This is probably a simple question but I'm curious. In Vegas is it better to PRE-render a time-line at the best quality before rendering out as a MPG-2 or is there really no difference from straight rendering to MPG-2 from the time-line?

I see no reason to do a pre-render so I render direct to MPEG-2 from the timeline.
If the video is over 80 min., I'll tweak the bitrate to get the most out of it.

It depends on which format you use for your pre-renders. If it's DV, then there is going to be a colorspace conversion issue.

DV is 4:1:1 and DVD MPEG2 is 4:2:0, if you render MPEG2 from DV, you end up with 4:1:0. 4:1:0 means that you will only have 12.5% of your original DV chroma resolution left on the DVD. Vegas generates all media and titles at full 4:4:4, so if you render directly from the timeline, all generated media and titles will end up at 4:2:0 on the DVD, although DV media will still take the 4:1:0 hit.

That's the long answer, the short answer is render directly from the timeline.

John

No reason to do a pre-render.

Thanks to all for the information. The color space conversion makes particular sense.