First of all, I love this software.
I think there is a need for an important feature in the future. First of all I primarily use AB for re-encoding and joining existing mp3s. When I first started using this software I assumed that using the "High Quality" setting would automatically give me the highest possible quality given the source mp3s. For example: I thought if I used the "High Quality" setting a 64k mono mp3 would be output as a 64k mono m4b. Unfortunately this is not the case, the 64k mono mp3 is output as a 128k stereo m4b; using the "High Quality" setting "up-converts" the the file greatly increasing the file size without increasing the quality (e.g. if the source is mono and you select stereo, the file size is doubled!).
The suggestion I have to work around this:
-provide a "Highest Possible Quality" setting which does not "up-convert"
-Or allow the changing of quality settings at the time of conversion (which has already been suggested)
-At the very least warn the user of what they are about to do
Thanks for the great software.
cameron