---
title: Loudness and dynamics
order: 5
summary: Measure loudness the EBU R128 way, master to a target, compress, limit and equalize.
---

<!-- Generated by tools/generate-docs.bxs from the BIF classes. Do not edit; change the Javadoc and run it again. -->

Measure loudness the EBU R128 way, master to a target, compress, limit and equalize.

## audioLoudness

Measure the loudness of audio as EBU R128 does: integrated LUFS, loudness range, true peak

```js
audioLoudness( audio )
```

| Argument | Type | Default | |
|---|---|---|---|
| `audio` | any | required | The audio buffer. |

**Returns** A struct with integrated (LUFS, gated, the number streaming services use), range (LU), truePeakDb and samplePeakDb (dBFS), momentaryMax and shortTermMax (LUFS). Silence or audio shorter than 400 ms reads -120.

## audioNormalizeLoudness

Set the integrated loudness of audio to a target in LUFS, keeping peaks under a true-peak ceiling

```js
audioNormalizeLoudness( audio, targetLufs=-14, truePeakDb=-1 )
```

| Argument | Type | Default | |
|---|---|---|---|
| `audio` | any | required | The audio buffer. |
| `targetLufs` | double | `-14` | The loudness to reach. -14 suits streaming and video platforms, -16 podcasts, -23 broadcast (EBU R128). Defaults to -14. |
| `truePeakDb` | double | `-1` | The highest peak allowed in dBFS. A limiter catches what the gain pushes over it. Defaults to -1. |

**Returns** A new audio buffer.

## audioMaster

Master audio for delivery: reach a loudness target with a true-peak ceiling, optionally gluing the mix with light compression

```js
audioMaster( audio, target="streaming", truePeakDb=-1, glue=false )
```

| Argument | Type | Default | |
|---|---|---|---|
| `audio` | any | required | The audio buffer. |
| `target` | any | `"streaming"` | A preset name or a number in LUFS. streaming is -14, podcast -16, game -16, broadcast -23 (EBU R128), cinema -24. Defaults to streaming. |
| `truePeakDb` | double | `-1` | The highest peak in dBFS. Defaults to -1. |
| `glue` | boolean | `false` | True to compress lightly (2:1, slow) before normalizing so the mix sounds more even. Defaults to false. |

**Returns** A new audio buffer.

## audioCompress

Reduce the dynamic range of audio with a compressor

```js
audioCompress( audio, thresholdDb=-18, ratio=4, attackMs=10, releaseMs=100, knee=6, makeupDb="auto" )
```

| Argument | Type | Default | |
|---|---|---|---|
| `audio` | any | required | The audio buffer. |
| `thresholdDb` | double | `-18` | Level above which the audio is turned down, in dB. Defaults to -18. |
| `ratio` | double | `4` | How strongly: 4 means 4 dB over the threshold becomes 1 dB. Defaults to 4. |
| `attackMs` | double | `10` | Milliseconds to turn down. Defaults to 10. |
| `releaseMs` | double | `100` | Milliseconds to turn back up. Defaults to 100. |
| `knee` | double | `6` | Width in dB of the soft knee. 0 is a hard knee. Defaults to 6. |
| `makeupDb` | any | `"auto"` | Gain added after compression in dB, or "auto" to match the loudness (RMS) of the input. Defaults to auto. |

**Returns** A new audio buffer.

## audioLimit

Stop audio from going above a ceiling with a look-ahead limiter

```js
audioLimit( audio, ceilingDb=-1, releaseMs=100, lookAheadMs=5 )
```

| Argument | Type | Default | |
|---|---|---|---|
| `audio` | any | required | The audio buffer. |
| `ceilingDb` | double | `-1` | The highest level in dB, at most 0, counting the peaks between the samples (the true peak). Defaults to -1. |
| `releaseMs` | double | `100` | Milliseconds to recover after a peak. Defaults to 100. |
| `lookAheadMs` | double | `5` | Milliseconds the limiter looks ahead. Defaults to 5. |

**Returns** A new audio buffer.

## audioEq

Shape the tone of audio with parametric equalizer bands

```js
audioEq( audio, bands )
```

| Argument | Type | Default | |
|---|---|---|---|
| `audio` | any | required | The audio buffer. |
| `bands` | array | required | An array of structs, each with type (peak, lowshelf, highshelf, lowpass, highpass or notch), freq in Hz, gainDb in dB (peak and shelves) and optionally q (width, default 1 for a peak and 0.707 for others). |

**Returns** A new audio buffer.