[PD] Pd Vanilla on Raspberry Pi

Mon Aug 13 14:43:43 CEST 2012

Hi all,

I don't know whether this was mentioned here, but the audio output throught
the built in jack is bad because it uses PWM followed by a filter, no real
dedicated dac. You can tweek the settings of Pd for years but you'll never
get an good quality sound out of it.

Pierre.

2012/8/13 Michael Zacherl <sdiy-mz01 at blauwurf.info>

>
> On 12.8.2012, at 23:19 , Stephen Lucas wrote:
>
> > I've gotten my Rpi to run pd-vanilla using the regular apt-get install
> on RPi Wheezy 7/15/2012.
> >
> > I'm using the 3.5mm out jack because that's simpler for me to pipe into
> my monitoring system.
> >
> > I wasn't very systematic about documenting the process but I'll try to
> recount the steps I took to get it running.
>
> besides the output selection issue it's pretty straight forward!
>
> > I did have to do some monkeying with the config.txt to get it to stop
> defaulting to HDMI.
> > http://elinux.org/RPi_config.txt
> >
> > I also did some of these steps which seemed to turn off auto default
> output
> >
> http://raspberrypi.stackexchange.com/questions/44/why-is-my-audio-sound-output-not-working
>
> Thanks for that! I was just about to look that up.
> I didn't run into that until recently when I finally connected the RPi to
> a proper HDMI screen (which I don't have myself)
>
> > I have the audio output set to ALSA (hardware) with 2channels.
>
> AFAIK that's the only way it works.  JACK is not available yet.
>
> > The 3.5mm audio output is a bit dirty sounding. This it really obvious
> with pure tones but not too terrible with more complex sounds. I've heard
> that the HDMI audio output doesn't have this problem as much. I did have to
> turn the output delay up to 500-1000ms and the audio vector to 512.
>
> the 'quality' of the sound from the audio socket is a real pain.
> And it stays like that regardless the settings I have in Pd's audio
> settings.
> At some point I'll investigate the options to connect USB-audio but I'm
> afraid at the current state of the software it will be full of glitches as
> well.
>
> > I got the phase vocoder running and it sounds fine. However, any
> additional CPU work interrupts PD and causes some very nasty full output
> crackles. This includes (what I believe are) CPU rendered mouse cursor
> movements, meaning that touching the mouse usually interrupts audio. This
> is not always predictable as I'm sure there are some background processes
> that are also interfering a little.
>
> It was even worse with the original Debian image the RPi-team released
> (with no fpu enabled).
> It also happens when accessing the SD-card and do other operation (via the
> shell w/ no GUI) or network traffic (I use ssh).
> Compared to earlier versions now it's almost ok-ish but I think there's
> still a lot of room for improvement.
> There's some comment on this:
> http://www.raspberrypi.org/phpBB3//viewtopic.php?f=38&t=10538
> Try loading a patch while audio is on.
>
> So far I absolutely wouldn't consider the RPi as a performance platform
> rather than for installation stuff and the like
> which are more likely to be in a dedicated, sort of optimised headless
> operation.
>
> > I haven't tested any of my really large/intense audio patches to get an
> idea of where the thresholds are.
>
> I got Pd-extended running and I get about 40-50% cpu load with the fiddle~
> help-file plus some extra messaging and no GUI!
> With GUI it goes to over 90% - again, room for improvement, but then ...
> see above.
> My large patches need quite some attention (it's the first time I run Pd
> on Linux BTW :-\  ) but from the experience so far I doubt they will be ok.
> It's just too much.
> I tried Sakonda's old pitch shifter which I ported from Max to Pd some
> time ago and this is working nicely.
> But anything fpu-related will be a challenge.
>
> > My main goal is to get Gem going so I'll send an update when I have more
> progress on that.
>
> I'm curious about that! So far I found out that Gem needs GLX which isn't
> provided by the RPi.
> Didn't do any further reading on this and I don't have any HDMI hardware
> at home so I just used X11 on my Mac,
> where Gem is ok.
>
> In fact we are early adopters doing all this, and it's good to see what's
> possible for the money.
> Then again I think it's important to draw a clear line where the
> application of the RPi makes sense and where not.
> It has quite some potential but also can turn quickly into a time-munching
> critter.
>
> Michael.
>
> PS: I just noticed $0 delivers the same value in every instance. I suspect
> that's caused by using X11.
> Could you PLS verify if it's any different using a local HDMI screen?  thx!
>
>
> > On Sat, Aug 11, 2012 at 1:36 PM, Michael Zacherl <
> sdiy-mz01 at blauwurf.info> wrote:
> >
> > On 11.8.2012, at 19:58 , Michael Zacherl wrote:
> >
> > > it is!
> > > Looking at the http://raspberry.org site the list of interesting or
> just funny
> >
> > sorry, of course this should have been http://raspberrypi.org !
> >
> > --
> > feed your perception: http://blauwurf.at
> > http://soundcloud.com/noiseconformist
> >
> >
> >
> >
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>
> --
> noise chasers: http://blauwurf.at
> http://soundcloud.com/noiseconformist
>
>
>
>
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