Technology has come a long way in a few years time. A few years ago I started experimenting with a laptop and a usb webcam.
Today, I'm using a smartphone set up as ip camera and a laptop with usb webcam running NetCam (as ip camera), both transmit wirelessly an MJPEG stream to Kinovea on a Surface tablet. Kinovea delay's the stream, Chrome casts the screen to Chromecast hooked up to a beamer.
The only part that needs to be plugged in to power is the beamer.
A few things that could be improved:
2-3 second delay when casting full screen to chromecast. This could be solved if Kinovea would cast a stream
Image quality, but that's a lot due to my cheapness: use better camera's. If I would drop Chromecast and hook up the Surface tablet directly to the beamer the image quality would improve a lot. This could also be improved when Kinovea would cast to Chromecast directly.
Full screen playback, I know in the latest beta an attempt is made to enlarge the playback screen but a lot of screen area is still not used for video playback resulting in a smaller image on the beamer output.
Overall I ended up (currently, I'm always looking for improvements) with a portable solution which is setup very quick.