let half;

​

function setup() {

  createCanvas(400, 400);

  video = createCapture(VIDEO);

  video.size(400, 400);

  half = createImage(200, 400);

}

​

function draw() {

  background(220);

  video.loadPixels();

  half.copy(video, 0, 0, 200, 400, 0, 0, 200, 400);

​

  image(half, 0, 0);

  scale(-1,1);

  image(half, -400, 0);

}

​