[PD] Jack, netsend, realtime-mode and all the rest

[Frank Barknecht]

Hi,

in a rather demanding setup I'm currently working on, I use two Pd
instances: one for visuals with Gem, the other running with "-rt" for
audio stuff. Both are connected through netsend/netreceive in UDP
mode, all is happening on Linux.

I have to send quite a lot of data over this net connection (control
data for audio generated from physical models and msd). Generally
however this is no problem: If I run Pd using my laptop's internal
soundcard all is fine. However I would like to use my USB soundcard
instead, which is a Terratec Phase 26 with 2 channels in and 6
channels out. 

Pd seems to be unable to handle this channel combination, so I started
to use Jack. However now my troubles really begin: Somehow I'm not
able to get this combination running stable. I run Jack realtime with
-R and tried various values of -P to set jackd's priority: -P70 up to
-P89.  However with all of these, after some time the audio-Pd starts
to run into a fight with the watchdog: signalling Pd to stop. The
audio-Pd keeps running, however I get regular clicks in the audio
stream. I *suspect* that this has something to do with the network
data, like Pd is not keeping up with receiving the network stuff in
time. Running the audio-Pd with "-noadc" helps a bit, but not for
long. 

So: Does anyone have any tips or tricks how to get a stable Pd in this
situation?  And should jackd run at a higher or at a lower priority
than Pd?

Ciao
-- 
 Frank Barknecht                 _ ______footils.org_ __goto10.org__