The case of the hidden movie, or 'Haven't I seen that scene before?'

Do you ever have the feeling you're watching two movies at once?

There's the movie that was advertised, of course, with its chills or chuckles for the ordinary filmgoer. And sometimes there's a ''hidden'' movie, too: a series of in-group references aimed at savvy, ''cineliterate'' members of the audience.

It's a growing trend. Now that the movies have almost a century of history behind them, filmmakers are eager to exploit their heritage. This goes especially for the bright film-school graduates.

They may do it with on-screen ''quotes'' like the ones in ''E.T. The Extra-Terrestrial'' and ''Poltergeist.'' These include snippets from old pictures - ''The Quiet Man'' and ''A Guy Named Joe'' - on TV sets in the background.

Or the references may be more ingrained, like the '40s-style ''film noir'' lighting in ''Body Heat,'' the Saturday-matinee structure of ''Raiders of the Lost Ark,'' the old-fashioned characters of ''An Officer and a Gentleman.''

At best, this practice adds fun for the few without confusing or distracting the casual moviegoer. At worst, it leads to self-conscious pastiches like ''Blow-Out,'' with its heavy borrowings from Hitchcock and Antonioni, and half-baked remakes like ''The Thing'' and ''Cat People.''

Writing in the arts journal October, critic Noel Carroll calls this ''the game of allusion,'' and identifies it as a major current in contemporary filmmaking. Often the ''in'' references are added for the sake of amusement alone. At other times, Carroll points out, the filmmaker uses ''allusionism'' as a means of telegraphing information about the plot and attitudes toward the characters.

Carroll's article misses the important point that movies are simply imitating literature in this respect - developing the kind of cultural reflexivity that T.S. Eliot and Ezra Pound insisted upon decades ago as a key resource for poetry and criticism. But the essay is right on target in pinpointing the ''allusion game'' as a hot item in Hollywood circles. And it usefully calls the bluff of pretentious directors who believe a clever reference is a substitute for original thought.

The latest director to play the allusion game is Robert Benton, whose last outing was the well-received ''Kramer vs. Kramer.'' His new movie, Still of the Night, is another elegantly shot, superbly edited drama starring Meryl Streep. She plays a glamorous but enigmatic New Yorker whose boyfriend has been mysteriously murdered. Is she the killer? Will she knock off our hero, a sleuthing psychiatrist played by Roy Scheider? Or is the plot thicker than it seems?

Benton builds the yarn carefully, drawing us into a web of suspense with a string of deftly timed surprises. But after a while, you get the feeling you've seen this all before.

And you have, in a long list of Alfred Hitchcock classics. There's a telephoto shot right out of ''Rear Window,'' a 'Spellbound'' dream sequence, a ''Psycho'' murder, and a climax that recalls ''To Catch a Thief'' and ''Saboteur'' among others.

Following in the master's footsteps is one thing, but purloining his boots is quite another. Not since Brian De Palma's mish-mash ''Dressed To Kill'' has a movie drawn so drastically from Hitchcock's once-unique vocabulary.

Many scenes are effective, even impressive, despite their second-hand look; and it's refreshing to see Benton also borrowing an old-fashioned sense of restraint when it comes to the sex-and-violence angles, keeping them well within PG boundaries. Still, you can't help wondering when Benton will run out of things to borrow and take off under his own steam.

Sadly, he never does. The resolution of ''Still of the Night'' is flat and stale, a limp letdown after the provocative buildup the filmmaker (and his invisible collaborator) have provided.

Benton is a sophisticated player of the allusion game. He wants to entertain all his viewers, not just nudge film buffs in the ribs. He recognizes the importance of style and technique in constructing a thriller. And he knows enough to borrow from the very best, picking up extra benefits from the Hitchcockian atmosphere - suspense by association, you might call it - that pervades his movie.

But borrowings can only take him, and us, so far. When the time comes for atmosphere to pay off in real surprise, Benton doesn't make the grade. For all its virtues, ''Still of the Night'' is a disappointment. Film in sculpture New York

Leandro Katz is among the many artists who use film not for its own sake alone, but as an element of sculptural work.

''The Judas Window,'' on view through Sunday at the Whitney Museum of American Art, is a fine example of this growing trend. It consists of several related pieces, including a movie. Entering the exhibition space, one sees a huge parasol made of pages from books, including ''Robinson Crusoe.'' Moving deeper into the room, one finds a slide projection of an ancient carving, a footprint etched in earth, a mysterious black enclosure that's meant to resemble Thomas Edison's film studio, and a case of seashells arranged in correspondence with letters of the alphabet. Behind them all is the black-draped cinema screen, bearing images of the moon on a cloud-drenched night, interspersed with abrupt and unexpected slogans.

In each of these pieces, Katz means to play with relationships among language , objects, and ideas; and the show as a whole is aimed at catching elusive connections among these distinct yet related categories. An exercise in semiology (the science of signs and symbols), it's also an imposing display on the most immediate visual level.

The museum's New American Filmmakers Series will continue Dec. 10-19 with a videotape show called ''Ideology/Praxis,'' including works by Judith Barry and the team of Isaac Cronin and Terrel Seltzer. ''Passes,'' a video installation by veteran cineaste Ed Emshwiller, will open Dec. 23 for a three-week run. The Oscar game

With nominations for the 1983 Academy Awards coming up later this winter, two major films are taking unusual steps to make sure they're in the running.

''Frances,'' a biography of former movie star Frances Farmer, isn't due for release until late January, when it will open around the United States. To qualify for the next Oscar race, though, a film must play commercially in Los Angeles before Dec. 31. So the new drama from Universal Pictures will begin a special week-long engagement tomorrow at one Los Angeles theater, also playing at a New York movie house for good measure.

This tactic, which has been used successfully in the past, doesn't guarantee any Oscar nominations. But it puts ''Frances'' - starring Jessica Lange, Sam Shepard, and Kim Stanley under Graeme Clifford's direction - in the starting gate along with the regular 1982 contenders.

And what about first-class movies that opened almost a full year ago? No longer fresh in memory, might they be overlooked by Oscar voters when balloting time finally arrives?

That's the predicament of ''Missing,'' the Costa-Gavras drama starring Jack Lemmon and Sissy Spacek. There's little doubt that ''Missing'' is the best American picture of 1982, by any standard, and it ought to cop a slew of Oscars if given half a chance. To make sure it's prominent in the minds of academy members, Universal is bringing ''Missing'' back to the screen, with a nationwide reissue due next month.

Again, the tactic doesn't assure an inside track toward the elusive Oscar. But it should help the visibility of a worthy item that might otherwise be eclipsed by the flood of newer movies due between now and year's end.