It’s as inevitable as it is unfair to compare Keaton to the silent screen’s largely undisputed giant, Charles Chaplin. But while Chaplin’s little tramp got by with poignancy and charm, Keaton’s stone-faced alienation seems ever more in tune with the American sensibility. More important, Keaton was the superior filmmaker. His 1926 runaway-train adventure, ”The General,” is widely considered one of the greatest films of any era, and, as Orson Welles points out in an introduction included here on a disc of extras, Keaton’s trenchant Civil War images rival those of pioneering photographer Mathew B. Brady. Even in minor classics like ”Our Hospitality,” ”College,” and ”The Navigator,” Keaton was every bit the auteur-before-his-time, expert in his use of sight gags, matte paintings, heart-racing crowd scenes (the chase from ”Seven Chances” features a mob of wedding-gowned women pursuing his hot-to-trot bachelor), even dabbling in underwater filming. Sadly, by ’33 his best work was well behind him, and while his downfall is often blamed on the advent of talkies (his gravelly dry voice was no friend to the microphone), it was more likely his subjugation to the efficiencies of the studio system, and a serious drinking problem, that spelled his demise. For that reason, watching late?’30s talkies like ”Jailbait,” let alone his TV appearances from the ’50s and ’60s, is a bit of a downer, as is the absence from Art of a documentary profile of Keaton. But with 11 features and 19 shorts to choose from, who’s complaining?