Tribeca Film Festival dedicated to Boston on opening night

The Tribeca Film Festival opened in a spirit of brotherly love -- both on the screen, and in spirit for the people of Boston.

Richard Belzer began by dedicating this year's festival, the 12th annual, to Boston following Monday's deadly bombing at the Boston Marathon. Tribeca is no stranger to such horror: It was founded by Robert De Niro and Jane Rosenthal after the Sept. 11 terror attacks as a way to revitalize downtown Manhattan.

"Tonight, we're all Bostonians," said Belzer at the Tribeca Performing Arts Center.

Belzer, De Niro and Rosenthal introduced the festival's opening night attraction, the documentary "Mistaken for Strangers." It was made by Tom Berninger, brother of the leader singer of the Brooklyn indie rock band the National, Matt Berninger.

Though an amateur filmmaker, Tom Berninger filmed his experience as a roadie on tour with his older brother's band. He called an "a small, little, lo-fi thing" in his brief remarks before the film played.

But the humble "Mistaken for Strangers" delighted the star-studded Tribeca crowd in its comic, warm portrait of a brotherhood divided by fame.

The younger, somewhat slovenly and unorganized Berninger cuts a very different figure than his older, intense and brooding brother. More of a "metal head," he joins The National on tour in Europe looking to party like a rock star, only to find his brother's band is more, as he says, "coffee house" than all-night bar.

The film chronicles the siblings' relationship, particularly showing Tom Berninger as the uncertain, lesser-accomplished underdog between the two. It's less of a behind the scenes document than a quirky, oddly moving film about the making of a film. In the opening scene, Matt Berninger chastises his brother's silly, Chris Farley-like interview questions: "Do you have any organization and plan for this film?"

Following the screening, The National performed at an after-party at the Highland Ballroom. It's not the first time Tribeca has begun with a concert and documentary pairing. In 2011, the festival opened with Elton John performing after Cameron Crowe's music documentary "The Union."

When asked about what the festival is like for him, De Niro told CBSNews.com, "Well, part of it is stressful. The other part of it -- fun...informative. Seeing movies for me that I'm not able to see before...Basically I enjoy it."

Tribeca runs through April 28.