Run script based on sound VU level in vb.net
See the question and my original answer on StackOverflowHere is a C# solution that uses Windows Core Audio Library
This API has the notion of Session (which kinda corresponds to what you see in the Volume Mixer). So, I've provided an AudioSession wrapper class that can give you various information on all current sessions in Windows, with details like the session process id and possibly it's name, display name, icon, etc.
This class also has a GetChannelsPeakValues() methods which uses the IAudioMeterInformation interface to get peak value for each audio channel.
Here is a C# console app example (but the AudioSession class supports any UI technology) that, when ran, will display the peak values for each channel of the chrome browser instance (run some video or sound from the browser and the numbers should start moving). If you don't have chrome, use another process of your choice.
class Program
{
static void Main(string[] args)
{
// Here, I'm just monitoring chrome, one of the possible sessions.
// If you want the whole speakers peak values, use the AudioSession.GetSpeakersChannelsPeakValues() method
foreach (var session in AudioSession.EnumerateAll())
{
if (session.Process?.ProcessName == "chrome")
{
do
{
var values = session.GetChannelsPeakValues();
if (values.Length == 0)
continue;
Console.WriteLine(string.Join(" ", values.Select(v => v.ToString("00%"))));
}
while (true);
}
session.Dispose();
}
}
}
And here is the support C# code:
public class AudioSession : IDisposable
{
private readonly Lazy<Icon> _icon;
private readonly Lazy<Process> _process;
private readonly IAudioSessionControl2 _control;
public AudioSession(IAudioSessionControl2 control)
{
_control = control;
control.GetState(out var state);
State = state;
control.GetGroupingParam(out var guid);
GroupingParam = guid;
IconPath = GetString(control.GetIconPath);
DisplayName = GetString(control.GetDisplayName);
_icon = new Lazy<Icon>(GetIcon, true);
_process = new Lazy<Process>(() => Process.GetProcessById(ProcessId), true);
Id = GetString(control.GetSessionIdentifier);
InstanceId = GetString(control.GetSessionInstanceIdentifier);
control.GetProcessId(out var pid);
ProcessId = pid;
IsSystemSounds = control.IsSystemSoundsSession() == 0;
}
public AudioSessionState State { get; }
public string IconPath { get; }
public string DisplayName { get; }
public Guid GroupingParam { get; }
public Icon Icon => _icon.Value;
public string Id { get; }
public string InstanceId { get; }
public int ProcessId { get; }
public Process Process => _process.Value;
public bool IsSystemSounds { get; }
public float[] GetChannelsPeakValues()
{
var meter = (IAudioMeterInformation)_control;
meter.GetMeteringChannelCount(out var channelCount);
var values = new float[channelCount];
meter.GetChannelsPeakValues(channelCount, values);
return values;
}
private delegate int GetStringFn(out IntPtr ptr);
private static string GetString(GetStringFn fn)
{
fn(out var ptr);
if (ptr == IntPtr.Zero)
return null;
try
{
var s = Marshal.PtrToStringUni(ptr);
if (!string.IsNullOrWhiteSpace(s) && s.StartsWith("@"))
{
var sb = new StringBuilder(256);
if (SHLoadIndirectString(s, sb, sb.Capacity, IntPtr.Zero) == 0)
{
s = sb.ToString();
}
}
return s;
}
finally
{
Marshal.FreeCoTaskMem(ptr);
}
}
private Icon GetIcon()
{
if (string.IsNullOrWhiteSpace(IconPath))
return null;
var index = ParseIconLocationPath(IconPath, out var path);
// note this may only work if the OS bitness is the same as this process bitness
var hIcon = ExtractIcon(IntPtr.Zero, path, index);
return hIcon == IntPtr.Zero ? null : Icon.FromHandle(hIcon);
}
public override string ToString() => DisplayName;
public void Dispose() => _icon.Value?.Dispose();
public static float[] GetSpeakersChannelsPeakValues()
{
// get the speakers (1st render + multimedia) device
var deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());
deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out IMMDevice speakers);
if (speakers == null)
return new float[0];
// get meter information
speakers.Activate(typeof(IAudioMeterInformation).GUID, 0, IntPtr.Zero, out object o);
var meter = (IAudioMeterInformation)o;
if (meter == null)
return new float[0];
meter.GetMeteringChannelCount(out var count);
if (count == 0)
return new float[0];
var values = new float[count];
meter.GetChannelsPeakValues(count, values);
return values;
}
public static IEnumerable<AudioSession> EnumerateAll()
{
// get the speakers (1st render + multimedia) device
var deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());
deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out IMMDevice speakers);
if (speakers == null)
yield break;
// activate the session manager, we need the enumerator
speakers.Activate(typeof(IAudioSessionManager2).GUID, 0, IntPtr.Zero, out object o);
var sessionManager = (IAudioSessionManager2)o;
if (sessionManager == null)
yield break;
// enumerate sessions for on this device
sessionManager.GetSessionEnumerator(out IAudioSessionEnumerator sessionEnumerator);
sessionEnumerator.GetCount(out int count);
for (int i = 0; i < count; i++)
{
sessionEnumerator.GetSession(i, out var sessionControl);
if (sessionControl != null)
{
var meter = sessionControl as IAudioMeterInformation;
yield return new AudioSession(sessionControl);
}
}
}
[DllImport("shlwapi", CharSet = CharSet.Unicode)]
private extern static int SHLoadIndirectString(string pszSource, StringBuilder pszOutBuf, int cchOutBuf, IntPtr ppvReserved);
[DllImport("shlwapi", CharSet = CharSet.Unicode)]
private static extern int PathParseIconLocation(string pszIconFile);
[DllImport("shell32", CharSet = CharSet.Unicode)]
private static extern IntPtr ExtractIcon(IntPtr ptr, string pszExeFileName, int nIconIndex);
private static int ParseIconLocationPath(string location, out string path)
{
if (location == null)
throw new ArgumentNullException(nameof(location));
path = string.Copy(location);
int index = PathParseIconLocation(path);
int pos = path.LastIndexOf('\0');
if (pos >= 0)
{
path = path.Substring(0, pos);
}
if (path.StartsWith("@"))
{
path = path.Substring(1);
}
return index;
}
}
[ComImport]
[Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")]
public class MMDeviceEnumerator
{
}
public enum EDataFlow
{
eRender,
eCapture,
eAll,
EDataFlow_enum_count
}
public enum ERole
{
eConsole,
eMultimedia,
eCommunications,
ERole_enum_count
}
[Guid("a95664d2-9614-4f35-a746-de8db63617e6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public partial interface IMMDeviceEnumerator
{
[PreserveSig]
int EnumAudioEndpoints(EDataFlow dataFlow, uint dwStateMask, out IntPtr ppDevices);
[PreserveSig]
int GetDefaultAudioEndpoint(EDataFlow dataFlow, ERole role, out IMMDevice ppEndpoint);
[PreserveSig]
int GetDevice([MarshalAs(UnmanagedType.LPWStr)] string pwstrId, out IMMDevice ppDevice);
[PreserveSig]
int RegisterEndpointNotificationCallback(IntPtr pClient);
[PreserveSig]
int UnregisterEndpointNotificationCallback(IntPtr pClient);
}
[Guid("d666063f-1587-4e43-81f1-b948e807363f"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public partial interface IMMDevice
{
[PreserveSig]
int Activate([MarshalAs(UnmanagedType.LPStruct)] Guid iid, uint dwClsCtx, [In, Out] IntPtr pActivationParams, [MarshalAs(UnmanagedType.IUnknown)] out object ppInterface);
[PreserveSig]
int OpenPropertyStore(uint stgmAccess, out IntPtr ppProperties);
[PreserveSig]
int GetId(out IntPtr ppstrId);
[PreserveSig]
int GetState(out uint pdwState);
}
[Guid("C02216F6-8C67-4B5B-9D00-D008E73E0064"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IAudioMeterInformation
{
[PreserveSig]
int GetPeakValue(out float pfPeak);
[PreserveSig]
int GetMeteringChannelCount(out int pnChannelCount);
[PreserveSig]
int GetChannelsPeakValues(int u32ChannelCount, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 0)] float[] afPeakValues);
[PreserveSig]
int QueryHardwareSupport(out int pdwHardwareSupportMask);
}
[Guid("77aa99a0-1bd6-484f-8bc7-2c654c9a9b6f"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public partial interface IAudioSessionManager2
{
// IAudioSessionManager
[PreserveSig]
int GetAudioSessionControl(IntPtr AudioSessionGuid, uint StreamFlags, out IAudioSessionControl2 SessionControl);
[PreserveSig]
int GetSimpleAudioVolume(IntPtr AudioSessionGuid, uint StreamFlags, out IntPtr AudioVolume);
// IAudioSessionManager2
[PreserveSig]
int GetSessionEnumerator(out IAudioSessionEnumerator SessionEnum);
[PreserveSig]
int RegisterSessionNotification(IntPtr SessionNotification);
[PreserveSig]
int UnregisterSessionNotification(IntPtr SessionNotification);
[PreserveSig]
int RegisterDuckNotification([MarshalAs(UnmanagedType.LPWStr)] string sessionID, IntPtr duckNotification);
[PreserveSig]
int UnregisterDuckNotification(IntPtr duckNotification);
}
[Guid("E2F5BB11-0570-40CA-ACDD-3AA01277DEE8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IAudioSessionEnumerator
{
[PreserveSig]
int GetCount(out int SessionCount);
[PreserveSig]
int GetSession(int SessionCount, out IAudioSessionControl2 Session);
}
public enum AudioSessionState
{
AudioSessionStateInactive = 0,
AudioSessionStateActive = 1,
AudioSessionStateExpired = 2,
}
[Guid("bfb7ff88-7239-4fc9-8fa2-07c950be9c6d"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public partial interface IAudioSessionControl2
{
// IAudioSessionControl
[PreserveSig]
int GetState(out AudioSessionState pRetVal);
[PreserveSig]
int GetDisplayName(out IntPtr pRetVal);
[PreserveSig]
int SetDisplayName([MarshalAs(UnmanagedType.LPWStr)] string Value, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
[PreserveSig]
int GetIconPath(out IntPtr pRetVal);
[PreserveSig]
int SetIconPath([MarshalAs(UnmanagedType.LPWStr)] string Value, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
[PreserveSig]
int GetGroupingParam(out Guid pRetVal);
[PreserveSig]
int SetGroupingParam([MarshalAs(UnmanagedType.LPStruct)] Guid Override, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
[PreserveSig]
int RegisterAudioSessionNotification(IntPtr NewNotifications);
[PreserveSig]
int UnregisterAudioSessionNotification(IntPtr NewNotifications);
// IAudioSessionControl2
[PreserveSig]
int GetSessionIdentifier(out IntPtr pRetVal);
[PreserveSig]
int GetSessionInstanceIdentifier(out IntPtr pRetVal);
[PreserveSig]
int GetProcessId(out int pRetVal);
[PreserveSig]
int IsSystemSoundsSession();
[PreserveSig]
int SetDuckingPreference(bool optOut);
}