Ultra HD: Is It Soup Yet?
Ultra HD can be much more than simply 4K resolution (more precisely, 3840 x 2160 in the consumer arena4K in the pro world, including digital cinema projection, is 4096 x 2160). It also has the potential to offer a wider color gamut, an increased color bit depth, and less aggressive color subsampling. If that string of technobabble sounds intimidating, it simply means that in addition to more pixels, Ultra HD could provide a wider and richer color palette than does our current HD standard.
There is an informal industry roadmap leading to eventual implementation of the full potential possible with Ultra HD, but at present it’s something of a Yellow Brick Road, with lots of adventures strewn along the way. For example, the widest suggested color gamut, known as REC2020, may not even work, though the technical explanation for that is beyond the scope of this tome. The most likely practical candidate could be P3, the gamut currently used for theatrical digital projection (also known as DCI, for Digital Cinema Initiative). You can be certain, however, that no current consumer Ultra HD source material (limited as it is) offers any of Ultra HD’s potential benefits beyond 4-times the pixel count of our current 1080p HD. The color from these sources will be limited to our current REC709 HD standard. Wider and deeper color will (might?) come later.
Will an Ultra HD set you might buy today allow for all of these advanced color capabilities, when and if they come? The answer is no and yes.
First, the “no” side. For any true Ultra HD set produced before the 2014 model yearwhich means most of the sets on dealers’ shelves and in their warehouses as of mid May 2014the only Ultra HD advance you can be sure of is a 3840 x 2160 pixel count. Yes, such an early UHD set might well have a control in the user menu offering a selection of wider color (these come by various names, such as Color Gamut, Color Space, Wide Color, etc.), but so do many current 1920 x 1080 sets. In either case, none of these wider, ad hoc color options matches the color in any current source, 2K or 4K, nor can they be expected to match new color standards for UHD. If you want accurate color with today’s source material you should turn any such control to whatever selection conforms to the current REC709 color standard (sometimes, but not always, labeled “Normal”). If an Ultra HD source with any of the advanced color features arrives at such an Ultra HD set in the future, the set will likely not handle it properly. It may provide a picture (rather than a blank screen!), but the color will be wrong. Whether or not the color errors will be visibly objectionable is at present unknown; though most likely only serious video enthusiasts (like us) will complain.
The “yes” answer assumes you will buy one of the new 2014 or later Ultra HD sets, which are only now just coming to market. For maximum future proofing, however, (though expecting future proofing beyond, say, three to five years is a fools errand in today’s fast changing tech environment) you need to confirm that such sets offer full HDMI 2.0 capability (there have been partial implementations of HDMI 2.0 in a few Ultra HD displays released to date). In addition, the set must have HDCP 2.2 (a copy protection scheme) and HEVC (High Efficiency Video Codingthe compression format currently planned for use with Ultra HD source material, though at present all such material is still encoded in one of the current HD compression schemes, such as H.264).
Don’t automatically assume that all 2014 Ultra HD sets will incorporate these new features. And your friendly neighborhood Spider-Man with a video sales associate day job is unlikely to have an answer (though he or she will certainly try to wing it). We’ll be providing this information in our upcoming Ultra HD reviews, though it will have to come from the manufacturer; we won’t be able to confirm it until compatible test material is available. And even if the set has all of these features, we suspect that the Ultra HD situation will be quite fluid for some time.
Might there be an adapter made available to allow a pre 2014 Ultra HD set (or even post 2014 sets that don’t fully comply with as yet unanticipated requirements) to properly handle an Ultra HD source with a new color format or some other as yet undefined must-have features? Possibly, but we currently know of only one manufacturer talking about this issue. In its early Ultra HD sets Samsung incorporated an external “One Connect” box. All of the inputs were on that box, and the box itself connected to the set through a single cable. If a format update comes along that the current set can’t handle, only the box needs to be changed. Since this is an expensive solution, however, some of Samsung’s newer, less pricey Ultra HD sets have normal inputs, but also include a port for a future, optional One Connect box. The latter would then allow for upgrades that the present inputs can’t handle. You’d only have to buy a One Connect box, rather than trash the entire set. (In either case, however, there can always be possible updates that such a converter box will not accommodate. These could include future improvements to the panel itself or its drive circuitry, which might well require a new set if you wanted to reap the benefits.)
This discussion was inspired by a recent article in the Wall Street Journal that addressed the pros and cons of a consumer making the move to Ultra HD in 2014. But the writers involved needed to do more fact checking with experts. One comment in the article stated Ultra HD offers a "greater array of colors and...sharper contrast..."? Without the information above (likely beyond the pay grade of the writers), this is misleading at best. We’ve slogged through the color issues above. And unless we’re talking about Dolby’s new HDR (High Dynamic Range) technology, which may eventually find its way into the Ultra HD mix, there’s nothing inherent in Ultra HD that will improve image contrast. (And don’t hold your breath for HDR. Not only must the source material be specifically encoded for it, but I suspect TV makers will want to save HDR for a future Next Big Thing after Ultra HD becomesthey hopeas ubiquitous as “Full (1080p) HD” is today.
If this sounds like 4K is currently a bit of a moving target, it is. Ideally, all of this would have been settled before Ultra HD was ever announced to the public. But with the fading of 3D as a sales incentive, and the HDTV flat screen market approaching saturation, a new buzz is needed to get buyers into the stores. That’s not necessarily a bad thing, and most of us here at Sound & Vision are excited about the promise of Ultra HD. Early adoption is always something of a crapshoot: I was once the proud owner of an Elcaset tape deck. But it’s early adopters that convince manufacturers they’re on to something that the wider public will embraceif the price is right.
Click here to participate in our 4K/Ultra HD poll.