I don't know when it happened but my sound and audiovisual files have become a problem to play.
Trying to play flac with Amarok gives the error message:
Audio output unavailable; the device is busy.
Totem Movie Player plays the first second of flv and wma files, then stops, saying:
Invalid argument: failed to connect to stream
VLC is working fine and the Applian free FLV player is working in Wine.
I don't normally use Rhythmbox but that won't play anything either.