MPEG 2 Conversion Looks Nasty

Question

I have to get a DVD prepared for replication and I've been testing the MPEG2 conversion with a 5 minute clip from the movie putting it through Quicktime conversion in final cut pro HD. I set the bit rate to 6.5kbps and 7.5kpbs (as I figured this would be good for an 8.5Gb dual layer replication) and then set it to make 2 passes before converting.
I then compiled it in Studio V2, burned it to a Maxell DVD-R disc and put it into a brand new Phillips DVD player hooked up to a domestic TV set. The quality was acceptable, but I was still seeing a lot of pixelation (especially in the right hand corner for some reason). It just did not compare to any similar video from similar DVDs I've compared it to.
Am I setting too low a bit rate, or just using the wrong conversion software??? Can I set a higher bit rate as my movie is 2 hours 10 minutes long and I'm going to replicate to a dual layer 8.5gb disc.
Should I just put my video through a P.C mpeg2 convertor instead, because I don't even know if Quicktime is any good???

Answer 1

Yes, I do have a deadline unfortunately, which is why speed is almost definitely an option when it comes to rendering.
I used three different processes to create MPEG2 from a 10 minute clip of my Final Cut Pro sequence. I'm using FCP 4 with the HD upgrade (I think that's correct!)
1) Compressor - I set the bit stream between 7.5 and 8kbps on One Pass. It took 70 minutes to render 10 minutes. I compiled it in DVDSP with an AIFF sountrack (as the sound problems are secondary at the moment) and burned to a DVD-R Maxell disk. The results on a stand alone DVD player through a domestic set were superb. Couldn't notice any artifacts, or pixelation. However, for some reason my sound started to drift out of synch and got gradually worse through the 10 minutes. No idea why. The sound was processed through compressor, but maybe the error is the player or DVDSP.
2) Quicktime Conversion MPEG2 - I set the target bit rate at 7.5kbps, motion best and one pass. It took only 30 minutes to render the 10 minutes. Compiled in studio. AIFF sound compiled at the same time as the picture. Again, the results were superb. No artifacts, no pixelation. I think there was a very, very slight jitter compared to the Compressor version, but this could have been me imagining it, but either way, it had absolutely no effect on the viewing or the quality. Sound remained perfectly in synch.
3) DV Stream - There were no advanced settings so I assume this is just a quick way of outputting DVD content, althought the render time was just as long as the Quicktime Conversion. Not a particularly good output though, very grainy, but certainly watchable.
I didn't compress any footage in DVDSP because the manual seemed to make it clear that the codec was exactly the same as the QT MPEG2 Codec in Final Cut. Also couldn't find how to import an FCP sequence into it.
Anyway, I'm happy with the results that QT achieves inside Final Cut Pro, but it's the ease of use and the speed of rendering which seals it for me. If I had a broadcast monitor I bet I could find bigger differences, but this is good enough for me. Perhaps the VBR was the problem all along because with all my swinging camera moves and crash zooms, I didn't see any picture loss using the fixed one pass method. Just hope that 7.5kbps is not too high for a replicated DVD with a 130 minute running time.
I'll get onto compressing the sound properly now, so will follow the advice given and use Compressor to do it.
Thanks to everyone though, as you have helped me a million and the support makes me feel like I'm not stressing all alone.