DirectShow .Net 实现视频

DirectShow .Net 实现视频

 、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) == )
               {
                   device.Mon.BindToObject(null, null, ref iid, out source);
                   break;
               }
           }

           return (IBaseFilter)source;
       }

 、初始化基本的接口对象 

 private void InitInterfaces()
       {
           int hr = ;

           // 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);
       }

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

           int hr = ;
           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, );

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

               // 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 > )
               {
                   SetConfigParms(m_pinStill, this.videoWidth, this.videoHeight, );
               }

              //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(, , 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！");

       }
       }