code: public String getCaptureDevice() {
  		switch (OsUtils.getOS()) {
  			case WIN:
  				return "dshow://";
  			case OSX:
  				return "qtcapture://";
  			case NIX:
  				return "v4l2://";
  			default:
  				throw new WebcamException("Capture device not supported on " + OsUtils.getOS());
  		}
  	}
docs: Get capture device protocol. This will be:
  <ul>
  <li><code>dshow://</code> for Windows</li>
  <li><code>qtcapture://</code> for Mac</li>
  <li><code>v4l2://</code> for linux</li>
  </ul>
  
  @return Capture device protocol
  @throws WebcamException in case when there is no support for given operating system