Changing Beats per Minute of selected song

I am working on an iPhone a开发者_运维问答pplication where I want to change the Beats Per Minute (BPM) of the selected song. I am using AVAsset classes for that.

How it can be implemented? Any code help would be appreciated.

I recently started toying with this, what you need to do is use AudioToolbox to read audio data, AudioToolbox allows you to get the data of most popular file types.

Then use something like "SoundTouch" ( just google this, its opensource ), a C++ library that allows you to stretch soundfiles, it even comes with an example that shows you how to do exactly this. Tried it, works on iOS.

You will need AVAssetReader if you want to access iPod songs and you can only test that code with a real world device and not with the simulator as the simulator has no iPod library.