Since the original agreement was only for the unedited video, I'd negotiate what seems reasonable to all parties. Photographers frequently claim copyright over their work.
That said, perhaps granting joint copyright ownership would be the best way to go. I wouldn't charge them too much, unless you perceive that they may use your edited video to profit somehow…
Every year, we head to CES to check out the latest innovations in consumer technology and look for the next big thing in video production. CES 2019 was no exception.
