I don't know about the headphone jack as a quasi video output. You could, in theory, sample the video and create an audio stream that was an encoded version of the video (though I suspect resolution, frame rate and color accuracy would all suffer to the point that it was noticeable on the large screens).
The bit that makes it suspect to me is that the iPad already has a VGA output, and even then standard iPhone/iPod Touch has had a composite video output available via the dock connector forever. Since this hack is more about hardware than software, why would you create your own video encoding stack to use the headphone jack instead of just taking the video that already comes out the dock connector?
In order for this to work, the piece that goes next to the screens would have to output a signal that was stronger than the signal actually being fed to the screens to cause the internal circuitry to lock onto the new signal. Seems unlikely to happen in a device that appears to be powered by watch batteries.
I think that something like this is theoretically possible, but requires much different/larger hardware than what is shown in the videos. I'd be happy to be proven wrong though.
Humorously enough, early television in the UK (from 1929-1935) had only 30 lines of resolution and so could be recorded at audio frequencies onto a "Phonovision" disk. You can see some examples at http://www.tvdawn.com/recordng.htm of the low quality of the results.
For a little while, the BBC did broadcasts of 30-line video using two AM radio frequencies (one for the video, one for the audio) that could be picked up by special recievers.
I think the iPhone jack has been abused as a general-purpose communication port before. I'm sure it can output some signal that something can interpret as/translate into a video signal...
That doesn't mean this isn't fake, of course. And I'm not convinced that the jack would have decent bandwidth...
I wondered this myself. While technically you could on a generic computer (a wire is a wire, digital and/or analog), there certainly don't exist any APIs to do this on the iPhone. It would make far more sense to hook up to the dock (for which I believe there are APIs for).
The second giveaway is that you definitely cannot get enough power out of the headphone jack to run any serious electronics, not to mention a transmitter that can apparently transmite hundreds of feet in a crowded place like Times Square.
The iPhone jack can output an analog signal. What if you convert a digital video to an analog signal that can go out through the jack? The transmitter would just amplifies that signal.
Comments
Several comments on the Youtube page say it's fake, chiefly because the iPhone jack cannot output video.
Is this true? If so, is it possible he wrote an app with special drivers to pull this off?
Yes, it's possible. See project HiJack:
http://eecs.umich.edu/~prabal/projects/hijack/
Ah, thanks all. So it is possible, but most likely a hoax for other reasons mentioned in this thread.
Looks like Square (http://squareup.com) to me.
I don't know about the headphone jack as a quasi video output. You could, in theory, sample the video and create an audio stream that was an encoded version of the video (though I suspect resolution, frame rate and color accuracy would all suffer to the point that it was noticeable on the large screens).
The bit that makes it suspect to me is that the iPad already has a VGA output, and even then standard iPhone/iPod Touch has had a composite video output available via the dock connector forever. Since this hack is more about hardware than software, why would you create your own video encoding stack to use the headphone jack instead of just taking the video that already comes out the dock connector?
In order for this to work, the piece that goes next to the screens would have to output a signal that was stronger than the signal actually being fed to the screens to cause the internal circuitry to lock onto the new signal. Seems unlikely to happen in a device that appears to be powered by watch batteries.
I think that something like this is theoretically possible, but requires much different/larger hardware than what is shown in the videos. I'd be happy to be proven wrong though.
Humorously enough, early television in the UK (from 1929-1935) had only 30 lines of resolution and so could be recorded at audio frequencies onto a "Phonovision" disk. You can see some examples at http://www.tvdawn.com/recordng.htm of the low quality of the results.
For a little while, the BBC did broadcasts of 30-line video using two AM radio frequencies (one for the video, one for the audio) that could be picked up by special recievers.
I think the iPhone jack has been abused as a general-purpose communication port before. I'm sure it can output some signal that something can interpret as/translate into a video signal...
That doesn't mean this isn't fake, of course. And I'm not convinced that the jack would have decent bandwidth...
I wondered this myself. While technically you could on a generic computer (a wire is a wire, digital and/or analog), there certainly don't exist any APIs to do this on the iPhone. It would make far more sense to hook up to the dock (for which I believe there are APIs for).
The second giveaway is that you definitely cannot get enough power out of the headphone jack to run any serious electronics, not to mention a transmitter that can apparently transmite hundreds of feet in a crowded place like Times Square.
The iPhone jack can output an analog signal. What if you convert a digital video to an analog signal that can go out through the jack? The transmitter would just amplifies that signal.