Major players in the entertainment and technology industries plan to announce a measure of detente today in what are increasingly contentious battles over the best way to prevent digital piracy of music and video.

The big music-recording companies are joining two trade groups representing large computer hardware and software makers in opposing legislation that would require hardware and software to be designed to defeat piracy.

None of the three groups -- the Recording Industry Association of America, the Business Software Alliance and the Computer Systems Policy Project -- would comment on the specifics of the joint principles that are to be released at a news conference.

But sources familiar with the agreement said it is designed to try to ease the tension between the technology industry, which opposes any government mandates on how technology should be designed, and the entertainment industry, which has been seeking federal help in combating what it sees as a growing problem of consumers illegally copying and swapping digital music and video.

The technology groups count as members companies such as Microsoft Corp., Intel Corp., Dell Computer Corp. and International Business Machines Corp. They support protecting intellectual property but have disagreed with the entertainment industry on how it should be done.

Generally, it has been the movie industry that has been the prime mover behind legislation requiring the use of anti-piracy devices. And the most prominent bill, sponsored by Sen. Ernest F. Hollings (D-S.C.), is widely viewed as having little chance of passage because of tech-industry resistance.

But people familiar with the new deal speculate that by coming out against such legislation, the music industry is trying to repair its battered reputation in places such as college campuses as being a bunch of conglomerates that want to prevent consumers from freely listening to, recording and trading music. The music trade group has been especially active in the courts, where it has succeeded in persuading judges to close down music file-sharing services such as Napster.

The result has been that the entertainment industry has gained a reputation as being anti-technology.

"They may want to distance themselves" from the movie industry in the public's mind, said one person familiar with the industry. "They've been getting whacked."

A technology industry insider said that without saying so directly, the agreement also means that technology companies will oppose efforts to relax existing copyright laws or to clarify user's digital rights.

Consumer groups, the consumer electronics industry and even some large technology corporations such as Intel have argued that the 1998 Digital Millennium Copyright Act is overly restrictive and should be changed. Under the law, for example, it is technically illegal for users to record downloaded music and replay it in their cars.

Rep. Rick Boucher (D-Va.) said that legislation he is sponsoring to ease the act's restrictions will not be affected by the new agreement.

"It sounds like the agreement is characterized by who is not part of it," said Boucher, noting that neither the Consumer Electronics Association -- which supports his bill -- nor the Motion Picture Association of America, which opposes it, are parties to the deal.

The agreement says that the government should not be involved in helping to set "consumer's expectations" about what constitutes fair use of digital content, sources said. Spokesmen for both the electronics and motion picture associations said they could not comment until they saw the details of the agreement.

Many technology companies, such as Microsoft, already oppose tinkering with the copyright act and support its vigorous enforcement.

But others, such as Intel, Sun Microsystems Inc. and Gateway Inc., have supported Boucher's bill, and Boucher said he has no indication that will change.

Others on Capitol Hill applauded the deal, even if it has limited effect.

"I have long noted that copyright and technology creators have a symbiotic relationship, and have lamented the growing rift between the two communities," said Rep. Howard L. Berman (D-Calif.), who is sponsoring legislation favored by the record labels that would allow companies to engage in a measure of hacking on their own to disrupt the efforts of digital pirates.

That legislation is reviled by consumer and privacy groups, which argue that it could open the door to widespread invasion of privacy. Those groups also charge that the agreement is another example of big businesses getting together to decide what is best for consumers.

"If they can find a way to divide up the rents, then I'll be the one paying for it," said Mark N. Cooper, research director of the Consumer Federation of America.