The video source is unknown. It's a shaky reproduction without opening or closing credits, but remains a credible overview nonetheless.
For accompanying text, go here:
1968 Democratic Convention, by Haynes Johnson (Smithsonian)
The 1968 Chicago convention became a lacerating event, a distillation of a year of heartbreak, assassinations, riots and a breakdown in law and order that made it seem as if the country were coming apart. In its psychic impact, and its long-term political consequences, it eclipsed any other such convention in American history, destroying faith in politicians, in the political system, in the country and in its institutions. No one who was there, or who watched it on television, could escape the memory of what took place before their eyes.