Hmm... unsure. Personally, I have worked with the sdl_mixer a while ago, but never really got too in depth with all of it's functions.

I probably went through all the surface functionality as I do with almost everything new I try out, but I don't recall it being as versatile as it would take to make a fully capable player like WinAmp or anything as complex as that.

To get what you want, some hacking into the innards of the functions might be required.