directshow应用开发的常用操作函数

获得一个filter的上游或者下游的filter：

static HRESULT GetNextFilter(IBaseFilter *pFilter,PIN_DIRECTION Dir,IBaseFilter **ppNext){if(!pFilter||!ppNext)return E_POINTER;IEnumPins *pEnum=0;IPin *pPin=0;HRESULT hr=pFilter->EnumPins(&pEnum);if(FAILED(hr))return hr;while(S_OK==pEnum->Next(1,&pPin,0)){PIN_DIRECTION ThisPinDir;hr=pPin->QueryDirection(&ThisPinDir);if(FAILED(hr)){hr=E_UNEXPECTED;//pPin->Release();SAFE_RELEASE(pPin);break;}if(ThisPinDir==Dir){IPin *pPinNext=0;hr=pPin->ConnectedTo(&pPinNext);if(SUCCEEDED(hr)){PIN_INFO PinInfo;hr=pPinNext->QueryPinInfo(&PinInfo);pPinNext->Release();pEnum->Release();if(FAILED(hr)||(PinInfo.pFilter==NULL)){return E_UNEXPECTED;}*ppNext=PinInfo.pFilter;return S_OK;}}pPin->Release();}pEnum->Release();return E_FAIL;}

枚举一个graph图中的所有filter：

static HRESULT EnumFilters(IFilterGraph *pGraph){//枚举Filter Graph 中的所有FilterIEnumFilters *pEnum=NULL;HRESULT hr=pGraph->EnumFilters(&pEnum);if(SUCCEEDED(hr)){IBaseFilter* pFilter=NULL;FILTER_INFO Filter_Info;CLSID m_clsd;while(S_OK==pEnum->Next(1, &pFilter,NULL)){//pGraph->RemoveFilter(pFilter);//删除Filter//pEnum->Reset();               //复位枚举器内部状态pFilter->QueryFilterInfo(&Filter_Info);pFilter->GetClassID(&m_clsd);//pFilter->Release();SAFE_RELEASE(pFilter);}//pEnum->Release();SAFE_RELEASE(pEnum);}return hr;}

在graphedit中动态显示应用程序中建的graph：

static HRESULT AddToRot(IUnknown *pUnkGraph, DWORD *pdwRegister){IMoniker * pMoniker;IRunningObjectTable *pROT;if (FAILED(GetRunningObjectTable(0, &pROT))) {return E_FAIL;}WCHAR wsz[256];wsprintfW(wsz, L"FilterGraph %08p pid %08x", (DWORD_PTR)pUnkGraph, GetCurrentProcessId());HRESULT hr = CreateItemMoniker(L"!", wsz, &pMoniker);if (SUCCEEDED(hr)) {hr = pROT->Register(0, pUnkGraph, pMoniker, pdwRegister);//pMoniker->Release();SAFE_RELEASE(pMoniker);}//pROT->Release();SAFE_RELEASE(pROT);return hr;}static void AddToObjectTable(IUnknown *pUnkGraph, DWORD *pdwRegister){IMoniker * pMoniker = 0;IRunningObjectTable * objectTable = 0;if (SUCCEEDED(GetRunningObjectTable(0, &objectTable))) {WCHAR wsz[256];wsprintfW(wsz, L"FilterGraph %08p pid %08x", (DWORD_PTR)pUnkGraph, GetCurrentProcessId());HRESULT hr = CreateItemMoniker(L"!", wsz, &pMoniker);if (SUCCEEDED(hr)) {hr = objectTable->Register(0, pUnkGraph, pMoniker, pdwRegister);//pMoniker->Release();SAFE_RELEASE(pMoniker);}//objectTable->Release();SAFE_RELEASE(objectTable);}}

保存你所创建的graph：

static HRESULT SaveGraphFile(IGraphBuilder *pGraph, WCHAR *wszPath) {const WCHAR wszStreamName[] = L"ActiveMovieGraph"; HRESULT hr;IStorage *pStorage = NULL;hr = StgCreateDocfile(wszPath,STGM_CREATE | STGM_TRANSACTED | STGM_READWRITE | STGM_SHARE_EXCLUSIVE,0, &pStorage);if(FAILED(hr)) {return hr;}IStream *pStream;hr = pStorage->CreateStream(wszStreamName,STGM_WRITE | STGM_CREATE | STGM_SHARE_EXCLUSIVE,0, 0, &pStream);if (FAILED(hr)) {SAFE_RELEASE(pStorage); return hr;}IPersistStream *pPersist = NULL;pGraph->QueryInterface(IID_IPersistStream, (void**)&pPersist);hr = pPersist->Save(pStream, TRUE);SAFE_RELEASE(pStream);SAFE_RELEASE(pPersist);if (SUCCEEDED(hr)) {hr = pStorage->Commit(STGC_DEFAULT);}SAFE_RELEASE(pStorage);return hr;}