Bob, thanks!
I think I'd leave the old stuff as it was, edit it in it's native format and composite it into the HD at it's original resolution i.e. not upscale it

I have come to the same conclusion too, for most of the original 4:3 footages. Surprisingly though, some of the 4.3 are from alpine skiing, shot by a steady hand, and they look very well upscaled, in fact, I like them more than the original. Using the track motion I can improve the composition too.

With SD you mean DVD? And HD=Bluray?

I also came across something I really do not understand. I am used to see the lines from interlaced video in preview in Vegas. Here it goes: I make a project 1920x1080 and upscale the 4.3 videos, overlap, rotate, scale and all that kind of stuff. I render this out to a 960x540 AVI, for test purposes. When I add this AVI to another 1920x1080, I do not see the "interlaced lines" anynore, instead I see ghost images, like two complete 50i frames joined.
When rendering to MPEG and then burning a DVD, it looks normal on the TV! No ghosts. I was a little puzzled by this, but admit I have a lot to learn.

ingvarai

"With SD you mean DVD? And HD=Bluray?"

Yes, I avoid the use of "DVD" because Bluray is a DVD!

Certainly some SD footage should look pretty good scaled to HD, I think that's a judgement call you need to make on a case by case basis. If it was typical home movies shot on 8mm film I'd have serious reservations, modern good SD cameras in capable hands are another matter.

[i]"I also came across something I really do not understand...."[i/]

I've only once upscaled SD to HD. Source material was Digital Betacam, subject was product shots of food with slow pans. I de-interlaced first using Mike Crash's smart de-interlacer and then upscaled to 1080p. Results were very good. However motion was very slow, the only part of the frame the de-interlacing indicated it was switching to interpolate was the steam rising from the food. The products contained no fine detail either that's have given the game away

I think I can understand why you're seeing "ghosts", have you tried changing the De-Interlace method in your project settings and see what that does?

Best understanding I have is that when Vegas scales it combines the two fields, scales and then re-interlaces. During downscaling this seems to work very well. During upscaling I'm not so certain at all. Interlace footage always seems problematic to scale well hence why I de-interlaced first in my efforts at upscaling.

So many of us have grappled with this issue for years. I'd really like SCS to explain what's going on inside Vegas. I'm very happy with the resultsI can get but I don't really know why it works and that troubles me when I try to do more with Vegas. I've had some oddball things happen too, usually I can adjust my workflow and get rid of nasty artifacts but it's all a bit hit and miss.

Bob.

I think I can understand why you're seeing "ghosts", have you tried changing the De-Interlace method in your project settings and see what that does?

It made no change.
Here is how it looks:

If you check the checkbox "Blend instead of interpolate.." in the Mike Crash's smart deinterlacer, you will see something similar.

I tried the deinterlaced you mentioned, it was no success for me before I learnt to set the project's properties corresponding to the media!! Such an obvious thing, and I overlooked it. I am glad for this tip you gave me, it might be crucial to my project!
I will deinterlace before I do any scaling, I think this will be the best solution in this case.
There are a lot of settings, in this smart deinterlacer, I am not sure which one is best..

ingvarai

"There are a lot of settings, in this smart deinterlacer, I am not sure which one is best.."

Glenn Chan had an article on how to use it but I cannot find a link to it from his main page.
You need to set your project to Field Order None. De-Interlace Method = None.
The FX itself kind of explains itself.
You want field based de-interlacing.
If you set it show what it's doing helps as you adjust I find. Anything being Blended shows as grey, anything being interpolated shows the source in color.

Excuse my vagueness, working from memory here.

There are better de-interlacers available. Twixtor has a very good reputation for a price. Pretty certain there's things that run in VDub as well that use motion vectors.

Bob.

Something weird has happened, after I installed the smart deinterlacer. I do not claim this is the cause, it might be pure coincidal. I will post a new thread on this, it is about the AVI uncompressed codec.

ingvarai