About this backend ------------------ This backend is not a real Phonon4Qt5 backend. Therefore Phonon4Qt5 based (i.e. most KF5 and some Qt5) applications will produce no audio or video output. Typically, this is an undesirable configuration which you might have gotten to unintentionally. However, `phonon4qt5-backend-null' might be useful if you are not interested in multimedia and you don't want to install a number of pretty heavy packages which real backends typically depend on. If you wish to restore full Phonon4Qt5 multimedia capabilities, install a real Phonon4Qt5 backend with your favourite package manager. The recommended backend is `${recommended4qt5_backend}' but you may choose any other package which provides the `phonon4qt5-backend' virtual package. Use whatever works best with your system setup. Phonon4Qt5 backend package names typically start with 'phonon4qt5-backend-' string by convention. Have a look at the packages suggested by the `phonon4qt5' package as well.