This post is dedicated for my progress in creating my personal project.
I started this project by choosing what footage I want to use. I chose this footage because I think it's unique that you can have basic green screen technique and also hair replacement for the guy.
My first step is to create the alpha to use in the premult later on. I use 3 keylights to get the edge matte for each window. As you can see the image below, there are a lot of black parts that aren't supposed to be there.
I created a core matte to cover up those black spots, so that I have a clean alpha. I combined all the edge mattes and the core matte then give it a bit of edge blur to have a softer edge. I also use LightWrap node to blend the footage into the background. I connect the LightWrap to the background video which I downloaded from the internet.
Next, I did a hair replacement so that it looks more detail on the hair part. I shuffle the green screen footage to the green channel. Then, I did some color grading so that it increases the contrast of the background and the hair.
I merge the background and the result from above with multiply operation and mask it with roto to match the particular shape of the hair. After that, I merge the hair replacement with the result from the premult and here is the comparison for the hair replacement.
Then, I tried to create a reflection for the rear window so it could help to bring this to a next level. I use different video that has different perspective so it looks more realistic when I merge it altogether. I also add camera shake and did some color grading to make it more natural then a basic green screen video.
Here is the screenshot of the final node graph: