DirectShow：networking摄像头预览和图像捕捉

看了一个非常类似的问题，看到几乎相同的代码，我决定单独提出这个问题。 我想将networking摄像机videostream的video预览显示在DirectShow使用的默认窗口中，而且我还希望能够在任何特定时刻“拍照”videostream。

我开始使用MSDN上的DirectShow示例，以及AMCap示例代码，并且我相信应该是预览部分，但是不应该。 我没有发现从videostream中抓取图像的例子，除了使用SampleGrabber，这是弃用，因此我试图不使用它。

下面是我的代码，行代码。 请注意，EnumerateCameras中的大部分代码都被注释掉了。 该代码将被附加到另一个窗口，我不想这样做。 在MSDN文档中，它明确指出VMR_7创build自己的窗口来显示videostream。 我的应用程序没有出现错误，但是此窗口从不出现。

我的问题是这样的：我在做什么错了？ 或者，如果您知道我正在尝试做的一个简单示例，请将其链接到我。 AMCap不是一个简单的例子，仅供参考。

• Windows上C库的二进制交叉编译器兼容性
• 如何获得当前帧？
• 我怎样才能模拟使用Win32挂钩的Alt + Tab？
• GetAsyncKeyState用cin创build问题
• Web和桌面应用程序之间良好的沟通方式

注意：InitalizeVMR是在无窗口状态下运行的，这是我的最终目标（集成到DirectX游戏中）。 但是，现在我只想让它以最简单的模式运行。

编辑：这个问题的第一部分，即预览相机stream，解决了。 我现在只是寻找替代弃用的SampleGrabber类，所以我可以随时拍摄一张照片，并将其保存到一个文件。

编辑：在谷歌上找了差不多一个小时之后，总体上的一致似乎是你必须使用ISampleGrabber。 如果你发现有什么不同，请告诉我。

testing代码（main.cpp）：

CWebcam* camera = new CWebcam(); HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED); MessageBox(NULL, L"text", L"caption", NULL); if (SUCCEEDED(hr)) { camera->Create(); camera->EnumerateCameras(); camera->StartCamera(); } int d; cin >> d; 

Webcam.cpp：

 #include "Webcam.h" CWebcam::CWebcam() { HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED); //m_pTexInst = nullptr; //m_pTexRes = nullptr; } CWebcam::~CWebcam() { CoUninitialize(); m_pDeviceMonikers->Release(); m_pMediaController->Release(); } BOOL CWebcam::Create() { InitCaptureGraphBuilder(&m_pFilterGraph, &m_pCaptureGraph); hr = m_pFilterGraph->QueryInterface(IID_IMediaControl, (void **)&m_pMediaController); return TRUE; } void CWebcam::Destroy() { } void CWebcam::EnumerateCameras() { HRESULT hr = EnumerateDevices(CLSID_VideoInputDeviceCategory, &m_pDeviceMonikers); if (SUCCEEDED(hr)) { //DisplayDeviceInformation(m_pDeviceMonikers); //m_pDeviceMonikers->Release(); IMoniker *pMoniker = NULL; if(m_pDeviceMonikers->Next(1, &pMoniker, NULL) == S_OK) { hr = pMoniker->BindToObject(0, 0, IID_IBaseFilter, (void**)&m_pCameraFilter); if (SUCCEEDED(hr)) { hr = m_pFilterGraph->AddFilter(m_pCameraFilter, L"Capture Filter"); } } // connect the output pin to the video renderer if(SUCCEEDED(hr)) { hr = m_pCaptureGraph->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, m_pCameraFilter, NULL, NULL); } //InitializeVMR(hwnd, m_pFilterGraph, &m_pVMRControl, 1, FALSE); //get the video window that will be displayed from the filter graph IVideoWindow *pVideoWindow = NULL; hr = m_pFilterGraph->QueryInterface(IID_IVideoWindow, (void **)&pVideoWindow); /*if(hr != NOERROR) { printf("This graph cannot preview properly"); } else { //get the video stream configurations hr = m_pCaptureGraph->FindInterface(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Video, m_pCameraFilter, IID_IAMStreamConfig, (void **)&m_pVideoStreamConfig); //Find out if this is a DV stream AM_MEDIA_TYPE *pMediaTypeDV; //fake window handle HWND window = NULL; if(m_pVideoStreamConfig && SUCCEEDED(m_pVideoStreamConfig->GetFormat(&pMediaTypeDV))) { if(pMediaTypeDV->formattype == FORMAT_DvInfo) { // in this case we want to set the size of the parent window to that of // current DV resolution. // We get that resolution from the IVideoWindow. IBasicVideo* pBasivVideo; // If we got here, gcap.pVW is not NULL //ASSERT(pVideoWindow != NULL); hr = pVideoWindow->QueryInterface(IID_IBasicVideo, (void**)&pBasivVideo); /*if(SUCCEEDED(hr)) { HRESULT hr1, hr2; long lWidth, lHeight; hr1 = pBasivVideo->get_VideoHeight(&lHeight); hr2 = pBasivVideo->get_VideoWidth(&lWidth); if(SUCCEEDED(hr1) && SUCCEEDED(hr2)) { ResizeWindow(lWidth, abs(lHeight)); } } } } RECT rc; pVideoWindow->put_Owner((OAHWND)window); // We own the window now pVideoWindow->put_WindowStyle(WS_CHILD); // you are now a child GetClientRect(window, &rc); pVideoWindow->SetWindowPosition(0, 0, rc.right, rc.bottom); // be this big pVideoWindow->put_Visible(OATRUE); }*/ } } BOOL CWebcam::StartCamera() { if(m_bIsStreaming == FALSE) { m_bIsStreaming = TRUE; hr = m_pMediaController->Run(); if(FAILED(hr)) { // stop parts that ran m_pMediaController->Stop(); return FALSE; } return TRUE; } return FALSE; } void CWebcam::EndCamera() { if(m_bIsStreaming) { hr = m_pMediaController->Stop(); m_bIsStreaming = FALSE; //invalidate client rect as well so that it must redraw } } BOOL CWebcam::CaptureToTexture() { return TRUE; } HRESULT CWebcam::InitCaptureGraphBuilder( IGraphBuilder **ppGraph, // Receives the pointer. ICaptureGraphBuilder2 **ppBuild // Receives the pointer. ) { if (!ppGraph || !ppBuild) { return E_POINTER; } IGraphBuilder *pGraph = NULL; ICaptureGraphBuilder2 *pBuild = NULL; // Create the Capture Graph Builder. HRESULT hr = CoCreateInstance(CLSID_CaptureGraphBuilder2, NULL, CLSCTX_INPROC_SERVER, IID_ICaptureGraphBuilder2, (void**)&pBuild ); if (SUCCEEDED(hr)) { // Create the Filter Graph Manager. hr = CoCreateInstance(CLSID_FilterGraph, 0, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void**)&pGraph); if (SUCCEEDED(hr)) { // Initialize the Capture Graph Builder. pBuild->SetFiltergraph(pGraph); // Return both interface pointers to the caller. *ppBuild = pBuild; *ppGraph = pGraph; // The caller must release both interfaces. return S_OK; } else { pBuild->Release(); } } return hr; // Failed } HRESULT CWebcam::EnumerateDevices(REFGUID category, IEnumMoniker **ppEnum) { // Create the System Device Enumerator. ICreateDevEnum *pSystemDeviceEnumerator; HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pSystemDeviceEnumerator)); if (SUCCEEDED(hr)) { // Create an enumerator for the category. hr = pSystemDeviceEnumerator->CreateClassEnumerator(category, ppEnum, 0); if (hr == S_FALSE) { hr = VFW_E_NOT_FOUND; // The category is empty. Treat as an error. } pSystemDeviceEnumerator->Release(); } return hr; } void CWebcam::DisplayDeviceInformation(IEnumMoniker *pEnum) { IMoniker *pMoniker = NULL; int counter = 0; while (pEnum->Next(1, &pMoniker, NULL) == S_OK) { IPropertyBag *pPropBag; HRESULT hr = pMoniker->BindToStorage(0, 0, IID_PPV_ARGS(&pPropBag)); if (FAILED(hr)) { pMoniker->Release(); continue; } VARIANT var; VariantInit(&var); // Get description or friendly name. hr = pPropBag->Read(L"Description", &var, 0); if (FAILED(hr)) { hr = pPropBag->Read(L"FriendlyName", &var, 0); } if (SUCCEEDED(hr)) { printf("%d: %S\n", counter, var.bstrVal); VariantClear(&var); } hr = pPropBag->Write(L"FriendlyName", &var); // WaveInID applies only to audio capture devices. hr = pPropBag->Read(L"WaveInID", &var, 0); if (SUCCEEDED(hr)) { printf("%d: WaveIn ID: %d\n", counter, var.lVal); VariantClear(&var); } hr = pPropBag->Read(L"DevicePath", &var, 0); if (SUCCEEDED(hr)) { // The device path is not intended for display. printf("%d: Device path: %S\n", counter, var.bstrVal); VariantClear(&var); } pPropBag->Release(); pMoniker->Release(); counter++; } } HRESULT CWebcam::InitializeVMR( HWND hwndApp, // Application window. IGraphBuilder* pFG, // Pointer to the Filter Graph Manager. IVMRWindowlessControl** ppWc, // Receives the interface. DWORD dwNumStreams, // Number of streams to use. BOOL fBlendAppImage // Are we alpha-blending a bitmap? ) { IBaseFilter* pVmr = NULL; IVMRWindowlessControl* pWc = NULL; *ppWc = NULL; // Create the VMR and add it to the filter graph. HRESULT hr = CoCreateInstance(CLSID_VideoMixingRenderer, NULL, CLSCTX_INPROC, IID_IBaseFilter, (void**)&pVmr); if (FAILED(hr)) { return hr; } hr = pFG->AddFilter(pVmr, L"Video Mixing Renderer"); if (FAILED(hr)) { pVmr->Release(); return hr; } // Set the rendering mode and number of streams. IVMRFilterConfig* pConfig; hr = pVmr->QueryInterface(IID_IVMRFilterConfig, (void**)&pConfig); if (SUCCEEDED(hr)) { pConfig->SetRenderingMode(VMRMode_Windowless); // Set the VMR-7 to mixing mode if you want more than one video // stream, or you want to mix a static bitmap over the video. // (The VMR-9 defaults to mixing mode with four inputs.) if (dwNumStreams > 1 || fBlendAppImage) { pConfig->SetNumberOfStreams(dwNumStreams); } pConfig->Release(); hr = pVmr->QueryInterface(IID_IVMRWindowlessControl, (void**)&pWc); if (SUCCEEDED(hr)) { pWc->SetVideoClippingWindow(hwndApp); *ppWc = pWc; // The caller must release this interface. } } pVmr->Release(); // Now the VMR can be connected to other filters. return hr; }