1st sample is 3gpp encoder he-aac

2nd sample is nero 4.2.1.0 he-aac

Ok, first check - I tested the files with FAAD2 and CT's reference encoder:

FAAD2 : decodes both files OK
CT's reference encoder: decodes both file, but Nero's file becomes mono

Also - 3GPP file is encoded without parameteric stereo - maybe that is the problem with your phone.

question though, my phone does not support PS, but, it will decode 3gpp encoded files in mono, but with nero's files, it will decode in mono, but also missing the HE part.

We will do more check on differences.

It would be great if you can send us PS file that gets decoded as HE mono, so we can compare that too.

here are samples in 24kbps, both are PS, and usual nero behaviour of mono decoding, but with no HE

1st sample is 3gpp encoder

2nd sample is Nero 4.2.1.0

edit: uploaded wrong nero sample