Directshow Audio/Video for Captured device - vb.net

Question

Directshow Audio/Video Capture
In VB.Net, I can capture the video from connected device, but unable to recieve any sound, as speakers are connected. I can play movies and mp3s from MediaPlayer. But, confused, why the sound is not coming. Please guide me to set audio filters in the following code. Please help, kindly make relevant changes in the following code...
Public Function FindCaptureDevice() As IBaseFilter
Debug.WriteLine("Start the Sub FindCaptureDevice")
Dim hr As Integer = 0
Dim classEnum As IEnumMoniker = Nothing
'Dim classEnum1 As IEnumMoniker = Nothing
Dim moniker As IMoniker() = New IMoniker(0) {}
Dim source As Object = Nothing
Dim devEnum As ICreateDevEnum = CType(New CreateDevEnum, ICreateDevEnum)
hr = devEnum.CreateClassEnumerator(FilterCategory.VideoInputDevice, classEnum, 0)
DsError.ThrowExceptionForHR(hr)
Marshal.ReleaseComObject(devEnum)
If classEnum Is Nothing Then
Throw New ApplicationException("No video capture device was detected.\r\n\r\n" & _
"This sample requires a video capture device, such as a USB WebCam,\r\n" & _
"to be installed and working properly. The sample will now close.")
End If
If classEnum.Next(moniker.Length, moniker, IntPtr.Zero) = 0 Then
Dim iid As Guid = GetType(IBaseFilter).GUID
moniker(0).BindToObject(Nothing, Nothing, iid, source)
Else
Throw New ApplicationException("Unable to access video capture device!")
End If
Marshal.ReleaseComObject(moniker(0))
Marshal.ReleaseComObject(classEnum)
Return CType(source, IBaseFilter)
End Function