So did it get any better with LibreELEC nightly builds? In a couple of months Kodi 19 should be ready so I am asking the alpha and beta testers if it's still stuttering on Intel NUCs w/ 25Hz content.
I'm currently running LE nightly on a RPi4 2GB, CPU overclocked to 2 GHz. Not sure how much of this applies to Intel NUCs, though.
With DRM Prime decoder, Hardware Acceleration and HQ Scalers enabled, i haven't yet experienced any stuttering.
With DRM Prime & Hardware Acceleration disabled, i need to disable HQ Scaling for smooth playback - the CPU obviously can't keep up with both software-decoding and CPU-intensive scalers.
One quirk that still bugs me is that slowdown of PAL material to 24 FPS doesn't work right now. With earlier versions (don't remember wich, but definitely pre-Leia) this was possible by enabling Sync Playback to Display, whitelisting 24 and/or 23.76 FPS refresh rates but disabling 25 FPS.
At least with current stable and nightly builds, this behavior seems to have changed. Even if i set an override in advancedsettings.xml, there's one frame being dropped every second instead of the video being slowed down to 24 FPS.
Other than that, everything plays smooth for me.
Also, the brief stuttering when the OSD fades in/out is gone in recent nightly builds.