The real advantage of 8K resolution right now is in acquisition. Movies and TV programs can be filmed in 8K and down-converted to 4K and Full HD for distribution, and in fact will look to have more detail than programs captured in native 4K. But the 4x multiplier in both image pixels and file sizes is a challenge to manage for 8K production: Consider that a single 8K video frame has 33 million pixels compared to the 8.8 million pixels contained in a 4K video frame, and you’ll see the problems in moving those pixels at a 60 Hz frame rate.
The differences between televisions and display monitors are insignificant these days, mostly found in the number and types of interfaces and the design of power supplies, mounts, and bezels. The AV industry started moving to 4K displays a few years ago as production of FHD models was declining. Signal switching and distribution for these products isn’t that much of a challenge, given the preponderance of HDMI 2.0 and DisplayPort 1.2 interfaces and signal management products that support them.
It’s not quite that simple with 8K. Refreshing an 8K/60 display signal at 60 Hz – one with 8-bit RGB color – requires a signal highway that can support at least 72 gigabits per second (Gb/s) sustained rates. That’s four HDMI 2.0 connections running simultaneously! And, although we’re seeing increased support for the faster HDMI 2.1 standard in the CE world, it’s going to have a much slower path to adoption in commercial AV applications…and it’s still not fast enough for the 8K/60 4:4:4 example just cited.
Given that proponents of 8K video have permanently linked high dynamic range to the format, it’s almost pointless to try and calculate an 8K signal variant that we can stuff through an HDMI 2.0 port. (For those playing at home, 8K/24 and 8K/30 with 8-bit 4:2:0 color will make it under the bar at 17.82 Gb/s, and that’s it. No support for HDR, though.) To achieve 8K resolution, it’s a far simpler task to tile and interface four 4K-resolution displays.
As far as moving 8K video through an IT network switch goes; it can be done using a mezzanine-level codec like JPEG XS and has been successfully demonstrated by the Japanese TV network NHK. Using 5:1 JPEG-XS compression, an 8K/60 10-bit 4:2:2 video signal cruises through a 10Gig switch @ 9.5 Gb/s. However, we still need to convert it to a display format at the final connection, once again using multiple HDMI or DisplayPort interfaces.
Summing up; it’s going to be a while yet before our industry will consider 8K video and display an ‘everyday’ product, one that warrants much of our energy and money to support. And 8K will remain a more exotic format for some time, due to a combination of financial and technical limitations. For now, 4K is established, affordable, and far less complex to switch and distribute in an AV system.
But check back next year…you never know…