Sales of movies on Blu-ray high-definition discs exceeded sales of films on the rival HD-DVD format by a 2-to-1 margin in the United States in the first half of 2007, Home Media Research said on Tuesday.

The division of Home Media Magazine said total sales of Blu-ray discs, which use a Sony Corp.-backed technology, totaled 1.6 million units from January 1 through July 1 while 795,000 HD-DVD discs were sold in that period.

HD-DVD was developed by Toshiba Corp. and is backed by Microsoft Corp. and film studios such as Warner Bros.

Both high-definition formats were launched in spring of 2006. An estimated 3.7 million of both types of discs have been sold overall, including 2.2 million Blu-ray discs and 1.5 million HD-DVD discs, through the end of July, according to Home Media.

A Home Media spokeswoman said Blu-ray got a boost in August from strong sales of the movie 300. Stephen Nickerson, senior vice president, market management, at Warner Home Video, reported sales of about 190,000 Blu-ray units of the film, versus 97,000 in HD-DVD since July 31.

The industrywide standards war is reminiscent of the VHS vs. Betamax battle.

Blockbuster Inc., the largest U.S. retailer of home movie entertainment, in June set out plans to line its shelves with Blu-ray DVDs, saying Blu-ray rentals were "significantly outpacing" HD-DVD rentals.

From COMPUTERWORLD