Pumper - Web Audio API analysis & monitoring library

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.

Example Projects

API

• 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

• Pumper.update()

  • updates all exposed properties with latest data

• 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 created
• Pumper.volume - current global average volume level. Set via Pumper.update()
• Pumper.globalSpikeTolerance - distance over which a volume change is considered a spike
• Pumper.globalThreshold - arbitrary threshold value for global volume level
• Pumper.isSpiking - true if there was a volume spike since the last time update() was called
• Pumper.isOverThreshold - true if the current global volume exceeds the set global threshold
• Pumper.freqData - raw frequency data array
• Pumper.timeData - raw time domain data array

Examples

• 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 volume
• pumper.bands[0].volume Volume of the first bass band we created