[linux-audio-user] extreme time stretching

derek holzer derek at x-i.net
Mon Mar 15 19:09:17 EST 2004

Doing some quick experiments with Soundtouch, I hear that it probably 
isn't going to work for "extreme" timestretching. Even doubling the 
length of a 4 minute soundfile results in *very* noticeable artifacts... 
a kind of stuttering effect as the samples get pulled apart. You won't 
be making a 24 hour Beethoven stretch with this one...

Seems like an FFT-based approach, or a very good synchronous 
granulation, might be better. Pure Data has a nice phase vocoder demo 
patch in its documentation. You'll have to fiddle with it to get stereo, 
of course. But hey, it's only a help patch! ;-)

Other option is the Synchgrain external for PD, as I might have 
mentioned earlier. I haven't tested the limits of it yet, but I know 
that it sounded smooth at pretty slow playbacks.


derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 173:
"Voice your suspicions"

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