Nice reply, many thanks
MKVExtract for Extracting Audio from a .MKV Movie
MKVToolnix for Adding Audio to a .MKV Movie
Yamb for Both Extracting n Adding Audio to a .MP4 Movie
AviDemux for Both Adding n Extracting Audio from a .AVI Movie
If any query then don't hesitate n go for it !
One thing you will need to do is to make sure the additional audio track is the same length(time), and also ensure it is the same FPS as the movie audio you are adding it to otherwise you will have synchronization problems that can be a real pain to fix.
hi everyone can someone help me in finding software to take out an audio file from a movie and add another thanks mr866