Yeah, I looked it and what I see is a bunch of non-sine shapes like in the original video. Your theory gets shot down by sawtooths as well as squares, and there are plenty of those in both.
Nope. Watch the origianl. Then watch the second video. Then watch the guitar/violin video.
The latter two show various amplitudes on a sine wave with the weird spacing on the periodization. You also get the traveling sine wave effect as expected. While the higher frequncy sines look peaky, they are still rounded.
What you’d expect no matter what rate your digital camera was capturing at.
Now watch the first video. There are well defined squares. So...
Fake.