Why 4K Isn’t Yet Ready For Digital Signage Prime Time

June 21, 2014 by guest author Tara Parachuk, Tara Parachuk

4K television display

Guest Post: Manuel Edghill, digbil

Much buzz has been generated in the digital signage industry surrounding 4K displays and content. A lot of this hype is generated by 4K display manufacturers. But is 4K truly ready to become mainstream in digital signage?

Most potential consumers of 4K displays who have viewed them in person have typically done so at a trade show or in an electronics store. Why is this significant? In such controlled environments 4K manufacturers and retailers present displays that come across as visually stunning. However, these contexts take advantage of the fact that:

The relationship between resolution and viewing distance

In many out of home digital signage applications the screen is simply too far away from the viewer for the added resolution of 4K to be noticeable.

The higher the resolution, the larger the screen must be and the closer the viewing distance for people to be able to notice the difference. Gadget columnist Alice Truong states that as a rule of thumb, differences in resolution become noticeable if a person is at a distance of 1.5 times the screen height or closer.

As opposed to the typical viewing distance associated with the average mobile device or laptop, digital signs are not usually just a few inches away from the viewer.

Using digital menu boards as an example, if the display size is 42 inches then customers need to be within a viewing distance of 5.25 feet to differentiate between the resolution of 1080p and 4K. Customers standing in line to order at a quick service restaurant may be close enough to notice the enhanced quality, but for anyone else the added resolution has little to no benefit.

In contrast, take an example from the average home living room where TV viewers typically sit as close as six feet from the screen. At that distance, a 100-inch 4K image will appear sharp.

The chart below, courtesy of tech blogger Carlton Bale, combines viewing distance (in feet) with diagonal screen size (in inches). The chart depicts how close you need to be to the screen in order to detect some or all of the benefits of a higher resolution screen at any given screen size.

viewingChart4K

As the data suggests, in order to maximize ROI on 4K digital signs the viewing distance needs to be less than 5 feet.

Digital signs require continuous fresh content to attract attention: an expensive proposition with today’s 4K technology

Even if a company’s digital signage use case can make do with the limits of viewing distance discussed above, consider the in-house resources required to develop and maintain 4K content.

“For companies that want to create seasonal content that will change every few months, the cost of producing content in 4K is a lot higher than in HD,” said Steve Scorse, Vice President of EMEA at SiliconCore Technology.

While technology costs are decreasing and efficiency continues to increase, resource constraints still remain. 4K video files are four times the size of 1080p files, requiring additional bandwidth to transfer and four times more storage space.

In addition, providing viewers with a relatively seamless viewing experience (lack of pauses, pixelation and “blocky” images) may require an “upgrade [to] your network and other wiring,” according to Tom Barnett, Residential Marketing Director of Creston.

For example, this type of viewing experience requires at a minimum the ability to display 4K content at 60 frames per second (fps). The display hardware needs a video card that supports this, as well as HDMI 2.0 output (HDMI 1.4, still largely in use, will support the display of 4K at 30 fps, which will cause 4K video to “jump”). Noteworthy is the fact that not all 4K displays on the market support these requirements.

Resources required for 4K content production are still maturing, expensive and aimed primarily at the broadcast market

As is the case with requirements for 4K display, content production for the new resolution will most likely translate into the need for equipment upgrades. According to John Morris, Senior Editor at PC Magazine, “… four times the resolution means lots more information needs to be captured, transferred and stored, produced and distributed. That requires new cameras and production equipment, better compression…”

Hardware vendors are just starting to make 4K production equipment available, much of which is geared specifically towards content creators in the broadcasting market. Last month Ars Technica published their review of Toshiba’s self-proclaimed “world’s first 4K laptop.” During their assessment they edited two MP4 videos that had been recorded in 4K (3840 x 2160). Their experience ended with one video displaying at 30 fps, whereas the latter ran at 15 fps (due to the camera used). The computer had an HDMI 1.4 output.

At the end of the day, there’s not much point to a 4K screen if it does not have the appropriate content to accompany it. As stated by Jade Li, Advantech Digital Signage Product Manager: “End-to-end content generation and distribution workflows are only emerging in the broadcast market and are not a reality yet in digital signage.”

Until then, 4K will have to wait.

Conclusion

Given all of the above, it stands to reason that the majority of 4K content in the near future will continue to be produced by big businesses and events who can afford to experiment – such as major sporting events like the World Cup this year.

It boils down to whether or not it makes sense for a business to make an investment in technology that may be significantly more expensive than the current standard. In addition, 4K content will not be easy to come by in the near future, and 4K displays will only provide a slight improvement in image quality.

No doubt the buzz and momentum around 4K will continue. It may well gain a foothold in the consumer electronic market. However, it currently faces obstacles such as the requirements regarding screen size, viewing distance and the human ability to discern different resolutions. In addition, there are clear limitations and investments required for otherwise potential 4K content creators that will not optimize returns. Therefore, the current industry standard of 1080p is the rational choice for digital signage at this point in time.

  1. Johnathan says:

    I agree. 4K displays are not prepared for broadcasting. It is worse than having a 4-times-retina display on a phone: you will not see the difference but the hardware must be 4 times powerful to handle it. As I can see, right now 4K displays have a place on showing/producing technical or professional applications where the user(viewer) is really close to the display, not for TV broadcasts or streaming.
    In graphic design you can print at lower resolutions and also very high resolutions. You print at 1200dpi a picture that will be really close to the viewer, but a big sign of 30 x 60 meters that will be on the side of the highway, on top a building, you don’t print it at 1200dpi, nor 300dpi, you use 36dpi because there is not a viewing difference at that distance/size. Of course you can print it at 1200dpi but it will cost you significant more, and will have the same result.

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