DirectShow删除链路 和 删除graph中的所有filter

一般应用DirectShow的时候，我们会封装一个类。

一般情况下，如果摄像头被占用，就无法再次开启。

这里举个例子，如：

在类中声明主要变量；

清理变量；

CCaptureCam

{

IGraphBuilder*
m_pGraphBuilder;

IFilterGraph* m_pFilterGraph;

ICaptureGraphBuilder2 * m_pCaptureGraphBuilder2;

IMediaControl * m_pMediaControl;

IVideoWindow * m_pVideoWindow;

IMediaSeeking * m_pMediaSeeking;

IBaseFilter * m_pSrcFilter;

IBaseFilter * m_pRenderFilter;

IBasicVideo *
m_pBasicVideo;

IBaseFilter *
m_pGrabber;

IMediaEvent * m_pMediaEvent;

IAMVideoProcAmp *
m_pProcAmp;

~CCaptureVideo()

{

//假定变量已经创建，链路已经建立运行；

//删除链路中的所有Filter；

// Stop the graph.

m_pMediaControl->Stop();

// Enumerate the filters in the graph.

IEnumFilters *pEnum = NULL;

hr = m_pGraphBuilder->EnumFilters(&pEnum);

if (SUCCEEDED(hr))

{

IBaseFilter *pFilter = NULL;

while (S_OK == pEnum->Next(1, &pFilter, NULL))

{

// Remove the filter.

m_pGraphBuilder->RemoveFilter(pFilter);

// Reset the enumerator.

pEnum->Reset();

pFilter->Release();

}

pEnum->Release();

}

//释放变量资源；如果仅仅释放资源，上述中的Filter和链路没有被删；

if(m_pMediaControl)

{

m_pMediaControl->Release();

m_pMediaControl=NULL;

}

if(m_pMediaEvent)

{

m_pMediaEvent->Release();

m_pMediaEvent=NULL;

}

if(m_pVideoWindow)

{

m_pVideoWindow->Release();

m_pVideoWindow = NULL;

}

if(m_pBasicVideo)

{

m_pBasicVideo->Release();

m_pBasicVideo = NULL;

}

if(m_pMediaSeeking)

{

m_pMediaSeeking->Release();

}

if(m_pSrcFilter)

{

m_pSrcFilter->Release();

}

if(m_pRenderFilter)

{

m_pRenderFilter->Release();

}

if(m_pGrabber)

{

m_pGrabber->Release();

}

if(m_pProcAmp)

{

m_pProcAmp->Release();

}

}

}