This report from GamingBolt.com suggests that the Uncharted 4 trailer is indeed running in real-time - a simply phenomenal achievement. We've studied the video in a little more depth and have concluded that it's definitely running at native 1080p resolution (as opposed to being rendered at a very high resolution, then scaled down - a process known as super-sampling). Small clipping anomalies, a touch of specular aliasing on Nate's shirt as he sits up, along with some shadow aliasing on his forehead also suggest a real-time render. On the face of it, we're still looking at some pretty incredible anti-aliasing here for a real-time technique on a game running at 60fps, particularly when it comes to the perfect, artefact-free rendering of Nate's hair - but the combination of the low contrast setting, slow camera movement, motion blur and depth of field would work well generally in making aliasing much less of an issue.