那句话是定义显示视频的位置


/// <summary>
        /// Luoz:start all the interfaces, graphs and preview window
        /// </summary>
        bool StartupVideo(IMoniker mon)
        {
            int hr;
            try
            {
                if (!CreateCaptureDevice(mon))
                    return false;                if (!GetInterfaces())
                    return false;                if (!SetupGraph())
                    return false;                if (!SetupVideoWindow())
                    return false;#if DEBUG
                //DsROT.AddGraphToRot(graphBuilder, out rotCookie); // graphBuilder capGraph
#endif                hr = mediaCtrl.Run();
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);
                return true;
            }
            catch (Exception ee)
            {
                MessageBox.Show(this, "Could not start video stream\r\n" + ee.Message, "DirectShow.NET", MessageBoxButtons.OK, MessageBoxIcon.Stop);
                return false;
            }
        }        /// <summary>
        /// Luoz: 创建用户选择的设备设备
        /// </summary>
        bool CreateCaptureDevice(IMoniker mon)
        {
            object capObj = null;
            try
            {
                Guid gbf = typeof(IBaseFilter).GUID;
                mon.BindToObject(null, null, ref gbf, out capObj);
                capFilter = (IBaseFilter)capObj; capObj = null;
                return true;
            }
            catch (Exception ee)
            {
                MessageBox.Show(this, "Could not create capture device\r\n" + ee.Message, "DirectShow.NET", MessageBoxButtons.OK, MessageBoxIcon.Stop);
                return false;
            }
            finally
            {
                if (capObj != null)
                    Marshal.ReleaseComObject(capObj); capObj = null;
            }
        }        /// <summary>
        /// Luoz：创建使用COM组件的接口并获得
        /// </summary>
        /// <returns></returns>
        bool GetInterfaces()
        {
            Type comType = null;
            object comObj = null;
            try
            {
                comType = Type.GetTypeFromCLSID(Clsid.FilterGraph);
                if (comType == null)
                    throw new NotImplementedException(@"DirectShow FilterGraph not installed/registered!");
                comObj = Activator.CreateInstance(comType);
                graphBuilder = (IGraphBuilder)comObj; comObj = null;                //Guid clsid = Clsid.CaptureGraphBuilder2;
                //Guid riid = typeof(ICaptureGraphBuilder2).GUID;
                //comObj = DsBugWO.CreateDsInstance(ref clsid, ref riid);
                //capGraph = (ICaptureGraphBuilder2)comObj; comObj = null;                comType = Type.GetTypeFromCLSID(Clsid.CaptureGraphBuilder2);
                comObj = Activator.CreateInstance(comType);
                capGraph = (ICaptureGraphBuilder2)comObj; comObj = null;                mediaCtrl = (IMediaControl)graphBuilder;
                videoWin = (IVideoWindow)graphBuilder;
                mediaEvt = (IMediaEventEx)graphBuilder;
                return true;
            }
            catch (Exception ee)
            {
                MessageBox.Show(this, "Could not get interfaces\r\n" + ee.Message, "DirectShow.NET", MessageBoxButtons.OK, MessageBoxIcon.Stop);
                return false;
            }
            finally
            {
                if (comObj != null)
                    Marshal.ReleaseComObject(comObj); comObj = null;
            }
        }        /// <summary>
        /// "Luoz：打造捕捉图"
        /// </summary>
        /// <returns></returns>
        bool SetupGraph()
        {
            int hr;
            IBaseFilter mux = null;
            IFileSinkFilter sink = null;            try
            {
                hr = capGraph.SetFiltergraph(graphBuilder);
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                hr = graphBuilder.AddFilter(capFilter, "Ds.NET Video Capture Device");
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                DsUtils.ShowCapPinDialog(capGraph, capFilter, this.Handle);                Guid sub = MediaSubType.Avi;
                hr = capGraph.SetOutputFileName(ref sub, fileName, out mux, out sink);
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                Guid cat = PinCategory.Capture;
                Guid med = MediaType.Video;
                hr = capGraph.RenderStream(ref cat, ref med, capFilter, null, mux); // 流文件
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                cat = PinCategory.Preview;
                med = MediaType.Video;
                hr = capGraph.RenderStream(ref cat, ref med, capFilter, null, null); // 预览窗口
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                return true;
            }
            catch (Exception ee)
            {
                MessageBox.Show(this, "Could not setup graph\r\n" + ee.Message, "DirectShow.NET", MessageBoxButtons.OK, MessageBoxIcon.Stop);
                return false;
            }
            finally
            {
                if (mux != null)
                    Marshal.ReleaseComObject(mux); mux = null;
                if (sink != null)
                    Marshal.ReleaseComObject(sink); sink = null;
            }
        }        /// <summary>
        /// Luoz： 预览
        /// </summary>
        bool SetupVideoWindow()
        {
            int hr;
            try
            {
                // 设置视频窗口是主窗口的子窗口
                hr = videoWin.put_Owner(panel1.Handle);
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                // Set video window style
                hr = videoWin.put_WindowStyle(WS_CHILD | WS_CLIPCHILDREN);
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                //使用助手功能定位在客户端的视频窗口的所有者窗口矩形
                //ResizeVideoWindow();                // 使视频窗口可见，现在它已正确定位
                hr = videoWin.put_Visible(DsHlp.OATRUE);
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);                hr = mediaEvt.SetNotifyWindow(this.Handle, WM_GRAPHNOTIFY, IntPtr.Zero);
                if (hr < 0)
                    Marshal.ThrowExceptionForHR(hr);
                return true;
            }
            catch (Exception ee)
            {
                MessageBox.Show(this, "Could not setup video window\r\n" + ee.Message, "DirectShow.NET", MessageBoxButtons.OK, MessageBoxIcon.Stop);
                return false;
            }
        }    }
}