On the surface, Apple's concept for what it calls iTunes Replay seems uncomplicated and reasonable enough buy a digital copy of a movie from our iTunes Store and watch it anytime, anywhere on any device capable of downloading or streaming it. The movie would be stored permanently in its upcoming iCloud service. But, as with many such concepts involving the motion picture industry, Apple's plans have run into a copyright roadblock. According to CBS-owned CNET, the technical media website, four of the six major film studios -- have not signed on to iTunes Replay out of concern that it might breach their exclusive streaming deal with HBO. Under that deal, HBO has first dibs to stream movies from the studios after they are released on DVD. It is not clear whether Apple now intends to go ahead with plans to implement iTunes Relay this fall.