By Stephen Robb
BBC News entertainment reporter at the Cannes Film Festival
A U2 concert film in digital 3D could herald a minor cinema revolution after its unveiling at the Cannes Film Festival.
Filming involved up to nine cameras with on-board computers
U2 3D has been assembled from more than 100 hours of footage shot on the band's Vertigo tour last year, with the majority coming from two shows in front of 90,000 people in Buenos Aires, Argentina.
"You have never seen 3D shot live, unscripted like this," says producer John Modell.
"We have developed some really great tools to allow you to shoot 3D live action and have it look just perfect."
Cannes journalists agree, with BBC film reporter Tom Brook saying: "I liked it because it was more than just a gimmick - it made it very intimate at times."
He adds: "They should have had cool air blowing from the front to complete the experience."
Viewers wear special 3D glasses to experience the feeling of being within the live audience, enhanced by the film's surround sound, while performers' limbs appear to come out of the screen at times.
Producer John Modell recreates a Bono move
"This process of 3D, we really feel it immerses you in the event. It brings you closer to the artist, and closer to their songs," says Modell.
He says the technology will be used to cover a sporting event, while it can also be utilised for scripted films.
"We feel that this new era of 3D is going to be a sea-change, very much like going from the silent films to talkies, or from black-and-white to colour."
The company behind the technology, 3ality Digital, approached U2 and arranged to film a single-camera test in 2005.
The result impressed the band, with singer Bono suggesting shooting the full film on the band's return to South America after an eight-year absence.
As well as filming concerts in Mexico, Brazil and Chile, U2 3D's makers shot a performance of 10 songs without an audience in Buenos Aires to get vital close-ups.
A 90-minute version is to get a worldwide release
"We just made sure we had the cameras in the right place, and we let them really get into what they do best," says Modell.
U2 3D is credited to co-directors Catherine Owens, who has produced visuals for several U2 tours, and Mark Pellington, who directed the band's One video and several films.
The film features performances of hits including Sunday Bloody Sunday, With or Without You, The Fly and Beautiful Day.
The band have seen several of the songs, and found it a "very profound experience", says Modell.
"One of the things that Bono said was, 'I've never been to one of our shows before.'"
U2 are due to attend the 60th Cannes Film Festival on Saturday.