What Is 4K (Ultra HD)?

Just when you thought it was safe to buy a 1080p HDTV, along comes another new video format. In fact, you may have seen a number of new TVs, camcorders, and other products sporting a 4K logo, and movies shot in 4K have been playing at movie theaters for years. But what exactly does 4K mean (aside from the stock memory in a Radio Shack TRS-80, for the aging geeks like me in the audience)? Is 4K something you can get today, or at least soon enough that you should hold off on buying, say, an HDTV or Blu-ray player? Is it something you'd even want? Here's everything you need to know about 4K—for now, at least. 

What Is 4K?

Ultra HD (4K), or Ultra High Definition, is the next big step in HDTV resolution. The Consumer Electronics Association (CEA) defines an Ultra HD television as one that displays at least 8 million active pixels, with a lower resolution boundary of at least 3,840 by 2,160. There are multiple varieties of 4K digital content ranging from 3,840 by 2,160 to 4,096 by 3,112, but the 3,840 by 2,160 resolution is the most consistent number we've seen and the standard resolution most UHD/4K HDTVs and monitors have settled on. It's a nice, even number, doubling the horizontal and vertical pixels offered by 1080p (1,920 by1,080 pixels), which itself became the standard for high definition.

Collectively, the format was originally known as 4K, and while the CEA officially changed its designation to Ultra HD (UHD for short), the 4K label appears to be sticking. Either way, this is a different thing from 48-frames-per-second video, which made news last year thanks to Peter Jackson's The Hobbit: An Unexpected Journey and The Hobbit: The Desolation of Smaug. (For more on those, read 'The Hobbit' at 48fps: Frame Rates Explained.)

How Is 4K Different Than 1080p?

Depending on the variety (discussed above), 4K generally offers four times the resolution of standard 1080p HDTVs. Even so, 4K content will still be compressed for home use, as an uncompressed two-hour movie playing at 30 frames per second would require 55TB of storage just by itself, according to an excellent postfrom Michael Cioni, who acted as digital intermediate supervisor on The Girl With the Dragon Tattoo.

4K video also takes a solid 1Gb-per-second connection for reliable playback (unless it's compressed in some way), which means fast hard drives and faster-than-usual Internet and network connections. The HDMI connections on your current devices might not be enough to show 4K video at its smoothest; most entertainment devices and HDTVs use HDMI 1.4 which supports an Ultra HD picture at 30 frames per second. HDMI 2.0, which is starting to appear on most 4K HDTVs, supports Ultra HD at 60 frames per second. Like the display technology itself, it will take some time for the HDMI standard to become common enough for both HDTVs and media players.

In terms of screen real estate on a desktop, 4K makes a tremendous difference; check out the Editors' Choice Dell UltraSharp 32 Ultra HD UP3214Q$2,499.99 at Dell if you've got the cash to drop. But even when watching movies, it can be pretty clear. While some regular viewers struggle to see the difference between 1080p and 720p, at least in smaller television sizes, it's much more obvious on 50-inch and larger TVs. 4K is another significant jump still in terms of clarity and detail, especially since people are becoming more and more used to incredibly tiny pixels found displayed with today's Retina-style HD screens on mobile gadgets.

What 4K HDTVs Are Out There Now?

The third round of 4K HDTVs are already hitting the market, and at much lower prices than they were last year. Plus, they're coming from big-name vendors like Samsung, Panasonic, Sony, and LG. Now that there are 4K HDTVs in the low-to-mid-four-figure range—still too dear for most of us, but not unlike what big-screen plasma TVs cost in, say, 2005—it's more realistic to look at them now, at least from a hardware standpoint.

For example, last year we tested the excellent LG LA9700 series of 4K HDTVs ($6,500 for the 65-inch 65LA9700$4,299.00 at Dell). It features an outstanding 3,840-by-2,160-pixel picture, clear audio output thanks to a motorized, retractable speaker bar, and plenty of Web apps and connected TV features. More recently, we've reviewed a newer and lower-cost 4K LG, the $4,300 65UB9500$2,699.00 at Dell, as well as Sony's speaker-clad, $5,000 XBR-65X900B$3,798.00 at ABT. Both delivered killer 4K resolution in our tests, but had troublesome black levels compared with top-of-the-line 1080p panels.

Is There Even Any 4K Content You Can Watch on an HDTV?
In a word: barely. In a few more words: Sure, sort of. Back in 2012, the first 4K digital movie available for purchase was TimeScapes, a beautiful 50-minute film of night sky cinematography. It was shot on a RED Epic camera (pictured below) in 4,096-by-2,304-pixel resolution. A $9.99 1080p copy is available on iTunes, but full 4K versions come in $99 and $299 USB-stick varieties, with an even sharper picture on the $299 version.

What else? Netflix has rolled out House of Cards and some nature documentaries in 4K; it requires at least a 25Mbps home connection to watch in that resolution. Sony offered the $700FMP-X1 Ultra HD Media Player last year and offers the $500 FMP-X10 now, both of which offer several hundred movies available in a downloadable library. Both units require a Sony 4K TV, which is a major limitation. Sony has also released a small "Mastered in 4K" series on Blu-ray, which uses up the rest of the room on the disc for an improved picture, so there are no special features—but they're still 1080p discs and not 4K resolution.

As a rule, movie studios now routinely deliver 4K movies to commercial theaters, but none are available for home purchase yet in that format. A professional-grade camera like the Canon EOS C500 records 4K content, but at $26,000, it's not exactly a stocking stuffer. The GoPro Hero3 Black Edition$402.85 at Amazon puts 4K recording in your hands for just $400, though at 12 frames per second at that resolution, consider it a marketing gimmick more than anything else. More realistically, prosumer products like the $5,000 JVC GY-HMQ10 or the $4,500 Sony 4K HandyCam Camcorder FDR-AX1 record properly specified 4K video, but they're far from inexpensive. The $2,500 Sony Alpha 7SA$2,379.00 at DWI Digital Cameras does it as well, but only with an optional external recorder.

Bottom Line: Do You Need 4K?

Not yet, unless you're an early adopter with the cash to spend and plenty of patience. In which case, the answer is probably still not yet. Think of 4K as something mainstream consumers could be watching in the next several years. Early adopters and enthusiasts may be interested sooner, if the costs come down enough and there's enough content available.

It's already pretty clear 4K won't end up like the 3D fad in there not being enough good content available to watch, even years after the technology's debut. 4K has a much better chance of becoming mainstream, because it doesn't need special glasses, and because some movie studios are already defaulting to shooting in it and promising a broad base of available content down the line. Bottom line: For most of us, however tantalizing that 4K logo may seem, it's not a realistic proposition in the immediate future. It's something to keep an eye on further down the line.

Source : http://www.pcmag.com/

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