Why is does Apple TV 4th Gen not support HDR in 4:4:4 or RGB

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Level 1

8 points

Why is does Apple TV 4th Gen not support HDR in 4:4:4 or RGB

I have a HDMI 2.1 cable and a high end laser Sony projector; both of which when connected to my Panasonic DP-UB9000 player, will show 4k UHD content at 4:4:4 or RGB Enhanced at 50/60Hz frames, in HDR with BT.2020. So I know my system end-to-end is capable of showing high end HDR 4k content like this.

However, when i replace the Panasonic Blu-ray for an Apple TV - leaving everything else the same - the only option I see in the Apple TV is i can use SDR at 4:4:4 and/or RGB high - I choose RGB high - but when I switch to HDR on the Apple TV, I'm limited to 4:2:2 (or the lower 4:2:0) and there is no longer any RGB option at all.

I have no option to choose RGB, or indeed 4:4:4 - as I could on the Blu-Ray Player.

I'm presuming since the Panasonic Blu Ray player can do 4k HDR at RGB or 4:4:4 that the limitation is not my system, cables or the HDMI spec, but instead some limitation in the Apple TV 4th Gen Hardware, but would appreciate comments from others on this, on what is limiting this on the Apple TV Platform?

Thanks,

Nick

Posted on Sep 19, 2020 2:33 PM

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Answer 1

Urquhart1244

Level 10

146,520 points

Sep 19, 2020 3:33 PM in response to nick-london

Apple TV (4th generation) can’t do HDR.

Apple TV 4K (5th generation) can do HDR, but within the bandwidth limits of HDMI 2.0.

Being limited to 4:2:0 is not an issue, as ANY streaming video is 4:2:0 already. You can’t get that chroma detailing back by using twice as much bits.

Any streaming video is YCbCr already. There is no need to convert in the Apple TV box to RGB, when your TV can do that just as well.

The Panasonic DP-UB9000 has a HDMI 2.0 port as well, meaning it can do 4K HDR @60 fps, but not at 4:4:4 at the same time. It can do 4K HDR 4:4:4, but not at @60 fps at the same time. The trade-off is that all these settings to the max will exceed the HDMI 2.0 specification of the ports. A HDMI 2.1 cable doesn’t change that.

This isn’t an issue, as most content will be 24 fps or 30 fps, not 60 fps.

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Answer 2

nick-london Author

Level 1

8 points

Sep 19, 2020 4:02 PM in response to Urquhart1244

Sorry my bad, I meant 5th Gen...it was a typo.

I have frame match on so most of my streaming Apple TV comes in 24p, yet I still can't get higher than 4:2:0 and don't get that option for RGB, which I understood was purer than 4:2:0.

But are you stating that whilst UHD 4k disks may have higher detail, that the streaming codecs are limited in their compression as a tradeoff for streaming so it doesn't make sense to have anything higher?

Thanks for helping me understand better.

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Why is does Apple TV 4th Gen not support HDR in 4:4:4 or RGB

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