Microsoft stepped up efforts to avoid the next-generation DVD format wars and turn its Xbox gaming console into a mainstream platform for downloadable, high-definition entertainment -- announcing a slew of partnerships that will put new HD content on its Xbox Live online service.

Under deals disclosed Sunday at the Consumer Electronics Show in Las Vegas, Microsoft will add to its Xbox Live download store HD movies and programs from ABC, Disney, and MGM Studios.

The offerings include hit ABC shows such as Lost, Grey's Anatomy, and Ugly Betty.

Available Disney programming will include Hannah Montana and The Suite Life of Zack & Cody. Meanwhile, movie lovers will able to download to their Xboxes HD versions of MGM classics like Rocky, Dances With Wolves, and Rain Man.

"Partnering with Microsoft allows us to make our legendary library available to millions of Xbox Live members," said Jim Packer, co-president of worldwide television at MGM, in a statement.

Microsoft said that its Xbox Live service, which lets Xbox users tap games and movies over the Internet, now counts more than 10 million subscribers.

The deals are part of Microsoft's campaign to make Internet-connected televisions -- powered, of course, by Microsoft software and services -- the primary source for HD content.

If the company is successful, it could make moot the current format war between high-definition DVDs encoded in the Blu-ray and HD DVD formats. Microsoft is hedging its bets, however, as it currently sells an Xbox add-on that plays HD DVD discs.

Internet rumors were rife that Microsoft chairman Bill Gates would use his CES keynote Sunday to introduce a version of the Xbox 360 with a built-in HD DVD player, as Microsoft rival Sony includes a built-in Blu-ray player in its PlayStation console.

Such an announcement never materialized.

The HD DVD camp received a major setback last week after Warner Bros. said it would no longer support the format and would henceforth release high-definition DVDs exclusively on Blu-ray. The move left Universal and Paramount as the only remaining studios supporting HD DVD.

If Gates was planning to unveil an HD DVD version of the Xbox 360, Warner's decision -- timed to coincide with the opening of CES -- may have scotched the plan. London's Financial Times reported that vendors at CES have canceled numerous HD DVD-related events and announcements on the heels of Warner Bros.' move.