This lib wraps the Web Audio API. It is designed to make realtime analysis of a web audio stream (media or microphone) easier. Created it for this project so we can easily react to volume levels and frequency spikes for reactive Canvas/GL visualizations.
Instantiated via new.
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Pumper.start(source, start = 1920, end = 16800, precision = 11)- source can be a media URL or 'mic'
- 'start' and 'end' define the global frequency ranges
- precision will decide how many lookups the analyzer will have
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Pumper.update()- updates all exposed properties with latest data
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Pumper.createBand(start, end, threshold, spikeTolerance, volScale = 1)- creates a new frequency range monitor and returns the instance
- 'start' and 'end' define the band frequency ranges
- frequency range is scaled to global values
- 'volScale' optionally multiplies returned volume values
Exposed properties:
Pumper.bands- array of all Band instances in the order they were createdPumper.volume- current global average volume level. Set via Pumper.update()Pumper.globalSpikeTolerance- distance over which a volume change is considered a spikePumper.globalThreshold- arbitrary threshold value for global volume levelPumper.isSpiking- true if there was a volume spike since the last time update() was calledPumper.isOverThreshold- true if the current global volume exceeds the set global thresholdPumper.freqData- raw frequency data arrayPumper.timeData- raw time domain data array
const pumper = new Pumper()Creates a new instance of the Pumper class.pumper.start('mic', 1160, 14000, 13)Initializes Pumper and uses default audio input as source.pumper.createBands(80, 220, 10, 1, 1.25, 0.5)Create a set of bands (10) over bass frequencies:- Volume of first band is 1x, last band is 1.25x multiplied
- Bleed amount of 0.5 (overlap halfway with each band)
pumper.update()Updates the frequency data of global and band values, and calculates volumepumper.bands[0].volumeVolume of the first bass band we created