I'll bet you it's in-engine, and not in-game.
Or in other words, it's all done in the editor, and robably because when this teaser was made, half the stuff you see in there wasen't finished yet.
It's different from "pre-rendered" though, because an in-engine video does show you the real graphics of the game, all the models and effects that are used are the same as the ones used in real time by the game, though a lot of the animation work might not be.
Pre-rendering is usually used to make cutscenes (as in video ones, not the "we're taking control of the camera to show you something" ones), you know how cutscenes can have a 100 times better graphics than the game? That's pre-rendered, that's when they make models and textures that are a ton better than the ones used in the game, and has a render-farm process them into a video.
Sadly, we sometimes do see developers try to pass of pre-rendered work as if it where the game in their marketing, i know EA has certainly pulled that stunt a fair few times for their TV commercials.