I'm using a masked clip over the original clip to try to reproduce a figure in that footage so there's another one in the shot, and I'm using track motion to move the selected figure in the masked clip to a different place in the original clip so I can complete the effect. Hopefully, that makes sense. Everything looks fine in the preview window with the added figure, but when I go to render, the added figure shows up in a different place. I'm trying to figure out why and how I can accomplish this effect... essentially cloning something in the shot.

Could it be the half-field of an interlaced frame is giving you placement grief?

Not sure. The placement is way off though from what is shown. But I was able to find a workaround... the preview is just not accurate so I used track motion to move it a lot more and using render I checked it to eventually get it in the right position. Seems like such a weird problem though. I don't know why the preview doesn't accurately reflect the final render. Thanks for your help.

love to see that clip..I have never used track motion and wonder what its uses are