If the pic quality is not good then it's not going to get any better if you convert it again. DivX & Xvid, & mpeg are all lossy formats. That means everytime you save or convert into those formats it will throw information away to help it reduce in size. Perhaps the best yo could do is set a target size of the same or slightly larger size but still it's not going to improve quality. Once the quality has gone it's gone forever.