Like therapeutic drugs, new versions of HD take many years on their journey from concept to the consumer. NHK, the Japanese national broadcaster, first transmitted Ultra HD pictures, at a resolution 16x greater than the current top end 1080p, over a 260Km fiber in 2005, yet only now are standards crystallizing, and it is unlikely to reach TV sets until at least 2016. However, this version of Ultra HD, known as 8K at a resolution of 7680x4320 pixels, is being used in some digital cinemas, as is the lower ultra HD standard of 4K, at 4096x2160 pixels.
NHK has stated it wants to start broadcasting in 8K Ultra HD after 2016, but this will require standardization of these higher resolutions, as well as harmonizing these with 3-D, which broadcasts, in effect, two simultaneous HD streams. The key bodies involved in Ultra HDTV standards formation are the ITU (International Telecommunications Union), the European Broadcast Union (EBU), both based in Geneva, and the SMPTE (Society of Motion Picture & Television Engineers) in New York.
Of these, the ITU has been preparing recommendations for both Ultra HDTV and 3DTV through its so called ITU-R Working Party 6C (WP6C), which has been focusing on program production, on the format for exchange of content between systems or broadcasters as well as for archiving. The WP6C would have liked 3DTV and HDTV to converge into a common global standard at this stage, but, as is so often the case in the broadcast world, this will not be possible because of the need to accommodate legacy digital systems from different regions, often developed many years ago. The WP6C gives as an example here of the fact that because of differences in electricity mains frequencies dating back over a century, TV systems have to accommodate both 50Hz and 60Hz supplies today.
As a result, standardization of 3DTV and Ultra HD will proceed as separate exercises in parallel, although drawing them together as far as is possible. For 3DTV, the group has been focusing on making and exchange of TV programs, and has concluded that this should be done by pairing up one of the existing HDTV formats, presenting final decisions at the next WP6C meeting in spring 2012.
On the Ultra HDTV front, the group is preparing a recommendation for the format of both the 4K and 8K Ultra HDTV systems. These have respectively 8 megapixels and 32 megapixels per image, as had been agreed previously, with an extended color range. It has also been decided to support an additional higher picture rate of 120Hz, which was deemed to improve “motion portrayal.”
There has also been a focus on “color encoding,” which enables bandwidth to be reduced by a half or a third without affecting image quality. This can be done because the eye is less sensitive to color than to brightness, and the color encoding exploits this.
These emerging standards will then be discussed by the SMPTE and EBU at a summit in May 2012 in Geneva, which will also set the tone for increasingly close collaboration between the worlds of Information Communication Technology and broadcasting.