How to time-shift audio on iPhone

This is similar to The Pitch Shift question, except I want to keep my audio at the same pitch, but play it s开发者_如何学Clower or faster -- time shift it. (On the iPhone.)

Can anyone point me to a library, tutorial or other reading to help with that?

Thanks!

Isn't this essentially the same thing? For example, if you pitch-shift something up an octave, then play it back at half speed, then it will play at the original pitch, but last twice as long...

A "time shift" is simply a delay. "Time Stretching" is what you will want, which is the reciprocal case to pitch shifting. As others have mentioned, Dirac should fit the bill.