Ok, lemme take a shot at this. If DS is to be believed, the 8 second clip may have been taken accidentally when the group shot in front of the garage took place. I know it happens to me sometimes when I go to take a photo using my phone and it's still set to video mode. IIRC, the timestamps between that clip and the jpg are pretty close to one another. If it's depicting someone wearing a red cap*, it may be the person operating the phone or someone else who was there at the time, but not in the final image. That video was never encrypted because it doesn't actually show anything incriminating, and it's the only one DS could ever play because it was the only one in its original 3gp format. The other two video files on the server were the ones that were heavily encrypted.
In the VICE story, it seemed like there were a bunch of people involved. Maybe one of those people shared the link with DS at some point and that was the extent of his involvement, but I get the feeling there's more to it than that.
*Red is the Goonies' gang colour.