我想用RTSP去推Image图片，应该在RTSP的例程代码上怎么修改

我想用RTSP去推Image图片，应该在RTSP的例程代码上怎么修改？

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https://developer.canaan-creative.com/k230_canmv/zh/main/zh/api/mpp/K230_CanMV_VENC%E6%A8%A1%E5%9D%97API%E6%89%8B%E5%86%8C.html#id3
在VENC的4.2这个例程中，我添加了一个img.drawstring，但是显示的颜色、位置和数量都不对

            while True:
                os.exitpoint()
                yuv420sp_img = sensor.snapshot(chn=CAM_CHN_ID_0)

                ####### 这是我添加的 ###############
                yuv420sp_img.draw_string_advanced(10, 10, 32, "TEST", color=(0, 0, 0))

这是实际运行的效果

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推流这部分我应该怎么修改，才能推img这个图片呢？

    def _do_rtsp_stream(self):
        try:
            # streamData = StreamData()
            # while self.start_stream:
            #     os.exitpoint()
            #     # 获取一帧码流
            #     self.encoder.GetStream(self.venc_chn, streamData)
            #     # 推流
            #     for pack_idx in range(0, streamData.pack_cnt):
            #         stream_data = bytes(uctypes.bytearray_at(streamData.data[pack_idx], streamData.data_size[pack_idx]))
            #         self.rtspserver.rtspserver_sendvideodata(self.session_name,stream_data, streamData.data_size[pack_idx],1000)
            #         #print("stream size: ", streamData.data_size[pack_idx], "stream type: ", streamData.stream_type[pack_idx])
            #     # 释放一帧码流
            #     self.encoder.ReleaseStream(self.venc_chn, streamData)

            img = image.Image(1920, 1080, image.ARGB8888)
            img.clear()
            img.draw_circle(50,50 ,2, (45,100,55), 1)
            # 推流到RTSP


        except BaseException as e:
            print(f"Exception {e}")
        finally:
            self.runthread_over = True
            # 停止rtsp server
            self.stop()

        self.runthread_over = True