Video encoding problem!!!?

if we encode any video in formats such as dat vob avi... to mpg1 or mpg2 after some time the audio and video gets disturbed and both will not coinside with each other. please suggest me any of the best encoders that can fix this problem. suggest me if i have to do some thing with the bitrates. i have used imtoo, xilisoft, 007 dvd, etc but the audio go first to the video. even suggest me some good movie cutters that can cut keeping in mind the above problem.