Phil,
The question is: Export to what? If you mean Windows Media or Quicktime or Flash, then no problem. If you mean to DVD, forget it. DVD has set rules.
Start by exporting the DV AVI at 720X576.
All you need to do is create a custom project at the frame size you want to use, let’s say 576X576 with square pixels. Then import the normal sized clip and put it on the sequence. The extra will hang over the edges and not be seen.
Then export the exact same frame size of the project to any of the export codecs you want.
Steven
https://www.stevengotz.com