You need to convert them to .wav files.
A free program that will convert, and also allow you to edit music files, is
AudacityCDex is a free CD ripper, and will convert, back and forth, between .mp3, and .wav
With Audacity, you'll need to make copies of your files, before converting, unless you don't mind the originals being converted.
CDex will batch convert, leave the originals intact, and would probably be the easiest to set up, and use.
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