如何使用C/C++在Windows 7中静音麦克风？

Question

我制作了一个使用WinAPI静音麦克风的程序，它似乎在Windows XP中完美工作，但在Windows 7中没有做到这一点。是否可以在Windows 7中使用WinAPI控制麦克风音量或静音？

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

您需要使用new audio APIs introduced by Windows Vista。

Here is an example。

*编辑：的Visual Studio 2015（C++）：

Usange：

// To 100% 
ConsoleApplication3.exe -f 1 

// To 0% 
ConsoleApplication3.exe -f 0 

// To 50% 
ConsoleApplication3.exe -f 0.50 

代码：

#include "stdafx.h" 
#include <stdio.h> 
#include <windows.h> 
#include <mmdeviceapi.h> 
#include <endpointvolume.h> 

void Usage() 
{ 
    printf("Usage: \n"); 
    printf(" SetVolume [Reports the current volume]\n"); 
    printf(" SetVolume -d <new volume in decibels> [Sets the current default render device volume to the new volume]\n"); 
    printf(" SetVolume -f <new volume as an amplitude scalar> [Sets the current default render device volume to the new volume]\n"); 

} 
int _tmain(int argc, _TCHAR* argv[]) 
{ 
    HRESULT hr; 
    bool decibels = false; 
    bool scalar = false; 
    double newVolume; 
    if (argc != 3 && argc != 1) 
    { 
     Usage(); 
     return -1; 
    } 
    if (argc == 3) 
    { 
     if (argv[1][0] == '-') 
     { 
      if (argv[1][1] == 'f') 
      { 
       scalar = true; 
      } 
      else if (argv[1][1] == 'd') 
      { 
       decibels = true; 
      } 
     } 
     else 
     { 
      Usage(); 
      return -1; 
     } 

     newVolume = _tstof(argv[2]); 
    } 

    // ------------------------- 
    CoInitialize(NULL); 
    IMMDeviceEnumerator *deviceEnumerator = NULL; 
    hr = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL, CLSCTX_INPROC_SERVER, __uuidof(IMMDeviceEnumerator), (LPVOID *)&deviceEnumerator); 
    IMMDevice *defaultDevice = NULL; 

    hr = deviceEnumerator->GetDefaultAudioEndpoint(eRender, eConsole, &defaultDevice); 
    deviceEnumerator->Release(); 
    deviceEnumerator = NULL; 

    IAudioEndpointVolume *endpointVolume = NULL; 
    hr = defaultDevice->Activate(__uuidof(IAudioEndpointVolume), CLSCTX_INPROC_SERVER, NULL, (LPVOID *)&endpointVolume); 
    defaultDevice->Release(); 
    defaultDevice = NULL; 

    // ------------------------- 
    float currentVolume = 0; 
    endpointVolume->GetMasterVolumeLevel(&currentVolume); 
    printf("Current volume in dB is: %f\n", currentVolume); 

    hr = endpointVolume->GetMasterVolumeLevelScalar(&currentVolume); 
    printf("Current volume as a scalar is: %f\n", currentVolume); 
    if (decibels) 
    { 
     hr = endpointVolume->SetMasterVolumeLevel((float)newVolume, NULL); 
    } 
    else if (scalar) 
    { 
     hr = endpointVolume->SetMasterVolumeLevelScalar((float)newVolume, NULL); 
    } 
    endpointVolume->Release(); 

    CoUninitialize(); 
    return 0; 
}