Closed Captions (not subtitles) in MP4

[Elrik]

Is it possible to have true closed captions in MP4 streams? I don't mean regular subtitles but actual CCs. A lot of DVDs have closed captions as an alternative to subtitles, and I actually prefer them a little better. The reason is that they often include more info. For example, when a new person speaks in a dialoge, it shows their name before their line. Also, for instance, in a battle scene of "Return of the King", there's a chant of the elephant/olephaunt army, and CCs show "[HARADRIM CHANT]", while regular subtitles show nothing. It may seem like minor things but in certain situations they are a pleasant addition. Although in some rare situations may be a distraction too. Still, I'd like that option. I know that hardly any DVD players fully support MP4 videos but it would be nice to add an additional CC stream into a video for when a stand-alone support is better.

Or is it possible to convert a DVD CC stream into one of the regular MP4 subtitle formats with the correct timing preserved? If so, how?

Thanks!

PS Please don't tell me to use DVD-R+MPEG-2 if I want CCs. I already know I can. I simply want to know if it's possible in MP4s. :p