Comment by florian_s

The source code is actually small enough to be posted here

  navigator.getUserMedia = navigator.getUserMedia || 
  navigator.mozGetUserMedia;
  
    window.onload = () => {
      // Create favicon link element
      const favicon = document.createElement('link');
      favicon.rel = 'shortcut icon';
      favicon.type = 'image/png';
      favicon.href = '../../images/favicon.ico';
      document.getElementsByTagName('head') . [0].appendChild(favicon);
      // Create hidden canvas
      const w = 32;
      const h = 32;
      const canvas = document.createElement('canvas');
      canvas.style = 'display: none';
      canvas.width = w;
      canvas.height = h;
      document.body.appendChild(canvas);
      // Grab canvas context
      const ctx = canvas.getContext('2d');
      // Create hidden video element
      const video = document.createElement('video');
      video.style = 'display: none';
      video.width = canvas.width;
      video.height = canvas.height;
      document.body.appendChild(video);
      // Assign user media to video and start loop
      navigator.getUserMedia({video: true}, stream => {
          video.srcObject = stream;
          video.play();
          loop();
      }, () => {});
      // Loop forever
      const loop = () => {
          // Copy video to canvas
          ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
          // Set canvas to favicon
          favicon.setAttribute('href', canvas.toDataURL());
          // Loop
          setTimeout(loop, 100);
      };
  };

From https://github.com/wybiral/code-art/blob/master/projects/tin...