Video for Windows with Borland C++ Builder

Obtaining USB camera snapshots using Video for Windows with Borland C++ Builder 5. It's just a very simple code. (I tested it with a Logitech QCam Messenger.)

1. Initialization is needed as usual.
2. Then execute capGrabFrameNoStop(hWndC).
3. A snapshot is given to your callback function.

A source code (fragment) below is displaying captured bitmap with DIBSection API. Still very simple. Use freely:)

char *lpData = 0;
int DataSize = 0;

LRESULT CALLBACK capVideoStreamCallback(

  HWND hWnd,

  LPVIDEOHDR lpVHdr

) {

	CopyMemory(lpData,lpVHdr->lpData,lpVHdr->dwBufferLength);

	return true;

}

__fastcall TQCam::TQCam(TComponent* Owner)

	: TForm(Owner)

{

	Width = 700;

	Height = 550;

	hWndC = capCreateCaptureWindow ( "My Own Capture Window",

		WS_CHILD , 0, 0,320,160, Handle, 0xffff);

	capDriverConnect(hWndC,0);

	capPreview(hWndC,false);

	WORD vfs = capGetVideoFormatSize(hWndC);

	BITMAPINFOHEADER bmih;

	bmih.biSize = sizeof(BITMAPINFOHEADER);

	capGetVideoFormat(hWndC,&bmih,vfs);

	PaintBox1->Width = bmih.biWidth;

	PaintBox1->Height = bmih.biHeight;

	hDIBSec = CreateDIBSection(0,(BITMAPINFO *) &bmih, DIB_RGB_COLORS,(void **)&lpData, NULL, 0);

	capSetCallbackOnFrame(hWndC,capVideoStreamCallback);

}

__fastcall TQCam::~TQCam() {

	capCaptureStop(hWndC);

	capDriverDisconnect(hWndC);

}

void __fastcall TQCam::PaintBox1Paint(TObject *Sender)

{

	TPaintBox *pb = (TPaintBox *) Sender;

	HDC hdc = CreateCompatibleDC(0);

	SelectObject(hdc,hDIBSec);

	BitBlt(Canvas->Handle,0,0,pb->Width,pb->Height,

			hdc,0,0,SRCCOPY);

	DeleteDC(hdc);

}

void __fastcall TQCam::Timer1Timer(TObject *Sender)

{

	PaintBox1->Repaint();

	capGrabFrameNoStop(hWndC);

}