I just read Mr. Dayson's suggestion for using "Piano From Above" to
visualize piano rolls [201126 MMDigest]. I used this program before
and I actually recommend using it instead of "Synthesia".

In Synthesia, when notes reach a certain shortness the note lines do
not become shorter. "Piano From Above" shows that actual note length by
making the falling note lines shorter and shorter until they are a
miniscule single pixel. This makes a much more detailed visualization.

Piotr Barcz