The film industry is pitted against hacker groups and the Linux development community this week in a civil case that will test the legality of a utility that allows DVDs to be copied and transmitted over the internet.

The case concerns Decode Content Scrambling System (DeCSS), a utility written last year as part of a project to develop a DVD driver for Linux. A Windows version is now available.

DeCSS has been called the MP3 of movies, but it will be a long time before bandwidths allow massive DVD files to be swapped as easily as audio files over the web.

Nevertheless, Hollywood is still sufficiently alarmed by the prospect of a flood of digital video piracy to take the editor of a hacker site to court to prevent the distribution of the utility.

Eric Corley, editor-in-chief of 2600.com, a hacker magazine and website, faces a lawsuit which alleges violation of an untested 1998 federal law that aims to protect digital media, the Digital Millennium Copyright Act.

The plaintiffs in the case, which include Hollywood's eight biggest studios, are seeking an injunction to prevent Corley from including hyperlinks on his site that point to the DeCSS utility.

Corley, who now goes by the name Emmanuel Goldstein after a character in the George Orwell novel 1984, provoked the anger of the film industry by posting source code for DeCSS on his website. He has since taken this down but refuses to delete hyperlinks to other sites where the utility may be obtained.

"This case is about freedom of speech. It's about the right of a computer user to play with technology in any way they like - without then facing charges," Corley told reporters at a press conference in New York. He added that 2000 sites have posted links to the controversial DeCSS program.

The Motion Picture Association of America (MPAA), the trade group for the Hollywood studios, argues that free speech is not at issue since the only purpose of DeCSS software is to get around copyright protection.

Jack Valenti, president and chief executive of the MPAA, said: "This is a case of theft. The posting of the de-encryption formula is no different from making and then distributing unauthorised keys to a department store. The keys have no real purpose except to circumvent the locks that stand between the thief and the goods he or she targets."

Appearing for the plaintiffs, Carnegie Mellon professor Michael Shamos sought to demonstrate that that downloadable copies of popular films such as The Matrix are readily available online. He said that his assistant went into an Internet Relay Chat channel and received an illicit copy of The Matrix in exchange for a copy of Sleepless in Seattle. However, he admitted that the transfers took approximately six hours.

"The same thing is going to happen to videos as happened with Napster," Shamos told the court. The trial, before US District Judge Lewis Kaplan in a Manhattan federal court, continues today. Up to 30 Linux activists are staging a demonstration outside the courtroom.