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Change Master Volume in Visual C++

, 29 Jul 2011 CPOL 41.1K 4
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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)
{
 
    HRESULT hr=NULL;
    bool decibels = false;
    bool scalar = false;
    double newVolume=nVolume;
 
    CoInitialize(NULL);
    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->Release();
    deviceEnumerator = NULL;
 
    IAudioEndpointVolume *endpointVolume = NULL;
    hr = defaultDevice->Activate(__uuidof(IAudioEndpointVolume), 
         CLSCTX_INPROC_SERVER, NULL, (LPVOID *)&endpointVolume);
    defaultDevice->Release();
    defaultDevice = NULL;
 
    // -------------------------
    float currentVolume = 0;
    endpointVolume->GetMasterVolumeLevel(&currentVolume);
    //printf("Current volume in dB is: %f\n", currentVolume);

    hr = endpointVolume->GetMasterVolumeLevelScalar(&currentVolume);
    //CString strCur=L"";
    //strCur.Format(L"%f",currentVolume);
    //AfxMessageBox(strCur);

    // 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);
    }
    endpointVolume->Release();
 
    CoUninitialize();
 
    return FALSE;
}

The nVolume parameter must be between 0.0 and 1.0.

0.0 means mute and 1.0 means 100.

License

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

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Comments and Discussions

 
GeneralMy vote of 5 Pin
wanggxii21-Aug-13 4:26
memberwanggxii21-Aug-13 4:26 
GeneralWin7 Volume control Pin
jimlundberg12-Jul-13 17:23
memberjimlundberg12-Jul-13 17:23 
GeneralMy vote of 5 Pin
ThatsAlok3-Jun-13 20:06
memberThatsAlok3-Jun-13 20:06 
GeneralMy vote of 5 Pin
Shigetsugu23-Aug-12 20:18
memberShigetsugu23-Aug-12 20:18 
コピペですぐ使えて、楽ちんでした。
Good!
QuestionYou should use attribution Pin
LonWolve7-Aug-12 17:49
memberLonWolve7-Aug-12 17:49 
GeneralMy vote of 1 Pin
LonWolve7-Aug-12 17:48
memberLonWolve7-Aug-12 17:48 
GeneralCurious... I haven't played with volume apps too much since ... Pin
Albert Holguin2-Aug-11 11:53
memberAlbert Holguin2-Aug-11 11:53 

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Article Copyright 2011 by Sayyed Mostafa Hashemi
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