Hi Daryl,
Welcome to BuddyDev.

Thank you for posting the question. At the moment, MediaPress does not support generating thumbnails from Video. In future, we do have plans to add a free or paid plugin that allows converting videos/extracting thumbnails.

The problem is, to extract thumbnail you need executable like FFMPEG and a way to maintain a queue. This is going to need significant time and is low on our priority.

Here is a solution though. Any plugin that works with WordPress uploaded videos and extract thumbnails will work with MediaPress out of the box.

I had a look at the list but none of the current plugins have proper support for queuing and that’s why I am not making any suggestion here.

Regards
Brajesh