That was fun, now how about going in the other direction? Figuring out what sounds were made by looking at a video, a web page and paper published this year show how that is done.
"A key observation in our work is that the vibrations that sound
causes in an object often create enough visual signal to partially
recover the sounds that produced them, using only a high-speed
video of the object. Remarkably, it is possible to recover comprehensible
speech and music in a room from just a video of a bag of
chips." (or as the video shows, a plant will work too)
The method works with a standard video camera too, now you can eavesdrop without any special equipment.
The Visual Microphone: Passive Recovery of Sound from Video The link above has samples to listen to along with a link to the PDF paper.
