DirectShow ---设置视频输出格式

  // configure output Video media type
  if VideoSourceFilter.FilterGraph <> nil then
  begin
    PinList := TPinList.Create(VideoSourceFilter as IBaseFilter);
    if VideoFormats.ItemIndex <> -1 then
      with (PinList.First as IAMStreamConfig) do
        SetFormat(VideoMediaTypes.Items[VideoFormats.ItemIndex].AMMediaType^);
    PinList.Free;
  end;