var
//сноска из SDK DIrectX
//The IAMVideoControl interface enables you to flip a picture horizontally and/or vertically, set up a stream so it can capture from an //external trigger (such as a camera button that the user pushes), simulate an external trigger in software, and list the available frame //rates. 

//Use this interface when your application runs on hardware that is capable of flipping and external triggering.


  AMVideoControl: IAMVideoControl; 
  PinList: TPinList;
  i: integer;
  hr:HRESULT;
  ip:IPin;
begin
  // Activate the filter graph, at this stage the source filters are added to the graph
  CaptureGraph.Active := true;

  // configure output Video media type
  if VideoSourceFilter.FilterGraph <> nil then
  begin
    PinList := TPinList.Create(VideoSourceFilter as IBaseFilter);
    try   // подсоединились к IAMVideoControl
      VideoSourceFilter.QueryInterface(IID_IAMVideoControl, AMVideoControl);
      // ищем пин позволяющий делать still изображения
      (CaptureGraph as IcaptureGraphBuilder2).FindPin(VideoSourceFilter,PINDIR_OUTPUT,@PIN_CATEGORY_STILL,0,False,0,ip);
      //задаем пину настройку срабатывать по внешнему триггеру
      AMVideoControl.SetMode(ip,VideoControlFlag_Trigger);

      if VideoFormats.ItemIndex <> -1 then
        begin
          with (PinList.First as IAMStreamConfig) do
            SetFormat(VideoMediaTypes.Items[VideoFormats.ItemIndex].AMMediaType);
        end;
    finally
      PinList.Free;
    end;
  end;

  // now render streams
  with CaptureGraph as IcaptureGraphBuilder2 do
  begin 
   //для того, чтобы отобразить still данные мначала мы должны получить поток либо через превью либо через capture
    if VideoSourceFilter.BaseFilter.DataLength > 0 then
      RenderStream(@PIN_CATEGORY_PREVIEW, 
                   nil,
                   VideoSourceFilter as IBaseFilter,
                   nil,
                   VideoWindow as IBaseFilter); // showing preview
   // передаем полученное изображение 
      hr:=RenderStream(@PIN_CATEGORY_STILL,
                       nil,
                       VideoSourceFilter as IBaseFilter,
                       nil,
                       SampleGrabber1 as IBaseFilter //transferring data to SampleGrabber1
                       );
  end;
  CaptureGraph.Play;

..........
// получили - сохранили :)
procedure TMainForm.SampleGrabber1Buffer(sender: TObject; SampleTime: Double;
  pBuffer: Pointer; BufferLen: Integer);
var
  bmp:TBitmap;
begin
  if CallBack.Checked then
  begin
    bmp:=TBitmap.Create;
    try
      bmp.Width:=1640;
      bmp.Height:=1480;
      SampleGrabber1.GetBitmap(bmp, pBuffer, BufferLen);
      bmp.SaveToFile('d:\Capt.bmp');
      Image.Canvas.Lock;
      Image.Picture.Assign(bmp);
    finally
      Image.Canvas.Unlock;
      FreeAndNil(bmp);
    end;
  end;
end;