What’s the Difference between 4K and UHD?
If you’re confused by the different labels for the newer displays out there, you’re not alone (and this isn’t a new thing). Usually technology develops faster than the labels that apply to it, but, multiple competing technologies might have different names until the standards are set. If you remember the confusion of figuring out what was HD, Full-HD, and 1080p, you get how the confusion of standards works.
4K vs. UHD
In a technical sense, 4K is the standard developed by cinema to express a resolution of 4096 by 2160. Which works out to an aspect ratio (the comparison of the width to the height) of 1.9:1. Since most movies are shot in the 1.9:1 aspect ratio, the Cinema 4K resolution made perfect sense.
On the television side, Ultra-High Definition (UHD) was developed using the same number of horizontal lines of resolution as 4K (2160), but using the standard HDTV aspect ratio of 16:9 (or about 1.78:1). So the full resolution of a UHD display is 3840 by 2160 (or 256 pixels narrower than Cinema 4K).
4K plus UHD
Since the aspect ratios of cinema and television are staying unchanged, the difference between Cinema 4K and UHD is moot for most consumers. If you watch a 1.9:1 movie on a 16:9 screen you will either see black bars at the top and bottom of the screen or the playback hardware will chop off the extra pixels to fill the screen. In that sense there’s no difference between the experience of HD and 4K UHD media (though 4K is stunningly sharper and more clear than HD content).
While it does help to know the difference between Cinema 4K and UHD, in most cases it doesn’t matter much. Both 4K and UHD can be used interchangeably and they’re often used together. When you’re looking at 4K displays, they will almost always be of the UHD variety since they are exactly four-times the size of the previous standard 1080p displays (1920 by 1080).
In addition to the simple resolution of the display and the content, there are a few other standards that are necessary to make 4K work. The digital media, the physical media, and the connection between devices and the display all need to be up to the task of showing 4K content.
Digital video compression allows high resolution video files to be much smaller than the original making digital streaming and storage possible. The High Efficiency Video Coding standard (abbreviated by its numerical designation H.265) doubles the compression rate of the earlier standard (MPEG-4/H.264). The H.265 standard was approved in 2014 and published in early 2015.
For physical media, Blu-ray developed and published the standard for 4K UHD discs known as Ultra HD Blu-ray and announced it in May 2015 with the goal of having players and discs available by the end of the year.
For connecting devices to a 4K UHD display you can use either HDMI 2.0+ or DisplayPort 1.2+ if you’re connecting a computer. The higher standards for both connectors allow for better compression and bandwidth so that the display gets all of the information the device is sending it.
One of the key issues in the connection used is the number of frames per second displayed (measured in Hertz). The older HDMI 1.4 and DisplayPort 1.1 can send out video at 4K resolutions, but at only 30Hz while HDMI 2.0 and DisplayPort 1.2 support the much smoother 60Hz framerate (and when DisplayPort 1.3 launches this year it will support up to 8K resolution and full 4K 3D).
There’s always a learning curve when new technology comes out, but in this case things are fairly simple. Both 4K and UHD mean roughly the same thing (and are often used together). As long as you have the right connector and the right content your new Planar 4K display will look amazing.