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NEW YORK/LOS ANGELES, Jan 4 (Reuters) - Time Warner Inc's TWX.N Warner Bros studio on Friday said it would exclusively release high-definition DVDs in Sony Corp's 6758.T Blu-ray format, dealing a big blow to Toshiba Corp's 6502.T rival HD DVD technology.

Warner Bros, Hollywood’s biggest seller of DVDs, representing about 18 to 20 percent of sales in the United States, was one of the few studios that backed both formats.

All sides of the format war had agreed it was confusing to consumers and a stumbling block for a potential multibillion-dollar industry.

Total DVD unit sales fell 4.5 percent in 2007, the first major year-over-year decline since the disc format debuted in 1997, according to Adams Media Research. Sales fell 4.8 percent to $15.7 billion.

“The window of opportunity for high-definition DVD could be missed if format confusion continues to linger. We believe that exclusively distributing in Blu-ray will further the potential for mass market success and ultimately benefit retailers, producers, and most importantly, consumers,” Warner Bros Chairman and Chief Executive Barry Meyer said in a statement.

News Corp's NWSa.N 20th Century Fox, Walt Disney Co DIS.N, and Lionsgate LGF.N are among studios backing the Blu-ray format. Viacom Inc's VIAb.N Paramount studios and General Electric's GE.N NBC Universal release movies in HD DVD format.

Warner said it would continue releasing in the HD DVD format until the end of May, although those releases would follow the standard DVD and Blu-ray releases. (Reporting by Kenneth Li in New York and Bob Tourtellotte and Peter Henderson in Los Angeles; Editing by Brian Moss)