Chroma Key Live

Free Real-time HD Green-Screen Software

Chroma Key Live “keys out” selected areas of live video, allowing a background to show through.  It features Syphon I/O, HD resolutions and full GPU acceleration.

A few years ago, some of my students were doing a green-screen shoot and needed to visualize the chromakey while shooting, so their actors could see the composite while they performed. We didn’t need the advanced features of professional software like VeescopeWirecastBoinxTVVirtualEyez, or Visual Communicator so I made my own solution.

Chroma Key Live performs a basic realtime chromakey on your computer screen, in SD or HD resolutions, with adjustable tolerance and edge fade. The foreground and background sources include Quicktime inputs (ie webcams, DV cams, capture cards…), Syphon Streams, and Quicktime media (movies, stills). The foreground and background layers can be independently scaled, positioned, and mirrored (so your actors don’t see themselves backwards). The playback of Quicktime media can be controlled from the keyboard for easy cueing and rehearsal.

Some background…

In the days of analog video, chromakey was accomplished in the TV studio in realtime. The camera’s live signal would be routed through a keyer in the control room and delivered back to an on-set monitor. This way, the production team could see exactly how the actor looked when composited over the background image. Of course, you would need an expensive studio or at least a video mixer.  Now, in the digital era you can add chroma key effects in post-production using inexpensive software. But they can’t be easily visualized during production. How do you shoot a complex green-screen scene when all you see is an actor against a big green wall?  Chroma Key Live makes it simple again. Run the output from your camera into a Mac, then click on your background and it will disappear, revealing the movie or still image of your choice. Switch to full-screen and call “action!”