在Win7上，在默认端点上轮询音频会话有时会崩溃

Question

我正在开发一个应用程序，该应用程序每隔X毫秒在默认音频渲染端点上轮询音频会话的状态和峰值级别，并在此基础上实现一些逻辑。它在Windows 10上似乎运行良好，但在Windows 7上，当我更改默认播放设备时(例如，当我在USB耳机和PC扬声器之间切换时(，我偶尔会崩溃。崩溃发生的确切行在运行之间会发生变化，但通常是在我访问IAudioSessionControl或IAudioSsessionControl2指针进行各种WASAPI调用时。我可以从ProcDump创建并由WinDbg分析的堆栈跟踪中了解到，当默认播放设备发生更改时，表示音频会话的COM对象会被破坏(尽管我已经获得并仍然持有指向这些对象接口的指针(，然后我的轮询线程在我通过接口指针访问它们的地方随机崩溃。我想也许我做错了什么，所以这让我找到了Matthew van Eerde的博客和sample，在那里他进行相同的查询(以及更多(，但针对系统中所有可用的音频端点。因此，我修改了他的示例程序，使其每5毫秒执行一次，并且只针对默认的渲染端点，在Windows7上偶尔也会出现同样的崩溃。

以下是示例的精简版本，在播放设备之间切换时有时会导致崩溃。我通常在设备之间来回切换的大约2分钟内就会崩溃。YMMV。

#include <windows.h>
#include <atlbase.h>
#include <stdio.h>
#include <mmdeviceapi.h>
#include <audiopolicy.h>
#include <endpointvolume.h>
#include <functiondiscoverykeys_devpkey.h>
#define LOG(format, ...) wprintf(format L"n", __VA_ARGS__)
class CoUninitializeOnExit {
public:
CoUninitializeOnExit() {}
~CoUninitializeOnExit() {
CoUninitialize();
}
};
class PropVariantClearOnExit {
public:
PropVariantClearOnExit(PROPVARIANT *p) : m_p(p) {}
~PropVariantClearOnExit() {
PropVariantClear(m_p);
}
private:
PROPVARIANT *m_p;
};
int _cdecl wmain() {
HRESULT hr = S_OK;
hr = CoInitialize(NULL);
if (FAILED(hr)) {
LOG(L"CoInitialize failed: hr = 0x%08x", hr);
return -__LINE__;
}
CoUninitializeOnExit cuoe;
while (1)
{
Sleep(5);
// get default device
CComPtr<IMMDeviceEnumerator> pMMDeviceEnumerator;
hr = pMMDeviceEnumerator.CoCreateInstance(__uuidof(MMDeviceEnumerator));
if (FAILED(hr)) {
LOG(L"CoCreateInstance(IMMDeviceEnumerator) failed: hr = 0x%08x", hr);
return -__LINE__;
}
CComPtr<IMMDevice> pMMDevice;
hr = pMMDeviceEnumerator->GetDefaultAudioEndpoint(eRender, eConsole, &pMMDevice);
if (FAILED(hr)) {
LOG(L"IMMDeviceEnumerator::GetDefaultAudioEndpoint failed: hr = 0x%08x", hr);
return -__LINE__;
}
// get the name of the endpoint
CComPtr<IPropertyStore> pPropertyStore;
hr = pMMDevice->OpenPropertyStore(STGM_READ, &pPropertyStore);
if (FAILED(hr)) {
LOG(L"IMMDevice::OpenPropertyStore failed: hr = 0x%08x", hr);
return -__LINE__;
}
PROPVARIANT v; PropVariantInit(&v);
PropVariantClearOnExit pvcoe(&v);
hr = pPropertyStore->GetValue(PKEY_Device_FriendlyName, &v);
if (FAILED(hr)) {
LOG(L"IPropertyStore::GetValue(PKEY_Device_FriendlyName) failed: hr = 0x%08x", hr);
return -__LINE__;
}
if (VT_LPWSTR != v.vt) {
LOG(L"PKEY_Device_FriendlyName has unexpected vartype %u", v.vt);
return -__LINE__;
}
LOG(L"Selected playback device: %sn", v.pwszVal);
// get a session enumerator
CComPtr<IAudioSessionManager2> pAudioSessionManager2;
hr = pMMDevice->Activate(
__uuidof(IAudioSessionManager2),
CLSCTX_ALL,
nullptr,
reinterpret_cast<void **>(&pAudioSessionManager2)
);
if (FAILED(hr)) {
LOG(L"IMMDevice::Activate(IAudioSessionManager2) failed: hr = 0x%08x", hr);
return -__LINE__;
}
CComPtr<IAudioSessionEnumerator> pAudioSessionEnumerator;
hr = pAudioSessionManager2->GetSessionEnumerator(&pAudioSessionEnumerator);
if (FAILED(hr)) {
LOG(L"IAudioSessionManager2::GetSessionEnumerator() failed: hr = 0x%08x", hr);
return -__LINE__;
}
// iterate over all the sessions
int count = 0;
hr = pAudioSessionEnumerator->GetCount(&count);
if (FAILED(hr)) {
LOG(L"IAudioSessionEnumerator::GetCount() failed: hr = 0x%08x", hr);
return -__LINE__;
}
for (int session = 0; session < count; session++) {
// get the session control
CComPtr<IAudioSessionControl> pAudioSessionControl;
hr = pAudioSessionEnumerator->GetSession(session, &pAudioSessionControl);
if (FAILED(hr)) {
LOG(L"IAudioSessionEnumerator::GetSession() failed: hr = 0x%08x", hr);
return -__LINE__;
}
AudioSessionState state;
hr = pAudioSessionControl->GetState(&state);
if (FAILED(hr)) {
LOG(L"IAudioSessionControl::GetState() failed: hr = 0x%08x", hr);
return -__LINE__;
}
CComPtr<IAudioSessionControl2> pAudioSessionControl2;
hr = pAudioSessionControl->QueryInterface(IID_PPV_ARGS(&pAudioSessionControl2));
if (FAILED(hr)) {
LOG(L"IAudioSessionControl::QueryInterface(IAudioSessionControl2) failed: hr = 0x%08x", hr);
return -__LINE__;
}
DWORD pid = 0;
hr = pAudioSessionControl2->GetProcessId(&pid);
if (FAILED(hr)) {
LOG(L"IAudioSessionControl2::GetProcessId() failed: hr = 0x%08x", hr);
return -__LINE__;
}
hr = pAudioSessionControl2->IsSystemSoundsSession();
if (FAILED(hr)) {
LOG(L"IAudioSessionControl2::IsSystemSoundsSession() failed: hr = 0x%08x", hr);
return -__LINE__;
}
bool bIsSystemSoundsSession = (S_OK == hr);
// get the current audio peak meter level for this session
CComPtr<IAudioMeterInformation> pAudioMeterInformation;
hr = pAudioSessionControl->QueryInterface(IID_PPV_ARGS(&pAudioMeterInformation));
if (FAILED(hr)) {
LOG(L"IAudioSessionControl::QueryInterface(IAudioMeterInformation) failed: hr = 0x%08x", hr);
return -__LINE__;
}
float peak = 0.0f;
hr = pAudioMeterInformation->GetPeakValue(&peak);
if (FAILED(hr)) {
LOG(L"IAudioMeterInformation::GetPeakValue() failed: hr = 0x%08x", hr);
return -__LINE__;
}
LOG(
L"    Session #%dn"
L"        State: %dn"
L"        Peak value: %gn"
L"        Process ID: %un"
L"        System sounds session: %s",
session,
state,
peak,
pid,
(bIsSystemSoundsSession ? L"yes" : L"no")
);
} // session
} // while
return 0;
}

以下是崩溃转储分析的一个实例：https://pastebin.com/tvRV8ukY.
这是核心音频API的Windows7实现的问题，还是我做错了什么？谢谢

Answer 1

我最终通过电子邮件联系了Matthew van Eerde，他说这看起来确实是Windows 7上Core Audio API的竞争条件，我最好的选择是向Microsoft提交支持请求
谢谢你的帮助，马修！