Cinemax: All HD On September 1 The channel says it will be the first premium channel to do so. By Swanni HBO has announced that Cinemax's main channel will go all-HD on September 1. The network says Cinemax HD will be the first premium subscription channel to broadcast an all-HD lineup. Other channels, such as HDNet Movies and MGM HD, also broadcast an all-HD lineup. HBO, which owns Cinemax, says the movie channel's on-air promos and short features will also be in high-def. "As the No. 1 movie service, Cinemax subscribers have come to expect a picture of the highest...