https://bugs.kde.org/show_bug.cgi?id=517793
Bug ID: 517793
Summary: HDR fullscreen video produces rainbow shimmer/tone
mapping artifacts with "Prefer efficiency" color
accuracy on RX 9070 XT
Classification: Plasma
Product: kwin
Version First 6.6.2
Reported In:
Platform: Arch Linux
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: wayland-generic
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 190786
--> https://bugs.kde.org/attachment.cgi?id=190786&action=edit
This is a picture from my phone since you can't capture this with a screenshot
When HDR is enabled and Color accuracy is set to "Prefer efficiency" in Display
Settings,
fullscreen video playback in Brave browser produces a rainbow
shimmer/iridescent artifact
across the video. The artifact disappears when the mouse is moved (triggering
UI overlay),
cannot be captured by screenshots, and does not occur when HDR is disabled.
Steps to reproduce:
1. Enable HDR on display in System Settings → Display & Monitor
2. Set Color accuracy to "Prefer efficiency"
3. Open Brave browser (running native Wayland via --ozone-platform=wayland)
4. Play any YouTube video and enter fullscreen
Expected result:
Video plays without visual artifacts
Actual result:
Rainbow shimmer/iridescent tone mapping artifact visible over the entire video
frame.
Artifact disappears when mouse is moved or UI overlays appear. Cannot be
captured by
screenshots (confirms it is in the compositor output pipeline, not the video
frame itself).
Workaround:
Setting Color accuracy to "Prefer color accuracy" eliminates the artifact
entirely at no
measurable GPU cost (~0-11% GPU utilization unchanged).
Additional findings:
- Artifact present with VAAPI hardware decode enabled and disabled
- Artifact present with both 8-bit and 10-bit color depth settings
- Artifact only occurs in fullscreen, not windowed video playback
- Brave confirmed running as native Wayland client (--ozone-platform=wayland in
gpu-process)
- Video stream color space: BT709, LIMITED range (standard SDR content)
Note: Another RX 9070 XT user reported the opposite behavior in
https://discuss.kde.org/t/fix-rx-9070-9070xt-on-kde-plasma-wayland-distortion-and-flickering/32866
where "Prefer efficiency" fixed their distortion issue. This suggests the
efficiency
pipeline has multiple distinct failure modes on RDNA 4 hardware.
System:
KWin: 6.6.2
Mesa: 26.0.2
Kernel: 6.19.8-arch1-1
GPU: AMD Radeon RX 9070 XT (radeonsi, gfx1201, ACO)
Display: LG Ultragear+ 3440x1440 @ 239.99Hz, HDR enabled, Adaptive Sync
disabled
Session: Wayland
Qt: 6.10.2
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