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    Class AudioAnalyser

    Helper for doing audio analysis. It takes case of connecting the audio stream, running in a loop and pause capability.

    Provide a function which works with an AnalyserNode, and does something with the result.

    const myAnalysis = (node, analyser) => {
     const freq = new Float32Array(node.frequencyBinCount);
     node.getFloatFrequencyData(freq);
     // Do something with frequency data...
    }
    const a = new Analyser(myAnalysis);

    Helper functions provide ready-to-use Analysers:

    Note: Browers won't allow microphone access unless the call has come from a user-interaction, eg pointerup event handler.

    Constructors

    constructor

    Properties

    analyse analyserNode audioCtx debug fftSize showVis smoothingTimeConstant visualiser

    Accessors

    paused

    Methods

    getFrequencyAtIndex getFrequencyRangeMax getIndexForFrequency init sliceByFrequency

    Constructors

    constructor

    Properties

    analyse

    analyse: DataAnalyser

    analyserNode

    analyserNode: undefined | AnalyserNode

    audioCtx

    audioCtx: undefined | AudioContext

    debug

    debug: boolean

    fftSize

    fftSize: number

    showVis

    showVis: boolean

    smoothingTimeConstant

    smoothingTimeConstant: number

    visualiser

    visualiser: undefined | AudioVisualiser

    Accessors

    paused

    • get paused(): boolean

      Returns boolean

    • set paused(v: boolean): void

      Parameters

      • v: boolean

      Returns void

    Methods

    getFrequencyAtIndex

    • getFrequencyAtIndex(index: number): number

      Returns the starting frequency for a given binned frequency index.

      Parameters

      • index: number

        Array index

      Returns number

      Sound frequency

    getFrequencyRangeMax

    • getFrequencyRangeMax(
          lowFreq: number,
          highFreq: number,
          freqData: readonly number[],
      ): number

      Returns the maximum FFT value within the given frequency range

      Parameters

      • lowFreq: number
      • highFreq: number
      • freqData: readonly number[]

      Returns number

    getIndexForFrequency

    • getIndexForFrequency(freq: number): number

      Returns a binned array index for a given frequency

      Parameters

      • freq: number

        Sound frequency

      Returns number

      Array index into frequency bins

    init

    • init(): void

      Returns void

    sliceByFrequency

    • sliceByFrequency(
          lowFreq: number,
          highFreq: number,
          freqData: readonly number[],
      ): number[]

      Returns a sub-sampling of frequency analysis data that falls between lowFreq and highFreq.

      Parameters

      • lowFreq: number

        Low frequency

      • highFreq: number

        High frequency

      • freqData: readonly number[]

        Full-spectrum frequency data

      Returns number[]

      Sub-sampling of analysis

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