Another way to convert to MIDI file is as follows.  Musitech makes
a program called Midi Scan which scans sheet music and converts it
to MIDI score.  It can handle 8 staves at one time.  It tends to make
a few minor errors both in reading the score and in converting it to
a MIDI file.

It's most distressing failing is that the tempo is precisely accurate.
It also doesn't do too well with expression.  What I am saying is that
you will have to do a lot of editing after it is done to get a decent
piece of music.  Musitech also makes a less expensive program called
Piano Scan which is the same, but it will only scan 2 staves, such as
a piano score.

I usually find that it is easier to hand play the music and then
correct my mistakes.

Jim Cook