title: Watermark video source live
body: <p>I would like to watermark a video that is taken from for instance a webcam.</p>
  
  <p>in the normal setup you would see this flow
  webcam -> capture software</p>
  
  <p>what i would like to do programmatically is to 
  webcam -> watermark -> capture software</p>
  
  <p>how does one do this ? is there any frameworks for this?
  a requirement is not to capture and then store to disk since this is for a live stream.</p>
  
  <p>also, would there need to another fake camera device to able to pull the signal from the processed watermark output signal?</p>