[PD] dropout save metro

[Roman Haefeli]

the problem with timer is, that it only sends an output, when banged.
you could bang it with some insane rate using a [metro 1000] and
according to the measured (real)time, you send a bang or not. 

this approach would *might* work, but it has several disadvantages, if i
do understand the underlying architecture of pd correctly. first, you
cannot be sure, that each desired time will be triggered. lets assume
you want to schedule the next 'bang' to 43s297ms, but the output of
[timer] maybe is '43 296', '43 296', '43 298'. in that case '43 297'
won't be hit at all. 
then i think, that this approach wouldn't be accurate at all, since
there is no logical time involved. the advantage of logical time is,
that it doesn't matter at all, when the [metro] object is processed by
pd, the output of it will be accurate (as long there are no dropouts).
with a purely realtime based solution, you'll never know, when exactly
the object, that does the time measuring, is processed. the time, when
[timer] receives your bang is not exactly defined and can happen
anywhere between now and the amount of your buffersize later. 

correct me, if i am wrong, but as i understand pd, there will be no
accurate realtime based solution.

roman


On Fri, 2007-06-22 at 17:56 +0200, Enrique Erne wrote:
> hi
> 
> has anybody built a dropout save metro ... say if pd freezes for a 
> while and comes back that the metro would still be in sync with the 
> 'outside' world. that would be very nice in a life situation.
> 
> some ideas ? do you think it can be done in plain pd?
> 
> i failed when i tried to measure the periods between the 'ticks' and 
> calculated the new delay time.
> 
> i just discovered [time] from zexy which is the system time....
> ... has anyone yet built a metro with [time] ? :)
> 
> eni
> 
> 
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