When "Wattstax" makes its national television debut on the PBS series "P.O.V." Wednesday, it will have come full circle after a journey to obscurity and back. When the film, a documentary about a 1972 concert in Los Angeles commemorating the Watts riots seven years earlier, made its theatrical debut 30 years ago, it disappeared almost immediately, the victim of disputes over music rights and a lackluster marketing campaign on the part of its distributor, Columbia Pictures.

But over the years, "Wattstax," which features performances by legendary Stax Records artists including Rufus Thomas, the Emotions, the Bar-Kays, the Staple Singers, Albert King and Isaac Hayes, has become something of an underground classic, passed from hand to hand on videos copied over and over again from one-off television broadcasts and midnight movie screenings. In 2000 it began showing up at film festivals, garnering interest in a film that documents not only the seven-hour concert at Los Angeles's Memorial Coliseum, but also contains some remarkable interviews with members of the Watts community reflecting on black life, as well as a running commentary by an emerging comedian named Richard Pryor.

While "Wattstax" was winning over a new generation of on the festival circuit, those fans were seeing a bastardized version of the film. In 1973, just after its premiere at Dorothy Chandler Pavilion in Los Angeles, "Wattstax" director Mel Stuart received a call from MGM ordering him to cut Hayes's performance of "Theme From Shaft" and "Soulsville" from the film. The studio, which released "Shaft," owned the rights to both songs.

Stuart immediately cut the scenes and filmed Hayes on a soundstage singing "Rolling Down a Mountainside," footage he edited so expertly that it looked as if Hayes had actually performed the song at the concert. The original ending was considered lost until a few years ago, when film editor Tom Christopher, while working on a restoration of "Amadeus," located the 16mm negative of Stuart's original film in a Los Angeles storage facility. By this time, MGM's rights to the song had expired, and the meticulous job of reinstating the missing footage began. Last year, "Wattstax" was re-released in theaters on its 30th anniversary with a restored soundtrack and picture, as well as its rightful ending of Hayes singing "Theme From Shaft" and "Soulsville."

But it's this week's broadcast of "Wattstax" that's the real triumph for Stuart, now 76. "If you come out with a big picture and it makes $200 million, so 20 million people have seen it," he said recently by phone from his home in Los Angeles. "What's that in a country of 290 million people? It's nothing. Only by playing over and over again on TV do you reach the big audience." (A special edition of "Wattstax," as well as the soundtrack, will be released this week on DVD and CD, respectively.)

Stuart, whose films include the 1971 classic "Willy Wonka and the Chocolate Factory," 1969's "If This Is Tuesday, It Must Be Belgium," and 1981's "The White Lions," notes that both times the documentary was released in theaters, Columbia only gave it a "halfhearted release," failing to exploit the large audience of white fans of classic soul and rhythm and blues.

"It is well known in the black community," Stuart says of "Wattstax." "What I'm hoping is that by being on PBS, we'll be able to move over and show this picture to a huge white audience that has never seen it."

Indeed, music fans have long cherished "Wattstax" for its memorable performances, including Rufus Thomas singing "Do the Funky Chicken," the Emotions performing an electrifying version of the gospel hymn "Peace, Be Still" in a tiny Watts church, Johnnie Taylor delivering a blazing rendition of "Jody's Got Your Girl and Gone" in a nightclub and the Staple Singers burning through their classic "Respect Yourself."

In addition to a classic concert film, "Wattstax" is a colorful, often hilarious time capsule of 1970s style, from huge Afros and hot pants to dashikis and outsize fedoras. It's also, by design, a candid glimpse of a black community facing poverty, racism, and its own internal squabbles with a mixture of anger, resignation and hope.

When Stuart agreed to make "Wattstax," he and producers Forest Hamilton and Larry Shaw agreed that the film should not just be a "black Woodstock," but a larger portrait of African American life at that particular juncture, when the legacy of the civil rights movement was still fragile and uncertain. Stuart decided to send crews of young black filmmakers into Watts to conduct intimate conversations with men and women on the street, asking them about everything from heartbreak to the lasting effects of prejudice.

"I'm not black," Stuart says, "and I knew that only through the black perspective could this picture become important and successful. I could make the movies, but I couldn't make this movie unless I had their help, to make me understand their view of the world."

In addition to those conversations, Stuart wanted someone to serve in a "chorus of 'Henry V' " role, someone who could weave together the interviews and music into a cohesive whole. Hamilton and Shaw told him about a comedian they had seen performing at a small Watts nightclub.

When Stuart visited the club, "I walked over and saw this little skinny guy on the stage and within 10 minutes I knew he was a comic genius." The next day, Stuart interviewed 32-year-old Richard Pryor for two hours as the comedian riffed on anything and everything that came to his mind. "I would go, 'women,' " Stuart recalls of the improvisatory process, "or I would go, 'politics.' I'd just use one word. 'The blues.' And he'd just go on a roll for 15 minutes." The resulting material shows Pryor at the height of his quicksilver wit, at once hilariously funny and bordering on uncontrollable rage.

The welter of feelings that propels the performances and interviews of "Wattstax" -- the pride, the anger, the ambivalence, the celebratory verve -- is what Stuart hopes a wider audience will appreciate, not only about the film but about the era it captures. Making the movie, he says, "opened my eyes to the black perspective on living in America. . . . There's a guy in there who says, 'I's always being black.' In other words, it's always going to shape how you feel about everything."

"Wattstax" is many things -- a rocking concert film, a vivid cultural artifact, a nostalgic look back at a time of hope and possibility. But today it might have its most profound impact raising the consciousness of viewers of all races, to what are still the difficult and joyful realities of black life. "After 'Willy Wonka,' this is my favorite picture that I made," Stuart says proudly. "It holds up well."

"Wattstax" will be shown Wednesday on Channel 26 at 9 p.m. and Friday on Channel 22 at 10 p.m.

Isaac Hayes's performance, cut from the film in '73, can be seen in the version airing on PBS. Jesse Jackson is at left.Filmmaker Mel Stuart, left, included interviews with residents of the L.A. neighborhood of Watts, where riots had raged seven years before the concert.The documentary features then-emerging comedian Richard Pryor along with performances by such groups as the Emotions, right, who were filmed performing in a tiny Watts church.A colorful time capsule of 1970s style: Rufus Thomas sings "Do the Funky Chicken" at Los Angeles Memorial Coliseum.