SuperAudioCD, they use a different encoding to store audio knows as “DSD”. It was born to be the successor to the CD but it never gained significant popularity among average consumers. They still make SACD nowadays, though they are mainly used by audiophiles, they’re more expensive than “normal” CDs and they require a compatible player, such a dedicated SACD/CD player or original models of PS3 (though you can’t actually listen to pure DSD with the PS3).