Courtesy of Adafruit
Guide by John Park
For creating video tutorials and livestreaming with MakeCode, there's a simple, yet effective way to display video inside of your session. This mini guide will show you how!
The first method is to pick a connected USB camera as your background.
USB Camera Method
Inside of MakeCode, pick the gear icon and then click the Green Screen On menu item.
Choose one of your USB video cameras from the list.
Your video camera will stream inside of the browser as a background behind all of the MakeCode graphical elements!
You can also choose to use a green background that can be knocked out with a chroma key setting in your capture or livestream software.
From the same menu item, pick the Green background choice.
This will turn the background of MakeCode to pure green.
This will show up in your layered capture or streaming software as a layer that can be chroma keyed.
Pick the chroma key option. Your software may default to pure green or pure blue (less common) and you should also have choices to pick a specific alternate color and adjust the threshold.
Now, you can switch out your layers dynamically as you normally would in your capture or streaming application.