The Carnival Liberty cruise ship does have DVD players in their cabins. Passengers will find a number of amenities and perks aboard the ship, including interactive TV sets that allow you to order pay-per-view movies, DVD players, VCRs, wireless Internet service, a separate seating area, and a stocked mini-bar. There are also public areas of the ship where passengers can watch television, movies, use on-board computers equipped with wireless Internet, and more. Luxury suites on the ship even have televisions and DVD/VCR players in their spacious bathrooms.
For more info, see Carnival Liberty Cruise Ship