Windows系统常见API

最新推荐文章于 2024-10-11 22:12:45 发布

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最新推荐文章于 2024-10-11 22:12:45 发布

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分类专栏：系统

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Core Audio

MMDevice API （mmdeviceapi.h)

IMMDeviceEnumerator	枚举音频设备集（IMMDeviceCollection），获取默认设备，通过ID获取设备(IMMDevice)，注册通知，取消通知(IMMNotificationClient)
IMMDeviceCollection	音频设备集中数量，通过索引取出设备(IMMDevice)
IMMNotificationClient	IUnknow接口，继承实现IUnknow和设备状态改变、设备增加、设备删除、默认设备改变和设备属性改变通知接口
IMMDevice	激活设备、获取设备ID、获取设备状态和获取设备属性表
IMMEndpoint	获取设备eRender和eCapture（通过IMMDevice查询获取）

// IMMDeviceEnumerator
IMMDeviceEnumerator* pEnumerator = nullptr;
CoCreateInstance(__uuidof(MMDeviceEnumerator), nullptr, CLSCTX_ALL, __uuidof(IMMDeviceEnumerator), (void**)&pEnumerator);
// IMMDeviceCollection    - DEVICE_STATE_ACTIVE 激活状态
IMMDeviceCollection* pCollection = nullptr;
pEnumerator->EnumAudioEndpoints(eAll, DEVICE_STATEMASK_ALL, &pCollection);
pCollection->GetCount(&uDeviceCount);
pCollection->Item(i, &pEndpoint);
// IMMNotificationClient
IMMNotificationClient *pClient;
pEnumerator->RegisterEndpointNotificationCallback(pClient);
pEnumerator->UnregisterEndpointNotificationCallback(pClient);
// IMMDevice 依据id通过IMMDeviceEnumerator接口可获取 - 连过设备会在枚举有记录状态不一样
IMMDevice* pMMDevice = nullptr;
pEnumerator->GetDevice(wszID.c_str(), &pMMDevice);
pEnumerator->GetDevice(eCapture, eConsole, &pMMDevice);
pMMDevice->GetId(&pwszID);
pMMDevice->GetState(&dwState);
pMMDevice->OpenPropertyStore(STGM_READ, &pProps);
IAudioClient* pAudioClient;
pMMDevice->Activate(__uuidof(IAudioClient), CLSCTX_ALL, NULL, (void**)&pAudioClient);
// IMMEndpoint
IMMEndpoint* pMMEndpoint = nullptr;
pMMDevice->QueryInterface(__uuidof(IMMEndpoint), (void**)&pMMEndpoint);
pMMEndpoint->GetDataFlow(&emEDataFlow);

class CAudioDeviceWinMgr : public IMMNotificationClient
{
public:
    // IMMNotificationClient
    ULONG STDMETHODCALLTYPE AddRef();
    ULONG STDMETHODCALLTYPE Release();
    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, VOID** ppvInterface);
    HRESULT STDMETHODCALLTYPE OnDeviceStateChanged(LPCWSTR pwstrDeviceId,DWORD dwNewState);
    HRESULT STDMETHODCALLTYPE OnDeviceAdded(LPCWSTR pwstrDeviceId);
    HRESULT STDMETHODCALLTYPE OnDeviceRemoved(LPCWSTR pwstrDeviceId);
    HRESULT STDMETHODCALLTYPE OnDefaultDeviceChanged(EDataFlow flow,ERole role,LPCWSTR pwstrDefaultDeviceId);
    HRESULT STDMETHODCALLTYPE OnPropertyValueChanged(LPCWSTR pwstrDeviceId,const PROPERTYKEY key);
private:
    LONG  m_cRef = 0;
};

ULONG __stdcall CAudioDeviceWinMgr::AddRef()
{   return InterlockedIncrement(&m_cRef);   }
ULONG __stdcall CAudioDeviceWinMgr::Release()
{
    ULONG ulRef = InterlockedDecrement(&m_cRef);
    if (0 == ulRef) {  delete this; }
    return ulRef;
}
HRESULT __stdcall CAudioDeviceWinMgr::QueryInterface(REFIID riid, VOID** ppvInterface)
{
    if (IID_IUnknown == riid){
        AddRef();
        *ppvInterface = (IUnknown*)this;
    } else if (__uuidof(IMMNotificationClient) == riid) {
        AddRef();
        *ppvInterface = (IMMNotificationClient*)this;
    } else {
        *ppvInterface = NULL;
        return E_NOINTERFACE;
    }
    return S_OK;
}

WAS API

// IAudioClient
// 不设置事件通知可不加AUDCLNT_STREAMFLAGS_EVENTCALLBACK，不必调用SetEventHandle
// Initialize 第三个参数以100ns为单位，决定了GetBufferSize大小，而它以采样数为单位
HANDLE hSamplesReadyEvent = CreateEventEx(NULL, NULL, 0, EVENT_MODIFY_STATE | SYNCHRONIZE);
pAudioClient->GetMixFormat(&pWaveFormateEx);
pAudioClient->Initialize(AUDCLNT_SHAREMODE_SHARED, AUDCLNT_STREAMFLAGS_EVENTCALLBACK, 20000000, 0, pWaveFormateEx, NULL);
UINT32 bufferFrameCount;
m_pAudioClient->GetBufferSize(&bufferFrameCount);
pAudioClient->SetEventHandle(hSamplesReadyEvent );
IAudioCaptureClient* pCaptureClient;
pAudioClient->GetService(__uuidof(IAudioCaptureClient), (void**)&pCaptureClient);
pAudioClient->Start();
pAudioClient->Stop();
SetEvent(hSamplesReadyEvent);
CloseHandle(hSamplesReadyEvent);

// IAudioCaptureClient
// numFramesAvailable 是以采样数为单位，跟通道和采样位数无关
// 不用事件通知时可通过sleep一半buffersize的时间来进行
WaitForSingleObject(hSamplesReadyEvent, INFINITE);
pCaptureClient->GetNextPacketSize(&packetLength);
pCaptureClient->GetBuffer(&pData, &numFramesAvailable, &flags, &u64DevicePosition, &u64QPCPosition);
pCaptureClient->ReleaseBuffer(numFramesAvailable);

注意

windows com 从接口获取的结构体，字符串，都通过CoTaskMemFree 来释放内存

LPWSTR pwszID = nullptr;
pMMDevice->GetId(&pwszID);
if (pwszID) { CoTaskMemFree(pwszID); }
WAVEFORMATEX* pWaveFormateEx = nullptr;
pAudioClient->GetMixFormat(&pWaveFormateEx);
if (pWaveFormateEx) { CoTaskMemFree(pWaveFormateEx); }

windows 通用变量用法（有待完善）

IPropertyStore* pProps;
PROPVARIANT varName;
::PropVariantInit(&varName);
pProps->GetValue(PKEY_Device_FriendlyName, &varName);
::PropVariantClear(&varName);

附录

录制音频流渲染音频流