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DirectShow是微软公司提供的一套在Windows平台上进行流媒体处理的开发包,与DirectX开发包一起发布。DirectShow为多媒体流的捕捉和回放提供了强有力的支持。用DirectShow开发应用程序,我们可以很方便地从支持WDM驱动模型的采集卡上捕获数据,并且进行相应的后期处理乃至存储到文件中。 DirectShow是基于COM的,为了编写DirectShow应用程序,需要了解COM客户程序编写的基础知识。DirectShow提供了大量的接口,但在编程中发现还是不够方便,如果能构建一个视频捕捉类把常用的一些动作封装起来,那么就更方便了。 编程思路 为了更加容易建立视频捕捉应用程序,DirectShow提供了一个叫做Capture Graph Builder的对象,Capture Graph Builder提供IcaptureGraphBuilder2接口,该接口可以建立和控制Capture Graph。 建立视频捕捉程序,必须首先获取并初始化IcaptureGraphBuilder2接口,然后选择一个适当的视频捕捉设备。选择好设备后,为该设备创建Capture filter,然后调用AddFilter把Capture filter添加到Filter Graph。 如果仅仅希望用摄像头来进行实时监控的话,只需要在上面的基础上调用ICaptureGraphBuilder2::RenderStream就可以了:
ICaptureGraphBuilder2 *pBuild; // Capture Graph Builder//省略初始化部分代码IBaseFilter *pCap; // Video capture filter.//省略初始化和添加到Filter Graph部分代码pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, pCap, NULL, NULL); DirectShow提供了一个捕捉静态图像的方法:使用Sample Grabber filter。依次按照以下三个步骤就可以了: 第一步, 定义一个类实现Sample Grabber的回调接口IsampleGrabberCB:
class CSampleGrabberCB : public ISampleGrabberCB{ //在后面提供的类中具体完成}CSampleGrabberCB mCB; 第二步、调用RenderStream依次把Still pin、Sample Grabber和系统默认Renderer Filter连接起来。 第三步、配置Sample Grabber以捕获数据。 视频捕捉类CCaptureVideo的具体实现
// CCaptureVideo视频捕捉类头文件/////////////////////////////////////////////////////////////////////#if !defined(AFX_CAPTUREVIDEO_H__F5345AA4_A39F_4B07_B843_3D87C4287AA0__INCLUDED_)#define AFX_CAPTUREVIDEO_H__F5345AA4_A39F_4B07_B843_3D87C4287AA0__INCLUDED_/////////////////////////////////////////////////////////////////////// CaptureVideo.h : header file/////////////////////////////////////////////////////////////////////#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000#include
#include #include #ifndef SAFE_RELEASE#define SAFE_RELEASE( x ) \if ( NULL != x ) \{ \ x->Release( ); \ x = NULL; \}#endifclass CSampleGrabberCB;class CCaptureVideo : public CWnd { friend class CSampleGrabberCB; public: void GrabOneFrame(BOOL bGrab); HRESULT Init(int iDeviceID,HWND hWnd); int EnumDevices(HWND hList); CCaptureVideo(); virtual ~CCaptureVideo(); private: HWND m_hWnd; IGraphBuilder *m_pGB; ICaptureGraphBuilder2* m_pCapture; IBaseFilter* m_pBF; IMediaControl* m_pMC; IVideoWindow* m_pVW; CComPtr m_pGrabber; protected: void FreeMediaType(AM_MEDIA_TYPE& mt); bool BindFilter(int deviceId, IBaseFilter **pFilter); void ResizeVideoWindow(); HRESULT SetupVideoWindow(); HRESULT InitCaptureGraphBuilder();};#endif // !defined(AFX_CAPTUREVIDEO_H__F5345AA4_A39F_4B07_B843_3D87C4287AA0__INCLUDED_)//-------------------------------------------------------------------// CCaptureVideo视频捕捉类实现文件CaptureVideo.cpp//-------------------------------------------------------------------// CaptureVideo.cpp: implementation of the CCaptureVideo class.///////////////////////////////////////////////////////////////////////#include "stdafx.h"#include "CaptureVideo.h"#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE[]=__FILE__;#define new DEBUG_NEW#endifBOOL bOneShot=FALSE;//全局变量class CSampleGrabberCB : public ISampleGrabberCB { public: long lWidth; long lHeight; TCHAR m_szFileName[MAX_PATH];// 位图文件名称 CSampleGrabberCB( ){ strcpy(m_szFileName, "c:\\donaldo.bmp"); } STDMETHODIMP_(ULONG) AddRef() { return 2; } STDMETHODIMP_(ULONG) Release() { return 1; } STDMETHODIMP QueryInterface(REFIID riid, void ** ppv){ if( riid == IID_ISampleGrabberCB || riid == IID_IUnknown ){ *ppv = (void *) static_cast ( this ); return NOERROR; } return E_NOINTERFACE; } STDMETHODIMP SampleCB( double SampleTime, IMediaSample * pSample ){ return 0;}STDMETHODIMP BufferCB( double dblSampleTime, BYTE * pBuffer, long lBufferSize ){ if( !bOneShot )return 0; if (!pBuffer)return E_POINTER; SaveBitmap(pBuffer, lBufferSize); bOneShot = FALSE; return 0;}//创建位图文件BOOL SaveBitmap(BYTE * pBuffer, long lBufferSize ){ HANDLE hf = CreateFile( m_szFileName, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, NULL, NULL ); if( hf == INVALID_HANDLE_VALUE )return 0; // 写文件头 BITMAPFILEHEADER bfh; memset( &bfh, 0, sizeof( bfh ) ); bfh.bfType = ’MB’; bfh.bfSize = sizeof( bfh ) lBufferSize sizeof( BITMAPINFOHEADER ); bfh.bfOffBits = sizeof( BITMAPINFOHEADER ) sizeof( BITMAPFILEHEADER ); DWORD dwWritten = 0; WriteFile( hf, &bfh, sizeof( bfh ), &dwWritten, NULL ); // 写位图格式 BITMAPINFOHEADER bih; memset( &bih, 0, sizeof( bih ) ); bih.biSize = sizeof( bih ); bih.biWidth = lWidth; bih.biHeight = lHeight; bih.biPlanes = 1; bih.biBitCount = 24; WriteFile( hf, &bih, sizeof( bih ), &dwWritten, NULL ); // 写位图数据 WriteFile( hf, pBuffer, lBufferSize, &dwWritten, NULL ); CloseHandle( hf ); return 0; }};CSampleGrabberCB mCB;//////////////////////////////////////////////////////////////////////// Construction/Destruction//////////////////////////////////////////////////////////////////////CCaptureVideo::CCaptureVideo(){ //COM Library Intialization if(FAILED(CoInitialize(NULL))) /*, COINIT_APARTMENTTHREADED)))*/ { AfxMessageBox("CoInitialize Failed!\r\n"); return; } m_hWnd = NULL; m_pVW = NULL; m_pMC = NULL; m_pGB = NULL; m_pCapture = NULL; }CCaptureVideo::~CCaptureVideo(){ // Stop media playback if(m_pMC)m_pMC->Stop(); if(m_pVW){ m_pVW->put_Visible(OAFALSE); m_pVW->put_Owner(NULL); } SAFE_RELEASE(m_pCapture); SAFE_RELEASE(m_pMC); SAFE_RELEASE(m_pGB); SAFE_RELEASE(m_pBF); CoUninitialize( );}int CCaptureVideo::EnumDevices(HWND hList){ if (!hList) return -1; int id = 0; //枚举视频扑捉设备 ICreateDevEnum *pCreateDevEnum; HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,IID_ICreateDevEnum, (void**)&pCreateDevEnum); if (hr != NOERROR)return -1; CComPtr pEm; hr = pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory,&pEm, 0); if (hr != NOERROR)return -1; pEm->Reset(); ULONG cFetched; IMoniker *pM; while(hr = pEm->Next(1, &pM, &cFetched), hr==S_OK) { IPropertyBag *pBag; hr = pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag); if(SUCCEEDED(hr)) { VARIANT var; var.vt = VT_BSTR; hr = pBag->Read(L"FriendlyName", &var, NULL); if (hr == NOERROR) { TCHAR str[2048]; id ; WideCharToMultiByte(CP_ACP,0,var.bstrVal, -1, str, 2048, NULL, NULL); ::SendMessage(hList, CB_ADDSTRING, 0,(LPARAM)str); SysFreeString(var.bstrVal); } pBag->Release(); } pM->Release(); } return id;}HRESULT CCaptureVideo::Init(int iDeviceID, HWND hWnd){ HRESULT hr; hr = InitCaptureGraphBuilder(); if (FAILED(hr)){ AfxMessageBox("Failed to get video interfaces!"); return hr; } // Bind Device Filter. We know the device because the id was passed in if(!BindFilter(iDeviceID, &m_pBF))return S_FALSE; hr = m_pGB->AddFilter(m_pBF, L"Capture Filter"); // hr = m_pCapture->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, // m_pBF, NULL, NULL); // create a sample grabber hr = m_pGrabber.CoCreateInstance( CLSID_SampleGrabber ); if( !m_pGrabber ){ AfxMessageBox("Fail to create SampleGrabber, maybe qedit.dll is not registered?"); return hr; } CComQIPtr< IBaseFilter, &IID_IBaseFilter > pGrabBase( m_pGrabber ); //设置视频格式 AM_MEDIA_TYPE mt; ZeroMemory(&mt, sizeof(AM_MEDIA_TYPE)); mt.majortype = MEDIATYPE_Video; mt.subtype = MEDIASUBTYPE_RGB24; hr = m_pGrabber->SetMediaType(&mt); if( FAILED( hr ) ){ AfxMessageBox("Fail to set media type!"); return hr; } hr = m_pGB->AddFilter( pGrabBase, L"Grabber" ); if( FAILED( hr ) ){ AfxMessageBox("Fail to put sample grabber in graph"); return hr; } // try to render preview/capture pin hr = m_pCapture->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video,m_pBF,pGrabBase,NULL); if( FAILED( hr ) ) hr = m_pCapture->RenderStream(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Video,m_pBF,pGrabBase,NULL); if( FAILED( hr ) ){ AfxMessageBox("Can’t build the graph"); return hr; } hr = m_pGrabber->GetConnectedMediaType( &mt ); if ( FAILED( hr) ){ AfxMessageBox("Failt to read the connected media type"); return hr; } VIDEOINFOHEADER * vih = (VIDEOINFOHEADER*) mt.pbFormat; mCB.lWidth = vih->bmiHeader.biWidth; mCB.lHeight = vih->bmiHeader.biHeight; FreeMediaType(mt); hr = m_pGrabber->SetBufferSamples( FALSE ); hr = m_pGrabber->SetOneShot( FALSE ); hr = m_pGrabber->SetCallback( &mCB, 1 ); //设置视频捕捉窗口 m_hWnd = hWnd ; SetupVideoWindow(); hr = m_pMC->Run();//开始视频捕捉 if(FAILED(hr)){AfxMessageBox("Couldn’t run the graph!");return hr;} return S_OK;}bool CCaptureVideo::BindFilter(int deviceId, IBaseFilter **pFilter){ if (deviceId < 0) return false; // enumerate all video capture devices CComPtr pCreateDevEnum; HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,IID_ICreateDevEnum, (void**)&pCreateDevEnum); if (hr != NOERROR) { return false; } CComPtr pEm; hr = pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory,&pEm, 0); if (hr != NOERROR) { return false; } pEm->Reset(); ULONG cFetched; IMoniker *pM; int index = 0; while(hr = pEm->Next(1, &pM, &cFetched), hr==S_OK, index <= deviceId) { IPropertyBag *pBag; hr = pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag); if(SUCCEEDED(hr)) { VARIANT var; var.vt = VT_BSTR; hr = pBag->Read(L"FriendlyName", &var, NULL); if (hr == NOERROR) { if (index == deviceId) { pM->BindToObject(0, 0, IID_IBaseFilter, (void**)pFilter); } SysFreeString(var.bstrVal); } pBag->Release(); } pM->Release(); index ; } return true;}HRESULT CCaptureVideo::InitCaptureGraphBuilder(){ HRESULT hr; // 创建IGraphBuilder接口 hr=CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void **)&m_pGB); // 创建ICaptureGraphBuilder2接口 hr = CoCreateInstance (CLSID_CaptureGraphBuilder2 , NULL, CLSCTX_INPROC,IID_ICaptureGraphBuilder2, (void **) &m_pCapture); if (FAILED(hr))return hr; m_pCapture->SetFiltergraph(m_pGB); hr = m_pGB->QueryInterface(IID_IMediaControl, (void **)&m_pMC); if (FAILED(hr))return hr; hr = m_pGB->QueryInterface(IID_IVideoWindow, (LPVOID *) &m_pVW); if (FAILED(hr))return hr; return hr;}HRESULT CCaptureVideo::SetupVideoWindow(){ HRESULT hr; hr = m_pVW->put_Owner((OAHWND)m_hWnd); if (FAILED(hr))return hr; hr = m_pVW->put_WindowStyle(WS_CHILD | WS_CLIPCHILDREN); if (FAILED(hr))return hr; ResizeVideoWindow(); hr = m_pVW->put_Visible(OATRUE); return hr;}void CCaptureVideo::ResizeVideoWindow(){ if (m_pVW){ //让图像充满整个窗口 CRect rc; ::GetClientRect(m_hWnd,&rc); m_pVW->SetWindowPosition(0, 0, rc.right, rc.bottom); } }void CCaptureVideo::GrabOneFrame(BOOL bGrab){ bOneShot = bGrab;}void CCaptureVideo::FreeMediaType(AM_MEDIA_TYPE& mt){ if (mt.cbFormat != 0) { CoTaskMemFree((PVOID)mt.pbFormat); // Strictly unnecessary but tidier mt.cbFormat = 0; mt.pbFormat = NULL; } if (mt.pUnk != NULL) { mt.pUnk->Release(); mt.pUnk = NULL; }}共2页。 1 2 :
DirectShow是微软公司提供的一套在Windows平台上进行流媒体处理的开发包,与DirectX开发包一起发布。DirectShow为多媒体流的捕捉和回放提供了强有力的支持。用DirectShow开发应用程序,我们可以很方便地从支持WDM驱动模型的采集卡上捕获数据,并且进行相应的后期处理乃至存储到文件中。 DirectShow是基于COM的,为了编写DirectShow应用程序,需要了解COM客户程序编写的基础知识。DirectShow提供了大量的接口,但在编程中发现还是不够方便,如果能构建一个视频捕捉类把常用的一些动作封装起来,那么就更方便了。 编程思路 为了更加容易建立视频捕捉应用程序,DirectShow提供了一个叫做Capture Graph Builder的对象,Capture Graph Builder提供IcaptureGraphBuilder2接口,该接口可以建立和控制Capture Graph。 建立视频捕捉程序,必须首先获取并初始化IcaptureGraphBuilder2接口,然后选择一个适当的视频捕捉设备。选择好设备后,为该设备创建Capture filter,然后调用AddFilter把Capture filter添加到Filter Graph。 如果仅仅希望用摄像头来进行实时监控的话,只需要在上面的基础上调用ICaptureGraphBuilder2::RenderStream就可以了:
ICaptureGraphBuilder2 *pBuild; // Capture Graph Builder//省略初始化部分代码IBaseFilter *pCap; // Video capture filter.//省略初始化和添加到Filter Graph部分代码pBuild->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, pCap, NULL, NULL); DirectShow提供了一个捕捉静态图像的方法:使用Sample Grabber filter。依次按照以下三个步骤就可以了: 第一步, 定义一个类实现Sample Grabber的回调接口IsampleGrabberCB:
class CSampleGrabberCB : public ISampleGrabberCB{ //在后面提供的类中具体完成}CSampleGrabberCB mCB; 第二步、调用RenderStream依次把Still pin、Sample Grabber和系统默认Renderer Filter连接起来。 第三步、配置Sample Grabber以捕获数据。 视频捕捉类CCaptureVideo的具体实现
// CCaptureVideo视频捕捉类头文件/////////////////////////////////////////////////////////////////////#if !defined(AFX_CAPTUREVIDEO_H__F5345AA4_A39F_4B07_B843_3D87C4287AA0__INCLUDED_)#define AFX_CAPTUREVIDEO_H__F5345AA4_A39F_4B07_B843_3D87C4287AA0__INCLUDED_/////////////////////////////////////////////////////////////////////// CaptureVideo.h : header file/////////////////////////////////////////////////////////////////////#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000#include #include #include #ifndef SAFE_RELEASE#define SAFE_RELEASE( x ) \if ( NULL != x ) \{ \ x->Release( ); \ x = NULL; \}#endifclass CSampleGrabberCB;class CCaptureVideo : public CWnd { friend class CSampleGrabberCB; public: void GrabOneFrame(BOOL bGrab); HRESULT Init(int iDeviceID,HWND hWnd); int EnumDevices(HWND hList); CCaptureVideo(); virtual ~CCaptureVideo(); private: HWND m_hWnd; IGraphBuilder *m_pGB; ICaptureGraphBuilder2* m_pCapture; IBaseFilter* m_pBF; IMediaControl* m_pMC; IVideoWindow* m_pVW; CComPtr m_pGrabber; protected: void FreeMediaType(AM_MEDIA_TYPE& mt); bool BindFilter(int deviceId, IBaseFilter **pFilter); void ResizeVideoWindow(); HRESULT SetupVideoWindow(); HRESULT InitCaptureGraphBuilder();};#endif // !defined(AFX_CAPTUREVIDEO_H__F5345AA4_A39F_4B07_B843_3D87C4287AA0__INCLUDED_)//-------------------------------------------------------------------// CCaptureVideo视频捕捉类实现文件CaptureVideo.cpp//-------------------------------------------------------------------// CaptureVideo.cpp: implementation of the CCaptureVideo class.///////////////////////////////////////////////////////////////////////#include "stdafx.h"#include "CaptureVideo.h"#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE[]=__FILE__;#define new DEBUG_NEW#endifBOOL bOneShot=FALSE;//全局变量class CSampleGrabberCB : public ISampleGrabberCB { public: long lWidth; long lHeight; TCHAR m_szFileName[MAX_PATH];// 位图文件名称 CSampleGrabberCB( ){ strcpy(m_szFileName, "c:\\donaldo.bmp"); } STDMETHODIMP_(ULONG) AddRef() { return 2; } STDMETHODIMP_(ULONG) Release() { return 1; } STDMETHODIMP QueryInterface(REFIID riid, void ** ppv){ if( riid == IID_ISampleGrabberCB || riid == IID_IUnknown ){ *ppv = (void *) static_cast ( this ); return NOERROR; } return E_NOINTERFACE; } STDMETHODIMP SampleCB( double SampleTime, IMediaSample * pSample ){ return 0;}STDMETHODIMP BufferCB( double dblSampleTime, BYTE * pBuffer, long lBufferSize ){ if( !bOneShot )return 0; if (!pBuffer)return E_POINTER; SaveBitmap(pBuffer, lBufferSize); bOneShot = FALSE; return 0;}//创建位图文件BOOL SaveBitmap(BYTE * pBuffer, long lBufferSize ){ HANDLE hf = CreateFile( m_szFileName, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, NULL, NULL ); if( hf == INVALID_HANDLE_VALUE )return 0; // 写文件头 BITMAPFILEHEADER bfh; memset( &bfh, 0, sizeof( bfh ) ); bfh.bfType = ’MB’; bfh.bfSize = sizeof( bfh ) lBufferSize sizeof( BITMAPINFOHEADER ); bfh.bfOffBits = sizeof( BITMAPINFOHEADER ) sizeof( BITMAPFILEHEADER ); DWORD dwWritten = 0; WriteFile( hf, &bfh, sizeof( bfh ), &dwWritten, NULL ); // 写位图格式 BITMAPINFOHEADER bih; memset( &bih, 0, sizeof( bih ) ); bih.biSize = sizeof( bih ); bih.biWidth = lWidth; bih.biHeight = lHeight; bih.biPlanes = 1; bih.biBitCount = 24; WriteFile( hf, &bih, sizeof( bih ), &dwWritten, NULL ); // 写位图数据 WriteFile( hf, pBuffer, lBufferSize, &dwWritten, NULL ); CloseHandle( hf ); return 0; }};CSampleGrabberCB mCB;//////////////////////////////////////////////////////////////////////// Construction/Destruction//////////////////////////////////////////////////////////////////////CCaptureVideo::CCaptureVideo(){ //COM Library Intialization if(FAILED(CoInitialize(NULL))) /*, COINIT_APARTMENTTHREADED)))*/ { AfxMessageBox("CoInitialize Failed!\r\n"); return; } m_hWnd = NULL; m_pVW = NULL; m_pMC = NULL; m_pGB = NULL; m_pCapture = NULL; }CCaptureVideo::~CCaptureVideo(){ // Stop media playback if(m_pMC)m_pMC->Stop(); if(m_pVW){ m_pVW->put_Visible(OAFALSE); m_pVW->put_Owner(NULL); } SAFE_RELEASE(m_pCapture); SAFE_RELEASE(m_pMC); SAFE_RELEASE(m_pGB); SAFE_RELEASE(m_pBF); CoUninitialize( );}int CCaptureVideo::EnumDevices(HWND hList){ if (!hList) return -1; int id = 0; //枚举视频扑捉设备 ICreateDevEnum *pCreateDevEnum; HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,IID_ICreateDevEnum, (void**)&pCreateDevEnum); if (hr != NOERROR)return -1; CComPtr pEm; hr = pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory,&pEm, 0); if (hr != NOERROR)return -1; pEm->Reset(); ULONG cFetched; IMoniker *pM; while(hr = pEm->Next(1, &pM, &cFetched), hr==S_OK) { IPropertyBag *pBag; hr = pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag); if(SUCCEEDED(hr)) { VARIANT var; var.vt = VT_BSTR; hr = pBag->Read(L"FriendlyName", &var, NULL); if (hr == NOERROR) { TCHAR str[2048]; id ; WideCharToMultiByte(CP_ACP,0,var.bstrVal, -1, str, 2048, NULL, NULL); ::SendMessage(hList, CB_ADDSTRING, 0,(LPARAM)str); SysFreeString(var.bstrVal); } pBag->Release(); } pM->Release(); } return id;}HRESULT CCaptureVideo::Init(int iDeviceID, HWND hWnd){ HRESULT hr; hr = InitCaptureGraphBuilder(); if (FAILED(hr)){ AfxMessageBox("Failed to get video interfaces!"); return hr; } // Bind Device Filter. We know the device because the id was passed in if(!BindFilter(iDeviceID, &m_pBF))return S_FALSE; hr = m_pGB->AddFilter(m_pBF, L"Capture Filter"); // hr = m_pCapture->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, // m_pBF, NULL, NULL); // create a sample grabber hr = m_pGrabber.CoCreateInstance( CLSID_SampleGrabber ); if( !m_pGrabber ){ AfxMessageBox("Fail to create SampleGrabber, maybe qedit.dll is not registered?"); return hr; } CComQIPtr< IBaseFilter, &IID_IBaseFilter > pGrabBase( m_pGrabber ); //设置视频格式 AM_MEDIA_TYPE mt; ZeroMemory(&mt, sizeof(AM_MEDIA_TYPE)); mt.majortype = MEDIATYPE_Video; mt.subtype = MEDIASUBTYPE_RGB24; hr = m_pGrabber->SetMediaType(&mt); if( FAILED( hr ) ){ AfxMessageBox("Fail to set media type!"); return hr; } hr = m_pGB->AddFilter( pGrabBase, L"Grabber" ); if( FAILED( hr ) ){ AfxMessageBox("Fail to put sample grabber in graph"); return hr; } // try to render preview/capture pin hr = m_pCapture->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video,m_pBF,pGrabBase,NULL); if( FAILED( hr ) ) hr = m_pCapture->RenderStream(&PIN_CATEGORY_CAPTURE, &MEDIATYPE_Video,m_pBF,pGrabBase,NULL); if( FAILED( hr ) ){ AfxMessageBox("Can’t build the graph"); return hr; } hr = m_pGrabber->GetConnectedMediaType( &mt ); if ( FAILED( hr) ){ AfxMessageBox("Failt to read the connected media type"); return hr; } VIDEOINFOHEADER * vih = (VIDEOINFOHEADER*) mt.pbFormat; mCB.lWidth = vih->bmiHeader.biWidth; mCB.lHeight = vih->bmiHeader.biHeight; FreeMediaType(mt); hr = m_pGrabber->SetBufferSamples( FALSE ); hr = m_pGrabber->SetOneShot( FALSE ); hr = m_pGrabber->SetCallback( &mCB, 1 ); //设置视频捕捉窗口 m_hWnd = hWnd ; SetupVideoWindow(); hr = m_pMC->Run();//开始视频捕捉 if(FAILED(hr)){AfxMessageBox("Couldn’t run the graph!");return hr;} return S_OK;}bool CCaptureVideo::BindFilter(int deviceId, IBaseFilter **pFilter){ if (deviceId < 0) return false; // enumerate all video capture devices CComPtr pCreateDevEnum; HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,IID_ICreateDevEnum, (void**)&pCreateDevEnum); if (hr != NOERROR) { return false; } CComPtr pEm; hr = pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory,&pEm, 0); if (hr != NOERROR) { return false; } pEm->Reset(); ULONG cFetched; IMoniker *pM; int index = 0; while(hr = pEm->Next(1, &pM, &cFetched), hr==S_OK, index <= deviceId) { IPropertyBag *pBag; hr = pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag); if(SUCCEEDED(hr)) { VARIANT var; var.vt = VT_BSTR; hr = pBag->Read(L"FriendlyName", &var, NULL); if (hr == NOERROR) { if (index == deviceId) { pM->BindToObject(0, 0, IID_IBaseFilter, (void**)pFilter); } SysFreeString(var.bstrVal); } pBag->Release(); } pM->Release(); index ; } return true;}HRESULT CCaptureVideo::InitCaptureGraphBuilder(){ HRESULT hr; // 创建IGraphBuilder接口 hr=CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void **)&m_pGB); // 创建ICaptureGraphBuilder2接口 hr = CoCreateInstance (CLSID_CaptureGraphBuilder2 , NULL, CLSCTX_INPROC,IID_ICaptureGraphBuilder2, (void **) &m_pCapture); if (FAILED(hr))return hr; m_pCapture->SetFiltergraph(m_pGB); hr = m_pGB->QueryInterface(IID_IMediaControl, (void **)&m_pMC); if (FAILED(hr))return hr; hr = m_pGB->QueryInterface(IID_IVideoWindow, (LPVOID *) &m_pVW); if (FAILED(hr))return hr; return hr;}HRESULT CCaptureVideo::SetupVideoWindow(){ HRESULT hr; hr = m_pVW->put_Owner((OAHWND)m_hWnd); if (FAILED(hr))return hr; hr = m_pVW->put_WindowStyle(WS_CHILD | WS_CLIPCHILDREN); if (FAILED(hr))return hr; ResizeVideoWindow(); hr = m_pVW->put_Visible(OATRUE); return hr;}void CCaptureVideo::ResizeVideoWindow(){ if (m_pVW){ //让图像充满整个窗口 CRect rc; ::GetClientRect(m_hWnd,&rc); m_pVW->SetWindowPosition(0, 0, rc.right, rc.bottom); } }void CCaptureVideo::GrabOneFrame(BOOL bGrab){ bOneShot = bGrab;}void CCaptureVideo::FreeMediaType(AM_MEDIA_TYPE& mt){ if (mt.cbFormat != 0) { CoTaskMemFree((PVOID)mt.pbFormat); // Strictly unnecessary but tidier mt.cbFormat = 0; mt.pbFormat = NULL; } if (mt.pUnk != NULL) { mt.pUnk->Release(); mt.pUnk = NULL; }}共2页。 1 2 :
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