HDR on x86 Hardware

Hi chewitt ,

I have a Beelink SER8 with AMD 8845HS CPU and AMD Radeon 780M GPU and everything plays perfectly except HDR which is too bright and the colors are "off" compared to all my other boxes (AmLogic AM6B+ or Homatics, Zidoo Realtek or Kodi in Windows on the very same Beelink AMD box).

I tried my HDR videos in VAAPI HW mode and in FFMPEG SW mode on LibreELEC 12.0.2 official stable, LibreELEC 13 latest nightly and your version here:
https://chewitt.libreelec.tv/testing/LibreELEC-Generic-gl.x86_64-12.80.2.img.gz

The problem is present on all the versions and modes.

In my other thread others said it might be a bug in Mesa or the driver. Since I tried your version of LibreELEC I think I already got the mostly latest amdgpu driver in the process (or maybe I'm mistaking I am not a Linux pro)? So that leaves Mesa possibly being the culprit but I don't know how to get in touch with the Mesa guys.

Are you aware of that problem and is there is a fix for it? Like I said in Kodi in Windows on the same Beelink AMD box the HDR is displayed properly.

If I get an Intel based mini PC instead will the HDR have the same overbright and colors "off" picture or is there a chance they will display correctly?

If so, can I get a very recent Intel mini PC with Arc GPU like this one:

ASUS NUC 14 Pro AI Mini PC, DDR5 5600 32GB RAM&1TB PCIe 4 SSD with Intel Core Ultra 7-155H Processor(16C/22T/24M Cache, Up to 4.8GHz) Intel Arc Gpu/AI GC/AI Boost/AI Ready/Type C 3.2/8K/BT5.3/WiFi 6E

https://www.amazon.ca/Intel-Ultra-7-155H-Processor-4-8GHz/dp/B0D7M3RD7S

Or is it better to go with an older Intel CPU for correct LibreELEC/Linux support like this one:

Intel NUC 13 Pro, Arena Canyon NUC13ANKi7 Mini PC with Core i7-1360P Processor, Intel Iris Xe Graphics, 32GB RAM&1TB NVMe SSD (12C/16T/18M Cache,Up to 5.0GHz) Support 8K/WiFi6E/BT5.3-Win11 Pro

https://www.amazon.ca/dp/B0DK8JJ249?ref=emc_p_m_5_i_atc

My goal is to SW decode everything up to 8K 60 fps (downscaled to 4K 60fps by LibreELEC) for best PQ so I would prefer the first Asus NUC one with the newer Intel CPU because that would be roughly equivalent to my 8845HS I currently have.

Does LibreELEC correctly use all performance and efficient cores of an hybrid CPU like that Core Ultra 7-155H ? My current AMD 8845HS is a simple 8 cores / 16 threads performance cores and I can see in LibreELEC that all cores are being used and I go up to 60-65% usage with an AV1 8K 60 fps video in SW decoding.

Thanks in advance for your help and support!

Software downscaling 8K media to 4K sounds like a bad idea. If you want to use 8K media get an 8K capable TV and play content at the native 8K mode of the panel. Configure Kodi along the lines of https://wiki.libreelec.tv/configuration/4k-hdr and allow the TV to upscale 4K and 1080p modes to the 8K native panel resolution. The article doesn't mention 8K at all but the same issues and basic principles apply.

As a general rule Intel seem to be more active in maintaining drivers and nVidia is on the long-term 'avoid' list as drivers still require X11 (so no HDR) but I haven't personally used Intel/AMD/nVidia hardware for more than a decade now so I can't really comment on the current state of anything.

I would personally guess the issue is more likely to be in the kernel DRM layer than mesa, and more likely to be incomplete drivers than a bug in something. There's no factual basis for the comment though, I'm just guessing.

8K is just a bonus, I pretty much only use 4K and want to SW decode everything with ease.

I got the asus and will report back if hdr looks correct.

Thank you for the reply!

I got the ASUS NUC 14 Pro and yes the HDR is now correct on Intel Arc GPU but there are drawbacks too versus AMD:

- The device is a vacuum cleaner noise-wise compared to the Beelink SER8 8845HS which I never hear. The Beelink Gti14 Intel Ultra 7 155H is as silent if not more compared to my SER8 AMD according to reviews so I got the wrong NUC for the noise by choosing ASUS.

- The HDR always play in 8 bits so it's wrong because of the bit depth.

- I have HDMI sync problems. If I switch inputs on my AVR and go back to the ASUS NUC my image rarely returns. Very annoying. The AMD does not do this. Also, I have a 1080p59.94 video that when I try to play it and the device switches to that res to match it I also loose HDMI sync pretty much all the time so it's hard to play those. Again AMD no problem on resyncs.

- I need to use LibreELEC 13 as LibreELEC 12 stays stuck on the LibreELEC boot logo. I read that Intel Arc started at Linux kernel 6.6 and that's the very first driver so I guess LibreELEC 12 is too old. The thing is, LibreELEC 13 is probably not stable yet.

Is there a fix someone can think of or that is already known for the HDR being always in 8 bits on Intel Arc?

Is there a fix also for my HDMI resync problems? I am using one of the HDMI 2.1 TDMS port on the device. The only other option would be a USBC to HDMI 2.1 adapter but I would prefer not to go that route.

On the AMD side, I wonder if it's possible to fix that wrong HDR too, maybe a manual update of the driver? I already tried chewitt's latest build 12.80 though so I don't know if there's anyway newer on the amdgpu side. How do you update that driver manually?

Quote from smp

Diff

diff --git a/intel_hdmi.c b/intel_hdmi.c
index ed29dd0..ef293a3 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2060,7 +2060,7 @@ intel_hdmi_mode_valid(struct drm_connector *connector,
 	if (clock > 600000)
 		return MODE_CLOCK_HIGH;
 
-	ycbcr_420_only = drm_mode_is_420_only(&connector->display_info, mode);
+	ycbcr_420_only = drm_mode_is_420_only(&connector->display_info, mode) || clock > 500000;
 
 	if (ycbcr_420_only)
 		sink_format = INTEL_OUTPUT_FORMAT_YCBCR420;
@@ -2265,8 +2265,9 @@ static int intel_hdmi_compute_output_format(struct intel_encoder *encoder,
 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
 	const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
 	const struct drm_display_info *info = &connector->base.display_info;
-	bool ycbcr_420_only = drm_mode_is_420_only(info, adjusted_mode);
-	int ret;
+   int clock = adjusted_mode->clock;
+   bool ycbcr_420_only = drm_mode_is_420_only(info, adjusted_mode) || clock > 500000;
+   int ret;
 
 	crtc_state->sink_format =
 		intel_hdmi_sink_format(crtc_state, connector, ycbcr_420_only);

Display More

^ This kernel patch would force 4:2:0 12-bit for 4K 50/60Hz. You'll have to build your own custom LE image to apply this.

Thank you for this. I am a programmer but I don't know how to compile my own LibreELEC. I guess I follow the wiki page for Build?

By the way, even 4K 24 fps HDR videos playback at 4:4:4 8 bits on my Intel Mini PC so it's not only about the HDMI bandwidth this time. It seems everything is stuck in 4:4:4 8 bits. Maybe Intel Arc is not well supported yet?

On my AMD mini PC I did the following tests:

I used a Display Port to HDM 2.1 cable test on my AMD system except of using the HDMI 2.1 port and the HDR is closer to correct using that method but the colors are washed out in the GUI and in the playback too just like when you are not in the correct color range (Full vs Limited) but if I put limited it's even more washed out so it's not a solution. The video AV1 4K 60 fps HDR video played in 4:2:2 12 bits too if I use my HDMI 2.1 port on the AVR and TV versus 4:4:4 8 bits (changeable to 4:2:0 12 bits with the driver configuration force_4_2_0_video).

I now understand that HDMI forum blocked HDMI 2.1 support on the amdgpu open source drivers only for HDMI ports but not for DP to HDMI 2.1 or DP to DP connections.

Tomorrow I receive a USB4 to HDMI 2.1 adapter so I will try that but I expect the same thing than with the DP to HDMI 2.1 cable.

So, in short on my AMD 8845HS + Radeon 780M system:

If I use the HDMI 2.1 port:
- HDR plays too bright with too saturated colors
- Video plays in 4:4:4 8 bits or 4:2:0 12 bits if I use the force_4_2_0_video option in the drivers

If I use a DP port to HDMI 2.1:
- HDR plays at the correct brightness but colors are washed out
- Video plays in 4:2:2 12 bits

chewitt I think your version 12.80.2 image uses Linux kernel 6.12. Is it possible to make an image that uses 6.13 or the latest 6.14 please so that I can see if MAYBE AMD fixed the HDMI port HDR?

I tried Ubuntu but HDR in Ubuntu seems pretty useless as mpv, vlc, etc. are not using DRM from what I understand so far.

I tried hdmi port direct to TV and I don’t loose the picture on syncs anymore but sometimes the image freezes for some seconds on video playback stop and at some point LibreELEC rebooted by itself on a video playback stop.

I cannot see bit depth of playback because the AVR was the only one telling me that information and i don’t have other hdmi processors.

This ASUS intel mini pc does not seem as stable as my amd mini pc on my setup.

Is there a chance that if I get the Beelink Gti14 with the same intel ultra 7 155H cpu that the hdmi port will be different enough to be more compatible or is it almost certain it will be the same behavior? There seems to only be the Beelink Gti14 Ultra 9 185H at amazon.ca so that would be the one I get. It's supposedly as silent as the Ultra 7 155H Beelink and I saw a review of the Gti14 Ultra 7 155H and it's very silent compared to the ASUS (noise becnhmark). It was the most silent in the list at 32-33db max.

In any case I will not keep this asus because the fan is too much of a vacuum cleaner so the only thing I am wondering is if I try the Gti14.

Also, I will receive my USBC to HDMI 2.1 adapter tomorrow or wednesday so I will test that on the Intel and AMD mini pc.

I got the USBC to HDMI 2.1 adapter, the results are:

- On the AMD Beelink, the colors in the GUI are not washed out anymore versus when using the display port to HDMI cable but when I play an HDR video the colors are quite washed out like someone turned down the color on my TV to quite a lower amount. The HDR 4K 60 video plays at 4:2:0 12 bits instead of 4:4:4 8 bits with the HDMI 2.1 port directly.

- On the Intel ASUS, the colors in the GUI are ok but the HDR video has the same washed out picture than on the AMD and the video still plays at the stuck 4:4:4 8 bits value. Also, the AV1 4K 60 video freezes after 3 seconds of playback but that also happens when I use the HDMI port. No freezing on the AMD on any port.

So, HDR is not exactly stable on LibreELEC with Generic x86 it seems. I think HDR was introduced in LibreELEC 12 so it's kinda new I guess.

I will probably just use my Amlogic devices with CoreELEC for HDR. It's a bummer but it sounds kinda hard to get a powerful mini PC with correct HDR.

Maybe if I go back to Intel Iris Xe on a Beelink intel 13900HK or intel 12900HK the HDMI port, HDR and stability would be better?

Quote from Creator44

It's a bummer but it sounds kinda hard to get a powerful mini PC with correct HDR.

Get a Mac mini M4 or an Nvidia Shield.

I have nvidia shield but the pq is not as good and theres red push even in sdr because of color space problems.

Why the mac mini m4? Will it run LibreELEC? I don’t think so? Does kodi run perfectly on macos with hdr, resolution switching, framerate switching, audio passthrough, in sequoia? I doubt it but maybe?

Quote from Creator44

Why the mac mini m4? Will it run LibreELEC?

Because it's a powerful mini PC with HDR. I don't see Kodi in the M4 app store, and we don't support it. However, it can run Linux, so you can autostart Kodi on it. Do some research, it's not our turf.