DSD
From JRiverWiki
DSD is the format used for Super Audio CD's. Please see the article on DSD at Wikpedia more information.
Your DAC must support it. Only a few do.
DAC's that support DSD include: Playback Designs
DSD Downloads
http://www.ps3sacd.com/dsd_downloads.html
Ripping Super Audio CD's
Article at computeraudiophile.com on ripping SACD's on an old PS3.