How to convert avi to avi with multiple channels

[kultakala]

Hi everybody,

At first i have to say that english is not my first language so maybe i explain something a little bit wrong
And also this is the reason why searching the forum didnt bring me to a solution yet.
So, i will ask explicitly if someone has a tip for me.
I have a hardware media player and a few avi files which the device cant play.
The files are avi with different codecs in it and i dont know exactly why they dont play.
But i managed to convert them to avi´s again with xvid and mp3 codec so that my player can play them. For converting i used virtualdub.
But some of the files have multiple channels (?) in it.
I mean they have for example english and german in two channels.
When converting the files i get a working avi, but with only one channel.
Mostly that is the german channel but i would like to have the english one (to practise the language) or better both channels.
What tool do i need to do this ?
And how ?

Would be great if anybody can help me!

Thank!

kultakala

[Cornucopia]

Demux first with AVIMux-Gui, then convert each separately, then Re-Mux with AVIMux-Gui.