uses mmsystem; 
 
function WaveLaenge(datei: string): double; 
var 
  i: integer; 
  r: array[0..29] of char; 
  procedure aus; 
  begin 
    MCISendString(pchar('stop wavsound'), nil, 0, 0); 
    MCISendString(pchar('close wavsound'), nil, 0, 0); 
  end; 
begin 
aus; 
 MCISendString(pchar('open ' + datei + ' type waveaudio alias wavsound'), nil, 0, 0); 
 i := MCISendString(pchar('status wavsound length'), r, 30, 0); 
 if i = 0 then result := strtoint(r) / 1000 
 else result := -1; 
aus; 
end; 
 
 
// Beispielaufruf 
 
procedure TForm1.Button3Click(Sender: TObject); 
var 
  d: double; 
  s, n: string; 
begin 
  s := 'c:\drums.wav'; 
  d := wavelaenge(s); 
  n := ansiuppercase(extractfilename(s) + ':  '); 
  if d = -1 then showmessage(n + 'Länge konnte nicht ermittelt werden.') else 
    showmessage(n + formatfloat('#,##0.000 Sekunden', d));
end;

uses mmsystem;  
 
var 
  dwFlags: DWord; 
  IDDevice: MCIDEVICEID = 0; 
 
function OpenWave(datei: string): MCIERROR; 
var 
  oParms: tagMCI_OPEN_PARMSA; 
begin 
  with oParms do begin 
    dwCallback := 0; 
    lpstrDeviceType := 'WaveAudio'; 
    lpstrElementName := PChar(datei); 
  end; 
  dwFlags := MCI_WAIT or MCI_OPEN_ELEMENT or MCI_OPEN_TYPE; 
  result := mciSendCommand(0, MCI_OPEN, dwFlags, DWord(@oParms)); 
  if result = 0 then IDDevice := oParms.wDeviceID; 
  mciSendCommand(oParms.wDeviceID, MCI_PLAY, MCI_WAIT, DWord(@oParms)); 
end; 
 
procedure CloseWave; 
var 
  gParms: tagMCI_GENERIC_PARMS; 
begin 
  if IDDevice > 0 then begin 
    dwFlags := 0; 
    gParms.dwCallback := 0; 
    mciSendCommand(IDDevice, MCI_CLOSE, dwFlags, DWord(@gParms)); 
  end; 
end; 
 
function GetStatus(Statusq: DWord): DWord; 
var 
  sParms: tagMCI_STATUS_PARMS; 
begin 
  dwFlags := MCI_WAIT or MCI_STATUS_ITEM; 
  sParms.dwCallback := 0; 
  sParms.dwItem := Statusq; 
  if not mciSendCommand(IDDevice, MCI_STATUS, 
    dwFlags, DWord(@sParms)) = 0 then begin 
    CloseWave; 
    raise exception.create('Status konnte nicht ermittelt werden'); 
  end else result := sParms.dwReturn; 
end; 
 
procedure TForm1.Button5Click(Sender: TObject); 
begin 
  Listbox1.clear; 
  if OpenDialog1.Execute then begin 
    if OpenWave(OpenDialog1.FileName) = 0 then begin 
      with ListBox1.Items do begin 
        Add('FormatTag: ' + 
          IntToStr(GetStatus(MCI_WAVE_STATUS_FORMATTAG))); 
        Add('Channels: ' + 
          IntToStr(GetStatus(MCI_WAVE_STATUS_CHANNELS))); 
        Add('SamplesPerSec: ' + 
          IntToStr(GetStatus(MCI_WAVE_STATUS_SAMPLESPERSEC))); 
        Add('AvgBytesPerSec: ' + 
          IntToStr(GetStatus(MCI_WAVE_STATUS_AVGBYTESPERSEC))); 
        Add('BlockAlign: ' + 
          IntToStr(GetStatus(MCI_WAVE_STATUS_BLOCKALIGN))); 
        Add('BitsPerSample: ' + 
          IntToStr(GetStatus(MCI_WAVE_STATUS_BITSPERSAMPLE))); 
        Add('Length (Sec.): ' + 
          formatfloat('#,##0.000', GetStatus(MCI_STATUS_LENGTH) / 1000)); 
      end; 
      CloseWave; 
    end else raise exception.create('Fehler beim Öffnen'); 
  end; 
end;