How to get the name of application(s) currently playing audio with powershell using NAudio?

I'm trying to get the name of applications that are actively playing audio in Windows 11 using the NAudio library. I'm using the latest official precompiled NAudio.dll v.1.9 as I could not get it working with the latest nuget package 2.2.1. With this code I can get the playback devices info but the Audio Sessions are always empty.

Add-Type -Path "C:\NAudio.dll"
$devices = (New-Object -TypeName NAudio.CoreAudioApi.MMDeviceEnumerator).EnumerateAudioEndPoints([NAudio.CoreAudioApi.DataFlow]::Render, [NAudio.CoreAudioApi.DeviceState]::Active)
foreach ($device in $devices) {
    Write-Host "Device: $($device.FriendlyName)"
    $sessions = $device.AudioSessionManager2.Sessions
    Write-Host "Number of sessions: $($sessions.Count)"
    foreach ($session in $sessions) {
        Write-Host "Session: $($session.DisplayName)"
        Write-Host "Is Muted: $($session.SimpleAudioVolume.Mute)"
        Write-Host "Volume: $($session.SimpleAudioVolume.Volume)"
    }
}

Terminal output:

Device: Sound Blaster Z (Sound Blaster Z)
Number of sessions: 0

I did read the questions where people were able to get audio sessions using C# but I was hoping to be able to do the same in PowerShell.

Solution

The reason why downloading the latest package from Nuget didn't work for you is because the NAudio Package has a bunch of dependencies (including the NAudio.CoreAudioApi Namespace, where the MMDeviceEnumerator Class exists).

Specifically, the MMDeviceEnumerator class exists in NAudio.Wasapi Pacakage:

PS ..\pwsh> [NAudio.CoreAudioApi.MMDeviceEnumerator].Assembly

Version    Name               PublicKeyToken    Target Culture
-------    ----               --------------    ------ -------
2.2.1.0    NAudio.Wasapi      e279aa5131008a41  MSIL   neutral

Ideally, Install-Package should be able to handle dependencies for you (unsure on this, my experience with this cmdlet is really bad - see other option using the dotnet CLI below):

Install-Package NAudio -Version 2.2.1

Another option to download the assemblies is to use the dotnet CLI, available when installing the .NET SDK. I personally use this:

try {
    $framework = 'netstandard2.0'
    $packagename = 'NAudio'
    dotnet new classlib -f $framework -o "$packagename.package"
    Push-Location "$packagename.package"
    dotnet add package $packagename
    dotnet publish --configuration Release -o lib
}
finally {
    Pop-Location
}

You should have all required assemblies after:

Lastly, using the 2.2.1 version of this package, the following code should list all processes using an audio device.

try {
    Add-Type -Path .\NAudio.package\lib\*.dll
    $deviceEnumerator = [NAudio.CoreAudioApi.MMDeviceEnumerator]::new()
    $audioEndPoints = $deviceEnumerator.EnumerateAudioEndPoints(
        [NAudio.CoreAudioApi.DataFlow]::Render,
        [NAudio.CoreAudioApi.DeviceState]::Active)

    $result = $audioEndPoints | ForEach-Object {
        $sessions = $_.AudioSessionManager.Sessions

        for ($i = 0; $i -lt $sessions.Count; $i++) {
            $session = $sessions[$i]
            # Idle process, we can skip this
            if ($session.GetProcessID -eq 0) {
                continue
            }

            [pscustomobject]@{
                Device             = $_.FriendlyName
                ProcessId          = $session.GetProcessID
                ProcessDisplayName = (Get-Process -Id $session.GetProcessID).ProcessName
                State              = $session.State
                IsMuted            = $session.SimpleAudioVolume.Mute
                Volume             = $session.SimpleAudioVolume.Volume
            }

            $session.Dispose()
        }

        $_.Dispose()
    }
}
finally {
    if ($deviceEnumerator) {
        $deviceEnumerator.Dispose()
    }
}

# Here is the output:
$result

You could filter this output for those objects where the .State property is equal to AudioSessionState.AudioSessionStateActive to find only those processes reproducing audio at the moment.

$result | Where-Object {
    $_.State -eq [NAudio.CoreAudioApi.Interfaces.AudioSessionState]::AudioSessionStateActive
}