With Moboplayer, the MP4 video I downloaded from youtube lags. With every other type of player, it completely refuses to load. It also refuses to load with hardware decoding, if that makes any difference.
Not sure about that, sorry. My experience with conversion of videos has never been good. They always seem to have to audio off and that really really bugs me! I'm sure someone knows.
I here about dvd catalyst all the time from people here. Used to convert dvd movies to mp4.