AccessViolationException occurred in AForge.Video.FFMPEG.dll

Question

AccessViolationException occurred in AForge.Video.FFMPEG.dll

I have a camera class, in this class I used a timer and in my tick event I save a video using AForge.NetVideoFileWriter in C ++ / Cli (x86, .net framework: v4.6).
This should not happen as it is managed code. But even if I complete the try catch block, the program crashes because of AccessViolationException. I checked that the image is not zero. Something related to VideoFileWriter. This happens at any time between application startup up to 30 minutes of work.

An unhandled exception of type "System.AccessViolationException" occurred in AForge.Video.FFMPEG.dll Additional information: Attempted to read or write protected memory. This often indicates that another memory is corrupted.

In Visual Studio output, I see

An exception was thrown at 0x0C4D689F (swscale-2.dll) in the test.exe file: 0xC0000005: location of the access violation record 0x09F83D80. Exception: "System.AccessViolationException" in AForge.Video.FFMPEG.dll

the code:

 private: System::Void Video_Recorder_Tick(System::Object^  sender, System::Timers::ElapsedEventArgs^  e)
  {
      Bitmap^ save = ConvertMatToBitmap(image); //function to convert opencv Mat to .net Bitmap        
      if(writer!= nullptr)
       writer->WriteVideoFrame(save);
       delete save;
   }

  VideoFileWriter ^writer = gcnew VideoFileWriter();

  private: Void load_VideoWriter()
  {
    writer->Open("C:/video.avi", 640, 480, 10, VideoCodec::Default);        
  }