Ripping custom dvd, suse 12.1-kde, avidemux

I made a music video tape in college on an analog editor. I lost the original best quality video. I have another, but I found dvd with two videos. I tried k3b, but it gave an error(report saved). I tried handbrake. It worked. The original video was digitized with dvd player. Channel 1&2 have the right audio, hifi has the movie audio. When it was digitized, I got a mix of both. I need to overlay the audio on top of corrupted sound. How do do that with avidemux?

The tape cross-fades into the movie’s dialog for the ending. So, I need to line up the audio and fix the cross-fade. Also, i’v ripped the cd so I have the track.