Andrew MacIntyre wrote:
>> Trevor Haba wrote:
>>> I'm looking for a way to use python to change the volume on windows.
>>> After some googling the best I could come up with was this script I
>>> got from a relatively ancient entry on this mailing list (I think it
>>> was from 2005 or something). I'm using windows 7, and I would like it
>>> to work on windows 8 if possible, though its not necessary. I don't
>>> need to support any previous versions of windows.
> To which Tim Roberts replied:
>> Alas, the news is not good.
> I think that comtypes (https://pypi.python.org/pypi/comtypes) can deal with
> early binding interfaces?
You are quite right, and the attached script does it. NOTE! that I have
not correctly defined all of the IMM interfaces for the general case;
I've only created enough of them to make this particular example work.
On my Win 7 machine, this is able to fetch the default endpoint, display
the volume range (from -65.25 to 0 in steps of 0.75) and change the setting.
I'm glad you brought this up. I've never played with comtypes before,
and this was a revealing exercise.
--
Tim Roberts, t...@probo.com
Providenza & Boekelheide, Inc.
import win32com
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(-20.0, None)
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