Ultra High Definition - High Dynamic Range TV 04Feb20

As I investigate the latest in TV like 4K, 8K, UHD, HDR, etc. I drilled on where content comes from, who delivers it,  what the implications of it are on infrastructure and how human perception deals with it. As to content and who delivers it...

1. Broadcasters and mainstream OTA channels (ABC, CBS, NBC, FOX, CW, PBS, etc.) won't be doing anything anytime soon. OTA digital will get you 1080p (1K), and Rec 709 color gamut (8 bit), at best, for some time to come. While some initial camerawork is done in 4K, transmission mostly is not. The cost to upgrade the whole camera, recordings, decoding, & transmission systems is daunting.
2. Very few satellite or cable channels offer 4K content, but there is some stuff there. 
3. DVDs are 480p, Blu-Rays are 1080p and you need to get up to Ultra Blu-Ray to get more. Mostly I sense folks say "who cares" and don't buy a new disc player with each new iteration, just so they can buy a few expensive new discs. When I went to Blu-Ray I did so 'cause an old player died and I own like two discs.
4. The content is coming mostly from none other than Netflix (and the other over the top content builders and streamers, like AMZ Prime, Hulu, etc.). You need to upgrade your Netflix service to premium ($17/mo vs $12/mo) to access the 100 or so titles available in UHD, but they keep making more.

So other than premium over the top services and a new 4K TV, what do you need to partake? Really just sufficient bandwidth on your internet connection (and WiFi if that's your final leg to the tube). Netflix recommends steady 25Mbps but that's probably overkill... others require less. I wanted the very specific calculation of pixels on screen, of certain color depth, at a certain refresh rate to Gbps broadband needed.

First I needed to understand UHD and HDR characteristics. There are three primary vectors on which UHD-HDR TV advances from HDTV: resolution, color depth and dynamic range. Resolution refers to the number of pixels on the screen, color depth refers to the number of colors that can be displayed by a given pixel, dynamic range refers to basically brightness - how black is black and how white is white.

• Pixel resolution of UHDTV is 4X that of HDTV (1096x732) at a minimum of 3840×2160 and potentially 4400x2250 (where some pixels are likely inactive), or even twice that again for 8K TV

• Color gamut of 4K TV (the standard is called Rec 2020 and is represented in at least 10 bit depth) is 1.9X the size of HDTV. It is getting closer to the human eye's ability to process colors (shown as the full colored shape in the graph above). HDR10+ is announced for 8K TV and requires 12 bit color depth. TVs with these larger color gamuts are often said to have Wide Color Gamut or WCG.

 

• Dynamic range is a ratio between the smallest and largest of something; in this case, levels of brightness or luminance values presentable on a TV display. The numerator and denominator are best measured in nits (amount of light output equal to one candela per square meter, cd/m2 - a standardized measurement of luminous intensity). Visually there is a big difference looming here - brightness and contrast count - much darker blacks and much lighter whites. Standard dynamic range (SDR) TVs have a dynamic range of about 6 f-stops (200-300) and HDR TVs have a range of 11 f-stops (~1000) and Sony has demoed even much greater. Remember, every f-stop gives you 2X the prior so HDR TVs delivery 10X the luminous intensity range of SRD TVs. Cameras have long been able to capture and record with very high dynamic range, like 14 f-stops but our displays are only now coming close to delivering that for viewing. If you've ever experienced the dark scenes on your TV, where you can't really see what's going on - these will get much better on newer HDR sets and content. Recognize too here that good high speed HDMI cabling will be needed.

These differences MAY add up to huge visual impressions for us, and elicit wicked visceral responses, but when and where can we really perceive them? HDTV was studied extensively when being readied for launch and we know human visual acuity can delineate 1 arc-minute. This led Lachtey to devise guidelines for how close one should sit to a 1080p HDTV panel for immersive viewing. Our eyes have 135° of angular range, mixed viewing suggests we sit to cover 30° of viewing and THX (cinema standards) suggested 40°. So I set up my 77" diagonal UHD/HDR TV seating at 8'-10' and it was perfect. Given human visual acuity I can now move seating in 50% to 4'-5' for the best experience. Wow! This will mess with my acoustical sweet spot too. Staying at 8' would just mean I didn't need to get a 4K panel (ignoring brightness for a bit).

All fine, here is the bandwidth calculation, approximately: 4400 horiz X 2250 vert X 60 Hz refresh means 594M pix/sec need updating! Chroma sampling at 4:2:0 yields ~11Mbps (but some suggest 7.2Mbps is sufficient). In any event, I have this all covered in my $35/mo 15Mbps downstream feed - and the content at these target levels won't really be here for a while.