Flicker is a common problem that occurs when non-pro people shoot videos using non-pro equipment in Auto Mode. Out of the thousands of scenarios, you will most commonly see this when you shoot under household LED lighting, & it happens because of shutter speed mismatch. You will also notice this when you try to shoot slow motion video in low light. There are plug-ins that will help you remove this irritating flicker, but they are all paid options. The video linked below will show you how to remedy this problem for absolutely free, without using any plug-ins, and in any editing software that you use. You just need the ability to work on a multiple-clip based timeline.
In case you belong to that rare breed that doesn’t like videos, there are step-by-step instructions down below as well.
Start by duplicating your target clip.
Then place the duplicate right on top of your original clip.
Then slide the clip on top, one single frame to the right.
Then set the opacity of this clip to 50%.
In most cases with light to medium flicker, you will immediately notice that your problem has gotten solved.
For severe cases, make two duplicates, thus 3 clips in total.
Slide the middle one frame to the right & then set its opacity to 67%.
Slide the top clip two frames to the right & then set its opacity to 33%.
This will solve most of the clips with severe flickers, in case you run into any problem still, get in touch with me, drop me a mail, firstname.lastname@example.org
You will notice a drop in sharpness because you are adding offset clips on top of each other, but you can always add slight Sharpening back by using adjustment layers on top. Of course I know the math behind, how to avoid flicker when I shoot, but I always have this nice little trick as a backup.