right so it starts to glitch at the end of the movies? I suspect that the number of errors is building up until near the end of the disk it becomes so large it causes data corruption. So i would ask you to post a k-probe scan but why waste time when thats probably the problem! So go get an updated firmware for your drive, go to
find your drive and flash your drive with the lastest firmware, if you haven't got a clue what i'm talking about, tell me and i'll explain. Now what dvds are you using? And what kind (dvd+r's or -r's)? I have a lite-on drive, they have a reputation for not liking dvd-r's a lot, so get yourself some good quality +r's (i use ritek r02's, aka datasafe). I've had this same problem in the past with my lite-on drive, this is how to solve it. Also if you do use +r's then make sure you change the bitsetting, you can find a tool for doing that on the link above somewhere. It just basically makes dvd players think that your +r burned disc is actually a dvd-rom, makes it more compatible.