Originally Posted by Lammiwinks
Anyone else getting banding on HDR 4:2:2? I have a HU9000 and a SEK3500 and when selecting 4:2:2 @ 60hz I get banding in the icons. Wondering if the Apple TV is not outputting @ 10 bits on 4:2:2? All seems fine when on 4:2:0. Using a Belkin High Speed HDMI cable from the Apple Store.
Also finding some strange film grain effects happening - I'm experimenting with my settings to see what's causing it (could just be the extra fidelity!).
I have a UN65JS9500 and Roku Ultra.
HDR also has banding on 4:2:2 and clears up with 4:2:0 I've seen this on Amazon 4K Video. To date, Roku has only used 60 fps in OS 7 and below, AFAIK
There are TVs that can handle 4:2:2 HDR 60 fps but Samsung doesn't seem to be one of them. Not in 2015, it seems.
Not sure but I think the theory has been 4:2:2 is 12 bit and 4:2:0 is 10 bit but it may be how it's traditionally been transmitted rather than panel bit-- see the quote with linked article and paragraph I included below).
Maybe someone has more insight on that? But I found this post interesting in the Roku Premiere+ and Roku Ultra owner's thread:
Particularly, this paragraph in the linked article:
"Historically the source upsamples to 4:2:2, which is sent over HDMI, and then the display upsamples to 4:4:4 and converts to RGB. The reason for this sequence is that HDMI v1.4 and previous iterations did not support 4:2:0. HDMI2.0 does support 4:2:0 though only at 50/60 frames per second (FPS). At 24 FPS 10 bit only 4:4:4 and RGB are supported."
Suggests HDR 24 fps should be up sampled to 4:4:4(??) by source to TV input and HDR 60 fps should be up sampled to 4:2:0 (bandwidth and recent HDMI standards have played a role here, it seems). Perhaps that's a theory you can test with your Apple TV 4K?
Apparently, native 24, 25 and 30 fps added to Roku OS 8 for HDR devices works well.
Interesting to know that Apple and Roku are very similar on chroma results (4:2:2 60 fps source setting for HDR causes banding for us). Does 4:2:2 or 4:4:4 24 fps source setting for HDR cause banding too? The article seems to suggest the source would have to use chroma up sampling to 4:4:4 for 24 fps HDR? If so, I'd think Roku and Apple know this.
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