How to record a live video of yourself with a transparent background?

Question

I always watch and wonder how some youtubers have a little window on a corner of a gameplay or something...

My doubt isn't on how they get the image, my doubt is on how some youtubers get the video of themselves with a transparent background on top of the gameplay.

I know this requires a green screen, but I really want to know how this gets automatically edited. I have seen some live gameplay with the transparent effect.

How do the youtubers get a transparent background on a live feed?

What I am trying to achieve is, recording myself on a live feed, but with a transparent background... If you see what I mean...

Answers much appreciated,

Sid

Answer 1

I really want to know how this gets automatically edited.

The technique is called chroma key and consists of considering as transparent all pixels of the colors within a specified range. This is usually used with a bluescreen or a green background. The image is then simply layered over another background.

As you have noticed, chroma key is not limited to postprocessing: a lot of software products can do this in real-time for live streaming.

By the way, if you have used Google Hangouts, one of the effects consists of replacing the background by an image. Don't be mislead by this, since this has nothing to do with a bluescreen and doesn't require any specific color for the background; I imagine that Hangouts' algorithm rather assumes that parts that don't move are the actual background.