I cannot use VLC to playback AC3 Divxs/Xvids. Stereo works OK but no SPDIF AC3. The only setting I can see that relates to this is in Audio Device, A/52 over SPDIF (not sure what A/52 refers to). If I activate this it sends the information to my digital amplifier as expected but the sound is unrecognisable. The AC3 LED on my amp flickers instead of showing a solid light. Any clues?