JACK Audio Connection Kit - Qt GUI Interface

[Intro] [Screenshots] [Requirements] [Downloads] [CVS] [Installation] [Configuration] [Bugs] [Support] [Acknowledgements]

What's QjackCtl ?

QjackCtl is a simple Qt application to control the JACK sound server daemon, specific for the Linux Audio Desktop infrastructure.

Written in C++ around the Qt4 toolkit for X11, most exclusively using Qt Designer.

Provides a simple GUI dialog for setting several JACK daemon parameters, which are properly saved between sessions, and a way control of the status of the audio server daemon. With time, this primordial interface has become richer by including a enhanced patchbay and connection control features.

License: GNU General Public License (GPL)

Sourceforge project page: http://sourceforge.net/projects/qjackctl

Screenshots

Click on image to see more screenshots...

Requirements

The software requirements for build and runtime are listed as follows:

Mandatory:

• Qt 4 (core, gui, xml), C++ class library and tools for crossplatform development and internationalization
  http://www.trolltech.org/products/qt/
• JACK Audio Connection Kit
  http://jackaudio.org/

Optional (opted-in at build time):

• ALSA, Advanced Linux Sound Architecture
  http://www.alsa-project.org/

Downloads

Latest release

2007-12-20 Patchbay heads-up with season greetings.
qjackctl-0.3.2.tar.gz

• Patchbay port matching has been slightly extended, this time allowing for the multiple or as many-to-many connections between socket plugs, provided these are specified in proper regex form (after a patch proposed by Dave Moore, thanks).
• A new option to start the program minimized when the system tray icon is enabled, is now available from Setup/Misc/Start minimized to system tray (as kindly suggested by Marc-Olivier Barre).
• Regression from QSystemTrayIcon (Qt4 >= 4.2) implementation, at least on X11 environments: while the main application widget was minimized to the system-tray, closing any other top-level widget was causing the immediate and unexpected application shutdown.
• Some portaudio backend settings are now being enabled, specially suited for the jackdmp flavouring.
• Server mode display blinking, usually shown as the RT indicator, is now an option (Setup/Display/Blink server mode indicator when started).
• Tool/child windows position and size preservation fixed.
• The connections/patchbay auto-refresh option has been finally removed due to several user requests, although deprecated for quite some time now it has been the probable cause of some periodic xrun occurrences due to graph-locking in jackd (while making Geoff Beasley angry in the process:).
• Messages line limit was not being checked, now honored.
• Simple as it could ever be, the build executive summary report is now given on configure.
• Patchbay snapshot got its socket and port ordering back.
• ALSA Sequencer support is now an optional feature on setup, preventing the annoying "MIDI patchbay will be not available" warning message, ruining window placement on Linux systems where the snd-midi-seq kernel module is not loaded or not favorable (eg. OSS) at startup (by request from Jussi Laako).
• Get configure to try and detect the correct qmake location and insert it the search order, so let the qt4 tools take precedence when --with-qt option is given and older qt3 ones coexist and are found located ahead in the PATH.
• The connections widget is now being properly refreshed, due to some quirk in the QTreeWidget which was preventing some items, specially the expanded ones, to disappear in the void. Meanwhile, with a hand from Stephane Letz, the client/port lookup method was changed to prevent duplicated, missing entries or worse, crashes due to weird behaved windows applications.
• The xrun count stats can now be reset simply by middle clicking on the systray icon or the main window's display area (thanks to patch sent by Dominic Sacré).
• An improved version of the "shiny" background image was issued. The original somehow looked like two different images put together, probably most apparent on a bright TFT screen (by Dominic Sacré).
• A warning is now being issued, asking whether one wants to remove a corresponding Patchbay connection, when client/ports are being disconnected over the Connections window, thus avoiding automatic reconnection annoyance due to normal active Patchbay behavior.
• The infamous "Keep child windows always on top" global option is now supposed to behave a little better when disabled, layering child windows as naturally as far the window manager dictates.
• Input/Output Channel setting is now allowed to be greater than 32; the special default text is now displayed, also on Input/Output Latency and Priority settings spin-boxes.
• Andreas Persson just sent a patch that makes it possible to compile and run qjackctl with Qt version 4.1. Applied without hesitation, thanks.

Previous and older releases, including the change log, are also available here. You may also check out from the latest bleeding edge development source tree, using CVS.

Installation

The installation procedure follows the standard for source distributions. In the extracted source directory, just do:

./configure [--prefix=prefix]
make

and optionally as root:

make install

This procedure will end installing the following couple of files:

• prefix/bin/qjackctl
• prefix/share/pixmaps/qjackctl.png
• prefix/share/applications/qjackctl.desktop

Just launch prefix/bin/qjackctl and you're off (hopefully). Note that the default installation path prefix is /usr/local .

Configuration

Qjackctl holds its settings and configuration state per user, in a file located as $HOME/.config/rncbc.org/QjackCtl.conf. Normally, there's no need to edit this file, as it is recreated and rewritten everytime qjackctl is run.

Bugs

Probably plenty still, but qjackctl it's now considered on beta stage already. It has been locally tested since JACK release 0.98.0, on SuSE 9.1, Mandrake 10.0 and Fedora Core 1, with custom 2.4 kernels with low-latency, preemptible and capabilities enabling patches. As for 2.6 kernels, the capabilities patch may also apply but the emergence of the Realtime Linux Security Module (LSM) and Ingo Molnar's Realtime Preemption kernel patch it's being now recommended for your taking benefit of the realtime and low-latency audio pleasure JACK can give.

Support

Qjackctl is open source free software. For bug reports, feature requests, discussion forums, mailling lists, or any other matter related to the development of this piece of software, please use the Sourceforge project page.

You can also find timely and closer contact information on my personal web site.

Acknowledgements

Qjackctl's user interface primordial layout (and the whole idea for that matter) was partially borrowed from Lawrie Abbott's jacko project, which was just taken from wxWindow/Python into the Qt/C++ arena.

Since 2003-08-06, qjackctl has been included in the awesome Planet CCRMA software collection. Thanks a lot Fernando!

This project has also a freshmeat.net entry.

Dated from 2004-06-08, an online article written by no one else but Dave Phillips, has been published on Linux Journal, introducing you to Qjackctl and also QSynth. Please have a read:

At the Sounding Edge: Using QSynth and QJackCtl.

It's not on every regular day that you get to see one piece of the trade pointing two of your creations right in the title, is it?

Thanks Dave! You rule!

Here are some people who helped this project in one way or another, and in fair and strict alphabetic order:

Thanks to you all.

rncbc aka Rui Nuno Capela
rncbc at rncbc dot org