Core Audio API控制windows音量 {#core-audio-api控制windows音量}

开发环境 {#开发环境}

-VS 2019
-windows 10 企业版 2016 长期服务版
-其他环境没有测试过

示例代码： {#示例代码}

test.h {#testh}

#pragma once
#include "SystemVolume.h"
#include <iostream>
#ifndef SRC_DEMO_H
#define SRC_DEMO_H
extern "C"
{
} #endif

test.cpp {#testcpp}

#include "test.h"
using namespace std;
using namespace SystemConf;
int main() {
SystemVolume systemVolume;
try {
	cout << "初始化 CoreAudioAPI " << endl;
	systemVolume.init();

	int volume = systemVolume.getVolume();
	cout << "获取当前音量为:" << volume << endl;

	cout << "设置音量为：80" << endl;
	systemVolume.setVolume(80);

	volume = systemVolume.getVolume();
	cout << "获取当前音量为:" << volume << endl;

	cout << "关闭服务" << endl;
	systemVolume.close();
}catch (string e) {
	cout << e << endl;
}catch (...) {
	cout << "出现异常，关闭服务 释放资源" << endl;
	systemVolume.close();
}
return 0;

}

SystemVolume.h {#systemvolumeh}

#pragma once
#ifndef SystemVolume_h
#include <windows.h>
#include <mmdeviceapi.h>
#include <endpointvolume.h>
#include <audioclient.h>
#define SystemVolume_h
namespace SystemConf {
class SystemVolume {
private:
	HRESULT hr;
	IMMDeviceEnumerator* pDeviceEnumerator = 0;
	IMMDevice* pDevice = 0;
	IAudioEndpointVolume* pAudioEndpointVolume = 0;
	IAudioClient* pAudioClient = 0;
public:
	/**初始化服务*/
	void init();
	/**关闭服务 释放资源*/
	void close();
	/**设置音量*/
	void setVolume(int volume);
	/**获取系统音量*/
	int getVolume();
	/**静音*/
	void Mute();
	/**解除静音*/
	void UnMute();
};

}
#endif

SystemVolume.cpp {#systemvolumecpp}

#include  "SystemVolume.h"
namespace SystemConf {
void SystemVolume::init() {
	hr = CoInitialize(0);
	hr = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL, CLSCTX_ALL, __uuidof(IMMDeviceEnumerator), (void**)&pDeviceEnumerator);
	if (FAILED(hr)) throw "InitException:pDeviceEnumerator is NULL;";
	hr = pDeviceEnumerator->GetDefaultAudioEndpoint(eRender, eMultimedia, &pDevice);
	if (FAILED(hr)) throw "InitException:pDevice is NULL";
	hr = pDevice->Activate(__uuidof(IAudioEndpointVolume), CLSCTX_ALL, NULL, (void**)&pAudioEndpointVolume);
	if (FAILED(hr)) throw "pDevice->Active";
	hr = pDevice->Activate(__uuidof(IAudioClient), CLSCTX_ALL, NULL, (void**)&pAudioClient);
	if (FAILED(hr)) throw "pDevice->Active";
}

void SystemVolume::close() {
	if (pAudioClient) pAudioClient->Release();
	if (pAudioEndpointVolume) pAudioEndpointVolume->Release();
	if (pDevice) pDevice->Release();
	if (pDeviceEnumerator) pDeviceEnumerator->Release();
	CoUninitialize();
}

void SystemVolume::setVolume(int volume) {
	float fVolume = volume / 100.0f;
	hr = pAudioEndpointVolume->SetMasterVolumeLevelScalar(fVolume, &GUID_NULL);
	if (FAILED(hr)) throw "SetMasterVolumeLevelScalar";
}

int SystemVolume::getVolume() {
	float volume;
	hr = pAudioEndpointVolume->GetMasterVolumeLevelScalar(&volume);
	if (FAILED(hr)) throw "getVolume() throw Exception";
	return (int)round(volume*100.0);
}

void SystemVolume::Mute() {
	hr = pAudioEndpointVolume->SetMute(TRUE, NULL);
	if (FAILED(hr)) throw "Mute() throw Exception";
}

void SystemVolume::UnMute() {
	hr = pAudioEndpointVolume->SetMute(FALSE, NULL);
	if (FAILED(hr)) throw "UnMute() throw Exception";
}

}