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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!


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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