Circumference of the sun is 4,379,000 km, it goes behind the sun at about 22:00 on the 15th and emerges at about 3:30 on the 16th, so that's 5.5 hours.
That's almost 400,000 km/h or 110 km/s.
The timing is hard to determine from the video, and the disc of the sun is actually smaller than the screen that blocks it in the video, but the comet would travel further too because it wouldn't be right at the surface.
Gives an order of magnitude anyway.
Used this video for times:
http://www.youtube.com/watch?v=pnjeHWwdksg