audio-stream-meter

Simple meter for showing audio stream volume.

Installation

1$ npm install audio-stream-meter

Quick start

1var AudioStreamMeter = require('audio-stream-meter');
2
3navigator.mediaDevices.getUserMedia({audio:true})
4.then(stream => {
5	var audioContext = new AudioContext();
6				
7    var mediaStream = audioContext.createMediaStreamSource(stream);
8    var volume = document.getElementById('volume');
9
10    var meter = AudioStreamMeter.audioStreamProcessor(audioContext, function() {
11        volume.style.width = meter.volume * 100 + '%';
12    });
13      
14    mediaStream.connect(meter);
15    stream.onended = meter.close.bind(meter);
16});
17
18<!-- html volume -->
19<div style="width:300px;height:30px;background-color:#FF00FF">
20	<div id="volume" style="height:30px;background-color:#00FFFF"></div>
21</div>

Configuration

1var config = {
2	bufferSize: 1024, // default: 1024, interval: {0, 256, 512, 1024, 2048, 4096, 8192, 16384} 
3	inputChannels: 1, // default: 1, interval: [1, 32]
4	volumeFall: 0.95, // default: 0.95, interval: (0,1)
5	throttle: 1, // default: 1, interval: [1, 10]
6};
7
8var meter = AudioStreamMeter.audioStreamProcessor(audioContext, callbackFn(), config);

• bufferSize - more value create higher latency of audio sample-frames,
• inputChannels - how many input channels should be handling, passing more channels then exists in stream will flatten volume,
• volumeFall - more means volume wave will be fall slower.
• throttle - sets step for which will be take samples for calculations, see percent of calculated samples by means of formula f(x) = 1 / x * 100,

Controls

• callbackFn() - function is invoke after each processing audio samples and can use within data from 'Output data' paragraph. For example: callbackFn(){ console.log(meter.volume)}
• meter.close() - close and disconnect audio processing

Output data

• meter.volume - gives info about volume of the last package of samples - intervals [0, 1],

Licence

MIT