Compute spectrum faster than runtime

[hkjels]

Is there a way to compute spectrum of an audiofile faster than playback?
Any ideas on the subject matter is appreciated..
Thank you in advance..

[panel]

There is AIR app that can be used to mix sounstracks (I just can't recoll the name), so I am guessing that it is possibe in flash to, but I am affraid that you have to analise it by your own ;/