Hollywood and RealNetworks on Tuesday filed lawsuits against each other over a dispute about whether RealNetworks' DVD-copying software violates movie studios' copyrights.

The Motion Picture Association of America filed its suit in Los Angeles federal court, accusing RealNetworks of violating the Digital Millennium Copyright Act by making it possible for people to bypass copyright protection and make copies of movies on a PC. The studio organization also asks the court to stop RealNetworks from selling its RealDVD software.

RealNetworks, on the other hand, filed a lawsuit in federal court in Northern California, asking the court to rule that the company's software fully complies with the DVD Copy Control Association's license agreement. The DVD-CCA develops the studio-sanctioned data-scrambling technology in DVDs that makes it difficult to copy the content. RealNetworks is a licensee.

The RealNetworks suit names MPAA members Disney Enterprises, Paramount Pictures, Sony Pictures Entertainment, 20th Century Fox Film, NBC Universal, and Warner Bros. Entertainment, as well as Viacom and the DVD-CCA, which contends such copying violates its license.

RealDVD, which went on sale Tuesday, makes it possible for people to copy a movie on to the PC, but adds on top of the DVD-CCA technology a layer of copyright protection that "effectively locks the DVD copy to the owner's computer to ensure that the content cannot be improperly copied or shared," the company said in a statement.

The MPAA, however, isn't buying RealNetworks' argument. In its suit, the organization said RealDVD should be called "StealDVD." The group said the purpose of the copyright protection on DVDs is to prevent any copying of the content without the permission of movie studios. "The RealDVD software illegally circumvents this copyright protection system," the group said in a statement.

Specifically, the software lets people rent DVDs from a legitimate video-rental store and build a library of copied movies without ever buying a DVD. "On its own Web site, RealNetworks acknowledges that this behavior is illegal and that its software could be used in that manner," the MPAA said.

Along with asking the court to halt the selling RealDVD, the MPAA also is asking for unspecified damages.

In filing its suit, RealNetworks is hoping the court will find its software legal in light of a 2007 California court ruling that found similar software from home entertainment technology company Kaleidescape was legal.

The Kaleidescape software made it possible to store secure copies of DVDs and CDs for more convenient playback from a PC. The DVD-CCA sued in 2004, claiming the Kaleidescape was in violation of its license. The DVD-CCA has appealed the court decision.