[PD] pd on armv7 (beagleboard): crackles / pcm not available?

Damian Stewart damian.ml at frey.co.nz
Fri Jul 9 13:01:44 CEST 2010

hi all,

i'm trying to get Pd to run on my BeagleBoard, and running into a couple of problems. any help greatly appreciated. this is for an installation of this work: http://ll.frey.co.nz which is due to go live in August at Kapelica Gallery in Ljubljana, Slovenia.

basically, the problem is that instead of sound output i'm getting these crackles:

1. i tried Hans' Reware image ("BeagleBoard Pd, Python, Lua image" from here http://dev.eyebeam.org/projects/reware/wiki/Releases ). i'm not sure what version of Pd this is, but it's using OSS as sound device. this makes nasty crackles, that are related to the volume of the sound output and also to the content of the sound i'm trying to output. the crackles don't go away if i increase the audio buffer to 500ms. they sound a bit like a pot full of popping popcorn : http://soundcloud.com/damian/pure-data-on-beagleboard-sound-issue

2a. (Ubuntu 10.04 installation) i tried apt-get install puredata (v. 0.42-5) on my Ubuntu install, which produces the same kind of audio crackles as the Reware image. 

2b. (after sudo killall xdm) i tried running pd -nogui -alsa -noadc -open my_test_patch.pd, which gives me no sound output at all, just a message that "snd_pcm_open (output): Device or resource busy". 

i know Alsa is working on the Ubuntu install because i can use aplay and mpg123 and get perfect sound output. i don't seem to have OSS available on the Ubuntu image.

i'm running a BeagleBoard C4, and i wonder if the Reware image was only tested on an earlier revision board.

again -- any help greatly appreciated!


damian stewart . @damiannz .  damian at frey.co.nz
frey . contemporary art . http://www.frey.co.nz

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