[PD] pd + midi = glitches [further info]

[derek holzer]

Qjackctl gives some illuminating information on the problem:

02:05:18.063 XRUN callback. (54)
delay of 46451.000 usecs exceeds estimated spare time of 45357.000; 
restart ...
delay of 46451.000 usecs exceeds estimated spare time of 45357.000; 
restart ...
02:05:18.068 XRUN callback. (55)
02:05:36.407 XRUN callback. (56)
delay of 46452.000 usecs exceeds estimated spare time of 45359.000; 
restart ...
delay of 46452.000 usecs exceeds estimated spare time of 45359.000; 
restart ...

Anybody see a pattern? ;-)
I wonder what this "spare time of 45359.000" would mean?

Things which seem to have helped so far:

1) Setting -blocksize to 64 [equal to midi timing]: reduced glitches 
significantly, but not completely. After changing blocksize, I got 
slightly different numbers out of Qjackctl's window:

delay of 45481.000 usecs exceeds estimated spare time of 45332.000; 
restart ...

I guess that means I gained .01 ms by changing the blocksize from 2048 
to 64 ;-)

2) Shut down eth0 and/or removed USB mouse [both eth0 and usb-uhci share 
IRQ 9 with the HDSP]: appeared to reduce glitches, but not completely.

After some experiments, I am a bit happier, but not satisfied. The 
glitches still appear most often when several controls are being used at 
once, but sometimes just for a single controller when  I haven't touched 
them in a while.

Question: can someone explain -sleepgrain to me? I know it affects MIDI, 
but I cannot exactly understand *how* from the docs.

Also, would a higher -audiobuf than 50 or 100 help here? I would rather 
keep latency lower than this, of course...

Thx again for any suggestions,
D.


-- 
derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 162:
"Try faking it"