Qtractor An Audio/MIDI multi-track sequencer

What's Qtractor ?

Qtractor is an Audio/MIDI multi-track sequencer application written in C++ with the Qt 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: https://sourceforge.net/projects/qtractor

Weblog: https://www.rncbc.org

Wiki: https://sourceforge.net/p/qtractor/wiki/

• User Manual & How-To's:
  qtractor-manual-and-howtos.epub
  qtractor-manual-and-howtos.pdf

Screenshots

Click on image to see more screenshots...

Features

• Multi-track audio and MIDI sequencing and recording.
• Developed on the Qt C++ application an UI framework.
• 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, freeze)
• Unlimited undo/redo.
• Built-in mixer and monitor controls.
• Built-in connection patchbay control and persistence (a-la QjackCtl).
• LADSPA, DSSI, native VST(2), VST3, LV2 and CLAP plug-ins support.
• Unlimited number of plug-ins per track or bus.
• Plug-in presets, programs and chunk/configurations support, including native VST FXB/FXP file support.
• Unlimited audio/MIDI effect send/return inserts per track or bus.
• Loop-recording/takes.
• Audio/MIDI clip fade-in/out, cross-fade (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, render, 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 Clock, Song Position Pointer (SPP) support.
• Configurable PC-keyboard and MIDI controller shortcuts.

Requirements

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

Mandatory:

• Qt framework (core, gui, xml), C++ class library and tools for cross-platform application and UI development
  https://qt.io/
• JACK Audio Connection Kit
  https://jackaudio.org/
• ALSA, Advanced Linux Sound Architecture
  https://www.alsa-project.org/
• libsndfile, C library for reading and writing files containing sampled sound
  http://www.mega-nerd.com/libsndfile/
• LADSPA, Linux Audio Developer's Simple Plugin API
  http://www.ladspa.org/

Optional (opted-in at build time):

• libvorbis (enc, file), Ogg Vorbis audio compression
  https://xiph.org/vorbis/
• libmad, High-quality MPEG audio decoder
  https://www.underbit.com/products/mad/
• libsamplerate, The secret rabbit code, C library for audio sample rate conversion
  http://www.mega-nerd.com/SRC/
• librubberband, Rubber Band Audio Time Stretcher,
  an audio time-stretching and pitch-shifting library
  https://breakfastquay.com/rubberband/
• liblo, Lightweight OSC implementation
  (needed for DSSI GUI and/or NSM support)
  http://liblo.sourceforge.net/
• DSSI, An API for soft synth plugins with custom user interfaces
  http://dssi.sourceforge.net/
• VST SDK, Steinberg's Virtual Studio Technology
  https://www.steinberg.net/
• LV2, Audio Plugin Standard, the extensible successor of LADSPA
  http://lv2plug.in/
• liblilv, Lightweight LV2 implementation stack
  https://drobilla.net/software/lilv/
  https://drobilla.net/software/sratom/
  https://drobilla.net/software/sord/
  https://drobilla.net/software/serd/
• libsuil, Lightweight C library for loading and wrapping LV2 plugin UIs
  https://drobilla.net/software/suil/
• libaubio, a library for real time audio labelling
  https://aubio.org

Downloads

Qtractor's already in some kind of beta stage of development and hence fully functional. Though, the bleeding-edge development source tree is readily available from the sourceforge's public Git repository.

Latest release

2022-12-30 - An End-of-Year'22 Release.
qtractor-0.9.30.tar.gz

• Plugin latency/delay compensation now in effect immediately after changing track option (cf. Track/Properties... /Plugins/Latency compensation).
• Shade-off regions not-in-view from the thumb-views.
• Improved MIDI queue time drift correction resilience and stability against in-flight tempo changes.
• The main real-time process cycle now runs on uniform block-sizes, in strides of 64 frames per period, meaning a higher resolution automation, independent of buffer-size.
• The internal main MIDI engine gets its ALSA sequencer queue to a higher resolution (PPQN aka ticks-per-beat) and not subordinated to the current session's anymore.
• Although being deprecated to use, JACK Session support is hopefuly fixed, once again.
• Better discriminate CLAP Plug-in specific note events and strict MIDI dialect event processing.

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.

Installation

Unpack the tarball and in the extracted source directory:

cmake [-DCMAKE_INSTALL_PREFIX=prefix] -B build

cmake --build build [--parallel Njobs]

and optionally as root:

[sudo] cmake --install build

Note that the default installation path prefix is /usr/local .

Configuration

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

Bugs

Probably plenty still, Qtractor maybe considered on beta stage already.

Support

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.

Acknowledgements

The dated Qtractor quick start guide and user manual for version 0.5.x has been authored 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:

And, of course, last but not least, to all the past, present and future contributors of the Qtractor Wiki.

Thank you all.

Enjoy,