[PD] jack clicks but alsa or oss runs smoothly

Iain Mott mott at reverberant.com
Sun May 1 08:37:01 CEST 2005


Hello

I'm running an a Pd patch that reads and writes to disk simultaneously
with a number readsf~ and writesf~ objects. It runs very well using alsa
or with oss emulation but produces occasional clicks when running with
jack. I'm wondering if there's anything I can do to fix this?

Latency is not an issue with this application and i'm running the
following to set up jack:

/usr/bin/jackd -R -dalsa -dhw:0 -r44100 -p2048 -n2 &

Pd includes the following start options: -rt -jack

Have compiled pd-0.38-4 with the following configuration: ./configure
--enable-newhash --enable-jack --enable-fftw --enable-simd
--enable-optimize=pentium4 --enable-threadedsf --enable-atomic –
enable-debug

I'm using a Gentoo 2.6.10 kernel. Also using realtime-lsm to get
non-root realtime priority (althought this feature doesn't seem to
create any audible benefits or problems in this particular patch). The
computer is a Compaq Presario R3000 laptop using atiixp alsa drivers.

alsa is being loaded as a module and not compiled into the kernel
(haven't tried compiling into the kernel)

When clicks occur, Pd reports errors such as:
     8.41       A/D/A sync
    18.41       A/D/A sync
    18.41       A/D/A sync
    18.78       unknown
    18.78       unknown
    18.78       unknown

Can anyone please suggest what might be causing the glitches? (Ardour
by-the-way seems to run well heavily loaded, without any glitches)

Best, Iain

_______
Iain Mott
www.reverberant.com 






More information about the Pd-list mailing list