Hey new member here. I've been trying to figure out how to do this in FCP but no luck so far. It's pretty much red flashes that look like film strips in between cuts or sometimes on the clips themselves. It looks like film strips.
You can see it in the beginning of this video.
Can anyone tell me if its a plugin, or overlay, or a technique..
I'm guessing it's a film leader laid over the video footage with the opacity at about 70%. That's how I've done that in the past. You can probably find some stock footage leader footage online somewhere. Or it could just be a filter.