4k UHD Players - I don't think I understand how UHD formats work with bitrate and color profiles

[Invanaar]

I'll start off by humbling myself and say: I thought I understood color profiles and bitrates and how they worked with UHD formats such as HDR10, HDR10+, Dolby Vision, and HLG, but I'm not so sure anymore.

 

So I recently got a 4k UHD tv (Hisense U9DG) which does support all 4 of the HD formats, as well as 4k 4:4:4. I also got a 4k UHD Blu ray player, the UBP-X800M2. I figured it was good enough to do what I wanted it to, but recently I noticed that it's not outputting at 4:4:4 color profile when I'm using Dolby Vision. It doesn't support HDR10+, but I do know I can get it to output 4k 4:4:4 when I'm using HDR10. So in tracking this down with Sony support they said that it doesn't support 4:4:4 at 4k 24Hz when Dolby Vision is on, only RGB color profile. Just out of curiosity, I also asked Panasonic if the DP-UB820-K supported 4k 24Hz 4:4:4 for Dolby Vision and they also said it didn't. They were also not clear about if HDR10+ supports 4:4:4 at 4k.

 

I guess I'm just confused, am I just completely misunderstanding how Dolby Vision works, or is current 4k UHD Blu-Ray player technology just limited? My understanding of 4:4:4 was that it basically meant there was no chroma subsampling. Does Dolby Vision just only support RGB color space and handles chroma subsampling another way? Is Chroma subsampling an inevitability of Dolby Vision?

 

I know Im talking about negligible differences, especially since I'm using a last gen tv at this point, but I just want to improve my understanding.

[tikker]

The spec doesn't seem to disallow it: https://professionalsupport.dolby.com/s/article/Dolby-Vision-4-0-Generic-Studio-Spec?language=en_US

That mentions RGB 4:4:4.

 

I know Reddit isn't exactly a reputable source, but perhaps it's just the device:

https://www.reddit.com/r/appletv/comments/s3y0ye/why_is_it_not_possible_to_set_chroma_444_with_4k/

Quote

Agreed that for anything other than gaming, anything over 4:2:0 chroma is redundant (video content is distributed as 4:2:0). But specifically, Dolby Vision is limited to 4:2:2 chroma to stay under the 18Gbps bandwidth limit of HDMI 2.0 (as is HDR10). You simply can’t pipe 8+ million pixels worth of 10-bit color 60 times per second without some subsampling.

 

As far as I know movies and stuff are done in 4:2:0 or 4:2:2 anyway, so if that is still correct then you are not missing much in the first place.

[Invanaar]

6 hours ago, tikker said:

The spec doesn't seem to disallow it: https://professionalsupport.dolby.com/s/article/Dolby-Vision-4-0-Generic-Studio-Spec?language=en_US

That mentions RGB 4:4:4.

 

I know Reddit isn't exactly a reputable source, but perhaps it's just the device:

https://www.reddit.com/r/appletv/comments/s3y0ye/why_is_it_not_possible_to_set_chroma_444_with_4k/

 

As far as I know movies and stuff are done in 4:2:0 or 4:2:2 anyway, so if that is still correct then you are not missing much in the first place.

Yea that's a good point, if movies aren't made in 4:4:4 it doesn't matter much I suppose lol

[dilpickle]

All video content you consume is 4:2:0. The only reason you need to go higher is for games/PC.