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Qtractor 0.4.4 - The Frisky Demivierge's in the wild!

What? No automation, yet? Yes I failed the promise once again. So what? What would you expect from this self-called über-procrastinator? As sure is one to say that this is the Year of Linux Desktop (YOLD:), I'll give you the shivers and command this one will be the year of Qtractor Automation. No kiddin' ;)

Meanwhile, this new dot-release brings you several niceties, a couple of them have been waaay longer and dustier on the all-mighty-overdue TODO list than automation is. Rejoice! or else...

Qtractor 0.4.4 (frisky demivierge) is in the wild!

Release highlights:

  • LV2 plug-in support (NEW)
  • MIDI event list view (NEW)
  • Expedite audio/MIDI clip import (NEW)
  • DSSI plug-in output control ports feedback/update (NEW)
  • JACK transport, MMC, SPP control options (NEW)
  • Self-bounce/recording (FIX)
  • Audio/MIDI drift correction (FIX)
  • Anti-glitch audio micro-fade-in/out ramp smoothing (FIX)


Project page:


Weblog (upstream support; oh wait...):


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


  • For all the DSSI plugins that have output control ports, a host feedback/update process cycle is now being finally provided: all output control ports are now marshaled to their respective GUI process, rather often and when found open/visible.
  • MIDI clip editor (aka piano-roll) snap-to-beat behavior on edit mode is now kind of more like 'filling-in-the-blanks' (as Frank Neumann et al. wishes ;)
  • Fixed MIDI clip editor mistake when reverting to initial clip length, before closing and discard changes (thanks to Frank Neumann, for spotting this one).
  • LADISH Level 1 support has been added: SIGUSR1 signal trap just makes it a shortcut to File/Save.
  • Avoid parameter value flickering, due to duplicate command invocation, most evident when changing values massively on native Linux VSTi plugin editor GUIs (thanks to a detailed report on this odd behavior, from Mike of
  • Another TODO item bites the dust: MIDI event list editor, now accessible from the MIDI clip editor menu (View/Events)
  • Last used session directory is now made current on startup only when no filename is given on the command line (solving bug #2920244).
  • Current snap-to-beat setting (time quantization) now affects the anchor event only, while dragging, moving and/or pasting multiple events over the MIDI clip editor (aka piano-roll).
  • Make anti-glitch audio clip micro fade-in/outs independent from current buffer size as much as possible.
  • Audio/MIDI engine drift correction gets really sophisticated, with the help of (now old) ALSA MIDI tempo skew facility.
  • Edit/Clip/Import... menu option is now available for expedite clip insertion from audio and MIDI file requesters.
  • Set default session directory effective to file's location.
  • Audio track/clip recording process has been target to special re-factorization across the internal audio engine process cycle, in a late attempt to get self-bounce/recording effective and working consistently for all track layouts.
  • All session related dialogs are now set to window modality, (were set to default application modality before) allowing for continued input focus and interaction on all plugin/tool windows.
  • An off-by-one nasty old bug fixed in audio clip drawing, was causing instant crashes on certain zoom levels of the main track view.
  • Graphical MIDI clip representation regarding note/pitch range is now kept as much as possible across clip edits (cut, copy, paste, drag, move, delete, etc.)
  • LV2 plug-in hosting has finally come into actual implementation; only some and the most basic LV2 plug-in features are supported at the moment; probably there's no big advantage against the old LADSPA ones; there's some support for external UIs though; also, LV2 MIDI/Event bare-bones support is included but chances are it won't build nor work right on most of the setups out there. It's a WIP host implementation anyways, as is the whole LV2 spec. for that matter ;)
  • Connections filter is now reset when widget is shown through the View/Connections main menu or toolbar button.
  • Audio bus auto-connection option is now applied when creating or updating, newer or existing buses, respectively.
  • Global configuration state is now explicitly saved/committed to disk whenever View/Options... dialog changes are applied or when a session is loaded or saved.
  • Audio ramping spin-locking makes its smooth stuff, in an attempt to reduce glitching and crackling when editing (due to its own pseudo spin-locking) and toggling playback states.
  • JACK Transport, MMC Device, and MIDI Song Position pointer (SPP) control modes are now made optional (View/Options...), allowing for discretionary configuration: None/Disabled, Slave/Input, Master/Output or Full/Duplex (default).
  • Session files may now be dragged and dropped over the main track view and get loaded for business as usual (once quietly ignored).
  • In an attempt to mitigate potential stack corruption and sudden crashes, old commented out session pseudo-locks are now back in business while executing clip editing commands (cut, paste, drag, move, insert, delete) and playback is currently rolling.
  • Adjusted first-time application window size to fit into 800x600 screen size and with reasonable initial dock-ables layout.
  • Avoid duplicate snap-to-grid effect when changing the length of MIDI clip editor events across non-zero clip offsets (after a glitch reported by Ralf Mardorf).
  • Late audio track processing optimization, suppressing all plugin, mixer and monitor pass-through activity when given track is muted, either explicitly or implicitly (ie. other track is in solo state).
  • Entering System Exclusive events (SysEx) on the MIDI clip editor (aka matrix/piano-roll widget), yet something not fully supported anyway, even though allowed in edit mode, doesn't crash the whole damn thing anymore, while saving the clip to a file.
  • Strict aliasing avoidance, with plain and demanded use of 'union', as much as to stop nagging warnings from gcc >= 4.4.1 (last seen on src/qtractorMidiEvent.h hackery).
  • Visual correct play-head position while changing zoom levels, applicable to both main track and MIDI clip editor views.

Cheers && Enjoy.


rncbc's picture

Qtractor 0.4.4 - Frisky Demivierge's in the wild!

Now linking to librubberband2 as provided on Karmic repos and fulll LV2 plugin support (nb. you might need libslv2-9 from Lucid repos).


Great work, I´m sure! Can´t wait to try it out...unfortunately may take a while to get around to compiling and testing, but am just glad the good work continues...Qtractor is my bet for the linux audio app to look out for! :D


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