Hmm…Sounds like a field dominance issue to me. Did you try rendering out with upper-field first? It’s possible that the camcorder recorded your footage as upper-field, which would mean that rendering out lower-field first you reversed the field order which would explain the stuttering motion. Unfortunately, it’s pretty much impossible to tell what your field dominance is on your computer monitor, being that it is a progressive display. This is also true for you plasma monitor. The best way for you to find out what type of footage you have to render out a few seconds, one set to upper-field and the other set to lower-field. Burn it to DVD, then play it on a Standard Definition CRT television. Which ever one playback smoothly is what your camcorder records footage as. This is not entirely uncommon…we have a real-time MPEG-2 encoder here that crops D1 NTSC (720×486) footage to 720×480 by removing 3 pixels from the top and 3 from the bottom. Which winds up making our once lower-field dominant footage upper-field.
By the way SD CRT TVs are the best way to look at interlaced Standard Def footage. It’s the only way to tell if you having field issues, jittery pixel thin lines, if your colors ore bleeding, etc.
Hope this helps and good luck
Michael