The createGain()
method of the AudioContext
interface creates a GainNode
, which can be used to control the overall volume of the audio graph.
var gainNode = AudioContext.createGain();
A GainNode
.
The following example shows basic usage of an AudioContext
to create a GainNode
, which is then used to mute and unmute the audio when a Mute button is clicked by changing the gain
property value.
The below snippet wouldn't work as is — for a complete working example, check out our Voice-change-O-matic demo (view source.)
<div> <a class="mute">Mute button</a> </div>
var audioCtx = new (window.AudioContext || window.webkitAudioContext)(); var gainNode = audioCtx.createGain(); var mute = document.querySelector('.mute'); var source; if (navigator.getUserMedia) { navigator.getUserMedia ( // constraints - only audio needed for this app { audio: true }, // Success callback function(stream) { source = audioCtx.createMediaStreamSource(stream); }, // Error callback function(err) { console.log('The following gUM error occured: ' + err); } ); } else { console.log('getUserMedia not supported on your browser!'); } source.connect(gainNode); gainNode.connect(audioCtx.destination); ... mute.onclick = voiceMute; function voiceMute() { if(mute.id == "") { gainNode.gain.value = 0; mute.id = "activated"; mute.innerHTML = "Unmute"; } else { gainNode.gain.value = 1; mute.id = ""; mute.innerHTML = "Mute"; } }
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'createGain()' in that specification. | Working Draft |
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|---|
Basic support | 10.0webkit | (Yes) | 25.0 (25.0) | No support | 15.0webkit 22 (unprefixed) | 6.0webkit |
Feature | Android | Edge | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|---|
Basic support | ? | (Yes) | 26.0 | 1.2 | ? | ? | ? | 33.0 |
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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/AudioContext/createGain