Hi!
The jap subs are hardcoded or are they provided with a separate file?
If they are hardsubs you can't remove them (at least not in a simple way.. and the results are not good), otherwise you can remove them simply by dleting the subs file (but I think yours are hardsubbed)
You can add subtitles in 2 ways:
- Add the subtitles to the movie (and maybe you can add a black bar to cover the already present japanese subs and put new subtitles over it), this way the subs will be displayed with every player, also stand alone players, but you'll not be able to remove them (take a look at
this post)
- Add a separated subtitle file (you have to choose the format: SubRip, WinDVD, etc.), this way you'll be able to display or disable them in players like BSplayer! (take a look at
this post)