The idea of renovating ''Yellow Submarine'' occurred to Bruce Markoe, the vice president of feature postproduction at MGM/UA, in 1995, when he played the film for his 5-year-old daughter. She loved it, Mr. Markoe said; but as a more critical viewer, he was disappointed that the colors were not as dazzling as he remembered them and that the soundtrack was flat by modern standards.

''I thought, 'We have something valuable here, something that a couple of generations haven't seen,' '' he said. ''I also thought that this was a film that cried out for upgrading with today's technology. So I went to John Calley, who was the president of the company at the time, and pitched him the idea of renovating the film for rerelease.''

Mr. Markoe was told he could proceed once the legal problems were settled. That took a year. It took nearly as long for Mr. Markoe to get Apple to agree to allow the Beatles' music to be remixed for Surround Sound from the master tapes. In recent years, as the 60's recordings by the Byrds, the Who, the Kinks and other bands have been remixed and remastered to take new technologies into account, the Beatles have generally insisted that their music be left alone. In his meetings with Neil Aspinall, the chief executive at Apple, Mr. Markoe argued that simply replacing the mono recordings on the soundtrack with the stereo versions available on CD was not the best option.

''I told Neil that audiences are used to 5.1 digital sound in the movies now,'' Mr. Markoe said, ''and that while we could spread out the stereo mixes for 5.1, it would compromise the recordings. I think that was the key, because the Beatles never liked to settle for compromises. Neil said we could go ahead, with the understanding that if the Beatles didn't approve the new mixes, we couldn't use them.''

The audio remixing got under way in October 1997 with Peter Cobbin, a staff engineer at EMI's Abbey Road Studios in London, at the remixing desk. Mr. Cobbin's task was inherently contradictory: the songs had to sound much as they originally did, yet the new mixes had to take advantage of the six-channel capability.

''A very detailed kind of attention was needed to make sure that everything was put back the same,'' Mr. Cobbin said of his mixes. ''As you're probably aware, there are many takes of a song, and even within the take that was used for the record, there may be guitar solos or vocal harmonies that were not used. So a lot of time was spent seeing that the right elements were used.''