mirror of
https://github.com/Tonejs/Tone.js
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84 lines
2.3 KiB
TypeScript
84 lines
2.3 KiB
TypeScript
import { gainToDb } from "../../core/type/Conversions";
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import { Decibels, NormalRange } 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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export interface MeterOptions extends MeterBaseOptions {
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smoothing: NormalRange;
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}
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/**
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* Meter gets the [RMS](https://en.wikipedia.org/wiki/Root_mean_square)
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* of an input signal. It can also get the raw value of the input signal.
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*
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* @example
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* var meter = new Meter();
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* var mic = new Tone.UserMedia().open();
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* //connect mic to the meter
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* mic.connect(meter);
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* //the current level of the mic input in decibels
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* var level = meter.getLevel();
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*/
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export class Meter extends MeterBase<MeterOptions> {
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readonly name: string = "Meter";
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/**
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* A value from between 0 and 1 where 0 represents no time averaging with the last analysis frame.
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*/
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smoothing: number;
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/**
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* The previous frame's value
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*/
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private _rms = 0;
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/**
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* @param smoothing The amount of smoothing applied between frames.
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*/
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constructor(smoothing?: NormalRange);
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// tslint:disable-next-line: unified-signatures
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constructor(options?: Partial<MeterOptions>);
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constructor() {
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super(optionsFromArguments(Meter.getDefaults(), arguments, ["smoothing"]));
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const options = optionsFromArguments(Meter.getDefaults(), arguments, ["smoothing"]);
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this.smoothing = options.smoothing;
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this._analyser.size = 256;
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this._analyser.type = "waveform";
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}
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static getDefaults(): MeterOptions {
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return Object.assign(MeterBase.getDefaults(), {
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smoothing: 0.8,
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});
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}
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/**
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* Use [[getValue]] instead. For the previous getValue behavior, use DCMeter.
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* @deprecated
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*/
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getLevel(): Decibels {
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console.warn("'getLevel' has been changed to 'getValue'");
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return this.getValue();
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}
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/**
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* Get the current decibel value of the incoming signal
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*/
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getValue(): number {
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const values = this._analyser.getValue();
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const totalSquared = values.reduce((total, current) => total + current * current, 0);
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const rms = Math.sqrt(totalSquared / values.length);
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// the rms can only fall at the rate of the smoothing
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// but can jump up instantly
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this._rms = Math.max(rms, this._rms * this.smoothing);
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return gainToDb(this._rms);
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}
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dispose(): this {
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super.dispose();
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this._analyser.dispose();
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return this;
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}
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}
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