With NTP and no tricks, you can get 1-2ms of accuracy, if you buy a
external clock sync device, you can get 10 microseconds. I don't have
a specific software package in mind, its more a technique.
.hc
On Oct 10, 2009, at 5:03 AM, Brian FG Katz wrote:
Dear Mans-Christian,
This is an interesting idea. I first pose a question, to see if it is
suitable for the problem as I understand it. First, you assume that
the CPU
clocks of all machines are synchronized at a sub-sample level. Now,
if you
send a message for an event to occur at t0+20msec, how precise is this
timing executed? Can it execute the function in mid-buffer?
Thanks for your help.
-Brian
---
Brian FG Katz, Ph.D
Audio & Acoustique
LIMSI-CNRS
BP 133
F91403 Orsay
France
tel. (+33) 01 69 85 81 55
fax. (+33) 01.69.85.80.88
e-mail brian.k...@limsi.fr
web_theme: http://www.limsi.fr/Scientifique/aa/thmsonesp/
web_group: http://www.limsi.fr/Scientifique/aa/
-----Message d'origine-----
De : Hans-Christoph Steiner [mailto:h...@at.or.at]
Envoyé : jeudi 8 octobre 2009 19:16
À : Brian FG Katz
Cc : pd-list@iem.at
Objet : Re: [PD] multi-pc synchrony
If you use some kind of time-tagging, which some implementations of
OSC support, then you add add a bit of latency to the whole system and
use that to reduce the inter-machine latency. The basic idea is that
each message has a time tag that marks when that message should take
effect. Then you put that time tag 20ms in the future when you send
it, every machine should have it within 20ms, and then they'll all
execute the message at the same time.
.hc
On Oct 8, 2009, at 6:27 AM, Brian FG Katz wrote:
Dear PD-ers,
We are working on an installation with 4 machines running PD to feed
157
loudspeakers. We are interested in reducing latency to a minimum
between
channels, and especially between machines. The inter-channel latency
in less
than a sample, so all is fine there. For inter-machine latency, we
arrive at
differences on the order of 10msec, close to our minimum audio-
buffer length
of 11msec. Any small audio-buffer and we get audio artifacts.
We are using a word clock synchronizer (Nanosyncs HD; Rosendahl),
but I
don't think that does latency synchronization.
My question, is there another means to improve inter-machine latency
performance other than reducing the audio-buffer?
-Brian
---
Brian FG Katz, Ph.D
Audio & Acoustique
LIMSI-CNRS
BP 133
F91403 Orsay
France
tel. (+33) 01 69 85 81 55
fax. (+33) 01.69.85.80.88
e-mail brian.k...@limsi.fr
web_theme: http://www.limsi.fr/Scientifique/aa/thmsonesp/
web_group: http://www.limsi.fr/Scientifique/aa/
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