| Summary: | Kdenlive, Dragon Player, VLC (and etc.) have no video playback on second/third monitor when Global Scale is set to 2.0 | ||
|---|---|---|---|
| Product: | [Plasma] plasmashell | Reporter: | Frederick Zhang <frederick888> |
| Component: | general | Assignee: | David Edmundson <kde> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | frederick888, kde, plasma-bugs-null |
| Priority: | NOR | ||
| Version First Reported In: | 5.17.1 | ||
| Target Milestone: | 1.0 | ||
| Platform: | Other | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
Using QT_AUTO_SCREEN_SCALE_FACTOR=0 QT_SCALE_FACTOR=0.5 to disable scaling fixes the issue in all mentioned programs. Is this actually an upstream bug from Qt? And btw probably related: https://trac.videolan.org/vlc/ticket/17484 Just checked again and it's been fixed! Not sure if it was caused by nvidia, qt or plasma though. I'm currently running nvidia 440.82, qt 5.14.2 and plasma 5.18.4 with framework 5.68.0. I'm still having the issue on my system with Qt 5.14 Though 5.14.1, maybe 5.14.2 fixes that? Yup I guess that's the reason. Just tried downgrading Qt to 5.14.1 and the issue became reproducible again. |
SUMMARY If Global Scale is set 2.0 (or any value greater than 1.0?), (Qt based?) video players will only play videos on the leftmost monitor. On other monitors it's usually just a black box or the theme background colour in the case of Kdenlive. However, if I drag the window to my leftmost monitor and then move it back, videos will continue playing normally as long as I don't resize the window. My monitor setup is: ┌----------------┐┌--------------------------┐┌------------------┐ | 1920x1080 DP-0 || || 1920x1080 HDMI-0 | └----------------┘| 3840x2160 DP-3 |└------------------┘ | | └--------------------------┘ ...and I use the following xrandr command to arrange them: xrandr --fb 11520x2160 \ --output DP-0 --auto --scale 2.0 --panning 3840x2160+0+0 --pos 0x0 \ --output DP-3 --auto --primary --scale 1.0 --panning 3840x2160+3840+0 --pos 3840x0 \ --output HDMI-0 --auto --scale 2.0 --panning 3840x2160+7680+0 --pos 7680x0 I've tried switching off one of the monitors, disabling X scaling, etc., but the issue can be consistently reproduced when I have Global Scale set to 2.0. On the other hand, if I reset Global Scale to 1.0, no matter which monitors are on, or whether X scaling is enabled or not, video playback always works without any problem. Firefox, Google Chrome, MPlayer, xine, cvlc are not affected, hence I think it's not a codec issue as cvlc and VLC use the same configuration. I've also tested several different video files with different encodings and the results were the same. This is such a strange issue and I'm actually not sure whether it's caused by Plasma, Qt, X or even the Nvidia driver. Sorry if it's the wrong place. STEPS TO REPRODUCE 1. Launch an X session 2. Set Global Scale to 2.0 3. Reboot (or logout/restart plasma) 4. Open a video in Kdenlive/Dragon Player/VLC on a non-leftmost monitor OBSERVED RESULT Kdenlive/Dragon Player/VLC cannot play videos on non-leftmost monitors. Nothing unusual in VLC logs. EXPECTED RESULT Videos play normally on all monitors. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.17.1 KDE Frameworks Version: 5.63.0 Qt Version: 5.13.1 Kernel Version: 5.3.7-arch1-2-ARCH OS Type: 64-bit ADDITIONAL INFORMATION GPU: Nvidia GTX980M Driver: Nvidia proprietary