J. S. Bach's Air on a G-string, from his 3rd orchestral suite in D major, BWV 1068.
Q: Where can I get free sheet music for this piece?
A: The score in the video can be downloaded from here:
And here's a piano arrangement of it
Q: Who is performing?
A: I licensed this recording from Premium Beat; it is performed by the "Apollo Symphony Orchestra" which is just a catch-all name for "various European music orchestras with professional classical musicians and singers." In other words, I don't know, and the people who licensed the recording to me won't tell me.
Q: What does this have to do with a g-string?
A: The short answer is that many people know it by the name "Air on the G-string," so I put it in the title to help people find it. You can read more about this here:
Q: What is the real name of this piece?
A: It is the second movement of Bach's Orchestral Suite No. 3 in D major, titled "Aria" ("Air" is the English word for "aria").
A while ago, when I was learning to read music, I found I could follow the score for a single instrument much more easily than a score with many instruments.
To make complex scores easier to read, I made condensed scores (in which the notes of all the instruments were on a single grand staff—like in piano music). Unfortunately, this made it hard to see which instrument was playing which note. I tried coloring the notes by instrument. That worked better, but since all the note symbols were about the same size, a long note for one instrument could easily be lost among shorter notes of other instruments.
The solution was to use bar-graph notation. At first I drew paper scrolls by hand but later I learned how to make them with computer software. Over the years, I experimented with other ways of showing music.
Recently, a violinist told me he wanted to use my visualizations in live performance, so I made a version of my software in which the timing of the animation was controlled with a crank. We tried this out with a symphony orchestra; it worked!