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Posted 29 Jul 2011

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Change Master Volume in Visual C++

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4.69/5 (8 votes)
29 Jul 2011CPOL
How to set/change the master volume.

To change volume in Vista and Windows 7, use this code:

#include <mmdeviceapi.h>
#include <endpointvolume.h>

bool ChangeVolume(double nVolume,bool bScalar)

    bool decibels = false;
    bool scalar = false;
    double newVolume=nVolume;

    IMMDeviceEnumerator *deviceEnumerator = NULL;
    hr = CoCreateInstance(__uuidof(MMDeviceEnumerator), NULL, CLSCTX_INPROC_SERVER, 
                          __uuidof(IMMDeviceEnumerator), (LPVOID *)&deviceEnumerator);
    IMMDevice *defaultDevice = NULL;

    hr = deviceEnumerator->GetDefaultAudioEndpoint(eRender, eConsole, &defaultDevice);
    deviceEnumerator = NULL;

    IAudioEndpointVolume *endpointVolume = NULL;
    hr = defaultDevice->Activate(__uuidof(IAudioEndpointVolume), 
         CLSCTX_INPROC_SERVER, NULL, (LPVOID *)&endpointVolume);
    defaultDevice = NULL;

    // -------------------------
    float currentVolume = 0;
    //printf("Current volume in dB is: %f\n", currentVolume);

    hr = endpointVolume->GetMasterVolumeLevelScalar(&currentVolume);
    //CString strCur=L"";

    // printf("Current volume as a scalar is: %f\n", currentVolume);
    if (bScalar==false)
        hr = endpointVolume->SetMasterVolumeLevel((float)newVolume, NULL);
    else if (bScalar==true)
        hr = endpointVolume->SetMasterVolumeLevelScalar((float)newVolume, NULL);


    return FALSE;

The nVolume parameter must be between 0.0 and 1.0.

0.0 means mute and 1.0 means 100.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Comments and Discussions

QuestionSpecific app Pin
FreakMurderer13-Mar-23 10:14
FreakMurderer13-Mar-23 10:14 
QuestionIt is very nice. Pin
Jungryul Kim13-Feb-19 21:51
Jungryul Kim13-Feb-19 21:51 
PraiseExcellent Pin
Member 80819842-Mar-18 15:34
Member 80819842-Mar-18 15:34 
Questionunable to use this method. Pin
Member 116484109-Oct-15 1:38
Member 116484109-Oct-15 1:38 
GeneralMy vote of 5 Pin
wanggxii21-Aug-13 4:26
wanggxii21-Aug-13 4:26 
GeneralWin7 Volume control Pin
jimlundberg12-Jul-13 17:23
jimlundberg12-Jul-13 17:23 
GeneralMy vote of 5 Pin
ThatsAlok3-Jun-13 20:06
ThatsAlok3-Jun-13 20:06 
GeneralMy vote of 5 Pin
Shigetsugu23-Aug-12 20:18
Shigetsugu23-Aug-12 20:18 
QuestionYou should use attribution Pin
LonWolve7-Aug-12 17:49
LonWolve7-Aug-12 17:49 
GeneralMy vote of 1 Pin
LonWolve7-Aug-12 17:48
LonWolve7-Aug-12 17:48 
GeneralCurious... I haven't played with volume apps too much since ... Pin
Albert Holguin2-Aug-11 11:53
professionalAlbert Holguin2-Aug-11 11:53 

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