MediaTrackSupportedConstraints: autoGainControl property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

TheMediaTrackSupportedConstraints dictionary'sautoGainControl property is a read-only Boolean value which is present (and set totrue) in the object returned byMediaDevices.getSupportedConstraints() if and only if theuser agent supports theautoGainControl constraint.If the constraint isn't supported, it's not included in the list, so this value will never befalse.

You can access the supported constraints dictionary by callingnavigator.mediaDevices.getSupportedConstraints().

TheautoGainControl constraint indicates whether or not the browser offers the ability to automatically control the gain (volume) on media tracks; this obviously is contingent on whether or not the individual device supports automatic gain control as well; it's typically a feature provided by microphones.

Value

This property is present in the dictionary (and its value is alwaystrue) if the user agent supports theautoGainControl constraint.If the property isn't present, this property is missing from the supported constraints dictionary, and you'll getundefined if you try to look at its value.

Examples

This example displays whether or not your browser supports theautoGainControl constraint.

<div></div>

#result {  font:    14px "Arial",    sans-serif;}

const result = document.getElementById("result");const supported =  navigator.mediaDevices.getSupportedConstraints().autoGainControl;result.textContent = supported ? "Supported!" : "Not supported!";