利用directshow进行摄像头的开发

     首先，我的系统是win7的，据说win7自带directX 所以不用再另外下载directX。

在头文件中添加 #pragma comment (lib,"Strmiids")#pragma comment (lib,"quartz")#include <Dshow.h>//// 所有DirectShow应用程序必备

首先：查找视频设备列表

void CCameraDlg::GetAllCapDevices(){UINT uIndex=0;//释放视频设备列表for(int i=0;i<NUMELMS(m_rgpmVideoMenu);i++){IMonRelease(m_rgpmVideoMenu[i]);}//枚举所有的视频捕捉设备ICreateDevEnum *pCreateDevEnum=0;HRESULT hr=CoCreateInstance(CLSID_SystemDeviceEnum,NULL,CLSCTX_INPROC_SERVER,IID_ICreateDevEnum,(void**)&pCreateDevEnum);//创建所有系统设备枚举if (hr!=NOERROR){Error(TEXT("Error Creatint Device Enumerator"));return;}IEnumMoniker *pEm=0;hr=pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory,&pEm,0);//筛选出视频输入设备if (hr!=NOERROR){Error(TEXT("Sorry, you have no video capture hardware./r/n/r/n"));}pEm->Reset();ULONG cFetched;IMoniker *pM;while ((hr=pEm->Next(1,&pM,&cFetched))==S_OK)//循环直到最后一个设备为止{IPropertyBag *pBag=0;hr=pM->BindToStorage(0,0,IID_IPropertyBag,(void **)&pBag);//把对象绑定到相应的属性对象if (SUCCEEDED(hr)){VARIANT var;var.vt=VT_BSTR;hr=pBag->Read(L"FriendlyName",&var,NULL);if (hr==NOERROR){CString strDeviceName=var.bstrVal;//CString strMenuItem;//strMenuItem.Format("%d)%s",(uIndex+1),strDeviceName);SysFreeString(var.bstrVal);m_rgpmVideoMenu[uIndex]=pM;pM->AddRef();}pBag->Release();}pM->Release();uIndex++;}pEm->Release();}void CCameraDlg::IMonRelease(IMoniker *&pm){if (pm){pm->Release();pm=0;}}

 

错误函数是：

 

void CCameraDlg::Error( TCHAR *pText ){::MessageBox(NULL,pText,TEXT("Error!"),MB_OK|MB_TASKMODAL|MB_SETFOREGROUND);}

在就是进行进行视频的连接与显示：

 HRESULT CCameraDlg::InitAndStartPreview(){if (NUMELMS(m_rgpmVideoMenu)>0){HRESULT hr=m_rgpmVideoMenu[0]->BindToObject(0,0,IID_IBaseFilter,(void**)&m_pVcap);//将选择的设备绑定到源滤镜 if (!m_pVcap) {Error(TEXT("There is NO USB/Web Camera for video capture!Please check!"));return E_FAIL; }hr=m_pCaptureGraph.CoCreateInstance(CLSID_FilterGraph);if (!m_pCaptureGraph){Error( TEXT("Could not create filter graph"));return E_FAIL;}hr=m_pCaptureGraph->AddFilter(m_pVcap,L"VideoPreview");if( FAILED( hr ) ){Error( TEXT("Could not put capture device in graph"));return E_FAIL;}hr = m_pBuilder.CoCreateInstance( CLSID_CaptureGraphBuilder2 );if( !m_pBuilder ){Error( TEXT("Could not create capture graph builder2"));return hr;}hr = m_pBuilder->SetFiltergraph(m_pCaptureGraph); //if(hr != NOERROR){Error(TEXT("Cannot give graph to builder"));return E_FAIL;}//连接视频捕捉图像的Filtershr=m_pBuilder->RenderStream(&PIN_CATEGORY_PREVIEW,&MEDIATYPE_Interleaved,m_pVcap,NULL,NULL);if (FAILED(hr)){hr=m_pBuilder->RenderStream(&PIN_CATEGORY_PREVIEW,&MEDIATYPE_Video,m_pVcap,NULL,NULL);if (FAILED(hr)){hr=m_pBuilder->RenderStream(&PIN_CATEGORY_CAPTURE,&MEDIATYPE_Video,m_pVcap,NULL,NULL);}}// find the video window and stuff it in our windowCComQIPtr< IVideoWindow, &IID_IVideoWindow > pWindow = m_pCaptureGraph; //VideoWindow接口if( !pWindow ){Error( TEXT("Could not get video window interface"));return E_FAIL;}// set up the preview window to be in our dialog instead of floating popupHWND hwndPreview=NULL;GetDlgItem(IDC_PREVIEW_AVI,&hwndPreview);//获得预览窗口控件的HwndRECT rc;::GetWindowRect(hwndPreview,&rc);hr=pWindow->put_Owner((OAHWND)hwndPreview);hr=pWindow->put_Left(0);hr=pWindow->put_Top(0);hr=pWindow->put_Width(rc.right-rc.left);hr=pWindow->put_Height(rc.bottom-rc.top);hr=pWindow->put_WindowStyle(WS_CHILD|WS_CLIPSIBLINGS);hr=pWindow->put_Visible(OATRUE);// run the filter graph，IMediaControl接口提供了数据在Filer Graph中的流向CComQIPtr< IMediaControl, &IID_IMediaControl > pControl = m_pCaptureGraph;hr = pControl->Run( );if( FAILED( hr ) ){Error( TEXT("Could not run graph"));return hr;}}}

 

最好在CCameraDlg：：OnInitDialog（）函数中加入

CoInitializeEx(NULL,COINIT_APARTMENTTHREADED);//初始化COM环境ZeroMemory(m_rgpmVideoMenu, sizeof(m_rgpmVideoMenu));GetAllCapDevices();InitAndStartPreview();

这样就能够简单的显示了。