I'm finally doing some digital music. I've ripped the Royal Platinum
CDs using iTunes and those files became MP4s. CSDS doesn't seem to
recognize these as sound files.
Is that something you can fix or do I need to do something else?
I have no experience with MP4.
Possible solutions to your problem:
Use the Winamp player via CSDS. You might need to download
and install a Winamp plug-in to be able to play MP4.
Convert them, or rip them as MP3 (or WAV).
Send me a sample MP4 file, and I'll play around with it
and try to get it to work.