directshow,filter: 什么時候調用 m_pGraphBuilder->RemoveFilter

code如下： 如果用下列函數，調用系統自帶的File Source，就無需 調用 m_pGraph->RemoveFilter，只要

調用 pFIFileSource->release();就可以了。

但是，如果不是系統的，必需用m_pGraphBuilder->RemoveFilter（），否則，filter的析構函數不會被調

用。

if (SUCCEEDED(hr)) 
  hr = CoCreateInstance(CLSID_AsyncSample, NULL, CLSCTX_INPROC,
        IID_IBaseFilter, (LPVOID *)

&pFIFileSource) ;
 if (SUCCEEDED(hr))
  hr = m_pGraphBuilder->AddFilter(pFIFileSource,L"Sample File Source");

 IFileSourceFilter *pAVIFileSource = NULL;

 if (SUCCEEDED(hr)) 
  hr = pFIFileSource->QueryInterface(IID_IFileSourceFilter,(void **)

&pAVIFileSource);

同樣：
if (SUCCEEDED(hr)) 
  hr = CoCreateInstance(CLSID_MYSocketSource, NULL, CLSCTX_INPROC,
        IID_IBaseFilter, (LPVOID *)

&pFIFileSource) ;
 if (SUCCEEDED(hr))
  hr = m_pGraphBuilder->AddFilter(pFIFileSource,L"MY Socket Source");

...
最后必需用m_pGraphBuilder->RemoveFilter（），否則，filter的析構函數不會被調用。否則有很大的內

存泄露。

不知道是什么原因：

因為  www.directshow.cn： 這個網址不行了，所以貼出下列code，請大家分享。


HRESULT ConnectPins( IGraphBuilder* pGraphBuilder,
     IBaseFilter* pOutput,
     IBaseFilter* pInput,
     int nOutIndex,
     int nInIndex)
{
 HRESULT hr = NOERROR;
 ULONG cFetched = 0;
 IEnumPins* pEnumPins = 0;
 IPin* pPinOutput = 0;
 IPin* pPinInput = 0;

 //enum output filter pins.
 hr = pOutput->EnumPins(&pEnumPins);
 if(FAILED(hr))
 {
  return hr;
 }
 //if the pin to connect is not the first one, we must skip nOutIndex-1 pins.
 if(nOutIndex>1)
 {
  hr = pEnumPins->Skip(nOutIndex-1);
  if(FAILED(hr))
  {
   pEnumPins->Release();
   return hr;
  }
 }
 //now we can get the output pin we wanted.
 hr = pEnumPins->Next(1,&pPinOutput,&cFetched);
 if(FAILED(hr))
 {
  pEnumPins->Release();
  return hr;
 }
 pEnumPins->Release();

 //enum input filter pins.
 hr = pInput->EnumPins(&pEnumPins);
 if(FAILED(hr))
 {
  pPinOutput->Release();
  return hr;
 }
 //if input pin is not the first to connect, we must skip nInIndex-1 pins.
 if(nInIndex>1)
 {
  hr = pEnumPins->Skip(nInIndex-1);
  if( FAILED(hr) )
  {
   pPinOutput->Release();
   pEnumPins->Release();
   return hr;
  }
 }
 //now we can get the input pin we wanted.
 hr = pEnumPins->Next(1,&pPinInput,&cFetched);
 if(FAILED(hr))
 {
  pPinOutput->Release();
  pEnumPins->Release();
  return hr;
 }
 pEnumPins->Release();

 //now connect from output pin to input pin.
 hr = pGraphBuilder->Connect(pPinOutput,pPinInput);
 pPinOutput->Release();
 pPinInput->Release();
 return hr;
}
IPin* xMyFindPin(IBaseFilter *pFilter, const WCHAR achName[])
{
 BOOL       bFound = FALSE;
 IEnumPins  *pEnum;
 IPin       *pPin;
 PIN_INFO pininfo;

 if(pFilter==NULL)
  return NULL;
 pFilter->EnumPins(&pEnum);
 while(pEnum->Next(1, &pPin, 0) == S_OK)
 {
  pPin->QueryPinInfo(&pininfo);
  pininfo.pFilter->Release();
  if (bFound = (0 == wcscmp(pininfo.achName,achName)))
   break;
  pPin->Release();
 }
 pEnum->Release();
 return (bFound ? pPin : 0); 
}
static const GUID  CLSID_NULL_USER1=
{0x00000000, 0x0000, 0x0000, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

HRESULT GetUnconnectedPin( IBaseFilter *pFilter,
        PIN_DIRECTION PinDir,
        IPin **ppPin,GUID gMajortype,WCHAR *achName)
{
 *ppPin = 0;
 IEnumPins *pEnum = 0;
 IPin *pPin = 0;
 HRESULT hr = pFilter->EnumPins( &pEnum );
 if( FAILED( hr ) )
 {
  return hr;
 }
 while( pEnum->Next( 1, &pPin, NULL ) == S_OK )
 {
  PIN_DIRECTION ThisPinDir;
  pPin->QueryDirection( &ThisPinDir );
  if( ThisPinDir == PinDir )
  {
   IPin *pTmp = 0;
   hr = pPin->ConnectedTo( &pTmp );
   if( SUCCEEDED( hr ) )
   {
    pTmp->Release( );
   }
   else
   {    
    PIN_INFO pininfo;
    pPin->QueryPinInfo(&pininfo);
    pininfo.pFilter->Release();
    if(achName && (wcslen(achName)>= wcslen(pininfo.achName)))
     wcscpy(achName,pininfo.achName);

    if(gMajortype==CLSID_NULL_USER1)
    {
     pEnum->Release( );
     *ppPin = pPin;
     return S_OK;
    }
    else
    {
     IEnumMediaTypes* pTypeEnum;
     hr = pPin->EnumMediaTypes (&pTypeEnum);

     hr =pTypeEnum->Reset();
     AM_MEDIA_TYPE* pMediaType;
     ULONG            ul ;

     do
     {
      hr = pTypeEnum->Next(1, &pMediaType, &ul) ;
      if (FAILED(hr) || 0 == ul)
      {
       pTypeEnum->Release();
       //pEnum->Release( );
       if(pTmp)
        pTmp->Release();
       break ;
      }

      if (pMediaType->majortype == gMajortype)
      // ||       pMediaType->subtype == MEDIASUBTYPE_DVSD)
      { pTypeEnum->Release();
       pEnum->Release( );
       *ppPin = pPin;
       return S_OK;
      }
     }while (1) ;   

    }
   }
   if(pTmp)
    pTmp->Release();
  }
  pPin->Release( );
 }
 pEnum->Release( );

 return E_FAIL;
}