If you've been in the market for a new TV recently, you've undoubtedly heard the term 4K. You may have also heard the term "UHD," which just stands for Ultra High Definition.
A lot of people seem to think these two terms are interchangeable, but they're not: Every UHD TV is a 4K TV, but not all 4K TVs are UHD TVs. In fact, there are no true UHD TVs even available yet. 4K options from 2013 and 2014 may boast the new 3,840 x 2,160 resolution, but they're HD TVs in every other way.
So then what's missing from the puzzle? Well, pretty much everything—aside from resolution—that makes any TV a great TV.
Ultra High Definition formatting is poised to roll out in three separate phases, and Phase 1 (4K resolution with no improvements to color or frame rate) has already happened. But within the full scope of Ultra High Definition technology, 4K resolution is perhaps the least exciting achievement. In truth, the jump from 1080p to 4K is only the tip of the iceberg.
Where We've Been, Where We're Headed
The short story here is that there are certain minimum requirements for a TV to be considered an "Ultra High Definition TV," and the 4K TVs produced in 2013 and 2014 didn't meet those requirements.
This isn't new: Televisions went through the same process about 15 years ago during the upgrade from Standard Definition (SD) to High Definition (HD). The jump from Standard to High Def was more than a matter of upping resolution or expanding the aspect ratio from 4:3 to wide-screen (16:9). HD added 1,024 luminance samples (compared to SD's 720), while gradually introducing better chroma (color) information and progressive (versus interlaced) refresh rates.
The easiest way to understand the format shift is like this: High Definition enabled content creators and broadcasters to do less compressing of their original information before it got to your TV, whether it was disc media or over-the-air broadcasting. The key ingredient here is the preservation of information during during its delivery, and Ultra High Definition is the next evolutionary step.
By now you've probably guessed that Ultra High Definition will (and does) encompass a lot more than just a leap from 1080p (Full HD) to 4K resolution. Fortunately, this time around we have a rough outline, called the UHD Roadmap, that outlines how Ultra High Definition will filter into hardware and software specifications for the next 5-6 years.
There's still some debate about the final specs, which are peppered with question marks and often include mere suggestions. In short, though, the Roadmap says this: By the year 2020, UHD TVs should encompass 8K resolution (twice the sharpness of current 4K resolution), a speed of 120 frames per second (twice the refresh rate of most Full HD televisions), and a color space called Rec. 2020, which offers about 40 percent more color than current Full HD televisions.
The most important thing to take away from this is that the path to fully realized Ultra High Definition will mean moving through three phases—and we've only made it through Phase 1.
All of the 4K TVs released in 2014 adhere to Phase 1 standards, which basically only requires a native 4K (3,840 x 2,160) resolution. Over the next five years, we'll continue to see improvements in other areas of TV performance—and quite a few of them should trickle into the market this year.
As of this summer, we're somewhere between Phase 1 and Phase 2, moving past the resolution improvement from Full HD (1080p) to 4K (2160p) into other (more exciting) areas.
If Phase 1 means improved resolution, Phase 2 means the first major improvements to contrast, color, and "speed." This year's crop of TVs will define whether requirements for Phase 2 are fully or only partially realized.
If all these specs leave you scratching your head, don't worry; there's a new organization called the UHD Alliance that's stepping in to help consumers understand where TV content and hardware is headed. More importantly, the organization is designed to make sure manufacturers play by the (same) rules.
The UHD Alliance
Starting at this year's CES, a slew of new terms emerged that made a concept like "4K resolution" seem simple by comparison. Thanks to the recently announced UHD Alliance, however, we now have a standardized glossary of terms with which to categorize the 2015 TV lineup.
In the simplest terms, the UHD Alliance is a collaboration between content creators like Walt Disney Studios and Twentieth Century Fox, content providers like DIRECTV and Netflix, and TV manufacturers like Samsung, Sony, and Panasonic.
The Alliance was announced at CES, but the rules it intends to enforce have been in place for the last couple of years, via the UHD Roadmap. The Roadmap is just a set of rules for TV performance, and the UHD Alliance was created to make sure manufacturers develop products that follow those rules.
Fortunately, the UHD Alliance established a glossary of terms to help break down current and upcoming improvements to UHD technology. To make things easier, these requirements can be separated into four categorical improvements: resolution, contrast, color, and speed. The following specs must be met in order for a television to be considered Ultra High Definition:
4K Resolution - This resolution spec is the first and most basic requirement. It means that a 2015 UHD TV's native resolution (pixel count) must be 3,840 horizontally and 2,160 vertically. So far, this is generally the only improvement that 2013/2014 4K TVs have made.
High Dynamic Range - For this contrast spec, dynamic range refers to luminance, or the amount of light the TV is capable of producing. The High Dynamic Range (or HDR) specification is still being finalized, but current trends suggest that HDR-capable TVs will need to be able to produce "specular highlights" that are at least 1000 nits bright.
Wide Color Gamut - This color spec means that a TV adheres to a wider color space than Full HD TVs were capable of, allowing for more vivid colors and better color gradation. Like with HDR, the exact parameter coordinates are still being finalized, but it's likely that the DCI P3 color gamut will be the requirement/standard for UHD TVs, at least in 2015.
High Frame Rate - This speed spec refers to the refresh rate (or "pictures per second") the TV is able to produce, i.e. how many times per second the image is refreshed. In 2015, we expect UHD TVs to be capable of 4K resolution at 60 frames per second, and Full HD (1080p) resolution at 120 frames per second.
So what's the status?
If you're concerned that Ultra High Definition TVs are going to be super expensive, don't take out a second mortgage just yet. For one thing, 4K Resolution is already here, and it's been available in the US since late 2013.
High Dynamic Range is less ubiquitous, but a lot of manufacturers have already made headway in achieving this spec. Last year, companies like Sony, Panasonic, Vizio, and Toshiba began implementing the necessary hardware (full-array backlighting with local dimming) into premium models.
The Wide Color Gamut spec is likely to draw the biggest expense. To achieve the color spec requirements, manufacturers are implementing a new technology called Quantum Dot, which allows traditional LED TVs to achieve never-before-seen levels of color vivacity. However, a new panel type called OLED is already capable of expanded color.
Finally, 4K TVs capable of High Frame Rate were actually already available last year. The 2014 Vizio P Series supported 1080p at 120 frames per second, and we expect that functionality to be standard in most upcoming 4K televisions.
If you're looking to buy an affordable 4K TV, the best place to start is with those released in 2014.
We've reviewed a bunch of them, but you might be a little disheartened to know that none of them meets the Phase 2 requirements.
That's not to suggest last year's 4K TVs aren't worth buying, but merely that they offer only a small slice of the full UHD experience. As mentioned, most 4K TVs simply increase the pixel count without improving the quality of those pixels—whether through more vivid colors, better contrast, or higher refresh rates.
While the UHD Alliance intends to oversee 4K compatibility of streaming content (like Netflix) and disc media (like Blu-ray's UHD standards), the term "future-proof" remains a relative term when it comes to TVs.
Here's the gist of it: If you want your 4K TV to be "next-generation" in more ways than pixel count, you'll need to hold off buying one for the time being. But if you simply want greater resolution and want to be able to view native 4K content (albeit with last-generation color/contrast/speed), there are plenty of options available to you right now.
When (and How) to Buy
The coming improvements to UHD televisions are going to make the 1080p to 4K increase in resolution seem like small potatoes. Eventually, content available from streaming providers like Netflix, or encoded onto discs via 4K Blu-ray, will be able to take advantage of intense new colors and carefully crafted contrasting elements. With the right TV, it will look truly incredible.
The UHD Alliance should make picking a "true" UHD TV—versus one that's essentially an HD TV with more pixels—easy. The coming enhancements to color, contrast, and speed are what's truly exciting about Ultra High Definition.
So here's what to do: If you're planning to buy a new TV soon, buy a decent 1080p model. Otherwise, you should wait and buy a true Ultra High Definition model later this year. Unfortunately, the 4K TVs of 2013/2014 generally offer no standardized improvement except higher resolution, and will be quickly outpaced in terms of their full abilities.
That said, if you already bought one of those 4K TVs, don't worry. By the time you're ready to upgrade, Phase 2 UHD will be much more affordable, and content will be abundant.