Are Quicktime and iTunes some how linked for movies?

[filmweaver]

I am now having problems playing SD movies across all my applications, they look pixillated. I never had this problem until I updated to 10.6.4. I didn't update iTunes and was/am afraid to do any more updates.

Anyone else having trouble or does anybody know where I should look for the problem/s?

 

[chrismacguy]

iTunes and QuickTime are very interlinked, in that iTunes is just a pretty library software and UI and store for Quicktime in effect - Quicktime is the framework in OS X that iTunes uses to play movies, so it could be that you need to update iTunes and QuickTime before it will play correctly.

 

[Lokrado]

10.6.4 is known to have decreased graphics performance.