Why cover over the bottom of slow motion football replays with Script, etc.

One possible item is that your TV screen Display size is a little larger than the TV's Window.  Use the TV specific remote control and look for Wide Angle or a toggle that changes the actual screen size.  Maybe you are viewing a low resolution channel with HD TV or the opposite.  Cox has started to broadcast even the lowered numbered channels in HD, as high as 1920 but if TV is not HD capable like an analog, you could get a compromised display.  I get this happening on PC Viewing alot.