I'm creating a DVD using DVD Architect 5.2, and the Disc Space Used (before preparing) is 4.3 GB, which is about what I want, but after the project is prepared, the Disc Space Used shrinks to 3.4 GB. Is there a setting in Architect I need to change? The DVD still burns and plays, but obviously I would like to maximize the disc space for optimum picture quality.

The original video files used in Vegas 10 are a combination of m2t and AVCHD files shot in hi-def, re-encoded to mpeg2 files to create a standard definition DVD.

DVDA often mis-estimates the final size.

The important issue for quality is that your encode to MPEG2 be done in Vegas or DVDA, not both.

The workflow preferred by many Vegas editors is to encode in Vegas, using a DVDA template for MPEG2. In this situation, you are in control of the bitrate, and should use a bitrate table or calculator to determine what bitrate to encode at. I have a table clipped from Edward Troxel's newsletters (http://jetdv.com) taped to my wall that I refer to. If a mistake is made here with too high a bitrate, DVDA will re-encode to fit on the disk, starting from your already compressed Vegas encode, this can be a severe compromise in quality.

The other workflow is to render an intermediate, not final, out of Vegas. For example, MXF. Then, DVDA will automatically compress when you build your disk.

Be very aware of messages that appear when DVDA is processing the files and building the disk. There is an alert that shows when video or audio will be recompressed, but you have to be aware of what these somewhat cryptic messages mean.

Thanks for the link, I'll look through that message board for help. I am encoding everything in Vegas, and went through a couple of renders before I got the project size under 4.7 GB. In the Properties on DVD Arch, I see that the disc space to be used is approx. 3.4 GB, with no way that I can see to change the outcome (bitrate slider changes the size slightly, but still stays in the 3.4-3.5 range). Maybe I will try re-encoding the main mpeg in Vegas with 2 pass, so if the final disc space used won't change from 3.4 GB, at least I'll know I got the best picture quality with that size.

My favourite bitrate calculator is the one found at http://www.johncline.com/bitcalc110.zip
I've been using it for several years and its never let me down.