Thread: How to mute microphone in mixer?

Here is a little function, assembled from code in a CodeProject article.

Code:

#include <windows.h>

#if defined(_MSC_VER)
#pragma comment(lib, "Winmm.lib")
#endif

/* 
 * Function to mute or unmute the system microphone.
 * Arg: fMute - TRUE to mute, FALSE to unmute.
 */
BOOL MuteMicrophone(BOOL fMute)
{
	MMRESULT                    result   = 0;
	HMIXER                      hMixer   = 0;
	MIXERLINE                   ml       = { 0 };
	MIXERLINECONTROLS           mlc      = { 0 };
	MIXERCONTROL                mc       = { 0 };
	MIXERCONTROLDETAILS_BOOLEAN mcb      = { 0 };
	MIXERCONTROLDETAILS         mcd      = { 0 };

	result = mixerOpen(&hMixer, MIXER_OBJECTF_MIXER, 0, 0, 0);

	ml.cbStruct        = sizeof(MIXERLINE);
	ml.dwComponentType = MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE ;
	result = mixerGetLineInfo((HMIXEROBJ) hMixer, &ml, MIXER_GETLINEINFOF_COMPONENTTYPE);

	mlc.cbStruct      = sizeof(MIXERLINECONTROLS);
	mlc.dwLineID      = ml.dwLineID;
	mlc.dwControlType = MIXERCONTROL_CONTROLTYPE_MUTE;
	mlc.cControls     = 1;
	mlc.pamxctrl      = &mc;
	mlc.cbmxctrl      = sizeof(MIXERCONTROL);
	result = mixerGetLineControls((HMIXEROBJ) hMixer, &mlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);

	mcd.cbStruct    = sizeof(MIXERCONTROLDETAILS);
	mcd.hwndOwner   = NULL;
	mcd.dwControlID = mc.dwControlID;
	mcb.fValue      = fMute;
	mcd.paDetails   = &mcb;
	mcd.cbDetails   = sizeof(MIXERCONTROLDETAILS_BOOLEAN);
	mcd.cChannels   = 1;
	result = mixerSetControlDetails((HMIXEROBJ) hMixer, &mcd, MIXER_SETCONTROLDETAILSF_VALUE);

	mixerClose(hMixer);

	return (result == MMSYSERR_NOERROR ? TRUE : FALSE);

}

int main(void)
{
	MuteMicrophone(TRUE);

	return 0;
}

The Mixer API has got to be the messiest API in Win32. I can only assume that is was designed by the work experience kid while he was smoking some seriously good stuff.

Its my understanding that SRC_MICROPHONE will only mute/unmute the ECHO of whats entered. Correct me if im wrong here. Im trying to shut off the microphones input to the system.

Originally Posted by DeepBlackMagic

Its my understanding that SRC_MICROPHONE will only mute/unmute the ECHO of whats entered. Correct me if im wrong here. Im trying to shut off the microphones input to the system.

I'm not sure. Can you try it? I don't have a microphone handy.