code: def process_frame(self):
          
          input_name = self.inputs[0]
          output_name = self.outputs[0]
          in_frame = self.input_buffer[input_name].get()
          out_frame = self.outframe_pool[output_name].get()
          out_frame.initialise(in_frame)
          if self.transform(in_frame, out_frame):
              self.send(output_name, out_frame)
          else:
              raise StopIteration()
docs: Get the input and output frame, then call
          :py:meth:`transform`.