anchor.diff:    int _rotation = 0;
     double _width = 0.0, _height = 0.0;
     bool _mirror;
  +  double _aspectRatio = 1.0;
     MediaStream _srcObject;
     RTCVideoViewObjectFit _objectFit =
         RTCVideoViewObjectFit.RTCVideoViewObjectFitContain;
     StreamSubscription<dynamic> _eventSubscription;
  -  VideoSizeChangeCallback onVideoSizeChanged;
  -  VideoRotationChangeCallback onVideoRotationChanged;
  -  dynamic onFirstFrameRendered;
  +
  +  VideoAspectRatioCallback onAspectRatioChanged;
   
     initialize() async {
       final Map<dynamic, dynamic> response =
  
positive.code:   void initState() {
      super.initState();
      _setCallbacks();
    }
  
    @override
    void deactivate() {
      super.deactivate();
      renderer.onVideoRotationChanged = null;
      renderer.onVideoSizeChanged = null;
      renderer.onFirstFrameRendered = null;
    }
  
    void _setCallbacks() {
      renderer.onVideoRotationChanged = (int textureId, int rotation) {
        setState(() {
          _updateContainerSize();
        });
      };
      renderer.onVideoSizeChanged = (int textureId, double width, double height) {
        setState(() {
          _updateContainerSize();
        });
      };
      renderer.onFirstFrameRendered = () {
        setState(() {
          _updateContainerSize();
        });
      };
    }
  
    void _updateContainerSize() {
      double textureWidth = 0.0, textureHeight = 0.0;
      if (renderer.rotation == 90 || renderer.rotation == 270) {
        textureWidth = min(renderer.width, renderer.height);
        textureHeight = max(renderer.width, renderer.height);
        aspectRatio = textureWidth / textureHeight;
      } else {
        textureWidth = max(renderer.width, renderer.height);
        textureHeight = min(renderer.width, renderer.height);
        aspectRatio = textureWidth / textureHeight;
      }
    }
  
    @override
  
negative.code:   RTCVideoViewObjectFitCover,
  }
  
  typedef void VideoAspectRatioCallback(double aspectRatio);
  
  class RTCVideoRenderer {
    MethodChannel _channel = WebRTC.methodChannel();
  