MissionPlanner.OSDVideo.StartCapture C# (CSharp) Method

        private void StartCapture()
        {
            int hr;

            ISampleGrabber sampGrabber = null;
            IBaseFilter capFilter = null;
            ICaptureGraphBuilder2 capGraph = null;

            if (System.IO.File.Exists(txtAviFileName.Text))
            {
                // Get the graphbuilder object
                m_FilterGraph = (IFilterGraph2) new FilterGraph();
                m_mediaCtrl = m_FilterGraph as IMediaControl;

                // Get the ICaptureGraphBuilder2
                capGraph = (ICaptureGraphBuilder2) new CaptureGraphBuilder2();

                // Get the SampleGrabber interface
                sampGrabber = (ISampleGrabber) new SampleGrabber();

                // Start building the graph
                hr = capGraph.SetFiltergraph(m_FilterGraph);
                DsError.ThrowExceptionForHR(hr);

                // Add the video source
                hr = m_FilterGraph.AddSourceFilter(txtAviFileName.Text, "File Source (Async.)", out capFilter);
                DsError.ThrowExceptionForHR(hr);

                //add AVI Decompressor
                IBaseFilter pAVIDecompressor = (IBaseFilter) new AVIDec();
                hr = m_FilterGraph.AddFilter(pAVIDecompressor, "AVI Decompressor");
                DsError.ThrowExceptionForHR(hr);

                IBaseFilter ffdshow;
                try
                {
                    // Create Decoder filter COM object (ffdshow video decoder)
                    Type comtype = Type.GetTypeFromCLSID(new Guid("{04FE9017-F873-410E-871E-AB91661A4EF7}"));
                    if (comtype == null)
                        throw new NotSupportedException("Creating ffdshow video decoder COM object fails.");
                    object comobj = Activator.CreateInstance(comtype);
                    ffdshow = (IBaseFilter) comobj; // error ocurrs! raised exception
                    comobj = null;
                }
                catch
                {
                    CustomMessageBox.Show("Please install/reinstall ffdshow");
                    return;
                }

                hr = m_FilterGraph.AddFilter(ffdshow, "ffdshow");
                DsError.ThrowExceptionForHR(hr);

                //
                IBaseFilter baseGrabFlt = (IBaseFilter) sampGrabber;
                ConfigureSampleGrabber(sampGrabber);

                // Add the frame grabber to the graph
                hr = m_FilterGraph.AddFilter(baseGrabFlt, "Ds.NET Grabber");
                DsError.ThrowExceptionForHR(hr);


                IBaseFilter vidrender = (IBaseFilter) new VideoRenderer();
                hr = m_FilterGraph.AddFilter(vidrender, "Render");
                DsError.ThrowExceptionForHR(hr);


                IPin captpin = DsFindPin.ByDirection(capFilter, PinDirection.Output, 0);

                IPin ffdpinin = DsFindPin.ByName(ffdshow, "In");

                IPin ffdpinout = DsFindPin.ByName(ffdshow, "Out");

                IPin samppin = DsFindPin.ByName(baseGrabFlt, "Input");

                hr = m_FilterGraph.Connect(captpin, ffdpinin);
                DsError.ThrowExceptionForHR(hr);
                hr = m_FilterGraph.Connect(ffdpinout, samppin);
                DsError.ThrowExceptionForHR(hr);

                FileWriter filewritter = new FileWriter();
                IFileSinkFilter filemux = (IFileSinkFilter) filewritter;
                //filemux.SetFileName("test.avi",);

                //hr = capGraph.RenderStream(null, MediaType.Video, capFilter, null, vidrender);
                // DsError.ThrowExceptionForHR(hr); 

                SaveSizeInfo(sampGrabber);

                // setup buffer
                if (m_handle == IntPtr.Zero)
                    m_handle = Marshal.AllocCoTaskMem(m_stride*m_videoHeight);

                // tell the callback to ignore new images
                m_PictureReady = new ManualResetEvent(false);
                m_bGotOne = false;
                m_bRunning = false;

                timer1 = new Thread(timer);
                timer1.IsBackground = true;
                timer1.Start();

                m_mediaextseek = m_FilterGraph as IAMExtendedSeeking;
                m_mediapos = m_FilterGraph as IMediaPosition;
                m_mediaseek = m_FilterGraph as IMediaSeeking;
                double length = 0;
                m_mediapos.get_Duration(out length);
                trackBar_mediapos.Minimum = 0;
                trackBar_mediapos.Maximum = (int) length;

                Start();
            }
            else
            {
                MessageBox.Show("File does not exist");
            }
        }