I want to render some mpeg2 fiels streight out of AE6.5 but when I choose one of the presets such as NTSC DVD 4:3, DVD Architects wants to recompress the video as it is not complients.
Go to the Explorer window in DVD Architect, right-click on the file you rendered, and choose Properties. Copy what's there and paste it here so we can see exactly what kind of file After Affects is outputting. A template called NTSC DVD should be giving you a proper file, but who knows.
Make sure that the settings of that file match any settings in the DVDA project (File -> Properties) -- same aspect ratio, same resolution.
Oh, and a quick question: The video in question, is it being used as as a movie or as a menu background? Menu backgrounds will always be recompressed if you added anything (text or images) on top of them in order to make the menu into a complete video object.