API

Complete API documentation for VERO-BAAMBI metering modules.

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Metering Modules

LUFSMeter

EBU R128 / ITU-R BS.1770-4 loudness measurement.

import { LUFSMeter } from './src/metering/lufs.js';

const meter = new LUFSMeter({ sampleRate: 48000 });

Constructor Options

Option	Type	Default	Description
sampleRate	number	48000	Audio sample rate in Hz

Methods

update(leftBuffer, rightBuffer)

Process audio samples through K-weighting filter and update loudness values.

• leftBuffer: Float32Array - Left channel samples
• rightBuffer: Float32Array - Right channel samples

getState() → LUFSMeterState

Returns current loudness readings:

{
  momentary: number,   // 400ms window (LUFS)
  shortTerm: number,   // 3s window (LUFS)
  integrated: number,  // Programme-length gated (LUFS)
  lra: number          // Loudness Range (LU)
}

reset()

Reset all measurements and history.

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TruePeakMeter

ITU-R BS.1770-4 Annex 2 intersample peak detection with 4× Hermite interpolation.

import { TruePeakMeter } from './src/metering/true-peak.js';

const meter = new TruePeakMeter({
  sampleRate: 48000,
  peakHoldSeconds: 3,
  limit: -1  // dBTP
});

Constructor Options

Option	Type	Default	Description
sampleRate	number	48000	Audio sample rate in Hz
peakHoldSeconds	number	3	Peak hold duration
limit	number	-1	Over-limit threshold (dBTP)

Methods

update(leftBuffer, rightBuffer)

Process audio samples and detect intersample peaks.

getState() → TruePeakMeterState

{
  dbtpLeft: number,      // Current left True Peak (dBTP)
  dbtpRight: number,     // Current right True Peak (dBTP)
  dbtpHoldLeft: number,  // Peak hold left (dBTP, 3s)
  dbtpHoldRight: number, // Peak hold right (dBTP, 3s)
  dbtpMax: number,       // Maximum since reset (dBTP)
  isOverLeft: boolean,   // Left exceeded limit
  isOverRight: boolean,  // Right exceeded limit
  isOverAny: boolean     // Either channel exceeded limit
}

reset()

Reset peak hold and over indicator.

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PPMMeter

IEC 60268-10 Type I (Nordic) quasi-peak programme meter.

import { PPMMeter } from './src/metering/ppm.js';

const meter = new PPMMeter({
  sampleRate: 48000,
  peakHoldSeconds: 3,
  useRCDetector: true
});

Constructor Options

Option	Type	Default	Description
sampleRate	number	48000	Audio sample rate in Hz
peakHoldSeconds	number	3	Peak hold duration
useRCDetector	boolean	true	Use RC detector (analogue-accurate)

Methods

update(leftBuffer, rightBuffer)

Process audio samples through quasi-peak detector.

getState() → PPMMeterState

{
  dbfsLeft: number,         // Current left level (dBFS)
  dbfsRight: number,        // Current right level (dBFS)
  dbfsHoldLeft: number,     // Peak hold left (dBFS, 3s)
  dbfsHoldRight: number,    // Peak hold right (dBFS, 3s)
  ppmScaleLeft: number,     // Current left (Nordic PPM, -36 to +9)
  ppmScaleRight: number,    // Current right (Nordic PPM)
  ppmScaleHoldLeft: number, // Peak hold left (Nordic PPM)
  ppmScaleHoldRight: number,// Peak hold right (Nordic PPM)
  isSilentLeft: boolean,    // Left below scale minimum
  isSilentRight: boolean    // Right below scale minimum
}

resetPeakHold()

Reset peak hold values only.

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StereoMeter

Phase correlation, balance, and stereo width analysis.

import { StereoMeter } from './src/metering/correlation.js';

const meter = new StereoMeter({ smoothingMs: 100 });

Constructor Options

Option	Type	Default	Description
smoothingMs	number	100	Display smoothing in ms

Methods

update(leftBuffer, rightBuffer)

Calculate correlation, balance, and width.

getState() → StereoMeterState

{
  correlation: number,        // -1 to +1 (smoothed)
  correlationInstant: number, // -1 to +1 (instantaneous)
  balance: number,            // -1 (left) to +1 (right)
  width: number,              // 0 (mono) to 1+ (wide)
  zone: string                // 'good' | 'caution' | 'problem'
}

reset()

Reset meter state.

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Utility Functions

dB Conversions

import { gainToDb, dbToGain } from './src/utils/math.js';

gainToDb(0.5);   // → -6.02 dB
dbToGain(-6);    // → 0.501

PPM Scale Conversion

import { dbfsToPPM, ppmToDbfs } from './src/metering/ppm.js';

dbfsToPPM(-18);  // → 0 PPM (EBU alignment)
ppmToDbfs(6);    // → -12 dBFS (TEST level)

Correlation Colour

import { getCorrelationColour } from './src/metering/correlation.js';

getCorrelationColour(0.8);   // → '#00d4aa' (green, good)
getCorrelationColour(-0.5);  // → '#ff4444' (red, phase issue)

M/S Conversion

import { lrToMs, msToLr } from './src/metering/correlation.js';

const { mid, side } = lrToMs(leftSample, rightSample);
const { left, right } = msToLr(mid, side);

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Constants

Loudness Standards

import {
  DEFAULT_TARGET_LUFS,  // -23 (EBU R128)
  TP_LIMIT_EBU,         // -1 dBTP
  TP_LIMIT_STREAMING    // -2 dBTP (codec headroom)
} from './src/metering/index.js';

PPM Scale

import {
  PPM_MIN_DBFS,  // -60 dBFS (scale minimum)
  PPM_MAX_DBFS,  // -9 dBFS (+9 PPM / PML)
  PPM_TEST_DBFS  // -12 dBFS (+6 PPM / TEST)
} from './src/metering/ppm.js';

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Type Definitions

All types are documented with JSDoc and available for TypeScript validation:

npx tsc --noEmit --allowJs --checkJs --strict src/metering/*.js

See individual module files for complete @typedef declarations.

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Remote Module

validateBrokerUrl

Validate and normalise a broker WebSocket URL.

import { validateBrokerUrl } from './src/remote/index.js';

const result = validateBrokerUrl('ws://localhost:8765');
// → { valid: true, normalized: 'ws://localhost:8765' }

const invalid = validateBrokerUrl('http://localhost');
// → { valid: false, error: 'Broker URL must start with ws:// or wss://' }

ProbeSender

Send metrics to a broker.

import { ProbeSender } from './src/remote/index.js';

const probe = new ProbeSender({
  name: 'Studio A',
  brokerUrl: 'ws://broker.local:8765'
});

probe.collector.setSources({ lufsMeter, truePeakMeter, ppmMeter });
await probe.start();

MetricsReceiver

Receive metrics from probes via broker.

import { MetricsReceiver } from './src/remote/index.js';

const receiver = new MetricsReceiver({ brokerUrl: 'ws://broker.local:8765' });
receiver.onMetrics((probeId, metrics) => updateDisplay(metrics));
await receiver.connect();
receiver.subscribe('probe-uuid');

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Generated for VERO-BAAMBI v2.3.0 (unreleased)