We have same situation at first, some of my converted video makes the game hang after one custom video was played (can't get the next vid. to start and sometimes you can't even use control-alt-del).
After several try, i was lucky i have made two videos work-but right now, i wasn't really even sure what made it played, but it played anyway-as well as continuing to the next vid. I am looking at the frame-rate, file size, duration, and the total number of frames my custom video has and that of the original. But until now i still can't get a constant result. I'll try to look at those files again, see if what i can do.
In case you can figure out the whole thing, just share the rundown here.