DirectShow .Net 实现视频

实例引用DirectShowLib-2005.dll，这个DLL可以到http://directshownet.sourceforge.net/直接下载使用。

1、获取视频采集设备IBaseFilter接口对象的方法

//获取所有视频设备名称public ArrayList GetVideoInputDevice()      { return GetDeviceCollection(FilterCategory.VideoInputDevice);}private ArrayList GetDeviceCollection(Guid DeviceType)      {          ArrayList returnString = new ArrayList();          foreach (DsDevice ds in DsDevice.GetDevicesOfCat(DeviceType))          {              returnString.Add(ds.Name);          }          return returnString;      }//通过获取到的视频设备名称设置采集设备的IBaseFilter对象 public bool SetVideoInputDevice(string VideoInputDeviceName)      {    //创建视频输入设备接口          theVideoDevice = CreateFilter(FilterCategory.VideoInputDevice, VideoInputDeviceName);       }//通过过滤器类型和过滤器名称获取IBaseFilter接口private IBaseFilter CreateFilter(Guid category, string friendlyname)      {          object source = null;          Guid iid = typeof(IBaseFilter).GUID;          foreach (DsDevice device in DsDevice.GetDevicesOfCat(category))          {              if (device.Name.CompareTo(friendlyname) == 0)              {                  device.Mon.BindToObject(null, null, ref iid, out source);                  break;              }          }

          return (IBaseFilter)source;      }

2、初始化基本的接口对象 

private void InitInterfaces()      {          int hr = 0;

          // 获取IGraphBuilder接口对象          this.m_graphBuilder = (IGraphBuilder)new FilterGraph();          //获取ICaptureGraphBuilder2接口对象          this.m_captureGraphBuilder = (ICaptureGraphBuilder2)new CaptureGraphBuilder2();          //获取m_graphBuilder 接口对象的IMediaControl对象          this.m_mediaControl = (IMediaControl)this.m_graphBuilder;          //获取m_graphBuilder 接口对象的IVideoWindow对象          this.m_videoWindow = (IVideoWindow)this.m_graphBuilder;          //获取m_graphBuilder 接口对象的IMediaEventEx对象          this.m_mediaEventEx = (IMediaEventEx)this.m_graphBuilder;          //设置ICaptureGraphBuilder2的IGraphBuilder接口对象为当前对象          hr = this.m_captureGraphBuilder.SetFiltergraph(this.m_graphBuilder);          DsError.ThrowExceptionForHR(hr);          //注册事件到应用程序的窗体上          hr = this.m_mediaEventEx.SetNotifyWindow(this.hwnPropertyPageOwner, WM_GRAPHNOTIFY, IntPtr.Zero);          DsError.ThrowExceptionForHR(hr);      }

 

 

 

3、开始视频预览public void VideoPreview()       try      {

          int hr = 0;                            hr = this.m_graphBuilder.AddFilter(theVideoDevice, "Video Capture");          DsError.ThrowExceptionForHR(hr);

          // 通过theVideoDevice（IBaseFilter）视频接口对象的Preview Pin预览          hr = this.m_captureGraphBuilder.RenderStream(PinCategory.Preview, MediaType.Video, theVideoDevice, null, null);          DsError.ThrowExceptionForHR(hr);

           //插入SampleGrabber           m_pinStill = DsFindPin.ByCategory(theVideoDevice, PinCategory.Still, 0);

          if (m_pinStill == null)              {                  m_pinStill = DsFindPin.ByCategory(theVideoDevice, PinCategory.Capture, 0);              }

              // 获取theVideoDevice的IAMVideoControl对象，对于具有Still Pin的对象可以获到，采集设备不具备Still Pin，那么该对象将为Null              m_VidControl = theVideoDevice as IAMVideoControl;

              // 设置采集视频参数              if (this.videoHeight + this.videoWidth + this.videoStride > 0)              {                  SetConfigParms(m_pinStill, this.videoWidth, this.videoHeight, 24);              }

             //开始拍照功能所需的接口对象              // 获得SampleGrabber对象接口              sampGrabber = new SampleGrabber() as ISampleGrabber;

              // 配置sample grabber              baseGrabFlt = sampGrabber as IBaseFilter;              ConfigureSampleGrabber(sampGrabber);

              // 将sample grabber添加到图形过滤器中              hr = m_graphBuilder.AddFilter(baseGrabFlt, "Ds.NET Grabber");              DsError.ThrowExceptionForHR(hr);

              //通过渲染将采集设备的相关输出Pin与sample grabber对象的输入Pin连接起来              //如果采集设备提供Still Pin，则通过Still Pin连接，否则直接使用Capture Pin连接              if (m_VidControl!=null)              {                  hr = this.m_captureGraphBuilder.RenderStream(PinCategory.Still, MediaType.Video, theVideoDevice, null, baseGrabFlt);                  DsError.ThrowExceptionForHR(hr);

              }              else              {                  hr = this.m_captureGraphBuilder.RenderStream(PinCategory.Capture, MediaType.Video, theVideoDevice, null, baseGrabFlt);                  DsError.ThrowExceptionForHR(hr);              }            //设置抓取图片相关参数              SaveSizeInfo(sampGrabber);            //拍照功能所需的接口对象添加结束

          // 开始将视频窗口绑定到主窗体上          hr = this.m_videoWindow.put_Owner(this.hwnVideoWindowOwner);          DsError.ThrowExceptionForHR(hr);

          hr = this.m_videoWindow.put_WindowStyle(WindowStyle.Child | WindowStyle.ClipChildren);          DsError.ThrowExceptionForHR(hr);

          if (this.m_videoWindow != null)          {              this.m_videoWindow.SetWindowPosition(0, 0, this.videoWidth, this.videoHeight);          }

          hr = this.m_videoWindow.put_Visible(OABool.True);          DsError.ThrowExceptionForHR(hr);

          // 开始预览采集设备采集到的视频          hr = this.m_mediaControl.Run();

          DsError.ThrowExceptionForHR(hr);          m_IsPreview = true;      }      catch          {          m_IsPreview = false;          throw new Exception("VideoPreview函数出现异常，视频预览失败！");              }      }