Quick update: I am slowly adding support for the Syphon Framework to some of my apps. (It’s a high-speed pipeline for video data, so you can send the output of one app into the input of another.) Chroma Key Live is almost done, but no specific timeline after that.
Meanwhile, I was excited to discover that Blair Neal has hacked together Canon2Syphon which converts the live USB feed from a Canon DSLR into an almost-HD Syphon stream. (Thus, you could use your DSLR as an input into my updated software without needing any expensive HDMI capture hardware.)
Speaking of inputs, the lack of manual exposure on Mac-compatible webcams has been a pain for too long. Sluggo’s UVC-CTRL software enables manual controls on many UVC-compliant webcams (ie – most modern ones). Follow the installation instructions carefully: make sure to download the required library and the graphic interface (GUI) too. It made my Logitech camera finally useful for tracking, chromakey, etc where manual exposure is critical.