Linux-audio-dev January 2017

linux-audio-dev@lists.linuxaudio.org

7 participants
8 discussions

by Tim Goetze

http://quitte.de/dsp/caps.html The latest release of the caps audio plugin suite contains a number of bug fixes and improvements as well as changes intended to make it more suitable for low-power systems. http://quitte.de/dsp/caps.html#CHANGES Most notably, support for a variety of little-used features has been dropped, reducing the binary size by roughly a third. There's also a new plugin implementing simplistic linear emulation of several guitar amplifier loudspeaker cabinets with reduced computational complexity: http://quitte.de/dsp/caps.html#CabinetIII The compressor plugins now report current gain reduction: http://quitte.de/dsp/caps.html#Compress http://quitte.de/dsp/caps_0.9.24.tar.bz2 Cheers, Tim

5 years, 1 month

RME Digiface USB ?

by Damien Zammit

Hey, Anyone got one of these? Does it work with GNU/Linux (yet)? Curious about xrun performance with 4x ADAT i/o over USB2... Regards, Damien

6 years, 10 months

[LAA] [LAU] First release of GxPlugins.lv2

by Hermann Meyer

Hi I like to announce the first release of GxPlugins.lv2 GxPlugins.lv2 is a set of mostly analogue guitar pedal simulations as LV2 plugins, simulated with the guitarix ampsim toolkit. They contain the following plugs: GxBottleRocket.lv2 - -> tube based preamp pedal GxHotBox.lv2 - -> tube based preamp pedal GxVBassPreAmp.lv2 - -> transistor based Bass preamp GxSuppaToneBender.lv2 - -> transistor based preamp GxHyperion.lv2 - -> transistor based Fuzz pedal GxVoodoFuzz.lv2 - -> transistor based Fuzz pedal GxSaturator.lv2 - -> saturation plugin GxVintageFuzzMaster.lv2 - -> transistor based Fuzz pedal GxSuperFuzz.lv2 - -> transistor based Fuzz pedal GxVmk2.lv2 - -> transistor based solid stage preamp GxUVox720k.lv2 - -> transistor based solid stage preamp GxSlowGear.lv2 - -> volume swell plugin GxGuvnor.lv2 - -> transistor based overdrive pedal GxToneMachine.lv2 - -> transistor based Fuzz pedal I hope they may be useful for the one or the other. Build instruction and screenshots may be found here: https://github.com/brummer10/GxPlugins.lv2 the release zip file is located here: https://github.com/brummer10/GxPlugins.lv2/releases regards hermann

6 years, 10 months

[ANN] MFP 0.06 is released

by Bill Gribble

MFP -- Music For Programmers Release 0.06 I'm pleased to announce a new version of MFP, mostly consisting of bug fixes and improvements. It's been about 2 years since the 0.05 release, but lately I have been pretty energized! A summary of changes is below. Please see GitHub for complete details: http://github.com/bgribble/mfp This version is still source-code-only, but the new build system should make it a bit easier for those who would like to try it. Significant changes since release v0.05 ---------------------------------------- * Build issues reported for the 0.05 release have been fixed or mitigated * Clarification of semantics around names and namespaces (scopes) * A change to send/receive semantics may break patches saved with earlier versions of mfp, if they make use of vias and scopes * New demo patches and fixes to old ones * Improvements to performance, stability and error handling * Left-side tabs and bottom-edge console/log can be toggled with ` and ~ respectively * Better default color selections, and the ability to set per-object style (colors, fonts) in your patches * Many other bugfixes and improvements. The complete list of tickets closed since the 0.05 release is in the 0.06 milestone: http://github.com/bgribble/mfp/issues?q=milestone%3A%22mfp+0.06%22+is%3Aclo… About MFP ---------------------------------------- MFP is an environment for visually composing computer programs, with an emphasis on music and real-time audio synthesis and analysis. It's very much inspired by Miller Puckette's Pure Data (pd) and Max/MSP, with a bit of LabView and TouchOSC for good measure. It is targeted at musicians, recording engineers, and software developers who like the "patching" dataflow metaphor for coding up audio synthesis, processing, and analysis. MFP is a completely new code base, written in Python and C, with a Clutter UI. It has been under development by a solo developer (me!), as a spare-time project for several years. Compared to Pure Data, its nearest relative, MFP is superficially pretty similar but differs in a few key ways: * MFP uses Python data natively. Any literal data entered in the UI is parsed by the Python evaluator, and any Python value is a legitimate "message" on the dataflow network. This makes it much easier to make patches that work like conventional "programs". * MFP provides fairly raw access to Python constructs if desired. For example, the built-in Python console allows live coding of Python functions as patch elements at runtime. * Name resolution and namespacing are addressed more robustly, with explicit support for lexical scoping. This allows patches to have dynamic or parameterized content, with hygienic layer copying preserving lexical structure without name collisions * The UI is largely keyboard-driven, with a modal input system that feels a bit like vim. The graphical presentation is a single-window style with layers rather than multiple windows. * There is fairly deep integration of Open Sound Control (OSC), with every patch element having an OSC address and the ability to learn any other desired address. MIDI controller learning is also robustly supported. * MFP has just a fraction of the builtin and addon functionality provided by PD. It's not up to being a replacement except in very limited cases! The code and issue tracker are hosted on GitHub: https://github.com/bgribble/mfp You can find the LAC-2013 paper and accompanying screenshots, some sample patches, and a few other bits of documentation in the doc directory of the GitHub repo. The README files at the top level of the source tree contain dependency, build, and getting-started information. More sample patches are in my personal patch repo: https://github.com/bgribble/mfp-patches Where's it going? ---------------------------------------- I've been working on MFP as a spare time project for almost 7 years now. The likelihood that it will ever have more than a few users is low. Luckily, that doesn't bother me much; MFP is a tool I am building mainly for my own use and education. That being said, if there's something about it that appeals to you, I welcome your interest and participation. Thanks, Bill Gribble <grib(a)billgribble.com>

6 years, 10 months

Grouping of software on the wiki?

by Chris McKenzie

6 years, 10 months

Re: [LAD] QTractor: QThreads: Not realtime on Linux without root?

by Felipe Ferreri Tonello

Hi Ralf, On 11/01/17 12:52, Ralf Mattes wrote: > > Am Mittwoch, 11. Januar 2017 13:21 CET, Felipe Ferreri Tonello <eu(a)felipetonello.com> schrieb: > >> Hi Ralf, >> >> On 03/01/17 21:37, Ralf Mattes wrote: >>> >>> Am Dienstag, 03. Januar 2017 19:31 CET, Felipe Ferreri Tonello <eu(a)felipetonello.com> schrieb: >>> >>> >>>> If sched_setscheduler() returns -1, check if errno is set to EPERM. In >>>> this case the user trying to perform this operation does not have >>>> CAP_SYS_NICE[1] capability, which is *required*. >>>> >>>> [1] http://man7.org/linux/man-pages/man7/capabilities.7.html >>>> >>>> If you want this type of feature, set CAP_SYS_NICE to the group audio >>>> that you are referring. >>> >>> ??? How can I grant capabilities to a group? I thought capabilites where either given to >>> a user (via /etc/security/capability.conf) or to a binary (by means of setcap). >> >> AFAIK, pam_cap support users and groups. > > Not according to my local manpages (pam_cap(8) 09/23/2011 and CAPABILITY.CONF(5) -- 09/23/2011). > Do you have any y reference for your information? I never tested, but try out based on this reference[1] paragraph 2.2. Apparently there are two implementations for pam_cap. One supports the other doesn't. [1] http://blog.sevagas.com/?Linux-security-using-a-limited-group-PAM-modules [2] https://github.com/ekline/pamcap/blob/master/pam_capability.c [3] https://github.com/pexip/os-libcap2/blob/master/pam_cap/pam_cap.c Good luck. -- Felipe

6 years, 10 months

Fwd:?==?utf-8?q? Re:?==?utf-8?q? QTractor:?==?utf-8?q? QThreads: Not realtime on Linux without root?

by Ralf Mattes

Am Mittwoch, 11. Januar 2017 13:21 CET, Felipe Ferreri Tonello <eu(a)felipetonello.com> schrieb: > Hi Ralf, > > On 03/01/17 21:37, Ralf Mattes wrote: > > > > Am Dienstag, 03. Januar 2017 19:31 CET, Felipe Ferreri Tonello <eu(a)felipetonello.com> schrieb: > > > > > >> If sched_setscheduler() returns -1, check if errno is set to EPERM. In > >> this case the user trying to perform this operation does not have> >> CAP_SYS_NICE[1] capability, which is *required*. > >> > >> [1] http://man7.org/linux/man-pages/man7/capabilities.7.html > >> > >> If you want this type of feature, set CAP_SYS_NICE to the group audio > >> that you are referring. > > > > ??? How can I grant capabilities to a group? I thought capabilites where either given to > > a user (via /etc/security/capability.conf) or to a binary (by means of setcap). > > AFAIK, pam_cap support users and groups. Not according to my local manpages (pam_cap(8) 09/23/2011 and CAPABILITY.CONF(5) -- 09/23/2011). Do you have any y reference for your information? TIA Ralf Mattes

6 years, 10 months

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.

6 years, 10 months

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Linux-audio-dev January 2017