THEY PROBABLY do not realize it, nor do they likely give a hoot, but a number of local TV stations in this country are running perpetual video noir festivals. Most people do not even know what video noir is, but then, the term has just this minute been invented. Yet the genre goes back to the earliest days of television, and reruns of shows like "Perry Mason" "The Untouchables" and "The Twilight Zone" help keep it alive.

Video noir programs have certain things in common. First, they are all in black and white. Second, they may defy the traditional theology of he television series that says everything will be all right after the last commercial (Perry Mason always found the real killer, but often the murder victim was someone so despicable that he clearly deserved to die, and the killer thus implicitly deserved to get away).

A video noir episode might have a downbeat or even slightly hopeless ending, it might deal with death as a subject and not just scatter miscellaneous deaths about as easy scenic decoration, and it frequently would wander midst the realms of the supernatural, the faintly perverse or the existential.

Just as there are film-noir classics like "The Big Sleep," "Murder, My Sweet," "The Blue Dahlia" and "Laura," there are video noir classics, and sometimes these are cop or detective stories like many films noir were: "The Naked City," "Peter Gunn," "Mike Hammer," "Richard Diamond," "M Squad," "The Untouchables." Often these programs even have an authentic film noir physiognomy, with low light levels (something color television virtually obliterated), heavy shadows and soundstage-city settings under artificial suns and neon moons.

THe fact is, a good print of an old "Perry Mason" can be visually beautiful - actually beautiful, in a stark, high contrast, heavy-'50s way unattainable now that all filmed shows have the same muted bluish factory tint. "Perry Mason" is a landmark in video noir from its urban-primal musical theme (by the gifted and underrated Fred Steiner) - which sets the ritualistic tone for the minimally mysterious mystery plots - to its unusually handsome monochromatic cinematography. "Perry Mason" looks like the best of the '40s B-movies and it upholds the idea of Los Angeles as the dark dream city of freezing heat that Nathanael West and F. Scott Fitzgerald immortalized.

This vision of L.A. was shattered by color TV, its accompanying inescapable use of actual exteriors (as opposed to back lot streets and studio sets) and the arrival of boyish and outdoorsy cops like the insufferable and uncharismatic "Starsky and Hutch" or the insipid vanilla teammates on "Adam 12."

Such duos can hardly compare with the imposing sight of those two incredible hulks, Raymond Burr as Mason and the late William Hopper as detective Paul Drake, when they went out together in their padded-shoulder suits to haunt a suspect or intimidate Lt. Tragg or the district attorney, both of whom, with an infallibility peculiar to tue-blue bureaucrats, were always wrong. "Perry Mason" said the system works, but generally by accident and always through the intervention of civilians and of fate.

"Perry Mason" has hardly been absent from television for an instant since the program premiered on the CBS television network in 1957. An attempt to update it, in color, with a lithe and youngish hero, was a ridiculous and doomed failure in the '70s. People watch episodes of "Perry Mason" over and over and over - reruns have been a fixture on WTTG in Washington for more than a decade - not because they are hooked by the sometimes ludicrously rudimentary plots but, partly, because they get from Perry Mason a pervasive, transporting and consistent sense of comparatively exotic video atmosphere. There is little sense of atmosphere in any current filmed TV series because now they almost all look exactly alike.

Threats of violence were a more elemental aspect of video noir than actual violence was, but explicit violence certainly existed. Perhaps on TV shows in history have matched "Naked City" and "The Untouchables" at making violence awesome and intimidating week after week. At ABC's 25th Anniversary party in Los Angeles, before he'd left for NBC, Fred Silverman watched a frantic old "Untouchables" clip in open-mouthed admiration. "I wish we could do it today - but they'd kill us."

"They" are of course the antiviolence groups who have help clean up television and, while undoubtedly improving its moral tone, have also helped prevent it from recreating the furtive, perilous, video noir milieu, even if anybody had the ambition to try. "Naked City" was not as sensationally violent as "Untouchables," and it not exist in a make-believe Chicago of the past but in an on-location New York of the present, but seeing scenes from it now makes today's crime-time shows look all the more cosmetic, escapist, and bland.

Programs of the past that attempted pro-social" messages even before the term was coined - like "The Defenders" and "East Side/West Side" - don't qualify as video noir no matter how cherished a place they occupy in television history. Their "message" intentions disqualify them, for one thing, and their attempts to deal with social issues of their day dates them now in ways that true video noir programs do not date - at least, not spiritually.

Perhaps the most timeless video noir classic of them all is also one of television's 'few true auteurist triumphs Rod Serling's "The Twilight Zone," now seen nightly in Washington on Channel 20, although, in a gesture typically half-hearted for the station, fewer than half of the 100-plus episodes available for syndication have been bought. Nevertheless, though the station keeps repeating "Twilight" shows from an inventory of only 50, the program is earning bigger ratings at 11 p.m. than did the first-run controversial series "Mary Hartman, Mary Hartman." Stations in 125 markets around the country have bought "The Twilight Zone," though it is currently airling only in 27 of them.

"Twilight Zone" was a milestone that could not be duplicated; when Serling was later recruited to host NBC's tedious and mundane "Night Gallery," there was no comparison to the original "Twilight Zone" programs he had narrated and often written. Those programs began with Serling growling out a standard enigmatic introduction in his peculiarly punchy, penetrating voice: "There is a sixth dimension beyond that which is known to man. . ."

Usually the program, an anthology of stories dealing with occult, science fiction or supernatural themes, successfully entered a seventh dimension beyond that which is known to television. Throughout the series, Serling, the only person who could be called a continuing character, and his successfully stretched their imaginations when it came to story material and narrative style.

One of the program's most celebrated installments, "The Invaders," written by frequent and invaluable contributor Richard Matheson, had essentially one character and almost no dialogue; Agnes Moorehead played an old woman trapped in a lonely house visited by a tiny but lethal flying saucer from another planet. The confrontation was eloquently skeletal, the setting for it unforgettably bleak and the O. Henry ending a corker.

When Buster Keaton starred in a story about a turn-of-the-century inventor and his herky-jerky time machine - one of the series' few comic installments - the part of the story set in the past was filmed as a silent movie with pit-piano accompaniment. When Keaton propelled himself into the noisy present of the city of '62, the film turned to sound. "Twilight" was forever, perhaps too often, dealing with tales about the defiance, purposeful or accidental, of time. In one mordant tragi-comic show, "What's in the Box?" a mercilessly nagged husband played by William Demarest is shocked to see the death of his shrewish wife, played by Joan Blondell, on television before it actually happens.

For one of its five seasons, "The Twilight Zone" was a one-hour instead of a half-hour series, and with "In His Image," written by another frequent contributor, Charles Beaumont, the program proved ahead of its time once again. George Grizzard played a man who seemed to have been stricken with selective amnesia. When also struck by a car on a road near his home town, he picked himself up to find a fresh long gash in his arm. Pulling back the torn flesh - in one of the most eye-popping moments in the history of the series - he found not veins and arteries but wires and transistors and tubes. Here was television's first bionic man - a manufactured android who'd thought he was really human.

I remember vividly the moment he pulled back that synthetic skin because it knocked me right out of my living room chair. But that was one of the great things about "The Twilight Zone"; it dared to be, on occasion, genuinely frightening, not just timidly spooky, like, say, the Boris Karloff "Thriller" series or "Night Gallery" itself. One of the all-time scariest moments in TV annals comes from a "Twilight Zone" episode called "Nightmare at 20,000 Feet," also written by Matheson.

In this one, William Shatner plays a man who boards a plane after recovering from a nervous breakdown; he is heading home. Up in the black night sky, he thinks he sees a grotesque little man hopping around on the wing of the plane and tampering with one of the engines. No one sees the man but Shatner, and he is assured the little man isn't really there. He closes the curtain over the window and tries to sleep. But he keeps wondering; is he there? Is he there? Finally, after a prelude of ingeniously sustained suspense, he opens the curtain and wham, the creature is not only there, he's staring right in, his gnarled nose pressed against the glass and all of him bigger than life.

The names in the credits of "The Twilight Zone" remain uncommonly impressive. Bernard Herrmann and Jerry Goldsmith were among the participating composers. Mitchell Leisen, Ralph Nelson, Boris Sagal, Lamont Johnson, Christian Nyby, Stuart Rosenberg, Don Siegel and Elliott Silverstein were among the directors. Robert Redford played an eerily handsome choir-boy personification of Death on one episode, and Ed Wynn played a veteran pitchman trying to make a deal with another Death spectre on another episode.

Most TV series have traditionally presented narrow views of American life, the world and the universe. Indeed, the universe has rarely been mentioned. "The Twilight Zone" may have had its gimmicky or arch chapters, but as a television program, as a work of video noir pop art, it offered an expanded vision, not a limited one, and its dramas were usually set in artificial environments barren of comforting cues or carefully established bearings. It was not the familiar but the unfamiliar that the program celebrated, and it brought routine television to a new level of beguiling adventure for the engageable mind.