Sub Player_TrackChanged
   Dim jo As JavaObject = player1
   Dim TrackGroups As JavaObject = jo.GetFieldJO("player").RunMethod("getCurrentTrackGroups", Null)
   For i = 0 To TrackGroups.GetField("length") - 1
       Dim TrackGroup As JavaObject = TrackGroups.RunMethod("get", Array(i))
       For j = 0 To TrackGroup.GetField("length") - 1
           Dim Format As JavaObject = TrackGroup.RunMethodJO("getFormat", Array(j))
           Dim mime As String = Format.GetField("sampleMimeType")
           Log(mime)
           If mime.StartsWith("audio") Then
               Log("audio track")
           End If
           
       Next
   Next
End Sub