Qtractor An Audio/MIDI multi-track sequencer
What's Qtractor ?
Qtractor is an Audio/MIDI multi-track sequencer application written
in C++ with the Qt4 framework.
Target platform is Linux, where the Jack Audio Connection Kit
(JACK) for audio, and the Advanced Linux Sound Architecture
(ALSA) for MIDI, are the main infrastructures to evolve as a fairly-featured Linux desktop audio
workstation GUI, specially dedicated to the personal home-studio.
Qtractor is free, open-source software, distributed under the terms of the
GNU General Public License (GPL)
version 2 or later.
Project page: http://sourceforge.net/projects/qtractor
Click on image to see more screenshots...
- 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, native VSTi and LV2 plug-in support.
- Unlimited number of plug-ins per track or bus.
- Plug-in presets, programs and chunk/configurations support.
- Unlimited audio effect send/return inserts per track or bus.
- Audio/MIDI clip fade-in/out (linear, quadratic, cubic).
- Audio/MIDI clip gain/volume, normalize, export.
- Audio/MIDI track and plugin parameter automation (dynamic curves,
sample&hold, linear and spline modes).
- 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.
- Unlimited location/bar markers.
- MIDI clip editor (matrix/piano roll).
- MIDI instrument definitions (a-la Cakewalk(tm) (*.ins));
SoundFont (*.sf2) and MIDI Names XML (*.midnam) files also supported.
- MIDI controller mapping/learn/assignment (mixer and plug-in parameters).
- MIDI system exclusive (SysEx) setups.
- JACK transport sync master/slave.
- JACK session support.
- NSM (Non session management) support.
- MMC control surface enabled.
- MIDI Song Position cueing support.
- Configurable keyboard shortcuts.
The software requirements for build and runtime are listed as follows:
Optional (opted-in at build time):
- libvorbis (enc, file), Ogg Vorbis audio compression
- libmad, High-quality MPEG audio decoder
- libsamplerate, The secret rabbit code, C library
for audio sample rate conversion
- librubberband, Rubber Band Audio Time Stretcher,
an audio time-stretching and pitch-shifting library
- liblo, Lightweight OSC implementation
(needed for DSSI GUI and/or NSM support)
- DSSI, An API for soft synth plugins with custom user interfaces
- VST SDK, Steinberg's Virtual Studio Technology
- LV2, Audio Plugin Standard, the extensible successor of LADSPA
- liblilv, Lightweight LV2 implementation stack
- NSM, Non Session Management
Qtractor's still in some alpha stage of development, but already
functional. The bleeding-edge development source tree is readily available
from the sourceforge's public Subversion repository.
However there has been several so called pre-releases that might be representative
of the project's shallowed milestones.
2013-10-07 - The Lima Oscar
- Adding a track now inserts it after the current one, if any;
one can also drag and move a track below the last one in the
track list (main view left pane).
- Extended Edit/Select Mode/Automation: multi-selection mode,
cut, copy, paste and delete of current track's automation
curve nodes, now reached implementation ready status.
- Another old silent bug bites the dust: changing track names
were dropping any track gain/volume and panning automation
curves when saving the session.
- A primeval processing bug has been sorted out: aux-sends to
audio output buses that just appear to be after the input
bus where they're inserted were being left muted and silent
(on a ticket follow-up by Holger Marzen, thanks).
- Fixed a sure crash bug exposed when processing of aux-send
plugins when inserted too early on audio input buses chain
(after a ticket report by Holger Marzen, thanks).
- Allow the build system to include an user specified CFLAGS
(patch by Cristian Morales Vega, thanks).
- Shift/Ctrl keyboard modifiers now set to extend current clip
selection while in main track view's Edit/Select Mode/Range,
- Main Edit/Select Mode/Automation icon retouched to look a bit
more obvious and intuitive, hopefully ;)
- Allow to change the velocities/values of the current selected
events which have the exact same onset times and hide beyhond
each other on the MIDI clip editor's pane below the main view
piano-roll (ie. the one that represents MIDI event values as a
- Fixed some problematic playback/export muting and annoying
cleanup freezing, due on audio tracks with too many clips
eg. more than hundred clip splits (hopefully fixes an issue
reported by Louigi Verona, thanks).
- LV2 UI resize feature support/control added.
- Fixed dedicated MIDI control and MIDI metronome port connection
restore conflict (thanks to jhammen catch & patch:).
- New user preference option added: reverse middle-button role to
Shift/Ctrl keyboard state, in special regard to edit-head/tail
vs. play-head positioning while on the main track and MIDI clip
editor (aka. piano-roll) views.
Previous and older pre-releases, including the change log,
are also available here.
You can browse all files available for download, including binary packages, at
Qtractor Files on SourceForge.net.
The installation procedure follows the standard for source distributions.
Once under the extracted source directory:
and optionally as root:
This procedure will end installing the following files:
Just launch prefix
/bin/qtractor and you're off (hopefully).
Note that the default installation path prefix is
Qtractor holds its settings and configuration state per user,
in a file located as
Normally, there's no need to edit this file, as it is recreated and
rewritten everytime qtractor is run.
Plenty, after all this is still alpha software ;).
Qtractor 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.
A new Qtractor quick start guide and user manual
has been updated for version 0.5.x by Seth Kenlon & Klaatu.
The older user manual for version 0.3.0 and before,
have been co-authored by James Laco Hines and Stephen Doonan.
Qtractor logo/icon is an original work of Andy Fitzsimon, borrowed from
the public domain openclipart.org gallery.
A special mention should also go to the translators of Qtractor, of course:
- Pavel Fric (cs)
- Guido Scholz (de)
- Yann Colette (fr)
- Massimo Callegari (it)
- Takashi Sakamoto (ja)
- Alexandre Prokoudine (ru)
This project has also a freecode.com entry.
( formerly freshmeat.net )
rncbc aka Rui Nuno Capela
rncbc at rncbc dot org