Wattstax, a one-day summer concert held at the Los Angeles Memorial Coliseum on Aug. 20, 1972, was named for the Stax recording artists -- including the Staple Singers, Rufus Thomas and Isaac Hayes -- who performed in a seven-hour concert to mark the Watts riots of 1965.

Despite its success at the time -- upward of 100,000 people were said to have attended -- this event might have disappeared into the information-age quicksand had it not been for "Wattstax," a remarkably penetrating documentary made by executive producer David L. Wolper, director Mel Stuart and Columbia Pictures, who financed the film for $500,000.

Thanks to the efforts of restoration expert-detective Tom Christopher and many others, the movie, now titled "Wattstax -- The Special Edition," has been restored and rereleased and its soundtrack remastered. There's something new, too: the famously lost ending. When the 1973 "Wattstax" was released, MGM threatened to sue Columbia for the closing two Hayes numbers "Shaft" and "Soulsville," which were prominently featured in MGM's "Shaft." Consequently, a new ending was shot, and the Hayes section was shelved. Thankfully, the Hayes finale is part of the new film.

In 1972, Stuart thought there should be more to the film than concert footage. He wanted a sense of cultural perspective. So he sent crews (many of them African American) into Watts to interview local residents about politics, culture and their lives. Stuart also heard about a rising new comedian named Richard Pryor, and thought his provocative, witty insights might add heft to the film. His instincts were right. Pryor, who sat down for a lengthy interview for the film, delivered big time. In fact, his repartee, which punctuates the musical footage, is the political conscience of the movie, a sort of verbal lightning. His jokey material ranging from the depiction of blacks trying to get work out of prison to commentary on police shootings, turns this movie into something deeper.

The result is a time capsule par excellence, one that starts with a young, afro-haloed Jesse Jackson leading the crowd in his signature anthem "I Am Somebody," and concludes with Hayes's charismatic renditions of "Shaft" and "Soulsville." In between is a living, breathing record of black America coming into its own in a self-confident, aware and angry way. It is a full 20 years before the L.A.. riots, the ones that followed the acquittal of police officers in the beating of Rodney King, and yet you can feel a sense of anticipation. This is the overture to that show of fury. But there's more than unresolved bile. There is also Black Is Beautiful pride. You can see it in the glorious costumes on stage and off, the theatricality of soul handshakes, the unrestrained display of dancing in the auditorium and the music itself -- a piquant combination of soul, gospel and pop.

This is the best of times and the worst of times, African American style.

WATTSTAX (R, 104 minutes) -- Contains obscenity and brief nudity. At the Cineplex Odeon Wisconsin Avenue and AMC Academy Greenbelt.

Mavis Staple performs with the Staple Singers at the Wattstax concert in Los Angeles in 1972.