The Raspberry Pi can output video via a http protocol in an MJPEG stream and it can also stream via RTSP which uses the h264 codec. So far I have successfully managed to get both of these formats working.
The difficulty then is to pull them into a program which can manipulate them, using shape or colour recognition and chroma-keying. The programmes that I previously highlighted as potential solutions failed to work.
Both Pure Data and Quartz Composer are effective for the manipulation of video from a webcam attached to the computer, but are less capable receiving a stream from over a network. Pure Data’s pix_video and pix_film objects can access webcams and files, but not network streams. Quartz Composer has a patch that has been created for it that can work with certain IP cameras, but only selective Axis Camera models are compatible.