The display menu below offers up both overscan and edge masking choices if you have image noise along the edges to dispose of. That's something not unusual with cable or satellite signals. With overscan, you trim off the outermost data, and expand the now slightly smaller image, to fill what was the full frame. That means giving up the precision/sharpness of one to one pixel mapping.
Another alternative, which preserves 1-1 pixel masking is to use the Edge mask instead. It simply puts black up in those outmost area, eliminating the signal. You end up with a slightly smaller image but what's left is unaltered. That's my preferred solution, for the crisper image.