This sort of thing can probably be done with SQL, but that's probably beyond your means (it certainly is mine). I would just export Barcode and then import it as Media label. In the export, be sure to include fields (other than Barcode) to uniquely identify the movie (normally, Title and Year would do). You'll want to get rid of the Barcode values as well. I'm not sure how that can be done. I doubt it's possible to overwrite them with a "null" but it might be possible with a space and certainly is with a ".".
