DirectShow3

\如何修改系统中已经注册的Filter的Merit值
typedef struct
{
 DWORD dwVersion; //版本号
 DWORD dwMerit;  //Merit值
 DWORD dwPinCount; //Pin的数量
 DWORD dwReserved; //保留
}FILTER_HEADER;

BOOL SetFilterMerit(const char*inClsid,DWORD inMerit)
{
 const char* cRegistryEntry="CLSID\{083863F1-70DE-11d0-BD40-00A0C911CE86}\Instance\";
 const long cMaxLength=1024*16;
 BYTE filterData[cMaxLength];
 DWORD actualLength=0;
 \生成Filter信息注册部分的注册表入口
 char szEntry[1000];
 strcpy(szEntry,cRegistryEntry);
 strcat(szEntry,inClsid);
 HKEY hKey=NULL;
 LONG result=::RegOpenKeyEx(HKEY_CLASSES_ROOT,szEntry,0,KEY_ALL_ACCESS,&hKey);
 BOOL pass=(result==ERROR_SUCCESS);
 if(pass)
 {
  \读取FilterData的值
  actualLength=actualLength;
  result=::RegQueryValueEx(hKey,"FilterData",NULL,NULL,filterData,&actualLength);
  pass=(result==ERROR_SUCCESS);
 }
 if(pass)
 {
  \修改FiterData中的Merit部分，然后写回到注册表
  FILTER_HEADER *filterHeader=(FILTER_HEADER *)filterData;
  filterHeader->dwMerit=inMerit;
  result=::RegSetValueEx(hKey,"FilterData",NULL,REG_BINARy,filterData,actualLength);
  pass=(result==ERROR_SUCCESS);
 }
 if(hKey)
 {
  ::RegCloseKey(hKey);
 }
 return pass;
}

 

STDMETHODIMP CBaseInputPin::Receive(IMediaSample *pSample)
{
 CheckPointer(pSample,E_POINTER);
 ValidateReadPtr(pSample,sizeof(IMediaSample));
 ASSERT(pSample);
 \检查Filter内部状态，以及数据流传送状态
 HRESULT hr=CheckStreaming();
 if(S_OK!=hr)
 {
  return hr;
 }
 \查询IMediaSample2接口，获取输入Sample上的属性
 IMediaSample2 *pSample2;
 if(SUCCEEDED(pSample->QueryInterface(IID_IMediaSample2,(void **)&pSample2)))
 {
  hr=pSample2->GetProperties(sizeof(m_SampleProps),(PBYTE)&m_SampleProps);
  pSample2->Release();
  if(FAILED(hr))
  {
   return hr;
  }
 }
 else
 {
  \使用ImediaSample接口获取输入Sample上的属性
  m_SampleProps.cbData=sizeof(m_SampleProps);
  m_SampleProps.dwTypeSpecificFlags=0;
  m_SampleProps.dwStreamId=AM_STREAM_MEDIA;
  m_SampleProps.dwSampleFlags=0;
  if(S_OK==pSample->IsDiscontinuity())
  {
   m_SampleProps.dwSampleFlags|=AM_SAMPLE_DATADISCONTINUITY;
  }
  if(S_OK==pSample->IsPreroll())
  {
   m_SampleProps.dwSampleFlags|=AM_SAMPLE_PREROLL;
  }
  if(S_OK==pSample->IsSyncPoint())
  {
   m_SampleProps.dwSampleFlags|=AM_SAMPLE_SPLICEPOINT;
  }
  if(SUCCEEDED(pSample->GetTime(&m_SampleProps.tStart,&m_SampleProps.tStop)))
  {
   m_SampleProps.dwSampleFlags|=AM_SAMPLE_TIMEVALID|AM_SAMPLE_STOPVALID;
  }
  if(S_OK==pSample->GetMediaType(&m_SampleProps.pMediaType))
  {
   m_SampleProps.dwSampleFlags|=AM_SAMPLE_TYPECHANGED;
  }
  pSample->GetPointer(&m_SampleProps.pbBuffer);
  m_SampleProps.lActual=pSample->GetActualDataLength();
  m_SampleProps.cbBuffer=pSample->GetSize();
 }
 \检测Sample上的媒体类型是否改变
 if(!(m_SampleProps.dwSampleFlags&AM_SAMPLE_TYPECHANGED))
 {
  return NOERROR;
 }
 \检查输入Pin上是否支持这种新的媒体类型。此时，输入Pin应该是支持这种媒体类型
 \的，因为上一级Filter在做出这种媒体类型的动态改变之前，一般会先调用输入Pin
 \上的IPin::QueryAccept接口方法进行确认
 hr=CheckMediaType((CMediaType *)m_SampleProps.pMediaType);
 if(hr==NOERROR)
 {
  return NOERROR;
 }
 m_bRunTimeError=TRUE;
 EndOfStream();
 m_pFilter->NotifyEvent(EC_ERRORABORT,VFN_E_TYPE_NOT_ACCEPTED,0);
 return VFW_E_INVALIDMEDIATYPE; 
}