Which players are able to decode both?
Thansk for your input!
The NAD Master Series M55 decodes both. I've got it in my system now for demo. It's sounds great. Fit and finish is great and built like a tank.

On HDCD and redbook it's fantastic IMHO. I only have two SACDs and they sound great too. But take that with a grain of salt because I have limited experience with the SACD format.

Denon 2910, 3910, 5910. Newest Arcam.
Classe Omega
hdcd is just a trademark....not a thx, or dolby....most current redbook cd's meet hdcd standards whether they pay to use the trademark or not.
Cary's new SACD player does both -- the 306 SACD I think it is.
Jaybo, with all due respect, I think your mistaken.
Jaybo, check your facts. I was under the understanding that while HDCD is not a different format like SACD, there is extra sonic "information" on HDCD discs that can only be retrieved by HDCD compatible DACs.
hdcd is a 20 bit format decodable via the PMD engine
HDCD starts with 88.2 khz sampling @ 20 bits. The HDCD encodes processes this data stream by performing sample rate conversion. Based on instantaneous signal content it then chooses from a collection of digital processes to reduce the 20 bit data to 16 bits. The encoder also modulates the low order sample bit to signal what process is in use at a given time.

The HDCD decoder contains a reconstruction filter that is a perfect conjugate of the filters used by the encoder for sampling and sample rate conversion. It uses the low order bit modulation to determine which process the encoder used for data reduction and applies the appropriate inverse function to restore the 20 bit data stream.

Non-HDCD dacs simply process the 16 bit data stream and ignore the extra information included in the low order bit modulation.

Definitely more than a trademark.