I don't think so...they rely upon files and code only in miui...however there are certain roms that have modified variants of the camera and music player
I know liquid rom has a version of the camera as an downloadable alternative camera app (although last time I tried it, it didn't work)
And I know sourcery rom has a version of the miui music player, also as an alternative app
However be aware that in both cases those apps aren't exactly the same as the miui apps
That's too bad. Since I've been using miui, I've grown to love the camera and music player. However, there are certain things that don't work very well that I need to work for my job. I'm gonna have to switch roms to something that is more stable. Which sucks because I love the way miui looks and feels. Maybe I'll search around for some apps that are similar, cuz I really am not a fan of the stock camera or music player.