Too many audio dropouts on puredata

kijjaz

Hi again. I've been using Ubuntu/Fedora for electronic/experimental music synthesis/performances and now mostly trying some new ideas on Puredata.

Now I'm mainly on Ubuntu with my not-that-superfast 32-bit laptop PC (but with nVidia for graphics, ok). But there's one thing bugging my mind; when I move puredata things, for example, moving objects, moving graphs, .. etc .. there often occurs some dropouts. But Jack was running smooth and no buffer over/underruns reported, so I see it's dropouts in PD.

For everyday desktop use, graphics is qutie smooth, i mean i can drag some windows around without the audio dropping out, but within PD, the PD audio does drop out quite often although CPU was not working that hard.

There are normally more dropouts than I expect although running not-to-big patches.

What should I do / check to improve this? Or do you guys have this same problem? It seems much smoother on Mac OS X, Windows.

Now I'm using pd-extended installable from .deb from puredata.info. The same problem happened to both vanilla and pd-extended, both stable and nightly builds.

dewdrop_world · Posted: Fri Feb 05, 2010 9:00 pm Post subject:

I'm having the opposite experience on my new netbook. Pd sounds like ass in WIndows (glitches, dropouts) but sounds fine on a simple patch in Linux.

Using puredyne - the new one "carrot & coriander" is nice! SuperCollider works cleanly on it too. (No pre-install of ChucK though... I thought it was there.) The puredyne website says they did a lot of optimization for realtime audio.

herrsteiner · Joined: Mar 10, 2008 Posts: 8 Location: Hamburg

unfortunatly the gui and audio thread in PD is not so separate as it should be, a well known problem. Two things can help:

- start PD with realtime mode, it seems to work for me only via terminal:
pd -rt

when I change it in the gui and restart it doesnt seem to get set.

- increase priority of pd thread
AFAIK pd actually starts two programs and it helps to increase the priority of the acutal sound thread. You can set priorities on the terminal after programs have started with

chrt -p 99 $(pidof pd)

when this helps you might write a small start skript to not have to type in that stuff, maybe something containing the commands like

pd -rt &
sleep 4
chrt -p 99 $(pidof pd)