Video 2 for using MKVMERGE. The 1st video showed how to use this program in a terminal. This video shows the GUI (Graphical User Interface). You can add together videos, each following the other, making one large video from several that are smaller. You are NOT limited to doing this with MKV files, but can also join together files of other types, for instance, AVI files. You can also add in additional sound tracks and subtitles. The program is lightning fast, faster than using a nonlinear editor of any type. Top recommendations for MKVMERGE!