Most televisions use overscanning, resulting in some of the video being lost beyond the edges of the screen. Underscanning modifies the video timing so that the entire video signal appears in a rectangle centred on the television screen with a black border. The resolutions for square-pixel underscan and overscan images are: NTSC overscan: 640 x 480 PAL overscan: 768 x 576 NTSC underscan: 512 x 384 PAL underscan: 640 x 480.