Poor DVD Quality

Hi,

I created a MP2 video in Premiere Pro CS6 at 1280x768 (4:3)

I import into Encore CS6

I set the DVD to 9 mbps and check the option to render at highest quality...

However, after building the project onto the DVD, then playing it back from the DVD...

The quality is poor (with jaggies etc)

I tried every setting I could find.

Yet, if I create the MP2 video onto a DVD using Corel DVD Factory... the quality is great!!

So, how is it that a small software such as Corel can give better quality then Encore??

Am I missing something?

Thanks