Is it possible to get status or event when Device Microphone is using by application?

Question

Is it possible to get status or event when Device Microphone is using by application?
Recently I need to detect Microphone use status, eg, application use microphone to record a voice and I need to detect or get event from windows 10 to control something. so is any Microsoft API or example code can be refer to.

Answer 1

Hello @佳昌 邱 ,

First, you can use IMMDeviceEnumerator to get the audio endpoint associated with the microphone device, it is as a capture audio device when recording a voice. (An audio endpoint is a hardware device that captures or consumes audio data. )

IMMDeviceCollection* dCol = NULL;
hr = pEnumerator->EnumAudioEndpoints(eCapture, DEVICE_STATE_ACTIVE, &dCol);

Then you can get PKEY_Device_FriendlyName to determine whether it is the microphone device you are focusing on.

Finally, you can emulate active sessions are using the microphone device. And you can use RegisterAudioSessionNotification method registers the client to receive notifications of session events, including changes in the stream state.

More references: "Managing the Audio Session".

The following is an example for how to achieve the goal you can refer to:

BOOL IsMicrophoneRecording()  
{  
 // #1 Get the audio endpoint associated with the microphone device  
 HRESULT hr = S_OK;  
 IMMDeviceEnumerator* pEnumerator = NULL;  
 IAudioSessionManager2* pSessionManager = NULL;  
 BOOL result = FALSE;  
  
 CoInitialize(0);  
  
 // Create the device enumerator.  
 hr = CoCreateInstance(  
 __uuidof(MMDeviceEnumerator),  
 NULL, CLSCTX_ALL,  
 __uuidof(IMMDeviceEnumerator),  
 (void**)& pEnumerator);  
  
 IMMDeviceCollection* dCol = NULL;  
 hr = pEnumerator->EnumAudioEndpoints(eCapture, DEVICE_STATE_ACTIVE, &dCol);  
 UINT dCount;  
 hr = dCol->GetCount(&dCount);  
 for (UINT i = 0; i < dCount; i++)  
 {  
 IMMDevice* pCaptureDevice = NULL;  
 hr = dCol->Item(i, &pCaptureDevice);  
  
 IPropertyStore* pProps = NULL;  
 hr = pCaptureDevice->OpenPropertyStore(  
 STGM_READ, &pProps);  
  
 PROPVARIANT varName;  
 // Initialize container for property value.  
 PropVariantInit(&varName);  
  
 // Get the endpoint's friendly-name property.  
 hr = pProps->GetValue(  
 PKEY_Device_FriendlyName, &varName);  
  
 std::wstring nameStr(varName.pwszVal);  
  
 // #2 Determine whether it is the microphone device you are focusing on  
 std::size_t found = nameStr.find(L"Microphone");  
 if (found != std::string::npos)  
 {  
 // Print endpoint friendly name.  
 printf("Endpoint friendly name: \"%S\"\n", varName.pwszVal);  
  
 // Get the session manager.  
 hr = pCaptureDevice->Activate(  
 __uuidof(IAudioSessionManager2), CLSCTX_ALL,  
 NULL, (void**)& pSessionManager);  
 break;  
 }  
 }  
  
 // Get session state  
 if (!pSessionManager)  
 {  
 return (result = FALSE);  
 }  
  
 int cbSessionCount = 0;  
 LPWSTR pswSession = NULL;  
  
 IAudioSessionEnumerator* pSessionList = NULL;  
 IAudioSessionControl* pSessionControl = NULL;  
 IAudioSessionControl2* pSessionControl2 = NULL;  
  
 // Get the current list of sessions.  
 hr = pSessionManager->GetSessionEnumerator(&pSessionList);  
  
 // Get the session count.  
 hr = pSessionList->GetCount(&cbSessionCount);  
 //wprintf_s(L"Session count: %d\n", cbSessionCount);  
  
 for (int index = 0; index < cbSessionCount; index++)  
 {  
 CoTaskMemFree(pswSession);  
 SAFE_RELEASE(pSessionControl);  
  
 // Get the <n>th session.  
 hr = pSessionList->GetSession(index, &pSessionControl);  
  
 hr = pSessionControl->QueryInterface(  
 __uuidof(IAudioSessionControl2), (void**)& pSessionControl2);  
  
 // Exclude system sound session  
 hr = pSessionControl2->IsSystemSoundsSession();  
 if (S_OK == hr)  
 {  
 //wprintf_s(L" this is a system sound.\n");  
 continue;  
 }  
  
 // Optional. Determine which application is using Microphone for recording  
 LPWSTR instId = NULL;  
 hr = pSessionControl2->GetSessionInstanceIdentifier(&instId);  
 if (S_OK == hr)  
 {  
 wprintf_s(L"SessionInstanceIdentifier: %s\n", instId);  
 }  
  
 AudioSessionState state;  
 hr = pSessionControl->GetState(&state);  
 switch (state)  
 {  
 case AudioSessionStateInactive:  
 wprintf_s(L"Session state: Inactive\n", state);  
 break;  
 case AudioSessionStateActive:  
 // #3 Active state indicates it is recording, otherwise is not recording.  
 wprintf_s(L"Session state: Active\n", state);  
 result = TRUE;  
 break;  
 case AudioSessionStateExpired:  
 wprintf_s(L"Session state: Expired\n", state);  
 break;  
 }  
 }  
  
done:  
 // Clean up.  
 SAFE_RELEASE(pSessionControl);  
 SAFE_RELEASE(pSessionList);  
 SAFE_RELEASE(pSessionControl2);  
 SAFE_RELEASE(pSessionManager);  
 SAFE_RELEASE(pEnumerator);  
  
 return result;  
}  

Result based on above sample code:

Thank you!

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