OSSC Pro: BFI not working correctly (especially) at 120hz on Samsung G8 OLED

[koodoonas]

Hello

BFI works on 2x50hz but there is some periodic (~1s) perceived brightness shift
On 2x60hz I only get the brightness shift, there is no 60hz flickering

Tested with Game Mode both off and on, OSSC Pro fw 0.74 and 0.75
Monitor reports 100hz and 119hz VRR input accordingly

I initially thought it was because I hadn’t installed a fan in my OSSC Pro, but the behaviour is the same now that I have one

Monitor firmware 1662.6

I have uploaded a video of the issue here (download to get full quality):

https://drive.google.com/file/d/1ri0TJVjA_BjFu-tDThe17PTpf8X4IELq/view?usp=sharing

Thank you!

 

[marqs]

Have you turned off every picture processing / enhancement option on the TV?

[koodoonas]

Yes, of course, I’ve turned off Contrast enhancer etc. Besides, 100hz mode would be affected as well.

“Game mode” supposedly is the lower latency mode and it exhibits the same symptoms either off or on.

Same behavior on 720p120hz output, as well as framelocked to 120hz instead of x2 (regardless of input hz)

I can’t rule out the monitor as its firmware still has some issues, but it works fine at 120hz connected to a PC through the same cables and I don’t have another one to test.

Any ideas on how to test further are welcome, thank you

• This reply was modified 1 year, 1 month ago by koodoonas. Reason: clarification

[marqs]

Can you test if

* all 4 different 1080p120 modes (if supported by the TV) have the same issue on test pattern?
* you see the same with PC input (RetroArch BFI etc.)?

[Zacabeb]

Could the BFI simply be confusing the algorithms in the display that build the histogram for tone mapping? Even though the camera shutter interferes making the problems look somewhat different from what they do in real life, it seems that the display is trying to ramp up and down the brightness in response to the BFI similarly to how it would when tone mapping regular HDR content, but overdoing it because of the fast switching between picture and black frames.

How is it affected if adjusting BFI Strength on the OSSC Pro?

[koodoonas]

tl;dr it was the VRR

I had trouble making BFI work in Retroarch until I disabled VRR in the monitor’s settings (even though I had a fixed 120hz display mode in Windows).
After that it worked flawlessly.

BFI works correctly in both 100 and 120hz with OSSC Pro, only if I disable Freesync in its settings and also disable VRR in the monitor’s settings.
120hz BFI though only works correctly on non Framelocked 120hz (not in x2 mode), but this is probably the monitor having trouble displaying 59.28hz x2

Thank you everyone for your suggestions!

• This reply was modified 1 year, 1 month ago by koodoonas. Reason: clarification
• This reply was modified 1 year, 1 month ago by koodoonas. Reason: formatting

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