The orig IIRC was a windows media player format file you could try searching for it, though most of what he's covering is in this collection of papers https://www-cs-faculty.stanford.edu/~knuth/aa.html

I think he gave this talk twice, once in 2000 and once at HERCMA 2001

These videos were just released yesterday from the Stanford archives in honor of Prof Knuth's 81st birthday so there may not be higher resolution versions available. Maybe this is a subtle call to some aspiring hacker to re-res them with a super-resolution deep learning algorithm. What a cool gift to the world that would be.