Re:IP Over QR Code
by userbinator on Saturday November 19, 2016 @08:44PM
(#12996814)
Combine with some steganography and you can use this method to broadcast data over otherwise normal-looking videos: https://news.ycombinator.com/item?id=12166332
Re:IP Over QR Code
by andreareina on Sunday November 20, 2016 @12:49AM
(#12997486)
In practice you're limited to sending information at half the theoretical maximum resolution[1], so 5 fps. Still has some very interesting possibilities.
[1] https://en.wikipedia.org/wiki/Nyquist_frequency (updated link, s/rate/frequency/)
Rather than just being a fun little project, I could see there being a few practical uses for this: If you could modify the protocol so that the 'QR code' could dynamicly resize down to be in the worst case 1 pixel for the whole screen, you could potentially do line of sight communication using just laptops between tens of kilometers away[1]. There aren't a lot of situations where you'd need that, but I could see scientists on a remote research mission finding in handy to be able to just pull out their laptops and send messages between mountain tops by just double-clicking some kind of application.
A crappy webcam that could do 10 frames per second that was looking for an entire monitor in the on/off state could send O(10) bits per second which would be useful enough to send small text messages. If you used a telescope, you could actually send real amounts of data.
[1] https://www.technologyreview.com/s/539826/how-far-can-the-hu...
Edit: Upon close inspection of the article I linked, it says later in the article that you could only see the flame 2.76 km away, but I don't think that changes my point very much since a laptop screen would be brighter.