private void makeVideoView(string channelId, uint uid)
    {
        GameObject go = GameObject.Find(uid.ToString());

        if (!ReferenceEquals(go, null))
        {
            return; // reuse
        }

        // create a GameObject and assign to this new user
        VideoSurface videoSurface = makeImageSurface(uid.ToString());

        if (!ReferenceEquals(videoSurface, null))
        {
            // configure videoSurface
            videoSurface.SetForMultiChannelUser(channelId, uid);
            videoSurface.SetEnable(true);
            videoSurface.SetVideoSurfaceType(AgoraVideoSurfaceType.RawImage);
            videoSurface.SetGameFps(30);
        }
    }