I think there's two aspects: the filming itself, and then the posting of that filming on social media. Even if you don't find any specific restrictions, I'd still call the temple personally and ask to speak to a member of the Temple Presidency about your plans. And then when you arrive, you might also want to let them know you're doing the filming so they're aware.
I can't imagine there are filming restrictions, otherwise every temple wedding group outside every temple would be in trouble!

And there's plenty of videos shared on social media of the bride and groom exiting the temple, walking around the grounds, etc. But perhaps others on the Forum are aware of specifics when it comes to a more "official FB page", rather than personal social media posts.