When content is played back at a frame rate below the monitor’s minimum VRR range (e.g., 24, 25, 30 fps on a monitor with a 48–160 Hz range), Low Framerate Compensation (LFC) does not engage correctly. Instead of stably duplicating frames to keep the refresh rate within the supported range, the monitor’s refresh rate continuously oscillates between the minimum and maximum values (48 Hz ↔ 160 Hz), causing noticeable stutter/flicker.
Content played back within the range (50, 60 fps, or any rate between 48–160 Hz) works normally, with no oscillation.
Steps to reproduce
Connect a monitor with VRR enabled (48–160 Hz range) via HDMI.
Enable Adaptive Sync/VRR in Plasma’s display settings (Wayland).
Play a video with a frame rate below the range’s minimum (e.g., 24 fps, 25 fps, or 30 fps) using mpv.
Observe the refresh rate reported by the monitor (monitor OSD) or via a measurement tool (e.g., VRRTest).
Expected result
LFC should multiply the monitor’s refresh rate by an integer factor (e.g., 30 fps → 60 Hz, or 24 fps → 96/120 Hz) and keep the refresh rate stable within the supported range, with no noticeable oscillation — behavior equivalent to what’s seen on Windows.
Actual result
The monitor’s refresh rate keeps switching back and forth between the minimum (48 Hz) and maximum (160 Hz) values of the range, instead of stabilizing at a multiple of the playback frame rate. This causes visible stutter/flicker throughout playback.
RTX 5080
Plasma 6.7.4
Wayland
Nvidia driver 610.57.04