microsoft官网给出的录音demo

//-----------------------------------------------------------
// Record an audio stream from the default audio capture
// device. The RecordAudioStream function allocates a shared
// buffer big enough to hold one second of PCM audio data.
// The function uses this buffer to stream data from the
// capture device. The main loop runs every 1/2 second.
//-----------------------------------------------------------// REFERENCE_TIME time units per second and per millisecond
#define REFTIMES_PER_SEC  10000000
#define REFTIMES_PER_MILLISEC  10000#define EXIT_ON_ERROR(hres)  \if (FAILED(hres)) { goto Exit; }
#define SAFE_RELEASE(punk)  \if ((punk) != NULL)  \{ (punk)->Release(); (punk) = NULL; }const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);
const IID IID_IAudioClient = __uuidof(IAudioClient);
const IID IID_IAudioCaptureClient = __uuidof(IAudioCaptureClient);HRESULT RecordAudioStream(MyAudioSink *pMySink)
{HRESULT hr;REFERENCE_TIME hnsRequestedDuration = REFTIMES_PER_SEC;REFERENCE_TIME hnsActualDuration;UINT32 bufferFrameCount;UINT32 numFramesAvailable;IMMDeviceEnumerator *pEnumerator = NULL;IMMDevice *pDevice = NULL;IAudioClient *pAudioClient = NULL;IAudioCaptureClient *pCaptureClient = NULL;WAVEFORMATEX *pwfx = NULL;UINT32 packetLength = 0;BOOL bDone = FALSE;BYTE *pData;DWORD flags;hr = CoCreateInstance(CLSID_MMDeviceEnumerator, NULL,CLSCTX_ALL, IID_IMMDeviceEnumerator,(void**)&pEnumerator);EXIT_ON_ERROR(hr)hr = pEnumerator->GetDefaultAudioEndpoint(eCapture, eConsole, &pDevice);EXIT_ON_ERROR(hr)hr = pDevice->Activate(IID_IAudioClient, CLSCTX_ALL,NULL, (void**)&pAudioClient);EXIT_ON_ERROR(hr)hr = pAudioClient->GetMixFormat(&pwfx);EXIT_ON_ERROR(hr)hr = pAudioClient->Initialize(AUDCLNT_SHAREMODE_SHARED,0,hnsRequestedDuration,0,pwfx,NULL);EXIT_ON_ERROR(hr)// Get the size of the allocated buffer.hr = pAudioClient->GetBufferSize(&bufferFrameCount);EXIT_ON_ERROR(hr)hr = pAudioClient->GetService(IID_IAudioCaptureClient,(void**)&pCaptureClient);EXIT_ON_ERROR(hr)// Notify the audio sink which format to use.hr = pMySink->SetFormat(pwfx);EXIT_ON_ERROR(hr)// Calculate the actual duration of the allocated buffer.hnsActualDuration = (double)REFTIMES_PER_SEC *bufferFrameCount / pwfx->nSamplesPerSec;hr = pAudioClient->Start();  // Start recording.EXIT_ON_ERROR(hr)// Each loop fills about half of the shared buffer.while (bDone == FALSE){// Sleep for half the buffer duration.Sleep(hnsActualDuration/REFTIMES_PER_MILLISEC/2);hr = pCaptureClient->GetNextPacketSize(&packetLength);EXIT_ON_ERROR(hr)while (packetLength != 0){// Get the available data in the shared buffer.hr = pCaptureClient->GetBuffer(&pData,&numFramesAvailable,&flags, NULL, NULL);EXIT_ON_ERROR(hr)if (flags & AUDCLNT_BUFFERFLAGS_SILENT){pData = NULL;  // Tell CopyData to write silence.}// Copy the available capture data to the audio sink.hr = pMySink->CopyData(pData, numFramesAvailable, &bDone);EXIT_ON_ERROR(hr)hr = pCaptureClient->ReleaseBuffer(numFramesAvailable);EXIT_ON_ERROR(hr)hr = pCaptureClient->GetNextPacketSize(&packetLength);EXIT_ON_ERROR(hr)}}hr = pAudioClient->Stop();  // Stop recording.EXIT_ON_ERROR(hr)Exit:CoTaskMemFree(pwfx);SAFE_RELEASE(pEnumerator)SAFE_RELEASE(pDevice)SAFE_RELEASE(pAudioClient)SAFE_RELEASE(pCaptureClient)return hr;
}