Napster fans this weekend may be unable to find thousands of songs as the company voluntarily removes titles in anticipation of a court order that could demand stronger remedies. The music file-swapping service announced the filtering plans for specific song titles at a court hearing Friday, where attorneys for the company and record labels presented arguments regarding how to police alleged copyright violations on the service. A ruling is not immediately expected. But Napster said it has created a way to screen individual file names that would likely go into effect this past weekend. Potentially millions of files will be blocked at that time, Napster attorney David Boies said. "We have had a group of people working night and day on a process to block access to these files," Boies said. "What we are doing is inserting a step between the uploading and the viewing of the index... that will block out specific file names." Included in this block will be approximately 1 million files, representing some 5,600 songs submitted to Napster by the major record labels, heavy metal band Metallica, rap artist Dr. Dre, music publishers and others. US District Judge Marilyn Hall Patel is deciding how to modify an order she first issued last July in San Francisco federal court, when she said that Napster must block all trades of works copyrighted by the major music labels. The 9th US Circuit Court of Appeals in San Francisco said last month that ruling went too far and that the record companies instead had to identify specific works to be blocked. Just what that seemingly simple mandate meant prompted wildly divergent arguments in court Friday, however, and it was unclear whether Napster's decision to begin filtering song titles would satisfy Patel. As it tries to build bridges with copyright holders, Napster also runs the risk of alienating its core membership, which may decide to seek free music elsewhere. There is no lack of would-be alternatives eager to snap up Napster's 64 million registered users. Playing ball Napster's proposal comes as the company is cooperating more closely with record labels. Still, it is the most aggressive self-policing effort by the company to date and the first tangible sign that Napster believes its chances of winning in court have faded. Patel was less openly critical of Napster in the courtroom compared with a previous injunction hearing last July, when she dismissed the company's legal arguments almost immediately after both parties had presented their cases. On Friday, she joked with Napster attorney Boies and appeared willing to take the company's interests into account in drafting her injunction. "We're here to find out what the parties can live with, something that will work for everyone," Patel said. Patel recessed without giving a specific date for her final decision, saying only that it would come soon. Napster has already asked a higher court to review last month's appeals court ruling, however. If a majority of the appellate judges agrees to hear that case, it could once again stall any ruling made by Patel over the next few days or weeks. The key question in the case now is whether Napster eventually will be forced to do more to block copyrighted works from being traded on its network. In the past, the company has said it can't differentiate between copyrighted and non-copyrighted works and would have to shut down if it were forced to separate the two. Under its current filtering proposal, the company believes it can address copyright violations, although it's unclear whether this will satisfy the court. Much of the argument Friday centred on who would bear responsibility for identifying copyrighted files on Napster's network. The record industry proposed that it submit artists' names and titles of songs and albums and that Napster then be required to find and block those songs. Napster asked that it be required to block only specific file names identified by copyright owners. "This is a case that should be settled. We are fighting to preserve the Napster community and the Napster file-sharing experience," chief executive Hank Barry said. Napster's attorneys said only songs that had actually appeared on the company's service should be included in the injunction. Record industry attorneys said that would be tantamount to allowing too much infringement to occur. "That makes no sense," said Russell Frackman, lead counsel for the record labels. "That's trying to fix it after the horse has already left the barn." At Friday's hearing, Sony, AOL Time Warner, Vivendi Universal and EMI pushed well beyond the dictates of the 9th Circuit decision in their quest to shut Napster down, insisting on an injunction that it would be impossible to comply with other than by shutting down the service. Patel must decide which of those interpretations comes closest to meeting guidelines for the injunction set out by the 9th Circuit last month, or she must craft a different standard. According to 9th Circuit's instructions, the record labels must "provide notice to Napster of copyrighted works and files containing such works available on the Napster system before Napster has a duty to disable access to the offending content. Napster, however, also bears the burden of policing the system within the limits of the system". The attorneys also sparred over issues such as how to handle proposed class-action lawsuits from independent labels and music publishers. Those issues will be discussed further at a hearing April 10. The two sides will also meet in front of a mediator 9 March. Record industry executives said they were encouraged by Napster's filtering plan but said it did not go far enough. "What Napster said today was what we've all known for years, that they can filter songs," said RIAA chief executive Hilary Rosen. Although filtering file names could put a crimp in the service, Boies said the arrangement preserved its essential features. "This does not destroy what Napster is," Boies said, adding that the system is still a peer-to-peer system between individuals and will still have more music than any other alternative. The Internet is changing the face of the music industry forever. Find out more at the MP3 Newsroom. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Napster Debate. Let the editors know what you think in the Mailroom. And read other letters.