How to mute microphone in Windows 7 with C/C++?

Question

I made a program to mute microphone using WinAPI and it seems to work perfectly in Windows XP but doesn't do a thing in Windows 7. Is it possible to control microphone volume or mute with WinAPI in Windows 7?

void setVolume(DWORD volume) {
HMIXER mixer;

if (mixerOpen(&mixer, 0, 0, 0, 0) != MMSYSERR_NOERROR) {
    MessageBoxW(NULL, L"Error: mixerOpen()", NULL, MB_ICONHAND);
    return;
}

// Get the line info
MIXERCAPS mixcaps;
MIXERLINE mixerLine;
mixerGetDevCaps(0, &mixcaps, sizeof(MIXERCAPS));
mixerLine.cbStruct = sizeof(MIXERLINE);
mixerLine.dwComponentType = MIXERLINE_COMPONENTTYPE_DST_WAVEIN;
mixerLine.dwSource = 0;
mixerLine.dwDestination = 0;

if (mixerGetLineInfo(reinterpret_cast<HMIXEROBJ>(mixer), &mixerLine, MIXER_GETLINEINFOF_SOURCE)
    != MMSYSERR_NOERROR) {
        MessageBoxW(NULL, L"Error: mixerGetLineInfo()", NULL, MB_ICONHAND);
        return;
}

// Get control for mixerline
MIXERCONTROL mixerCtrl;
MIXERLINECONTROLS mixerLineCtrl;

mixerLineCtrl.cbStruct = sizeof(MIXERLINECONTROLS);
mixerLineCtrl.dwLineID = mixerLine.dwLineID;
mixerLineCtrl.dwControlType = MIXERCONTROL_CONTROLTYPE_VOLUME;
mixerLineCtrl.cControls = 1;
mixerLineCtrl.pamxctrl = &mixerCtrl;
mixerLineCtrl.cbmxctrl = sizeof(MIXERCONTROL);
mixerLineCtrl.cControls = 5;

if (mixerGetLineControls(reinterpret_cast<HMIXEROBJ>(mixer), &mixerLineCtrl, MIXER_GETLINECONTROLSF_ONEBYTYPE)
    != MMSYSERR_NOERROR) {
        MessageBoxW(NULL, L"Error: mixerGetLineControls()", NULL, MB_ICONHAND);
        return;
}

// Volume..
MIXERCONTROLDETAILS mixerCtrlDetails;
MIXERCONTROLDETAILS_UNSIGNED mixerCtrlDetailsUnsigned;

mixerCtrlDetailsUnsigned.dwValue = volume;
mixerCtrlDetails.dwControlID = mixerCtrl.dwControlID;
mixerCtrlDetails.cbStruct = sizeof(MIXERCONTROLDETAILS);
mixerCtrlDetails.cMultipleItems = 0;
mixerCtrlDetails.paDetails = &mixerCtrlDetailsUnsigned;
mixerCtrlDetails.cbDetails = sizeof(MIXERCONTROLDETAILS_UNSIGNED);
mixerCtrlDetails.cChannels = 1;

if (mixerSetControlDetails(reinterpret_cast<HMIXEROBJ>(mixer), &mixerCtrlDetails, MIXER_OBJECTF_HMIXER | MIXER_GETCONTROLDETAILSF_VALUE)
    != MMSYSERR_NOERROR) {
        MessageBoxW(NULL, L"Error: mixerSetControlDetails()", NULL, MB_ICONHAND);
        return;
}

mixerClose(mixer);
}

Answer 1

You need to use the new audio APIs introduced by Windows Vista.

Here is an example.