On Mon, 22 Jul 2002, Richard Rauch wrote:
> What is "combing"?  I've never heard this term before and hadn't noticed
> anything in playback of which the term is suggestive.

It's when fields from mismatched frames are displayed as one frame...
so the odd rows are from one picture and the even ones are from another.
Google turned up:
http://www.aluminumstudios.com/digitalvideo/advanced/interlaced/interlaced.html
which has an explanation and some sample pictures.