i'm burning purchased albums into CDs.
with dithering(ssrc ath) used, i think i need to decode those aac to wav files of the bit depth as they are originly stored

it's obviously more than 16bit
but how can i tell if they are encoded from 24bit or 32bit?

and, why using quicktime decode the m4a file into a 32bit wav file, then down to 24bit, it differs from the one directly converted 24 bit file.
below is a amped pic, +120db



thx~

If you're burning to CD, you need to use 16 bit, since thats what CDDA uses.

Also, those purchased tracks are probably 16 bit originally, though some may have been from 24 bit sources.



The square wave effect you see is the result of single bit changes, probably rounding error.