FFmpeg are free and open source tools to process videos, create and modify them. They are very fast and used by many applications and websites worldwide.
Live Class Composite uses this tool to enhance the application features offering a way to export interactive composites merging video and images, FFmpeg is called by our application to perform this tasks and you only have to make sure to have this tool installed in your computer to be able to use this extra features.
Most probably they are already in your computer and you only have to tell Live Class Composite the path to the executable.