Check this out:One of AACs advantages was that if you re-encode an AAC file at the same bitrate that it is encoded in, that the encoder will not remove any additional data. So, re-encoding an AAC file 100 times over at the same bitrate will cause no degradation in sound quality.
I'm pretty sure that's not true.
I was pretty sure that wasn't true either. But the link that @Rollin provided shows that AAC handles re-encoding better than other codecs.
A test from 2014, and encoders have improved since then. Basically, AAC not suffering any noticeable generational losses after as many as 100 reencodings, while both Ogg Vorbis and Opus suffered considerably after way less.
Maybe someone would feel like throwing different xHE-AAC encoders into that sort of test?
Thank you. That is very interesting.