[PD] Re: [PD-ot] how low (latency) can you go?

[Roman Haefeli]

On Sat, 2006-12-16 at 20:38 -0500, Mathieu Bouchard wrote:
> On Sun, 17 Dec 2006, Patco wrote:
> > aws a écrit :
> >> A general method for latency measurement of any system is described in 
> >> this paper: Matthew Wright, Ryan Cassidy, Michael Zbyszynski, Audio and 
> >> Gesture Latency Measurements on Linux and OSX, Proceedings of ICMC 
> >> 2004, Miami
> >
> > or just connect ãudio input to audio output of the soundcard and take a 
> > measure with some patch magics.
> 
> Exactly. That's what I said a few mails ago. Try 
> doc/7.stuff/tools/latency.pd ... however it doesn't seem to be super 
> precise. Do you have any ideas on how to make it more precise?


the attached patch has sample precision, but it requires some user
interaction to give you a result (and [dirac~] from zexy).

roman
-------------- next part --------------
#N canvas 193 337 1249 508 10;
#X obj 148 42 metro 500;
#N canvas 0 0 450 300 (subpatch) 0;
#X array scope 1200 float 2;
#X coords 0 1.3 1200 -1.3 1200 200 1;
#X restore 31 290 graph;
#X obj 148 15 tgl 15 0 empty empty empty 0 -6 0 8 -262144 -1 -1 1 1
;
#X text 404 61 2 start the metro in order to send dirac-impulses;
#X text 405 24 1 shortcut out1 of your soundcard with in1;
#X obj 198 194 dac~ 1;
#X obj 198 214 adc~ 1;
#X obj 147 245 dac~ 2;
#X obj 197 245 tabwrite~ scope;
#X text 170 12 start/stop measurement;
#X text 426 39 ('1' can be replaced by any number);
#X text 401 90 3 adjust the delay \, so that the direct impulse is
synced to the incoming impulse and you hear/see only one impuls.;
#X obj 401 159 loadbang;
#X obj 99 64 dirac~;
#X obj 99 108 delwrite~ latencyemu 100;
#X obj 101 169 delread~ latencyemu;
#X floatatom 101 140 5 0 0 0 - - -;
#X text 182 140 <- adjust delay;
#X text 139 140 ms;
#X msg 401 182 \; pd dsp 1 \; scope xticks 0 4.41 10 \;;
#X text 468 274 | 10ms;
#X text 908 274 | 20ms;
#X connect 0 0 8 0;
#X connect 0 0 13 0;
#X connect 2 0 0 0;
#X connect 6 0 7 0;
#X connect 6 0 8 0;
#X connect 12 0 19 0;
#X connect 13 0 5 0;
#X connect 13 0 14 0;
#X connect 15 0 8 0;
#X connect 15 0 7 0;
#X connect 16 0 15 0;