Why does a mirror reverse left and right, but not up and down? and does it have something to do with us having two eyes?
How did you turn the camera?
You could have turned it towards you by turning it bottom over top and then you would have to vertically flip the image, but you probably would have never even thought to do it.
So instead you chose to turn it left to right so to get a mirror image you have to flip the pixels left to right.
You’re human so flipping a camera upside down seems quite silly but that’s just an artifact of your environment.
As you can see, the mirror is reversing up and down, not left and right.
Well, a mirror gives you a different picture than a webcam and a computer screen (unless the webcam software flips the picture along the x axis).
Now why is that, that the software needs to flip along the x axis? It is actually because a mirror mirrors around the the z axis, so it switches front and back.
That is exactly what happens if I open Facetime on my Mac and hold something in the camera.
To be a bit more precise: There are two streams generated. One is shown to yourself, and this one works like a mirror. The other one is shown to remote participants and this one is not flipped.