Japanese broadcaster NHK said that it has successfully completed a test broadcast of "Super Hi-Vision," also sometimes referred to as 4320p HDTV.
NHK sent the video, without errors, about 4.2 kilometers from one of its rooftop transmitters. Because of the bandwidth involved, the signal was sent along a pair of UHF channels, using orthogonal frequency-division multiplexing (OFDM) and multiple-input multiple-output (MIMO).
Today's HDTVs display video at 1080p resolution, or a fraction of the resolution that NHK is proposing. Although the next-generation technology is most likely years away, the industry is quietly preparing for HDTV's future behind the scenes.
At 7,680-by-4,320, or 4320p HDTV, the Super Hi-Vision resolution far exceeds conventional HDTVs and digital cinema. Uncompressed, the video would require massive bandwidth and storage space; in 2006, however, NHK demonstrated a compressed version, using an NHK codec that compressed the video signal from approximately 24 Gbps down to 180-600 Mbps and the audio from 28 Mbps to 7-28 Mbps.
This past March, US satellite service provider DirecTV executives also said that they are preparing for the rollout of 4,000- and 8,000-line services, although Philip Goswitz, senior vice president of space and communications and technology development for DirecTV, did not say when.
DirecTV referred to the new technology as "Ultra HDTV."
To enable the transition, DirecTV sees itself migrating from Ku-band to Ka-band satellites. Ka-band satellites offer higher bandwidth than Ku-band satellites, but reportedly are more susceptible to so-called "rain fade," or a degradation of performance during rainy conditions.
"At DirecTV we see a couple of things happening," Goswitz said. "First, our subscribers are migrating away from Ku-band, and upgrading themselves to Ka-band and its HDTV services. In four or five years, our Ku-band [transmissions] could end. We are also developing the so-called Reverse Band for DBS services, and these are on our Road Map for future international services. 4000-line is exciting to us because of its image quality, and the potential for glasses-free 3D."
PCM
