Worried About Bandwidth for 4K? Here Comes 8K!
Japanese public broadcaster NHK will be launching a channel in 8K "Super Hi-Vision" in a little over a year's time, following two-and-half years of testing a satellite-delivered 8K TV channel. The broadcaster announced the December 2018 launch at the MIPCOM UHD event in Cannes yesterday.
NHK will also be growing its slate of 4K UHD content, with plans to offer 18 hours of 4K content daily on its existing 4K channel. The goals for its 8K channel are only slightly more modest at 12 hours and ten minutes per day delivered in 8K resolution. NHK is investing heavily in producing more content at these resolutions to be able to quickly develop a library of content and support these channels.
NHK's "Super Hi-Vision" format uses 8K resolution (7680 x 4320 pixels), or sixteen times the resolution of a 1080p full HD picture. The broadcaster has been offering mostly non-fiction 8K content on its test channel, including coverage of the Olympic games and music concerts of various kinds. More recently it showcased a nature and wildlife documentary, coverage of a ballet and cityscape footage. It's typical footage for test channels, to show the visual quality of a high-resolution format, and is not that different from the kind of content that was used to sell HDTV. But it's far from mainstream programming.
In fact, penetration of 8K TVs and reception equipment is so limited -- even in device-crazy Japan -- that NHK installed viewing stations in Japan during the Rio Olympics, so that people could sample the technology. Why then move forward with 8K broadcasts? NHK is a public broadcaster, with funding and a public service mandate. It also has a long history of pioneering new video technologies and has an active research and development division.
8K also faces two other challenges. Firstly, being able to appreciate even a 4K channel requires a TV screen of about 55-60 inches. Anything less, and the difference between 4K and HD is difficult to appreciate fully. To differentiate 8K from 4K, you would probably need a screen of about 85 inches, and you would need to sit about five to six feet away. In many North American homes that might work, but in Asian and European cities it will limit the addressable audience significantly.
Secondly, pay-TV providers are still struggling to handle the bandwidth requirements for 4K channels today. 4K requires bit rates of between 15 Mbit/s and 25 Mbit/s for high-quality, fast-motion content like live sports. 8K could push those requirements up to 80 Mbit/s or even 100 Mbit/s for each channel/stream. Most broadband and pay-TV networks are not able to support those kind of bit rates, particularly when you factor in multiple members in each home viewing multiple channels or streams simultaneously.
As such, 8K is likely to be more of an experiment for now, with some serious questions about its applicability as a traditional linear TV delivery format. But it can be used for other purposes: NHK highlighted its productive video uses, such as in healthcare. NHK demonstrated 8K's use in filming microscopic footage for medical research purposes. (See Defining Productive Video.)
Virtual reality (VR) is another area where 8K could be useful. The nature of VR requires the viewer to essentially zoom into a part of the picture, which means that resolution and visual quality suffers. To create a rich, immersive experience, visual quality is very important. 8K can help, since even zoomed in at 16X resolution, the viewer is still looking at a full HD-quality picture.
While I would expect more experimentation in this space, I doubt 8K will emerge as a viable TV format, even in the next few years. The cost-value equation doesn't make much sense, specially as the industry is still feeling its way with 4K.
However, 8K could have an impact in areas like VR and productive video, where the higher resolution makes a major difference in specialized use cases. We may also see more production and coverage in 8K, but distribution in down-converted 4K. This creates a slightly better experience for the viewer and allows broadcasters to build a library in 8K in case the format does take off somewhere down the line.
— Aditya Kishore, Practice Leader, Video Transformation, Telco Transformation