global $iAudioSwitched 
Global $oErrorHandler = ObjEvent("AutoIt.Error", "_ErrFunc")
Func _ErrFunc($oError)
ConsoleWrite("COM Error, ScriptLine(" & $oError.scriptline & ") : Number 0x" & Hex($oError.number, 8) & " - " & $oError.windescription & @CRLF)
EndFunc

Func _IMMNotificationClient_OnDeviceStateChanged($hresult, $wstr, $dword)
#forceref $hresult
Return 0 ; S_OK
EndFunc
Func _IMMNotificationClient_OnDeviceAdded($hresult, $wstr)
#forceref $hresult
Return 0 ; S_OK
EndFunc
Func _IMMNotificationClient_OnDeviceRemoved($hresult, $wstr)
#forceref $hresult
Return 0 ; S_OK
EndFunc
Func _IMMNotificationClient_OnDefaultDeviceChanged($hresult, $dword1, $dword2, $wstr)
#forceref $hresult
$iAudioSwitched = TimerInit()
Return 0 ; S_OK
EndFunc

Func _IMMNotificationClient_OnPropertyValueChanged($hresult, $wstr, $int64)
#forceref $hresult
Return 0 ; S_OK
EndFunc

Func ObjectFromDtag($sFunctionPrefix, $tagInterface, ByRef $tInterface)
Local Const $tagIUnknown = "QueryInterface hresult(ptr;ptr*);" & _
"AddRef dword();" & _
"Release dword();"
; Adding IUnknown methods
$tagInterface = $tagIUnknown & $tagInterface
Local Const $PTR_SIZE = DllStructGetSize(DllStructCreate("ptr"))
; Below line really simple even though it looks super complex. It's just written weird to fit one line, not to steal your eyes
Local $aMethods = StringSplit(StringReplace(StringReplace(StringReplace(StringReplace(StringTrimRight(StringReplace(StringRegExpReplace($tagInterface,"\h*(\w+)\h*(\w+\*?)\h*(\((.*?)\))\h*(;|;*\z)", "$1\|$2;$4" & @LF), ";" & @LF, @LF), 1), "object", "idispatch"), "variant*", "ptr"), "hresult", "long"),"bstr", "ptr"), @LF, 3)
Local $iUbound = UBound($aMethods)
Local $sMethod, $aSplit, $sNamePart, $aTagPart, $sTagPart, $sRet, $sParams
; Allocation. Read http://msdn.microsoft.com/en-us/library/ms810466.aspx to see why like this (object + methods):
$tInterface = DllStructCreate("ptr[" & $iUbound + 1 & "]")
If @error Then Return SetError(1, 0, 0)
For $i = 0 To $iUbound - 1
$aSplit = StringSplit($aMethods[$i], "|", 2)
If UBound($aSplit) <> 2 Then ReDim $aSplit[2]
$sNamePart = $aSplit[0]
$sTagPart = $aSplit[1]
$sMethod = $sFunctionPrefix & $sNamePart
$aTagPart = StringSplit($sTagPart, ";", 2)
$sRet = $aTagPart[0]
$sParams = StringReplace($sTagPart, $sRet, "", 1)
$sParams = "ptr" & $sParams
DllStructSetData($tInterface, 1, DllCallbackGetPtr(DllCallbackRegister($sMethod, $sRet, $sParams)), $i + 2) ; Freeing is left to AutoIt.
Next
DllStructSetData($tInterface, 1, DllStructGetPtr($tInterface) + $PTR_SIZE) ; Interface method pointers are actually pointer size away
Return ObjCreateInterface(DllStructGetPtr($tInterface), "", $tagInterface, False) ; and first pointer is object pointer that's wrapped
EndFunc
Func _UnregisterEndpointNotificationCallback()
$o_MMDeviceEnumerator.UnregisterEndpointNotificationCallback($p_IMMNotificationClient)
EndFunc

FUNC outputChanged()
if $iAudioSwitched and TimerDiff($iAudioSwitched) > 250 then
$iAudioSwitched = 0
RETURN 1
ELSE
RETURN 0
endif
EndFunc