The VideoLAN Forums

I have two 2.5K DP displays (primary left, secondary right) each connected via a TB3 port on my system (MacBook Pro in clamshell mode), no other apps running.

When I play / steam video and VLC is on the primary screen with the window within 55px of secondary screen, the video starts to get jumpy rather than play smoothly, the audio continues to play fine though. This only happens within this 55px area, if the window is elsewhere, if I drag the window even 1 px onto the second screen, if I put the window fully on the second screen right next to the primary, if I switch VLC to full screen mode on either display, it plays fine, it's only if VLC player is within 55 px of the second screen...

Latest MacOS (14.5) & VLC (3.0.21) running on MacBook Pro M2 Max, Mission Control "Displays have separate Spaces" is turned off, VLC HW Decoding On/Off doesn't make a difference, video type doesn't make a difference (Xvid/H264/H265). It's been doing this for at least the last few months.

Anyone else have this issue?
Any thoughts?

Does turning on "Displays have separate Spaces" makes any difference for this issue?

(Note that I think you need to log out and log back in for this to take full effect)

I just tested it, yep, everything plays fine when "Displays have separate Spaces" is turned on (log out was required). (though I keep it off so I can span windows across the displays)

My initial thought was that maybe there's something about how MacOS creates a virtual desktop then cuts it up per display that causes a reduction in display frame rate, but it was odd that it was only if the window was in that small region (which also falls entirely on a single display)... Also, QuickTime doesn't have the issue (different method of display?), so maybe it's the method VLC is using to render the video to the display (I wasn't sure if there was some settings I could tweak and try). The only other app I've noticed with this issue is OpenOffice/LibreOffice, the interface is sometimes very laggy when near the screen seam (but from either side), but turning off it's setting "Use Skia for all rendering" solves that.

Do you have multiple screens? Does it do this for you as well? (to tell if it's somehow hardware related to my setup, cables maybe?)