"Sgt. Pepper's Lonely Heart Club Band," which opens today at six area theaters, is less a testimony to the endearing and enduring quality of the original Beatles album than a graphic example of how Hollywood can convert a pleasant fantasy into to soporific sideshow.

It's doubtful that anyone old enough to attach memories ot the "Sgt. Pepper" album - or any Beatles music, for that matter - will be able to sit through two hours of the Bee Gees and Peter Frampton homogenizing the roles of the original quartet. The "Sgt. Pepper" film reduces the old cliche that imitation is the highest form of compliment into a new one: Mimicking the Beatles is the ultimate form of mockery.

If the music in this $12-million, all singing spectacle weren't enough of an audio license, the freedom that screenwriter Henry Edwards has taken with the "Sgt. Pepper" concept positively boggles the mind.

We're expected to believe that, upon the death of Sgt. Phineas Patrick Paul Pepper - an American in WWI - the musical instruments used by his military band were bequeathed to the town of the Heartland, U. S. A. As they once made enemies lie down on battlefields, they will now bring joy and happiness to his home town. Of course, the musical tradition must go on, and his grandson, Billy Shears (played by Frampton), forms a band with his three best friends (Barry, Robin and Maurice Gibb-the Bee Gees).

The boys are signed to a major record contract and fly off to Los Angeles. Meanwhile, the instruments are stolen from Heartland by Mr. Mustard, a maniacal real-estate broker with two C3PO lookalike droids who are controlled by the Future Violence Band (the rock group Aerosmith).

The main action, if it can be called that, is of the Lonely Hearts Club Band trying to get back the instruments. In the process Billy's girlfriend Strawberry Fields is killed, which allowss for the film's most awkward moment: Frampton singing Paul Mccartney's lullaby "Golden Slumbers" before the band members hike the coffin onto their shoulders.

Admittedly, the task of transforming a record album into a film is not the easiest, although producer Robert Stigwood has had a good track record of doing it. He has done "Jesus Christ Superstar" and "Tommy", initially released as recordings and then made into films.

It was probably "Tommy," the only financially successful film of director Ken Russell, that proved ot Stigwood that even the flakiest of story lines will attract a huge audience if the roles are filled with rock stars (Elton John, Eric Clapton, Tina Turner and The Who in that one).

Stigwood has reached a level of marketing expertise that allows the visual component of his films to be almost unimportant. Although his recent production of "Saturday Night Fever" was a critical and popular success, the real profit from the film has come from the sales of over $100 million in soundtrack albums of music thing, some potential viewers were primarily by the Bee Gees.

There's no doubt about the bottom line of "Sgt. Pepper." This is not a film; it's a pay-to-see advertisement for a soundtrack album that costs $15.98-the highest-priced film soundtrack album ever.

Ironically, Capitol Records has decided to use the release of the film as an opportunity to heavily promote the original "Sgt. Pepper" album by the Beatles. It will be interesting to see if a new generation of rock fans even bothers to check in on the original.

Viewers without the original "Pepper" record will also be confused by the movie's closing shot: a modest re-creation of the album's cover art. Instead of the strange melange of characters-Marilyn Monroe, Laurel and Hardy, the guard escorting Jack Ruby - the film substitutes a few score rock performers - Donoban, Wilson Pickett, Bonnie Raitt, Helen Reddy, Johny Winter - with a cardboard cutout of cowboy Tom Mix from the original album cover remaining in the blackground.

One wonders if Stigwood has dreams of a "Pepper" sequel some day, having the album cover come to life. He could probably sell a cool 10 million LPs.