Как показать видео на полном экране?

procedure TForm1.Button1Click(Sender: TObject);
const
  longName: PChar = 'f:\media\ANIM1.MPG'; {Your complete FileName}
var
  ret, shortName: PChar;
  err: DWord;
begin
  {Getting the short Name (8:3) of selected file}
  shortName := strAlloc(521);
  GetShortPathName(longName, shortname, 512);
  {Sending a close Command to the MCI}
  ret := strAlloc(255);
  err := mciSendString(pchar('close movie'), 0, 0, 0);
  {No error check because at the first call there is no MCI device to close}
  {Open a new MCI Device with the selected movie file}
  err := mciSendString(pchar('open ' + shortName + ' alias movie'), 0, 0, 0);
  shortName := nil;
  {If an Error was traced then display a MessageBox with the mciError string}
  if err <> 0 then
  begin
    mciGetErrorString(err, ret, 255);
    messageDlg(ret, mtInformation, [mbOk], 0);
  end;
  {Sending the "play fullscreen command to the Windows MCI}
  err := mciSendString(pchar('play movie fullscreen'), 0, 0, 0);
  {Use the following line instead of the above one if you want to play 
        it in screen mode}
  err := mciSendString(pchar('play movie'), 0, 0, 0);
  {If an Error was traced then display a MessageBox with the mciError string}
  if err <> 0 then
  begin
    mciGetErrorString(err, ret, 255);
    messageDlg(ret, mtInformation, [mbOk], 0);
  end;
  ret := nil;
end;

Взято с Delphi Knowledge Base: https://www.baltsoft.com/