IAudioSessionNotification，有人有工作代码吗?

2022-01-14 00:00:00 windows audio com windows-7 c++

现在我已经安装了 RC，我正在挑选一些我在 Windows 7 Beta 中搞砸的实验性代码.

I'm picking up some experimental code I was messing with in the Windows 7 Beta now that I've installed the RC.

基本上，我正在尝试获取 IAudioSessionManager2 &IAudioSessionNotification 一起工作以通知我的小应用程序创建的每个新音频会话.

Basically, I'm trying to get IAudioSessionManager2 & IAudioSessionNotification working together to inform my little app of every new audio session created.

AudioListener 中的关键代码(公共 IAudioSessionNotification):

Punchline code in AudioListener (public IAudioSessionNotification):

//This is mostly lifted from MSDN
HRESULT STDMETHODCALLTYPE AudioListener::QueryInterface(REFIID riid, void** ppvObject)
{
    if(riid == __uuidof(IUnknown))
    {
        *ppvObject = (IUnknown*)this;
        return S_OK;
    }

    if(riid == __uuidof(IAudioSessionNotification))
    {
        *ppvObject = (IAudioSessionNotification*)this;
        return S_OK;
    }

    *ppvObject = NULL;

    return E_NOINTERFACE;
}

//m_hwnd, and WM_SESSION_CREATED are set to good values
//WM_SESSION_CREATEd via RegisterWindowMessage(...)
HRESULT STDMETHODCALLTYPE AudioListener::OnSessionCreated(IAudioSessionControl *pSession)
{
    PostMessage(m_hwnd, WM_SESSION_CREATED, (WPARAM)pSession, 0);

    return S_OK;
}

注册我的监听器的代码:

Code registering my listener:

BOOL RegisterMonitor(HWND target)
{
    BOOL success = false;

    HRESULT res;
    IMMDevice* pDevice;
    IMMDeviceEnumerator* pEnumerator;

    SESSION_LISTENER = NULL;
    SESSION = NULL;

    res = CoInitialize(NULL);

    if(res != S_OK && res != S_FALSE)
        return false;

    SESSION_LISTENER = new AudioListener(target);

    res = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL, CLSCTX_ALL, __uuidof(IMMDeviceEnumerator), (void**)&pEnumerator);
    if(res != S_OK)  goto Exit;

    res = pEnumerator->GetDefaultAudioEndpoint(eRender, eMultimedia, &pDevice);
    if(res != S_OK)  goto Exit;

    res = pDevice->Activate(__uuidof(IAudioSessionManager2), CLSCTX_ALL, NULL, (void**)&SESSION);
    if(res != S_OK)  goto Exit;

    res = SESSION->RegisterSessionNotification(SESSION_LISTENER);
    if(res != S_OK)  goto Exit;

    success = true;

Exit:
    SAFE_RELEASE(pEnumerator);
    SAFE_RELEASE(pDevice);
    if(!success)
    {
        SAFE_RELEASE(SESSION_LISTENER);
        SAFE_RELEASE(SESSION);
    }

    return success;
}

RegisterMonitor(...) 返回 true，但从未收到任何通知.我一直在通过启动带有轻微音效的小应用程序并触发它们(Soltaire、Minesweeper 等)进行测试，确认它们在我期望看到通知时出现在 SndVol 中.

RegisterMonitor(...) returns true, but no notifications are ever received. I've been testing by launching little apps with minor sound effects and triggering them (Soltaire, Minesweeper, etc.), confirming that they show up in SndVol when I'm expecting to see a notification.

基本上，有没有人看到我做错了什么?

Basically, does anyone see what I'm doing wrong?

推荐答案

您在 RegisterMonitor 函数中发布了会话管理器.一旦您释放对会话管理器的最后一个引用，它就会被释放，您将不再收到会话通知.

You released the session manager in your RegisterMonitor function. Once you release the last reference to the session manager it is freed and you'll no longer receive session notifications.

保持会话管理器对象处于活动状态，它应该可以正常工作.

Keep the session manager object alive and it should work just fine.

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