If you love movies as much as I do, you’ve probably heard about MKV (Matroska) containers already. Otherwise, let me tell you a couple of words about them.
First of all, they are generally considered to be superior to any other containers in every aspect. The main reason behind this is that Matroska supports important features compared to any other multimedia container (i.e. variable frame rate and anamorphism which has an important role in video quality).
Another reason is because Matroska can enclose an unlimited number of video, audio, picture or subtitle tracks inside a single MKV file. Because of this, you might want to extract those tracks out of the MKV file. A way to do that is by using a GUI (Graphical User Interface) which I recently discovered, called MKVcleaver.
MKVcleaver requires MKVToolnix, you can get MKVToolnix from here.