Programmatically changing system-wide speaker balance on Windows 7

Question

How can I programmatically change system-wide speaker balance on Windows 7?

(I can only program in Python and AHK.)

Answer 1

Shortcut(created by @AndreMiras) --> use Pycaw , usage of Pycaw can be find here

Detailed way -- > First install python package Comtypes either by

1. using pip install comtypes

   or

2. download from https://pypi.python.org/pypi/comtypes and then extract the download folder. Find setup.py in extracted folder . Open cmd go to the path of setup.py and then run the command python setup.py install

Now just run the code.py file and you can adjust the volume by changing the first argument of function SetMasterVolumeLevel(-25, None) the first argument must be in between -65 to 0. I have tried this code in windows 8 hopefully it will work on windows 7.

See at the last lines of code to find the volume.SetMasterVolumeLevel(-25, None) and to adust the volume of PC

Code.py

from comtypes import *
import comtypes.client
from ctypes import POINTER
from ctypes.wintypes import DWORD, BOOL

MMDeviceApiLib = \
    GUID('{2FDAAFA3-7523-4F66-9957-9D5E7FE698F6}')
IID_IMMDevice = \
    GUID('{D666063F-1587-4E43-81F1-B948E807363F}')
IID_IMMDeviceEnumerator = \
    GUID('{A95664D2-9614-4F35-A746-DE8DB63617E6}')
CLSID_MMDeviceEnumerator = \
    GUID('{BCDE0395-E52F-467C-8E3D-C4579291692E}')
IID_IMMDeviceCollection = \
    GUID('{0BD7A1BE-7A1A-44DB-8397-CC5392387B5E}')
IID_IAudioEndpointVolume = \
    GUID('{5CDF2C82-841E-4546-9722-0CF74078229A}')

class IMMDeviceCollection(IUnknown):
    _iid_ = GUID('{0BD7A1BE-7A1A-44DB-8397-CC5392387B5E}')
    pass

class IAudioEndpointVolume(IUnknown):
    _iid_ = GUID('{5CDF2C82-841E-4546-9722-0CF74078229A}')
    _methods_ = [
        STDMETHOD(HRESULT, 'RegisterControlChangeNotify', []),
        STDMETHOD(HRESULT, 'UnregisterControlChangeNotify', []),
        STDMETHOD(HRESULT, 'GetChannelCount', []),
        COMMETHOD([], HRESULT, 'SetMasterVolumeLevel',
            (['in'], c_float, 'fLevelDB'),
            (['in'], POINTER(GUID), 'pguidEventContext')
        ),
        COMMETHOD([], HRESULT, 'SetMasterVolumeLevelScalar',
            (['in'], c_float, 'fLevelDB'),
            (['in'], POINTER(GUID), 'pguidEventContext')
        ),
        COMMETHOD([], HRESULT, 'GetMasterVolumeLevel',
            (['out','retval'], POINTER(c_float), 'pfLevelDB')
        ),
        COMMETHOD([], HRESULT, 'GetMasterVolumeLevelScalar',
            (['out','retval'], POINTER(c_float), 'pfLevelDB')
        ),
        COMMETHOD([], HRESULT, 'SetChannelVolumeLevel',
            (['in'], DWORD, 'nChannel'),
            (['in'], c_float, 'fLevelDB'),
            (['in'], POINTER(GUID), 'pguidEventContext')
        ),
        COMMETHOD([], HRESULT, 'SetChannelVolumeLevelScalar',
            (['in'], DWORD, 'nChannel'),
            (['in'], c_float, 'fLevelDB'),
            (['in'], POINTER(GUID), 'pguidEventContext')
        ),
        COMMETHOD([], HRESULT, 'GetChannelVolumeLevel',
            (['in'], DWORD, 'nChannel'),
            (['out','retval'], POINTER(c_float), 'pfLevelDB')
        ),
        COMMETHOD([], HRESULT, 'GetChannelVolumeLevelScalar',
            (['in'], DWORD, 'nChannel'),
            (['out','retval'], POINTER(c_float), 'pfLevelDB')
        ),
        COMMETHOD([], HRESULT, 'SetMute',
            (['in'], BOOL, 'bMute'),
            (['in'], POINTER(GUID), 'pguidEventContext')
        ),
        COMMETHOD([], HRESULT, 'GetMute',
            (['out','retval'], POINTER(BOOL), 'pbMute')
        ),
        COMMETHOD([], HRESULT, 'GetVolumeStepInfo',
            (['out','retval'], POINTER(c_float), 'pnStep'),
            (['out','retval'], POINTER(c_float), 'pnStepCount'),
        ),
        COMMETHOD([], HRESULT, 'VolumeStepUp',
            (['in'], POINTER(GUID), 'pguidEventContext')
        ),
        COMMETHOD([], HRESULT, 'VolumeStepDown',
            (['in'], POINTER(GUID), 'pguidEventContext')
        ),
        COMMETHOD([], HRESULT, 'QueryHardwareSupport',
            (['out','retval'], POINTER(DWORD), 'pdwHardwareSupportMask')
        ),
        COMMETHOD([], HRESULT, 'GetVolumeRange',
            (['out','retval'], POINTER(c_float), 'pfMin'),
            (['out','retval'], POINTER(c_float), 'pfMax'),
            (['out','retval'], POINTER(c_float), 'pfIncr')
        ),

    ]

class IMMDevice(IUnknown):
    _iid_ = GUID('{D666063F-1587-4E43-81F1-B948E807363F}')
    _methods_ = [
        COMMETHOD([], HRESULT, 'Activate',
            (['in'], POINTER(GUID), 'iid'),
            (['in'], DWORD, 'dwClsCtx'),
            (['in'], POINTER(DWORD), 'pActivationParans'),
            (['out','retval'], POINTER(POINTER(IAudioEndpointVolume)), 'ppInterface')
        ),
        STDMETHOD(HRESULT, 'OpenPropertyStore', []),
        STDMETHOD(HRESULT, 'GetId', []),
        STDMETHOD(HRESULT, 'GetState', [])
    ]
    pass

class IMMDeviceEnumerator(comtypes.IUnknown):
    _iid_ = GUID('{A95664D2-9614-4F35-A746-DE8DB63617E6}')

    _methods_ = [
        COMMETHOD([], HRESULT, 'EnumAudioEndpoints',
            (['in'], DWORD, 'dataFlow'),
            (['in'], DWORD, 'dwStateMask'),
            (['out','retval'], POINTER(POINTER(IMMDeviceCollection)), 'ppDevices')
        ),
        COMMETHOD([], HRESULT, 'GetDefaultAudioEndpoint',
            (['in'], DWORD, 'dataFlow'),
            (['in'], DWORD, 'role'),
            (['out','retval'], POINTER(POINTER(IMMDevice)), 'ppDevices')
        )
    ]





enumerator = comtypes.CoCreateInstance( 
    CLSID_MMDeviceEnumerator,
    IMMDeviceEnumerator,
    comtypes.CLSCTX_INPROC_SERVER
)

print enumerator
endpoint = enumerator.GetDefaultAudioEndpoint( 0, 1 )
print endpoint
volume = endpoint.Activate( IID_IAudioEndpointVolume, comtypes.CLSCTX_INPROC_SERVER, None )
print volume
print volume.GetMasterVolumeLevel()
print volume.GetVolumeRange()
#volume.SetMasterVolumeLevel(-65, None) uncomment for 0 volume
#volume.SetMasterVolumeLevel(-1, None) uncomment for full volume
volume.SetMasterVolumeLevel(-25, None) #Change the first argument for controlling the volume remember it should be -ve not less than -65