Downconverting 320MP3 to 192... MP3 or AAC?

[Rantipole]

If I have a 320 bit rate song encoded in MP3, and want to "downconvert" it to 192 for space or other reasons, would I be best keeping it as MP3, since it is the same format? Or will going to AAC be better, even in that case?

I know AAC has a reputation for being more "musical" when encoding from an original source. But I'm wondering if, since I would be switching from MP3 to AAC, if the sound gets "confused", and therefore is sticking with MP3 would be better.

(Yes, I know "double compressing" is not something I generally want to do. Just interested in opinions regarding this fact pattern.)

Thanks.

 

[Jolly Jimmy]

AAC or MP3 won't really matter at all, there's going to be a severe quality hit either way. As for MP3 to AAC "confusion", I don't think that'll be a problem.

 

[DustinT]

AAC will have a slightly better sound quality at that bit rate according to the math gurus. But, they will both sound decent so I wouldn't sweat it too much.

 

[TwoBytes]

never double compress!

 

[cluthz]

never double compress!

This!

If you compress something already compressed sound quality gets pretty bad!
Going from 320->192 will most likely sound worse than going from CD->128

 

[Rantipole]

never double compress!

I know! I mean generally, I don't. But needed to temporarily. And actually had already done it to AAC. I just was curious if it made a difference. Still have the original file.

Thanks.