Hi expert,

 I have installed the software of VLC media player.  it was sometimes 
without audio but a clear video.   when I reboot the system then audio
may run well but sometimes it still mute.  this problem also to the audio
software player Rhythmbox Music player.

  when I test the soundcard by system-config-soundcard. the test sound
also sometimes run well. it is so strange. may it due to the soundcard
driver??
 could anyone can give me a help.

  thanks in advance!

  best regards,
     fengchu