Hello,
Leap 15.4 provides qmmp 1.5.1 version that works fine.
Leap 15.5 provides Qt6 based qmmp 2.1.2 version.
This version is practically unusable, because most input plugins are missing, i.e. it cannnot play mp3 or aac streams.
Plugins like libmpeg, libffmpeg, libflac etc. are present in Leap 15.4 rpm packages but not in Leap 15.5 packages.
Plugins are missing from qmmp 2.1.2 build because they require newer version of dependency packages.
Packman version for Leap 15.5 is not available.
Similar issue is discussed on upstream butracker, in Packman context
https://sourceforge.net/p/qmmp-dev/tickets/1123/
Essentially, they recommend to use qmmp 1.6 branch for distros without bleeding edge versions of dependency packages.
Personally, I resolved this by recompiling older version.
I took source rpm from Leap 15.4 and rebuilt it with Leap 15.5 toolchain.
Resulting binaries work without issues.
In my opinion, qmmp distributed in Leap 15.5 backport repository should be based on 1.6 branch.
Qmmp Qt5 based branch 1.6 is still actively maintained and will be in forseeable future, so Leap varsion should be based on this branch.
As an added bonus, it will not reqire Qt6 libraries, currently this is the only app using them.
Regards