6 months ago I switched to Kitty for terminal emulation [1]. So far there’s only been one thing that I couldn’t effectively do with Kitty that I did with Konsole in the past, that is watching a music video in 1/4 of the screen while using the rest for terminals. I could setup multiple Kitty windows taking up the rest of the screen but I wanted to keep using a single Kitty with multiple terminals and just have mpv go over one of them. Kitty supports it’s own graphical interface so “mpv –vo=kitty” works but took 6* the CPU power in my tests which isn’t good for a laptop.
For X11 there’s a –ontop option for mpv that does what you expect, but that doesn’t work on Wayland. Not working is mostly Wayland’s fault as there is a long tail of less commonly used graphical operations that work in X11 but aren’t yet implemented in Wayland. I have filed a Debian bug report about this, the mpv man page should note that it’s only going to work on X11 on Linux.
I have discovered a solution to that, in the KDE settings there’s a “Window Rules” section, I created an entry for “Window class” exactly matching “mpv” and then added a rule “Keep above other windows” and set it for “force” and “yes”.
After that I can just resize mpv to occlude just one terminal and keep using the rest. Also one noteworthy thing with this is that it makes mpv go on top of the KDE taskbar, which can be a feature.