I think you mean frame rate, not bit rate. See (http://en.wikipedia.org/wiki/Frame_rate). Note that 24 fps is the standard and that when the first film to be filmed at 48 FPS ((http://en.wikipedia.org/wiki/The_Hobbit:_An_Unexpected_Journey) The Hobbit: An Unexpected Journey) was previewed "the audience's reaction was mixed after being shown some of the film's footage at 48p, with some arguing that the feel of the footage was too lifelike (thus breaking the suspension of disbelief)." I would suggest staying with 24 fps and thus reducing the storage required for the film.