How to identify the default audio device in Powershell? - powershell

Question

I am looking for a solution to get the default audio device via Powershell.
In best case, it could work via embedded C#-code to directly use IMMDeviceEnumerator::GetDefaultAudioEndpoint (see here IMMDeviceEnumertor).
But if it is easier to get this via RegKeys, then this is also OK.
I have seen a couple of code-snippets reading the keys from HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\MMDevices\Audio\Render or \Capture, but I still struggle to identify the DEFAULT device.
It seems, when I do modify the order of devices, then I can simply search for active devices (DeviceState=1) and then sort by the values "Level:0", "Level:1" and "Level:2", but the level-values are not available on a system, where the user has not modied the order manually. What is the sort-criteria in such case?
This is the code-snippet to solve it via RegKeys, but as mentioned - not working for all situations:
$regAudio = "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\MMDevices\Audio"
$nameId = "{b3f8fa53-0004-438e-9003-51a46e139bfc},6"
$classId = "{a45c254e-df1c-4efd-8020-67d146a850e0},2"
$driverDetails = "{83da6326-97a6-4088-9453-a1923f573b29},3"
function get-DefaultDevice($type) {
$activeDevices = foreach($key in Get-ChildItem "$regAudio\$type\") {
foreach($item in Get-ItemProperty $key.PsPath) {
if ($item.DeviceState -eq $activeState) {$item}
}
}
$defaultDevice = $activeDevices | Sort-Object -Property "Level:0","Level:1","Level:2" | select -last 1
$details = Get-ItemProperty "$($defaultDevice.PSPath)\Properties"
$name = "$($details.$classId) ($($details.$nameId))"
return #{
name = $name
driver = $details.$driverDetails
}
}
$OsRender = get-DefaultDevice "Render"
$OsCapture = get-DefaultDevice "Capture"
Is there any way to get this info "in a smart way" (without any external DLLs, of course)?

Answer 1

Finally I figured it out and I am happy to share the working code-snippet:
cls
Add-Type #'
[Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface IMMDevice {
int a(); int o();
int GetId([MarshalAs(UnmanagedType.LPWStr)] out string id);
}
[Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface IMMDeviceEnumerator {
int f();
int GetDefaultAudioEndpoint(int dataFlow, int role, out IMMDevice endpoint);
}
[ComImport, Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")] class MMDeviceEnumeratorComObject { }
public static string GetDefault (int direction) {
var enumerator = new MMDeviceEnumeratorComObject() as IMMDeviceEnumerator;
IMMDevice dev = null;
Marshal.ThrowExceptionForHR(enumerator.GetDefaultAudioEndpoint(direction, 1, out dev));
string id = null;
Marshal.ThrowExceptionForHR(dev.GetId(out id));
return id;
}
'# -name audio -Namespace system
function getFriendlyName($id) {
$reg = "HKLM:\SYSTEM\CurrentControlSet\Enum\SWD\MMDEVAPI\$id"
return (get-ItemProperty $reg).FriendlyName
}
$id0 = [audio]::GetDefault(0)
$id1 = [audio]::GetDefault(1)
write-host "Default Speaker: $(getFriendlyName $id0)"
write-host "Default Micro : $(getFriendlyName $id1)"
and in case you need a language-neutral international name of each device MMDEVICE-id and (optional) its driver then use this function:
# https://github.com/tpn/winsdk-10/blob/master/Include/10.0.16299.0/shared/devpkey.h
# https://github.com/EddieRingle/portaudio/blob/master/src/hostapi/wasapi/mingw-include/mmdeviceapi.h
$regId = "{b3f8fa53-0004-438e-9003-51a46e139bfc},2"
$regName = "{b3f8fa53-0004-438e-9003-51a46e139bfc},6"
$regFormFactor = "{1da5d803-d492-4edd-8c23-e0c0ffee7f0e},0"
# https://learn.microsoft.com/en-us/windows/win32/api/mmdeviceapi/ne-mmdeviceapi-endpointformfactor
$formFactor = #(
"RemoteNetworkDevice",
"Speakers",
"LineLevel",
"Headphones",
"Microphone",
"Headset",
"Handset",
"UnknownDigitalPassthrough",
"SPDIF",
"DigitalAudioDisplayDevice",
"UnknownFormFactor"
)
function getInternationalNameAndDriver($id) {
$guid = $id.Substring(17)
$subKey = #("Render","Capture")[[int]::Parse($id[5])]
$reg = "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\MMDevices\Audio\$subKey\$guid\Properties"
$details = get-ItemProperty $reg -ea 0
if ($details) {
$id = $details.$regId.subString(4)
$name = $details.$regName
$form = $formFactor[$details.$regFormFactor]
$hardware = get-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Enum\$id"
$regDrv = $hardware.Driver
$driver = Get-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Control\Class\$regDrv"
$drvName = $driver.DriverDesc
$drvVersion = $driver.DriverVersion
}
return "$form ($name), driver: $drvName $drvVersion"
}
this gives you an output like this:
Default Speaker: Speakers (Realtek Audio), driver: Realtek Audio 6.0.1.6127
Default Micro : Microphone (Logitech BRIO), driver: USB Audio Device 10.0.22000.653