Audio Stretching An Audioclip Without Changing It's Pitch (sync To Humanoid Animation)?

I have several humanoid animation that I would like to sync audioclips to, but the animation lengths can differ slightly in length compared to the audioclip (and I have very little ability to alter the animation controller or any keyframe data).

I am however able to calculate a multiplier that compensates for the difference, when I apply it to the pitch of the audioSource I can sometimes hear the that pitch is too far in one direction (Slightly too high/low pitch).

Is it possible (in Unity) to change the speed of an audioclip but not affect the pitch of the clip?

I have some experience working with raw (unmodified) wav data, but I have no idea how to "stretch" the audio data to a desired time duration.

Any ideas on how to do this would be extremely useful!

 

I also need this capability. I have a slide-whistle sound that needs to play while a character falls, which can vary in time.

 

I ended up not needing this feature for my project. However I did learn a bit about TDPSOLA algorithm which was what I was looking for. One very valuable resource I found during my research was a website that showed how to create a Audacity project then manually process the audio data (splice and overlap) exactly as the TDPSOLA algorithm - and is very easy to follow:

http://www.speech.zone/td-psola-the-hard-way/