Fullscreen Optimaztion cannot be disabled, breaking VSync and causing jitter

[unleashed7]

I spent about 4 hours trying to fix MPV, while the problem was Windows and its FS optimazion all along.

This issue is specific to Shim as I couldn't replicate it with fresh install MPV, for some reason Shim is treated differently by Windows.

FSO activates if Shim is in fullscreen, windowed-maximize mode or even if it's windowed, if the window matches display resolution and you drag it perfectly in the middle (shown in example below)

Issue can be seen here: (I can't drag perfectly in the center at first, only second try, then the screen goes to black for a split second when FSO activates)
https://imgur.com/a/SHIR4L8

The problem is that it cannot be disabled for Shim with compatibility>disable FSO on run.exe, as probably it's just a wrapper and MPV launches separately when casting starts, not being affected by this setting.

I'm sure the problem is linked to this, as my solution is tricking Windows by simply using:

no-border
autofit-larger=100%x100%

And having taskbar auto hide. Then after the video launches exit fullscreen with "f", it flashes once (turning FSO off) and works fine.

So in the end I'm running it in windowed mode, but at least without the FSO activating (having vsync on) and without jittering really hard,

Is there a way to fix this in Shim? Why does Windows treat differently the MPV instances launched by Shim, than launching just MPV?

• OS: Windows 10 19043
• System: Dell Inspiron 3501 (11th Gen i5-1135G7 with Iris Xe)

[JPVenson]

Could you please explain what "FS optimazion" is and upload the screenshot to github instead? (it is deleted on imgur)

Could you please elaborate what exactly the issue is here?