AAC as an Episode Asset option?

Is there a way to set my Episode Assets to AAC as an option? I’m surprised not to see it in the list of available choices considering YouTube, iPhones, and Androids all use it as their codec of preference for audio files.

Usually m4a is used for aac encoding and that is available. See also: http://www.differencebetween.net/technology/difference-between-aac-and-m4a/