It was a backing track for my “demo” entry in Revision 2012 Webbrowser Demo round. You can download the full production here: http://pouet.net/prod.php?which=59160
It actually got second place in that round. Not so much because it was good but because others were even worse. 
Now there is a video of the demo up on youtube too: (Recorded from the party screen, not capture)
Looks pretty nice! The song is pretty good to! May I ask how you created this demo?
It’s nothing special, it’s HTML5 Canvas with javascript displaying some photos and applying some effects on them. If you want to study it bit closer then download the whole thing and just view the source, I didn’t pack any of the code: http://scene.org/file.php?file=/parties/2012/revision12/web_browser_demo/anotherspring.zip&fileinfo
I even included the tool for creating the bits of javascript video in the middle and the XRNS to sync data converter. Feel free to ask any questions if you want to know anything specific. But there isn’t much, very basic stuff.
Well I gotta admit that you totally peaked my curiosity when I saw “html demo”. Never heard about such things before. So yeah I might take a peak into what you’ve done. Thanks a bunch!
The winner in this round was totally awesome 3D demo using WebGL. Browers are pretty capable of doing fancy graphics nowadays. I sure hope to see (and make) even more impressive stuff in the future. 