Sometimes looking at the comments and the YouTube channel might give some clues. From the description of this video:
So, he’s made a few improvements to the source video. Note the source video is from TicTok and a user named Mr. TR3B if I’m reading it right. Here are some more videos of black triangles from the channel:
As far as I can tell so far, ALL the various black triangle videos are sourced to the same TicTok Mr. TR3B. So, it looks like The Camera Obscura channel is stabilizing TicTok videos from Mr. TR3B ... Read even more