mirror of
https://github.com/Tonejs/Tone.js
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103 lines
2.5 KiB
JavaScript
103 lines
2.5 KiB
JavaScript
define(["Tone/core/Tone", "Tone/component/Analyser", "Tone/core/AudioNode"], function(Tone){
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"use strict";
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/**
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* @class Tone.Meter gets the [RMS](https://en.wikipedia.org/wiki/Root_mean_square)
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* of an input signal with some averaging applied. It can also get the raw
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* value of the input signal.
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*
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* @constructor
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* @extends {Tone.AudioNode}
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* @param {Number} smoothing The amount of smoothing applied between frames.
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* @example
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* var meter = new Tone.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.getValue();
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*/
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Tone.Meter = function(){
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var options = Tone.defaults(arguments, ["smoothing"], Tone.Meter);
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Tone.AudioNode.call(this);
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/**
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* The analyser node which computes the levels.
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* @private
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* @type {Tone.Analyser}
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*/
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this.input = this.output = this._analyser = new Tone.Analyser("waveform", 1024);
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/**
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* The amount of carryover between the current and last frame.
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* Only applied meter for "level" type.
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* @type {Number}
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*/
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this.smoothing = options.smoothing;
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};
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Tone.extend(Tone.Meter, Tone.AudioNode);
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/**
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* The defaults
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* @type {Object}
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* @static
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* @const
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*/
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Tone.Meter.defaults = {
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"smoothing" : 0.8
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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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* @returns {Decibels}
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*/
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Tone.Meter.prototype.getLevel = function(){
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this._analyser.type = "fft";
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var values = this._analyser.getValue();
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var offset = 28; // normalizes most signal levels
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// TODO: compute loudness from FFT
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return Math.max.apply(this, values) + offset;
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};
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/**
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* Get the signal value of the incoming signal
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* @returns {Number}
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*/
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Tone.Meter.prototype.getValue = function(){
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this._analyser.type = "waveform";
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var value = this._analyser.getValue();
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return value[0];
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};
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/**
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* A value from 0 -> 1 where 0 represents no time averaging with the last analysis frame.
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* @memberOf Tone.Meter#
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* @type {Number}
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* @name smoothing
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* @readOnly
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*/
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Object.defineProperty(Tone.Meter.prototype, "smoothing", {
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get : function(){
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return this._analyser.smoothing;
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},
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set : function(val){
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this._analyser.smoothing = val;
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},
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});
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/**
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* Clean up.
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* @returns {Tone.Meter} this
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*/
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Tone.Meter.prototype.dispose = function(){
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Tone.AudioNode.prototype.dispose.call(this);
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this._analyser.dispose();
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this._analyser = null;
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return this;
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};
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return Tone.Meter;
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});
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