That was my big problem with the video. I'd like to see real-time dynamic behavior of a needle and record. A static image every 10 seconds is not the same thing.
Edit: here's an example of what I mean. It's a slow-motion video of a topfuel dragster. Just positioning that dragster statically down a dragstrip and taking a picture every few feet won't show you the essence of what's happening. Look at the tires. Look at the vibration. Look at the flames.
I dunno. Maybe my unease is not as relevant with something simpler such as a needle and record.
You would need to record several thousand frames per second to produce something other than a blur when looking at a record producing audio in real-time. Human hearing extends up above 20 KHz and vinyl records are designed to handle this. Recording a normal object at tens of thousands of frames per second would require a very expensive camera and intense lighting. Doing this through an optical microscope would be substantially more difficult, and a current world class electron microscope would probably be incapable of such frame rates.
The scale of a vinyl record groove and needle suggests that a good optical microscope would be sufficient. However, this appears to be a case of a fun project chosen to test out a tool, rather than a tool chosen specifically for the project.
https://www.youtube.com/watch?v=xLmpkPjkozs [esp. around 1:00]