[PD] jack

=?X-UNKNOWN?Q?g=FCnter_geiger?= geiger at xdv.org
Mon Jul 22 20:06:16 CEST 2002

On Mon, 22 Jul 2002, stefan kersten wrote:
> i just had a thought: since audio is turned off anyway when
> reading patches (correct me if i'm wrong), it might be
> possible to deactivate the jack client for patch loading and
> reactivate it afterwards.

it isnt so at the moment, but it could be done this way.
There are other areas like array loading which might be
problematic, but I think they can be handled, and generally
pd meets the deadlines pretty well.

There isnt too much memory allocation, live patching being the
most problematic case (but loosing this feature would be really bad).

> by 'sample synchronous' i referred to the exchange of data
> generated in realtime: in jack the clients' processing
> callbacks are triggered synchronously once per buffer
> computation; no latency due to intermediate buffering is
> introduced, just like in pd's processing of the dsp chain (the
> only exception being latencies due to graph cycles, in jack
> propably too).

ok, got it, thinking it over it is probably very bad adding some
additional intermediate buffer to the pd adc and dacs to get rid
of the problem, because it would increase latency too much.

Well we can't redesign pd from bottom up to make sure it works,
but I hope that it is tweakable enough to work in practise.

Offering a callback based sound IO could be used to improve performance
when using the portaudio library too.

> > Anyhow, I would be very interested to take a look at your
> > solution.
> i'll package the stuff and send it to you ...

Great !


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