Thanks, I will look into that, MeGui does sound interesting. In the end, after a few trials and experiments, I did end up preserving the 5.1 audio and it worked out well. I just didn’t realize at first that you had to go into Audacity settings and change a setting to allow you to use a custom mix output. Before that, it downmixed everything into 2-channel audio. After changing that setting, it preserved everything, even the oddball four-channel mixes some of the SG-1 discs used.
Oh yeah, I remember that strange sound setup on stargate, I think it was the first couple of episodes (DVD 1 and possibly two) of season 2 of SG-1.