type 
  EMyMCIException = class(Exception); 

var 
  FDeviceID: Word; 
  MyError, dwFlags: Longint; 

procedure TForm1.GetWaveLength; 
var 
  WaveLen: DWORD; 
begin 
  OpenMedia('C:\Hickory.wav'); 
  SetMediaTimeFormat; 
  WaveLen := GetMediaStatus(MCI_STATUS_LENGTH); 
  CloseMedia; 
  Form1.label1.Caption := IntToStr(WaveLen) + 'mS'; 
end; 

procedure TForm1.OpenMedia(FileName: string); 
var 
  MyOpenParms: TMCI_Open_Parms; 
begin 
  with MyOpenParms do 
  begin 
    dwCallback := Handle; // TForm1.Handle 
    lpstrDeviceType := PChar('WaveAudio'); 
    lpstrElementName := PChar(FileName); 
  end; {with MyOpenParms} 
  dwFlags := MCI_WAIT or MCI_OPEN_ELEMENT or MCI_OPEN_TYPE; 
  MyError := mciSendCommand(0, MCI_OPEN, dwFlags, Longint(@MyOpenParms)); 
  // one could use mciSendCommand(DevId, etc here to specify a particular 
  device 
  if MyError = 0 then 
    FDeviceID := MyOpenParms.wDeviceID 
  else 
    raise EMyMCIException.Create('Open Failed'); 
end; 

procedure TForm1.SetMediaTimeFormat; 
var 
  MySetParms: TMCI_Set_Parms; 
begin 
  if FDeviceID <> 0 then 
  begin 
    dwFlags := MCI_WAIT or MCI_SET_TIME_FORMAT; 
    MySetParms.dwCallback := Handle; // TForm1.Handle 
    MySetParms.dwTimeFormat := MCI_FORMAT_MILLISECONDS; 
    MyError := mciSendCommand(FDeviceID, MCI_SET, dwFlags, 
      Longint(@MySetParms)); 
    if MyError <> 0 then 
      raise EMyMCIException.Create('Status Failed'); 
  end; 
end; 

function TForm1.GetMediaStatus(StatusItem: DWORD): DWORD; 
var 
  MyStatusParms: TMCI_Status_Parms; 
begin 
  if FDeviceID <> 0 then 
  begin 
    dwFlags := MCI_WAIT or MCI_STATUS_ITEM; 
    MyStatusParms.dwCallback := Handle; // TForm1.Handle 
    MyStatusParms.dwItem := StatusItem; 
    MyError := mciSendCommand(FDeviceID, MCI_STATUS, dwFlags, 
      Longint(@MyStatusParms)); 
    if MyError = 0 then 
      Result := MyStatusParms.dwReturn 
    else 
    begin 
      raise EMyMCIException.Create('Status Failed'); 
    end; 
  end; 
end; 

procedure TForm1.CloseMedia; 
var 
  MyGenParms: TMCI_Generic_Parms; 
begin 
  if FDeviceID <> 0 then 
  begin 
    dwFlags := 0; 
    MyGenParms.dwCallback := Handle; // TForm1.Handle 
    MyError := mciSendCommand(FDeviceID, MCI_CLOSE, dwFlags, 
      Longint(@MyGenParms)); 
    if MyError = 0 then 
      FDeviceID := 0 
    else 
    begin 
      raise EMyMCIException.Create('Close Failed'); 
    end; 
  end; 
end;