directshow摄像头抓图有bug_错误提示截图

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最近在ＶＣ６．０平台下写一个用directshow做一个从免驱动UBS摄像头上抓取图片的程序，预览视频没问题，但抓取图像时老出现内存不能读的问题，抓取图像的代码如下，BOOL CCaptureCla::CaptureBitmap(const char * outFile)//const char * outFile){

HRESULT hr=0;AM_MEDIA_TYPE mt;hr = pGrabber->GetConnectedMediaType(&mt);

if(FAILED(hr)){ AfxMeageBox(“Failt to read the connected media type”);return FALSE;

}// Examine the format block.VIDEOINFOHEADER *pVih;

if((mt.formattype == FORMAT_VideoInfo)&&(mt.cbFormat >= sizeof(VIDEOINFOHEADER))&&(mt.pbFormat!= NULL))

{

pVih =(VIDEOINFOHEADER*)mt.pbFormat;}else

{

// Wrong format.Free the format block and return an error.return VFW_E_INVALIDMEDIATYPE;}// Set one-shot mode and buffering.hr = pGrabber->SetOneShot(TRUE);

if(SUCCEEDED(pGrabber->SetBufferSamples(TRUE))){

bool pa = false;

m_pMC->Run();long EvCode;AfxMeageBox(“18”);

hr = pEvent->WaitForCompletion(INFINITE,&EvCode);

AfxMeageBox(“6”);//find the required buffer size

long cbBuffer = 0;if(SUCCEEDED(pGrabber->GetCurrentBuffer(&cbBuffer, NULL)))

{//Allocate the array and call the method a second time to copy the buffer:

char *pBuffer = new char[cbBuffer];

if(!pBuffer)

{ // Out of memory.Return an error code.AfxMeageBox(_T(“Out of Memory”));

}

hr = pGrabber->GetCurrentBuffer(&cbBuffer,(long*)(pBuffer));

//写到BMP文件中

HANDLE hf = CreateFile(LPCTSTR(outFile), GENERIC_WRITE, FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, 0, NULL);

if(hf == INVALID_HANDLE_VALUE)

{ return 0;

}

// Write the file header.BITMAPFILEHEADER bfh;

ZeroMemory(&bfh, sizeof(bfh));

bfh.bfType = 'MB';// Little-endian for “MB”.bfh.bfSize = sizeof(bfh)+ cbBuffer + sizeof(BITMAPINFOHEADER);

bfh.bfOffBits = sizeof(BITMAPFILEHEADER)+ sizeof(BITMAPINFOHEADER);

DWORD dwWritten = 0;

WriteFile(hf, &bfh, sizeof(bfh), &dwWritten, NULL);

// Write the bitmap format

BITMAPINFOHEADER bih;

ZeroMemory(&bih, sizeof(bih));

bih.biSize = sizeof(bih);bih.biWidth = pVih->bmiHeader.biWidth;

bih.biHeight = pVih->bmiHeader.biHeight;

bih.biPlanes = pVih->bmiHeader.biPlanes;

bih.biBitCount = pVih->bmiHeader.biBitCount;

dwWritten = 0;

WriteFile(hf, &bih, sizeof(bih), &dwWritten, NULL);

//write the bitmap bits

dwWritten = 0;

WriteFile(hf, pBuffer, cbBuffer, &dwWritten, NULL);

CloseHandle(hf);

pa = true;

}

return pa;

}

hr = pGrabber->SetOneShot(FALSE);

return true;

}

问题补充：编译可以通过，就是运行时出现内存不能读的问题，经调试发现执行hr = pEvent->WaitForCompletion(INFINITE,&EvCode);这行代码是出现没存不能读的问题。各位大牛大虾们指点下，急用哦！