Well I have not used that library before but if you are not looking to embed the logo in the video then you can just add imageview on top of the video control at the corner where you want it with the logo on it
This is the code that gets the image from the camera preview and sends it:
B4X:
Sub Camera1_Preview (PreviewPic() As Byte)
If DateTime.Now > lastPreviewSaved + IntervalMs Then
Dim jpeg() As Byte = camEx.PreviewImageToJpeg(PreviewPic, 70)
lastPreviewSaved = DateTime.Now
Starter.manager.NewBitmap(jpeg)
End If
End Sub
You will need to load the bitmap with a canvas and then draw the logo. Take the canvas bitmap and send it.
Make sure to reuse the same canvas each frame.