Lawyers for Napster revealed a licensing deal with an online music service owned in part by three major record labels that they say unfairly limits the ability of consumers to download music on Napster’s Web site.

Lawyers for the record companies immediately dismissed the agreement as irrelevant to their attempt to gain damages for copyright infringement against Napster. But U.S. District Judge Marilyn Hall Patel seemed taken aback by the news and indicated it could bog down the long-running litigation.