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Going Beyond 4K

Guest Blogger: Kramer Electronics

While our industry is scrambling to keep up with the emergence of 4K and Ultra HD displays, there’s an even bigger tidal wave headed our way.

Let us explain. The rapid expansion of display panel manufacturing in Korea, Taiwan, and China has at times led to overcapacity – too many ‘fabs’ pushing out big sheets of display ‘mother glass’ that can then be cut up into much smaller pieces for everything from smart phones to televisions.

There was another side effect of the expansion. Chinese panel manufacturers such as TCL and BOE determined that they could make individual display panels with Ultra HD resolution (3840x2160 pixels) for about the same cost as Full HD panels (1920x1080 and 1920x1200).

Not only that, they started experimenting with even higher pixel counts. Among the products that emerged from those tests were panels with 8K resolution (7680x4320 pixels) in sizes as small as 65 inches and as large as 98 inches. Another offshoot was super widescreen televisions with a pixel count of 5120 horizontally and 2160 vertically, producing an aspect ratio closer to the old CinemaScope format developed in the 1950s.

Okay, so we really can’t buy any of these products today – at least, not readily, and not without pulling some high-level strings. Their day will come yet. But there is another product that emerged from all of this fab experimentation – one we can pick up for about two grand.

And that’s a 27-inch widescreen monitor that comes from the LG Display fab in Paju, Korea. It’s sold by LG and several other companies, one of the latter being those guys that use a piece of fruit as their logo. The size of the monitor is one thing, but the pixel resolution is something else: 5120x2880 pixels, or ‘5K’ resolution.

Holy cow! You’re thinking. We’re barely getting a handle on 4K, and there’s already a 5K monitor for sale? Yes, Virginia and it’s not particularly easy to interface. Leaving the video graphics card requirements aside for a moment, we now have a display that at the bare minimum needs signals with a clock rate in excess of 1 GHz with a refresh rate of 60 Hz!

You betcha that signal won’t make it through an HDMI port, and a single DisplayPort interface isn’t up to the heavy lifting, either. We’re somewhere in the 32 Gb/s range as a data rate requirement if we’re going to plug in a 5K/60 signal with 10-bit color, depending on the blanking interval size. And that will take at least two interfaces to pull off, with each sharing half the image data.

Sounds nutty, but it’s not the first time manufacturers had to do this. The first 4K display monitors to wash up on our shores in 2012 were all variants of an 84-inch Ultra HD LCD panel also made by LG Display. Each one of them required four (that’s right, FOUR) HDMI 1.3/1.4 inputs to drive the display. Each input handled ¼ of the image, or a 1920x1080 segment. Talk about a wiring nightmare!

As it turns out, the LG/Dell/Apple/Philips 5K display is equipped with multiple USB Type-C connections and zero display interfaces. That’s because the Type-C connector can double as a display interface when operating in DisplayPort Alternate Mode. The question is; which version of DisplayPort?

Version 1.2 isn’t good for anything faster than 21.6 Gb’s, but version 1.3 and 1.4 can hit 32.4 Gb/s. That’s probably just fast enough to make a single connection for our 5K/60 10-bit RGB video. But DisplayPort 1.3 and 1.4 can also drive two displays simultaneously, so how’s about we set our video card to output a pair of 2560x2880 signals and just stitch them together  in the monitor?

If this approach sounds nutty to you (it does work, by the way), imagine how it sounds to manufacturers of signal management equipment. Will there be a call from a dealer asking for a four- or eight-port distribution amplifier that can handle a 5K signal? Maybe what’s needed is a two-input DA with 8 or 16 outputs, since we need two connections for each display?

Or maybe we’re better off with a matrix switch, assigning two inputs to sets of dual outputs. Of course, we have to be very careful to make sure the right inputs are switched to the right outputs – otherwise we’ll have some very strange-looking images on the screen.

This is not hypothetical stuff. These 5K monitors can be bought right now on Amazon and in any Apple store. There are customers who will want to create and view images at 5K resolution for whatever reason. And it’s likely that some  of them may want to view those images on multiple monitors at the same time, hence the need for a DA or switch.

So what’s to stop display manufacturers at 5K? well, nothing. We’ve seen prototypes of displays with 6K resolution, and of course there are those 8K behemoths lurking out there. Dell is already selling an 8K premium monitor for high-end workstations. The UltraSharp UP3218K is a 32-inch design that will set you back a cool $4,999, and it comes with a pair of DisplayPort inputs (that image stitching thing again).

The morale of our story? Don’t get too comfortable with 4K. We’re just getting started…