code: def _no_more_pads(self, element):
          
          # Sent when the pads are done adding (i.e., there are no more
          # streams in the file). If we haven't gotten at least one
          # decodable stream, raise an exception.
          if not self._got_a_pad:
              self.read_exc = NoStreamError()
              self.ready_sem.release()
docs: The callback for GstElement's "no-more-pads" signal.