Three-Minute Tech: 4K resolution

[In our Three-Minute Tech series, we tell you everything you really need to know about a technology in three minutes or less.]

Standard video resolutions (scaled to 16:9) showing relative sizes.

Think you’re seeing it all? Not when it comes to digital video. The resolution of current digital video offerings still falls short of what 35mm film offers.

To get closer to film quality, we have to pack in more pixels. High-definition as we know it is no longer good enough–get ready for 4K resolution.

The numbers

Increased resolution in digital video increases the sharpness of the image. The current high-end standard in television is 1920 x 1080 pixels—also known as 1080p.

4K resolution roughly quadruples the number of pixels found in current HDTVs. The 4K part comes from the width of the picture: approximately 4000 pixels. Note that with 4K video, the term switches to using width instead of vertical pixels (with 1080p, the "1080" refers to the vertical number of pixels, 4K refers to the horizontal). 4K video has about 2000 pixels vertically.

I say "about" because the 4K standards are still developing. One standard maintains the 16:9 aspect ratio of HDTVs at 3840 x 2160 pixels, and is also called Quad Full High Definition (QFHD) or 2160p; another expands the width to 4096 x 2160 and is aimed at the cinema. Either way, you're looking at more than 8 million pixels, while a 1080p TV has about 2 million.

Cinema-tech

4K resolution exists today, and you may have already experienced it at the movie theater. Recent films such as The Amazing Spider-Man and Prometheus were shot using cameras capable of 4K resolution, so if you saw a digital projection in the theater, you may have seen 4K digital video.

The Amazing Spider-Man was shot in 4K resolution.
Jaimie Trueblood (Columbia Pictures Industries, Inc)

Standard HD resolution looks pretty sharp in your living room, but that same sharpness looks blocky and pixelated when blown up to a 40-foot screen. The 4K standard takes care of that problem. If you're sitting in the back of a theater with a smaller movie screen, you may not notice any difference in sharpness.

Coming to a home theater near you

While you may have experienced 4K in the theater, you’ll find a real lack of displays or content for the home.

The only 4K video I could find to watch at home is TimeScapes, a documentary. It is available on a USB stick for $100. When 4K videos do become widely available, many industry analysts believe that the content will be delivered over the internet, though four-layer Blu-ray discs are being developed with enough storage to hold a 4K movie.

Bandwidth could be a major obstacle in getting 4K video, since most of us don’t have the massive bandwidth needed to stream the files smoothly. 4K files will be hefty in size: as an example, the 4K version digital version of TimeScapes, which runs 52 minutes, weighs in at 25GB.

Even if you have a 4K video file, you need a device capable of displaying the resolution to get the benefit of all those pixels. Those are scarce right now, too. LG, Toshiba, and other major display companies expect to have devices available later in 2012 and 2013, but get ready for sticker shock. One of the few currently available display devices, Sony’s VPL-VW1000ES SXRD 4K projector, comes with a hefty $25,000 price tag.

Sony's drool-worthy VPL-VW1000ES 4K projector comes with a hefty $25,000 price tag.

The home theater industry is ready whenever 4K displays arrive, however. New audio-video receivers and Blu-ray players offer “4K upscaling” that enhances high-definition sources to take advantage of these displays' extra pixels. This isn't true 4K, but upscaling might make the picture sharper on a 4K monitor than an unmodified HD source. The latest HDMI standard, 1.4a, is also ready for 4K and will pass through 4K signals, once all the necessary devices arrive.

Is 4K worth the hype?

The big question is, will you even notice the extra resolution? In most cases, probably not. You only really notice the difference between 720p and 1080p on an 42-inch HDTV if you are no more than six feet from it. With 4K, you’ll need to be even closer than 6 feet with a TV over 55 inches. Anything smaller, or further, and your eyes can't see the pixels on 1080p, so all that extra resolution essentially goes to waste.

And, before you invest too heavily in 4K, realize that there are more pixels on the horizon. Peter Jackson filmed The Hobbit, due out in December 2012, in 5K resolution, and 8K is on the way. It's possible that 4K is a essentially resting point along the way to even more resolution.

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