Are HDTV and multicasting competing technologies?
This is archived content from Digital TV Facts. For up-to-date information on the digital TV transition, see the federal government’s site, www.DTV2009.gov. In some ways, yes. To provide high-definition television (HDTV) images with surround sound, broadcasters must send huge chunks of information over the airwaves. During HD broadcasts, a local station has only enough room left in the digital pipe (“bandwidth”) to provide one or two more multicast programming streams, rather than perhaps four more otherwise. A station may “downconvert” a program that was produced in HD into a lower-quality form of HD, or even into standard definition, to make room for more multicast channels. Viewers equipped with HD displays may notice diminished quality in such cases. It’s a classic case of quality vs. quantity—and a zero-sum choice. Station owners must weigh the costs and benefits of providing a single program in high-def or multiple programs in standard definition (SD). Will one show in HD bring i
Because HDTV uses more space on the broadcasting spectrum, broadcasters cannot offer as many programs when multicasting. HD broadcasts leave room for one or two multicast streams in the bandwidth. Without high definition programming, there would be room for approximately four more multicast programs. However, HDTV and multicasting can be viewed as complimentary rather than competing. This way, stations can deliver HD programs during prime time, while offering additional multicast program streams at other times in the day.
