I have noticed that when using FAVC (elementary streams m2v/ac3) to author a DVD using DVDStyler, menus don't work 100% correctly. When you activate a title button, a portion of the clip appears for a fraction of a second then the title begins. I've noticed this only with m2v files. If encoded with TFM which outputs mpv files, this does not occur. On a side note, when converting files with FAVC to create a DVD with menus, it produces the same effect.