The verb recaler means readjust here, not that other recaler. It is also unrelated to recalculer.

Recaler means caler again, i.e. adjust something with the help of a cale: a wedge (German Keil).

The idea is to draw a cat on a “read sheet music” (midi clips), possibly with this software, then slightly readjust (i.e. recaler) the notes to reach an acceptable piece of music.