4K at NAB with Bob Pank

Bob Pank#

Author: Bob Pank#

Published 1st May 2013

As we head once more to NAB you may wonder what this year’s big thing will be. I put my money on 4K. As I write there must be many exhibitors polishing up their ‘4K solution’ message, ready for their customers at the show. With the extraordinary situation of screens costing more than cameras, a viable business model clearly remains far off. But, to be fair, the technology has to start somewhere and screens and cameras seem to be the genesis. In between there has to be a production and post workflow, as well as a delivery system. Hopefully we will see a whole lot more of that in Las Vegas; otherwise 4K will not be flowing anywhere soon.

The talk is all about 4K for TV. Its image size of 2160x3840 sits midway between 1080x1920 HD and 4320x7680 originally called Ultra High Definition Television, and later Super Hi-Vision, by its inventors at NHK. In recent months both 4KTV and SHV have been bundled under the UHD banner, which seems unnecessary and will cause confusion. (For reference, in the digital cinema world its 4K is 4096x2160, a 2x2 version of its 2048x1080 (2K) – both slightly bigger than TV’s 2K and 4K.)

With 4KTV being in the mid-size between HD and 8K UHD, it could have a serious identity problem. What is it for? Is it TV – the thing we watch at home – or cinema with a huge screen and dedicated viewing area? With digital cinema making fantastic progress replacing film and bring much improved quality and reliability, just its with 2K-sized image, why should we want four times that picture detail to watch in our homes – most of which are smaller than cinemas? This is a matter of screen size, real estate and the way we watch TV and movies.

Many HDTV viewers find 42-inch screens work well for them. Logically, it follows that 4KTV, with four times the picture area, should be viewed on an 84-inch screen, and I’m sure there will be plenty of these to view at NAB. Sony showed a very well produced show reel at IBC where you could look, and then look closer and see more and more detail. You could look around the picture and study the detail; a rather different experience to SDTV where the camera selects the one object you are meant to look at. HDTV allows us a bit more freedom to look around. That freedom is dramatically multiplied in 4KTV – and even more so in 8KTV... on your 168-inch screen, perhaps?

It’s all very well admiring the huge screens in the vast halls of the Las Vegas Convention Center but think about it, how would it look in your sitting room, or wherever you watch your TV? Maybe you think you’ll manage with a smaller screen – and why not? The 84-inch LED models retail for around £20,000... and so are clearly not aimed at the mass market. I’m sure they will come down but it surely won’t ever get low enough to appeal to the wider consumer market.

Fortunately Harrods was showing a range of 4K screens. This was a rare opportunity to see many different brands side by side. Yes all the 84-inch models looked fantastic and the super rich were, reportedly, buying. However the screen that really stood out was hailed by LG, its maker, as ‘The World’s First 55-inch OLED TV’. Not only did it have beautiful blacks and very high contrast, but pretty much a 180-degree viewing angle. The screen was just 4mm thick, including its carbon fibre backing, and the whole thing cost just £10,000. This is a great improvement, not just for the better contrast and picture, but it did the job in a smaller package that many more people could accommodate at home.

To see all 8.2 million of 4KTV’s pixels you need to get sufficiently close to the screen, but not too close. A survey in the USA found that HD viewing distance was generally around 2.7 metres (9 feet). This may be more down to the furniture than TV technology! My web research threw up widely varying recommendations but the one I trust most is at videograndpa.com showing test results from NHK, and their graph indicates a 1.5 x screen height (H) is best. The 4K screen size calculator shows recommendations from NHK, SMPTE and THX that widely vary. For example, for viewing at 9 feet it indicates 146, 73 and 90-inch screens respectively. Of the three, NHK’s is based on actual experience and so I think is nearest to the best result. But even taking the smallest, a 73-inch screen is still a monster. Either we retain our 9-foot distance and endure the monster, and its costs, or we move in a lot closer. The probability is that we’ll buy an affordable size and sit 9 feet away and not see the full detail of 4K.

Viewing at NHK’s recommended distance to the screen creates a wide viewing angle, somewhere about 50-degrees, and means you cannot concentrate on all the screen at once, you start to look around – like real life! This is a different experience to HD. But the big question is will the public actually buy at least a 55-inch screen, re-arrange the furniture and view as closely as recommended? I think that’s unlikely. Use in home cinema is much more appropriate while keeping our SD / HD set to glance at across the room. While at NAB, visit NHK (booth: N231) and anyone else showing 8K. Ignore the crowd standing 9 feet back and watch at the recommended distance of 0.75 x screen height. They usually have an 85-inch screen so try viewing from about 31 inches (0.8m) away, creating a 100-degree viewing angle. My feeling is this is a bit too close, but 4 feet (1.2m) is fine.

Both 4K and 8K UHTV require a great deal of further development to provide a complete scene-to-screen workflow. On the face of it the benefits of higher resolution are easy to understand and they can provide clear sharp pictures at a wider viewing angle, and so deliver a more absorbing experience – but not at a nine-foot range. But will 4K deliver a sufficiently enhanced domestic experience over HD to make it worth the engineering effort and customers’ money? There are also other possible directions for development, such as higher frame rates, which could enhance viewers’ experience without having to buy a bigger screen. We can see for ourselves in Las Vegas!

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