it took me hours to figure out why amarok (2) didn’t want to give a damn tone out of its entrails on my jaunty system. checked if phonon has an appropriate backend installed (xine and gstreamer available, tried all combinations), switched around the settings in KDE’s control panel “systemsettings” (i’m a gnome user, so i had to install this first). strangely enough, the latter played the test-sound without any problems, so it seemed to be impossible to be a general sound-server problem.
what else? well, the other KDE sound app named “juk” didn’t play mp3s as well – it just skipped any song and proceeded to the next one, until the end of the playlist was reached (just as amarok did). now i figured out why: they just had no possibility to decode them, since the appropriate xine-lib was missing! a simple command fixed the issue:
sudo aptitude install libxine1-ffmpeg
as far as i can see this is indeed a deficiency in debians package format, since this kind of dependency cannot be mapped. speaking in human words, this means: if you install amarok and want to use it with phonon-backend-xine and want to play MP3s, then you have to install libxine1-ffmpeg