vary the speed of playing sound but not the frequency

[David_Lieberman]

We would like to sample sound files and then be able to play them back speeded up or slowed down by an arbitrary percentage without changing the frequency (i.e., no Chipmunk effect). Does anybody know of vi's which will do this for us or have pointers to the mathematics do do this?

David Lieberman

[tbob]

I've heard of this being done with sophisticated electronic equipment using DSP technology, but I have never heard of it done in software.

[DD]

Do you have references already? Here are a couple that I found:

http://www.slaney.org/covell/interval/1997-061/
http://www.kom.e-technik.tu-darmstadt.de/acmmm99/ep/knox/

These aren't recent, but then neither is the problem. You could try a first
cut at compression by discarding low amplitude segments. For a second cut,
try reducing the length of sustained tones. You would probably want to do
this in the frequency domain. If you find anything, please let us know.

"David Lieberman" <x@no.email> wrote in message
news:1122930662503-249006@exchange.ni.com...
> We would like to sample sound files and then be able to play them back
> speeded up or slowed down by an arbitrary percentage without changing the
> frequency (i.e., no Chipmunk effect). Does anybody know of vi's which
> will do this for us or have pointers to the mathematics do do this? David
> Lieberman