It depends on what you mean by distorted:
-if you are experiencing the distortion when you try to do move a step, then it's because your PC is too slow or you need more RAM
-if the distortion is the same and at the same point everu time you play the vid, then the image is a little corrupt.

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iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

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