[PD] timing question

Martin Peach martin.peach at sympatico.ca
Mon Dec 17 16:45:19 CET 2007


If you do something that interacts with reality, like sending something 
through [comport] using [metro] to schedule it, you will find that the 
actual messages show up on the serial connector on either side of the audio 
blocks, so that the average timing over a lot of messages is exact but any 
particular event will be within about 5 ms of the correct time.

Martin


Derek Holzer wrote:
>To: Claude Heiland-Allen <claudiusmaximus at goto10.org>
>CC: pd-list at iem.at
>Subject: Re: [PD] timing question
>Date: Mon, 17 Dec 2007 15:55:28 +0100
>
>Thanks, Zen-Master Claudius. Your quantum revelations still leave me
>wondering, however, what is the minimum time between two events which
>can be scheduled?
>
>I teach my students that the reason you can't send audio to "message"
>(i.e. non-audio) objects is that "message" objects run slower. While
>this may not be "logically" correct to many of the hackers that live on
>this list, it is a convenient way to explain the difference to artists
>just beginning in this world. Block size was the technical answer I gave.
>
>Now that I know this is false, I need a new explanation. Plus I'd like
>to know what the limits of message processing speed are. In "real time",
>please.
>
>best,
>d.
>
>Claude Heiland-Allen wrote:
> > Derek Holzer wrote:
> >> Hi all,
> >>
> >> Charles Henry wrote:
> >>> On Dec 17, 2007 3:03 AM, Frank Barknecht <fbar at footils.org> wrote:
> >>>> Hallo,
> >>>> Charles Henry hat gesagt: // Charles Henry wrote:
> >>>>
> >>>>> [metro 1] creates a bang each millisecond, approximately.  The 
>message
> >>>>> rate is constrained by the block size, so you would want to put 
>[metro
> >>>>> 1] inside of a subpatch with [block~ 1] for best time resolution.
> >>>> That's not true. Message rate is not related to the dsp vector size.
> >>> My mistake.  I thought messages had to run in between dsp blocks.
> >>
> >> Someone please refresh/adjust my memory... what IS the message rate in
> >> PD? I also thought it was related to block size all these years. And
> >> how can it be changed if needed?
> >
> > There is no fixed rate, it's event-based with continuous time (or as
> > continuous as floating point numbers gets you).  But - it works with
> > "logical" time, any relationship to "real" time is purely a coincidence.
> >
> >
> > Claude
>
>--
>derek holzer ::: http://www.umatic.nl ::: 
>http://blog.myspace.com/macumbista
>---Oblique Strategy # 81:
>"Go to an extreme, move back to a more comfortable place"
>
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