With KDE
Have you opened Computer, Administrator Settings, Hardware, Sound, and used the Edit button to re-configure your sound? You may then use Other on the same page to Play Test Sound and if necessary to use Volume to enter and adjust the settings for sound. That and adjustments in KMix could help with the problem.
Did you install vlc using the openSUSE link here? It solves many problems with dependencies.
http://www.videolan.org/vlc/