If you really have fields then you must separate them properly before upscale or you are loosing half your potential resolution as soon as you move or scale the footage.
There are some 3rd party plug-ins that do a very good job of de-interlacing footage but AE does just fine with most footage.
I'd separate fields, create a new comp from the footage, double the frame rate of the new comp, up size the new comp to full HD, apply Detail Preserving Upscale to fill the frame, then drop that comp in a new comp that is the same frame rate as your original comp, turn on frame blending and render your progressive upscale from that.
Thanks for your help. By "separating fields" do you mean choosing "off" in the interpret footage box?
No. The Good Mr. Gerard means to select the field order appropriate for your footage. For for 480, it's lower field first. For 1080, it's upper field first.
Got it. Thanks.For what it;s worth, I'll post the workflow as I understand it. Tests so far look reasonably good, especially since I'm not blowing my 480 clip all the way up cover 1920x1080. Anyway, perhaps this will help someone else:
1. Open a sequence using the 720x480i clip.Open the Interpret Footage box,and under Main choose lower field first under Seperate Fields and also choose Preserve Edges.
2. Then open that compositions' dialogue box and change the ratio from 720x480 to 1920x1080 and double the frame rate. In the case of my clip that would be doubling to 59.94 from 29.97..
3. Then copy that comp into a new comp of 1920x1080 with a frame rate of 29.97. Select Frame Blending and outpu to progressive.
If anybody sees a dead rat in here anywhere, please let me know.