Warner Bros., the only major movie studio to release titles on both of the rival high-definition video disc formats, has decided to drop HD DVD and exclusively back Blu-ray Disc, it said Friday.

The move could prove decisive in determining which of the two formats becomes the de facto DVD replacement for high-definition content. Currently, both formats are battling to secure a lead but neither has managed to obtain a meaningful market share due to consumer indifference as a consequence of the battle. As a result, the market for high-definition movies has seen its growth stunted and companies like Warner have lost potential sales.

Warner said the decision was made in part as a response to this situation.

"A two-format landscape has led to consumer confusion and indifference toward high definition, which has kept the technology from reaching mass adoption and becoming the important revenue stream that it can be for the industry," said Kevin Tsujihara, president of Warner's home entertainment group in a statement.

Last year Paramount Pictures, which also released movies on both formats, jumped the opposite direction and adopted HD DVD in preference to Blu-ray Disc. With Warner's announcement only two major Hollywood studios are backing HD DVD: Paramount and Universal. The others have all put their weight behind Blu-ray Disc.

The move comes on the eve of the Consumer Electronics Show, which kicks off on Monday in Las Vegas, and is sure to light a fire under the HD DVD camp, which is chiefly backed by Toshiba and also includes Microsoft and Intel. In reaction to Warner's announced the group cancelled its CES news conference that was due to take place on Sunday evening. The rival Blu-ray Disc group is scheduled to speak the following day.

Companies from both sides of the format battle are expected to show their latest players and talk-up their own formats during CES.

Last year's CES saw the unveiling by Warner of a hybrid disc called Total HD. The disc attempted to break the format deadlock by offering one side compatible with HD DVD and the other side compatible with Blu-ray Disc. However, the disc never made it to market and Warner gave up on the hybrid format later in 2007.