This looks like a very interesting development in the world of midi:
"Zenph Studios, a software company based in Raleigh, has found a way to take a music recording and convert it into a live concert played on real instruments. The concert will be a completely faithful rendition of the original pianists' work.
Zenph resurrected a scratchy mono recording of Bach's Goldberg Variations, made by the Canadian pianist Glenn Gould in 1955 and a recording of a Chopin prelude by Alfred Cortot in 1928. Cortot died in 1962, Gould in 1982.
The breakthrough that Zenph has achieved is to extract the sounds from audio recordings and convert them into a high-resolution version of MIDI, the standard way of coding music for computers. To do so they had to tackle the problem of polyphonic transcription - distinguishing several notes played simultaneously. While researchers have been trying to achieve this for years, previous attempts have managed to identify at best 80 to 90 per cent of notes correctly - with about 10 per cent missing and another 10 per cent wrong (New Scientist, 22 December 2001, p 50)."
Hope they post some demos.