[Master One]

I'm currently testing LibreELEC x86_64 Nightly (Matrix) on my i7-10510U laptop with Intel UHD Graphics 620 connected to my ViewSonic PX747-4K projector by HDMI.

Intel UHD Graphics 620 supports up to 4K@60Hz over the (mini) display port, but only 4K@30Hz over the HDMI port (which is why I have just ordered a 4K@60Hz miniDP to HDMI adapter yet to arrive).

The projector effectively has a native resolution of 1080p and can do 4K@60Hz with pixel shift technology, which is why it makes more sense to generally run on 1080p@60Hz, except when viewing 4K content. It also supports HDR10, but according to some reviews the result is not overwhelming.

So far I have tried Kodi set to 1080p@60Hz and 4K@30Hz with dithering and auto refresh change set to OFF, but I have not seen any auto resolution switching. When switching auto refresh switching to ON (on start/stop with a 2 seconds delay), it changes the refresh rate, but not the resolution, and I honestly could not see any difference with the reduced refresh rate (typically either 24 or 30Hz with the content I'm using) compared to 60Hz (when set to 1080p). I'm not sure what effect dithering should have in my scenario, so I have left if OFF.

I could not find any setting for auto resolution switching and I'm not sure if my setup fits its usual usage case.

So what's the recommended setup for my scenario making use of 1080p as per native resolution of the projector, only switching to 4K to enable pixel shifting mode when 4K content is used?

And what influence does auto refresh change and dithering really have?

[DaVu]

Could you please get us a logfile?

[fritsch]

I'm currently testing LibreELEC x86_64 Nightly (Matrix) on my i7-10510U laptop with Intel UHD Graphics 620 connected to my ViewSonic PX747-4K projector by HDMI.

Intel UHD Graphics 620 supports up to 4K@60Hz over the (mini) display port, but only 4K@30Hz over the HDMI port (which is why I have just ordered a 4K@60Hz miniDP to HDMI adapter yet to arrive).

The projector effectively has a native resolution of 1080p and can do 4K@60Hz with pixel shift technology, which is why it makes more sense to generally run on 1080p@60Hz, except when viewing 4K content. It also supports HDR10, but according to some reviews the result is not overwhelming.

So far I have tried Kodi set to 1080p@60Hz and 4K@30Hz with dithering and auto refresh change set to OFF, but I have not seen any auto resolution switching. When switching auto refresh switching to ON (on start/stop with a 2 seconds delay), it changes the refresh rate, but not the resolution, and I honestly could not see any difference with the reduced refresh rate (typically either 24 or 30Hz with the content I'm using) compared to 60Hz (when set to 1080p). I'm not sure what effect dithering should have in my scenario, so I have left if OFF.

I could not find any setting for auto resolution switching and I'm not sure if my setup fits its usual usage case.

So what's the recommended setup for my scenario making use of 1080p as per native resolution of the projector, only switching to 4K to enable pixel shifting mode when 4K content is used?

And what influence does auto refresh change and dithering really have?

Hi,

that's a bit of a usability flaw. Kodi has a separate setting of a Whitelist for Refreshrate / Resolution changing. If the whitelist is not correctly configured (e.g. has entries, but the wrong entires) it won't switch as you have it in mind. By default - thought - with a configured whiteliste kodi will do: Find same resolution refreshrates _AND_ find matching refreshrates of a higher resolution, it won't switch down.

For your 30hz on a 60 hz Display, That's not really a problematic use-case, it just paints each pic twice, which will exactly match, therefore you don't see anything there. Really demanding would be the comparison of 24 fps on 24 hz in comparison to these 24 fps on a 60 hz screen. Here you clearly will see a difference as 60 divided by 24 is not an integer but a float.

Why it is not switching for you, only your Debug Log can help.

For Dithering: Depending on what you output: Intel is here very problematic since many years as it by default creates full range from limited range by default. For kodi only certain combinations of (xorg, kodi and tv, all of them must match) ways of setting make sense, which are highly influence by the system configuration (xorg, which kodi does not have in its hand) and are maybe not even available, see below.

a) You configure kodi to Output Limited Range (settings) and _force_ xorg to also output limited video range without touching the pixels. Sadly this kernel change never made it into the official kernel, I have no idea if LibreELEC still has it, it's many years ago when I wrote it. TV shall do Limited Range.
a2) You configure kodi to Output Limited Range (settings) and _force_ xorg to to output FULL range, which will leave our Limited Range pixels alone. That will though send FULL information frames to your TV and your TV will most likely switch to Full Range, but in this a2 hack mode, you have to force your TV to Limited range, so that black actually stays black. TV shall do Limited range (forced besides xorg sending full information frames).
b) You configure kodi to Full, you set xorg to Full via xrandr and you enable Dithering in kodi, so that during to Limited to Full color "upscale" some random pixels are added to make a more smooth experience. TV shall be configured to Full.
c) You configure Xorg itself to use 16:235 range, which - und der certain circumstances was the default for Intel with TVs - that will cause everything you output in Full-Range in kodi (which is why you have to set kodi to full here again) to be downdithered to 16:235 Range. So as it is goes "up" first in kodi, also keep dithering enabled here. TV shall be configured to Limited.

As you see: For kodi it always makes sense to turn on Dithering (with official kernels, for a) and a2) you can keep it off, but it does not harm) if you are on an intel gpu. And because of the "situation" a), all b and c have flaws.

Good look.