[PD] Interpolating to a higher sample frequency

IOhannes m zmoelnig zmoelnig at iem.at
Sun Mar 13 20:47:57 CET 2005

Niklas Saers wrote:
> Hi,

> interpolation with Pd or how you'd go about doing this. Right now the 
> only option I'm aware of is writing an external with the interpolation 
> and try to spit out the audio at a higher rate than it comes in. Will Pd 

this will not work at all.

> at all allow for this, or is it locked to the sample rate of my 
> hardware? I've been googeling for externals that do this already but 
no, pd can use quite any samplerate (but your hardware might not support 

> found none. For the interpolation I was thinking of using line~, but it 
> doesn't seem fine-grained enough, asking for milliseconds.

no this is something completely different.
[line~] is to convert messages to signals (with slopes), it has nothing 
to do with interpolating signals.

what you are looking for is called "upsampling".

pd's dsp tree needs to have one sub-patch to have a fixed size 
block-size, overlap-factor and sample-rate. (because that is the way how 
pd works.) this is the main reason to not being able to make an external 
that outputs more samples than are coming in (i think max is different here)

anyhow, you can do upsampling (and downsampling) with the third argument 
of the [block~] object.

there is a help-patch in 3.audio.examples/ that explains how to use this 


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