Speaker
Description
Problem Statement
Compositors are unaware of the media content frame rate and therefore present frames using the display's default refresh cadence. This mismatch leads to irregular frame timing, causing judder during low-frame-rate video playback (e.g., 24/30 fps) on both fixed-refresh and VRR displays. A familiar example is 3:2 pulldown, where 24 fps content is displayed on a 60 Hz panel with alternating 3- and 2-refresh frame durations, resulting in uneven motion. Figure 1 illustrates a similar issue, showing how 30 fps content is presented with irregular frame timing on a 40–60 Hz VRR display.
Figure 1
https://github.com/k2naveen/xdc-2026/blob/main/media-playback-frame-judder.png
Solution
To address this, we propose the wp-content-frame-rate-v1 [1] Wayland protocol, enabling media players to communicate the content frame rate to the compositor. The compositor [2] uses this information to apply Low Frame Rate Compensation (LFC) on VRR displays by selecting the lowest stable refresh-rate multiple of the content frame rate, or to switch to a matching supported display mode on fixed-refresh displays, delivering smooth, judder-free playback.
[1] https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/518
[2] https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/5091
| GSoC, EVoC or Outreachy | No |
|---|---|
| In-person or virtual presentation | Virtual |
| Code of Conduct | Yes |
