By Maggie Shiels
Technology reporter, BBC News, Silicon Valley
The movie studios have described RealDVD as "StealDVD"
Hollywood has locked horns with the technology industry over who will control digital entertainment and how it is watched.
The six big film studios say a program called RealDVD violates copyright.
This week a San Francisco court could decide if DVD users can make personal backups the way people do with audio.
"The consumer should have the same fair use rights to copy DVDs just as they have for the last decade with music," said Bill Hankes of RealDVD.
RealDVD, which is made by RealNetworks, allows DVD owners to make digital copies of their discs onto a computer or laptop hard drive for their own personal use without having to pay extra.
Downloadable versions of many movies are available online, and some studios let users make a digital copy of a movie onto a computer by paying more for an "expanded edition" of a DVD.
Many believe this means the consumer is being made to pay twice.
Kevin Hunt who writes the Electronic Jungle column for the Baltimore Sun said: "For 11 years, since the Digital Millennium Copyright Act (DMCA) made it illegal to bypass any digital rights management protection system, the movie and music industries have fought a war ostensibly against piracy.
"In reality, it has been a war against the consumer, designed to make people pay more than once for the same song or album or movie."
At the heart of the case the movie studios, represented by the Motion Picture Association of America (MPAA), claim that RealDVD is illegal under the DMCA.
Figures show the DVD market in the US was worth almost $22bn in 2008
The Association said the software bypasses the copy protection built into DVDs meaning that users could copy a DVD and share it around. The studios have described the product as "Steal DVD."
The real fear being expressed is that the technology would enable people to "rent, rip, and return" DVDs.
These are the terms used to describe someone who rents a DVD, copies the content onto a hard drive and returns the movie without ever paying for the unauthorised copy.
"Our objective is to get the illegal choices out of the marketplace and instead focus constructively with the technology community on bringing in more innovative and flexible legal options for consumers to enjoy movies," Greg Goeckner, executive vice president and general counsel, MPAA told the BBC in an e-mail statement.
RealNetworks, which makes RealDVD, claimed that in actual fact the company has enhanced the security of the product.
"We have added an extra layer of security encryption, the same the government uses, to ensure piracy is not a possibility," said RealDVD spokesman Mr Hankes.
A digital version made using RealDVD can only be played on the computer that made the copy.
The DVD Copy Control Association, which is primarily responsible for the copy protection of DVDs and also suing RealNetworks, told the BBC it would not comment until the case is resolved.
RealDVDs' Mr Hankes said he had not been surprised by Hollywood's reaction to the product.
"There has been a tension between Silicon Valley and Hollywood for a long time and this is another example of that.
The MPAA said the cost of movie piracy is the industry's biggest threat
"It is not uncommon for content owners to be initially concerned about the manner in which their content will be treated by new technology. That is why we went to talk to the studios before we released the product," said Mr Hankes.
The National Consumers League, a 100-year-old consumer watchdog group, said a survey it conducted in conjunction with RealNetworks showed consumers want choice.
"The entertainment industry would be wise to pay attention to the attitudes and purchase desire of the typical American consumer, who, according to our survey, is very interested in being able to back up his or her collection," said executive director Sally Greenberg.
To some extent the genie is already out of the bottle because there are a number of illegal ways to do what ReadDVD does.
"Consumer behaviour is going to continue regardless of what happens in this court case. The question is can Hollywood and technology get out in front of it so the consumer adopts legitimate behaviour," said Mr Hankes.
Fred Von Lohmann, a senior lawyer with the Electronic Frontier Foundation suggested the picture is not so black and white.
"Hollywood says that without encryption, the DVD market would collapse. I say, the pirates have already won, the software to copy is free and you're still selling DVDs."
"The sky has not fallen," added Mr Von Lohmann.
The case in the U.S. District Court for the Northern District of California is being heard by Judge Marilyn Patel. She presided over the Napster case and eventually shut down the original peer-to-peer music file-sharing service.
The hearing, which will resume on Thursday, is expected to end this week with closing arguments this Friday or the following week. Most people expect Judge Patel to deliver her decision in a written ruling in the coming weeks.