Load that AVI in VirtualDubMod and do Stream___Stream List. What type of audio stream is it? Because if you've compressed formats (like AC3) often the encoders cannot decode it ( read http://forums.afterdawn.com/thread_view.cfm/129217 for an explanation of the typical problems). You can: 1) extract a un-compressed WAV form of that stream, and load it as your encoder's 'audio input' (TMPGenc can) or 2) in not, make another AVI having a MP3 stream, instead. See http://forums.afterdawn.com/thread_view.cfm/190445 . If you didn't read my 'sticky' FAQ threads (that I made for you) don't complain..