How to create a chroma key effect without a backdrop?

In this video I show you how I create a chroma key effect without a backdrop

It's really easy and you should try it, the only thing you need it's to have a flat green wall somewhere in your house and light it as even as possible. In this case, I did it quite sloppy but you know it's part of my style, I need to improve a lot. Check out the video, at the end I explain my setup.