Warner, which had decided to distribute films in the popular HD DVD format, is now the second big Hollywood company to say it will also release films in Blu-ray. However, the trend toward supporting two formats seems to be one-directional; companies dedicated to Blu-ray have not moved to add HD DVD to their mix.
The competing formats are each backed by powerful technology companies, including Sony for Blu-ray and Toshiba for HD DVD, leading analysts and executives to fear a format war similar to the one between VHS and Betamax more than two decades ago.
For several months, Hollywood studios had been split almost evenly between the two formats, each studio saying it would release high-definition DVDs next year only in one format or the other. Paramount Pictures, however, broke ranks earlier this month to say it would release films in both. Warner's decision accelerates that trend.
On Wednesday, analyst firm Forrester Research released a report that predicted the Blu-ray format would ultimately win.
On Wednesday, however, computer giant Hewlett-Packard appealed to the Blu-ray group to include some HD DVD features, including a so-called mandatory managed-copy function that previously had been a key concern of Microsoft and Intel, which support HD DVD.
"Managed copying" would allow consumers to use a home computer or server to copy a DVD, and then stream or play the DVD around a home network, but not to burn the DVD again or send its contents online. HD DVD specifications require the managed-copying feature, but Blu-ray makes it optional.
Warner said it will join the Blu-ray Disc Association's board of directors, but still plans to release movies in HD DVD format as well. Discs and players of both types are expected to reach shelves next year.