50% is a wee exaggeration, surely? Deinterlacing could possibly make
the keying process easier. May also be necessary for online/digital
monitor viewing.
There's one or two deinterlace plugins for After Effects, although
neither those nor AE's built in deinterlacer is recommended by many.
If you do deinterlace, probably best to do it at the end, using PPro --
after you've saved an interlaced version for safety of course.
When shuttling 'i' files back and forth AE, keep an eye on AE's
'Interpret Footage' settings to make sure it's got the field order
correct.
For the next shoot consider hiring an AJA iOHD converter box.
You'll be able to up-rez your 1080i HDV to full 1080p during
ingest. ioHD was exclusively developed for Final Cut/Apple's ProRes
422 codec, but now that ProRes 422 is available for PPro, things
are changing.
http://www.aja.com/html/products_Io_IoHD.html
Darren.
x-gf.com