directshow实现了视频采集,怎样保存?该如何解决

[color=#FF0000] //采集相关的变量[/color]
    IGraphBuilder *pGraph;    
    ICaptureGraphBuilder2 *pBuild; //视频采集过滤器图表
         IMediaControl *m_pMediaControl;
    //视频采集设备的源Filter   
    IBaseFilter* pSrc;
[color=#FF0000]//---------------------------------//[/color]

HRESULT hr;
    //创建IGraphBuilder
    CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC, IID_IGraphBuilder, (void      **)&pGraph);

    //创建ICaptureGraphBuilder2
    hr = CoCreateInstance(CLSID_CaptureGraphBuilder2, NULL, 
        CLSCTX_INPROC_SERVER, IID_ICaptureGraphBuilder2, (void**)&pBuild); 

    // 过滤器图表添加到管理器中
    pBuild->SetFiltergraph(pGraph); 

    pGraph->QueryInterface(IID_IVideoWindow, (void **)&m_pVidWin);
[color=#FF0000]//--------------------------------------------//
//以下代码为查找设备[/color]
    ICreateDevEnum *pDevEnum=NULL;
    IEnumMoniker *pClsEnum=NULL;

    //创建设备枚举COM对象
    CoCreateInstance(CLSID_SystemDeviceEnum,NULL,CLSCTX_INPROC,IID_ICreateDevEnum,(void **)&pDevEnum);

    //创建视频采集设备枚举COM对象
    pDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory,&pClsEnum,0);
    if(pClsEnum == NULL)
    {
        MessageBox(_T("Sorry, you have no video capture hardware.\r\n\r\nVideo capture will not function properly."));
        //如果没有设备，返回
        return ; 
    } 

    IMoniker *pMoniker = NULL;
    //如果先前的createclassenumerator调用成功了，可以用ienummoniker::next得到设备
    if(pClsEnum->Next(1,&pMoniker,NULL)==S_OK)
    {
        //调用imoniker::bindtoobject建立一个和选择的device联合的filter
        pMoniker->BindToObject(0,0,IID_IBaseFilter,(void **)&pSrc);
        pMoniker->Release();
    }

    //将设备添加到管理器graph
    hr = pGraph->AddFilter(pSrc, L"Video Capture");
[color=#FF0000]//---------------------------------------
//视频开始采集----------------------------//[/color]
    //连接一个源插口,将Filter添加到过滤器图表中
    hr=pBuild->RenderStream(&PIN_CATEGORY_CAPTURE,&MEDIATYPE_Video,pSrc,NULL,NULL); 

    //设定视频窗口为主窗口的一个子窗口
    m_pVidWin->put_Owner((OAHWND)m_hWnd);
    m_pVidWin->put_WindowStyle(WS_CHILD | WS_CLIPSIBLINGS | WS_CLIPCHILDREN);
    CRect rc;
    GetDlgItem(IDC_VW_FRAME)->GetWindowRect(rc);
    ScreenToClient(rc);

    //设定视频窗口
    m_pVidWin->SetWindowPosition(rc.left, rc.top, rc.Width(), rc.Height());

    hr=pGraph->QueryInterface(IID_IMediaControl, (void **)&m_pMediaControl);

    hr=m_pMediaControl->Run();    //运行Filter Graph
    if(FAILED(hr))
    {
        MessageBox(_T("加载运行失败！"));  
        return ;
    }