Get/Set Master Volume Lautstärke?

[Kas Ob.]

Zitat von PeterPanino:

The user should always be in control of his computer's sound!

Sure but Windows lack ability to do permissions like iOS or Android so they revert to prohibit some API without explicitly user inatraction.

I was mistaken with the mute status, my old project was on specific request from a client where he wanted to control the devices in Sound Control Panel to enable and disable a device and change the Default device for both Playback and Recording, which is not allowed without user interaction, it took me hours of debugging to extract the Windows internal code which was one freaking line!!

Anyway i tried this based on your code and it is working just fine

Code:

procedure TForm10.SetMasterMuteState(Muted: Boolean);
var
  MuteStatus: Boolean;
  FAudioEndpointVolume: AudioEndpoint.IAudioEndpointVolume; // from the Andreas Rejbrand unit
  FDeviceEnumerator: IMMDeviceEnumerator;
  FMMDevice: IMMDevice;
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_IAudioEndpointVolume, CLSCTX_INPROC_SERVER, nil,
    FAudioEndpointVolume)) then
  begin
    OutputDebugString('TForm1.SetMasterVolumeLevelScalar: 3');
      //CodeSite.Send('TForm1.SetMasterVolumeLevelScalar: 3');
    ExitProcess(1);
  end;

  if Assigned(FAudioEndpointVolume) then
  begin
    if not Succeeded(FAudioEndpointVolume.SetMute(Muted, nil)) then
      OutputDebugString(PChar('TForm1.SetMasterVolumeLevelScalar: SetMute OK ' + BoolToStr
        (Muted, True)))
    else
      OutputDebugString(PChar('TForm1.SetMasterVolumeLevelScalar: SetMute Fail ' +
        BoolToStr(Muted, True)))
  end
  else
  begin
    OutputDebugString('TForm1.SetMasterVolumeLevelScalar: FAudioEndpointVolume not assigned!');
      //CodeSite.Send('TForm1.SetMasterVolumeLevelScalar: FAudioEndpointVolume not assigned!');
  end;
end;

It is working on my Windows 10 (1803)