[PD] Re: [PD-announce] Pd 0.39 test 5 released

Thomas Grill gr at grrrr.org
Mon Aug 22 16:05:10 CEST 2005


Hi Piotr,

> I tried to calculate the latency of my system summing up all 
> pd-buffers, driver buffers, DACs and ADCs latency (given by the 
> manufactorer) but, compared to the measured latency (analog loop-back) 
> I get a difference of ~1.5ms (@fs=48kHz). Thus, I wonder what do I 
> wrong and how to calculate which latency of a system which predicts 
> the correct measurable latency.
>
> Has anybody done a latency calculation and compared it to the measured 
> latency?

i have done this several times with PD and Max and i found it pretty 
straightforward.
It's easiest to express the measured latencies in samples, then you 
might see the connection to hardware buffer size etc.
You can isolate the latencies of the different components by comparing 
digital/analog loopback (ADC/DAC latency), different hardware buffer 
sizes and software IO buffer size (i think this is hardcoded to be 64 
samples in PD).

all the best,
Thomas





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