SUMMARY 4K videos on X11 play perfectly fluid, Full HD videos on Wayland play perfectly well too, but 4K videos on Wayland get choppy, especially when maximized/fullscreen. Forcing hwdec with vaapi improves this a bit, but it's still choppy. This was tested on both Plasma Wayland and GNOME Wayland. STEPS TO REPRODUCE 1. Download Big Buck Bunny in Full HD and 4K (http://bbb3d.renderfarming.net/download.html) 2. Compare how fluidly Full HD plays on Haruna compared to 4K 3. Compare how fluidly 4K plays on Haruna compared to VLC or MPV SOFTWARE/OS VERSIONS Operating System: openSUSE Tumbleweed 20210904 KDE Plasma Version: 5.22.5 KDE Frameworks Version: 5.85.0 Qt Version: 5.15.2 Kernel Version: 5.13.13-1-default (64-bit) Graphics Platform: Wayland Processors: 4 × Intel® Core™ i7-5500U CPU @ 2.40GHz Memory: 7.7 GiB of RAM Graphics Processor: Mesa Intel® HD Graphics 5500 ADDITIONAL INFORMATION # FFMPEG ffmpeg version 4.4 Copyright (c) 2000-2021 the FFmpeg developers built with gcc 11 (SUSE Linux) configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --incdir=/usr/include/ffmpeg --extra-cflags='-O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -Werror=return-type -flto=auto -ffat-lto-objects -g' --optflags='-O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -Werror=return-type -flto=auto -ffat-lto-objects -g' --disable-htmlpages --enable-pic --disable-stripping --enable-shared --disable-static --enable-gpl --enable-version3 --enable-libsmbclient --disable-openssl --enable-avresample --enable-gnutls --enable-ladspa --enable-vulkan --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcelt --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libdc1394 --enable-libdrm --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librav1e --enable-librubberband --enable-libsvtav1 --enable-libsoxr --enable-libspeex --enable-libssh --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libwebp --enable-libxml2 --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lto --enable-lv2 --enable-libmfx --enable-vaapi --enable-vdpau --enable-version3 --enable-libfdk-aac-dlopen --enable-nonfree --enable-libvo-amrwbenc --enable-libx264 --enable-libx265 --enable-librtmp --enable-libxvid libavutil 56. 70.100 / 56. 70.100 libavcodec 58.134.100 / 58.134.100 libavformat 58. 76.100 / 58. 76.100 libavdevice 58. 13.100 / 58. 13.100 libavfilter 7.110.100 / 7.110.100 libavresample 4. 0. 0 / 4. 0. 0 libswscale 5. 9.100 / 5. 9.100 libswresample 3. 9.100 / 3. 9.100 libpostproc 55. 9.100 / 55. 9.100 # libmpv 0.33.1+git.20210630T163736.f2afae55e9-1.2
I have an Nvidia GPU so Wayland is very unstable for me, lots of flickering and windows turning to black rectangles. Playback was bad for me too with Haruna. VLC played it smoothly, mpv only gave me a black window with audio and SMPlayer wouldn't open the file at all. So I couldn't compare with another mpv based player. Setting the scaling back to 100% improved playback a little. The above is for my 2560x1440 screen, on my 1920x1080 it was better, but still choppy.
I have been testing this on an older and lower end PC and it doesn't look like something I can solve. Here's a bug on mpv's issue tracker I opened on the subject, but so far got no response https://github.com/mpv-player/mpv/issues/9417 I also asked on kde mailing list, but got nothing helpful.
Hmm, after taking a look at the VLC comment https://github.com/mpv-player/mpv/issues/9417#issuecomment-963132782 it seemed to me like it might be a Qt issue, and I found this: Suboptimal playback performance with 4K@60fps when using QML MediaPlayer + VAAPI HW decoding https://bugreports.qt.io/browse/QTBUG-79301 , closed without any comments. It's awfully similar, but I'm not sure it's relevant, Haruna doesn't seem to use QtMultimedia/MediaPlayer.
Try with the latest changes. If you can't compile it yourself use the flatpak from the kde remote https://userbase.kde.org/Tutorials/Flatpak#Nightly_KDE_Apps