I'm making a tool that uses a modified JPEG encoder to generate lo-fi, glitchy, images. However, after getting the basics working, I couldn't resist trying it out on some video.
This experiment uses the getUserMedia API to access your camera, copies the video stream to a canvas element, and encodes frames using the JPEG encoder. It's a fairly processor intensive operation, so is definitely not mobile friendly, but should give reasonable framerates on desktop.