HDR Problems on S912 and S905

Thanks both for feedback. But I don’t understand why I can’t see correctly the video. I’ve checked and 10bits 444 is applied (AVR reporter it) and cat to atrr, also.
Can you check video published to test if you can view the same behavior?

Thanks

I just tried that video posted above, I can’t see banding or flashing myself, I’ll go recheck it with 8 bit output also so I can confirm 100%

I have seen 1 issue when starting the box that I’ve never experienced with any OE or LE builds I’ve tried, rarely the box is booting up at 480p when I turn everything on, I’d assume it’s an HDMI handshake thing or something but when I then goto the settings and manually set 1080p the screen goes to artifacts/double screen and only a reboot fixes it, i only have 1080 and higher in the display whitelist, log here : http://ix.io/1jOt

So, how can activate properly the 10bit, 444 option?

@Duke, so can you see the video properly, without any issue? Is strange. I tested in previous LE 8.2 and the same video, hardware cable, works, wihout banding.

i saw that @anon88919003 has reverted the autoswitch commit in GitHub. Why?

We have been testing this patch thoroughly, and it doesn’t work consistently.
There are often issues where the switch to 10-bit doesn’t happen when it should or happens when it shouldn’t. We are still looking for a proper solution to this issue.

Thanks @TheCoolest for the comments.
I’ve tested nightly build with the new commits introduced by @afl1 in the kernel!

Good news!! He solved banding problems in 10bits video! I’ve tested again the video, forcing 444,10bits option and works perfect. No banding! Then I restored the option to “reset” (like patch applied previously) and 8 bits video played perfectly.
I think that adding again the patch will resolve autoswitch HDR.

Thanks boys for this great effort @TheCoolest @afl1 @anon88919003

it seemed to be working as intended for me, and yes the banding was not present with the test file when outputting at 10bit

The guys at OSMC have done an extensive job of fixing up the HDMI driver. In 8.90.3 we made an attempt to switch over to the OSMC kernel. in 8.90.4 @Ray and me managed to solve the banding/flashing issues with 10bit HDR, but we had to drop those changes out in 8.90.5 because we went back to Kszaq’s kernel.
@afl1 has done a great job, he added all of the HDMI improvements from the OSMC kernel branch, including the banding/flashing fix we made in 8.90.4.

The issue with the automatic 10-bit switching still remains, though. It just doesn’t work reliably in all cases. So after a long discussion, we decided to remove it for now, until a working solution is found.

@Duke the problem primarily affected the S905X chips.

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@TheCoolest, any chance of a nightly with the auto 10-bit switching for S912 users? 8.90.2 seems to be the latest build that has auto 10-bit switching, which is what I’m running.
Thanks

@TheCoolest I’ve made little test. I used last build with HDR autoswitch and I substituted kernel with the lastest.
The results were pretty good. Autoswitch HDR 10bits, 444 worked perfectly with 4K video posted by @Arien (without color banding, no flickering). Then i tried a 8bits video, and switched to 8bits, 444.

My test system is a Minix U9-H S912, AVR with HDR support and SonyTV 4k.

8.90.2 used the kszaq kernel, with no improvements in that area.
8.95.0 should be the same from that respect.

@atomizasser sounds good.
We tested this internally before pushing, and we confirmed that the banding/flashing issue is now gone.
What needs to be said about the changes is:
If you play HDR content in 8-bit mode, you will get an HDR signal, but there will be banding. For HDR, 10-bit is a must now. In the past, there was a setting in the processor that enabled an internal dithering method to make 8-bit output signal have smoother gradation, that is disabled now. It means that in 8-bit mode, you will get a true 8-bit gradation.

We are working with OSMC to try and get automatic switching resolved and integrated into the kernel, instead of relying on Kodi patches. The main problem I found with simply leaving 10-bit forever was primarily with 4K SDR material would be oversaturated, because the display would go into BT2020 mode without HDR.

Edit: Sorry for a bunch of edits, please reread for clarity.

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@TheCoolest,
I’ve understood that banding issues are not present in older builds for S912 users with color space switching.

I don’t think color depth switching has ever worked on CE. I can’t say anything about the S912. From what I can tell, the code we based the banding/flashing fix on, had the correct configuration for the S912, so I’m not sure what was there in the past, it should work correctly now.

BTW, the guys at OSMC have tested the fix on their side, and confirmed that it is working as expected. But they do not test S912.

Hello.
I’m trying to compile by my own coreelec from github. Until now I’m using precompiled version from @Computerbastler18 dated on 10th August with kernel from 11th. It is working perfectly for HDR 10bits.
As on github @anon88919003 has reverted hdr autoswitch, now if I compile from source the patch is not apply. How can I revert the patch?
Thanks

  1. Make a fork and add the commit you need
    or
  2. Go to the commit you need, and save each file (view, raw, save as) and replace them in correct places of local directory

kindly link that devel version of 10 August kernal from 11 August because I accidentally deleted that version?

Thanks for your answer.
Linux-Amlogic is compiled automatically when I make my build? Or also I need to sync Linux-Amlogic tree?

Thanks

You can also revert the commit locally.

git revert 613aa65
git commit -m “reapply autoswitch patch”

Then delete the build.* folder, and make a new build.

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Thanks for your suggestion. I could build my own build perfectly. Until a definitive fix could be integrated into coreelec, the auto switch hdr workaround is working.
Thanks guys for your work.

I saw OSMC commit, If you need some tester to test OSMC fix on S912, please do not hesitate to tell me.

Regards

The autoswitch does not work correctly, you may think it does but it doesn’t, some times it will trigger and other times it will not and then other times non-HDR content is recognised as HDR.

im still running it, i have noticed it not work, i also have not tested it with SDR uhd content, its pretty much 98% working tho, its only not correctly done the HDR 10 bit switch twice now for me. i noticed recent pulls addressing this again in a different way, ill keep testing and post results.
Thanks for the hard work, i was debating getting a shield tv but ill hold off for now, with older versions of different OS’s i always had audio issues with 10 bit enabled and the one build that offered 444 10bit auto switching seems to just lock up randomly all the time for me. CoreElec is working pretty darn good i must say.