The problem that Leonardo Forti describes in his post sounds very
familiar in several aspects.  Debouncing electrical contacts is
really a classical issue in the interface field.  From my experience
I can state that R-C combinations are often the first choice but in most
cases not the best.  Digital methods, e.g., filtering with a monoflop
["one-shot"], are much more efficient and flexible.

If you have the unwanted events in your MIDI file, this is somehow
similar to the chain perforations in scanned rolls files.  Back in
2003 I posted a solution for this problem in 030120 MMDigest.  Due to
some attached files this has been archived in

  http://www.mmdigest.com/Gallery/Tech/tenten_cal1.html 

If the software provided there is not adequate, it can be modified
easily.

Best regards from Germany, where spring is waiting for its start.

Walter Tenten