most dvds are 7gb and its hard to fit 7gb on a 4.7gb blank. there is a few legal freewares you can use. try DVDshrink and/or DVDfab (in the free section at the bottom of there page). these are used to make backups of your movies.
There are TONS of programs designed to rip dvds down to single layer. Just use one of those. You may have to give up the extras but most all dvd movies will fit on a single layer