In the latest test of copyright laws in the digital age, a company that sells software to create copies of DVDs went to court yesterday to prevent being sued by the movie industry.

In a lawsuit filed in U.S. District Court in San Francisco, 321 Studios of St. Louis wants a judge to declare that its product, DVD Copy Plus, does not violate copyright laws.

"It's a critical issue in this digital age," said 321 President Robert Moore, who started the company in July as a hobby. "Someone's got to stand up and say it's wrong when you can't make a copy of something you own."

Moore said the lawsuit is a preemptive strike against an indirect threat of a copyright infringement suit from the Motion Picture Association of America, the trade group that represents studios named in the suit.

MPAA spokeswoman Emily Kutner said the group had no immediate comment because the studios had not had time to review the complaint. The suit names nine studios, including MGM, TriStar, Columbia, Time Warner, Disney, Universal and Pixar.

The program, based on controversial open-source code that descrambles DVD encryption, is designed to let users make a backup copy of a DVD movie. The suit argues that copyright laws allow such copying for personal use.

Moore, a veteran software developer, has sold 75,000 copies of DVD Copy Plus over the Internet. The firm has 32 employees and has opened offices in three cities, including Berkeley, with hopes of expanding into retail stores.

The current DVD Copy Plus version only copies parts of a DVD, at reduced quality, onto a CD, but future versions will be designed for recordable DVDs, Moore said.

The suit claims that a newspaper story published on March 11, quoting Ken Jacobsen, the MPAA's antipiracy director, hinted that the motion picture industry was going to take 321 Studios to court.

"We believe that there are substantial constitutional problems with the Digital Millennium Copyright Act, not the least of which is barring consumers from exercising their right to make backup copies of DVDs they own," said 321 Studio attorney Daralyn J. Durie of Keker & Van Nest of San Francisco.