failed to call `ActivateAudioInterfaceAsync` , HRESULT: -2147417850

Question

failed to call `ActivateAudioInterfaceAsync` , HRESULT: -2147417850

TianpingHsu 26

Hi, I try to record the system audio by using applicationloopbackaudio-sample, it's ok; Then, I just compile it as a dll (exporting some interfaces) and link it to my GUI(QT) project (multithreading), however, when I call StartCaptureAsyn , I just get the error code: -2147417850 (0x80010106) ((failed in ActivateAudioInterfaceAsync);

Actually, it sometimes works fine, most times not; And if I try to adjust the function call position (say my app initializtion place), it works; if I put it into a callback function (say click a button, call the StartCaptureAsync), it may not work. I don't know why.

I googled, but can't find a solution; May I get some help here? Many thanks.

Viorel 122.9K Reputation points

2022-12-08T06:45:03.96+00:00

Did you also find the recommendation to call CoInitialize(NULL) in your executable or threads?
TianpingHsu 26 Reputation points

2022-12-08T07:43:03.81+00:00

Did you mean I should call the CoInitilize(NULL) when I create a CLoopbackCapture object? In my code, I create a static CLoopbackCapture Object in the dll, and call the StartCaptureAsync in my UI thread (I don't think there's any CoInitilize(NULL) in the UI thread).

As for the static CLoopbackCapture Object in the dll, the class CLoopbackCapture can't be newed; if I new a CLoopbackCapture Object, I get a compiler error: DoNotUseNewUseMake::operator new.

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Viorel 122.9K Reputation points

2022-12-08T06:45:03.96+00:00

Did you also find the recommendation to call CoInitialize(NULL) in your executable or threads?
TianpingHsu 26 Reputation points

2022-12-08T07:43:03.81+00:00

Did you mean I should call the CoInitilize(NULL) when I create a CLoopbackCapture object? In my code, I create a static CLoopbackCapture Object in the dll, and call the StartCaptureAsync in my UI thread (I don't think there's any CoInitilize(NULL) in the UI thread).

As for the static CLoopbackCapture Object in the dll, the class CLoopbackCapture can't be newed; if I new a CLoopbackCapture Object, I get a compiler error: DoNotUseNewUseMake::operator new.

Answer 1

Xiaopo Yang - MSFT 12,731 Microsoft External Staff

Hello,

Welcome to Microsoft Q&A!

RPC_E_CHANGED_MODE indicates A previous call to CoInitializeEx specified the concurrency model for this thread as multithread apartment (MTA). This could also indicate that a change from neutral-threaded apartment to single-threaded apartment has occurred.

Edit:
According to ActivateAudioInterfaceAsync ,

For many implementations, an application must call this function from the main UI thread to activate a COM interface in the WASAPI family so that the system can show a dialog to the user. Except

Calling ActivateAudioInterfaceAsync with a deviceInterfacePath that specifies an audio render device and an riid that specifies the IAudioClient interface.

Calling ActivateAudioInterfaceAsync with a deviceInterfacePath that specifies an audio render device and an riid that specifies the IAudioEndpointVolume interface.

Calling ActivateAudioInterfaceAsync from a session 0 service.

and

On versions of Windows previous to Windows 10, ActivateAudioInterfaceAsync must be called on a thread in a COM Single-Threaded Apartment (STA), when opening a device for audio capture.

Thank you.

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TianpingHsu 26 Reputation points

2022-12-08T09:16:08.767+00:00
Thank you for your answer and the link, but I still have some questions:

I just call the ActivateAudioInterfaceAsync interface in the dynamic link library, and the applicationloopbackaudio-sample does not call any CoInitilize[Ex], why this error(RPC_E_CHANGED_MODE) happends?

what I really want to do is to click a button and start capture system audio by calling my dll interface, how should I fix this problem?

Thanks.
RLWA32 49,901 Reputation points

2022-12-08T15:24:42.217+00:00

As a test try initializing the main thread of the MS sample code as an STA thread by calling CoInitialize(NULL) before the call to CLoopbackCapture::StartCaptureAsync. Does this cause RPC_E_CHANGED_MODE errors in the sample?
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2022-12-09T02:55:16.743+00:00

Calling CoInitialize in the sample main thread doesn't cause RPC_E_CHANGED_MODE. @TianpingHsu According to ActivateAudioInterfaceAsync ,

For many implementations, an application must call this function from the main UI thread to activate a COM interface in the WASAPI family so that the system can show a dialog to the user.

and

On versions of Windows previous to Windows 10, ActivateAudioInterfaceAsync must be called on a thread in a COM Single-Threaded Apartment (STA), when opening a device for audio capture.
TianpingHsu 26 Reputation points

2022-12-09T07:51:06.133+00:00
Hi, calling CoInitialize does not seem to solve my problem, I still get the same error: -2147417850 (0x80010106)

following code works fine, I get what I want:

however, this one does not work, (click button, set g_systemAudioCaptureCmd to 1, and signal it):
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2022-12-09T07:58:43.36+00:00

Calling CoInitialize does not surely solve the problem. According to ActivateAudioInterfaceAsync ,

For many implementations, an application must call this function from the main UI thread to activate a COM interface in the WASAPI family so that the system can show a dialog to the user.
TianpingHsu 26 Reputation points

2022-12-09T08:16:36.927+00:00

Hi, I tried to call START_CAPTURE in the main UI thread, it has the same problem:

Edit:
I just tried for several times, sometimes it works, sometimes it does not.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2022-12-09T08:56:16.037+00:00

Can you use a simple Windows Desktop application (C++) to reproduce and show the sample with GitHub or something else?
TianpingHsu 26 Reputation points

2022-12-10T07:00:53.917+00:00

May build a simple QT application (a window with two buttons) to demonstrate this question?
RLWA32 49,901 Reputation points

2022-12-10T09:21:20.32+00:00

A benefit of producing a sample that reproduces the issue without reliance on Qt is that it eliminates that framework as a possible source of the problem. On the other hand, if you cannot produce a Windows application that reproduces the issue without using Qt then perhaps the framework plays a part in causing the problem.
TianpingHsu 26 Reputation points

2022-12-11T10:17:38.117+00:00

Hi, I just find that the int main function calls another function initIMMDeviceEnumerator, which calls ::CoInitialize(NULL), does that matters?
I mean if I don't call initIMMDeviceEnumerator, CLoopbackCapture works fine, but I don't know why.
Xiaopo Yang - MSFT 12,731 Reputation points Microsoft External Staff

2022-12-14T01:58:47.223+00:00

It does cause the apartment inconsistent. You can try CoInitializeEx(NULL, COINIT_MULTITHREADED) to make them consistent.
TianpingHsu 26 Reputation points

2022-12-14T02:31:48.303+00:00

I appreciate your help very much, your comment fix my problem. Again thank you for your patience.

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failed to call `ActivateAudioInterfaceAsync` , HRESULT: -2147417850

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