Missing element: MPEG-4 AAC decoder on 1.28.5 Windows

Probably a very basic mistake, since I’m new to Gstreamer. Fresh install from the website, and every info I get makes me believe that almost everything including ugly and bad plugins should already be installed together by using the runtime and development option in the installer. In this case, I’m trying to open a mkv, with audio that is in aac.
Am I wrong? Did I miss a step?