Hi!
Long time ago I tried to get the audio track from a VHS tape in sync with a DVD - a really painful job!
Now I finished writing a tool for doing this - "transplanting" a desired language track from a "bad" into a HD movie.

Main concept is to "tack" characteristic audio patterns with "syncpoints" together.
The imported audio is then "rubberbanded" (stretched) between those syncpoints.
Workflow should be intuitive - please grab into the included "readme" for further explanations.

Current restrictions:
The imported track is always converted to 16bit stereo, resampled & recoded to ac3 (or aac?).
Output is always a .mkv
Optional text subtitle adding is provided. Some fundamental edit fuctions for .srt format only.

I couldn't manage to create a .deb package - only a AppImage (created Ubuntu22.04) and a zip folder Win10_64 (should run standalone) is available.
Not tested for other os versions.

FFmpeg installed & inside execution path is required.

Binaries for Win10_64 and Linux-x86_64 & readme are here:
https://github.com/marsoupilamigit/RubberDub