Dear forum members, I am going to download Avidemux, but am presented with three choices: GTK X11 GTK Quartz QT4 I have no idea what these mean, other than some type of program interface that allows non-native Mac applications to run on the Mac. Any thoughts on which one I should be choosing? Since video encoding is a processing intensive task, choosing the fastest and most efficient one is important. Thank you! JC P.S. My aim is to join multiple FLV files into a single one. So any alternative programs you can suggest would be greatly appreciated.