New to DVD

125 mins., unrated, $29.99) One of the great benefits of DVD is that it allows you not only to experience movies with superior audio and video, but -- with the help of supplementary materials often included -- to gain a new understanding of them. But goodies on this celebratory wide-screen edition of the Julia Roberts-Richard Gere romantic comedy don't so much enhance the Pretty Woman experience as extend it: I guess the thinking was that if you love the film, you'll love having even more stuff about the film, even if it's an uninspired making-of featurette, a smidgen of behind-the-scenes footage (mostly of Roberts and Gere just standing around, waiting), and a music video of Natalie Cole's ''Wild Women Do.'' Director Garry Marshall's rambling commentary offers a few surprises, including the fact that every hotel in Los Angeles declined to be featured in the film (except for the Regent Beverly Wilshire), claiming that there were no prostitutes in their hotels, but it's not enough to enliven this perfunctory disc. C