HDR Slight flickering (Workaround available)


sorry. got it to work eventually but the flickering is still present :frowning:


Thanks! I’ve done the update and will test it after work. Fingers crossed!


I don’t experience the flickering with some previously problematic content now after these changes.

Is your file encoded correctly / did you rip it yourself? Some of the HDR samples are quite good for testing

It’s also possible your device didn’t update as expected, in which case you will get these changes in a few days time anyway.



I don’t know if the files are encoded correctly but I do know that they played ok on the shield TV. I also notice that the problem disappears if I force them to play at 2160 60hz


Is the content actually being output as HDR on the Shield?

Your TV should give you an indicator of whether it’s receiving an HDR signal or not.
It’s possible that at 2160p60 your TV isn’t receiving an HDR signal and as such you see no flicker.



My TV shows a banner in the upper right when HDR content is being played. It’s also fairly obvious as the peak brightness is significantly different for HDR content in comparison to my calibrated ISF Standard mode. I can confirm that the Shield TV displayed the HDR banner when playing the content and I can confirm that the HDR banner also displays when playing at either 24Hz or 60Hz on the Vero 4k. 60Hz shows no flicker whereas 24Hz does.

I look forward to Martorias’s tests once he has had a chance to check out the update.


Hi, I just tested and the issues are still there :frowning: Feeding a 24fps HDR video gives green/red color flickering issues, and feeding 60fps HDR video gives “crawling” in very bright areas.


Okay – thanks for confirming, I’ll keep digging.



Do you have access to an OLED tv to see the issue first hand?


Also can anyone give me a hand to install that callback script listed above?


Kodi Callbacks is an add-on.

http://kodi.wiki/view/Add-on:Kodi_Callbacks should get you up and running.


I do – although sometimes getting access to it can be tricky :wink:


I have the same issue which I have semi-fixed (I’d much rather be able to play this stuff at 24fps to avoid stutter) with the kodi callbacks trick to switch to 2160p60 but I’m confused to where the issue really is.

How does my real UHD player display 2160p24 in HDR on my LG OLED B6 if the Vero 4K does not seem to be able to? What colourspace/signal etc is that sending to the screen that the Vero cannot replicate?


There was some discussion about that earlier here: HDR Slight flickering (Solved for now).

There seem to be some limitations with LG OLED displays, but nothing to suggest the cause of a flickering.

The player will be able to output in the same formats as Vero 4K and vice versa. This is defined by the HDMI standard. It may be possible that some formats produce less visible flickering.

The TV or player may have a settings option to display the output format.



Unfortunately the stupid LG OLEDs have no way of showing output information apart from resolution and HDR status. You can’t see the refresh rate or other useful information like colourspace sadly but I may be able to get something from my amp.

The flickering at 24fps is very strange and something I’d love to get resolved rather that having to use 60fps for 24fps content and get slight stuttering. I appreciate there may not be much you can do from your end if its simply an LG issue but I’m happy to test any code/theories out if you have any further ideas.



Can you give me the model number (exact) you have?

I wonder if I need to pop in to Richer Sounds or John Lewis again and test a few TVs…


I have this model from 2016:


You might have trouble finding this model now in any shops as it was replaced by the B7 model earlier this year.


I stumbled upon this:


But it only seems to refer to older LG displays I think. There is some mention of HDR problems with B6 series:


I have had a look at the specs of your TV and it looks like it supports 12-bit.

Try this in /etc/rc.local before exit 0:

echo '422,12bit' > /sys/class/amhdmitx/amhdmitx0/attr

I’ve been working a little on optimising some defaults out of the box for some TVs. If we reach a consensus for improvements for some displays; I’ll add some EDID parsing logic to the kernel to autoconfigure modes for the best possible output.



Thanks, I’ll try that out later today, I’ve been using the previous recommendation of ‘444,10bit’ so far.

The firmware of the TV is still maintained so hopefully if it is an issue with the TV itself I may be able to get them to fix it if I can detail the issue.


You can see some information by pressing the scroll button on your remote when the pointer is visible. This will show the output name and if you click that you will see resolution, and if the hdr mode is enabled it will show BT2020, aside from the HDR pop-up.