1 HN user recommended this demo1 month2015–2026score 1
Years with an HN recommendation, 2007–2026
HN commenters cite it as the classic demonstration of audio recovery from video in surveillance and privacy discussions.
MIT researchers show that sound can be recovered from silent video by analyzing tiny vibrations in objects such as a potato chip bag. It works even with consumer cameras by using rolling shutter.
“it can be possible to extract audio from video, by careful processing of the small motions the sound induced in objects in the frame” (HN, 2017)
"security cameras outside of stores" would be in public areas, yes? The Lifehacker link you pointed to says "Generally speaking, you have the right to record video in all public spaces without need of consent." Now for the fun part - it can be possible to extract audio from video, by careful processing of the small motions the sound induced in objects in the frame. See [this video] . High-speed camera is best, but at the end they show how a regular consumer-level camera can also be used.
Recovering sound from tiny motions in video, even consumer cameras
See this - [this video] They show audio captured from a 60fps video from a DSLR exploiting the rolling shutter. I'm not sure if you can use less than 60fps though?
Audio captured from 60fps DSLR video via rolling shutter
Here similar experiment, 6 years ago: [this video] If you think that actual government agency cannot do even more easily with better equipment in 2020 you're kidding yourself.
Earlier similar experiment recovering audio from visual vibrations
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