How to tell if a CD is Encoded?

 That should have been HOW, not IF —  thank you, Apple auto-correct… 

Thanks Erik and folkfreak!  The discs do say "Compact Disc Digital Audio", so it sounds like they're PCM.  Probably Redbook, but there may be no way to tell.  I didn't realize CD's were exclusively PCM, or that DSD was only done on DVD's; good to know. 

But, of course, this opens up a whole nest of related questions!  I've been restocking my music collection with some of my favorites from the 60's and 70's (my original library was stolen), and noticed that many of them have been reissued or remastered.  Usually these versions are selling for much less than the originals, and I was wondering what might have been lost in the process.  Some of them say Compact Disc Digital Audio, some say DSD Remastered, one says "2008 Digital Remaster and Stereo Mix" (with no indication of CDDA or DSD), and another says it's a 2004 Legacy Reissue of the original 1986 recording, with no indication of CDDA or DSD. The crystal case says CDDA, but it's not indicated on the disc or enclosure, so I wouldn't bank on it (also, it was made in Mexico, so I'm doubly skeptical).  

Aside from pure curiosity, one of the reasons I'm asking is because my DAC is a delta-sigma (Benchmark 1), and I'm wondering if I would get better SQ from an R2R DAC, at least with the Redbook discs.  Any thoughts?  

PS to Geoff: good point; I should have said "encoded", not recorded. 

Thanks for the response folkfreak-- I did know that Redbook was the original CD standard format, at 16/44.1 (Sony-Phillips 1980), but I  thought that some more recent recordings were being pressed to disc in higher density/bitrate formats, such as 48/96.  Am I wrong about that?  Unfortunately, most folks have gotten used to calling all these discs "CD's", which makes things even more confusing. 

Your second to last paragraph says that there is "no commercially available disc format" for higher rate DSD, but that seems to contradict the markings on several albums I bought recently (2002 remasters of Rolling Stones such as Let It Bleed and Beggars Banquet), that say they are "DSD Remastered" -- are you saying those are remastered in DSD, and then re-converted to PCM?  I can't understand what the point of that would be.

Fascinating -- thanks for the explanation.  Can you recommend a good book that covers these topics?

If a disc says "Remastered in DSD", doesn't that mean the contents of the disc are encoded in DSD?  If not, we really need to establish a lexicon.

@folkfreak -- you said you "listen to my red book upsampled to dual DSD" -- I don't understand.  If a disc is encoded as Redbook (16/44.1), that means a 16 bit sample of the analog waveform was taken 44,100 times a second.  How can you get better sound out of that track by upsampling -- aren't you limited to the resolution of what's on the disc?

That's a good start -- I have never seen this topic described using visual analogies, and it is much easier to understand the concept that way.  Thanks again!