DVD Play back help

start with im using clone dvd and any dvd and a plextor 716a and lg GSA-4163B both with latest firmware updates…and windows 2000 and i use the lg to burn and plextor to read…now heres my problem in my recent movies ive copyed i get the odd ones that pixilate or skip as if it burnt a scratch into the disc is this normal…and if so do u guys have any pointers cuz im sick of having to watch all of the backups to make sure there good or…is there a program that i can run before or after to either test the copy or the orignial…thank u guys so much.

Also using Tdk 16x discs and writing at 16 but have had many flawless burns and i really like tdk media.