I have an external DVD drive an HP and I have had it for a while. I've been burning DVDs successfuly for a little while but occasionally and for some reason more recently I have had trouble with the the DVDs I burn turning up choppy in the DVD player toward the end of the movies and I can't seem to figure out why. They work cleanly when I put them back in the burner that burnt them and watch them on the computer. Any suggestions. P.S. my firmware is up to date.