docs: def _conversion(self, input_signal, vad_file):
      """
        Converts an external VAD to follow the Spear convention.
        Energy is used in order to avoind out-of-bound array indexes.
      """
      
      e = bob.ap.Energy(rate_wavsample[0], self.win_length_ms, self.win_shift_ms)
      energy_array = e(rate_wavsample[1])
      labels = self.use_existing_vad(energy_array, vad_file)
      
      return labels