SUMMARY I'm not sure if this issue is related to kwin or another thing on my system. Video playback is choppy like the gear animation of glxgears observed in the following video. https://youtu.be/2JvS5PtY2MQ On X11 playback is better but not perfect despite the framerate is 59-60 fps there. STEPS TO REPRODUCE 1. use Wayland session 2. play a video with VLC or mpv player 3. OBSERVED RESULT choppy video playback EXPECTED RESULT fluid video playback SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.24.90 KDE Frameworks Version: 5.94.0 Qt Version: 5.15.4 Kernel Version: 5.17.9-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 2 × Intel® Celeron® CPU G1820 @ 2.70GHz Memory: 7,6 GiB of RAM Graphics Processor: Mesa Intel® HD Graphics
Is this regression compared to 5.24?
No. It's an old issue.
Huh, I see. Regardless, it's odd that even not resource demanding apps such as glxgears stutter. Does changing latency policy make things any better?
(In reply to Vlad Zahorodnii from comment #3) > Huh, I see. Regardless, it's odd that even not resource demanding apps such > as glxgears stutter. Does changing latency policy make things any better? No.
I can't reproduce the stuttering with glxgears using another user account. Video playback is also better, but it is still stuttering a bit with certain videos even on X11. Operating System: Arch Linux KDE Plasma Version: 5.25.4 KDE Frameworks Version: 5.96.0 Qt Version: 5.15.5 Kernel Version: 5.19.0-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 2 × Intel® Celeron® CPU G1820 @ 2.70GHz Memory: 7,6 GiB of RAM Graphics Processor: Mesa Intel® HD Graphics
I can repro this but only if I set scaling for my screen to something > 100%, like say 120%. Playback of regular HD videos stutters greatly, MPV reports many dropped frames and the new FPS tool shows 30fps instead of 60. My monitor is a TCL 43" HDR TV, 3840x2160@60Hz. Running wayland session, kwin from git master, MPV from git master as well. MPV reports (shift+i) really weird scaled resolution, like 6104x2880, not sure where that comes from. When I switch back to 100% scaling, all works as expected and the FPS tool show 60fps as well as MPV.
I should add, using AmdGPU driver, RX560, I've tried with mpv --no-config and mpv with my normal config, which is vulkan and wayland: [code] ... gpu-api=vulkan gpu-context=waylandvk vo=gpu-next ao=pipewire vulkan-async-compute=yes af=lavfi=[loudnorm=I=-16:TP=-3:LRA=4] audio-channels=2 hwdec=auto-copy ... [/code]
bug 449951 is related to display scale.
Putting aside that in no way, shape or connotation in the dictionary glxgears could be considered as "video playback", bug 449951 was supposedly addressed in the KDE 6 beta.
Yep, appears fixed in 5.27 (tumbleweed) and for sure is fixed in 6.x.
Great!
This bug persists on my system. There is a considerable lag when the credits slide in the end of a movie, for example. On X11, the lag is less noticeable, but it is present too. I can reproduce with a new user account too. I can reproduce with VLC player, mpv, mplayer and gstreamer-based players like Totem and Glide. va-api is working: $ vainfo Trying display: wayland vainfo: VA-API version: 1.20 (libva 2.20.1) vainfo: Driver version: Intel i965 driver for Intel(R) Haswell Desktop - 2.4.1 vainfo: Supported profile and entrypoints VAProfileMPEG2Simple : VAEntrypointVLD VAProfileMPEG2Simple : VAEntrypointEncSlice VAProfileMPEG2Main : VAEntrypointVLD VAProfileMPEG2Main : VAEntrypointEncSlice VAProfileH264ConstrainedBaseline: VAEntrypointVLD VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice VAProfileH264Main : VAEntrypointVLD VAProfileH264Main : VAEntrypointEncSlice VAProfileH264High : VAEntrypointVLD VAProfileH264High : VAEntrypointEncSlice VAProfileH264MultiviewHigh : VAEntrypointVLD VAProfileH264MultiviewHigh : VAEntrypointEncSlice VAProfileH264StereoHigh : VAEntrypointVLD VAProfileH264StereoHigh : VAEntrypointEncSlice VAProfileVC1Simple : VAEntrypointVLD VAProfileVC1Main : VAEntrypointVLD VAProfileVC1Advanced : VAEntrypointVLD VAProfileNone : VAEntrypointVideoProc VAProfileJPEGBaseline : VAEntrypointVLD I have Windows 10 installed on the same computer and the mentioned lag does not exist when playing the same videos on it. Operating System: Arch Linux KDE Plasma Version: 5.93.0 KDE Frameworks Version: 5.249.0 Qt Version: 6.7.0 Kernel Version: 6.7.5-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 4 × Intel® Core™ i5-4670K CPU @ 3.40GHz Memory: 15,5 GiB of RAM Graphics Processor: Mesa Intel® HD Graphics 4600 Manufacturer: Gigabyte Technology Co., Ltd. Product Name: B85M-D3PH
Git commit 40a9f08dd34948264ba5b533da5373a0a51ad3f1 by Xaver Hugl. Committed on 24/05/2024 at 15:32. Pushed by zamundaaa into branch 'master'. backends/drm: allow up to two composited frames to be pending at the same time This should improve responsiveness on setups where rendering each frame takes longer than the refresh cycle of the display. Related: bug 452119 M +4 -0 src/backends/drm/drm_output.cpp https://invent.kde.org/plasma/kwin/-/commit/40a9f08dd34948264ba5b533da5373a0a51ad3f1
Git commit 192232e8d1736307f93792ea77de80e61f746bd3 by Xaver Hugl. Committed on 24/05/2024 at 15:59. Pushed by zamundaaa into branch 'Plasma/6.1'. backends/drm: allow up to two composited frames to be pending at the same time This should improve responsiveness on setups where rendering each frame takes longer than the refresh cycle of the display. Related: bug 452119 M +4 -0 src/backends/drm/drm_output.cpp https://invent.kde.org/plasma/kwin/-/commit/192232e8d1736307f93792ea77de80e61f746bd3
Beyond keeping compositing responsive, we can't fix video playback issues. If they're still visible with 6.1, please check again if the problem is actually triggered by compositing, or if it's the video player not keeping up with the screen