Binary package “phonon-backend-null” in ubuntu bionic

multimedia framework from KDE - null back-end (no real back-end)

 Phonon is the Qt 4 multimedia API, which provides a task-oriented abstraction
 layer for capturing, mixing, processing, and playing audio and video content.
 .
 This package does not provide any real Phonon back-end. It can be used to
 disable Phonon audio/video capabilities. Please note that Phonon behavior
 with this package installed has not been well tested.