After reading Lee Brimelow’s post about Adjusting audio pitch in Flash Player 10, I’ve thinked about a real pitch shifting solution (adjusting pitch without change of duration).
Then I found a great algorithm here: http://www.dspdimension.com/admin/pitch-shifting-using-the-ft/ and its C# port here http://sites.google.com/site/mikescoderama/pitch-shifting
I’ve ported the code to AS3 then heavily optimized it to get it running under 100% cpu use (of 1 cpu core). I get 45% cpu use with the default parameters on my 2.4GHz PC.
See it in action here (Flash Player 10 required):
You can download the source code here: http://iq12.com/files/pitch_shift/pitch_shift.zip
Music: More Frightened by CandyCash (with permission)