Make no mistake about it, as the bandwidth belt tightens
around cable, carriers are grasping for ways to cram more channels into an increasingly small space. Reportedly, Comcast Media Center has devised a method to stuff three HD signals into a single 6MHz carrier, which is typically just enough to handle two HD channels without picture quality taking a dive. Though the process sounds quite technical, the long and short of it is that a "second-pass MPEG-2 encoding system from startup Imagine Communications" is reportedly being used to "stack together three signals at variable bit rates into one 6MHz QAM channel." Of course, it's hard to say if this clever methodology results in noticeably poorer picture quality, but unless something drastic
happens in the world of coax, you can count on seeing a whole lot more where this came from.