For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ykoba:multimedia/openSUSE_Tumbleweed/home:ykoba:multimedia.repo
zypper refresh
zypper install qmmp
For openSUSE Leap 15.1 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ykoba:multimedia/openSUSE_Leap_15.1/home:ykoba:multimedia.repo
zypper refresh
zypper install qmmp
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ykoba:multimedia/15.5/home:ykoba:multimedia.repo
zypper refresh
zypper install qmmp
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ykoba:multimedia/15.4/home:ykoba:multimedia.repo
zypper refresh
zypper install qmmp