[PD] Scheduling events, libpd, and sequencing

Tue Feb 15 16:17:06 CET 2011

On Tue, Feb 15, 2011 at 08:30:00AM -0500, Peter Kirn wrote:
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

You accidently had html-mail switched on. :)

> Thanks for the feedback on the timing discussion; I do feel that was useful.
> At some point, it may even be worth writing up a canonical answer there,
> alongside some tests. This still leaves me puzzling over some questions,
> though, in terms of sequencing events in real time - forgetting, for a
> moment, even those timing implications.
> 
> Let's imagine you have an interface scheduling events from another language,
> and Pd as an engine (increasingly common with libpd) processing those events.
> 
> textfile and qlist each do this, qlist tending to be the more convenient.

In this context qlist and textfile are eqivalent: qlist is just a textfile with
a metro/delay and a sender already built in. Both objects do things inside of
Pd and the metros work with subsample accuracy. I don't think, you can take
them as a model for communication with external processes: Once the file is
loaded into a textfile's or qlist's memory, there's no communication with the
outside world (network, harddisk, other processes) happening anymore.

I think, a better model for realtime interaction might by OSC with timetags.

> But what would be the most efficient way to send events to those objects for
> future scheduling?
> 
> qlist seems to be built for the purpose, but two issues:
> 1. qlist seems confused when there's no text file - and in libpd (or really any real-time process), writing to a textfile seems meaningless.
> 2. qlist would require sending every event - not an entire sequence - one at a time, since it can't process lists.
> 
> With textfile, I can add a list, but then the list gets stored entirely as
> one message - which means to iterate through the list, I have to again split
> it into individual items.

qlist can send lists just fine.  Both qlist and a textfile with sender/outlet
and metro-timing simply send Pd messages like floats, symbols, lists, etc. 
It's up to the composer to define, what's describing an event and what
describes a sequence.

Ciao
-- 
 Frank Barknecht            Do You RjDj.me?          _ ______footils.org__