Rewind 30 seconds audio and play 2X speed

I have a Query regarding playing audio: Can I rewind the audi开发者_StackOverflowo 30 secs and Play with 2X speed? Is that possible like in Podcasts in iPhone?

Thanks

If you want to speed up sound without making the pitch high and squeaky, then you may need to license a commercial DSP time-pitch stretch library such as Dirac, et.al. (There may be some open source code to do this in Audacity, but I am unaware of a working iOS port of such).