My 4 years old son was watching an old movie (burn around august 2003) when he called me because of some pixelation and skipping. There's some tiny scratches on the disk. After I "SkipDr", it still show pixelation and skipping. Then I re-backup the movie (no read error--scratches not deep enough), and burn it again. The new backup is great.
Here is the old backup scan. It was burn @2.4x with my old HP200i. The glitches was from the middle of the movie toward the end. Seems related to the PIF errors.