Camera.getCamera() doesn't detect built-in camera in MacOS 10.9

Hi,

I am using AS3 with AIR 3.1 SDK to build a live-streaming application that should be run on Windows and MacOSX. Everything works well in Windows. But when running in MacOSX (I am using Mavericks 10.9) my application can not detect built-in camera (FaceTime HD Camera). It can only capture video from USB 2.0 webcam. I've tried to quit all browsers and pretty sure that nothing is using that built-in webcam, but Camera.getCamera() still returns null.

Here is some code of mine (very ordinary and works well on Windows):

public class MyCapture {

        // Constants and Variables

        public static var _cam:Camera;          // default camera

        [Bindable] public static var strResolution:String;

        public static function set cam(c:Camera):void {

            if (!c) trace("Warning: set null camera?!");

            _cam = c;

        }

        public static function get cam():Camera {

            if (!_cam) {

                _cam = Camera.getCamera();      // get default camera on current machine

            }

            if (_cam) {

                strResolution = _cam.width + " x " + _cam.height;

            } else {

                strResolution = "";

            }

            return _cam;

        }

}

Any help will be appreciate.