Converting Piano Player Rolls into MIDI Data

Very cool new-tech/old-tech application here:

Midi Scans of Player Piano Music Rolls
The process of scanning music rolls first generates a very large file, basically containing hundreds of thousands of pixels. That initial .CIS file is then converted into an events .SCN file, which in turn is converted into a .MID music file containing a single piano track. The files available here are the final relatively small .MID files which may be "played" through most any computer's sound card, an electronic keyboard, or in a Disklavier, PianoDisc, PianoMation, Pianocorder equipped piano. All are Midi Type 1 files, with identifying data imbeded within the tracks through the use of CakeWalk.

2,650 titles available for non-commercial use. Other people are doing this as well -- here is another site with over 700 scanned rolls. Turns out there is even an International Association dedicated to this:

The International Association of Mechanical Music Preservationists (IAMMP) is a group of volunteers dedicated to the preservation of music rolls.
Music rolls, developed in the mid 1800's, were used in player reed organs, push-up piano players, player pianos, and similar instruments. Much of this music is in danger of being lost as the paper rolls continue to deteriorate. IAMMP members are constructing electronic scanners, based on the pioneering work of Richard Stibbons, to convert the punched paper music into digital form. The digital files are being archived and converted to appropriate data formats to be played on the computer, Disklaviers and similar instruments or, in a different form, used to operate perforators to create fresh rolls of original accuracy. Membership in this group is open to anyone who has an interest in helping to preserve our mechanical music heritage. Use of the information contained in this e-group is primarily for hobby purposes.

This website has plans for building your own scanner using parts from a cheap flatbed scanner and some surplus motors and gears. Lots of software and schematics available. Very cool tech!