Quotation from Mechanical Music Digest  2003.04.20-09:

Rollook MIDI Editor for Street Organ Music

Arthur Nichols asked 2003.04.17.07 about transposing and locating
forbidden notes in MIDI files.

My own frustrations in that area resulted in an attempt for the Windows
PC world, a MIDI editor called Rollook that you can download from my
home page at http://w1.879.telia.com/~u87902212/rollook/rollook.zip
(226K). The zip includes a manual of just 9 pages. Rollook is by no
means a complete system, or free of bugs, but includes some features
you may have use for.

One is a histogram showing what notes are present in the file, and
a facility to indicate what notes are permitted in your instrument.
From that information it is very straight forward to locate forbidden
notes and do transpositions. You can also do some useful checks like
locating too small inter-note time gaps and overlaps between channels.
Another facility is punched paper template printouts.

Its piano roll display is in the correct orientation, that is, notes
from left to right and time downwards. Just to tease Cakewalkers and

Johan Liljencrants
Stockholm, Sweden