I have a few videos that were created with a white screen background. They should have been created with a green screen background. Too late now.
Is there any way to change just the background of a small video from whitescreen to a greenscreen without affecting the actual appearance of the spokesperson in the video?
Thanks in advance.
Allen
The chroma-key filter works like how you would if you had used a green screen, but that’s okay because it will work on white too 
This is a video tutorial covering the basics of how to use the chroma-key filters. In your case set the highlighted color to your white background (and a few minor adjustments to your liking) and you should be good to go!
I don’t think it will be possible to change to white screen to a green screen background. Chroma key removes a particular color, in most cases, the specific green color in a video, which is not a color often found in nature. The background screen can be other colors too, but you want it different from colors of a spokesperson i.e. the natural skin color, the shirt, hair etc which means yellow, white, black background are generally not suitable.
You can use the chroma key filter to remove white, but it will also remove any white part in the video eg white parts of the eyeballs, teeth etc and you’ll end up with something rather strange
If you can’t re-shoot the videos, one option would be to crop your spokesperson, then put that in a picture-in-picture in a small window or corner of the video.
Thanks James. You stated pretty much what I had already concluded. After I removed the “white” all I was left with was a ghost with no eyes or teeth. I will be using green screen moving forward for my spokesperson videos. I really appreciate your in-depth response and for taking the time to clarify this.
Have a great evening.