[LAD] Looking for some jackd debugging help

Ethan Funk ethan at redmountainradio.com
Sun Jun 14 03:07:07 CEST 2020

Thanks.  I found autojack, and know just enough Python to make some
sense of it.  I am still confused as to where autojack is getting the
64 value.  I easily found...
                procin =
subprocess.Popen(                    ["/usr/bin/zita-a2j", "-j",
f"{ldev}-in", "-d", f"hw:{ldev}", "-r", dsr, "-p",
def_config['ZFRAME'],                     "-n", def_config['PERIOD'],
"-c", "100"], shell=False)
...which would seem to pull the -p parameter from the def_config array.
And I see that  it's default value is 512, set early on in the code.
However, I assume this value is over ridden by my saved session setting
of 128 at some point when the code gets going.  Where is the 64 coming
from? Maybe ZFRAME is set by the GUI to half frames?
In some ways Python does make life easier than C.  I can just edit the
file with a "* 2" or "* 4", log out and back in again and go.  I assume
you are part of the group of people behind this project... so thank
On Sat, 2020-06-13 at 17:12 -0700, Len Ovens wrote:
> On Sat, 13 Jun 2020, Ethan Funk wrote:
> > That leads me to a question regarding Ubuntu Studio Control, which
> > I have beenusing to manage jackd and additional audio interfaces
> > via zita-a2j. I have UbuntuStudio Control configured to use a
> > Tascam US-4x4 as the main audio interface with128 sample process
> > frames at a 48 kHz sample rate on my test machine, with thebuilt-in 
> > audio port on the motherboard as a a2j/j2a bridge. Audio to and
> > from themotherboard interface is broken up with the zita-a2j and
> > zita-j2a running aslaunched by Ubuntu Studio Control. Notably, the
> > -p run option is set to 64. If Irun zita-a2j myself with -p set
> > nice and high, to 1024 for example, I get goodclean audio, at the
> > expense of latency on that interface. That's fine for me,since I
> > still have good, low latency on the main interface. Does any one
> > knowwhere I can find the source code for Ubuntu Studio Control so I
> > can investigate afix to make this settable?
> -controls is written in python and so easy to change. You can view
> the source directly by looking at /usr/bin/autojack. Zita-ajbridge
> has the buffer to 1/2 that of jack... but that is proving to be a
> problem in some cases. Internal should be at least 128 and hdmi
> should be 4096. The git repo is 
> https://github.com/ovenwerks id="-x-evo-selection-start-marker">/studio-controls (it has been "unbranded" so other distros can feel free to use it)
> This is a relatively new project and so is very much not bug free.
> Being able to directly set buffer size for each device used sounds
> very much like a reasonable feature request. (also a feature that has
> been thought of before)
> Be aware that autojack runs from session start and because of the way
> some DEs use systemd/logind to start sessions... the session never
> really ends so a reboot or a killall autojack may be needed to see
> how changes do. I would suggest running autojack in a terminal while
> testing new code so that you have access to terminal output. once you
> have finished with the code running studio-controls should restart it
> in the background again if you have closed the terminal.
> --Len Ovenswww.ovenwerks.net
> _______________________________________________Linux-audio-dev
> mailing listLinux-audio-dev at lists.linuxaudio.org
> https://lists.linuxaudio.org/listinfo/linux-audio-dev
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