4K In Digital Signage: It’s Not A Sprint; It’s A Marathon

April 15, 2015 by Dave Haynes

4K television display

I have a business contact I work with on video production, and I mentioned to him recently how it may well be time to step up production from 720P to 1080P, as that now seems to have settled in as the standard in digital signage video outputs.

Nope, he said, we’re going right on past 1080P and doing 4K.

I suggested he might want to talk to the technical people first before leaping off that particular cliff.

4K video displays are gorgeous. The output is stunning. You need to get up reasonably close to appreciate it, but that quality and clarity is readily apparent.

But 4K files are also huge.


I knew this already, but it hit home one day recently when I started watching season 3 of House of Cards on Netflix, and I got a warning note from my broadband Internet carrier. I was almost maxing out my data cap for the month. Well, that’s weird, I thought, since I normally chew up maybe half that cap in a month, and we were away for 10 days!

Turns out there’s a setting in Netflix that auto-selects the best viewing experience, and it auto-selected me into watching House of Cards at something like 19 GBs an hour in glorious 4K. Watch a few hours like that, and there goes the data cap.

Problem is, I think my TV is 720P and that’s just fine because that’s all the cableco sends down anyway to my box. So I was getting 4K, but I wasn’t seeing 4K. Not even close.

By comparison, streaming that show on Netflix at 1080P equates to chewing about 5 GBs an hour. That’s the thing, right there, in terms that a knucklehead like me – with no engineering degree and no great fascination with video codecs – can latch on to and remember. 4K is four times the file size of 1080P. In technical terms, 4K resolution is 3840 pixels wide by 2160 pixels high. 1080P is 1920 by 1080. So 4K is twice as wide, and twice as high.

Yeah, so?

That means whatever transport method you are using to move files around a digital signage network will quadruple in traffic by going 4K. So whatever payload of new videos that took, I dunno, 15 minutes to distribute, will instead take an hour. What just required a small percentage of network capacity when it was 720P or 1080P video, will start eating much of the available bandwidth. Unless your software solution can throttle bandwidth consumption, and that setting is on and set right, moving a 4K file during store hours may mean you’re not also processing transactions at that same time.

If you are not sitting on a high capacity internal network, and instead paying a commercial provider for connectivity, the data cap you may have may no longer be workable when running 4K. You’ll need to up capacity and probably pay more.

If you are using Machine to Machine (M2M) wireless to move data around, 4K may well be one of those “Don’t even go there” situations because of the cost bump.

In other parts of the world, data caps are perhaps not a big issue, or an issue at all. But for now, in North America at least, getting to unlimited data comes at a BIG price.

Storage Pressures

Then there’s the storage issue. Do your players have sufficient on-board storage to load and keep MUCH bigger files? Does that little solid state player with the 16 GB drive have anywhere near enough capacity for 4X the data, for the same number of minutes of video?

And there’s the practical issue of whether the media players in the field can handle playing back CPU-intensive 4K video files.

There is a standard emerging, called h.265, that compresses video and will reduce that one hour of 4K down from 20 GBs to about 8 GB, which is MUCH better. But that requires a hardware video decoder on the play-out box, and in digital signage, there are some Brightsign boxes that do it right now, and a VIA Technologies box coming this fall. But that’s about it for that new standard, though there are some 4K boxes that use the older h.264. Right now, h.265 support is anything but common.

You cannot, as I understand it, just upgrade firmware on boxes in the field and turn them into h.265 players. It’s not that simple.

Not Much Content

And finally, there’s the issue of content – or more accurately the lack of it. Yes, Netflix and other streaming media companies are now producing original content in Ultra HD. But that has precious little relevance for digital signage networks.

Walking around Digital Signage Expo (was it a month ago already??), I saw lots of stock video running on 4K – scenics and nature shots. But that’s about it.

Search for content and you come up with lots of short clips of waves crashing on shorelines and butterflies amidst flowers. Lovely. But not all that relevant for the majority of sign networks out there.

To hammer the file size argument one more time – a photo-jpeg nature scene done in 4K is almost a GB in size, for 16 seconds.

For custom creative produced for very high-end retail and museums, hell yeah on 4K. You want maximum clarity when you are showing off a timepiece or other luxury goods. I’ve seen that sort of thing marketed at lower resolutions, and it shows. Badly.

However, for a sign network that’s going to be viewed at a substantial distance by most people, showing whatever you think is typical on a signage network, 4K is arguably way more than is needed or warranted. People aren’t close enough to appreciate all those pixels. And there’s no material ready to run at 4K because of the time, cost and horsepower needed to produce spots at that rez – when every other medium doesn’t need it.

If you are thinking 4K, or have clients thinking 4K, consider all the implications. You might end up with some beautiful monitors, and a bunch of new costs and headaches you don’t want or need. There may very well be a day when most panels out in the field are 4K, but I don’t think many network operators, owners or vendors need to be rushing to that.

That old adage probably applies here when it comes to any rush to 4K: It’s not a sprint. It’s a marathon.


What do you think?

  1. Dmitri says:

    Hi Dave, great article but no mention of vp9 or vp10 which solve the file size/adoption challenge.

  2. Bang on the money Dave, but you fail to mention one thing. Going 4K limits your content options downstream. If you choose to go 4K, your desktop resolution is going to be 4K. Rarely have I seen a pure video content strategy. Eventually, your advertisers / marketing people will demand some form of dynamic content (i.e HTML5 and or Flash). That’s when you’ll realize your fancy H.265 hardware decoder can’t help you decode a 60 fps HTML5 animation @ 3840 x 2160.

    I should mention that H.265 is massively parallel and lends itself well to multi-threaded CPU based decoding as well. But you need a beefy CPU.

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