Mega Code Archive
How to mute the master volume of your soundcard
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Title: How to mute the master volume of your soundcard
uses
MMSystem;
function GetMasterMute(
Mixer: hMixerObj;
var Control: TMixerControl): MMResult;
// Returns True on success
var
Line: TMixerLine;
Controls: TMixerLineControls;
begin
ZeroMemory(@Line, SizeOf(Line));
Line.cbStruct := SizeOf(Line);
Line.dwComponentType := MIXERLINE_COMPONENTTYPE_DST_SPEAKERS;
Result := mixerGetLineInfo(Mixer, @Line,
MIXER_GETLINEINFOF_COMPONENTTYPE);
if Result = MMSYSERR_NOERROR then
begin
ZeroMemory(@Controls, SizeOf(Controls));
Controls.cbStruct := SizeOf(Controls);
Controls.dwLineID := Line.dwLineID;
Controls.cControls := 1;
Controls.dwControlType := MIXERCONTROL_CONTROLTYPE_MUTE;
Controls.cbmxctrl := SizeOf(Control);
Controls.pamxctrl := @Control;
Result := mixerGetLineControls(Mixer, @Controls,
MIXER_GETLINECONTROLSF_ONEBYTYPE);
end;
end;
procedure SetMasterMuteValue(
Mixer: hMixerObj;
Value: Boolean);
var
MasterMute: TMixerControl;
Details: TMixerControlDetails;
BoolDetails: TMixerControlDetailsBoolean;
Code: MMResult;
begin
Code := GetMasterMute(0, MasterMute);
if Code = MMSYSERR_NOERROR then
begin
with Details do
begin
cbStruct := SizeOf(Details);
dwControlID := MasterMute.dwControlID;
cChannels := 1;
cMultipleItems := 0;
cbDetails := SizeOf(BoolDetails);
paDetails := @BoolDetails;
end;
LongBool(BoolDetails.fValue) := Value;
Code := mixerSetControlDetails(0, @Details,
MIXER_SETCONTROLDETAILSF_VALUE);
end;
if Code MMSYSERR_NOERROR then
raise Exception.CreateFmt('SetMasterMuteValue failure, '+
'multimedia system error #%d', [Code]);
end;
// Example:
procedure TForm1.Button1Click(Sender: TObject);
begin
SetMasterMuteValue(0, CheckBox1.Checked); // Mixer device #0 mute on/off
end;
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