pycaw.py fails at line 704: value = store.GetValue(pk)

[drp0]

I modified and adapted code from issues to produce a program to set / get any device volume.
I wrote it on my laptop, where it worked flawlessly. I tested it on my PC- with many audio devices- and it failed with the call to devicelist = MyAudioUtilities.GetAllDevices().
The error message clearly identifies a problem with line 704: value = store.GetValue(pk). This is the same error as detailed in this closed issue
I edited pycaw.py as recommended by Michael Farrell (micolous) in issue 15.
This work round allowed the program to reveal 67 audio devices and a bunch of other devices which had been causing issues with GetAllDevices().
It would be useful to make this change to the pycaw library!
I would recommend missing out the print statements in the except processing, unless people have nothing better to stare at.

Both machines have:
windows 11
Python 3.9.1
pycaw 20181226
comtypes 1.1.10
cmake 3.18.4.post1 (from python install)
enum34 1.1.10

My code:

from __future__ import print_function
from ctypes import POINTER, cast
import comtypes
from comtypes import CLSCTX_ALL
from pycaw.pycaw import AudioUtilities, IAudioEndpointVolume, CLSID_MMDeviceEnumerator, IMMDeviceEnumerator, EDataFlow, ERole

# audioVol3
# D.R.Patterson, 23/11/2021
# Get and set the volume of any audio device
# Using percentages.

# For the basis of this code: akaufman1, https://github.com/AndreMiras/pycaw/issues/8
# For pointing the way with SetMasterVolumeLevelScalar: Roy Joseph Argumido, https://github.com/AndreMiras/pycaw/issues/13

class MyAudioUtilities(AudioUtilities):
    @staticmethod
    def GetDevice(id=None, default=0):
        device_enumerator = comtypes.CoCreateInstance(
            CLSID_MMDeviceEnumerator,
            IMMDeviceEnumerator,
            comtypes.CLSCTX_INPROC_SERVER)
        if id is not None:
            thisDevice = device_enumerator.GetDevice(id)
        else:
            if default == 0:
                # output
                thisDevice = device_enumerator.GetDefaultAudioEndpoint(EDataFlow.eRender.value, ERole.eMultimedia.value)
            else:
                # input
                thisDevice = device_enumerator.GetDefaultAudioEndpoint(EDataFlow.eCapture.value, ERole.eMultimedia.value)
        return thisDevice


def main():
    mixer_output = None
    tmp = None
    devicelist = MyAudioUtilities.GetAllDevices()
    i = 0
    for device in devicelist:
        print(i, device)
        i += 1
    print(i, "Default Output")
    i += 1
    print(i, "Default Input")
    i += 1
    deviceSel = i
    
    while (deviceSel >= i) or (deviceSel < 0):
        print()
        search = input("Which device 0 to " + str(i-1) + ": ")
        deviceSel = int(search)

    
    if deviceSel < i-2:
        mixer_output = devicelist[int(search)]
        print(mixer_output)
        tmp = mixer_output.id
        devices = MyAudioUtilities.GetDevice(tmp)
    else:
        if deviceSel == i-2:
            print("Default Output")
            devices = MyAudioUtilities.GetDevice(tmp, 0)   # default output
        else:
            print("Default Input")
            devices = MyAudioUtilities.GetDevice(tmp, 1)   # default input
    print()
    interface = devices.Activate(IAudioEndpointVolume._iid_, CLSCTX_ALL, None)
    volume = cast(interface, POINTER(IAudioEndpointVolume))
    
    print("GetMute(): ", volume.GetMute())      # set using volume.SetMute(1, None)
    print("GetMasterVolumeLevelScalar(): %s" % int(0.5 + 100.0 * volume.GetMasterVolumeLevelScalar()))
    print("GetVolumeRange(): (%s, %s, %s)" % volume.GetVolumeRange())

    newLevel = input("Enter new level (Ctrl C to quit): ")

    intnewLevel = int(newLevel.replace('%', ''))
    if intnewLevel < 0:  intnewLevel = 0.0
    if intnewLevel > 100: intnewLevel = 100.0
    print("SetMasterVolumeLevelScalar", intnewLevel / 100.0)
    volume.SetMasterVolumeLevelScalar(intnewLevel / 100.0, None)
    print("GetMasterVolumeLevelScalar(): %s" % int(0.5 + 100.0 * volume.GetMasterVolumeLevelScalar()))

if __name__ == "__main__":
    try:
        while True:
            main()
            print()
    except KeyboardInterrupt:
        print()

pycaw.py solution from micolous:

           for j in range(propCount):
                pk = store.GetAt(j)
                try:
                    value = store.GetValue(pk)
                    v = value.GetValue()
                except:
                    # error getting property
                    print(f'Error getting device {id} property {pk}')
                    print('other properties:')
                    print(properties)
                    continue
                # TODO
                # PropVariantClear(byref(value))
                name = str(pk)
                properties[name] = v