U2 were committed to preserving the film's 3D format and decided to only release it in digital 3D. To help promote this film format, "U2 3D" was first screened at the 2007 Cannes Film Festival on May 19, 2007. It was one of nine films to be screened out-of-competition at the 2007 festival, and was the first live-action 3D film shown at Cannes. Following a brief song performance by U2 at the festival, the film was screened at midnight inside the Palais des Festivals et des Congrès. At the time, the 3D post-production process was incomplete; therefore, a shortened, 56-minute version of the title was screened, featuring nine of the completed version's 14 songs. Originally scheduled for the third quarter of 2007, the completed version premiered at the 2008 Sundance Film Festival on January 19, 2008 at the Ellen Eccles Theatre. The theater incorporated a customized sound system designed especially for the premiere with new Dolby 3D technology, which John Modell referred to as "the most high tech film screening that's ever been done in history."