Not so much a documentary as a poignant video essay (and so much the better), "Drive-In Blues," on Channel 26 at 8:30 tonight, lovingly evokes the age of the outdoor movie theater, one of those eras that has passed, but not without leaving a treasury of memories for sentimental slobs everywhere.

Patrons of today's omniplexes, octaplexes and solarplexes probably can't appreciate the lure of what Variety dubbed the "ozoners," where one watched the movie from one's car, abetted by a bevy of tasty treats hauled in from the snack bar, a building that usually looked like a cinder block bomb shelter.

The opening image in "Blues" is a heartbreaking sign of the times, a drive-in screen being dismantled in strips and then pulled with a clumpf to the ground.

Perhaps drive-ins will come back, since they were born in the (last) Depression. The first one opened in 1933 in Camden, N.J. In-car speakers hadn't been invented, so giant boomers were placed aside the screen. Patrons had to leave their windows rolled down to hear. Mosquito repellent was hawked in the snack bar.

Known in later years as "passion pits" because of the teen-age hanky-panky that went on willy-nilly (hence Pauline Kael's book title "I Lost It at the Movies"), drive-ins were first pitched as family fun centers. Bring the kids, save on baby sitters, pay less than at a regular theater, and be together.

Promotional gimmicks, extolled in short films included in "Drive-In Blues," made it all sound so wholesome, whatever the season: "Horrific Spook Frolic and Free Wiener Roast for Halloween." In the Southwest, drive-ins tended to stay open year-round.

Another promo film invites patrons to haul along their enfeebled friends, as well as elderly people and invalids "and others whose physical proportions make it uncomfortable or impossible for them to sit in an ordinary theater seat." How delicately put! In the early days, car trunks were sometimes searched for smuggled-in moviegoers; now, in the few drive-ins left, they are searched for drugs and weapons.

"Drive-In Blues" might have taken notice of the many movies that had scenes at or near drive-ins, like "Midnight Cowboy" and "Sugarland Express" and, most recently, that bizarre Australian HBO discovery, "Dead-End Drive-In," which fantasizes an ozoner that serves as a punk purgatory. But this would perhaps be mere marginalia.

Jan Krawitz, who produced and directed the half-hour film, made it a rollicking eulogy. There's no attempt to be all-encompassing, just to give a valid and vivid impression. The promotional shorts are a big help. One warns patrons that pay television is a "monster" waiting to invade their living rooms. In a way, they were right about that.

'Legacy of the Blacklist' As the Legion of Decency used to say of some motion pictures, "Legacy of the Hollywood Blacklist," a PBS documentary about the Red Scare of the '40s and '50s, is morally objectionable in part for all. The film, at 10 on Channel 26, is not as much about a "legacy" -- the aftermath of the blacklisting era -- as it is another maudlin wallow in the cruelty of the times themselves.

They were cruel times, but most times are. Lines were drawn more sharply than usual, and more arbitrarily, and members of the House Un-American Activities Committee (HUAC), including chairman J. Parnell Thomas, did behave abominably, and about as un-Americanly as is possible.

Yet the liberals and lefties and aspiring intellectuals of Hollywood weren't a chorus of blameless saints, as the film suggests. The documentary melodramatizes the oppressiveness of the persecutors without really considering the wider political context that encouraged hysterical postwar and Cold War fears.

Producer-director Judy Chaikin does a poor job of organizing and editing the material -- the report keeps beginning, over and over -- and insists on heavy-handed where evenhanded would have been preferable. Some of the survivors of blacklisted writers use buzz phrases like "progressive movement" and "internationally oriented" that, for what it's worth, still sound like communist cant to this day.

If the program had been strictly a series of oral recollections, without the nudging Burt Lancaster narration and the clumsily interpolated newsreel footage, it might have had more credibility. Some of those participating do have moving, troubling stories to tell -- among them actress Evelyn Keyes, recalling her horror when writer John Howard Lawson was drowned out in his impassioned testimony by the lunatic, gavel-pounding Thomas, who might as well have been beating the First Amendment as his desk.

Jane Wyatt, the all-American mom on "Father Knows Best," recalls how movie offers in the '40s dwindled almost overnight when she was placed on the list of "Red Channels." Betty Garrett, widow of Larry Parks ("The Jolson Story"), is still pained by memories of how her husband was ostracized by the Hollywood community because he had appeared to cooperate with the committee.

Dalton Trumbo's children remember answering phone calls for "Mr. Jackson" and numerous other Trumbo pseudonyms once he was blacklisted and could not use his own name. These are good stories, but they are almost lost in Chaikin's polemic assault.

She has some curious notions about art and commerce in Tinseltown, too. The groundless contention is made that if the Hollywood Ten had been able to keep working, American movies of the '50s would have been far more meaningful and humane. Titles like "Pillow Talk," "Beach Blanket Bingo," "Girls! Girls! Girls!" and "Gidget Goes Hawaiian" are blamed on the McCarthy era. All were released well after the era had ended and after a disgraced and abandoned McCarthy had died.

"Legacy of the Hollywood Blacklist" rehashes material covered in such superior films as Emile de Antonio's "Point of Order." The only new twist it adds is incompetence.