"But the researchers came up with a second technique, using the "rolling shutter" typical on digital video cameras, to extract enough information from the video to still recreate high-frequency audio."
Find article here: http://www.theguardian.com/technology/2014/aug/05/mit-crisp-packet-eavesdrop-audio-sound
Find article here: http://www.theguardian.com/technology/2014/aug/05/mit-crisp-packet-eavesdrop-audio-sound