def clearDevice(self):
        """Remove the current stream
        """
        print(self.pre, "clearDevice: ")
        
        self.report("clearDevice")
        if not self.device:
            return
        if (self.mvision_process==None):
            return
        
        self.filterchain.delViewPort(self.viewport)
        self.filterchain.releaseShmem(self.shmem_name)

        self.mvision_process.deactivate() # put process back to sleep ..
        
        self.main_layout.removeWidget(self.mvision_widget)
        
        self.filterchain = None
        self.device = None
        
        self.video.update()