files/en-us/web/api/mediatracksettings/autogaincontrol/index.md
{{APIRef("Media Capture and Streams")}}
The {{domxref("MediaTrackSettings")}} dictionary's
autoGainControl property is a Boolean value whose value
indicates whether or not automatic gain control (AGC) is enabled on an audio track. This
lets you determine what value was selected to comply with your specified constraints for
this property's value as described in the
{{domxref("MediaTrackConstraints.autoGainControl")}} property you provided when calling
either {{domxref("MediaDevices.getUserMedia", "getUserMedia()")}} or
{{domxref("MediaStreamTrack.applyConstraints()")}}.
Automatic gain control is a feature in which a sound source automatically manages changes in the volume of its source media to maintain a steady overall volume level. This feature is typically used on microphones, although it can be provided by other input sources as well.
If needed, you can determine whether or not this constraint is supported by checking the value of {{domxref("MediaTrackSupportedConstraints.autoGainControl")}} as returned by a call to {{domxref("MediaDevices.getSupportedConstraints()")}}. However, typically this is unnecessary since browsers will ignore any constraints they're unfamiliar with.
A Boolean value which is true if the track has automatic gain control
enabled or false if AGC is disabled.
See the Constraint exerciser example.
{{Specifications}}
{{Compat}}