开发者_开发百科I need to get the current volume of the output to the sound card.
Any ideas how?
You can get at these values using IAudioMeterInformation in the CoreAudio APIs in Vista and Win 7.
Managed wrappers are available in NAudio (get at the AudioMeterInformation from the MMDevice).
static int PlayerVolume()
{
RecordPlayer rp = new RecordPlayer();
rp.PlayerID = -1;
int playerVolume = rp.PlayerVolume;
return playerVolume;
}
from modified Microphone Volume in c# article
I solved this when I was working on a (still yet to be released...) application that initiates some kind of "elevator music" when no other sound is present.
Followed the brilliant tips given by Mark Heath, I got what I wanted :
using NAudio.CoreAudioApi;
MMDeviceEnumerator devEnum = new MMDeviceEnumerator();
MMDevice defaultDevice = devEnum.GetDefaultAudioEndpoint(DataFlow.Render, Role.Multimedia);
string currVolume = "MasterPeakVolume : " + defaultDevice.AudioMeterInformation.MasterPeakValue.ToString();
Look in MSDN information for:
- IMMDeviceCollection, IMMDevice and IAudioEndpointVolume (only Windows Vista, Windows 7).
- mixerGetNumDevs, mixerGetLineControls,...
This is "common" information. It is possible C# has more convenient ways (I do not know).
Maybe the winmm.dll can help you :
From EDDYKT (VB):
Private Const HIGHEST_VOLUME_SETTING = 100 '%
Private Const AUX_MAPPER = -1&
Private Const MAXPNAMELEN = 32
Private Const AUXCAPS_CDAUDIO = 1 ' audio from internal CD-ROM drive
Private Const AUXCAPS_AUXIN = 2 ' audio from auxiliary input jacks
Private Const AUXCAPS_VOLUME = &H1 ' supports volume control
Private Const AUXCAPS_LRVOLUME = &H2 ' separate left-right volume control
Private Const MMSYSERR_NOERROR = 0
Private Const MMSYSERR_BASE = 0
Private Const MMSYSERR_BADDEVICEID = (MMSYSERR_BASE + 2)
Private Type AUXCAPS
wMid As Integer
wPid As Integer
vDriverVersion As Long
szPname As String * MAXPNAMELEN
wTechnology As Integer
dwSupport As Long
End Type
Private Type VolumeSetting
LeftVol As Integer
RightVol As Integer
End Type
Private Declare Function auxGetNumDevs Lib "winmm.dll" () As Long
Private Declare Function auxGetDevCaps Lib "winmm.dll" Alias "auxGetDevCapsA" (ByVal uDeviceID As Long, lpCaps As AUXCAPS, ByVal uSize As Long) As Long
Private Declare Function auxSetVolume Lib "winmm.dll" (ByVal uDeviceID As Long, ByVal dwVolume As Long) As Long
Private Declare Function auxGetVolume Lib "winmm.dll" (ByVal uDeviceID As Long, ByRef lpdwVolume As VolumeSetting) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (hpvDest As Any, hpvSource As Any, ByVal cbCopy As Long)
Private Function nSigned(ByVal lUnsignedInt As Long) As Integer
Dim nReturnVal As Integer ' Return value from Function
If lUnsignedInt > 65535 Or lUnsignedInt < 0 Then
MsgBox "Error in conversion from Unsigned to nSigned Integer"
nSignedInt = 0
Exit Function
End If
If lUnsignedInt > 32767 Then
nReturnVal = lUnsignedInt - 65536
Else
nReturnVal = lUnsignedInt
End If
nSigned = nReturnVal
End Function
Private Function lUnsigned(ByVal nSignedInt As Integer) As Long
Dim lReturnVal As Long ' Return value from Function
If nSignedInt < 0 Then
lReturnVal = nSignedInt + 65536
Else
lReturnVal = nSignedInt
End If
If lReturnVal > 65535 Or lReturnVal < 0 Then
MsgBox "Error in conversion from nSigned to Unsigned Integer"
lReturnVal = 0
End If
lUnsigned = lReturnVal
End Function
Private Function lSetVolume(ByRef lLeftVol As Long, ByRef lRightVol As Long, lDeviceID As Long) As Long
Dim Volume As VolumeSetting, lBothVolumes As Long
Volume.LeftVol = nSigned(lLeftVol * 65535 / HIGHEST_VOLUME_SETTING)
Volume.RightVol = nSigned(lRightVol * 65535 / HIGHEST_VOLUME_SETTING)
'copy our Volume-variable to a long
CopyMemory lBothVolumes, Volume.LeftVol, Len(Volume)
'call the SetVolume-function
lSetVolume = auxSetVolume(lDeviceID, lBothVolumes)
End Function
Private Sub Form_Load()
'KPD-Team 2000
'URL: http://www.allapi.net/
'E-Mail: KPDTeam@Allapi.net
Dim Volume As VolumeSetting, Cnt As Long, AC As AUXCAPS
'set the output to a persistent graphic
Me.AutoRedraw = True
'loop through all the devices
For Cnt = 0 To auxGetNumDevs - 1 'auxGetNumDevs is zero-based
'get the volume
auxGetVolume Cnt, Volume
'get the device capabilities
auxGetDevCaps Cnt, AC, Len(AC)
'print the name on the form
Me.Print "Device #" + Str$(Cnt + 1) + ": " + Left(AC.szPname, InStr(AC.szPname, vbNullChar) - 1)
'print the left- and right volume on the form
Me.Print "Left volume:" + Str$(HIGHEST_VOLUME_SETTING * lUnsigned(Volume.LeftVol) / 65535)
Me.Print "Right volume:" + Str$(HIGHEST_VOLUME_SETTING * lUnsigned(Volume.RightVol) / 65535)
'set the left- and right-volume to 50%
lSetVolume 50, 50, Cnt
Me.Print "Both volumes now set to 50%"
'empty line
Me.Print
Next
End Sub
Or maybe this : http://blackbeltvb.com/index.htm?free/mcisamp.htm
I don't believe there is an easy way to get the current Peak under XP. MIXERCONTROL_CONTROLTYPE_PEAKMETER is present but I believe it is largely unsupported (it is on my current machine). I am guessing you will have create your own method of analysing the current audio output, have a look at the DSP section here.
You can just decide at runtime which method you would like to use, XP and Vista/7 have very different methods of dealing with the audio. Some possibly useful information on this matter I wrote previously can be here.
The MSDN documentation and Larry Osterman's (he is also a member on SO) blog are probably the 2 most useful sources for current windows audio infrastructure in my opinion.
Check out this code from Code Project: LED Style Volume Meter Using DirectX
This article serves as a usage manual for a UserControl I created called AnalogSignalMeter. This control uses Direct3D to paint the control, and DirectSound to sample the audio signal.
It has an AnalogSignalMeter object, that is fired an event which will report the current left and right speaker level.
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