RE: Found good speed measurement software
And by the way.. it says on the site 10 seconds are enough for a good measurement... I don't know what speeds these guys are doing, but 10 seconds for me on a straight line would be a plane out of sight.
My experience in this matter is that you need about 1 second for a good pass, providing you do a good low pass (about 3 to 5 feet) over the camera... the lower and the straighter (the means constant altitude too), the better...