mirror of
https://github.com/Tonejs/Tone.js
synced 2024-11-16 16:48:00 +00:00
100 lines
2.3 KiB
JavaScript
100 lines
2.3 KiB
JavaScript
define(["../core/Tone", "../component/Analyser", "../core/AudioNode"], function(Tone){
|
|
|
|
"use strict";
|
|
|
|
/**
|
|
* @class Tone.Meter gets the [RMS](https://en.wikipedia.org/wiki/Root_mean_square)
|
|
* of an input signal. It can also get the raw
|
|
* value of the input signal.
|
|
*
|
|
* @constructor
|
|
* @param {Number} smoothing The amount of smoothing applied between frames.
|
|
* @extends {Tone.AudioNode}
|
|
* @example
|
|
* var meter = new Tone.Meter();
|
|
* var mic = new Tone.UserMedia().open();
|
|
* //connect mic to the meter
|
|
* mic.connect(meter);
|
|
* //the current level of the mic input in decibels
|
|
* var level = meter.getLevel();
|
|
*/
|
|
Tone.Meter = function(){
|
|
|
|
var options = Tone.defaults(arguments, ["smoothing"], Tone.Meter);
|
|
Tone.AudioNode.call(this);
|
|
|
|
/**
|
|
* A value from 0 -> 1 where 0 represents no time averaging with the last analysis frame.
|
|
* @type {Number}
|
|
*/
|
|
this.smoothing = options.smoothing;
|
|
|
|
/**
|
|
* The previous frame's value
|
|
* @type {Number}
|
|
* @private
|
|
*/
|
|
this._rms = 0;
|
|
|
|
/**
|
|
* The analyser node which computes the levels.
|
|
* @private
|
|
* @type {Tone.Analyser}
|
|
*/
|
|
this.input = this.output = this._analyser = new Tone.Analyser("waveform", 1024);
|
|
};
|
|
|
|
Tone.extend(Tone.Meter, Tone.AudioNode);
|
|
|
|
/**
|
|
* The defaults
|
|
* @type {Object}
|
|
* @static
|
|
* @const
|
|
*/
|
|
Tone.Meter.defaults = {
|
|
"smoothing" : 0.8,
|
|
};
|
|
|
|
/**
|
|
* Get the current decibel value of the incoming signal
|
|
* @returns {Decibels}
|
|
*/
|
|
Tone.Meter.prototype.getLevel = function(){
|
|
var values = this._analyser.getValue();
|
|
var totalSquared = 0;
|
|
for (var i = 0; i < values.length; i++){
|
|
var value = values[i];
|
|
totalSquared += value * value;
|
|
}
|
|
var rms = Math.sqrt(totalSquared / values.length);
|
|
|
|
//the rms can only fall at the rate of the smoothing
|
|
//but can jump up instantly
|
|
this._rms = Math.max(rms, this._rms * this.smoothing);
|
|
|
|
return Tone.gainToDb(this._rms);
|
|
};
|
|
|
|
/**
|
|
* Get the signal value of the incoming signal
|
|
* @returns {Number}
|
|
*/
|
|
Tone.Meter.prototype.getValue = function(){
|
|
var value = this._analyser.getValue();
|
|
return value[0];
|
|
};
|
|
|
|
/**
|
|
* Clean up.
|
|
* @returns {Tone.Meter} this
|
|
*/
|
|
Tone.Meter.prototype.dispose = function(){
|
|
Tone.AudioNode.prototype.dispose.call(this);
|
|
this._analyser.dispose();
|
|
this._analyser = null;
|
|
return this;
|
|
};
|
|
|
|
return Tone.Meter;
|
|
});
|