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I need to control the volume level of the audio produced by a specific application. I have found Simon's simple & neat answer for a similar question here, but it enumerates audio-generating applications by Display-Name, which for some applications - is empty, and hence cannot be used to detect the target application (whose volume is to be controlled).
Hence, I'm looking for a very similar solution, enumerating audio-playing applications' process IDs, through which I could detect applications' actual names (process names & main window titles).
I'm using VB.Net 2010, for Windows 7.
255
Here is a set of utility C# classes that allow you to get information on audio devices and audio session, including process information. They use the Windows Core Audio Library, and only work on Windows 7 or higher:
// sample program
class Program
{
static void Main(string[] args)
{
// dump all audio devices
foreach (AudioDevice device in AudioUtilities.GetAllDevices())
{
Console.WriteLine(device.FriendlyName);
}
// dump all audio sessions
foreach (AudioSession session in AudioUtilities.GetAllSessions())
{
if (session.Process != null)
{
// only the one associated with a defined process
Console.WriteLine(session.Process.ProcessName);
}
}
}
}
// audio utilities
public static class AudioUtilities
{
private static IAudioSessionManager2 GetAudioSessionManager()
{
IMMDevice speakers = GetSpeakers();
if (speakers == null)
return null;
// win7+ only
object o;
if (speakers.Activate(typeof(IAudioSessionManager2).GUID, CLSCTX.CLSCTX_ALL, IntPtr.Zero, out o) != 0 || o == null)
return null;
return o as IAudioSessionManager2;
}
public static AudioDevice GetSpeakersDevice()
{
return CreateDevice(GetSpeakers());
}
private static AudioDevice CreateDevice(IMMDevice dev)
{
if (dev == null)
return null;
string id;
dev.GetId(out id);
DEVICE_STATE state;
dev.GetState(out state);
Dictionary<string, object> properties = new Dictionary<string, object>();
IPropertyStore store;
dev.OpenPropertyStore(STGM.STGM_READ, out store);
if (store != null)
{
int propCount;
store.GetCount(out propCount);
for (int j = 0; j < propCount; j++)
{
PROPERTYKEY pk;
if (store.GetAt(j, out pk) == 0)
{
PROPVARIANT value = new PROPVARIANT();
int hr = store.GetValue(ref pk, ref value);
object v = value.GetValue();
try
{
if (value.vt != VARTYPE.VT_BLOB) // for some reason, this fails?
{
PropVariantClear(ref value);
}
}
catch
{
}
string name = pk.ToString();
properties[name] = v;
}
}
}
return new AudioDevice(id, (AudioDeviceState)state, properties);
}
public static IList<AudioDevice> GetAllDevices()
{
List<AudioDevice> list = new List<AudioDevice>();
IMMDeviceEnumerator deviceEnumerator = null;
try
{
deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());
}
catch
{
}
if (deviceEnumerator == null)
return list;
IMMDeviceCollection collection;
deviceEnumerator.EnumAudioEndpoints(EDataFlow.eAll, DEVICE_STATE.MASK_ALL, out collection);
if (collection == null)
return list;
int count;
collection.GetCount(out count);
for (int i = 0; i < count; i++)
{
IMMDevice dev;
collection.Item(i, out dev);
if (dev != null)
{
list.Add(CreateDevice(dev));
}
}
return list;
}
private static IMMDevice GetSpeakers()
{
// get the speakers (1st render + multimedia) device
try
{
IMMDeviceEnumerator deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());
IMMDevice speakers;
deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out speakers);
return speakers;
}
catch
{
return null;
}
}
public static IList<AudioSession> GetAllSessions()
{
List<AudioSession> list = new List<AudioSession>();
IAudioSessionManager2 mgr = GetAudioSessionManager();
if (mgr == null)
return list;
IAudioSessionEnumerator sessionEnumerator;
mgr.GetSessionEnumerator(out sessionEnumerator);
int count;
sessionEnumerator.GetCount(out count);
for (int i = 0; i < count; i++)
{
IAudioSessionControl ctl;
sessionEnumerator.GetSession(i, out ctl);
if (ctl == null)
continue;
IAudioSessionControl2 ctl2 = ctl as IAudioSessionControl2;
if (ctl2 != null)
{
list.Add(new AudioSession(ctl2));
}
}
Marshal.ReleaseComObject(sessionEnumerator);
Marshal.ReleaseComObject(mgr);
return list;
}
public static AudioSession GetProcessSession()
{
int id = Process.GetCurrentProcess().Id;
foreach (AudioSession session in GetAllSessions())
{
if (session.ProcessId == id)
return session;
session.Dispose();
}
return null;
}
[DllImport("ole32.dll")]
private static extern int PropVariantClear(ref PROPVARIANT pvar);
[ComImport]
[Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")]
private class MMDeviceEnumerator
{
}
[Flags]
private enum CLSCTX
{
CLSCTX_INPROC_SERVER = 0x1,
CLSCTX_INPROC_HANDLER = 0x2,
CLSCTX_LOCAL_SERVER = 0x4,
CLSCTX_REMOTE_SERVER = 0x10,
CLSCTX_ALL = CLSCTX_INPROC_SERVER | CLSCTX_INPROC_HANDLER | CLSCTX_LOCAL_SERVER | CLSCTX_REMOTE_SERVER
}
private enum STGM
{
STGM_READ = 0x00000000,
}
private enum EDataFlow
{
eRender,
eCapture,
eAll,
}
private enum ERole
{
eConsole,
eMultimedia,
eCommunications,
}
private enum DEVICE_STATE
{
ACTIVE = 0x00000001,
DISABLED = 0x00000002,
NOTPRESENT = 0x00000004,
UNPLUGGED = 0x00000008,
MASK_ALL = 0x0000000F
}
[StructLayout(LayoutKind.Sequential)]
private struct PROPERTYKEY
{
public Guid fmtid;
public int pid;
public override string ToString()
{
return fmtid.ToString("B") + " " + pid;
}
}
// NOTE: we only define what we handle
[Flags]
private enum VARTYPE : short
{
VT_I4 = 3,
VT_BOOL = 11,
VT_UI4 = 19,
VT_LPWSTR = 31,
VT_BLOB = 65,
VT_CLSID = 72,
}
[StructLayout(LayoutKind.Sequential)]
private struct PROPVARIANT
{
public VARTYPE vt;
public ushort wReserved1;
public ushort wReserved2;
public ushort wReserved3;
public PROPVARIANTunion union;
public object GetValue()
{
switch (vt)
{
case VARTYPE.VT_BOOL:
return union.boolVal != 0;
case VARTYPE.VT_LPWSTR:
return Marshal.PtrToStringUni(union.pwszVal);
case VARTYPE.VT_UI4:
return union.lVal;
case VARTYPE.VT_CLSID:
return (Guid)Marshal.PtrToStructure(union.puuid, typeof(Guid));
default:
return vt.ToString() + ":?";
}
}
}
[StructLayout(LayoutKind.Explicit)]
private struct PROPVARIANTunion
{
[FieldOffset(0)]
public int lVal;
[FieldOffset(0)]
public ulong uhVal;
[FieldOffset(0)]
public short boolVal;
[FieldOffset(0)]
public IntPtr pwszVal;
[FieldOffset(0)]
public IntPtr puuid;
}
[Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IMMDeviceEnumerator
{
[PreserveSig]
int EnumAudioEndpoints(EDataFlow dataFlow, DEVICE_STATE dwStateMask, out IMMDeviceCollection 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(IMMNotificationClient pClient);
[PreserveSig]
int UnregisterEndpointNotificationCallback(IMMNotificationClient pClient);
}
[Guid("7991EEC9-7E89-4D85-8390-6C703CEC60C0"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IMMNotificationClient
{
void OnDeviceStateChanged([MarshalAs(UnmanagedType.LPWStr)] string pwstrDeviceId, DEVICE_STATE dwNewState);
void OnDeviceAdded([MarshalAs(UnmanagedType.LPWStr)] string pwstrDeviceId);
void OnDeviceRemoved([MarshalAs(UnmanagedType.LPWStr)] string deviceId);
void OnDefaultDeviceChanged(EDataFlow flow, ERole role, string pwstrDefaultDeviceId);
void OnPropertyValueChanged([MarshalAs(UnmanagedType.LPWStr)] string pwstrDeviceId, PROPERTYKEY key);
}
[Guid("0BD7A1BE-7A1A-44DB-8397-CC5392387B5E"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IMMDeviceCollection
{
[PreserveSig]
int GetCount(out int pcDevices);
[PreserveSig]
int Item(int nDevice, out IMMDevice ppDevice);
}
[Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IMMDevice
{
[PreserveSig]
int Activate([MarshalAs(UnmanagedType.LPStruct)] Guid riid, CLSCTX dwClsCtx, IntPtr pActivationParams, [MarshalAs(UnmanagedType.IUnknown)] out object ppInterface);
[PreserveSig]
int OpenPropertyStore(STGM stgmAccess, out IPropertyStore ppProperties);
[PreserveSig]
int GetId([MarshalAs(UnmanagedType.LPWStr)] out string ppstrId);
[PreserveSig]
int GetState(out DEVICE_STATE pdwState);
}
[Guid("6f79d558-3e96-4549-a1d1-7d75d2288814"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IPropertyDescription
{
[PreserveSig]
int GetPropertyKey(out PROPERTYKEY pkey);
[PreserveSig]
int GetCanonicalName(out IntPtr ppszName);
[PreserveSig]
int GetPropertyType(out short pvartype);
[PreserveSig]
int GetDisplayName(out IntPtr ppszName);
// WARNING: the rest is undefined. you *can't* implement it, only use it.
}
[Guid("886d8eeb-8cf2-4446-8d02-cdba1dbdcf99"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IPropertyStore
{
[PreserveSig]
int GetCount(out int cProps);
[PreserveSig]
int GetAt(int iProp, out PROPERTYKEY pkey);
[PreserveSig]
int GetValue(ref PROPERTYKEY key, ref PROPVARIANT pv);
[PreserveSig]
int SetValue(ref PROPERTYKEY key, ref PROPVARIANT propvar);
[PreserveSig]
int Commit();
}
[Guid("BFA971F1-4D5E-40BB-935E-967039BFBEE4"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IAudioSessionManager
{
[PreserveSig]
int GetAudioSessionControl([MarshalAs(UnmanagedType.LPStruct)] Guid AudioSessionGuid, int StreamFlags, out IAudioSessionControl SessionControl);
[PreserveSig]
int GetSimpleAudioVolume([MarshalAs(UnmanagedType.LPStruct)] Guid AudioSessionGuid, int StreamFlags, ISimpleAudioVolume AudioVolume);
}
[Guid("77AA99A0-1BD6-484F-8BC7-2C654C9A9B6F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IAudioSessionManager2
{
[PreserveSig]
int GetAudioSessionControl([MarshalAs(UnmanagedType.LPStruct)] Guid AudioSessionGuid, int StreamFlags, out IAudioSessionControl SessionControl);
[PreserveSig]
int GetSimpleAudioVolume([MarshalAs(UnmanagedType.LPStruct)] Guid AudioSessionGuid, int StreamFlags, ISimpleAudioVolume AudioVolume);
[PreserveSig]
int GetSessionEnumerator(out IAudioSessionEnumerator SessionEnum);
[PreserveSig]
int RegisterSessionNotification(IAudioSessionNotification SessionNotification);
[PreserveSig]
int UnregisterSessionNotification(IAudioSessionNotification SessionNotification);
int RegisterDuckNotificationNotImpl();
int UnregisterDuckNotificationNotImpl();
}
[Guid("641DD20B-4D41-49CC-ABA3-174B9477BB08"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IAudioSessionNotification
{
void OnSessionCreated(IAudioSessionControl NewSession);
}
[Guid("E2F5BB11-0570-40CA-ACDD-3AA01277DEE8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface IAudioSessionEnumerator
{
[PreserveSig]
int GetCount(out int SessionCount);
[PreserveSig]
int GetSession(int SessionCount, out IAudioSessionControl Session);
}
[Guid("bfb7ff88-7239-4fc9-8fa2-07c950be9c6d"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IAudioSessionControl2
{
// IAudioSessionControl
[PreserveSig]
int GetState(out AudioSessionState pRetVal);
[PreserveSig]
int GetDisplayName([MarshalAs(UnmanagedType.LPWStr)] out string pRetVal);
[PreserveSig]
int SetDisplayName([MarshalAs(UnmanagedType.LPWStr)]string Value, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
[PreserveSig]
int GetIconPath([MarshalAs(UnmanagedType.LPWStr)] out string 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(IAudioSessionEvents NewNotifications);
[PreserveSig]
int UnregisterAudioSessionNotification(IAudioSessionEvents NewNotifications);
// IAudioSessionControl2
[PreserveSig]
int GetSessionIdentifier([MarshalAs(UnmanagedType.LPWStr)] out string pRetVal);
[PreserveSig]
int GetSessionInstanceIdentifier([MarshalAs(UnmanagedType.LPWStr)] out string pRetVal);
[PreserveSig]
int GetProcessId(out int pRetVal);
[PreserveSig]
int IsSystemSoundsSession();
[PreserveSig]
int SetDuckingPreference(bool optOut);
}
[Guid("F4B1A599-7266-4319-A8CA-E70ACB11E8CD"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IAudioSessionControl
{
[PreserveSig]
int GetState(out AudioSessionState pRetVal);
[PreserveSig]
int GetDisplayName([MarshalAs(UnmanagedType.LPWStr)] out string pRetVal);
[PreserveSig]
int SetDisplayName([MarshalAs(UnmanagedType.LPWStr)]string Value, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
[PreserveSig]
int GetIconPath([MarshalAs(UnmanagedType.LPWStr)] out string 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(IAudioSessionEvents NewNotifications);
[PreserveSig]
int UnregisterAudioSessionNotification(IAudioSessionEvents NewNotifications);
}
[Guid("24918ACC-64B3-37C1-8CA9-74A66E9957A8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IAudioSessionEvents
{
void OnDisplayNameChanged([MarshalAs(UnmanagedType.LPWStr)] string NewDisplayName, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
void OnIconPathChanged([MarshalAs(UnmanagedType.LPWStr)] string NewIconPath, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
void OnSimpleVolumeChanged(float NewVolume, bool NewMute, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
void OnChannelVolumeChanged(int ChannelCount, IntPtr NewChannelVolumeArray, int ChangedChannel, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
void OnGroupingParamChanged([MarshalAs(UnmanagedType.LPStruct)] Guid NewGroupingParam, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
void OnStateChanged(AudioSessionState NewState);
void OnSessionDisconnected(AudioSessionDisconnectReason DisconnectReason);
}
[Guid("87CE5498-68D6-44E5-9215-6DA47EF883D8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
private interface ISimpleAudioVolume
{
[PreserveSig]
int SetMasterVolume(float fLevel, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
[PreserveSig]
int GetMasterVolume(out float pfLevel);
[PreserveSig]
int SetMute(bool bMute, [MarshalAs(UnmanagedType.LPStruct)] Guid EventContext);
[PreserveSig]
int GetMute(out bool pbMute);
}
}
public sealed class AudioSession : IDisposable
{
private AudioUtilities.IAudioSessionControl2 _ctl;
private Process _process;
internal AudioSession(AudioUtilities.IAudioSessionControl2 ctl)
{
_ctl = ctl;
}
public Process Process
{
get
{
if (_process == null && ProcessId != 0)
{
try
{
_process = Process.GetProcessById(ProcessId);
}
catch
{
// do nothing
}
}
return _process;
}
}
public int ProcessId
{
get
{
CheckDisposed();
int i;
_ctl.GetProcessId(out i);
return i;
}
}
public string Identifier
{
get
{
CheckDisposed();
string s;
_ctl.GetSessionIdentifier(out s);
return s;
}
}
public string InstanceIdentifier
{
get
{
CheckDisposed();
string s;
_ctl.GetSessionInstanceIdentifier(out s);
return s;
}
}
public AudioSessionState State
{
get
{
CheckDisposed();
AudioSessionState s;
_ctl.GetState(out s);
return s;
}
}
public Guid GroupingParam
{
get
{
CheckDisposed();
Guid g;
_ctl.GetGroupingParam(out g);
return g;
}
set
{
CheckDisposed();
_ctl.SetGroupingParam(value, Guid.Empty);
}
}
public string DisplayName
{
get
{
CheckDisposed();
string s;
_ctl.GetDisplayName(out s);
return s;
}
set
{
CheckDisposed();
string s;
_ctl.GetDisplayName(out s);
if (s != value)
{
_ctl.SetDisplayName(value, Guid.Empty);
}
}
}
public string IconPath
{
get
{
CheckDisposed();
string s;
_ctl.GetIconPath(out s);
return s;
}
set
{
CheckDisposed();
string s;
_ctl.GetIconPath(out s);
if (s != value)
{
_ctl.SetIconPath(value, Guid.Empty);
}
}
}
private void CheckDisposed()
{
if (_ctl == null)
throw new ObjectDisposedException("Control");
}
public override string ToString()
{
string s = DisplayName;
if (!string.IsNullOrEmpty(s))
return "DisplayName: " + s;
if (Process != null)
return "Process: " + Process.ProcessName;
return "Pid: " + ProcessId;
}
public void Dispose()
{
if (_ctl != null)
{
Marshal.ReleaseComObject(_ctl);
_ctl = null;
}
}
}
public sealed class AudioDevice
{
internal AudioDevice(string id, AudioDeviceState state, IDictionary<string, object> properties)
{
Id = id;
State = state;
Properties = properties;
}
public string Id { get; private set; }
public AudioDeviceState State { get; private set; }
public IDictionary<string, object> Properties { get; private set; }
public string Description
{
get
{
const string PKEY_Device_DeviceDesc = "{a45c254e-df1c-4efd-8020-67d146a850e0} 2";
object value;
Properties.TryGetValue(PKEY_Device_DeviceDesc, out value);
return string.Format("{0}", value);
}
}
public string ContainerId
{
get
{
const string PKEY_Devices_ContainerId = "{8c7ed206-3f8a-4827-b3ab-ae9e1faefc6c} 2";
object value;
Properties.TryGetValue(PKEY_Devices_ContainerId, out value);
return string.Format("{0}", value);
}
}
public string EnumeratorName
{
get
{
const string PKEY_Device_EnumeratorName = "{a45c254e-df1c-4efd-8020-67d146a850e0} 24";
object value;
Properties.TryGetValue(PKEY_Device_EnumeratorName, out value);
return string.Format("{0}", value);
}
}
public string InterfaceFriendlyName
{
get
{
const string DEVPKEY_DeviceInterface_FriendlyName = "{026e516e-b814-414b-83cd-856d6fef4822} 2";
object value;
Properties.TryGetValue(DEVPKEY_DeviceInterface_FriendlyName, out value);
return string.Format("{0}", value);
}
}
public string FriendlyName
{
get
{
const string DEVPKEY_Device_FriendlyName = "{a45c254e-df1c-4efd-8020-67d146a850e0} 14";
object value;
Properties.TryGetValue(DEVPKEY_Device_FriendlyName, out value);
return string.Format("{0}", value);
}
}
public string IconPath
{
get
{
const string DEVPKEY_DeviceClass_IconPath = "{259abffc-50a7-47ce-af08-68c9a7d73366} 12";
object value;
Properties.TryGetValue(DEVPKEY_DeviceClass_IconPath, out value);
return string.Format("{0}", value);
}
}
public override string ToString()
{
return FriendlyName;
}
}
public enum AudioSessionState
{
Inactive = 0,
Active = 1,
Expired = 2
}
public enum AudioDeviceState
{
Active = 0x1,
Disabled = 0x2,
NotPresent = 0x4,
Unplugged = 0x8,
}
public enum AudioSessionDisconnectReason
{
DisconnectReasonDeviceRemoval = 0,
DisconnectReasonServerShutdown = 1,
DisconnectReasonFormatChanged = 2,
DisconnectReasonSessionLogoff = 3,
DisconnectReasonSessionDisconnected = 4,
DisconnectReasonExclusiveModeOverride = 5
}
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