[PD] channels and dac

Atte André Jensen atte.jensen at gmail.com
Mon Sep 17 11:30:55 CEST 2007


Derek Holzer wrote:

> Well, without any flags defined by the starting command or the saved 
> settings, then PD would start with two channels (stereo) and adding more 
> with the [adc~] or [dac~] would have no effect.

Ok, so I need to specify on the commandline how many channels I need...

> I can tell you for sure that extra channels add extra CPU, due to PD 
> maintaining connections with the audio drivers. I notice this when, for 
> example, I use my Hammefall DSP with -channels 18 instead of -channels 2 
> or -channels 8 or whatever. Some audio drivers are "greedier" than 
> others, so switching between them can show you a difference in load.

Ok

> Of course, you can always test these things yourself ;-)

Sure, 32 channels, pd idle uses 3,3%cpu, 2 channels, pd idle uses 2%. 
This is on my IBM T41  laptop running jack at 128/3 (latency 8,71 ms).

But I was wondering if it had any impact that would be sporadic, but it 
seems not. However I'll modify my startup script to start with 
appropriate number of channels...

-- 
peace, love & harmony
Atte

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