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Qtractor 0.4.2 - The Flaunty Demoness is out!

Howdy! Greatest thanks goes to Mathias Krause aka gizzmo, who contributed with the fundamental code to the new MIDI controller mapping functionality that now widens the Qtractor horizon with regard from generic control surfaces. Being the Behringer BCF2000 a notable example, control feedback is fully supported so that those fancy motorized faders, knobs and lights, actually reflect the whole mixing and editing session state. Some pre-made files are here provided for your convenience: bcx2000.qtc is to import into Qtractor (View/Controllers...) and a couple of presets goes into your BCF2000, Qtractor_Mixer_1-8.syx and Qtractor_Mixer_9-16.syx, respectively for the first and second set of eight channel/track strips.

Ah, the previous hardwired support for the JLCooper-like controls, provided by the Tascam US-224 and US-428 (via us428control), is now optional. You can have it back by just adding this file, usx2y.qtc, to the controllers map.

That's it:

Qtractor 0.4.2 (flaunty demoness) is out!

Release highlights:

  • MIDI controller mapping (mixer) (NEW)
  • Audio/MIDI multi-clip merge (NEW)
  • Multi-clip selection export (NEW)
  • Improved snap precision on drag/moving clips (FIXED)
  • and some other asorted fixes (see change-log;)


Qtractor is an audio/MIDI multi-track sequencer application, written in C++ on top of Qt Software's Qt4 framework, having JACK and ALSA as its main infrastructures and Linux as native and exclusive platform. Specially suited to the lone-wolf composer, arranger and (re)creative music-maker personal home-studio, it still hopes to evolve as a fairly featured desktop audio/MIDI workstation or at least, a prototypical part of it ;)


Project page:


Weblog (upstream support):


Qtractor is free, open-source software, distributed under the terms of the GNU General Public License (GPL) version 2 or later.


  • Multi-track audio and MIDI sequencing and recording.
  • Developed on pure Qt4 C++ application framework (no Qt3 nor KDE dependencies).
  • Uses JACK for audio and ALSA sequencer for MIDI as multimedia infrastructures.
  • Traditional multi-track tape recorder control paradigm.
  • Audio file formats support: OGG (via libvorbis), MP3 (via libmad, playback only), WAV, FLAC, AIFF and many, many more (via libsndfile).
  • Standard MIDI files support (format 0 and 1).
  • Non-destructive, non-linear editing.
  • Unlimited number of tracks per session/project.
  • Unlimited number of overlapping clips per track.
  • XML encoded session/project description files (SDI).
  • Point-and-click, multi-select, drag-and-drop interaction (drag, move, drop, cut, copy, paste, paste-repeat, delete, split, merge)
  • Unlimited undo/redo.
  • Built-in mixer and monitor controls.
  • Built-in connection patchbay control and persistence (a-la QjackCtl).
  • LADSPA, DSSI and native VSTi plug-in support.
  • Unlimited number of plug-ins per track or bus.
  • Plug-in presets, programs and chunk/configurations support.
  • Audio/MIDI clip fade-in/out (linear, quadratic, cubic).
  • Audio/MIDI clip gain/volume, normalize, export.
  • Audio clip time-stretching (WSOLA-like or via librubberband), pitch-shifting (via librubberband) and seamless sample-rate conversion (via libsamplerate).
  • Audio/MIDI track export (mix-down, merge).
  • Audio/MIDI metronome bar/beat clicks.
  • Unlimited tempo/time-signature map.
  • MIDI clip editor (matrix/piano roll).
  • MIDI instrument definitions (a-la Cakewalk(tm)).
  • MIDI controller mapping (mixer).
  • JACK transport sync master.
  • MMC control surface enabled.
  • MIDI Song Position cueing support.
  • Configurable keyboard shortcuts.


  • The MIDI clip editor (piano-roll/matrix editor), the main track view as well, have been subject to usability fixing, the most notable avoids clearing current selection as much as possible when updating view contents (eg. changing zoom levels does not reset current selection anymore).
  • MIDI tracks channel bank/program and controller stuff are now only issued when the respective bus connections have changed, seldom on every playback start.
  • MIDI controller mapping infrastructure, with file based configuration management (see View/Controllers...), is now in place, following an original contribution from gizzmo aka Mathias Krause.
  • Plugin chain buffer reset on playback start/stop is not guarded by a momentary plugin de/activation anymore.
  • Clip export may now be applied to multiple clips, sharing common refactored code and same semantics as merging of current selected clips.
  • Improved, may be just fixed yet again, audio track export synchronization and reliability.
  • Clip merge is now featured both for audio and MIDI tracks (see Edit/Clip/Merge...).
  • Improved, or better said, fixed (again) the precision of multi-clip final positioning as result of drag/move and paste operations in main track view (as in bug #2741611).
  • MIDI track program number is now listed in 1-128 range, in an attempt to be consistent with corresponding MIDI track dialog drop-down list.
  • MIDI editor snap grid lines get slight different color then regular beat divisions.
  • Reset local tempo map cursor on newer MIDI file imports in a tentative to fix incidental but random crashes.

Cheers && Enjoy!


Great work out there! I really really would like to try Qtractor and help you with some bug submission; is there any .deb package of 0.4.2 for Ubuntu?

@Rui: Wow ... I didn't know I did that much for this release *g* ... thanks ...
@Sigma: As I will compile qtractor for my system today (Ubuntu 8.04 Studio) I may be able to genereta a .deb package. But hey.. whats about this one: qtractor_0.4.2-1.rncbc.ubuntu804_i386.deb

rncbc's picture

The qtractor_0.4.2-1.rncbc.ubuntu804_i386.deb package depends on librubberband1, which is not wildly available out there. For your convenience, I've made it myself available, here:

You should only need to install the first one. The others are optional.


Hi! Big fan of your project, I'm hoping it will eventually allow me to ditch using Sonar through wine. I'm currently trying to install this version (I had an older one on my hardy install a while back), but jaunty is not playing nice with the deb file. your rubberband deb took care of that dependency, but the name of the liblo0 package was changed in synaptic after hardy. For some reason it's now called liblo0ldbl, and so your deb is unable to find the package so I can proceed with the install. Is there any chance there is a workaround to this? I'd appreciate any help you can give me, and thanks a lot for qtractor!

rncbc's picture

I'm no expert in debian packaging management so what I'm going to suggest might be outrageously wrong and still going with it without fully understanding their effect may break your whole system, so take that with extra precaution and do read the man(ual) pages first :)

So, if you're sure that liblo0ldbl is what it says, my suggestion goes like installing the qtractor.deb with the mighty force option, i.e., use:

dpkg --force-things ...


I haven't downloaded this version, but i tried the 0.4.1 and I was amazed. My compliments go to you, because you succeded in making a program that's very simple and intuitive, yet, with a few buttons, it gives you everything you need, i love it! furthermore you say it's still in "alpha" stage, but for me it worked like a charm and it never crashed! you did a great job, thank you!

Hello Rui,

Compliments for publishing such a great recording tool! But... I can't find a Jaunty 64-bit deb package anywhere. Could you maybe provide one? Thanks!



rncbc's picture

You may find that from the new (fussy doula) release:


taking care that you'll need the librubberband1 stuff:


and just in case you feel brave enough to follow development up close:


and there's also the collaterals:



Many thanks! I tried downloading qtractor_0.4.3 but unfortunately: The "qtractor_0.4.3-1.rncbc.ubuntu904_amd64.deb" file could not be found or is not available. Please select another file.

Thanks, got it now :)


rncbc's picture

It is me who have to thank you. Your support is highly appreciated.


Hello Rui, many thanks! And a new version too, awesome!
I have another totally different question though, I'd like to donate to this project, not a substantial amount, but just some money to show my gratitude) :)
What is the best way to do so? Thanks!


Hi. I like your blog. well done!

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