RealNetworks and the Motion Picture Association of America (MPAA) have filed dueling lawsuits against each other over a product that allows people to copy DVDs.

The MPAA, in a lawsuit filed Tuesday, accused RealNetworks of allowing its customers to illegally copy DVDs through its RealDVD software, released in early September. RealNetworks filed its own lawsuit Tuesday, responding to threats of a lawsuit by MPAA members.

The RealNetworks lawsuit, filed in U.S. District Court for the Northern District of California, targets seven movie studios and the DVD Copy Control Association, a group that licenses the Content Scramble System (CSS) encryption technology built into DVDs that prevents unauthorized reproduction.

RealDVD "fully complies" with the DVD Copy Control license agreement, RealNetworks said in a press release. RealDVD is intended to allow customers to store and play their DVDs on their computers, but it does not allow users to distribute copies because it locks the DVD copy to one computer, RealNetworks said.

The RealNetworks lawsuit asks the district court to rule that RealDVD legally complies with the CSS license.

Kaleidescape, the makers of a similar product, prevailed in a March 2007 ruling on a lawsuit brought by the DVD Copy Control Association, RealNetworks noted.

"Having lost the case once, the major studios are now trying to get a different result by going to a different court," RealNetworks said in a statement. "We are disappointed that the movie industry is following in the footsteps of the music industry and trying to shut down advances in technology rather than embracing changes that provide consumers with more value and flexibility for their purchases."

The MPAA, in its lawsuit, said RealDVD violates the U.S. Digital Millennium Copyright Act (DMCA) by illegally bypassing the copyright protection built into DVDs.

RealDVD would allow a customer to rent a DVD, rip it onto a computer and return it without buying a copy, the MPAA said.

"RealNetworks' RealDVD should be called StealDVD," Greg Goeckner, the MPAA's executive vice president and general counsel, said in a statement. "We will vigorously defend our right to stop companies from bringing products to market that mislead consumers and clearly violate the law."

The movie industry in recent years has focused on investing in new technologies that allow customers to access movies in new and legal ways, including online video on demand, he said.

The MPAA's lawsuit, filed in U.S. District Court for the Central District of California in Los Angeles, asks for an injunction against the sale of RealDVD. RealNetworks is improperly making a product based on the CSS license that allows users to circumvent CSS protections, the MPAA said.