Get/Set Master Volume Lautstärke?

[Kas Ob.]

Interesting !

Please try this

Code:

const
  IID_IAudioEndpointVolumeEx: TGUID = '{66E11784-F695-4F28-A505-A7080081A78F}';

type
  IAudioEndpointVolumeEx = interface(IAudioEndpointVolume)
    [IID_IAudioEndpointVolumeEx]
    function GetVolumeRangeChannel(nChannel: Integer; out pflVolumeMindB: double; out
      pflVolumeMaxdB: double; out pflVolumeIncrementdB: double): HRESULT; stdcall;
  end;

procedure TForm10.Button3Click(Sender: TObject);
begin
  SetMasterMuteState(True);
end;

procedure TForm10.Button4Click(Sender: TObject);
begin
  SetMasterMuteState(False);
end;

procedure TForm10.SetMasterMuteState(Muted: Boolean);
var
  FAudioEndpointVolumeEx: IAudioEndpointVolumeEx;
  FDeviceEnumerator: IMMDeviceEnumerator;
  FMMDevice: IMMDevice;
  R: System.HResult;
begin
  if not Succeeded(CoCreateInstance(CLASS_IMMDeviceEnumerator, nil, CLSCTX_INPROC_SERVER,
    IID_IMMDeviceEnumerator, FDeviceEnumerator)) then
  begin
    OutputDebugString('TForm1.SetMasterVolumeLevelScalar: 1');
      //CodeSite.Send('TForm1.SetMasterVolumeLevelScalar: 1');
    ExitProcess(1);
  end;

  if not Succeeded(FDeviceEnumerator.GetDefaultAudioEndpoint(0, 0, FMMDevice)) then
  begin
    OutputDebugString('TForm1.SetMasterVolumeLevelScalar: 2');
      //CodeSite.Send('TForm1.SetMasterVolumeLevelScalar: 2');
    ExitProcess(1);
  end;

  if not Succeeded(FMMDevice.Activate(IID_IAudioEndpointVolumeEx, CLSCTX_INPROC_SERVER,
    nil, IAudioEndpointVolume(FAudioEndpointVolumeEx))) then
  begin
    OutputDebugString('TForm1.SetMasterVolumeLevelScalar: 3');
      //CodeSite.Send('TForm1.SetMasterVolumeLevelScalar: 3');
    ExitProcess(1);
  end;

  if Assigned(FAudioEndpointVolumeEx) then
  begin
    R := FAudioEndpointVolumeEx.SetMute(Muted, nil);
    case R of
      S_OK:
        OutputDebugString('TForm1.SetMasterVolumeMuteState: OK'); // successful operation with a return value of True
      S_FALSE:
        OutputDebugString('TForm1.SetMasterVolumeMuteState: FALSE'); // successful operation with a return value of False
      E_NOINTERFACE:
        OutputDebugString('TForm1.SetMasterVolumeMuteState: NOINTERFACE'); // Interface not supported
      E_UNEXPECTED:
        OutputDebugString('TForm1.SetMasterVolumeMuteState: UNEXPECTED'); // Catastrophic failure
      E_NOTIMPL:
        OutputDebugString('TForm1.SetMasterVolumeMuteState: NOTIMPL'); // Operation not implemented
    else
      OutputDebugString(PChar('TForm1.SetMasterVolumeMuteState: ELSE ' + IntToStr(R)));
    end;

  end
  else
  begin
    OutputDebugString('TForm1.SetMasterVolumeLevelScalar: FAudioEndpointVolume not assigned!');
      //CodeSite.Send('TForm1.SetMasterVolumeLevelScalar: FAudioEndpointVolume not assigned!');
  end;
end;

Also did you try to run your application as Administrator ? , it could be some permission problem.