How do you add new audio to an exisiting DVD?

[aslan]

I have some VCD movies from foreign countries with a lot of different audios. I also have the original DVD movies from another region. So is it possible to first extract the audio from the VCD, then put into the DVD and burn it all with a new copy?

[Baldrick]

Yes. But if they are different length you may get sync problems.

You can extract the audio from the vcd with virtualdub or goldwave. Convert it to ac3 with aften. Add the new audio to the dvd using pgcdemux and muxman, see https://www.videohelp.com/guides/simplistic-guide-for-replacing-dvd-streams-flash-id937#937

[aslan]

There are a lot of guides on the link, I already know how to backup a DVD.
Which one is exactly the one for adding audio to the DVD?

I now have extracted the audio to .ac3.
Do you know how I can edit the sound, for instance cut & join and stuff for the .ac3?