Just checked the actual youtube page and it is a simulation using a programme called FWSIM http://www.fwsim.com/ the comments were..
"Published on Jan 3, 2013
Happy New Year, YouTube! :)
I hope you all had a pleasant party celebrating the dawning of a new year. We all made it, safe and sound, to the year 2013, and I wanted to continue the party by sharing this fireworks display I created & actualized. It took me a little over a week to complete, and I am very happy with the outcome. All of the shells are custom-made by me, and I take huge pride in the handiwork that went into bringing them to life. I hope you all enjoy the show. :)
The music choice used for this display is Thomas Bergersen's (Two Steps From Hell) "Heart of Courage." Truly a great musical arrangement.
The great software used to mastermind a production like this is FWSim.