Wirecast 4 for Mac

From Telestream:

Telestream Wirecast 4 is a live production tool, that allows you to easily broadcast live events and create professional webcasts from any location. With the intuitive interface and fully integrated streaming capabilities. Wirecast makes it easy for anyone to share live experiences and build a global community. Wirecast lets you stream multiple live video cameras while dynamically mixing in other media such as movies, images, sounds, etc. Features such as Chroma Key (green screen), transitions and built-in titles allow you to create beautiful, professional broadcast productions for the web in a snap. You don't need to be a video professional. It's easy and affordable - all you need is a camera, a computer and an internet connection to create and broadcast your professional video productions to any audience, live or on-demand.