I need some help with building (better word should be rebuilding) DVP workflow.
My good friend makes wedding videos, as same as photographs it. To get more speed from processing, I rebuilt it's video processing system which was very old and slow (Pentium 4 HT processor with 2GB memory and so on...).

The workflow was something like that:

Sony camera >> some old Canopus video decoder (through FireWire port) to import videos from camera >> Adobe Premiere 7.0 for processing the video >> Back to Canopus for Digital to Analog conversion in real time >> Philips stand-alone DVD player to record it to DVD-Video (MPEG-2).
The video quality in DVD-Video after processing was quite good.

Now I built new computer for him (Windows 7 64bit, Dual Core CPU...) and changed Adobe Premiere 7.0 to CS3. The problem is with Canopus DV card which is not supported in Windows 7, so I have to avoid it in some way.

So now I get the video from camera, make a project in Adobe Premiere, and then I export it to MPEG2 video file using Adobe Media Encoder. The video quality is fine. But I don't know how to write it to DVD-Video using computer's DVD writer.

I tried several different programs, and they all make DVD-video quality much worse (seems like graphic artifacts or too low resolution) than MPEG2 video file which I get from Adobe Media Encoder. The best program I found was TMPGEnc DVD Author but it's also not perfect speaking about video quality.

Is it video codec problem, or something other? How to write good quality MPEG-2 file with DVD-burner to DVD-Video disc, to get the same - good video quality? Any software recommendations?