This is a collage film by the New York painter Alfred Leslie. He made three films including The Last Clean Shirt (with poet Frank O'Hara, avail) and Pull My Daisy (with Jack Kerouac). The captures here are a valid rendering of the original film, because like Thom Anderson's Los Angeles Plays Itself, many of these clips are probably from pretty raunchy sources (VHS, TV, etc), and as such related to Leslie's somewhat materialist aesthetic. And after all the film is about the bar where the Abstract Expressionists hung out.
The eponymous bar of the title was where all poets, painters and critics in New York in the 1950s around the abstract expressionist circle drank and had aesthetic and fist fights, people like Barnett Newman, Willem De Kooning and Helen Frankenthaler, Jackson Pollack and art critic Clement Greenberg. Leslie was there and he wrote a play about what he heard, which forms the backbone of this film. Clips of a reading of that play are intercut with all sorts of Hollywood and television imagery, and also some very hard core porn. The play is a searing critique about painting and the people who write about it. Sometimes it might even be incoherent, but it's usually entertaining, if you can follow the many layers of visual puns, in-jokes and knee-slappers (and bathroom humor). The film itself is falling apart at the seams, losing pieces as it drives down the road.