What codecs can be used by iOS ringtone files (.m4r). I know only about AAC and ALAC, is there anything else? I can't find any official information on this question.
I dont know if this will help you at all but I use DBPower Amp Converter and batch converter for all my sounds. It has a lot of codecs to choose from not sure if this is what you need but give it a shot maybe it;ll work.