Soft Subs Issue in MPV Format

So I have some nice, high quality mkv format anime with soft subs that I am trying to convert into mpv in order for them to work with my iPod Touch. I'm using Handbrake to do this but there seems to be an issue. From what I observed, it appears as if MPV only supports one line of subtitles at a time and there is a minimum amount of time a subtitle must remain on the screen. Because of this, as soon as the opening theme starts playing, it would begin alternating between the Romaji and English subs for the song instead of displaying the Romaji on the top of the screen and English on the bottom. Unfortunately, this throws of the timing of the subs after the OP considerably. Any advice on how to fix this?