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Qtractor 0.4.1 - Funky Dominatrix unleashed!

There are bugs which are resilient. One is never sure whether squashing one doesn't let a plethora of lurking others get loose, like one's skeleton in the closet falling apart. Paraphrasing Linus' Law, after ESR: given enough eardrums all bugs are shallow. Thanks to all the brave souls who keep harnessing the toy to the bone, some of those nasties could be whipped off. At least for the time being ;)

Trivially speaking, this dot-release marks the 4th anniversary of Qtractor as an active/personal project and, putting numerology to the side, it is being released on this April, 4th (04/04). But then, I do confess, this was just reckoned as an accidental after-thought, as everything in numerology, I guess :)

Although only one developer is still responsible for 99% of the code (that's me!:), there's some outsourcing (kind of) shaping and already pending in its early stages: MIDI event list editing; Windows native VST plugin support, much in the lines of FST/WINE, as in Ardour, perhaps; a new logo and/or splash-screen design is also under this way. Keep in mind that all translations will be asked only after the end of the current alpha phase, whenever it would be an end to it :P

Most importantly, there's serious help being needed on drafting the user manual. The current one available is getting outrageously outdated, ever since the 0.2 situation. It's already getting tough to play catch up. And everyone knows about developer(s) not feeling like doing documentation in the first place. Move on. The more participation the better.

In general, if you ever feel like, please pick up your favorite line on the ever still TODO list and do step in. You'll be more than welcome: eardrums, which usually come in pairs, just like eyeballs do, are pretty wanted!

So dress up your black leather and vinyl, put up the spiky collars and whip it, whip it good B)

Here we go:

Qtractor 0.4.1 (funky dominatrix) unleashed!

Release highlights:

  • MIDI editor snap grid. (NEW)
  • Multi-clip selection normalize and quantize (NEW)
  • Audio export & sample-rate conversion (FIXED)
  • MIDI & audio playback sync (FIXED)
  • SSE optimization enabled (FIXED)

and a few more fixes and same lurking bugs ;)

Same old intro/description:

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)
  • 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))
  • JACK transport sync master.
  • MMC control surface enabled.
  • MIDI Song Position cueing support.
  • Configurable keyboard shortcuts.

Change log:

  • MIDI editor command item execution order has been fixed, correcting the redo/undo adjustment of overlapping note events (probably fixing bug #2723861).
  • MIDI clip editor (aka. piano-roll/matrix editor) sees one of its most wanted features introduced: visual snap grid, now accessible through View/Snap/Grid option toggle.
  • Actual non-zero session length gets back to status bar of main application window.
  • One potential buffer-overflow/memory-corruption crash bug has been fixed, long due on most audio (down) sample-rate conversions and affecting audio export in particular.
  • MIDI track/channel patch information, ie. bank-select and program-change events, are now being properly set on MIDI track/clip export.
  • SSE optimization is back in town after being mysteriously disabled since its dawn :/
  • Looping and punch-recording now actively mutual exclusive states: setting either one unsets the other off and vice-versa. Also, punch-in/out is now made an undo-able command.
  • Moving tracks, any track, up or down, were leaving MIDI playback and meter monitoring completely out-of-sync, now fixed.
  • Automatic crash-dump reports, debugger stack-traces (gdb), back-traces, whatever, are being introduced as a brand new configure option (--enable-stacktrace) and default enabled on debug build targets (--enable-debug).
  • Audio/MIDI drift correction is now progressive, taking a least significant differential approach, on every read-ahead cycle and swallowed on loop turnarounds, as before.
  • Improved Edit/Clip/Normalize and Quantize commands, now affecting the whole extended multi-clip selection.
  • Playback is now being temporarily suspended while either transport rewind or fast-forward rolling is engaged.
  • A bad and shame-on-me bug was fixed: this was hideously affecting any track/clip playback synchronization, most noticeable after toggling solo/mute track states while playback is rolling and skipping the play-head backward over more than one clip under the same track.
  • A floating-rectangle flip that showed while dragging new files beyond the left of main track view is now gone.
  • MIDI note event truncation on both track and clip export has been fixed.

Cheers && Enjoy!