公司做一个项目，需要把 windows 扬声器的声音捕捉下来，这个可以参考MSDN文档，上面有示例程序： Loopback Recording
Capturing a Stream
这程序并不完整，还需要做一些修改才行：
下面是我 调试通过的代码：
#include <Mmdeviceapi.h> #include <Audioclient.h> //----------------------------------------------------------- // 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); class MyAudioSink { public: //WAVEFORMATEX *pwfx = NULL; int SetFormat(WAVEFORMATEX *pwfx); int CopyData(char * pData,UINT32 numFramesAvailable,BOOL *pbDone); }; int MyAudioSink::SetFormat(WAVEFORMATEX *pwfx) { printf("wFormatTag is %x\n", pwfx->wFormatTag); printf("nChannels is %x\n", pwfx->nChannels); printf("nSamplesPerSec is %d\n", pwfx->nSamplesPerSec); printf("nAvgBytesPerSec is %d\n", pwfx->nAvgBytesPerSec); printf("wBitsPerSample is %d\n", pwfx->wBitsPerSample); return 0; } int MyAudioSink::CopyData(char * pData,UINT32 numFramesAvailable,BOOL *pbDone) { if(pData != NULL) fwrite(pData, numFramesAvailable ,1,fp); return 0; } /// pwfx->nSamplesPerSec = 44100; /// 不支持修改采样率， 看来只能等得到数据之后再 swr 转换了 BOOL AdjustFormatTo16Bits(WAVEFORMATEX *pwfx) { BOOL bRet(FALSE); if(pwfx->wFormatTag == WAVE_FORMAT_IEEE_FLOAT) { pwfx->wFormatTag = WAVE_FORMAT_PCM; pwfx->wBitsPerSample = 16; pwfx->nBlockAlign = pwfx->nChannels * pwfx->wBitsPerSample / 8; pwfx->nAvgBytesPerSec = pwfx->nBlockAlign * pwfx->nSamplesPerSec; bRet = TRUE; } else if(pwfx->wFormatTag == WAVE_FORMAT_EXTENSIBLE) { PWAVEFORMATEXTENSIBLE pEx = reinterpret_cast<PWAVEFORMATEXTENSIBLE>(pwfx); if (IsEqualGUID(KSDATAFORMAT_SUBTYPE_IEEE_FLOAT, pEx->SubFormat)) { pEx->SubFormat = KSDATAFORMAT_SUBTYPE_PCM; pEx->Samples.wValidBitsPerSample = 16; pwfx->wBitsPerSample = 16; pwfx->nBlockAlign = pwfx->nChannels * pwfx->wBitsPerSample / 8; pwfx->nAvgBytesPerSec = pwfx->nBlockAlign * pwfx->nSamplesPerSec; bRet = TRUE; } } return bRet; } HRESULT RecordAudioStream(MyAudioSink *pMySink) { HRESULT hr; REFERENCE_TIME hnsActualDuration; UINT32 bufferFrameCount; UINT32 numFramesAvailable; BYTE * pData; DWORD flags; REFERENCE_TIME hnsDefaultDevicePeriod(0); REFERENCE_TIME hnsRequestedDuration = REFTIMES_PER_SEC; IMMDeviceEnumerator* pEnumerator = NULL; IMMDevice * pDevice = NULL; IAudioClient * pAudioClient = NULL; IAudioCaptureClient * pCaptureClient = NULL; WAVEFORMATEX * pwfx = NULL; UINT32 packetLength = 0; BOOL bDone = FALSE; HANDLE hTimerWakeUp = NULL; hr = CoCreateInstance( CLSID_MMDeviceEnumerator, NULL,CLSCTX_ALL, IID_IMMDeviceEnumerator,(void**)&pEnumerator ); EXIT_ON_ERROR(hr) hr = pEnumerator->GetDefaultAudioEndpoint( eRender /*eCapture*/, eConsole, &pDevice ); EXIT_ON_ERROR(hr) hr = pDevice->Activate( IID_IAudioClient, CLSCTX_ALL, NULL, (void**)&pAudioClient); EXIT_ON_ERROR(hr) hr = pAudioClient->GetDevicePeriod(&hnsDefaultDevicePeriod, NULL); hr = pAudioClient->GetMixFormat(&pwfx); EXIT_ON_ERROR(hr) AdjustFormatTo16Bits(pwfx); hTimerWakeUp = CreateWaitableTimer(NULL, FALSE, NULL); hr = pAudioClient->Initialize( AUDCLNT_SHAREMODE_SHARED,AUDCLNT_STREAMFLAGS_LOOPBACK /*0*/ ,0 ,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) LARGE_INTEGER liFirstFire; liFirstFire.QuadPart = -hnsDefaultDevicePeriod / 2; // negative means relative time LONG lTimeBetweenFires = (LONG)hnsDefaultDevicePeriod / 2 / (10 * 1000); // convert to milliseconds BOOL bOK = SetWaitableTimer(hTimerWakeUp,&liFirstFire,lTimeBetweenFires,NULL, NULL, FALSE); // 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) HANDLE waitArray[1] = { /*htemp hEventStop,*/ hTimerWakeUp }; // Each loop fills about half of the shared buffer. while (bDone == FALSE) { // Sleep for half the buffer duration. //Sleep(hnsActualDuration/REFTIMES_PER_MILLISEC/2); //WaitForSingleObject(hTimerWakeUp,INFINITE); WaitForMultipleObjects(sizeof(waitArray)/sizeof(waitArray[0]), waitArray, FALSE, INFINITE); //WaitForMultipleObjects(sizeof(waitArray)/sizeof(waitArray[0]), waitArray, FALSE, INFINITE); 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((char *) pData, numFramesAvailable * pwfx->nBlockAlign, &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; } int _tmain(int argc, _TCHAR* argv[]) { fp = fopen("F://work//record.pcm","wb"); CoInitialize(NULL); MyAudioSink test; RecordAudioStream(&test); return 0; }留着以后使用
