The Library of Congress has posted some previously unseen footage from Altamont on their online archive. Twenty six minute home movie that unfortunately has no audio but has some great close up footage of the bands including a couple that were not in the movie - Santana, Jefferson Airplane, Flying Burrito Bros with nice footage of Graham Parsons fronting the band, Crosby, Stills, Nash and Young. I am halfway through and so far no violence shown. Without the violence it looks like a typical late 60s festival with primitive staging and way too many people crowding around the bands on stage. 
https://www.loc.gov/item/2020600221?loclr=blognsh

Very cool!  Thanks for the head's up.

Bill, tgo

Sweet.  But I wouldn't give for audio!

Peter

Apparently someone is already working on adding audio... seems like it would be difficult even if you are a good lip reader and knowledgable about the songs being played. The footage of the Stones is relatively useless but the rest kind of cool... nice to be reminded that music was actually played that day, the event itself and the violence is usually the focal point. Even without audio you can feel the amount of energy that Santana's band is generating just by looking at them performing.

That's a lot of people!