3 ms·

HDMI 2.0 is capable of doing 4k @ 120Hz, but only up to YCbCr 4:2:0 8bit instead of the full YCbCr 4:4:4 10bit (though I'm not sure how close wayland is to 10bi

HDMI 2.0 is capable of doing 4k @ 120Hz, but only up to YCbCr 4:2:0 8bit instead of the full YCbCr 4:4:4 10bit (though I'm not sure how close wayland is to 10bit support). It will be fine for gaming, just not for everyday PC use. FWIW I also didn't realise this until just now. I've been running my desktop at 4k@120hz recently for the buttery smooth neovide, but have been noticing that text rendering, especially syntax-highlighted text, looks awful. I'd seen the same oled panel render text way better in WSL/Windows (both using a custom pixel geometry[0] via Mactype, but also without), so I spent more time than I'm willing to admit to wrapping my head around custom pixel layouts and hinting in freetype. But no, turns out it was this all along. If you want to see the effect of 420 vs 444 chroma subsampling on text rendering, this writeup[1] has some great test images and is well worth a read. Also, if you happen to have an LG OLED panel, you can get a little debug window that confirms your signal format and refresh rate, by pressing the green button on the remote 7-8 times. [0]: https://github.com/snowie2000/mactype/issues/720 https://github.com/snowie2000/mactype/issues/720 [1]: https://www.rtings.com/tv/learn/chroma-subsampling https://www.rtings.com/tv/learn/chroma-subsampling

_kb 3y ago
Another immensely useful source and pattern generator is also https://www.extron.com/article/testpattern https://www.extron.com/article/testpattern.
Cu3PO42 3y ago
I once had a bad cable, which forced a 4k@60 monitor into chroma subsampling. Or rather Windows decided it would rather enable Chroma subsampling than drop resolution or framerate. I immediately noticed there was something wrong. I agree it's terrible for desktop use. I would probably also have blamed freetype if it only happened on Linux, though.
account42 3y ago
> It will be fine for gaming I disagree. Gaming can involve lots of (colored) text too. And besides, if you have invested in a 4k@120Hz monitor are you really going to accept chroma subsampling even for non-text content? I hate how the connection just magically switches to chroma subsampling (and/or DSC with newer connection standards) instead of that being something you have to explicitly enable. Well with my montor (and AMD card limited to HDMI 2.0 due the BS in TFA) it at least defaults to 60 Hz but there is no indication what the consequences of setting it to 120 Hz are. You're not even told that your connection has been downgraded by any OS I have tried. Absurd that you have to result to these test patterns.

_kb 3y ago

Another immensely useful source and pattern generator is also https://www.extron.com/article/testpattern https://www.extron.com/article/testpattern.

Cu3PO42 3y ago

I once had a bad cable, which forced a 4k@60 monitor into chroma subsampling. Or rather Windows decided it would rather enable Chroma subsampling than drop resolution or framerate. I immediately noticed there was something wrong. I agree it's terrible for desktop use. I would probably also have blamed freetype if it only happened on Linux, though.

account42 3y ago

> It will be fine for gaming I disagree. Gaming can involve lots of (colored) text too. And besides, if you have invested in a 4k@120Hz monitor are you really going to accept chroma subsampling even for non-text content? I hate how the connection just magically switches to chroma subsampling (and/or DSC with newer connection standards) instead of that being something you have to explicitly enable. Well with my montor (and AMD card limited to HDMI 2.0 due the BS in TFA) it at least defaults to 60 Hz but there is no indication what the consequences of setting it to 120 Hz are. You're not even told that your connection has been downgraded by any OS I have tried. Absurd that you have to result to these test patterns.