ShowBiz insists on maximum resolution

What program do people use to fit more than two hours of captured video onto one DVD? Even if I set my capture card to save a 3-hour TV movie as a 2 GB mpg file, my Showbiz software wants to expand the size until it’s too big to fit on a DVD. Can someone recommend a product that can render 3 hours of mpg into the proper DVD files to fit on one standard DVD? Thanks!