They could be expired rentals. Sometimes long after I've watched a rental, it still appears as being there taking up space, and I have to try and open it again so that it says "sorry, this movie is expired" before it frees up the space.
Also, videos in text messages from others count.
But I check in photos and video apps and there are 0 videos.
Where are said videos?
I had the same problem it's under camera roll recently deleted folder