I think the problem comes when you try and go from an HD progressive format to an SD interlaced format. In my opinion if you shoot HD progressive and then go straight to MPEG-2 (for DVD) I think it might stay progressive so you won't have any major issues. If you tried to go from and HD timeline to DV (720x480 interlaced) then you'd have a problem using Compressor. At least that's been my experience.

Still trying to figure this all out. (at least I feel like I'm making some good headway!)

Seems logical to me - previously we've done the 'edit HD > then export to DVCPRO HD 720p then go to Compressor' route - but if we are making SD DVDs that will be seen on computer monitors or LCD screens, not CRT, there's no deinterlacing issue so can just go straight to Compressor, to a progressive mpeg2 setting, I guess. What do others think? We've yet to actually test this.

How can we accurately tell what monitor people are going to watch a DVD on?

In the case of the DVD we're about to make, by asking the client who'll be using it in accompanied training situations, in quality hotels - so anticipate LCDs.

Makes sense, Mark.

I was thinking of public use (which is our case).
It's a dilemma because some will have one, and some the other - but most probably couldn't tell you which they have!

I "think" this is a true statement:

"Watching the DVD on a tube (CRT) television = produce interlaced DVD

Otherwise, you're safe producing a progressive DVD. The only advantage with interlaced is smoother motion. For example, if you have a text crawl at the bottom of the screen (tough to do in progressive format)

The only question I have is about those progressive DVD players that came out a while back. Remember those? Does that mean that the older DVD players couldn't display progressive video? What about computer's? (Apple Quicktime and Windows Media Player) Can computers display progressive DVD's? I'm guessing they can.

Yes they can.

Progressive is the 'natural' state of things.

Interlacing is a clever, interesting but redundant workaround stemming from a technical limitation of early Cathode Ray technology. In the world of Plasma, LCD, projection, computers and mobile technology, it is anathema and an abomination. It is redundant and unhelpful on all but old cathode ray TV sets.

What you appear to gain in motion, you lose in resolution. Getting rid of interlacing robs you of 25% of your vertical resolution in a best-case scenario, or if you leave it until display time, it's 50% on a lot of cheaper displays.

How 50i and 60i got into the nomenclature of HD is a disappointing victory of marketing over common sense, as nobody I've challenged (including Sony, Panasonic et al) can tell me of a native HD display that uses native interlacing.

So it sounds like progressive is the way to go for DVD (and web for that matter).

My issue is that the darn local broadcasters are still only accepting commercials in DV format, so that means interlaced. (good think I've figured out progressive to interlaced AfterEffects work around that looks decent)

Progressive renders at almost twice the speed of interlaced. (at least in AfterEffects)