You are referring to the OSD-messages I think.
So far OSD cannot be switched off; however, what you could do is to select the smallest possible fontsize (e.g. 1pt) for it and "neutral" colours; then the OSD-messages are in fact hardly noticeable (a really tiny narrow line if you know where to look).
You can do so at the "Video"-tab (right-hand side) of "Options"/"Preferences"
(Of course, if you happen to have a black border above your movie, you could select black letters, which - on a black background - are totally invisible)