I'm trying this software for the first time with a 7 min. video shot with a Nikon camera. After joining several clips with avidemux it has been converted from mov to mp4. When trying to clip out some blurred video, this software constantly locks up with a not responding message for several minutes. The couple of times I managed to start the video, I get sound, but no video or frames. I am using the evaluation version and would happily buy it if it actually works. I've wasted a couple of hrs. without any luck at all. I've looked at the simple guide, but since I get no video, I can't get started. Am I missing something or doing something wrong? All I have managed to do so far is open the file and even that takes a while for only a 7 min. video.