Retroarch BFI - flickering in games under 60fps

[Papadon]

Hi all,

Recently picked up a Asus VG279QM 280hz monitor for the purpose of replacing my giant CRT for retro gaming. Long story short, everything on console in Retroarch (SNES, NES, GENESIS, etc.) works AMAZINGLY with the Asus ELMB and Freesync, along with 180hz refresh rate and 2 frames of BFI. The motion blur is reduced so much that it's extremely close to my CRT, in my opinion.

The problem lies in trying to do the same thing in Retroarch with arcade games, using any of the main cores like MAME, FB ALPHA, FB NEO, etc. Since some of the arcade games run at less than 60fps; Double Dragon, Final Fight, Mortal Kombat (all 54-58hz), the BFI pulses/flickers and it's extremely visible and annoying. The only way to fix it, is it ensure that Freesync (Sync Exact Content to Framerate setting in Retroarch) is turned off, which forces that arcade roms to run at 60fps instead of their native speeds of mid to high 50's.

The problem is that having to do this results in the annoying frame stutters and scrolling issues caused by forcing things up to 60fps. So, I either have to deal with the stutters and BFI works perfectly, or smooth scrolling and no stutters but BFI flickers/pulses like crazy.

I've reached out to log the issue with Retroarch but haven't heard back on their testing. I'm wondering if anyone out there can test this out and let me know their results and if there are any workarounds? It's the only thing holding me back from a full CRT replacement at this point, and I'm hoping it can be resolved.

Thanks!

[Chief Blur Buster]

Hi all,

Recently picked up a Asus VG279QM 280hz monitor for the purpose of replacing my giant CRT for retro gaming. Long story short, everything on console in Retroarch (SNES, NES, GENESIS, etc.) works AMAZINGLY with the Asus ELMB and Freesync, along with 180hz refresh rate and 2 frames of BFI. The motion blur is reduced so much that it's extremely close to my CRT, in my opinion.

The problem lies in trying to do the same thing in Retroarch with arcade games, using any of the main cores like MAME, FB ALPHA, FB NEO, etc. Since some of the arcade games run at less than 60fps; Double Dragon, Final Fight, Mortal Kombat (all 54-58hz), the BFI pulses/flickers and it's extremely visible and annoying. The only way to fix it, is it ensure that Freesync (Sync Exact Content to Framerate setting in Retroarch) is turned off, which forces that arcade roms to run at 60fps instead of their native speeds of mid to high 50's.

The problem is that having to do this results in the annoying frame stutters and scrolling issues caused by forcing things up to 60fps. So, I either have to deal with the stutters and BFI works perfectly, or smooth scrolling and no stutters but BFI flickers/pulses like crazy.

I've reached out to log the issue with Retroarch but haven't heard back on their testing. I'm wondering if anyone out there can test this out and let me know their results and if there are any workarounds? It's the only thing holding me back from a full CRT replacement at this point, and I'm hoping it can be resolved.

Thanks!

You may want to test multiples of the low Hz, such as (54Hz x integer) and (58Hz x integer) with these specific games. I recommend 3x or 5x the emulator refresh rate (immune to burn-in), rather than 2x or 4x (image retention on some panels)

Create these custom refresh rates in order to get smooth operation with BFI -- that's the only way to do so.

For easier operation, the other options is to convince them that that BFI code should be upgraded to become VRR compatible, so that software can auto-adapt the BFI in real time to the frame rate, as BFI is refresh rate multiple dependent to avoid flicker/stutter.

You may want to add this feature request to RetroArch's GitHub "Make BFI compatible with VRR for easier BFI operation of 50Hz, 54Hz, 58Hz, 60Hz games" and reference the BFIv2 https://github.com/libretro/RetroArch/issues/10754

[Papadon]

Thanks very much, CRU created rates of 164, 172 seem to work pretty well to cover most of the games, and they also appear to work fine with 60fps console games too. At least, I cannot notice any additional flicker, etc.

[Kuscheln_Hammer92]

Sorry for reviving a dead thread. Bfi can cause burn in? Can that impact my ViewSonic xg2431?

[Chief Blur Buster]

Sorry for reviving a dead thread. Bfi can cause burn in? Can that impact my ViewSonic xg2431?

Let's correct this by distinguishing hardware-based strobing (PureXP) and software-based strobing (Software BFI).

If you're using the strobing feature built into XG2431, it won't affect anything.

It only affects software-based black frame insertion (e.g. DirectX-generated black frames), and there's mitigations. See This Thread about how Software Black Frame Insertion Interferes With LCD Inversion, and mitigations. That's why some boxes like Retrotink 4K has an "LCD Saver" feature.