> I'm using Ubuntu (Lucid) and have noticed that if I run MAME with "-video opengl", I > get a half second audio delay. If I don't specify this then the audio is in sync.
Here's what fixes a cornucopia of audio problems on Ubuntu for most people:
sudo apt-get install libsdl1.2debian-pulseaudio
Are you sure it's the audio that's delayed? -video opengl if it hits Mesa fallback could easily delay the video relative to the audio. -mt can help in that instance if you have at least 2 CPUs/cores.