mirror of
https://github.com/Tonejs/Tone.js
synced 2024-12-28 12:33:12 +00:00
92 lines
2.8 KiB
TypeScript
92 lines
2.8 KiB
TypeScript
import { ToneAudioNode } from "../../core/context/ToneAudioNode";
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import { dbToGain } from "../../core/type/Conversions";
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import { Hertz, NormalRange, PowerOfTwo } from "../../core/type/Units";
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import { optionsFromArguments } from "../../core/util/Defaults";
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import { MeterBase, MeterBaseOptions } from "./MeterBase";
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import { assert } from "../../core/util/Debug";
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export interface FFTOptions extends MeterBaseOptions {
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size: PowerOfTwo;
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smoothing: NormalRange;
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normalRange: boolean;
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}
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/**
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* Get the current frequency data of the connected audio source using a fast Fourier transform.
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* @category Component
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*/
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export class FFT extends MeterBase<FFTOptions> {
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readonly name: string = "FFT";
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/**
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* If the output should be in decibels or normal range between 0-1. If `normalRange` is false,
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* the output range will be the measured decibel value, otherwise the decibel value will be converted to
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* the range of 0-1
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*/
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normalRange: boolean;
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/**
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* @param size The size of the FFT. Value must be a power of two in the range 16 to 16384.
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*/
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constructor(size?: PowerOfTwo);
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constructor(options?: Partial<FFTOptions>);
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constructor() {
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super(optionsFromArguments(FFT.getDefaults(), arguments, ["size"]));
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const options = optionsFromArguments(FFT.getDefaults(), arguments, ["size"]);
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this.normalRange = options.normalRange;
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this._analyser.type = "fft";
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this.size = options.size;
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}
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static getDefaults(): FFTOptions {
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return Object.assign(ToneAudioNode.getDefaults(), {
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normalRange: false,
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size: 1024,
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smoothing: 0.8,
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});
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}
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/**
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* Gets the current frequency data from the connected audio source.
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* Returns the frequency data of length [[size]] as a Float32Array of decibel values.
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*/
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getValue(): Float32Array {
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const values = this._analyser.getValue() as Float32Array;
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return values.map(v => this.normalRange ? dbToGain(v) : v);
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}
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/**
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* The size of analysis. This must be a power of two in the range 16 to 16384.
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* Determines the size of the array returned by [[getValue]] (i.e. the number of
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* frequency bins). Large FFT sizes may be costly to compute.
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*/
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get size(): PowerOfTwo {
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return this._analyser.size;
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}
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set size(size) {
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this._analyser.size = size;
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}
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/**
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* 0 represents no time averaging with the last analysis frame.
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*/
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get smoothing(): NormalRange {
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return this._analyser.smoothing;
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}
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set smoothing(val) {
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this._analyser.smoothing = val;
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}
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/**
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* Returns the frequency value in hertz of each of the indices of the FFT's [[getValue]] response.
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* @example
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* const fft = new Tone.FFT(32);
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* console.log([0, 1, 2, 3, 4].map(index => fft.getFrequencyOfIndex(index)));
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*/
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getFrequencyOfIndex(index: number): Hertz {
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assert(0 <= index && index < this.size, `index must be greater than or equal to 0 and less than ${this.size}`);
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return index * this.context.sampleRate / (this.size * 2);
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}
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}
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