[PD] Change pitch without changing length of a audio stream ?

Charles Goyard cg at fsck.fr
Fri Sep 21 09:05:01 CEST 2012

Hi list,

In a installation I'm building, I use veejay (veejayhq.net) for video
display, and route the audio of the video for further mixing in pd. This
works very well.

Under some circumstances, I change the video playback speed. Veejay has
a feature called "trickplay" that adjusts the audio to the video length
by changing the pitch much like a 33rpm vynil record played at 45rpm.

What I want is keep the original pitch of the sound. So I figured out
timestretching is what to do. I can send the speed factor of the video
to pd. So I tried the timestretch~ external, the vocoder example (got
this advice from list archive). They both sound terrible, even with the
audio files from the examples (bell.aiff).

So is it something doable in real-time or do I have to look for a
workaround ? Any advice is welcome.


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