C++ IAudioClient::GetBufferSize方法代码示例

    BlankAudioPlayback(CTSTR lpDevice)
    {
        const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
        const IID IID_IMMDeviceEnumerator    = __uuidof(IMMDeviceEnumerator);
        const IID IID_IAudioClient           = __uuidof(IAudioClient);
        const IID IID_IAudioRenderClient     = __uuidof(IAudioRenderClient);

        HRESULT err;
        err = CoCreateInstance(CLSID_MMDeviceEnumerator, NULL, CLSCTX_ALL, IID_IMMDeviceEnumerator, (void**)&mmEnumerator);
        if(FAILED(err))
            CrashError(TEXT("Could not create IMMDeviceEnumerator: 0x%08lx"), err);

        if (scmpi(lpDevice, TEXT("Default")) == 0)
            err = mmEnumerator->GetDefaultAudioEndpoint(eRender, eConsole, &mmDevice);
        else
            err = mmEnumerator->GetDevice(lpDevice, &mmDevice);
        if(FAILED(err))
            CrashError(TEXT("Could not create IMMDevice"));

        err = mmDevice->Activate(IID_IAudioClient, CLSCTX_ALL, NULL, (void**)&mmClient);
        if(FAILED(err))
            CrashError(TEXT("Could not create IAudioClient"));

        WAVEFORMATEX *pwfx;
        err = mmClient->GetMixFormat(&pwfx);
        if(FAILED(err))
            CrashError(TEXT("Could not get mix format from audio client"));

        UINT inputBlockSize = pwfx->nBlockAlign;

        err = mmClient->Initialize(AUDCLNT_SHAREMODE_SHARED, 0, ConvertMSTo100NanoSec(1000), 0, pwfx, NULL);
        if(FAILED(err))
            CrashError(TEXT("Could not initialize audio client, error = %08lX"), err);

        err = mmClient->GetService(IID_IAudioRenderClient, (void**)&mmRender);
        if(FAILED(err))
            CrashError(TEXT("Could not get audio render client"));

        //----------------------------------------------------------------

        UINT bufferFrameCount;
        err = mmClient->GetBufferSize(&bufferFrameCount);
        if(FAILED(err))
            CrashError(TEXT("Could not get audio buffer size"));

        BYTE *lpData;
        err = mmRender->GetBuffer(bufferFrameCount, &lpData);
        if(FAILED(err))
            CrashError(TEXT("Could not get audio buffer"));

        zero(lpData, bufferFrameCount*inputBlockSize);

        mmRender->ReleaseBuffer(bufferFrameCount, 0);//AUDCLNT_BUFFERFLAGS_SILENT); //probably better if it doesn't know

        if(FAILED(mmClient->Start()))
            CrashError(TEXT("Could not start audio source"));
    }

HRESULT __stdcall getbuffersize_patch(IAudioClient* this_, UINT32* pNumBufferFrames)
{
    IAudioClient* proxy = get_duplicate(this_)->proxy;
    DWORD_PTR* old_vftptr = swap_vtable(this_);
    HRESULT hr = proxy->GetBufferSize(pNumBufferFrames);
    ((DWORD_PTR**)this_)[0] = old_vftptr;
    for(iaudioclient_duplicate* next = get_duplicate(this_)->next; next != NULL; next = next->next)
    {
        UINT32 buf;
        HRESULT hr = next->proxy->GetBufferSize(&buf);
        assert(buf >= *pNumBufferFrames);
    }

    return hr;
}

//
//  Initialize WASAPI in event driven mode, associate the audio client with our samples ready event handle, retrieve 
//  a capture client for the transport, create the capture thread and start the audio engine.
//
bool CWASAPICapture::InitializeAudioEngine()
{
    HRESULT hr = _AudioClient->Initialize(AUDCLNT_SHAREMODE_SHARED, AUDCLNT_STREAMFLAGS_NOPERSIST, _EngineLatencyInMS*10000, 0, MixFormat(), NULL);
    PersistentAssert(SUCCEEDED(hr), "_AudioClient->Initialize failed");
    
    //
    //  Retrieve the buffer size for the audio client.
    //
    hr = _AudioClient->GetBufferSize(&_BufferSize);
    PersistentAssert(SUCCEEDED(hr), "_AudioClient->GetBufferSize failed");

    hr = _AudioClient->GetService(IID_PPV_ARGS(&_CaptureClient));
    PersistentAssert(SUCCEEDED(hr), "_AudioClient->GetService failed");

    return true;
}

void PlayAudio()
{
	REFERENCE_TIME hnsRequestedDuration = REFTIMES_PER_SEC;	// microseconds, so this is 1 seconds
	REFERENCE_TIME hnsActualDuration;

	HRESULT hr;

	IMMDeviceEnumerator *pEnumerator = NULL;
	IMMDevice *pDevice = NULL;
	IAudioClient *pAudioClient = NULL;
	IAudioRenderClient *pRenderClient = NULL;
	WAVEFORMATEX *pwfx = NULL;
	UINT32 bufferFrameCount;
	UINT32 numFramesAvailable;
	UINT32 numFramesPadding;
	BYTE *pData;
	DWORD flags = 0;


	hr = CoCreateInstance(CLSID_MMDeviceEnumerator, NULL, CLSCTX_ALL, IID_IMMDeviceEnumerator, (void**)&pEnumerator);
	EXIT_ON_ERROR(hr);

	hr = pEnumerator->GetDefaultAudioEndpoint(
		eRender, 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 actual size of the allocated buffer.
    hr = pAudioClient->GetBufferSize(&bufferFrameCount);
	EXIT_ON_ERROR(hr);

    hr = pAudioClient->GetService(
                         IID_IAudioRenderClient,
                         (void**)&pRenderClient);
	EXIT_ON_ERROR(hr);

    // Grab the entire buffer for the initial fill operation.
    hr = pRenderClient->GetBuffer(bufferFrameCount, &pData);
	EXIT_ON_ERROR(hr);

	// load initial data
	hr = LoadAudioBuffer(bufferFrameCount, pData, pwfx, &flags);
	EXIT_ON_ERROR(hr);

	hr = pRenderClient->ReleaseBuffer(bufferFrameCount, flags);
	EXIT_ON_ERROR(hr);

	// Calculate the actual duration of the allocated buffer.
    hnsActualDuration = (REFERENCE_TIME)((double)REFTIMES_PER_SEC * bufferFrameCount / pwfx->nSamplesPerSec);

    hr = pAudioClient->Start();  // Start playing.
	EXIT_ON_ERROR(hr);

    // Each loop fills about half of the shared buffer.
	while (flags != AUDCLNT_BUFFERFLAGS_SILENT)
	{
		        // Sleep for half the buffer duration.
        Sleep((DWORD)(hnsActualDuration/REFTIMES_PER_MILLISEC/2));

        // See how much buffer space is available.
        hr = pAudioClient->GetCurrentPadding(&numFramesPadding);
        EXIT_ON_ERROR(hr)

        numFramesAvailable = bufferFrameCount - numFramesPadding;

        // Grab all the available space in the shared buffer.
        hr = pRenderClient->GetBuffer(numFramesAvailable, &pData);
        EXIT_ON_ERROR(hr)

        // Get next 1/2-second of data from the audio source.
		hr = LoadAudioBuffer(numFramesAvailable, pData, pwfx, &flags);
        EXIT_ON_ERROR(hr)

        hr = pRenderClient->ReleaseBuffer(numFramesAvailable, flags);
        EXIT_ON_ERROR(hr)
    }

    // Wait for last data in buffer to play before stopping.
    Sleep((DWORD)(hnsActualDuration/REFTIMES_PER_MILLISEC/2));

    hr = pAudioClient->Stop();  // Stop playing.
	EXIT_ON_ERROR(hr);


//.........这里部分代码省略.........

//.........这里部分代码省略.........
    // create a periodic waitable timer
    HANDLE hWakeUp = CreateWaitableTimer(NULL, FALSE, NULL);
    if (NULL == hWakeUp) {
        DWORD dwErr = GetLastError();
        printf("CreateWaitableTimer failed: last error = %u\n", dwErr);
        CoTaskMemFree(pwfx);
        pAudioClient->Release();
        return HRESULT_FROM_WIN32(dwErr);
    }

    UINT32 nBlockAlign = pwfx->nBlockAlign;
    UINT32 nBufferSize;
    *pnFrames = 0;

    // call IAudioClient::Initialize
    // note that AUDCLNT_STREAMFLAGS_LOOPBACK and AUDCLNT_STREAMFLAGS_EVENTCALLBACK
    // do not work together...
    // the "data ready" event never gets set
    // so we're going to do a timer-driven loop
    hr = pAudioClient->Initialize(
        AUDCLNT_SHAREMODE_SHARED,
        AUDCLNT_STREAMFLAGS_LOOPBACK,
        0, 0, pwfx, 0
    );
    if (FAILED(hr)) {
        printf("IAudioClient::Initialize failed: hr = 0x%08x\n", hr);
        CloseHandle(hWakeUp);
        pAudioClient->Release();
        return hr;
    }
    CoTaskMemFree(pwfx);

    // Get the buffer size
    hr = pAudioClient->GetBufferSize(&nBufferSize);
    if (FAILED(hr)) {
        printf("IAudioClient::GetBufferSize failed: hr = 0x%08x\n", hr);
        CloseHandle(hWakeUp);
        pAudioClient->Release();
        return hr;
    }

    // Configure the server.  The buffer size returned is in frames
    // so assume stereo, 16 bits per sample to convert from frames to bytes
    server.configure(
        bMono,
        iSampleRateDivisor,
        nBufferSize * 2 * 2);

    // activate an IAudioCaptureClient
    IAudioCaptureClient *pAudioCaptureClient;
    hr = pAudioClient->GetService(
        __uuidof(IAudioCaptureClient),
        (void**)&pAudioCaptureClient
    );
    if (FAILED(hr)) {
        printf("IAudioClient::GetService(IAudioCaptureClient) failed: hr 0x%08x\n", hr);
        CloseHandle(hWakeUp);
        pAudioClient->Release();
        return hr;
    }
    
    // register with MMCSS
    DWORD nTaskIndex = 0;
    HANDLE hTask = AvSetMmThreadCharacteristics(L"Capture", &nTaskIndex);
    if (NULL == hTask) {
        DWORD dwErr = GetLastError();