Matt Flax | 21 Aug 05:13 2014

Sample rate reports incorrectly

Hi there,

I have an alsa driver which has a sample rate of 18750 Hz.
There are stereo 16 bit words, which means that the I2S bit clock rate 
is 600 kHz.
I have attached an image of the I2S bus which shows the bit clock rate 
is 600 kHz and also shows the LR clock line.

This proves to me that the ALSA samplerate is correct at 18750 Hz.
However when I ask Jack for the sample rate, it reports :

# jack_samplerate

Here is how I start Jack :
jackd -d alsa -s -i 2 -o 2 -r 18750

I am wondering if anyone is aware of this problem ?

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Adrian Knoth | 4 Aug 23:04 2014

Intro article on AES67 clocks


Let me forward you an article that was just posted to the AES67 mailing
list. If you consider to implement AES67 one day, this article gives you
a brief introduction to the clocks involved.

If you're already familiar with PTP (IEEE 1588), there's no use in
reading it, since AES67 of course uses PTP (like Ethernet/AVB).

For a real-world implementation, one can assume that PTP is taken care
of by linuxptp, one of the way too many competing PTP implementations.
To the best of my knowledge, linuxptp is really the way forward, all
other implementations are considered obsolete, at least on mainstream

Without further ado, here's the article:



mail: adi <at>	PGP/GPG: key via keyserver
Bektur | 30 Jul 15:50 2014

Streaming more than 2 channel audio through jack?

Hello everyone,

I have a simple setup, where a Pure Data patch (or in fact any jack-compatible sound source) streams 2 or more
channel audio from OSX / linux machine to iOS clients.

My problem is that I need to wirelessly route each channel to each of the clients (where 1 client receives
only 1 channel). Is it possible to do via jack? For instance, something like an iOS wrapper for netjack or
jacktrip would have been perfect, but as far as I know they are only OSX/linux compatible.

Alternatively, is it possible to setup a jack-compatible streaming server with multiple audio streams,
and get a mounting point for each channel separately?

Thanks in advance,
Matt Flax | 22 Jul 03:08 2014

filtering for jack net clients

Hi there,

Is there a way to detect whether a server's client is a net client ?

One possibility is to find clients with ports named '*slave*', however 
what if a local client (non-net client) names its ports with slave in 
their names ?

Stéphane LETZ | 20 Jul 15:46 2014

Jack 1.9.10 available for Linux, OSX, Windows

What is new : 

- More robust code in JackPortAudioDriver to handle buffer size change and backend switching. 
- Fix bus error on ARM platforms. 
- Dynamically scan and print backend and internal names in jackd. 
- CoreMIDI driver fixes. Rework NetJack2 code (OPUS codec on OSX, latency management, libjacknet code). 
- Correct auto-connect for audioadapter. 
- Add IIO driver. 
- Merge of Nedko no-self-connect branch. 
- Fix freewheel mode. 
- JackServer::SwitchMaster now correctly notify buffer_size and sample_rate changes,
cleanup/improvements in JackNetDriver. 
- Tim Mayberry : Add support for building with mingw compiler. 
- Merge of Kim Jeong Yeon Android branch. 
- Partial port of metadata API.

Download here:

김정연 | 19 Jul 09:20 2014

Re: Jack-Devel Digest, Vol 97, Issue 7

Dear all,

Build JACK2 1.9.10 rc2 and works fine on android's 4.4 platform(emulator).


2014-07-19 7:06 GMT+09:00  <jack-devel-request <at>>:
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>    1. JACK2 1.9.10 rc2 package to test (St?phane LETZ)
> ----------------------------------------------------------------------
(Continue reading)

Stéphane LETZ | 18 Jul 14:29 2014

JACK2 1.9.10 rc2 package to test

Here :

Thanks for testing and reporting.

Holger Marzen | 13 Jul 15:05 2014

Hook for master volume

Hi all,

a master volume fader is missing in JACK. Some audio interfaces don't
offer a volume knob. Many clients automatically connect to
system/playback, some only when playing (Clementine audio player).

What's needed is a hook within system where a master volume fader can be

Paul Davis | 8 Jul 18:01 2014

[jackaudio/jack1] efd479: Patch from Fons Adriaensen to improve validity/usa...

  Branch: refs/heads/master
  Commit: efd4794001db845433a1eff175256fc9a34f4a79
  Author: Paul Davis <paul <at>>
  Date:   2014-07-08 (Tue, 08 Jul 2014)

  Changed paths:
    M jackd/engine.c

  Log Message:
  Patch from Fons Adriaensen to improve validity/usability of jack_frame_time()

 ensures that frame time will reflect any
discontinuity in processing (xrun or skipped cycles). It also cleans up
the code related to maintaining the DLL and frame time a bit, all of it
is now together in jack_run_cycle() and the logic behind it is easy to

The 'delayed_usecs' argument to jack_run_cycle() is now probably
redundant, the value computed locally (the 'dus' variable) is in
all cases more accurate than what the backend can provide.

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(Continue reading)

Stéphane Letz | 3 Jul 17:03 2014

Re: latest version of jack 1.9.10 from 2014 does not show midi devices

Updated versions that should solve the problem:

Please test and reports.


Le 3 juil. 2014 à 16:22, chaseology <at> a écrit :

> Hi Stephane , I am a user of win version of 64 bit jack audio. 1.9.10 from 2013 beta version.  The latest
version of 1.9.10 / 2014 version is lower is file size and does not show the midi devices when using the -X
winmme command in portaudio.  The 2013 version of 1.9.10 does work fine by showing midi devices in any jack
audio connection bay.  I contacted Filipe Coelho, who has windows version of his CARL and CATIA connection
bay too and he said i should contact you with my findings.  I re-installed the 2013 version of 1.9.10 for
64bit/jack for windows, and the midi devices showed up again just fine.  I hope this helps fix the current
version of 1.9.10 to show the midi devices.  I have screen shots if that would be helpful.  thanks chase
> _____________________________________
> Sent from
Stéphane Letz | 3 Jul 15:05 2014

JACK2 1.9.10 rc1 package to test

Here :

Thanks for testing and reporting.