[PD] pd + midi = glitches

derek holzer derek at x-i.net
Sun Mar 21 00:53:34 CET 2004

Hi gang,

Maybe someone can help me out of this latest head-scratcher:

I have noticed that I tend to get audio glitches during performance when 
using external MIDI controllers, using the MIDI-in of my HDSP card under 
Linux [haven't tried any other way, however]. Tonight, experimenting 
with only the "test Audio + MIDI" help patch and my MIDI fader box, I 
found that, yes, MIDI appears to be the cause of the problem. It doesn't 
glitch every time, but it does do it fairly often when changing the 
faders, and never when I don't touch them. Using OSS or Jack does not 
make any difference, although Jack happily reports:

**** alsa_pcm: xrun of at least 0.042 msecs

every time a glitch occurs. I also tried starting pd as -rt [with 
"sudo"] as well as setting the period size of Jack to 2048 [much more 
than an HDSP should need!] and using that in realtime mode as well.

PD + ALSA + HDSP does not work on my setup, although PD + ALSA + i810 
soundcard works fine. Go figure.

Any of you other HDSP users out there see this? I wonder if it has 
anything to do with audio + MIDI sharing one device? Improbable, I know, 
but still....

Any suggestions will be appreciated.


derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 3:
"A very small object
-Its centre"

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