public void forgetFfmpegPath(){
  settings.put(SETTINGS_FFMPEG_PATH,FFMPEG_PATH_UNSET);
}

public void forgetFfmpegPath ( ) { settings . put ( SETTINGS_FFMPEG_PATH , FFMPEG_PATH_UNSET ) ; }
makes the library forget about where the ffmpeg binary was located . useful if you moved ffmpeg to a different location . after calling this function the library will ask you again for the location of ffmpeg . optional .
