Linux-audio-dev

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7520 discussions

QTractor: QThreads: Not realtime on Linux without root?

by termtech

Hi list. Hope Rui gets this... I have a puzzling technical question, involving QTractor. I have been looking very closely at how Qt's class QThread works. Actually, it doesn't. On Linux. As a normal user. A long investigation into its source code and ultimately some test programs, shows that on Linux it ignores what priority you attempt to start it with, if running with normal user privileges. In Qt's qtbase/src/corelib/thread/qthread_unix.cpp: void QThread::start(Priority priority) { ... pthread_attr_t attr; pthread_attr_init(&attr); ... } This code in Qt shows it initializes with default attributes which have scheduling 'other' and thus the range of priority levels is ZERO and thus QThread is lying about being at QThread::TimeCriticalPriority for example - it is NOT, it stored your requested level but did not actually set it. I just finished examining the following programs using 'htop' plus a custom program to ask what each's scheduling policy is, using pthread_attr_getschedpolicy(): (With Jack running realtime etc. etc...) a) MusE : Two threads running FIFO policy (policy = '1'). Good, expected. MusE directly uses pthreads, and set policies and levels. I assume since I'm in the audio group with good rt limits, some help is going on, 'cause I ain't runnin' as root. b) QTractor : NO threads running FIFO (all policies = '0'). Bad? Unexpected? QTractor uses a few different QThreads with various priority settings including one requesting TimeCriticalPriority. Seem's it's not happening? c) Qt5Creator test program using QThread set to TimeCriticalPriority: Bad - thread has policy = '0'. The Mixxx project found the exact same thing: https://www.mixxx.org/wiki/doku.php/performance_improvements "RJ discovered that Mixxx's requests for real-time priority on this thread are having no effect. Running as a regular user on Linux shows that the priority range is from 0 to 0, and as root from 1 to 99, but it is set to 1 (the lowest) by default. However, calling setPriority(QThread::TimeCriticalPriority) (while running as root) does result in priority escalation. " A further look at the ticket shows they had to go with pthreads directly. What are your thoughts on this? Am I doing something wrong? Is QTractor really running realtime or not? After seeing the source and fooling with this, I'm disliking QThread. Before creating a QThread, I tried to elevate using seteuid, setegid and so on, and tried elevating to group 'audio'. Permissions denied, of course. Thanks. Tim. The MusE project.

8 years, 11 months

OpenAV Release Spree, Dec 2016

by Harry van Haaren

Hey All! OpenAV has just pushed releases for Luppp, ArtyFX, Fabla, and Sorcer! Release Video: https://youtu.be/s07wNn9Xc7s But what's more, there's now an OpenAV Manual: detailed and useful information about all of the OpenAV projects, and what features they can do for you: http://openavproductions.com/doc/ Short changelogs: LUPPP: - JACK FX Sends per track - Fixes for most (all? ;) known bugs, including: -- timing issues with clips drifing out of sync fixed -- audio fader volume not totally silencing output fixed - More controller scripts: Launchpad S, APC Mini, APCKey 25 - UI improvements - Documentation at http://openavproductions.com/doc/luppp.html ArtyFX - 1st release based on AVTK - New look-and-feel, same awesome DSP / presets - No longer depends on NTK - Documentation at http://openavproductions.com/doc/artyfx.html Fabla - Documentation at http://openavproductions.com/doc/fabla.html - Look and feel upgrade for consistency Sorcer - Look and feel for consistency - Documentation at http://openavproductions.com/doc/sorcer.html In all - quite a lot of changes! Releases available from the OpenAV Github project page: https://github.com/openAVproductions Packagers, on-your-marks, get-set, take it easy for the holidays, but package in the new year if you want to :) Special shout out to Gerald Mwangi (JimsonDrift) and George Krause for thier pull-requests and contributions to OpenAV! Happy holidays & new year ya'll :) Cheers, -Harry from OpenAV -- http://www.openavproductions.com

9 years

LAC2017: Call for Papers / Posters / Workshops / Speed Geeking / Music / Multimedia Installations

by Laurent Pottier

====== Apologies if you receive multiple copies of this document ========= LAC2017: Call for Papers / Posters / Workshops / Speed Geeking / Music / Multimedia Installations Name: LINUX AUDIO CONFERENCE 2017 (LAC2017) URL: https://lac2017.univ-st-etienne.fr/ Dates: May 18-21, 2017 Location: Saint-Etienne University, FRANCE ======== LAC 2017 – Linux Audio Conference ======== Jean Monnet University - Saint-Etienne / 18-21 May, 2017 1.Call for Papers / Posters / Workshops/ Speed Geeking 2.Call for Music / Multimedia Installations == 1. Call for Papers / Posters / Workshops / Speed Geeking == Deadline for submission: Friday, February 10, 2017 (23:59 UTC) Online (only) submission on https://lac2017.sciencesconf.org/ LAC2017 invites submissions of papers, posters and workshops addressing all areas of audio processing based on Linux and open source software. All submissions and presentations are in English. Submissions can focus on technical, artistic or scientific issues and can target developers or users. This includes (but is not limited to) the following categories: Audio and Music Languages Audio Hardware Support Audio Plugins Realtime Kernel and Linux Distributions Drivers, System and Sound Architecture Education and E-Learning Games Interactive Art Interface Design Live Coding Live Performance Media Art MIDI,OSC... Mobile Audio Music Production Music Production Tools Networked Audio Physical Computing Projects Realized using Linux Audio Signal Processing and Sound Synthesis Sound Spatialisation Standards and Protocols Video . . . == PAPERS == Papers should be written and presented in English. The length of the talks is 25 minutes followed by 5 minutes discussion. The length of the paper is 4 to 8 pages, with up to 5 keywords, and an abstract of 50 to 100 words. The abstract will be published on the conference website once the paper has been accepted. The full paper will be available on the website during and after the conference. All papers are peer reviewed by a committee of experts from different disciplines. The reviewers may suggest improvements to the author(s), or require changes in order to accept the submission. The duration of the presentation is 25 minutes followed by 5 minutes discussion. == POSTERS == The poster presentation should be 1 page, with up to 5 keywords and an abstract of 30 to 60 words. The abstract will be published on the conference website once the poster has been accepted. All posters are peer reviewed by a committee of experts in different disciplines. The reviewers may suggest improvements to the author(s), or require changes in order for the poster to be accepted. == WORKSHOPS == The workshop presentation (max duration of 2h) should be 1 page, with up to 5 keywords, and an abstract of 30 to 60 words to be published on the conference website. Submit a brief description of the workshop including URL (if available). == SPEED GEEKING == This new session aims to create links and collaborations between developers. Are you running an open source project? Come and tell the community in 3mn and 1 slide on your project and share your experience. You start a new project, come and explain your projects in 3 min. and 1 slide and recruit developers. Are you a developer eager to participate in an exciting open source project? Come and follow the SpeedGeeking session to discover the project(s) in which you want to invest your time. Submit a brief description of the project including URL (if available), and one presentation slide. == How to submit? == • The deadline for papers, posters, workshops and speed geeking submission is Friday, February 10, 2017, 23:59 UTC. • Do not send proposal via email instead please use the paper upload form in our conference management system. • The required file format is PDF, formatted for A4 paper. Authors should use the templates for paper formatting available on the download page of the conference website. • Authors of papers selected to be included in the printed conference proceedings may also have to supply supplemental material like illustrations needed to layout the printed proceedings separately. Please notify us if you need a special technical setup for your presentation. The standard setup will be: • microphone or head set • projector with XVGA input (min. resolution 1024 × 768) • stereo playback with mini jack input Also, if you are not able to bring your laptop along with you, please notify us in advance. == Important Dates == • Deadline for submissions: February 10, 2017 • Acceptance notification: March 10, 2017 • Final deadline for 'camera ready' paper: April 10, 2017 • Author registration deadline: April 20, 2017 • Final program: May 1, 2017 • LAC 2017 conference: May, 18-21, 2017 == 2. Call for Music / Multimedia Installations == Deadline for submission: Tuesday, February 10, 2017 (23:59 UTC) Online (only) submission on https://lac2017.sciencesconf.org/ LAC2017 invites also submissions of Electroacoustic Works and Multimedia Installation. A jury will select the compositions and installations to be included in the conference program according to artistic merit and technical feasibility. Please be prepared to perform your work yourself and make sure that you have all resources needed to perform your piece at your disposal (e.g. instruments, props, other performers, etc.). Unfortunately, LAC 2017 cannot pay a fee neither for you nor for any additional performers, and LAC 2017 cannot organize or pay for travel or accommodation neither of you nor of any additional performers. Electroacoustic Works and Multimedia Installation can address all areas of digital audio and audiovisual art. This includes (but is not limited to) the following categories: • Acoustic Music • Acousmatic Music • Electronic Music • Mixed Music • Sound installation • Interactive art • Audiovisual installation • Game in art • Web and connected art • New interfaces All submissions are peer reviewed by a committee of experts in music and arts. == How to submit? == • The deadline for Music and Multimedia Installations submission is Tuesday, February 10, 2017, 23:59 UTC. • Do not send files via email instead please use the file upload form in our conference management system. • The required file format is PDF, formatted for A4 paper. It includes: - registration form available on the download page of the conference website; - technical rider of the work; - video or audio link to the project; - an artbook. Important Dates • Deadline for submissions: February 10, 2017 • Acceptance notification: March 10, 2017 • Artist and Musician registration deadline: April 20, 2017 • Final program: May 1, 2017 • LAC 2017 conference: May, 18-21, 2017 Please visit conference website: https://lac2017.univ-st-etienne.fr/, for details. We are sure that you will have a wonderful experience of visiting Saint-Etienne during the LAC 2017. We look forward to welcoming you in FRANCE in 2017! Laurent Pottier ------------------------------- Email: lac(a)linuxaudio.org WWW: https://lac2017.univ-st-etienne.fr/ -- ******************************************** Université Jean Monnet CIEREC - EA3068 35, rue du 11 novembre 42023 Saint-Etienne Cedex 02 - France port. : +33(0)6 21 66 28 76 tel : +33(0)4 77 42 16 61 fax : +33(0)4 77 42 16 84 laurent.pottier(a)univ-st-etienne.fr ********************************************

9 years

[LAA] [LAU] Guitarix 0.35.2 released

by Hermann Meyer

The Guitarix developers proudly present Guitarix release 0.35.2 Guitarix is a tube amplifier simulation for jack (Linux), with an additional mono and a stereo effect rack. Guitarix includes a large list of plugins[*] and support LADSPA / LV2 plugs as well. The guitarix engine is designed for LIVE usage, and feature ultra fast, glitch and click free preset switching and is full Midi and/or remote controllable (the Web UI is not included in the distributed tar ball). This release mainly fix a build issue in Debian #839354 and ARCH Beside that, the changes are: * add stereo cabinet plugin * fix bypass insert jack port with midi CC * add menu option to set a midi controller for engine bypass * add scroll wheel support to status images * switch to use glib-compile-resources instead gdk-pixbuf-csource to include images into libgxw. * Fix Preset switching issue in lv2 amps and cabinet * disable midi control for un-loaded plugs * add check if LV2 ports are valid * fix bug #34 Note that a couple of new additional guitar related plugs in LV2 format been available on github now. They all work very well in guitarix. Check them out here: https://github.com/brummer10?tab=repositories Please refer to our project page for more information: http://guitarix.org Download Site: http://sourceforge.net/projects/guitarix/ Forum: http://guitarix.sourceforge.net/forum/ Please consider visiting our forum or leaving a message on guitarix-developer(a)lists.sourceforge.net <mailto:guitarix-developer@lists.sourceforge.net> regards hermann

9 years

Job opportunity Linux audio/C++ in Oldenburg, Germany

by Giso Grimm

Dear Linux Audio community, please find below a link to a job opportunity in Oldenburg, Germany: http://www.hoertech.de/images/hoertech/pdf/Stellenanzeigen/16-11-28_Stellen… The work is mainly development in C++ for the Master Hearing Aid, which we presented back in 2009 at the LAC in Parma (http://lac.linuxaudio.org/2009/cdm/Friday/07_Grimm/index.html), and which will become open source within the next months. The job position is at a small company in a team of developers, with close collaboration with the university of Oldenburg. For details, please see the link above. Best regards, Giso

9 years

[slghtly OT] Searching for c++ mailinglist

by J. C.

Hey hey, I was looking for a general c++ mailinglist for a while now, but could only find internet based forums. Does anyone ehre know a good, old mailinglist? It doesn't have to be restricted to c++ only. Sorry, for the sort-of OT, but in a way it's on-topic, too. :) Best wishes, Jeanette -------- When you need someone, you just turn around and I will be there <3

9 years

Re: [LAD] ALSA Sequencer timestamp on event without

by Jeff McClintock

>> The problem is the latency on receiving BLE packets. The timestamp the > device sends and the "receiver's clock" (ALSA Seq) will very quickly > get out-of-sync, causing this timestamp to be invalid. As the protocol requires sender and receiver to both maintain "clocks" which are synced (no doubt with some allowance for drift and jitter), then in this example it appears it is the sender that needs fixing. > Thus we need somehow to set the event timestamp to any arbitrary value. Is this fixing the issue, or breaking the standard? Jeff McClintock

9 years

ALSA Sequencer timestamp on event without scheduling

by Felipe Ferreri Tonello

Hello all, I have a question. I would like to send sequencer events without scheduling but with a timestamp information associated with. Is that possible? Thanks, Felipe

9 years

[ANN] Qtractor 0.8.0 - The Snobbiest Graviton is out!

by Rui Nuno Capela

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hello there! This might come as an end to a long cycle indeed, really approaching a final and last milestone, whatever... But one thing is for sure: besides the prodigal but (pun, somewhat, not intended:)), this wraps up the so called Qstuff* Fall'16 release business deal [7][8]. Qtractor 0.8.0 (snobbiest graviton) is out! And the release highlights are: * Auto-backward location marker (NEW) * Clip selection edge adjustment (NEW) * Improved audio clip zoom-in resolution (NEW) * Clip selection resilience (FIX) * MIDI (N)RPN running status (FIX) And the band plays on... Maybe you can further decrypt the fresh juice from the change-log below -- or rather never mind though and go for the grabs already ;). Qtractor [1] is an audio/MIDI multi-track sequencer application written in C++ with the Qt framework [2]. Target platform is Linux, where the Jack Audio Connection Kit (JACK [3]) for audio and the Advanced Linux Sound Architecture (ALSA [4]) for MIDI are the main infrastructures to evolve as a fairly-featured Linux desktop audio workstation GUI, specially dedicated to the personal home-studio. Website: http://qtractor.sourceforge.net Project page: http://sourceforge.net/projects/qtractor Downloads: http://sourceforge.net/projects/qtractor/files - - source tarball: http://download.sf.net/qtractor/qtractor-0.8.0.tar.gz - - source package: http://download.sf.net/qtractor/qtractor-0.8.0-28.rncbc.suse.src.rpm - - binary packages: http://download.sf.net/qtractor/qtractor-0.8.0-28.rncbc.suse.i586.rpm http://download.sf.net/qtractor/qtractor-0.8.0-28.rncbc.suse.x86_84.rp m Git repos: http://git.code.sf.net/p/qtractor/code https://github.com/rncbc/qtractor.git https://gitlab.com/rncbc/qtractor.git https://bitbucket.org/rncbc/qtractor.git Wiki (on-going help wanted!): http://sourceforge.net/p/qtractor/wiki/ License: Qtractor [1] is free, open-source Linux Audio [5] software, distributed under the terms of the GNU General Public License (GPL [6]) version 2 or later. Change-log: - - MIDI clip tools redo/undo processing refactored as much to avoid replication over multiple hash-linked clips; MIDI clip editor's floating selection/anchor event stability has been also improved, in regard to MIDI tools processing range. - - Auto-backward play-head location, when playback was last started, is now shown on main track-view, as a momentary dark-red vertical line marker. - - LV2 plugin-in parameter optimization: stuff consecutive series of plug-in's parameter value changes, as much as possible into one single undo/redo command. - - LV2_STATE__StateChanged is now recognized as a regular atom notification event and raising the current session dirty flag, as normal behavior. - - Adjusting clip selection edges is now possible and honored while on the the main track-view canvas. - - Audio peak file caching and rendering, as far as audio clip wave-forms are concerned, have been refactored and optimized a couple of notches higher, on the ephemeral and rather marginal throughput front ;). - - Fixed a potential crash on the singleton/unique application instance setup. - - Edit/Select Mode tool-buttons moved into single drop-down tool-button on the main and MIDI editor's tool-bar. - - Do not reset the current clip selection when updating the main track-view extents eg. while zooming in or out. - - Automation curve node editing auto-smoothing revisited; also fixed input MIDI RPN/NRPN running status processing, which was crippling some plug-in automation curve nodes, when saved in high-resolution 14-bit mode. - - Fixed the visual play-head position (vertical red line) while zooming in or out horizontally. - - Almost complete overhaul on the configure script command line options, wrt. installation directories specification, eg. --prefix, - --bindir, --libdir, --datadir and --mandir. - - LV2 Plugin-in worker/schedule fix: make request/response ring-buffer writes in one go, hopefully atomic (suggested patch by Stefan Westerfeld, while on SpectMorph, thanks). References: [1] Qtractor - An audio/MIDI multi-track sequencer http://qtractor.sourceforge.net [2] Qt framework, C++ class library and tools for cross-platform application and UI development http://qt.io/ [3] JACK Audio Connection Kit http://jackaudio.org [4] ALSA, Advanced Linux Sound Architecture http://www.alsa-project.org/ [5] Linux Audio consortium of libre software for audio-related work http://linuxaudio.org [6] GPL - GNU General Public License http://www.gnu.org/copyleft/gpl.html [7] The QStuff* Fall'16 Release http://www.rncbc.org/drupal/node/1773 [8] Vee One Suite 0.8.0 - A Fall'16 Release http://www.rncbc.org/drupal/node/1775 See also: http://www.rncbc.org/drupal/node/1777 Enjoy && Keep the fun. - -- rncbc aka Rui Nuno Capela -----BEGIN PGP SIGNATURE----- iQEcBAEBCAAGBQJYMxxzAAoJEEnqU1AwGtTIkk4H/0bb4dCrfYHox/WqUfkPFHCT GyuXGjp3zOcXzxrA6NL9eI1QshSPL3ZVB+Pt7WGfeaHMOKlb7dWO69ASGSUUEBZ3 uq/4gs+/3kA7LgDrZ8TCaLmLdSpfGPu+CUNWzH6xxIdoQ1uawunQrAGJvWgNtdR+ hkrt1e45hrBZm3CeIXw1I2tCeN2FScK87uJubFc1g4l131CEFBHGnWEiDPg+5BZ0 MK82D6qUBcfsHcWFXoYbIlfx/QyHLuBgg9vJrl0xQDuCGOjqd6zjyH605q/NBHMM +xmzLuzIyn0BV7j43hKDytKVTeWSTQttUtav3Pv5cN3yzhT8xIQFUcFcCXJ8uMg= =sHa0 -----END PGP SIGNATURE-----

9 years, 1 month

MIDI over Bluetooth Low Energy on Linux

by Felipe Ferreri Tonello

Hi everyone, Just want to let people know that the initial release of the MIDI over BLE drivers for Linux are ready and waiting for review on the linux-bluetooth mailing list[1]. Hopefully it will be release on the next version of BlueZ. I invite everyone to test it out and review the patch so we can improve it as much as possible. There is also a video[2] I made just to demonstrate it working on a Linux desktop, but I have also tested on Embedded Systems such as Raspberry Pi 2 successfully. If you want more information on how to setup your system to work properly, please let me know. PS: I would like send kudos to ROLI Ltd.[3] since they allowed me to work on this as a full-time job. [1] https://marc.info/?l=linux-bluetooth&m=147948132904058&w=4 [2] https://www.youtube.com/watch?v=eKnC9_Buxus [3] https://roli.com/ -- Felipe

9 years, 1 month

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Linux-audio-dev