MediaTrackSettings.autoGainControl - Web APIs 编辑

The 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 MediaTrackConstraints.autoGainControl property you provided when calling either getUserMedia() or 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 MediaTrackSupportedConstraints.autoGainControl as returned by a call to MediaDevices.getSupportedConstraints(). However, typically this is unnecessary since browsers will ignore any constraints they're unfamiliar with.

Syntax

var autoGainControl = MediaTrackSettings.autoGainControl;

Value

A Boolean value which is true if the track has automatic gain control enabled or false if AGC is disabled.

Example

See Example: Constraint exerciser in Capabilities, constraints, and settings for an example.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Media Capture and Streams API
• Capabilities, constraints, and settings
• MediaTrackConstraints.autoGainControl
• MediaTrackSupportedConstraints