[PD] Pd + asterisk?

Hans-Christoph Steiner hans at eds.org
Mon Dec 17 07:25:53 CET 2007

This is great news!  I am going to give it a shot as soon as I can,  
hopefully before the end of the year.

As for Jack in Pd, there are a couple of things.  Pd by default uses  
Jack as an audio device, so it should be able to see those ports.   
But I don't think that is very controllable from within Pd.  There  
are some objects that exist but aren't widely used that are for  
connecting Pd and jack channels in a more dynamic manner.  Here are  
the sources:


And thanks for the bug fixes for Pd.  Pd could use a good security  
audit, especially since it is becoming more and more network aware.


On Dec 16, 2007, at 8:48 PM, Russell Bryant wrote:

> Greetings,
> I have been working on Jack support in Asterisk this weekend and I  
> have it
> working, as far as I can tell.  I have a Jack Asterisk dialplan  
> application
> which when executed, creates two jack ports; one port is input and  
> the other is
> output.  These ports let you access the audio that comes from the  
> caller, as
> well as control what audio gets sent back to the caller.  Once I  
> have this
> working well, I will extend the Jack interface to allow you to do  
> fancier
> things.  Right now, the jack interface is the endpoint of the phone  
> call, but it
> would be even more interesting to be able to hook into the audio  
> path of a phone
> call to another destination.
> Anyway, the way that I have tested this is simply by using an  
> application called
> "Patchage".  It is a graphical jack port manager.  When I make a  
> call, I see my
> two jack ports appear.  I can connect them together and everything  
> I say gets
> sent back to me as expected.
> My next step is that I want to figure out how to hook up my ports  
> to a Pd patch,
> but I haven't quite figured out how to use Jack in Pd yet.  I'm  
> going to keep
> working on it, but I figured I would post what I have in case  
> anyone else was
> curious and interested in trying it out.
> Here is what I'm doing to test what I have ...
> 1) Install my branch of Asterisk that contains app_jack.
> $ svn co http://svn.digium.com/svn/asterisk/team/russell/jack  
> asterisk-jack
> $ cd asterisk-jack
> $ ./configure && make
> $ sudo make install
> The jack interface is in apps/app_jack.c in case anyone cares.
> 2) Make an entry in /etc/asterisk/extensions.conf that looks like
> exten => 500,1,Answer()
> exten => 500,n,Jack()
> 3) Make sure jackd is running.  For the sake of efficiency, specify  
> 8 kHz,
> because for most codecs used for phone calls, that's all you get.   
> Also, specify
> 160 frames per period.  For 8 kHz audio, this comes out to 20 ms  
> periods, which
> is generally the packet size used for Voice over IP.
> $ sudo jackd -d dummy -r 8000 -p 160
> 4) Make a call to the extension created in Asterisk in step 2.  You  
> should see
> the two new jack ports become available.  In theory, they are  
> available for
> connection to any application that can use Jack.  The only thing I  
> have done so
> far is to use the "patchage" application to connect the ports  
> directly together
> to verify that the audio is flowing correctly.
> Now, to figure out how to hook up arbitrary jack ports to Pd ... if  
> anyone has
> any pointers, it would be much appreciated.  I'm still very new to  
> Pd.  :)
> --
> Russell Bryant
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"[W]e have invented the technology to eliminate scarcity, but we are  
deliberately throwing it away to benefit those who profit from  
scarcity."        -John Gilmore

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