code: function gotMedia(mediaStream) {
    // Extract video track.
    videoDevice = mediaStream.getVideoTracks()[0];
    log('Using camera', videoDevice.label);
  
    const captureDevice = new ImageCapture(videoDevice, mediaStream);
    interval = setInterval(function () {
      captureDevice.grabFrame().then(processFrame).catch(error => {
        err((new Date()).toISOString(), 'Error while grabbing frame:', error);
      });
  
      captureDevice.takePhoto().then(processPhoto).catch(error => {
        err((new Date()).toISOString(), 'Error while taking photo:', error);
      });
    }, 300);
  }
docs: We have a video capture device. Exercise various capturing modes.
  @param {MediaStream} mediaStream