Japanese public broadcaster NHK is planning to give a demonstration of "8K" resolution content over at single 6MHz bandwidth UHF TV channel at the National Association of Broadcasters (NAB) Show coming up in Las Vegas, Nevada, April 5 to 10.
This will be the first demonstration of an 8K Super Hi-Vision over-the-air broadcast outside Japan, according to the NAB Show organizers. Engineers from NHK are also set to present details of a long-distance, single-channel, over-the-air 8K test broadcast conducted recently in Japan.
8K is the next-generation standard set to come after we have become bored with 4K resolution, although both are a misnomer. An 8K image is 7680 pixels wide by 4320 pixels high by (33.2 megapixels) and requires 16 times the number of pixels as the current 1080p HDTV. It is the generation after 4K, which is set at 3840 pixels wide by 2160 pixels high.
The first broadcast took place in May 2012 and was over a distance of 4.2 kilometers. Although this short distance is not practical for public service arrangements signal strengths indicated that 8K could be transmitted over longer distances, and that a terrestrial broadcast service was feasible. In a test conducted in January 2014 a compressed 8K signal was transmitted on a single 6MHz bandwidth UHF TV channel from a test station at NHK's Hitoyoshi TV relay station in Hitoyoshi City, Kumamoto Prefecture. The signal was picked up at a receiving station 27 kilometers away, the same distance that can be achieved by current terrestrial digital broadcasting.
In order to transmit the 8K signal, whose raw data requirement is 16 times greater than an HDTV signal, it was necessary to deploy additional technologies These include ultra multi-level orthogonal frequency domain multiplex (OFDM) transmission and dual–polarized multiple input multiple output (MIMO) antennas. This was in addition to image data compression. The broadcast uses 4096-point QAM modulation and MPEG-4 AVC H.264 video coding.
NHK has been developing 8K technology for several years but with 4K television sets only just going on sale and still expensive it may take some time for 4K to displace HDTV. Flagship broadcasting events such as the Olympic games or the soccer world cup often do much to stimulate switchover. Tokyo's successful bid to host the summer Olympic games in 2020 is seen as the event which may mark the beginning of the 8K era although it remains open to question as to whether all consumers will find it useful to go to such high resolution.
At the NAB event NHK's exhibit will feature a presentation theater with a 350-inch screen for viewing Super Hi-Vision content with 8K video projection and full 22.2-channel sound reproduction, including highlights from the Sochi Winter Olympic Games.
NAB will also host an 8K video camera that weighs less than 4.5lbs (2kg), the world's first 8K-capable real-time HEVC encoder, and a display-integrated immersive sound system providing virtual representation of 22.2-channel sound for a domestic environment.
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