Django, as far as the front-end is concerned, has little to do with actually capturing the video. This is going to be on the frontend with your browser. Depending on your audience, they might not have browser web capture available and will have to use a browser plugin like flash or silverlight, as mentioned in
http://www.html5rocks.com/en/tutorials/getusermedia/intro/. Otherwise, follow that link and see if that'd suit your needs.