 2 blocks survive gating, or null for silence / input shorter than the 3 s short-term window.

Use when: measuring program dynamics for broadcast delivery specs (EBU R128 / ATSC A/85) that cap LRA alongside integrated loudness.

Per ITU-R BS.1770-4 (K-weighting, gating) and EBU Tech 3342 (short-term window, percentile range); differential-tested against libebur128 / ffmpeg ebur128.

Part of @audio/loudness — the loudness family umbrella. Documented from the reference implementation.

MIT © audiojs