用DirectShow开发视频监控、动态捕捉程序

可以实现视频的时实显示，也可以交互式的抓取一帧图像，保存为位图文件。

主要类的源代码如下：

 // CaptureVideo.cpp : implementation file
//

#include "stdafx.h"
#include "CameraShowAndTest.h"
#include "CaptureVideo.h"
#include <streams.h>

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

BOOL bOneShot=FALSE; //全局变量
class CSampleGrabberCB : public ISampleGrabberCB
{
public:
 BOOLEAN GetBuffer(BYTE * pBufferIn,long lBufferSize);
 long lWidth;
 long lHeight;
 BYTE * m_pPictureBuffer;
 TCHAR m_szFileName[MAX_PATH]; // 位图文件名称
 CSampleGrabberCB()
 {
  m_szFileName[0] = '/0' ;
  m_pPictureBuffer = NULL;
 }
 ~CSampleGrabberCB()
 {
  delete m_pPictureBuffer;
  m_pPictureBuffer = NULL;
 }
 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<ISampleGrabberCB*> ( 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);
  GetBuffer(pBuffer,lBufferSize);
  bOneShot = FALSE;
  return 0;
 }
//创建位图文件
 BOOL SaveBitmap(BYTE * pBuffer, long lBufferSize )
 {
  char szFilter[] = "BMP Files(*.bmp)|*.bmp||";
  CFileDialog dlg(FALSE,NULL,NULL,OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,szFilter);
  if(dlg.DoModal() == IDOK)
  {
   strcpy(m_szFileName,dlg.GetPathName().GetBuffer(0));
   if(strstr(m_szFileName,".bmp") == NULL)
    strcat(m_szFileName,".bmp");
  }
  else
   return false;
  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;
/////////////////////////////////////////////////////////////////////////////
// CCaptureVideo

CCaptureVideo::CCaptureVideo()
{
 if(FAILED(CoInitialize(NULL))) /*, COINIT_APARTMENTTHREADED)))*/
 {
  AfxMessageBox("CoInitialize Failed!/r/n");
  return;
 }
 m_hWnd = NULL;
 m_pVW = NULL;
 m_pMC = NULL;
 m_pME = NULL;
 m_pGB = NULL;
 m_pCapture = NULL;
 m_pBF = NULL;
 m_pGrabber = NULL;
 m_bIsActived = false;
}

CCaptureVideo::~CCaptureVideo()
{
 if(m_pMC)
  m_pMC->Stop();
 if(m_pVW)
 {
  m_pVW->put_Visible(OAFALSE);
  m_pVW->put_Owner(NULL);
  m_pVW = NULL;
 }
 m_hWnd = NULL;
 m_pME = NULL;
 m_pGrabber = NULL;
 SAFE_RELEASE(m_pCapture);
 SAFE_RELEASE(m_pMC);
 SAFE_RELEASE(m_pGB);
 SAFE_RELEASE(m_pBF);
 CoUninitialize();
 m_bIsActived = false;
}
int CCaptureVideo::EnumDevices(CMenu* hmenu)
{
 int Cur_Menu_Item = ID_MENU_SYSCAMERA_BASE;  //添加动态菜单的初始ID
 if(!hmenu)
  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<IEnumMoniker> 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];
    WideCharToMultiByte(CP_ACP,0,var.bstrVal, -1, str, 2048, NULL, NULL);
    id++;
    //::SendMessage(hList, CB_ADDSTRING, 0,(LPARAM)str);
    hmenu->AppendMenu(MF_STRING,Cur_Menu_Item++,str); //Add to the menu item
    SysFreeString(var.bstrVal);    
   }
   pBag->Release();
  }
  pM->Release();
 }
 hmenu->AppendMenu(MF_SEPARATOR);
 return id;
}

HRESULT CCaptureVideo::Init(int iDeviceID, HWND hWnd)
{
 m_bIsActived = true; //判断是否已创建CCaptureVideo对象
 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");
 // 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; //OR RGB32,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<ICreateDevEnum> pCreateDevEnum;
 HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,IID_ICreateDevEnum, (void**)&pCreateDevEnum);
 if (hr != NOERROR)
 {
  return false;
 }
 CComPtr<IEnumMoniker> 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_IMediaEvent, (void **)&m_pME);
 if (FAILED(hr))
  return hr;
 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;
// hr = m_pGB->QueryInterface(IID_IMediaEventEx, (LPVOID *) &m_pMI);
// 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;
 }
}

BEGIN_MESSAGE_MAP(CCaptureVideo, CWnd)
 //{{AFX_MSG_MAP(CCaptureVideo)
 //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CCaptureVideo message handlers

bool CCaptureVideo::VideoPause()
{
 OAFilterState st;
 m_pMC->Pause();
 m_pMC->GetState(INFINITE,&st);
 if(st == State_Paused)
  return true;
 return false;
}

bool CCaptureVideo::VideoStop()
{
 
 if(m_pMC->Stop() == S_OK)
  return true;
 return false;
}

bool CCaptureVideo::VideoRun()
{
 m_pMC->Run();
 return true;
}

void CCaptureVideo::FreeAllResources()
{
 if(m_pMC)
  m_pMC->Stop();
 if(m_pVW)
 {
  m_pVW->put_Visible(OAFALSE);
  m_pVW->put_Owner(NULL);
  m_pVW = NULL;
 }
 m_hWnd = NULL;
 m_pGrabber = NULL;
 SAFE_RELEASE(m_pCapture);
 SAFE_RELEASE(m_pMC);
 SAFE_RELEASE(m_pGB);
 SAFE_RELEASE(m_pBF);
 CoUninitialize();
 m_bIsActived = false;
}

bool CCaptureVideo::IsActived()
{
 return m_bIsActived;
}
void CCaptureVideo::GetCameraPixels(long &width,long &height)
{
 width = mCB.lWidth ;
 height = mCB.lHeight ;
}

BOOLEAN CSampleGrabberCB::GetBuffer(BYTE *pBufferIn, long lBufferSize)
{
 if(m_pPictureBuffer)
  delete m_pPictureBuffer;
 m_pPictureBuffer = new BYTE[lBufferSize];
 if(!m_pPictureBuffer)
  return FALSE;
 memcpy(m_pPictureBuffer,pBufferIn,lBufferSize);
 return TRUE;
}

BYTE * CCaptureVideo::GetPictureBuffer()
{
 return mCB.m_pPictureBuffer;  //返回数组的指针
}