Webcam video dimensions are flipped on mobile

TL;DR: swap webcam width and height

On several mobile devices / operating systems webcam video width and height may be flipped.

E.g you request specific input video width and height:

const width = 360
const height = 540

player.use(
  new Webcam({
    width,
    height,
  }),
)

Dom.render(player, "#web-ar")

But get output video width and height flipped:

$("#web-ar").width() // 540
$("#web-ar").height() // 360

It's a known platform-specific webcam bug.
To deal with it you have to swap webcam width and height:

const width = 360
const height = 540

player.use(
  new Webcam({
    width: height,
    height: width,
  }),
)

Dom.render(player, "#web-ar")

// ...

$("#web-ar").width() // 360
$("#web-ar").height() // 540