Short for Super Audio CD, SACD is a special type of audio disc that is read-only and capable of holding more audio play time than a standard CD. Audio can be encoded in stereophonic or surround sound, providing for higher sound quality than a standard audio CD. The SACD is the same physical size as a standard CD and looks like a standard CD, but has the density of a DVD and can be either single layer or dual layer like a DVD.
Introduced in 1999, Sony and Philips Electronics developed the SACD as a joint effort. The SACD features a sampling rate of up to 2.8224 MHz, which is 64 times faster than a standard audio CD. It also can also stream audio data at an uncompressed rate of 5.6 Mbit/s. A hybrid SACD is capable of playing in a standard CD player, but not all SACDs are available with a hybrid layer.