There is provided a method for controlling a video output apparatus that displays on a display device three-dimensional video that a viewer facing a display surface of the display device can perceive as video protruding from the display surface to a viewer side, the method comprising steps of: acquiring a maximum protruding amount that is a value corresponding to a maximum protruding degree that the viewer perceives if the three-dimensional video is displayed on the display device; generating, using the acquired maximum protruding amount, a notification three-dimensional image for letting the viewer perceive the maximum protruding amount from the display surface; and displaying the generated notification three-dimensional image on the display device.