[Icecast] AAC support?

[Akos Maroy]

Greg J. Ogonowski wrote:
> By adding support for AAC/HE-AAC to Icecast2, the project is certainly
> about freedom.
> It gives users the freedom to choose whatever codec they want.
> 
> HE-AAC/aacPlus, because of its efficiencies and good sound quality at
> ultra low bit-rates, is rapidly becoming a very popular streaming audio
> codec solution.  Even though the codec is not free, and there are
> up-front costs involved, savings in bandwidth alone more than offset
> this cost.
> 
> Icecast2 is certainly a part of this, and we thank the Icecast2
> developers for supporting AAC/HE-AAC/aacPlus.

but still, _how_ is it supported?