I noticed, that the gstreamer-Backend does not play any sound. gstreamer needs a running glib-eventloop, for that qt needs support for glib. Since I enabled the glib-USE-Flag, gstreamer-Backend works as expected. Reproducible: Always
I updated the title, as this problem also applies to <phonon-4.4. I don't know how pulseaudio-backend is affected, but i could imagine it also needs glib-events dispatched by Qt, as phonon needs pulseaudio built with glib-support enabled.
well i hope this problem get solved soon i can confirm this problem too
Fixed for phonon-4.4.4