Occasionally, defining a technical term for other people to understand is deceptively easy. In some cases, the thing you are being asked about can be described in a few sentences, and with a tiny bit of prior knowledge, can even be summed up with just one simple statement. The deception lies in that it isn't just the definition you have to supply, but the obligatory follow-up questions that force you to justify why it exists. Today's subject, 4K (as in TVs, monitors, video resolutions and so forth), fits neatly into this highly-annoying category.
The Pledge: what is 4K?
For most people, 4K or "
Ultra HD" is a "really high resolution" that, for most purposes, uses approximately four times the pixels of a typical HD (in this case, 1080p) image. This pretty much applies to the really expensive televisions seen in electronic retailers, and is touted as the next best thing for video. Just as with photographs, higher resolutions are better for seeing more detail in footage, potentially allowing viewers to see more than they would have via normal HD video. I won't blame you if you decide to skip down to the next subheading, if you want to just move on to the justification element.
Ignoring the various "standard definition" resolutions used around the world for normal television broadcasts, 1080p is classed as an image with a resolution of 1920x1080 pixels. Technically, 4K is covered by two different definitions, with the DCI 4K standard referring to a 4096x2160-resolution image, with a 1.9:1 aspect ratio, though this could be ignored for our purposes, as it's typically used in film and video production only.
Illustrating the difference in resolution sizes
The second and more common version is UHD-1, known to most people as Ultra HD in TV marketing materials, but also known as 2160p in some areas. Using a resolution of 3840x2160 with the same 16:9 aspect ratio as seen in HD, this works out to be four times the resolution of 1080p. Technically the Ultra HD name can also refer to 8K video, a resolution of 7680x4320, but outside some public demonstrations, it is a long way off from arriving in anyone's living room, and you may want to forget about it for now.
The Turn: a useful resolution that doesn't have 'that' much use
The follow-up question from people who have just been told what 4K is usually ends up being "can I use 4K now?" -- and while the answer is "yes," the problem is that it's followed by the word "but."
The key problem with having a 4K television is that you need to get hold of 4K content that will work with it. Sure, 4K televisions include upscaling features that can make a lower-resolution video seem to be closer to 4K via electronic voodoo, but you will only really see the effects if the source footage you are viewing is in 4K. Some TV producers provided early customers with a media server containing Ultra HD-resolution movies and videos to show off the extra pixels, but there are very few other avenues to acquire more content at this point.
Broadcasters are, for the most part, working on 4K
in the background, and content producers are shooting in 4K like mad -- without producing anything that the public can receive in that resolution presently. Most broadcast systems, including cable, satellite, and over-the-air channels, allocate a certain amount of bandwidth per channel, which -- thanks to advances in codecs -- helped increase the number of channels available to view.
Only a finite amount of bandwidth is available for all of these channels, and since 4K requires so much extra data in comparison to 1080p, broadcasters are steering clear of 4K broadcasts until bandwidth can be reduced further, or some of the lousier channels finally give up and surrender their bandwidth (which will never happen). An alternative to waiting for traditional broadcasters is to stream 4K content over the Internet.
Shows on Netflix, Amazon Prime Instant Video, and others, as well as some footage uploaded to YouTube, can be streamed via a home connection, though this too has its issues. Streaming 4K still requires a lot of bandwidth, with Netflix recommending a connection of at least 25Mbps, so people with slower connections will have to resort to downloading films from a small number of online stores. If certain ISPs continue their internet service data caps "trials," then 4K streaming will be dead in the water, unless the same companies find a way around the FCC.
You also have to be careful about whether your chosen hardware is actually capable of receiving 4K streams. For many major providers, they will allow streaming to a smart 4K TV, and though Netflix will allow a small number of streaming
set-top boxes to play 4K content, Amazon has largely restricted it to just its own
Fire TV devices, as well as the Roku 4.
This is all dependent on your having a video card or TV capable of displaying 4K, of course; otherwise, it just downscales to 1080p. Streaming through the current Apple TV is also a non-starter, as the set-top box doesn't support the resolution at all -- you may be starting to see why.
Lastly, there is always the possibility of getting a 4K-capable Blu-ray player, as there is a small-but-growing number of Blu-ray discs that offer 4K versions of movies. Aside from the extremely limited range, due to it being a relatively new market, the discs are also fairly expensive compared to their 1080p-based Blu-ray and DVD counterparts.
The Prestige: In certain cases, 4K is a great resolution
While 4K content consumption is available to some, there are alternative uses for 4K than trying to see the finer detail in explosions in YouTube videos. For a start, it gives you an extremely large desktop if you hook your Mac up to a 4K television or monitor.
According to Apple's
support pages, the late-2013 Mac Pro and iMac 27-inch (also the 4K 21.5-inch iMac), the late 2014 Mac mini, the Retina 12-inch MacBook, and the MacBook Air from early 2015, along with the late 2013 Retina MacBook Pro, all support 4K displays, as well as later models. In many cases, using HDMI will work, as well as DisplayPort, with some displays requiring a dual-cable setup.
In all cases, you end up with a very high-resolution desktop that you can fit apps side-by-side on, without resorting to using a second monitor. If you have the cash to spend, there's also the 27-inch iMac with a Retina 5K display, just in case you wanted to one-up anyone with a 4K TV (or the 4K 21.5-inch iMac, for that matter).
If you do go this route, this does give you another way of viewing content if your set-top boxes don't support 4K. Many streaming services can stream 4K to a computer fairly easily, and there's always the option of buying 4K movies online and downloading them for later viewing through this method, if the Internet connection isn't able to cope with streaming. Check with your provider about bandwidth limits, however.
Lastly, if you are an avid videographer or you record a lot of video clips for yourself, you really should consider filming in 4K. Recording in the higher resolution gives you a lot more elbow room when cropping a shot for a project you are eventually exporting at 1080p, and of course allows for releasing the project in 4K later when more people can appreciate it.
To sum up what 4K is, you're basically looking at a high-resolution video standard that's has four times the number of pixels as 1080p. It's a standard that has limited options for content consumption right now, but that could change in the coming years -- and it is extremely handy if you want to increase your available workspace for your computing setup. Depending on your social circle, having a 4K TV could be a way to make your friends jealous, even if all you do with it is watch Kevin Spacey's forehead for wrinkles.
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