in \core\gui_lang.c:
"210 \"DOF Calculator\"\n"
"211 \"DOF Calculator->\"\n"
The codes for video settings are:
"233 \"Video Parameters\"\n"
"234 \"Video Parameters->\"\n"
"235 \"Video Mode\"\n"
"236 \"Video Bitrate\"\n"
"237 \"Video Quality\"\n"
So only edit these lines in your lang file, e.g.
233 "Video Parameter"
...