With both installers and end users trying to get their heads around 4K technology, one Japanese company has pushed ahead with 8K resolutions, writes Callum Fitzpatrick.

4K display technology is still in its infancy – very few manufacturers have fully embraced the format, and consumers are still wary of it…if they even know it exists at all. However, while many of us are still coming to terms with 4K, Japanese public broadcaster NHK has powered on ahead, introducing its Super Hi-Vision (SHV) system, which features 8K video and 22.2 multichannel sound.

“NHK designed 8K SHV based on human cognition studies – we wanted a 2D TV system to produce the same sort of immediacy you get when observing real objects,” says NHK science and technology research laboratories senior engineer Arisa Fujii.

“To do this, we needed a display size that covers the entire human angle of view, with a pixel count that provides a realistic sense of texture. This was combined with 3D sound to make the whole experience more compelling.”

NHK showcased the power of 8K with a series of screenings of the London Olympic Games in the UK, US and Japan last year.

“We have found that it is perfect for sporting events, nature scenes in documentaries, films, educational broadcasts for schools, digital signage, digital museums and extremely vivid telecommunication services,” Arisa says. 

The SHV system has 7,680 horizontal and 4,320 vertical pixels. That’s four times the horizontal and vertical lines of current HDTVs and 16 times the total pixel count and information volume. The drawback is that this inevitably requires a substantial data rate – 72Gbps at 60fps in the case of low, uncompressed data. That is simply too much data for broadcast and can’t be realistically transmitted without substantial compression.

Consequently, NHK plans to compress the video using next-generation High Efficiency Video Coding (HEVC).

“HEVC has four times the compression efficiency of the MPEG-2 systems that are currently used for digital broadcasts. We have already succeeded in using HEVC to reduce the data rate to below 90Mbps,” Arisa says.

“That was a world first. Using the dual-polarised multiple-input and multiple-output (MIMO) and ultra-multilevel orthogonal frequency-division multiplexing (OFDM) technologies, and a transmission method such as 16 or 32 amplitude and phase-shift keying (APSK), it should be possible to transmit 8K SHV on a single terrestrial digital channel via a single relay device on a current broadcasting satellite.

“We are now studying the whole scale of the format that will be needed for broadcast – including cameras, recording, editing, compression, transmission, reception, display and sound.”

Even if SHV is considered broadcast-ready in a technical sense, Arisa explains that the technology needs to be embraced by the masses before it is a truly viable option.

“HDTV won acceptance all over the world because people weren’t satisfied by the viewing experience provided by SDTV,” Arisa says.

“That’s why we think that people will probably welcome the extremely vivid viewing experience of 8K SHV. However, timing will be an issue. Even in countries where the HDTV shift was made early, both broadcasters and viewers have only recently adapted to the major change. What’s more, there are other countries that still haven’t moved across. Therefore it would be very difficult to instantly replace HDTV with 8K SHV.”

That’s why, in the initial stages, NHK plans to offer SHV as a supplementary service alongside traditional terrestrial broadcasting.

“It is important to produce program content that people will accept little by little, starting from the early adopters,” Arisa explains.

However, for this to happen, consumers need to be able to receive and play 8K content through an affordable medium, such as a TV receiver combined with a HEVC decoder.

“The price of HDTV technologies has been reduced in recent years, so we can say that it will be only a matter of time until 8K SHV television receivers also become more affordable for consumers,” Arisa says.

There also needs to be 8K content being produced by filmmakers in the first place. Arisa explains that this can only happen if the 8K market is an attractive prospect to content producers and video technology companies.

“The development of reasonably priced receivers and high-performance production equipment depends on creating an attractive market for the makers,” Arisa says.

“For large numbers of people to desire 8K SHV, there has to be an attractive broadcasting service and great content, so we need to encourage a positive feedback loop between the engineers, media, the market and so on.”

Very few people at present, even those at NHK, have extensive knowledge about 8K SHV production or equipment. The same is true of sending content – there aren’t many places where 8K SHV can be sent or shown at present.

“Our first priority is R&D and then the diffusion of 8K SHV production equipment and transmission and screening facilities. The participation of equipment makers, TV stations, production companies, distribution companies will have to be encouraged,” Arisa says.

From looking back at the proliferation of HD video, Arisa says that it is sensible to say that 8K is a viable broadcast format, and one that could be with us sooner than we may think.

“HD receivers weighed more than 100kg and cost about 4 million yen ($AUD44,000) when they first went on the market. Today, with the spread of digital broadcasting, the receivers have not only become light and slim but the prices have dropped to reasonable levels. Like any new technology, it seemed very futuristic at first, but it didn’t take long to reach wide diffusion in ordinary homes. Looking at the speed of technological development, it is no fantasy to suggest that 8K SHV may be taken up as quickly as HD was, or even faster still.”

For now, NHK is accelerating the pace of its R&D and the installation and diffusion of facilities and public relations activities. The goal is to have test 8K SHV broadcasts operating by 2016.