[M4IF Technotes] AAC question

[Alf Rieckmann]

Sorry, I guess I am actually misusing the MPEG4 list but I have a 
question about MPEG audio AAC (ISO+IEC+13818-7-1997), which some of the 
audio guru's listening to the mailing list might be able to answer.
I was actually looking for the reference decoder code and thought that 
it would come with the standard somehow. It doesn't, at least not if I 
purchase from ANSI.
I was looking around at the web where I found the following decoders/ref 
software:
FAAC decoder (release 0.5) : 
<http://www.mp3-tech.org/programmer/sources/faadsrc05.zip> - AAC - C
faadsrc05.zip
MBSoft AAC Decoder Winamp plug-in (release 0.2) : 
<http://www.mp3-tech.org/programmer/sources/mbaacdec.zip> - AAC C/C++
mbaacdec.zip
MPEG-4 Audio Reference Software (08/99 release) : 
<http://www.mp3-tech.org/programmer/sources/refsoft990809.tgz> - 
AAC/MPEG-4 - C
refsoft990809.tgz
which of these could/should I use?
I am only interested in the 13818-7 AAC decoding.
Does the MPEG4 ref SW cover MPEG2 (superset) or is it the same?
Thx for help
Regards
Alf