[Jack-Devel] Netjack - one audio source, multiple remote destinations

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DateSat, 25 May 2013 19:57:59 -0400
From Jason Cipriani <[hidden] at gmail dot com>
To[hidden] at lists dot jackaudio dot org
Follow-UpAdrian Knoth Re: [Jack-Devel] Netjack - one audio source, multiple remote destinations
I'm working on a project where we'd like to have a single central PC
(running Linux, currently Ubuntu) streaming different audio streams to
multiple other devices (Gumstix Overo, jackd 1 available, 20 devices).

On the central PC, essentially 20 instances of the same audio source
software are running, one per remote device, with the goal of streaming the
output of each to one of the remote devices (one channel per device). The
audio source software allows specification of a jack server name and a jack
port name, so it is flexible wrt jack.

So far I've been able to successfully stream audio to one device by:

  1. On device (master): jackd -d alsa ...
  2. On device (master): jack_netsource -H central_pc_ip
  3. On device (master): jack_connect netjack:capture_1 system:playback_1
  4. On PC (slave): jackd -d netone ...
  5. On PC (slave): Start audio source software.

Works great!

Using the above steps, my first attempt to streaming to multiple devices
was as follows. The main challenge is that the master plays audio, the
slave originates audio, but a slave cannot be connected to multiple masters.

  1. On device (master): Set up as above except choose a unique slave port
number per device.
  2. On PC (slave): Start one instance of jackd -d net per device,
specifying the correct port number for that device, and a unique server
name.
  3. On PC (slave): Start one instance of audio source software per device,
specifying the correct jackd server name.

This also works great *except* there seems to be a limit to the number of
jackd servers that can run (my limit is 8). So, this does not work, since I
need 20.

I'm not sure how to proceed. Some of my thoughts, all of which I'm stumped
on:

  * Can the limit to number of jackd servers be increased?
  * Can the slave be set to play audio instead of the master? If so then:
    - Control PC could be master, connected to 20 slave devices.
    - One instance of jackd on control PC, perhaps with a different jack
port per slave device.
    - Each instance of audio source software connects to appropriate jack
port on same jack server.
  * A non-jack solution? Problem is the Gumstix devices have a very limited
package database, and we're trying to stay off-the-shelf.

Version of jackd on control PC:
*jackdmp 1.9.8
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2011 Grame.
*
Version of jackd on devices:
*jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
and others.
*
I've hit my limit with research and experimentation, so I'm wondering if
anybody on this list has any recommendations.

Thank you!
Jason
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