学步园

     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")<br /> #pragma comment (lib,"quartz")<br /> #include <Dshow.h>//// 所有DirectShow应用程序必备<br />

首先：查找视频设备列表

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

错误函数是：

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

在就是进行进行视频的连接与显示：

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

最好在CCameraDlg：：OnInitDialog（）函数中加入

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

这样就能够简单的显示了。