I agree the video is a bit fuzzy and shaky, so we can't be sure it is a gun, yet. The police probably know, as they will have it as evidence. But we will have to wait to find out the fuller story.
The policeman who shot the guy, has released a statement (of sorts), via his defense lawyer, basically saying that the suspect/victim had a gun, which forced the policeman's self defense reaction.
E.g. (I've seen many other references to the following, so it seems to be reliable)
Source:
Which seems to confirm that the driver had a
GUN (presumably close enough to the guys hand, to use against the policeman), at the time of the shooting.
I.e. This may have been legitimate self defense by the policeman.
But we need to be careful, because we have NOT got the full information yet, and the information released by the policeman's lawyer, could be biased/shaped to help defend the policeman, rather than get to the proper truth of what happened.