My HTPC: Blu-ray great, DVD rubbish

[Stiggy]

An odd problem with my system which I hope someone can help me fix.

I'm using a Dell i5 PC with ATI HD 5450 graphics, and I can watch recorded HD Freeview/freesat and Blu-ray with no problems using Windows 7 media Center and TMT3.

However, when watching ordinary DVDs or 'bonus features' on Blu-ray I get tearing in the lower 10% of the screen, and often have audio sync problems.

I'm not using any 3rd party codecs.

Any ideas on how to fix this?

 

[Stiggy]

Should I be looking to change the default codecs for MPEG2?

 

[jameson_uk]

What refresh rate are you watching bluray extras at?

Standard DVDs are odd though as should be using the same as live TV (or have you changed video codecs?)