Implement RegisterAudioSessionNotification

[ColCh]

Make sure to give enough information to help debugging your issue.
Here are some hints:

currently, it stays unimplemented

link to docs: https://docs.microsoft.com/en-us/windows/win32/api/audiopolicy/nf-audiopolicy-iaudiosessioncontrol-registeraudiosessionnotification

pycaw/pycaw/pycaw.py

Lines 256 to 260 in f7bd1a9

	# HRESULT RegisterAudioSessionNotification(
	# [in] IAudioSessionEvents *NewNotifications);
	COMMETHOD([], HRESULT, 'NotImpl7'),
	# HRESULT UnregisterAudioSessionNotification(
	# [in] IAudioSessionEvents *NewNotifications);

Without this thing, it's impossible to listen upon audio session volume change :(

[AndreMiras]

Thanks for the report, maybe you could try your luck making a pull request implementing it 😉

[luluu9]

Hello, I'm trying to implement this functionality, but I've got some problems which I can't solve myself.
I've made IAudioSessionEvents class:

class IAudioSessionEvents(IUnknown): # https://docs.microsoft.com/en-us/windows/win32/coreaudio/audio-session-events
    _iid_ = GUID('{b1136c83-b6b5-4add-98a5-a2df8eedf6fc}')
    _methods_ = (
        # HRESULT OnSimpleVolumeChanged(
        # [in] float   NewVolume,
        # [in] BOOL    NewMute,
        # [in] LPCGUID EventContext);
        COMMETHOD([], HRESULT, 'OnSimpleVolumeChanged',
            (['in'], c_float, 'NewVolume'),
            (['in'], DWORD, 'NewMute'),
            (['in'], POINTER(GUID), 'EventContext')),
    )

and implemented Register and Unregister Audio Session Notification methods:

        # HRESULT RegisterAudioSessionNotification(
        # [in] IAudioSessionEvents *NewNotifications);
        COMMETHOD([], HRESULT, 'RegisterAudioSessionNotification',
                 (['in'], POINTER(IAudioSessionEvents), 'NewNotifications')),
        # HRESULT UnregisterAudioSessionNotification(
        # [in] IAudioSessionEvents *NewNotifications);
        COMMETHOD([], HRESULT, 'UnregisterAudioSessionNotification',
                 (['in'], POINTER(IAudioSessionEvents), 'NewNotifications')))

Taking as an example class AudioEndpointVolumeCallback(COMObject), I've created AudioSessionEvents:

class AudioSessionEvents(COMObject):
    _com_interfaces_ = [IAudioSessionEvents]

    def OnSimpleVolumeChanged(self, *args, **kwargs):
        print('OnSimpleVolumeChanged event')

I had thought everything was fine, but when I tried this code:

    callback = AudioSessionEvents()
    sessions = AudioUtilities.GetAllSessions()
    for session in sessions:
        session._ctl.RegisterAudioSessionNotification(callback)
        volume = session.SimpleAudioVolume
        print("volume.GetMute(): %s" % volume.GetMute())
        volume.SetMute(1, None)

there is no "OnSimpleVolumeChanged event" message.
Could someone guide me what is wrong?

[TurboAnonym]

Thats all what i could collect on this topic:

https://github.com/TurboAnonym/pycaw/tree/develop/IAudioSessionEvents

I made the nessesary changes in my pycaw.pycaw file in line 236 and 280

@luluu9

    COMMETHOD([], HRESULT, 'OnSimpleVolumeChanged',
        (['in'], c_float, 'NewVolume'),
        (['in'], DWORD, 'NewMute'),   <- shouldnt be that BOOL instead of DWORD?
        (['in'], POINTER(GUID), 'EventContext')),

[TurboAnonym]

@ColCh and @luluu9 good news everyone ;)
I successfully implemented it! (After a long long time xD)
#36

@luluu9 the problem was, that there where no dummy COMMETHODs like for OnIconPathChanged or the others ; )