Program to video capture

[kk1...@o2.pl]

Hi,
I would like to write a program to capture video from a Webcam. I have
got Delphi 7 and Dspack component. I saw the demo programs, and I
found 3 programs, one let me preview video, the second make possible
to capture video, and the next let me save a bitmap file. I don’t know
how to join the 3 programs. In videocap demo I write a procedure from
ASF Capture, which shows preview:

CaptureGraph.ClearGraph;
CaptureGraph.Active := false;
VideoSourceFilter.BaseFilter.Moniker := CapEnum.GetMoniker(0);
CaptureGraph.Active := true;
with CaptureGraph as ICaptureGraphBuilder2 do
begin
CheckDSError(RenderStream(@PIN_CATEGORY_CAPTURE , nil,
VideoSourceFilter as IBaseFilter, nil, ASFWriter as IbaseFilter));
CheckDSError(RenderStream(@PIN_CATEGORY_PREVIEW , nil,
VideoSourceFilter as IBaseFilter, nil, VideoWindow as IbaseFilter));
end;
CaptureGraph.Play;

And it doesn’t work. Does someone know how I can write a program, that
has got 3 functions. Maybe has someone got a program, that does it. I
would be very graceful for help.