Movies are an American pastime, a release into a world dominated by images triggering both conscious and subconscious responses. One of the rewarding paradoxes of viewing a film in a dark theater is the ability to feel identification with an audience while simultaneously experiencing deeply personal emotions. A lot like the feelings you get at a good rock concert. So why not amalgamate the two events? Voila! the age of the rock'n'roll movie musical is now upon us.

There have been some rock movies before, but they were usually filmed concerts like "Woodstock," "Monterey Pop" and "Gimme Shelter" (the Rolling Stones' concert at Altamont). Such docu-rockers are still around. The Band's "THE LAST WALTZ" is not only a three-record set but a movie directed by Martin Scorsese ("Mean Streets," "Alice Doesn't Live Here Anymore," "Taxi Driver," "New York New York"). No one is quite sure what Bob Dylan's "Reynaldo and Clara" is, but it does show a lot of Rolling Thunder Revue footage. But what we have here are theatrical films rooted heavily in rock'n'roll music, which results in rock'n'roll soundtrack albums. Which means you might need a guide to see what records are playing now at a theater near you.

"FM": The film claims to be the story of life on the mellow side of the dial, but what FM rock station in the country could go an hour and 45 minutes without playing one song by Wings? Despite that omission, the "FM" soundtrack is a solid collection of mostly well-known cuts. The real prizes are Steely Dan's ingratiating title track, which sounds more "Royal Scam"-ish than anything on "Aja"; Jimmy Buffett's blistering "Livingston Saturday Night"; and tunes by ex-Eagle Randy Meisner, present-day Eagle Joe Walsh, Eagle fan club president Linda Ronstadt (newly recorded live versions of "Tumbling Dice" and "Poor Poor Pitiful Me") and the Eagles themselves ("Life in the Fast Lane"). There's also James Taylor, Bob Seger, Boston, Dan Fogelberg, Boz Scaggs, Foreigner, Queen, Steve Miller, the Doobie Brothers, Billy Joel and a hard-driving "Breakdown" by the relatively unknown Tom Petty and the Heartbreakers. "FM" turns out to be an excellent display of progressive radio's recent greatest hits.

"AMERICAN HOT WAX": You might call this the flip side of "FM." Here's the rock'n'roll at its beginning and, though the film itself is distorted into insignificance, the music is vibrant and important. Like "FM," "American Hot Wax" is a two-record package; but this one has a stero live half and a mono studio half. The live record features ageless wonders Chuck Berry and Jerry Lee Lewis doing their classics: Berry duckwalks through "Reelin' and Rockin'" and "Roll Over Beethoven," and the Killer rips up "Whole Lotta Shakin' Goin' On" and nearly stomps "Great Balls of Fire" to death. Also featured are Clark Otis, the Delights (who include songstress Brenda Russell) and Professor La Plano and the Planotones - actually the highly acclaimed new band, Brooklyn Dreams. For those who go way back, the studio ablum has tunes by such legends as Jackie Wilson, the Drifters, Buddy Holly and Little Richard. There's also the not-so-legendary work of the Cadillacs, the Elegants, the Turbans and the Spaniels. Whether you go way back or not, this musci will show you what the "good old days" actually sounded like. Besides, who could pass up an album that both Frankie Ford's "Sea Cruise" and Bobby Darin singing "Splish Splash"?

"THANK GOD IT'S FRIDAY": Like the beer commercial says, if you haven't heard of this one yet, you will. The film, built around a disco, gives Donna Summer a great excuse to undulate through 15 minutes and 51 seconds of "Je T'Aime." Besides Summer, whose album sales combined with those of Kiss have made Casablanca Records solvent enough to bankroll such projects, "T.G.I.F." boasts the Commodores, Diana Ross and Thelma Houston. One object here is rhythm, and all the tracks are timed in "beats per minute" (Houston's "Love Masterpiece" is the champ, clocking in at 148). Another object is success, and Casablanca president and "T.G.I.F." executive producer Neil Bogart is sparing no promotion. This mutli-record set is bound to heat up the discos. The package even includes a mail-order coupon to send for your very own "T.G.I.F." T-shirt ($5) and warmup jacket ($12).

"GREASE": And speaking of production numbers, Robert Stigwood is hoping that "Grease," scheduled to open here in June, will be the next "Saturday Night Fever." It's a pretty sure bet that the "Grease" album won't sell like the "Saturday Night Fever" album, but there's some reason for optimism. For one, "You're the One That I Want" is already a hit single. Cleverly produced by John Farrar, the song is mixed so that John Travolta's half of the duet (with Olivia Newton-John) practically disappears. Travolta may be bucking to be the new Gene Kelly, but he certainly isn't the new Frank Sinatra. He's not even the current Frank Sinatra. "Grease" keeps Travolta's singing just inside the bearable limit and gets some surprisingly strong moments from Newton-John, Stockard Channing (last seen here in "The Big Bus"), Sha-Na-Na (obviously feeling right at home) and Frankie Valli. Valli's version of the title cut, produced by Barry "Bee Gee" Gibb, may be the best track on the two records. Finally, there's even an appearance by the real Frankie Avalon.

If you don't like this lineup, you can wait until July, when Stigwood presents "SGT. PEPPER'S LONELY HEARTS CLUB BAND." The movie. And accompanying soundtrack.