MediaTrackSettings: aspectRatio property

The MediaTrackSettings dictionary's aspectRatio property is a double-precision floating-point number indicating the aspect ratio of the MediaStreamTrack as currently configured. This lets you determine what value was selected to comply with your specified constraints for this property's value as described in the MediaTrackConstraints.aspectRatio property you provided when calling either getUserMedia() or MediaStreamTrack.applyConstraints().

If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.aspectRatio as returned by a call to MediaDevices.getSupportedConstraints(). However, typically this is unnecessary since browsers will ignore any constraints they're unfamiliar with.