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 instantly applied, causing unaesthetic 'clicks' in the resulting audio. To prevent this from happening, never change the value directly but use the exponential interpolation methods on the AudioParam
interface.
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" |
Constructor
GainNode()
- Creates a new instance of a
GainNode
object. You shouldn't manually create a gain node; instead, use the methodAudioContext.createGain()
.
Properties
Inherits properties from its parent, AudioNode
.
GainNode.gain
Read only- Is an a-rate
AudioParam
representing the amount of gain to apply. You have to setAudioParam.value
or use the methods ofAudioParam
to change the effect of gain.
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> <button class="mute">Mute button</button> </div>
var audioCtx = new (window.AudioContext || window.webkitAudioContext)(); var gainNode = audioCtx.createGain(); var mute = document.querySelector('.mute'); var source; if (navigator.mediaDevices.getUserMedia) { navigator.mediaDevices.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 == "") { // 0 means mute. If you still hear something, make sure you haven't // connected your source into the output in addition to using the GainNode. gainNode.gain.setValueAtTime(0, audioCtx.currentTime); mute.id = "activated"; mute.innerHTML = "Unmute"; } else { gainNode.gain.setValueAtTime(1, audioCtx.currentTime); mute.id = ""; mute.innerHTML = "Mute"; } }
Specifications
Specification | Status | Comment |
---|---|---|
Web Audio API The definition of 'GainNode' in that specification. |
Working Draft |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
GainNode | Chrome Full support 14 | Edge Full support ≤18 | Firefox Full support 25 | IE No support No | Opera Full support 15 | Safari Full support 6 | WebView Android Full support Yes | Chrome Android Full support 18 | Firefox Android Full support 26 | Opera Android Full support 14 | Safari iOS Full support Yes | Samsung Internet Android Full support 1.0 |
GainNode() constructor | Chrome
Full support
55
| Edge Full support ≤79 | Firefox Full support 53 | IE No support No | Opera Full support 42 | Safari ? | WebView Android
Full support
55
| Chrome Android
Full support
55
| Firefox Android Full support 53 | Opera Android Full support 42 | Safari iOS ? | Samsung Internet Android
Full support
6.0
|
gain | Chrome Full support 14 | Edge Full support 12 | Firefox Full support 25 | IE No support No | Opera Full support 15 | Safari Full support 6 | WebView Android Full support Yes | Chrome Android Full support 18 | Firefox Android Full support 26 | Opera Android Full support 14 | Safari iOS Full support Yes | Samsung Internet Android Full support 1.0 |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- See implementation notes.
- See implementation notes.