In a move that could tip the balance of power in the format war over the next generation of DVDs, Time Warner Inc.'s Warner Bros. Entertainment said it plans to release high-definition movies exclusively in the Blu-ray format, dealing a major blow to rival HD DVD.

The arrangement means the HD DVD format, which is backed by Toshiba Corp., will be left with support from just two major studios: General Electric Co.'s Universal Pictures and Viacom Inc.'s Paramount Pictures. Besides Warner Bros., the other major studios -- Sony Corp., Walt Disney Co. and News Corp.'s Twentieth Century Fox -- are committed to Blu-ray exclusively. The two formats are incompatible, meaning that buyers of HD DVD players cannot play movies issued in Blu-ray, and vice versa.

• Taking Sides: Warner Bros. plans to release high-definition movies only in Blu-ray format, a blow to the HD DVD format.
• Feared Obsolescence: The competing Blu-ray and HD DVD formats have made consumers wary about committing to equipment.
• A Pivotal Studio: Warner Bros. controls one of the largest film libraries in Hollywood.

Hollywood is eager to conclude the years-long battle over a format for high-definition DVDs, and Warner's decision will prompt many in Hollywood to conclude that the format war is nearly over, with Blu-ray the winner. The boom in regular DVDs, which lifted the financial performance of the movie studios in the early 2000s, has stalled, leaving the industry hungry for a new format that can entice consumers to replace their current DVD libraries with high-definition copies.

Warner Bros. executives said slowing overall DVD sales last year, and particularly last quarter, weighed heavily in their decision. Last year, DVD sales dropped 5% from 2006, according to Adams Media Research, contributing to fears among studio executives that consumers were holding off on buying DVDs of any kind until the format war was resolved.

Indeed, uncertainty over whether to bet on Blu-ray or HD DVD has been a big factor in preventing most consumers from making any decision, resulting in a stalemate. Consumers have been moving slowly, with just about one million players of either format sold. Last year, high-definition disc sales represented less than 1% of the entire DVD market, said Tom Adams of Adams Media.

Overseas, the lead in software is even more significant, with 75% of next-generation DVD sales going to Blu-ray in the United Kingdom and more than 90% in Japan, according to Kevin Tsujihara, president of Warner Bros. Home Entertainment Group.

Warner Bros. is a particularly important catch for Blu-ray, because it controls one of the largest film libraries in Hollywood. The studio's exclusive deal with Blu-ray will kick in later this year. To date, it has been issuing titles in both formats.

HD DVD has been the perpetual underdog in attempts to get consumers to upgrade their DVD players to new, high-definition players. In recent months, the battle between HD DVD and Blu-ray has seemed as muddy as ever. In August, Paramount and DreamWorks Animation surprised Hollywood by saying they would ditch Blu-ray in favor of HD DVD. The studios were enticed by millions of dollars in financial incentives -- in the form of cash and marketing support -- in exchange for exclusivity.

The competition was amped even further over the holiday season, when some big retailers offered HD DVD players for $99 that were snapped up during brief promotions.

People familiar with the situation said Warner Bros. won marketing support from Sony as part of the agreement. Toshiba also offered marketing support. However, Warner Bros. Chairman and Chief Executive Barry Meyer said the studio's decision was based on strategy foremost. "This wasn't a bidding contest," he said.

In the U.S., consumers so far have purchased more HD DVD players than Blu-ray players, but Blu-ray holds a substantial lead in sales of software. That is partly because the Blu-ray player is built into Sony's Playstation 3 game device.

The deal between Warner and the Blu-ray camp expires at a date in the future that Warner executives declined to identify. Even after it expires, "it's highly unlikely we'll switch back," says Mr. Tsujihara.

Now, the focus will turn to the remaining studios in the HD DVD camp. Provisions in the HD DVD's arrangement with Paramount could allow the studio to go back to releasing movies on Blu-ray as early as the end of the year, people familiar with the matter say. And Warner's move could put pressure on Universal Pictures to start releasing DVDs in Blu-ray in addition to, or instead of, HD DVD.

Home entertainment executives at Paramount and Universal didn't immediately return calls for comment. A Toshiba spokeswoman didn't immediately respond to an email.

"We expect HD DVD to 'die' a quick death," wrote Rich Greenfield at Pali Research in a note to clients. "While we still expect overall consumer spending on DVDs to decline at least 3% in 2008, the risk of an even worse 2008 DVD environment has most likely been avoided by Warner's early-2008 decision."

Other analysts thought HD DVD could survive Warner's decision, as long as the group could hold on to support from Universal and Paramount.

Both Blu-ray and HD DVD were scheduled to announce new titles for 2008 and give presentations at the Consumer Electronics Show in Las Vegas this coming week. But late Friday night, HD DVD cancelled its Sunday evening press conference, although it will still exhibit at the show. Blu-ray's press conference is scheduled for Monday morning.

I mean, I fully understand that it was a chance to take and I only have a few HD dvds that I will still continue to enjoy.