Problem trying to play noise through WASAPI

johnglen244 (34)
I am trying to play noise through the default speaker on my system using WASAPI, but I can not get it to work.

Here is the code that deals with the system:
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#include <InitGuid.h>
#include <iostream>
#include <Windows.h>
#include <dshow.h>
#include <Mmdeviceapi.h>
#include <Functiondiscoverykeys_devpkey.h>
#include <Audiopolicy.h>
#include <Audioclient.h>
#include "Noise_Gen.h"

#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_IAudioRenderClient = __uuidof(IAudioRenderClient);

HRESULT PlayAudioStream(Noise_Gen* pMySource) {
	HRESULT hr;
	REFERENCE_TIME hnsRequestedDuration = REFTIMES_PER_SEC;
	REFERENCE_TIME hnsActualDuration;
	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;
	IPropertyStore* pPropertyStore = NULL;
	PROPVARIANT name;

	hr = CoCreateInstance(CLSID_MMDeviceEnumerator, NULL,
						  CLSCTX_ALL, IID_IMMDeviceEnumerator,
						  (void**) &pEnumerator);
	EXIT_ON_ERROR(hr);
	hr = pEnumerator->GetDefaultAudioEndpoint(
		eRender, eConsole, &pDevice);

	hr = pDevice->OpenPropertyStore(STGM_READ, &pPropertyStore);
	PropVariantInit(&name);
	hr = pPropertyStore->GetValue(PKEY_Device_FriendlyName, &name);
	printf("%S", name.pwszVal);
	printf("\n");
	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);
	hr = pMySource->SetFormat(pwfx);
	EXIT_ON_ERROR(hr);
	hr = pAudioClient->GetBufferSize(&bufferFrameCount);
	EXIT_ON_ERROR(hr);
	hr = pAudioClient->GetService(IID_IAudioRenderClient,
								  (void**) &pRenderClient);
	EXIT_ON_ERROR(hr);
	hr = pRenderClient->GetBuffer(bufferFrameCount, &pData);
	EXIT_ON_ERROR(hr);
	hr = pMySource->LoadData(bufferFrameCount, pData, &flags);
	EXIT_ON_ERROR(hr);
	hr = pRenderClient->ReleaseBuffer(bufferFrameCount, flags);
	EXIT_ON_ERROR(hr);
	hnsActualDuration = (double) REFTIMES_PER_SEC * bufferFrameCount / pwfx->nSamplesPerSec;
	hr = pAudioClient->Start();  // Start playing.
	EXIT_ON_ERROR(hr);
	while(flags != AUDCLNT_BUFFERFLAGS_SILENT) {
		Sleep((DWORD) (hnsActualDuration / REFTIMES_PER_MILLISEC / 2));
		hr = pAudioClient->GetCurrentPadding(&numFramesPadding);
		EXIT_ON_ERROR(hr);
		numFramesAvailable = bufferFrameCount - numFramesPadding;
		hr = pRenderClient->GetBuffer(numFramesAvailable, &pData);
		EXIT_ON_ERROR(hr);
		hr = pMySource->LoadData(numFramesAvailable, pData, &flags);
		EXIT_ON_ERROR(hr);
		hr = pRenderClient->ReleaseBuffer(numFramesAvailable, flags);
		EXIT_ON_ERROR(hr);
	}
	Sleep((DWORD) (hnsActualDuration / REFTIMES_PER_MILLISEC / 2));
	hr = pAudioClient->Stop();  // Stop playing.
	EXIT_ON_ERROR(hr);
Exit:
	CoTaskMemFree(pwfx);
	SAFE_RELEASE(pEnumerator);
	SAFE_RELEASE(pDevice);
	SAFE_RELEASE(pAudioClient);
	SAFE_RELEASE(pRenderClient);
	return hr;
}

int main() {
	HRESULT hr = CoInitialize(nullptr);
	if(FAILED(hr)) { return hr; }
	Noise_Gen* ng = new Noise_Gen;
	PlayAudioStream(ng);
	CoUninitialize();
}


Here is the header and source used to generate the noise and write it to the buffer provided by the system's default audio endpoint.

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#pragma once

#include <functional>
#include <random>

template <typename T>
class Random {
public:
	Random(T low, T high) :function(std::bind(std::uniform_real_distribution<>(low, high), std::default_random_engine())) {}

	T operator()() { return function(); }

private:
	std::function<T()> function;
};

class Noise_Gen {

public:

	Noise_Gen() : rd(NULL) {};

	~Noise_Gen() {
		if(rd != NULL) {
			delete rd;
		}
	};

	HRESULT SetFormat(WAVEFORMATEX*);

	HRESULT LoadData(UINT32 bufferFrameCount, BYTE* pData, DWORD* flags);

private:
	void* rd;

	WORD nChannels;
	DWORD nSamplesPerSec;
	DWORD nAvgBytesPerSec;
	WORD nByteAlign;
	WORD wBitsPerSample;

	WORD wValidBitsPerSample;
	WORD wSamplesPerBlock;
	DWORD dwChannelMask;
};


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#include <Audiopolicy.h>
#include <Audioclient.h>
#include "Noise_Gen.h"

HRESULT Noise_Gen::SetFormat(WAVEFORMATEX* format) {
	nChannels = format->nChannels;
	nSamplesPerSec = format->nSamplesPerSec;
	nAvgBytesPerSec = format->nAvgBytesPerSec;
	nByteAlign = format->nBlockAlign;
	wBitsPerSample = format->wBitsPerSample;
	double amplitude = std::pow(2.0, wBitsPerSample) - 1;
	switch(wBitsPerSample / 8) {
	case(1):
		rd = new Random<unsigned __int8>(0.0, amplitude);
		break;
	case(2): 
		rd = new Random<unsigned __int16>(0.0, amplitude);
		break;
	case(3):
		rd = new Random<unsigned __int32>(0.0, amplitude);
		break;
	case(4): 
		rd = new Random<unsigned __int32>(0.0, amplitude);
		break;
	case(5): 
		rd = new Random<unsigned __int64>(0.0, amplitude);
		break;
	case(6):
		rd = new Random<unsigned __int64>(0.0, amplitude);
		break;
	case(7): 
		rd = new Random<unsigned __int64>(0.0, amplitude);
		break;
	case(8):
		rd = new Random<unsigned __int64>(0.0, amplitude);
		break;
	default:
		return E_NOTIMPL;
	}
	WORD  wFormatTag = format->wFormatTag;
	if(wFormatTag == WAVE_FORMAT_EXTENSIBLE) {
		WAVEFORMATEXTENSIBLE* pWFE = reinterpret_cast<WAVEFORMATEXTENSIBLE*>(format);
		wValidBitsPerSample = pWFE->Samples.wValidBitsPerSample;
		wSamplesPerBlock = pWFE->Samples.wSamplesPerBlock;
		dwChannelMask = pWFE->dwChannelMask;
	}
	return S_OK;
}

HRESULT Noise_Gen::LoadData(UINT32 bufferFrameCount, BYTE* pData, DWORD* flags) {
	for(UINT32 i = 0; i < nChannels *bufferFrameCount; i++) {
		switch(wBitsPerSample / 8) {
		case(1):
			pData[i] = (((Random<unsigned __int8>*)rd)->operator()());
			break;
		case(2):{
			unsigned __int16* pData2 = (unsigned __int16*) pData;
			pData2[i] = (((Random<unsigned __int16>*)rd)->operator()());
			break;
		}
		case(3): {
			__int32 data = ((Random<unsigned __int32>*)rd)->operator()();
			unsigned char* cp = (unsigned char*) (data);
			pData[(3 * i)] = cp[0];
			pData[1 + (3 * i)] = cp[1];
			pData[2 + (3 * i)] = cp[2];
			break;
		}
		case(4):{
			unsigned __int32* pData2 = (unsigned __int32*) pData;
			pData2[i] = (((Random<unsigned __int32>*)rd)->operator()());
			break;
		}
		case(5): {
			__int64 data = ((Random<unsigned __int64>*)rd)->operator()();
			unsigned char* cp = (unsigned char*) data;
			pData[(5 * i)] = cp[0];
			pData[1 + (5 * i)] = cp[1];
			pData[2 + (5 * i)] = cp[2];
			pData[3 + (5 * i)] = cp[3];
			pData[4 + (5 * i)] = cp[4];
			break;
		}
		case(6): {
			__int64 data = ((Random<unsigned __int64>*)rd)->operator()();
			unsigned char* cp = (unsigned char*) data;
			pData[(6 * i)] = cp[0];
			pData[1 + (6 * i)] = cp[1];
			pData[2 + (6 * i)] = cp[2];
			pData[3 + (6 * i)] = cp[3];
			pData[4 + (6 * i)] = cp[4];
			pData[5 + (6 * i)] = cp[5];
			break;
		}
		case(7): {
			__int64 data = ((Random<unsigned __int64>*)rd)->operator()();
			unsigned char* cp = (unsigned char*) data;
			pData[(7 * i)] = cp[0];
			pData[1 + (7 * i)] = cp[1];
			pData[2 + (7 * i)] = cp[2];
			pData[3 + (7 * i)] = cp[3];
			pData[4 + (7 * i)] = cp[4];
			pData[5 + (7 * i)] = cp[5];
			pData[6 + (7 * i)] = cp[6];
			break;
		}
		case(8): {
			unsigned __int64* pData2 = (unsigned __int64*) pData;
			pData2[i] = (((Random<unsigned __int64>*)rd)->operator()());
			break;
		}
		default:
			// For stopping playback
			(*flags) = AUDCLNT_BUFFERFLAGS_SILENT;
			return E_NOTIMPL;
		}
	}
	return S_OK;
}


I have tried unsigned and signed values. I have verified the speaker's buffer is being written to both by writing it's name to cmd, and seeing my app in the volume mixer. I have also debugged and see that the values being generated are indeed being written to pData. The volume mixer does not show sound being played though.

What is the error?
johnglen244 (34)
I had to check the format subtype. It was IEEE_FLOAT, so I had to use float values from -1 to 1.
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