µ-spectrum-heatmap

Heat map spectrum analyzer for WebAudio.

Install

npm i uspectrum-heatmap

Usage

import USpectrumHeatmap from 'uspectrum-heatmap'

const spectrum = new USpectrumHeatmap({ context, buffer, source, canvas })
spectrum
  .init({ context: AudioContext, buffer: AudioBuffer, source: AudioSource })
  .render()

Constructor

All params are optional.

• context: An AudioContext object.
• buffer: An AudioBuffer object.
• source: An AudioBufferSourceSource object.
• canvas: Can be:
  • A CSS selector pointing to a canvas element rendered on the page.
  • A reference to a canvas element.
  • Unset: a canvas element will be created an appended to body.

Methods

• init({ context, buffer, source }): Initializes audio analyzer and connects it to audio source. See Constructor for signature reference. Allows chaining.
• render: Requests animation frame and starts rendering audio data with buffer updates.
• setFftSize(size): Sets fftSize property on AnalyzerNode. Default is 2048.
• setMinDb(db): Sets minDecibels property on AnalyzerNode. Default is -90.
• setMaxDb(db): Sets maxDecibels property on AnalyzerNode. Default is -10.
• setSmoothing(smoothing): Sets smoothingTimeConstant on AnalyzerNode. Default is 0.85.
• setRenderRatio(ratio): A ratio of 1 means rendering using all the available width, which might be really costly. Default is 16. Try bigger values to optimize rendering performance. Try lower values for longer spectrum visibility.
• setSize(): Automatically called when window is resized to recalculate rendering area.

Usage with µ-player

µ-player is a WebAudio based programatic player that plays well with µ-spectrum-heatmap.

import Player from 'uplayer'

const player = new Player('https://some.mp3')
player
  .on('play', () => {
    spectrum
      .init({ context: player.context, buffer: player.buffer, source: player.source })
      .render()
  })
  .load()
  .play()