There is literally no way to tell from that video. Despite being a C-span live feed it cuts out multiple times during the shooting. If I just go off what I hear, there was like a 30 second pause at one point between shots. I just don't know what to make of this whole thing. Right now the only two things I notice that are truly different is the behavior of the soldiers who actually call out the salute (they never do--they just call for the first shot without announcing what kind of salute it will be or what the intervals will be--odd when you compare it with Trump's), and then of course the intervals weren't at 3 seconds.

I have yet to see a video where 21 shots are clearly heard though. I'm really befuddled on that point as it stands.