def stop_record(self):
        '''
        stops recording and wait for the video_process to finish writing to file and join
        First puts a None (End of Video) frame into the frame queue and wait for writing
        process to terminate.
        '''
        self.video_queue.put(None)
        self.video_process.join()
        self.is_recording = False
        print('finished recording video {}'.format(self.num_eps))

        stops recording and wait for the video_process to finish writing to file and join
        First puts a None (End of Video) frame into the frame queue and wait for writing
        process to terminate.
        
surreal/env/video_env.py