If there is no video proof of wilt chamberlin scoring 100 points how do we know it even happened. Plus BQ?

I could understand some things in history that might not be factual like B.C time.....but what Chamberlin did is only a couple of decades ago and there are ppl still living on earth during his 100 points performance....YES ITS true my uncle actually witnessed it...YOUR GRAND KIDS ARE GOING TO ASK THE SAME QUESTION 60 YEARS FROM NOW ..."IF KOBE BRYANT 81 POINT PERFORMANCE IS REAL"? ON Y/A