Hi there. Basicially a DVD rip is usually an exact copy of the original DVD where as a DVD scr (screener) would usually contain a letterbox , but without the extras that a DVD retail would contain. The ticker is not usually in the black bars, and will disrupt the viewing. If the ripper has any skill, a DVDscr should be very good. Usually transferred to SVCD or DivX/XviD.
This site would explain others as well as this in more detail:
www.vcdquality.com/index.php?page=faq


