What is Super Bit Mapping

I just bought a cd on Sony, Tchaikovsky and Sibelius Violin concertos, Isaac Stern and the Philadelphia Orchestra under Eugene Ormandy. The playing is superb and the sound quality very high, at least on first hearing. A sticker was added on the front of the jewel case proclaiming SBM. What is it? What are the advantages or disadvantages of this process.
Lennardd. Thanks. I don't know if it is the SBM, but this cd sounds, indeed, very good. The quality of the instrumentalist and orchestra don't hurt either! Regards.
The above link probably explains it better than I can, but it's Sony's patented dithering process to go from 24 or 20 bits down to the 16/44.1 redbook CD standard. Their goal is to capture more than 16 bits of sound in the 16-bit format. They claim that it makes a 16 bit CD sound more like 20 bits of information. Many of the Columbia/Legacy reissues use the SBM process and I think most sound quite good.
Super Bit Mapping is Sony's patented noise shaping process, which can be used w/wo redithering. It reshapes the noise spectrum,including the roundoff noise spectrum associated with bit length reduction, so that instead of having a flat amplitude spectrum at all frequencies, the noise amplitude is lowered across most of the audio band and correspondingly raised at high frequencies, where it is supposedly less audible.