voice over, and it was ALL practical effects, NOT CGI which I initially thought it was. The below video talks about it, but it's queued to start at the point where they confirm Howard Shore, so if you want to watch the whole thing, just start it back at the beginning. Shore actually composed the very music in the teaser itself. The rating also confirms this is NOT going to be a GOT rip-off, nor will this have nudity or excessive violence. All good signs.

https://www.youtube.com/watch?v=F4jKpV4Kyic