DirectShow 切割视频保存到本地

DES对于视频的拼接和拼接后视频的预览书上都有讲到，但是对于拼接后视频保存到本地的代码却是哪也找不到（自己搜索过很久）

保存到本地的关键一段代码就是找到压缩器，这段代码书上只说了大概的思路，如果你不使用压缩器直接用书上的代码的话，截取下来的视频画面将严重失真。

void CXunLeiPlayDlg::WriteFile(IAMTimeline *pTL){IRenderEngine *pRenderEngine=NULL;CoCreateInstance(CLSID_RenderEngine,NULL,CLSCTX_INPROC_SERVER,IID_IRenderEngine ,(void**)&pRenderEngine);IMediaControl   *pMC=NULL; IMediaEvent     *pEvent=NULL; IGraphBuilder   *pGraph; ICaptureGraphBuilder2   *pBuilder=NULL;HRESULT hr=pRenderEngine->SetTimelineObject(pTL);hr=pRenderEngine->ConnectFrontEnd();hr=pRenderEngine->GetFilterGraph(&pGraph);hr=CoCreateInstance(CLSID_CaptureGraphBuilder2, NULL, CLSCTX_INPROC, IID_ICaptureGraphBuilder2, (void   **)&pBuilder); ASSERT(SUCCEEDED(hr)); hr=pBuilder->SetFiltergraph(pGraph); ASSERT(SUCCEEDED(hr)); IBaseFilter *pMux; hr=pBuilder->SetOutputFileName(&MEDIASUBTYPE_Avi,L"流年逝水.avi",&pMux,NULL); ASSERT(SUCCEEDED(hr)); long NumGroups; pTL->GetGroupCount(&NumGroups); for   (int i=0;i<NumGroups;i++) { IPin  *pPin=NULL; if   (pRenderEngine->GetGroupOutputPin(i,&pPin)==S_OK) { IBaseFilter *pCompressor=NULL;pCompressor=GetCompressor(CLSID_VideoCompressorCategory,"Microsoft Video 1"); //获取压缩器pGraph->AddFilter(pCompressor,L"com");//加入过滤器hr=pBuilder->RenderStream(NULL,NULL,pPin,pCompressor,pMux); ASSERT(SUCCEEDED(hr));pPin->Release(); } } pGraph->QueryInterface(IID_IMediaEvent,(void**)&pEvent); pGraph->QueryInterface(IID_IMediaControl,(void**)&pMC); pMC->Run(); long evCode;pEvent->WaitForCompletion(INFINITE,&evCode);pMC->Stop();}IBaseFilter* CXunLeiPlayDlg::GetCompressor(GUID inCategory, const char *inFriendlyName){ICreateDevEnum * enumHardware = NULL;HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum,NULL,CLSCTX_ALL,IID_ICreateDevEnum, (void**)&enumHardware);if (FAILED(hr)){return NULL;}IBaseFilter * hardwareFilter = NULL;IEnumMoniker * enumMoniker   = NULL;hr = enumHardware->CreateClassEnumerator(inCategory,&enumMoniker,0);if (enumMoniker){enumMoniker->Reset();ULONG      fetched = 0;IMoniker * moniker = NULL;char friendlyName[256];while (!hardwareFilter &&SUCCEEDED(enumMoniker->Next(1,&moniker,&fetched))&&fetched){if (moniker){IPropertyBag * propertyBag = NULL;VARIANT        name;friendlyName[0] = 0;hr = moniker->BindToStorage(0,0,IID_IPropertyBag,(void **)&propertyBag);if (SUCCEEDED(hr)){name.vt=VT_BSTR;hr = propertyBag->Read(L"FriendlyName",&name,NULL);}if (SUCCEEDED(hr)){WideCharToMultiByte(CP_ACP, 0, name.bstrVal, -1,friendlyName, 256, NULL, NULL);if (strcmp(friendlyName,inFriendlyName) == 0) {moniker->BindToObject(0, 0, IID_IBaseFilter, (void**)&hardwareFilter);}}if (propertyBag){propertyBag->Release();propertyBag = NULL;}moniker->Release();}}enumMoniker->Release();}enumHardware->Release();return hardwareFilter;}