[PD] getting Pd to run on Raspberry Pi

[Mark Edward Grimm]

great! thanks for all that info miller! let us know when you get USB input sounding good and how you did it.

cheers
m

On Sep 8, 2012, at 1:54 AM, Miller Puckette <msp at ucsd.edu> wrote:

> To Pd list,
> 
> I got my Pi in the mail today (only 2 or 3 weeks after ordering it I think -
> they're starting to catch up with the enormous demand!)  and can report what
> I found works and what not.
> 
> I loaded the Raspian distro (the one everyone suggests) and following the
> blog on :
> http://log.liminastudio.com/programming/running-puredata-on-the-raspberry-pi
> 
> just typed
> 
> pi at raspberrypi ~ $ sudo bash
> root at raspberrypi:/home/pi# apt-get update
> root at raspberrypi:/home/pi# apt-get install puredata
> 
> and then pd ... sort of... runs right away.  I had to fool with some
> glitches though:
> 
> 1.  Pd is version 0.43-2 which doesn't yet know to try to promote itself
> to real-time if it's not root.  (This is only fixed in 0.44 which might not
> make it to Raspian for quite some time.)  A rather bad workaround exists:
> still as root (i.e., after the "sudo" step) type
> 
> root at raspberrypi:/home/pi# chmod 4775 /usr/bin/puredata
> 
> This might be a security risk (if anyone breaks into your Pi they might be
> able to design an exploit to get Pd to promote them to root) but I can't
> say I'm worried about that.  (Speaking of security though, since mine is
> networked and ssh-enabled, I did change the password :)
> 
> I'm having no trouble running Pd via ssh from another computer.  The pi
> user is already in group audio in the Raspian distro.  X windows
> forwarding is also turned on by default - so the only detail you have
> to check is whether your ssh is rinngin with -X set on the originating
> machine.  I did notice that one can't run pd inside sudo and still get 
> X forwarding; you have to stay as the pi user.
> 
> Then about audio.  I can indeed verify that the built-in analogue audio is
> wretched -- in two ways.  First, it's not even functional (and LOUDLY non-
> functional :) until you se the latency to at least 40 msec (it's 25 by
> default in Pd on linux.)  Second, it's bad anyway.  To my ears the alsa
> play program and Pd's test-tone sound equally bad.  There's a modulation that
> is sort of as if a sample out of every 1024 is getting dropped or doubled.
> You can hear the modulation change as the pitch of the test tone goes up and
> down.
> 
> So I pulled out my cheapo USB headset from Gigaware and, with input turned
> off, was able to play the test tone with latency down to 10 msec, and got a
> clean-sounding tone out.  Then, getting overconfident, I turned on audio
> input and although the sound came through it has hiccups and my interface
> froze (had to unplug the headphones to get Pd to bail :)
> 
> So things are sort of working but there's still some tuning to do... I'll
> probably have more to report over the weekend.
> 
> cheers
> Miller
> 
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