Viacom, Walt Disney, Microsoft and other media companies have agreed to a set of guidelines to protect copyrights online but Google was notably absent from the pact. The companies agreed to use technology to eliminate copyright-infringing content uploaded by Web users and to block any pirated material before it is publicly accessible.

"These principles offer a road map for unlocking the enormous potential of online video and user-generated content," Disney Chief Executive Bob Iger said in a statement issued by the participating companies.

Interest in online video has boomed over the last two years, putting media content owners at odds with Web sites that host videos when their users upload copyrighted material without permission.

Google and its YouTube video-sharing site, for example, face a $1 billion copyright infringement suit filed by Viacom.

The industry group also included Fox and MySpace units, CBS , NBC Universal, and online video services such as Veoh Networks and Dailymotion.

Although Google was not part of the group announced at an Internet conference in San Francisco on Thursday, analysts said it will likely have to adhere to the guidelines if they become standard industry procedure.

Among the provisions in the pact is an agreement to implement "commercially reasonable" content identification technology by the end of this year, which some including the MySpace social networking site have already done.

In what may be a preemptive move, Google this week unveiled new technology that allows content owners to automate the identification of copyrighted material on its YouTube online video service. The technology does not yet allow the blocking of copyrighted content from being uploaded.

Speaking at the Web 2.0 conference, Dauman, who said Viacom would likely work with Google some day, welcomed Google's recent actions but said he sought a more common standard.