The video source is facing away from the user, such as the back camera on a mobile device facing the user's environment.
The video source is facing toward the user but to their left, such as a camera aimed toward the user but over their left shoulder.
The video source is facing toward the user but to their right, such as a camera aimed toward the user but over their right shoulder.
The video source is facing toward the user, such as a front-facing camera on a mobile device.
facingModefor mobile browser, see https://developer.mozilla.org/en-US/docs/Web/API/MediaTrackConstraints/facingMode.