What is 4K Ultra High Definition TV?

Learn about the new technology that provides four times the resolution of a typical HDTV

By

Steve Kindig

Steve Kindig has been an electronics enthusiast for over 30 years. He has written extensively about home and car A/V gear for Crutchfield since 1985. Steve is also a volunteer DJ at community radio station WTJU, where he is a regular host of the American folk show "Atlantic Weekly," as well as the world music program "Radio Tropicale."

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Samsung 55HU8550

Ultra High Definition TVs have started a high-resolution revolution. These Ultra HD TVs have four times the picture resolution of regular “full HD" 1080p TVs, and can display much more detail. Ultra HD TVs are often referred to as “4K" TVs, because they have a horizontal resolution of around 4000 pixels.

You've probably seen a movie in 4K without even realizing it — 40% of movie theaters use 4K digital projectors to display Hollywood’s latest hits with maximum detail and depth. Now, imagine how lifelike watching at home would be with that many pixels on a 55", 65", or 85" screen instead of a 30-foot theater screen. That's the reality of 4K Ultra High Definition TV.

More pixels = more picture detail

Whether it's a TV, a tablet, or a smartphone, the more pixels a screen has, the more seamless and detailed the picture will look. The ideal is a screen where the "pixel structure" is invisible. You already find that on high-end tablets and phones like those with Apple's "Retina" display. 4K Ultra High Definition models take television a giant step in that direction — you have to stand right next to an Ultra HD TV to notice any pixels at all. Because the picture is so clear and sharp, you can actually sit closer to a 4K TV even if the screen is larger than your old TV. And that adds even more to the sense of immersion.

4K picture resolution vs. 1080p

4K Ultra HD TVs have four times as many pixels as a 1080p HDTV, for a picture that's incredibly clear, detailed, and lifelike.


How close should you sit to a 4K TV? Most experts say you can get as close as 1-1/2 times the screen height, versus 3 times the screen height for a 1080p TV. That's much closer than most of us sit when watching HDTV, but it really transforms the experience — the screen completely fills your field of vision, making you feel more like you’re in the scene. A darkened room and surround sound will further intensify this feeling of immersion.

How much 4K content is available?

Sony FMP-X10

Sony's FMP-X10 4K Ultra HD media player.

4K TVs have quickly become popular, but there's still a limited amount of true 4K content to watch. The same thing happened with the introduction of DVD, HDTV, and Blu-ray — the hardware arrived first, followed by the content. Sony offers an Ultra HD media player, the FMP-X10, that lets you download titles from Sony's online library of 4K films, for rental or purchase. The FMP-X10 also has the ability to play streamed 4K content from Netflix®, making it especially valuable to owners of 2013 Sony 4K TVs, which lacked that capability.

Samsung UHD Video Pack

Samsung's 4K Ultra HD media player.

Samsung also makes a 4K media player, called the UHD Video Pack. If you own one of Samsung's 2014 4K Ultra HD TVs, this is a great accessory. It's a 1-terabyte hard drive that comes pre-loaded with several full-length movies and nature documentaries, all in full 4K resolution. Once you plug it into the TV's USB input, the player's menu appears on the TV screen, and you can navigate and make selections using the TV remote.

Netflix launched their 4K streaming service last year with their original series House of Cards. They've since beefed up their 4K offerings with the complete Breaking Bad series, The Blacklist, as well as their home-grown Marco Polo series. To watch Netflix in 4K, viewers will need a 2014 or newer Ultra HD TV with HEVC decoding, a Netflix 4K streaming subscription (currently $12.99/mo.), and reasonably fast Internet service — at least 20Mbps. Amazon joined the 4K club with their streaming service that, initially anyway, is only available — for free! — to Amazon Prime members.

Two more 4K video sources launched at the tail end of 2014. DirecTV's 4K Ultra HD service offers a limited selection of 4K movies available on a pay-per-view basis. In order to use the service, you must not only be a DirecTV subscriber, but must also have DirecTV's Genie whole house HD DVR, along with a DirecTV-ready Ultra HD TV, such as Samsung's Ultra HD models. And Comcast announced their Xfinity in UHD, which is also an on-demand service that initially only works with Samsung 4K TVs.

YouTube has an eclectic and growing library of millions of 4K video clips. While you probably won't find your favorite movie or TV show, there is plenty of 4K eye candy, including some wonderful nature documentary footage. In the meantime, if you have a camera with at least 8-megapixel resolution, then you have a source for 4K photos.

Sony's 4K X-reality Pro upconversion

How will my current video sources look on a 4K TV?

Don't worry if you don't have access to any 4K video sources right away. All 4K TVs include built-in 4K upconversion, also called "upscaling," which takes the video signals from your Blu-ray player, satellite or cable TV box, or game console, and makes them fill the 4-times greater pixel count of the 4K screen. Without upconversion, a 1080p Blu-ray signal would appear as a small rectangular image at the center of the screen, with black bars on all sides. While upconverted 4K isn't the same as true 4K, the processing enhances the appearance of non-4K video to more closely resemble 4K.

Why are there so few 4K TVs in smaller screen sizes?

Although 4K TV screen sizes now extend down to 40", most people find that 1080p resolution looks "good enough" on screens 50" or less. From a typical viewing distance you won't notice the screen's grid of pixels — sometimes called the “pixel structure." But 55" and larger screens benefit from a much higher pixel count, making the grid virtually invisible. Ultra HD not only offers a more detailed picture, but also allows you to sit closer to a screen and/or view a larger screen while enjoying unprecedented clarity.

Sony 4K Ultra High Definition TVs

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Sony XBR-55X850B

Sony has more 4K experience than any other TV maker. They build professional 4K cameras and cinema projectors, and Sony Pictures has a bigger catalog of 4K films than any other studio. This end-to-end approach helps ensure a truly theater-like experience at home.

Samsung 4K Ultra High Definition TVs

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Samsung UN55HU9000

Samsung's top-of-the-line curved-screen JS9500 series TVs offer exceptional picture quality and future-readiness. Each TV includes a separate One Connect Box with inputs for your video components. In the future you'll be able to get a newer-version Box that will upgrade the TV's main processor, graphics processor, and memory to support future formats as they evolve.

LG 4K Ultra High Definition TVs

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LG 55UB8500

LG's UF7700 series models are among the most affordable 2015 Ultra HD TVs we've seen from a top-tier brand. LG's IPS panel technology keeps picture contrast and color looking crisp even as you move from directly in front of the screen to viewing more from the sides.

Sharp 4K Ultra High Definition TVs

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Sharp LC-60UD27U

Sharp's 70" LC-70UH30U is among the very few TVs that have earned THX® 4K certification. Getting THX certified has never been easy, but to be 4K-certified, this TV had to pass over 400 rigorous laboratory tests — for both HD and 4K picture quality.

The era of 4K Ultra High Definition TV is up and running. Stay tuned for further developments.