Nope, it's not magic, just really clever editing.
You know when your video footage has that really nasty flickering in it? Yeah, that's just the worst thing ever. "Where's the hot shot that turned a strobe light on during the shoot," you wonder, but hey, I promise it wasn't the hot shots' fault. It's banding, or flickering, which happens when the frequency of a light source doesn't match up nicely with the frame rate of your camera. If you're like, "Yeah, cool information...wish I knew that before I shot all my footage," don't throw your work out just yet. Filmmaker Peter McKinnon has a ridiculously quick and easy hack that may fix your flicker problem completely. Check out his tutorial below:
Earlier this year, we posted a similar "flicker fix" technique from Blue Mantle Films that had a couple of extra steps and left a bit of a blurry double-exposure look to the footage. McKinnon's technique, which you might've previously seen on a Philip Bloom tutorial several years ago, simplifies the process slightly by requiring just two video layers and doesn't seem to produce much visible blur.
Now, here are a couple of things to keep in mind.
First of all, this "hack" won't work in every banding situation. It really depends on the frequency of the light, as well as the frame rate you used. Try it out on your flickering footage, see if it works. If it doesn't, you might want to play around with the placement of the duplicated clip.
Second, the best way to deal with banding is to avoid it altogether. If you shoot a lot of high-speed video, you'll definitely want to do the necessary calculations to ensure you're choosing the right frame rate in relation to your light source's pulse frequency. (There are calculators online, as well as apps that will do this for you.) While most types of lights, including fluorescent, LED, and incandescent, could potentially cause banding, TV, computer, and other types of screens are the biggest offenders, but slowing down your shutter a bit can help alleviate the problem.
If you're not sure about how your lighting will affect your footage, do some tests before starting your shoot, so you can fix any banding issues before it's too late.