how do you change/replace the audio in a movie file to another audio in a movie file

Can anyone help me with this question right how do you change the audio in a movie file to another audio in a movie file right i have got a movie called Echoes of a Summer 1976 and it has
been taped off tv cos this movie is only available on tv to watch this movie has never come out on dvd or vhs so it is a rare movie and the movie is very bad quality but the audio is in English right i found the same movie as a web.dl and the quality is perfect but this one of the movie they don’t speak English it has been dub in another language so i thought is it possible to use the audio in the first movie which is English the bad quality movie and use that with the other movie which is great quality which is in another language so the one with the perfect quality web.dl movie is it possible to add the audio from the first movie to the other movie which is perfect quality can i add the audio from the first movie to the second movie is it possible to do this or not so is there any software’s that will do this
if anyone can help me with this that would be great
Answer #1
mkvmerge
Answer #2
Have a look around Videohelp..
http://www.videohelp.com/search?q=replace+an+adio+track+with+another