Volume set

var
MixerControl: TMixerControl;
MixerControlDetails: TMixerControlDetails;
MixerControlDetailsSigned: TMixerControlDetailsSigned;
Mixer: THandle;
MixerLine: TMixerLine;
MixerLineControls: TMixerLineControls;
PeakMeter: DWord;
Rslt: DWord;
SourceCount: Cardinal;
WaveOut: DWord;
I: Integer;
X: Integer;
Y: Integer;
begin
Rslt := mixerOpen(@Mixer, 0, 0, 0, 0);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t open mixer (%d)', [Rslt]);
FillChar(MixerLine, SizeOf(MixerLine), 0);
MixerLine.cbStruct := SizeOf(MixerLine);
MixerLine.dwComponentType := MIXERLINE_COMPONENTTYPE_DST_SPEAKERS;
Rslt := mixerGetLineInfo(Mixer, @MixerLine,
MIXER_GETLINEINFOF_COMPONENTTYPE);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t find speaker line (%d)', [Rslt]);
SourceCount := MixerLine.cConnections;
WaveOut := $FFFFFFFF;
for I := 0 to SourceCount - 1 do
begin
MixerLine.dwSource := I;
Rslt := mixerGetLineInfo(Mixer, @MixerLine,
MIXER_GETLINEINFOF_SOURCE);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t get source line (%d)', [Rslt]);
if MixerLine.dwComponentType = MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT
then
begin
WaveOut := MixerLine.dwLineId;
Break;
end;
end;
if WaveOut = $FFFFFFFF then
raise Exception.Create('Can''t find wave out device');
FillChar(MixerLineControls, SizeOf(MixerLineControls), 0);
with MixerLineControls do
begin
cbStruct := SizeOf(MixerLineControls);
dwLineId := WaveOut;
dwControlType := MIXERCONTROL_CONTROLTYPE_PEAKMETER;
cControls := 1;
cbmxctrl := SizeOf(TMixerControl);
pamxctrl := @MixerControl;
end;
Rslt := mixerGetLineControls(Mixer, @MixerLineControls,
MIXER_GETLINECONTROLSF_ONEBYTYPE);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t find peak meter control (%d)',
[Rslt]);
PeakMeter := MixerControl.dwControlID;

// at this point, I have the meter control ID, so I can
// repeatedly query its value and plot the resulting data
// on a canvas

X := 0;
FillChar(MixerControlDetails, SizeOf(MixerControlDetails), 0);
with MixerControlDetails do
begin
cbStruct := SizeOf(MixerControlDetails);
dwControlId := PeakMeter;
cChannels := 1;
cbDetails := SizeOf(MixerControlDetailsSigned);
paDetails := @MixerControlDetailsSigned;
end;
repeat
Sleep(10);
Rslt := mixerGetControlDetails(Mixer, @MixerControlDetails,
MIXER_GETCONTROLDETAILSF_VALUE);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t get control details (%d)',
[Rslt]);
Application.ProcessMessages;
Inc(X);
Y := 300 - Round(300 * Abs(MixerControlDetailsSigned.lValue) /
32768);
with Canvas do
begin
MoveTo(X, 0);
Pen.Color := clBtnFace;
LineTo(X, 300);
Pen.Color := clWindowText;
LineTo(X, Y);
end;
until X > 500;

// don't forget to close the mixer handle when you're done

Rslt := mixerClose(Mixer);
if Rslt <> 0 then
raise Exception.CreateFmt('Can''t close mixer (%d)', [Rslt]);
end;


http://torry.net/pages.php?id=186

http://www.swissdelphicenter.ch/en/showcode.php?id=225

{1.}

uses
  MMSystem;

procedure SetVolume(const volL, volR: Word);
var
  hWO: HWAVEOUT;
  waveF: TWAVEFORMATEX;
  vol: DWORD;
begin
  // init TWAVEFORMATEX
  FillChar(waveF, SizeOf(waveF), 0);
  // open WaveMapper = std output of playsound
  waveOutOpen(@hWO, WAVE_MAPPER, @waveF, 0, 0, 0);
  vol := volL + volR shl 16;
  // set volume
  waveOutSetVolume(hWO, vol);
  waveOutClose(hWO);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  SetVolume(14000, 14000);
end;


{************************************************}

{2.}

{by Serhiy Perevoznyk}

uses
  MMSystem;


function GetVolumeControl(aMixer: HMixer; componentType, ctrlType: Longint;
  var mxc: TMixerControl): Boolean;
var
  mxl: TMixerLine;
  mxlc: TMixerLineControls;
  rc: Longint;
begin
  Result := False;
  FillChar(mxl, SizeOf(TMixerLine), 0);
  mxl.cbStruct := SizeOf(TMixerLine);
  mxl.dwComponentType := componentType;
  {Obtain a line corresponding to the component type}
  rc := mixerGetLineInfo(aMixer, @mxl, MIXER_GETLINEINFOF_COMPONENTTYPE);
  if rc = MMSYSERR_NOERROR then
  begin
    with mxlc do
    begin
      cbStruct := SizeOf(TMixerLineControls);
      dwLineID := mxl.dwLineID;
      dwControlType := ctrlType;
      cControls := 1;
      cbmxctrl := SizeOf(TMixerLine);
      pamxctrl := @mxc;
      pamxctrl^.cbStruct := SizeOf(TMixerControl);
    end;
    mixerGetLineControls(aMixer, @mxlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);
    rc := mixerGetLineControls(aMixer, @mxlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);
    Result := rc = MMSYSERR_NOERROR;
  end;
end;

function SetVolumeControl(aMixer: HMixer; mxc: TMixerControl; volume: Longint): Boolean;
var
  mxcd: TMixerControlDetails;
  vol: TMixerControlDetails_Unsigned;
  rc: MMRESULT;
begin
  FillChar(mxcd, SizeOf(mxcd), 0);
  with mxcd do
  begin
    cbStruct := SizeOf(TMixerControlDetails);
    dwControlID := mxc.dwControlID;
    cbDetails := SizeOf(TMixerControlDetails_Unsigned);
    paDetails := @vol;
    cMultipleItems := 0;
    cChannels := 1;
  end;
  vol.dwValue := volume;
  rc := mixerSetControlDetails(aMixer, @mxcd, MIXER_SETCONTROLDETAILSF_VALUE);
  Result := rc = MMSYSERR_NOERROR;
end;

function InitMixer: HMixer;
var
  Err: MMRESULT;
begin
  Err := mixerOpen(@Result, 0, 0, 0, 0);
  if Err <> MMSYSERR_NOERROR then
    Result := 0;
end;

// Example:


procedure SetMasterVolumeToZero;
var
  MyMixerHandle: HMixer;
  MyVolCtrl: TMixerControl;
begin
  MyMixerHandle := InitMixer;
  if MyMixerHandle <> 0 then
    try
      FillChar(MyVolCtrl, SizeOf(MyVolCtrl), 0);
      if GetVolumeControl(MyMixerHandle, MIXERLINE_COMPONENTTYPE_DST_SPEAKERS,
        MIXERCONTROL_CONTROLTYPE_VOLUME, MyVolCtrl) then
      begin
        {The last parameter (0) here is the volume level}
        if SetVolumeControl(MyMixerHandle, MyVolCtrl, 0) then
          ShowMessage('Volume should now be set to zero');
      end;
    finally
      mixerClose(MyMixerHandle);
    end;
end;


procedure TForm1.Button2Click(Sender: TObject);
begin
 SetMasterVolumeToZero
end;