Bdtyktl

I am using the following code to capture a still image from a webcam. The only thing i have is a black screen, where the image is assumed to be displayed. I checked on my pc and found four avicap32.dll in different places. Is this normal?

private

{Private declarations }

hWndC : THandle ;

CapturingAVI : bool ; 



public {Public declarations }  end ;



var Form1: TForm1 ;



implementation



{$R *.DFM}



const WM_CAP_START                  =      WM_USER;

const WM_CAP_STOP                   = WM_CAP_START + 68;

const WM_CAP_DRIVER_CONNECT         = WM_CAP_START + 10;

 const WM_CAP_DRIVER_DISCONNECT      = WM_CAP_START + 11;

const WM_CAP_SAVEDIB                = WM_CAP_START + 25;

const WM_CAP_GRAB_FRAME             = WM_CAP_START + 60;

const WM_CAP_SEQUENCE               = WM_CAP_START + 62;

const WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START +  20;



function capCreateCaptureWindowA(lpszWindowName : PCHAR; dwStyle : longint; x : integer; y : integer; nWidth : integer; nHeight : integer;  ParentWin  : HWND;  nId : integer): HWND; STDCALL EXTERNAL 'AVICAP32.DLL';

procedure TForm1.FormCreate(Sender:TObject);

begin

CapturingAVI := false ;

 hWndC := 0;

 SaveDialog1.Options := [ofHideReadOnly, ofNoChangeDir,    ofPathMustExist]

end ;



procedure TForm1.OpenVideoClick(Sender: TObject);

begin

hWndC := capCreateCaptureWindowA('My. Own Capture Window', WS_CHILD or WS_VISIBLE , Panel1.Left, Panel1.Top, Panel1.Width, Panel1.Height, Form1.Handle, 0);   

if hWndC <> 0 then SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0) ;

end ;



procedure TForm1.CloseVideoClick(Sender:TObject);

begin

if hWndC <> 0 then 

begin



SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0) ;

hWndC := 0 ;



 end ;



 end ;



 procedure TForm1.GrabFrameClick(Sender: TObject) ;



begin



if hWndC <> 0 then SendMessage(hWndC, WM_CAP_GRAB_FRAME, 0, 0) ;



end ;



procedure TForm1.SaveBMPClick(Sender: TObject);

begin

if hWndC <> 0 then 

    begin

    SaveDialog1.DefaultExt := 'bmp';

    SaveDialog1.Filter := 'Bitmap files.  (*.bmp)|*.bmp';

    if SaveDialog1.Execute then

    SendMessage(hWndC, WM_CAP_SAVEDIB, 0, longint(pchar(SaveDialog1.FileName)));

      end;

 end;



procedure TForm1.StartAVIClick(Sender: TObject);

begin

if hWndC <> 0 then 

begin

SaveDialog1.DefaultExt := 'avi';

SaveDialog1.Filter := 'AVI files (*.avi)|*.avi') ;

if SaveDialog1.Execute then

    begin

    CapturingAVI := true ;

    SendMessage(hWndC, WM_CAP_FILE_SET_CAPTURE_FILEA,  0, Longint(pchar(SaveDialog1.FileName))) ;



    SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0) ;

    end;



    end;



  end ;



procedure TForm1.StopAVIClick(Sender: TObject);

begin



 if hWndC <> 0 then 

  begin

  SendMessage(hWndC, WM_CAP_STOP, 0, 0) ;

 CapturingAVI := false ;

 end ;



 end ;



end`