https://bugs.kde.org/show_bug.cgi?id=517961
Bug ID: 517961
Summary: Background content behind some fullscreened apps
flashes briefly and randomly around the edges when
sharing a monitor via OBS "Screen Capture (PipeWire)"
on KDE Plasma Wayland
Classification: Plasma
Product: kwin
Version First 6.6.2
Reported In:
Platform: Arch Linux
OS: Linux
Status: REPORTED
Severity: major
Priority: NOR
Component: screencasting
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 190883
--> https://bugs.kde.org/attachment.cgi?id=190883&action=edit
Example screenshot of how the corruption looks like
SUMMARY
When using OBS Studio’s “Screen Capture (PipeWire)” source to capture an entire
monitor on KDE Plasma Wayland, some fullscreen apps cause background content to
briefly flash around the edges of the captured screen. The issue appears only
when sharing a whole monitor. Capturing a specific app/window instead of the
full monitor avoids the problem. This appears to be related to how the KDE
screencast portal / PipeWire stream handles some fullscreen applications.
I have also previously seen PipeWire/OBS debug output spamming errors that the
buffer contains corrupted data while OBS is running and I'm moving the mouse
around. pw-top is also showing many errors for OBS.
STEPS TO REPRODUCE
1. Use a KDE Plasma Wayland session on Arch Linux
2. Launch OBS Studio and add a "Screen Capture (PipeWire)" source
3. Select an entire monitor when the selector pop-up window asks you
4. Start a stream/recording, fullscreen an app on that monitor (for example
Flatpak Jellyfin Desktop) and play a video
5. Wait a short amount of time usually and observe the preview/stream/recording
6. At least one corrupted frame with whatever is in the background should flash
briefly around the edges of the captured screen
OBSERVED RESULT
When a fullscreen app is visible on the captured monitor, the OBS stream,
recording and preview all randomly flash the background content around the
edges of the screen for a moment. This happens when a whole monitor is selected
for the "Screen Capture (PipeWire)" source. The corruption appears as stale or
incorrect frame regions being composited into the stream (previous frame or
background content leaking at the edges). The issue is reproducible with some
apps like Flatpak Jellyfin Desktop and aur/jellyfin-desktop and I have also
been able to see PipeWire/OBS debug messages previously, such as constant
"debug: [pipewire] buffer contains corrupted data" errors while OBS is running
and I move my mouse around. Capturing a specific app/window instead of the
whole monitor avoids the issue.
Attached to the bug report is an example screenshot of how the "Screen Capture
(PipeWire)" source capture corruption looks like when it happens. The only
visible content should be the one in the center and not the one in the edges
(the desktop in this case).
EXPECTED RESULT
OBS should capture a stable, clean image of the full monitor. Fullscreen apps
should not cause background content to briefly appear around the edges of the
captured display.
SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: 6.6.3
KDE Frameworks Version: 6.24.0
Qt Version: 6.10.2
ADDITIONAL INFORMATION
Environment:
NVIDIA RTX 4080 Super with the latest nvidia-open-dkms drivers
Fully up-to-date Arch Linux
KDE Plasma 6.6.3 on Wayland
OBS Studio 32.1.0 Flatpak
PipeWire 1.6.2
Additional observations:
The issue seems correlated with fullscreen surfaces and does not occur when
capturing individual windows, suggesting a difference in how monitor streams vs
window streams are produced by the screencast portal.
The issue happens with both the Flatpak version of OBS and the native Arch
package.
Capturing a specific app/window instead of the full monitor avoids the issue.
pw-top shows many errors for OBS while it is running.
The issue does not seem to appear when using the third-party Jellyfin client
aur/fladder-bin in fullscreen.
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