Avidemux as restoration tool

[Blues]

Avidemux is great tool, I use it often. But now I'm facing a challenge. I have a rare old video file. Its audio has annoying 100 Hz noise. I could remove it easily with Audacity. But! The problem is both the audio and video have some chunks missing. Not the same time. Basically, players mange to play it without hiccups. I'm trying to extract audio without losing sync. Avidemux stops when it reaches the first missing audio chunk. All other methods I've tried result in an audio file which goes out of sync after missing pieces.
Is there any hope Avidemux could have added features to do restoration jobs?

[eumagga0x2a]

Does adding an intermediate step of saving with video in copy mode with audio codec set to (L)PCM help?

[Blues]

Unfortunately no. I'm shelving this project for now. Thanks for thinking with me.