This is one of many taken by protesters and independent media on Friday, June 15, 2012.
This particular video was linked to the comment section of this blog by 'Janick'. It was also embedded in a tweet by Hiroko Tabuchi, New York Times reporter in Tokyo. (I hope she didn't get into trouble with the bureau chief for tweeting the June 15 event.)
For more videos of the event, go to this blog.