https://www.youtube.com/watch?v=t6M9EbWbhZI
I remember that video from a few years ago. If I'm not mistaken it was filmed during some demonstrations against some socio-political situation (I don't remember which one, there have been so many in Brazil). At the time, on another forum, this video was presented and some time after someone found a video made by a TV station using a drone that was flying above the crowd, and the movement of the drone corresponded to what we see on the video.
The video I remember wasn't as dark as this version.
That could certainly explain it I suppose.