audio-stream-meter

Simple meter for showing audio stream volume.

Installation

$ npm install audio-stream-meter

Quick start

var AudioStreamMeter = require('audio-stream-meter');

navigator.mediaDevices.getUserMedia({audio:true})
.then(stream => {
    var audioContext = new AudioContext();
				
    var mediaStream = audioContext.createMediaStreamSource(stream);
    var volume = document.getElementById('volume');

    var meter = AudioStreamMeter.audioStreamProcessor(audioContext, function() {
        volume.style.width = meter.volume * 100 + '%';
    });
      
    mediaStream.connect(meter);
    stream.onended = meter.close.bind(meter);
});

<!-- html volume -->
<div style="width:300px;height:30px;background-color:#FF00FF">
	<div id="volume" style="height:30px;background-color:#00FFFF"></div>
</div>

Configuration

var config = {
	bufferSize: 1024, // default: 1024, interval: {0, 256, 512, 1024, 2048, 4096, 8192, 16384} 
	inputChannels: 1, // default: 1, interval: [1, 32]
	volumeFall: 0.95, // default: 0.95, interval: (0,1)
	throttle: 1, // default: 1, interval: [1, 10]
};

var 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) = 100 / x

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