Update - just compared the captured bars from the Pi 4B with the native bars from the EBU test file in Resolve and they appear identical. I think this suggests that things are good.
Awesome, this is really good news! Huge thanks for going through all the effort and checking this!
so long,
Hias
Downloads->Raspberry Pi 4->LibreELEC 10.0 Beta
so long,
Hias
Here's a new testbuild, now with - hopefully - correct BT.2020 YCC->RGB conversion matrix:
LibreELEC-RPi4.arm-10.0-devel-20210412194217-d08d2e1.tar
noggin do you have a possibility to verify with your HD-fury if the conversion matrix is OK now? popcornmix's HDMI analyzer doesn't seem to have picture/color analysis features and visual testing is quite a PITA as I don't have an easy-to-use known-good reference to compare against (my TV's built-in player sucks, it completely exits after switching to HDMI input so I can't easily switch back-and-forth).
Of course feedback from others is highly welcome, too!
so long,
Hias
Even on LE 10 Beta?
yes, config.txt is still the place to configure overlays and bootloader/firmware specific settings.
so long,
Hias
Yes, /flash/config.txt is the correct place for it. Add a line with eg "dtoverlay=cma,cma-384" at the end of the file to reduce CMA memory size to 384MB. See the README in /flash/overlays for more info about syntax and allowed options.
so long,
Hias
Video decoders and the graphics driver now use CMA memory which can be shared by other (userspace) programs.
By default we use 512MB CMA, previously we used 384MB but that was not enough to handle all 4k HEVC files. This can be tweaked with the cma dtoverlay - but keep in mind that if you reduce CMA memory you risk running into video decoder / graphics issues.
No idea about docker, best you open a separate thread about it or discuss in the thread you linked.
so long,
Hias
If you run LE 10 then leave gpu_mem at the default (76MB). It's only needed for H.264 hardware decoding. Setting it higher just wastes memory.
so long,
Hias
Is it possible to update to the nightly build with hdr support and keep all my other addons and settings in kodi?
And if possible how do I instal this nightly build ?
And can I downgrade back to 9.2.6 if needed?
Or is it better to take a New sd card and fresh install with latest nightly build and reinstall my addons?
Can you make a New sd card with nightly builds with the usb-SB creator?
It's best to do a fresh install of the official LE 10 beta 1 release (or the latest nightly build) on a separate card and then update it with the test build (copy the tar file to the Update share via SMB or to the /storage/.update/ folder via scp and then reboot).
Upgrading from LE 9.2 is not supported (it might work, but depending on installed addons you can end up with a real mess) and downgrading isn't supported at all (you'll definitely end up with an unusable system).
The test builds I post here in this thread only contain a few additions that aren't in current nightly builds and if testing goes fine we'll include the changes in LE 10 / nightlies - switching from the test builds to LE10 nightlies or the next official release will work without issues.
so long,
Hias
Create a /storage/.config/kodi.conf file with the following line
LIRC_SOCKET_PATH=/var/run/lirc/lircd.irtransso long,
Hias
Not sure I get the 'whitepoint' stuff
Sorry, I should have better avoided the term "whitepoint" in this context. What I meant was what you mentioned later, due to the wrong matrix the RGB values won't be quite correct, colors skewed, and white won't be white.
4kp50/60 output isn't implemented in this build, this is still in the queue (we tested an early patch a few weeks ago but it's not 100% there yet).
4kp50/60 HEVC decoding is more performant now, so 1080p50/60 output of such files will be a lot better (previously the decoder couldn't keep up resulting in a/v sync drifting away). These optimizations are still WIP but testing showed it's already mostly working fine.
so long,
Hias
If you are in the mood for some experimental testing here's a new testbuild to try:
LibreELEC-RPi4.arm-10.0-devel-20210409193846-98e0bda.tar
Kodi and video driver now signal BT.2020 colorspace, my LG C8 now shows BT.2020 in status info (which it didn't before).
Conversion matrix in video driver is unchanged so whitepoint most certainly isn't right. 10/12bit output is still missing as well, but hopefully we're one step closer to correct HDR output.
The build also contains current WIP HEVC optimizations and latest kodi Matrix changes. High-bitrate and 50/60fps HEVC videos should perform better now but beware, there might still be bugs 
so long,
Hias
Thanks for the report! I could reproduce the issue, it seems to be caused by the LibreELEC settings addon. I've created a github issue to track that here: [BUG] LE settings addon causes crashes when switching profiles · Issue #5303 · LibreELEC/LibreELEC.tv · GitHub
so long,
Hias
I'd recommend testing with video=HDMI-A-1:1920x1080M@60D added to the end of /flash/cmdline.txt first. See eg here RE: getting log files
If your monitor doesn't support full HD then use eg 1280x720M@60D.
Also drop all the hdmi options you added in config.txt.
If you get a picture then ssh in and run "vcdbg log msg" and post the output you got.
so long,
Hias
This is no longer possible by default. You could try using pulseaudio or creating an asound.conf file to do this (search the forum for more info), but I wouldn't recommend that as it isn't actually hassle-free.
so long,
Hias
Please test with the latest nightly build from here: Index of /
Also note that the hdmi options in config.txt won't have any effect in LE 10 - you now have to use drm.edid_firmware and video kernel command line options like on x86 and all other linux systems if you need to work around video issues.
so long,
Hias
Best place to track would be to create a github issue Issues · LibreELEC/LibreELEC.tv · GitHub - please add a link to the sample file there, too and a link to this forum thread
so long,
Hias
The user never mentioned the LE version. For LE 9.2.6 it's the config.txt way, for LE 10 Beta it's kernel options.
of course he did - have a closer look at the picture in post 11 RE: Is there an autostart script that will run if LE doesn't detect a monitor?
so long,
Hias