Video flickering is caused by your LED lights – here’s what you can do about it.

So you’ve just finished filming a wicked video, and you’re really happy with it – but when you watch it back you notice there’s a strobe effect on it that wouldn’t be out of place in an 80’s disco.

It’s distracting, and you don’t want to post that footage now – but it’ll be a pain to re-record it.

But don’t immediately reach for the delete button, you can still fix it. But first let’s understand where flickering comes from…

 

What causes flickering in videos?

Flickering happens when the LED lights in your room ‘refresh’ at a different rate to your video.

You might think of an LED light as a continuous source, but actually most of them are regularly refreshing at either 50Hz or 60Hz. The 50Hz stands for on/off 50 times a second and 60Hz is on/off 60 times a second.

It’s fast enough that the human eye can’t see it, but it causes problems on videos. That’s why videographers have special video lights, so that their LED’s don’t cause this problem.

And equally, video is often considered a continuous recording, but it is actually made up of individual frames. A standard video in real time might be 25 frames captured for each second of video footage, and in slow motion you might instead capture 100 frames per second of video footage. This is known as the frame rate.

The issue comes when the LED flicker rate and the video frame rate don’t match.

 

Can I prevent flickering while filming?

If the camera you’re using allows you to change the frame rate and shutter speed, then sometimes yes. In the UK, have your camera system set at 50Hz, the frame rate at 25fps, and the shutter speed at 1/50. This should be in line with the LED lights. If the flickering is still present though, then it’s a case of making micro adjustments to the frame rate and shutter speed until you find a combination which works best.

Your other option of course is to invest in an LED video light and turn off the problem LED ceiling lights – or just use daylight for your videos instead.

At VideoHQ, most of our filming is done on site with clients, so we’re well aware we might encounter flickering lights while out and about! Therefore, we have three professional video lights so we can adapt to any situation.

It’s always better to get it right while filming, than to try and fix in post.

Image shows man in shirt and tie being filmed for a testimonial video. He's lit with professional video lights which reduce flickering on the footage

How to remove flickering from a video

But what if you’re filming on a phone or similar, and you can’t change any of those settings?

Here’s a solution I’ve found when editing videos in my editing software, Final Cut Pro X.

  1. Put the offending clip into your timeline
  2. Copy the clip, and paste it on top of itself, so it is duplicated.
  3. With the duplicate clip, move it forward by one frame in the timeline, so it would run one frame behind the original clip.
  4. Set the opacity of the duplicate clip to 50%.

It’s not a perfect solution, as it creates a bit of motion blur, and there are some occasions where it doesn’t work. But it might just save your bacon.

Of course, if you don’t want to worry about any of this when filming videos, give me a shout. My professional LED lights mean you’ll never have to worry about flickering on your video footage again.