Converting MP3 to AAC and outputting to stdout

Question

ffmpeg.exe -i s.mp3 -f aac -

This is the command I run but it doesn't recognize the format AAC.

Requested output format 'aac' is not a suitable output format pipe:: 
Invalid argument

However when I run:

ffmpeg.exe -i s.mp3 -f ogg -

This works.

Also, outputting to a file like this works:

ffmpeg.exe -i s.mp3 o.aac

Any ideas what I'm doing wrong?

Answer 1

When you run this command:

ffmpeg.exe -i s.mp3 o.aac

you may notice the following line in the output:

Output #0, adts, to 'o.aac':

Here, ffmpeg is telling you that it is using the format called adts to generate an .aac file. Use -f adts instead of -f aac:

ffmpeg.exe -i s.mp3 -f adts -