Analysis

Tap a signal with an AnalyserNode, a tap that plays nothing, and these hooks turn it into a live source a component repaints from, with no React render per frame.

Levels

useAudioLevels turns one analyser per channel into what a Meter paints: a level in dB that rises at once and falls at a release rate, and a peak that holds for a moment before it falls, as a live source.

Usage and API: useAudioLevels.

Spectrum

useSpectrum reads an analyser into a spectrum on a log frequency axis, in dB, as a live source a Plot draws, and useSpectrumPeaks holds its peaks and lets them fall.

Usage and API: useSpectrum.

Loudness

loudness measures a whole sound the way streaming services and broadcasters do (ITU-R BS.1770): its integrated loudness in LUFS, its loudest sample, and its true peak, the loudest point of the waveform between the samples. loudnessGain is the gain that brings it to a target as far as its true peak stays under a ceiling, -1 dBTP unless told otherwise: a sound that would pass it lands under the target instead, and nothing is limited.

Usage and API: loudness.

The functions behind them

@audio-ui/engine/analysis holds the math as plain functions, for an engine of your own or a worker:

• rmsDb(samples): The RMS level of samples, in dBFS: how loud they sound.
• peakDb(samples): The level of their loudest sample, in dBFS: how near they come to clipping.
• dbToGain(db), gainToDb(gain): dB and gain, both ways.
• logSpectrum(bins, sampleRate, out, { minHz, maxHz }): An analyser's bins on a log frequency axis, written into out.
• holdPeaks(spectrum, peaks, holding, elapsed, { hold, fall }): Held peaks, a frame at a time.
• computePeaks(channels, buckets): A waveform's peaks, for a Waveform.
• formatDb(db), formatHz(hz): A level and a frequency as text, such as "-6.0 dB" and "1.2 kHz".
• biquadResponse, eqResponse, compressorOutput: What a filter, an equalizer and a compressor do, to draw their curves.