The transient nature of movies on the film festival circuit often gets overplayed.

There are a number of instances of this at Tribeca: Steven Soderbergh's "The Girlfriend Experience" will have its world premiere after the director screened a work-in-progress cut during the Sundance in January. However, the running time hasn't changed, and one imagines the content hasn't, either.

Independent horror filmmaker Ti West raised a stink [1] last week about the four minutes excised from his Tribeca entry "The House of the Devil" -- a candid admission that resulted in his producer's insistence on canceling any other immediate interviews, including one with yours truly -- but ultimately, the lack of these scenes doesn't ruin West's delightfully freaky story of Satanic worship and college roommate angst.

Nicole Opper's documentary "Off and Running," however, presents a different situation. The fascinating story of an adopted African-American teen raised by lesbian Jewish parents in Brooklyn, it runs 75 minutes -- but the filmmaker will have to snip it down to just under an hour for airing on public television later this year.

Fortunately, Opper has some smart people on her side. "Off and Running" is one of three features screening at Tribeca that went through the Tribeca All Access program in 2008. The week-long event allows filmmakers to discuss their unfinished projects with a number of industry and filmmaker veterans.

"It's very much like a training ground," Opper said. "We had an intense pitch session on the first day that helped me tremendously. They give you huge amounts of constructive criticism."

Applying a classically verité approach, Opper allows Avery's story to unfold with the sort of naturalistic drama usually associated with scripted features. It's a startlingly sharp portrait that avoids the trappings of talking heads. Instead, Avery's distinctive situation unfolds through her own eyes.

She's a fantastic on-camera character whose surprising eloquence never falters, even as her family situation grows increasingly complex. "She was such a compelling character,” says Opper, a graduate of NYU's film production program, who first discovered Avery while teaching at the Hannah Senesh Community Day School. “It was really several months later that she confided in me that she had been thinking about writing a letter to her birth mom."

The fallout of that decision forms the central thrust of Opper's movie, and the primary reason why Avery's adopted parents chose not to sit through it during the Sunday screening. "They said it's too raw, too present," Opper said. "They're still healing this big breach that happened. It's going to take some time."

The movie's conclusion leaves Avery's relationships to several people in her life up in the air, which was a creative decision that Opper and her subject mutually agreed on. "By the end of the film, she has come a long way in her commitment, and we agreed that was the central part of it," Opper said. "It seemed like the best way to leave it."

Where does that leave "Off and Running"? In a good place, most likely. The director has already met with distributors about a possible theatrical release, and received suggestions for the television cut from the Documentary Video and Community Media Center. But first things first: Sunday's premiere was sold out -- and filled with teenagers in attendance as part of the Tribeca Youth Screening Series.

Regardless of what version of the movie finally comes out, the combination of community forces behind its existence makes "Off and Running" the quintessential Tribeca product -- no matter what different story you hear from the glitzier premieres and difficult productions.

But make no mistake: "The Girlfriend Experience" and "The House of the Devil" are pretty good, too.