Judge Marilyn Patel, who also presided over the Napster case in 2001, will decide whether to keep RealDVD off the market pending the outcome of a lawsuit brought by the movie industry. Plaintiffs' lawyers claim the software can be used to make illegal copies of films and that it violates the Digital Millennium Copyright Act's prohibition on anti-circumvention technology.

The case has pitted the technology industry against the major movie studios in a fight over who gets to control how digital movies are used.

RealNetworks introduced RealDVD in September, but sales were quickly halted by the injunction granted when movie studios filed suit. The software lets users copy and play movies from their computer hard drives, much the way Apple's iTunes works with CDs. The motion picture studios worry that the software could be misused, however.

DVD copying software such as has been widely available since the Content-Scrambling System (CSS) used to copy-protect DVDs was cracked a decade ago, but RealNetworks had been trying to walk the line between enforcing copy protection and giving users a way to store movies on their computers.

In court testimony late last month, RealNetworks CEO Rob Glaser had argued that scofflaws are unlikely to use RealDVD, which costs US$30 and prevents users from burning new DVDs of their movies. There are "dozens of products" that DVD pirates could use if they wanted to make illegal copies, he told the court. "All you have to do is Google DVD ripper."