Photo CD Audio

Overview
Many Photo CD discs back in the day had an 'audio' folder with files named audio##.pcd

Some of these are just CDDA audio and can be converted with: sox -t cdda

Others can be converted with: sox -t raw -r 44100 -c 2 -b 16 -e signed-integer audio54.pcd garble.wav

Note in both cases however there is some sort of 'distortion' that follows the rhythm of the track (non random, non periodic). It almost sounds like there is some sort of additional data embedded within the audio, but haven't come up with any way to properly handle it or filter it out.

Software

 * SoX

Sample files

 * https://telparia.com/fileFormatSamples/audio/photoCDAudio/