Thanks for the input! My target machine is an anchient feature phone
that supports mp3 and AAC only. Its limited storage space combined with
a speaker that does not make high bitrates justice tells me that AAC is
the best choise of codec in this case.

/fuumind

tor 2016-06-02 klockan 08:19 +0200 skrev Adam Borowski:
> On Thu, Jun 02, 2016 at 07:22:38AM +0200, fuumind wrote:
> > I wish to convert several thousands of audio files mostly in mp3 format
> > to AAC
>
> I don't get why one would want to convert _to_ AAC. It's a format both bad
> and proprietary, thus hardly supported by free software at all. It wins
> with mp3 only at very low bitrates and is actually _worse_ (although usually
> within the error margin) than mp3 on high bitrates.
>
> If your target machine is anything non-ancient, you want opus, it thoroughly
> beats both mp3 and aac at any bitrate. Even I, with untrained ears and
> shitty gear, can ABX 320kbit mp3 on some samples. Never tried with aac but
> it's said to be similar. On the other hand, pretty few people can ABX opus
> at just 96k, so encoding at 128k is fine if you're paranoid about quality.
> Yes, it is that much better.
>
> If your target _is_ ancient, you want mp3 for compatibility. You'd need to
> encode at a crap quality to let aac be significantly better.
>
> > but AAC does not present itself as an available target
>
> It's patented out of the wazoo.
>