The GainNode
interface represents a change in volume. It is an AudioNode
audio-processing module that causes a given gain to be applied to the input data before its propagation to the output. A GainNode
always has exactly one input and one output, both with the same number of channels.
The gain is a unitless value, changing with time, that is multiplied to each corresponding sample of all input channels. If modified, the new gain is applied using a de-zippering algorithm in order to prevent unaesthetic 'clicks' from appearing in the resulting audio.
Number of inputs | 1 |
---|---|
Number of outputs | 1 |
Channel count mode | "max" |
Channel count | 2 (not used in the default count mode) |
Channel interpretation | "speakers" |
Properties
Inherits properties from its parent, AudioNode
.
GainNode.gain
Read only- Is an a-rate
AudioParam
representing the amount of gain to apply.
Methods
No specific method; inherits methods from its parent, AudioNode
.
Example
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"; } }
Specifications
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'GainNode' in that specification. |
Working Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 10.0webkit | 25.0 (25.0) | No support | 15.0webkit 22 |
6.0webkit |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | ? | 26.0 | 1.2 | ? | ? | ? | 33.0 |