I am unsure what your problem is. If it is about centering the videoview, you could try the following code in your Prepared event:
B4X:
Sub CenterVideoView
If GetDeviceLayoutValues.Width < GetDeviceLayoutValues.Height Then 'portrait
vvvit5.Top = (100%y - vvvit5.Height) / 2
Else if GetDeviceLayoutValues.Width > GetDeviceLayoutValues.Height Then 'landscape
vvvit5.Left = (100%x - vvvit5.Width) / 2
vvvit5.Top = (100%y - vvvit5.Height) / 2
End If
End Sub