unnecessary data in an mp4

[flannob]

Greetings
An mp4 file has on its upper left side unnecessary data in green.
The includes; source file name (an mkv, though I'm mplaying mp4 file), decoder, running frame and play time, remaining time, frame type and frame duration.
It looks like someone converted mkv to mp4 and left this info.
Does anyone knows how to eliminate it?
maybe convert back with some program?
thanks

[Baldrick]

Try first play your mp4 with another player like vlc media player to be sure it's not any codec(like ffdshow) that shows this information.

But if it's hardcoded in the video must you blur or crop it.