[Khronos]

Código Delphi [-]
var
UpdateTrack: boolean; //tiene que ser una variable global

procedure TForm1.Timer1Timer(Sender: TObject);
begin
UpdateTrack := true;
trackbar1.Position:=mediaplayer1.Position;
...
end;

procedure TFPrincipal.TrackBar1Change(Sender: TObject);
begin
//comprobar si hay algo reproduciendo
if mediaplayer1.Mode=mpplaying then begin

if not UpdateTrack then begin
    MediaPlayer1.Position := TrackBar1.Position;
    MediaPlayer1.Play;
    ...
  end else
    UpdateTrack := false;
end;
end;

Salu2