This appears to be the complete reel of film shot by Roger Patterson in and around Bluff Creek, CA, in 1967 that ends with the famous figure walking away down the creek. Not sure which copy it is, but the video appears to have been made by recording the film being projected (hence the projector noise in the background — the camera used by Patterson did not record sound). It’s fuzzy and low resolution, but interesting to see all the same.
Update: Bill Munns has confirmed on the BFF this is the complete reel on which the famous footage is found:
Yes, this is the complete first reel. It’s identical to the full first reel copy I scanned from John Green’s archives.