Recovering Audio from an Audio-less Video

2 min readJan 17, 2021

Let’s talk about sound and microphones for a second. Microphones are embedded in nearly every single digital device nowadays and their primary purpose is to detect tiny little vibrations in the molecules of air which we call it as ‘sound’ or ‘audio’.

Now, what if we could recover those vibrations just by observing the surface of an object upon which the vibrations just bounced off? Can a surface be turned into a microphone?

What is Sound?

Sound is nothing but a disturbance in the medium of air over a period of time. Disturbance refers to the vibrations and collisions of air molecules. Imagine ‘sound’ like a ripple created in water when a stone hits the water. Those vibrations cause our eardrums to vibrate and this information is processed by our brains to give you a feeling of sound.

Recovering Sound from Objects without using a Microphone

Let’s imagine you are eating chips while watching television and the packet of chips is laying around in a corner of the room. Now, the sound from the television can create minute deformations on the surface of the packet causing it to vibrate. The vibrations are so subtle that they can’t be seen with a naked eye. Now, what if we can recover the audio of your television by just observing the vibrations of the surface of the chip packet?

A team of researchers at MIT, Adobe and Microsoft have found a way to do that.

Source: MIT Research Paper

They used a high speed camera to capture the subtle vibrations of the surface of an object and then analyzed that data to literally recover audio signals. Isn’t that cool? The packet of chips can be literally turned into a microphone.

Well, if you are still not impressed, then check out this website which converts images into audio.

That’s all for now. Signing off.

Originally published at techthatthrills blog.




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