Linux-audio-dev March 2013

linux-audio-dev@lists.linuxaudio.org

40 participants
31 discussions

by Victor Lazzarini

The deadline for submission of papers for DAFX13 has been extended to SUNDAY APRIL 14th More information on http://dafx13.nuim.ie/authors.html You can also follow us on twitter https://twitter.com/DAFxInfo We're looking forward to your submission! Dr Victor Lazzarini Senior Lecturer Dept. of Music NUI Maynooth Ireland tel.: +353 1 708 3545 Victor dot Lazzarini AT nuim dot ie

12 years

DAFX13 - deadline extension.

by Victor Lazzarini

The deadline for submission of papers for DAFX13 has been extended to April 14th. More information on http://dafx13.nuim.ie/authors.html You can also follow us on twitter https://twitter.com/DAFxInfo We're looking forward to your submission! Dr Victor Lazzarini Senior Lecturer Dept. of Music NUI Maynooth Ireland tel.: +353 1 708 3545 Victor dot Lazzarini AT nuim dot ie

12 years

Handling of expression controller in fluidsynth and linuxsampler

by Nikita Zlobin

Trying to get live strings and vocal in linuxsampler, i was suprised by fact, that this controller doesn't have effect (with all engines and banks, including suggested for fluidsynth), but with fluidsynth all ok. It is not clear now, how this controller should be handler at all. I expected, that it should be same as for velocity, but set for enter channel and variable, unlike V, specified for notes and constant). I searched both in fluidsynth and qsynth sources to see, for handling code, but found in fluidsynth only two constants (EXPRESSION_LSB and EXPRESSION_MSB) and command, setting these parameters to default value (127). IMHO, it is very necessary for linuxsampler, and who knows, what is not done for fluidsynth. Looks like LS devs left it for user (using qmidiroute, mididings or sequencer's builtint converting capabilities if available). This link only confirms that: http://bb.linuxsampler.org/viewtopic.php?f=6&t=207

12 years

Mixing audio: Noiseless volume changes

by Tim E. Real

Hi again. Looking for any advice, tips, tricks, anecdotes etc. I want to eliminate or reduce 'zipper' noise on volume changes. So I'm looking at two techniques: Zero-crossing / zero-value signal detection, and slew-rate limiting. Code is almost done, almost ready to start testing each technique. Each technique has some advantages and disadvantages. If I use a slew-rate limiter, I figure for a sudden volume factor change from 0.0 to 1.0, if I limit the slew rate to say 0.01 per sample then after 100 samples the ramp will be done. But even with a fine ramp, this still might introduce artifacts in the audio. If I use a zero-crossing/zero-value detector and apply volume changes only at these safe points, that's a much more desirable 'perfect' system. But I stuck a time limit on waiting for a zero-cross because it's possible the signal might have a high DC offset, or contain VLF < 20Hz. (One cannot simply wait for the current data value to be 'zero' because for example with a perfect square wave signal the 'current' value will never approach zero, hence the zero-crossing detection requirement.) At some point waiting for a zero-cross, a ramp would have already finished and it may have been better to use that ramp instead. Conversely, a zero-cross might happen sooner than a ramp could finish, and we definitely want to use that zero-cross here instead of the ramp. So it means I either have to give the user a choice of the two techniques, or try to automatically switch between them - which ever one occurs first, the ramp finishing or the zero-cross, use it. But it means I have to keep two audio buffers - one for applying the ramp as the samples are processed, and one for waiting until zero-cross happens - and which ever one "finishes the race" first, that buffer "gets the nod". The zero-crossing technique has some interesting implications. For a stereo signal each channel's zero-cross will happen at different times. So I'm trying to imagine what that's going to sound like where the volume changes happen at slightly different times, if it will be noticeable, even though that is far better than 'zipper' noise. Also I'm trying to imagine how track cross-fading support would deal with zero-crossing - if it is better to use ramps in that case. What do you think? Thanks. Tim.

12 years

SysV init scripts vs. systemd, a short note

by Fernando Lopez-Lezcano

Hi all, Hopefully this will be useful to others. I just wrote a short note describing my experiences when moving from a SysV init script based OpenMixer[*] system to one that uses systemd. In short, yes, it is possible, no, it was not easy (mostly because of my own ignorance of systemd, of course :-) https://ccrma.stanford.edu/~nando/plog/20130315/ Enjoy! -- Fernando [*] OpenMixer is a mixing and routing application written in SuperCollider that manages audio for our 22 channel 3D Listening Room. It has to start on boot and runs as the "openmixer" user and group, and I wanted it to not use a regular Desktop "autologin" feature but rather be a SysV init service... https://ccrma.stanford.edu/room-guides/listening-room/ https://ccrma.stanford.edu/software/openmixer/manual/

12 years

[ANN] Qtractor 0.5.8 - The India Romeo is out, singing a serenade...

by Rui Nuno Capela

Spring is nigh. Qtractor 0.5.8 (india romeo) is out, singing a serenade... Nothing but the change-log (see below:)) Enjoy && lots of fun. Website: http://qtractor.sourceforge.net Project page: http://sourceforge.net/projects/qtractor Downloads: - source tarball: http://downloads.sourceforge.net/qtractor/qtractor-0.5.8.tar.gz - source package (openSUSE 12.3): http://downloads.sourceforge.net/qtractor/qtractor-0.5.8-5.rncbc.suse123.sr… - binary packages (openSUSE 12.3): http://downloads.sourceforge.net/qtractor/qtractor-0.5.8-5.rncbc.suse123.i5… http://downloads.sourceforge.net/qtractor/qtractor-0.5.8-5.rncbc.suse123.x8… - quick start guide & user manual: http://downloads.sourceforge.net/qtractor/qtractor-0.5.x-user-manual.pdf Weblog (upstream support): http://www.rncbc.org License: Qtractor is free, open-source software, distributed under the terms of the GNU General Public License (GPL) version 2 or later. Change-log: - Dropped old audio ramping spin-locks as its glitching reduction weren't that effective anymore. - Audio bus and track gain may now be set for amplification again, from +0dB up to +6dB, while using the Mixer strip sliders/faders (an old function found missing ever since pre-TYOQA). - Basic LV2 X11 UI support has been added through libSUIL but only really effective if plugins doesn't support the LV2 External UI extension in addition which takes precedence on any case. - Improved precision tolerance on the Tempo Map / Markers dialog. - Reinstated and fixed (old) warning and impending re-conversion on loading session files which the original sample-rate differs from current audio device engine (aka. JACK). - LV2 Plugin State/Preset name discrimination fix (after a ticket by Jiri Prochaszka aka. Anchakor, thanks:) - Linked/ref-counted audio clips must not overlap and now must have a buffer-size worth of a gap between each other. - Something fishy has been detected in the SSE (not so) optimized code from SoundTouch's-inspired WSOLA time-stretching. - Splitting clips apart is now easier than ever: a brand new entry enters the main menu scene: Edit/Split (Ctrl+Y) splits up clips according to current range/rectangular selection. - Audio clip offsets are now properly corrected when time-stretching is applied via Shift/Ctrl+dragging any of the clip edges. - One semi-colon typo was hiding proper descrimination of peak files used to draw distinct waveforms of time-stretched audio clips. - Track automation curves are now also affected by Edit/Insert/Range commands. - Finally, some visual feedback is shown while audio track export is running, in he form of a main status progress bar. - New user option: save backup versions of existing session files. - Default session directory now set to regular file's path on load. - A convenient minimum slack duration has been fixed for MIDI SysEx messages. - LV2 Time/position information is now asynchronously fed back into their parameter (control input) ports when designated. - LV2 State is now properly restored for plugins inserted on buses, probably solving the Calf Fluidsynth SoundFont information missing on buses ticket, reported by Albert Graef, thanks. - Fixed an immediate null pointer crash on creating a parentless new group while on the files organizer widget. - Preparations for future Qt5 migration. Cheers! -- rncbc aka Rui Nuno Capela rncbc(a)rncbc.org

12 years

phat gtk

by Ulrich-Lorenz Schlueter

Hi list, does anyone have plans to put phat gtk+ back online, is there still a maintainer? Regards Uli

12 years

Laborejo Release 0.6 - Beta phase has started

by Nils Gey

Laborejo, Esperanto for "Workshop", is used to craft music through notation. It is a Lilypond GUI front-end, a MIDI creator and finally a tool collection to inspire and help you compose. Laborejo 0.6 is released. It now has an internal soundfont (and sfz) engine, comes with a lightweight General Midi sample set and supports jack midi outputs. New Midi-In implementation. Parameters and values for both engines are separated. You can use the same file for big orchestrated playback with gigabytes over gigabytes of sampled instruments and external synthesizers and maintain a parallel General Midi version which can be played back even if the samples are not there or running (laptop, work in a train, "just compose for 10 minutes", send it to friends for a preview etc.) This marks the end of the Alpha phase and beginning of the Beta phase. That means the current features are enough to make and handle a reasonable range of music and notation and also that the save format is now stable. If you manage to save a file you will be able to load it in later versions. Versions from now up to 1.0 will be only bug fixes and improvements: Stability, Performance, Documentation, Convenience as well as Look&Feel. (There are a few new features I would like to see in 1.0, but these are convenience features that do not disturb the save format or internal data format. Read-Only) Documentation and Translation can now be based on a somewhat stable program. Yes, there will be documentation. Cross Platform versions, stand-alone/portable packages and collaboration with distribution package maintainers is now on the Roadmap. Further information and instructions Connect to Laborejos Facebook, Twitter or Google Plus! https://www.facebook.com/Laborejo https://twitter.com/#!/Laborejo https://plus.google.com/b/116744898976321238325/ Screenshot: http://www.laborejo.org/images/screenshots/latestscreenshot.png Download: https://github.com/nilsgey/Laborejo/tarball/0.6 Dependencies and Compilation instrunctions: http://www.laborejo.org/Download Start the GUI Editor with: ./laborejo-qt For commandline parameters: ./laborejo-qt --help and the Collection Editor with: ./laborejo-collection-editor Then use the number- and cursor keys for immediate success! Check Help->Manual for navigational and note/rest entry keys. Everything else is in the menus. Greetings, Nils http://www.laborejo.org

12 years

RFP: Channel Linux - BETA

by Patrick Shirkey

Hi, Some of you might be interested in my new project. It's been a few years in the making http://channellinux.com We have big plans for this new project. Please let me know if you come across anything that you think would be interesting for the viewing audience and please link to the site everywhere you have an opportunity. If you help me to grow the traffic and keep the content coming it will pay back to the community tenfold. Please refrain from replying to this post with content links or feedback on the site. I'm sure everyone knows my position by now so I will refrain from commenting on replies to this post too :-) TECHNICAL I have created two separate threads for this on each list so if people want to navel gaze and politic, please refrain from doing that on LAD ;-) The site is designed to work on all screen sizes but has only been tested on Firefox and Chrome. I am not interested in testing on other browsers. The ones that don't work are either broken or do not have a large enough user base to justify my time. I am interested in results on small screen mobile devices. Not because I don't know what will happen but because I would like to hear some more ideas for how to tweak the layout to work more effectively. If you have any ideas for that please reply to this thread ON LAD ONLY or send me a direct email. Ideas for UX improvements on usability or additional media types like livecast, radio and audio streaming will also be very helpful. As above please send me a separate email or eply to this thread ON LAD ONLY. I know some of you on this list have many years of experience in the industry so your ideas will be taken seriously and implemented with gusto. Due to the "BETA" mode this is not a finished product. I am posting here as a preliminary announcement to get some usability testing and feedback results from a wider pool of knowledgable technical users. At a later date I will push for an official release announcement. ADVERTISING The long term plan for this project is to generate income from advertising just like a regular TV/Radio station and feed that back to the community by paying people to create content. During the Beta period I am offering free advertising to interested companies to allow me to test and iron out the usability for a new format of internet advertising across multiple devices. This is still fresh ground so no one has really nailed it yet. I have several companies already participating but I am still working out the display mechanism for the various ads that have been provided to me across all devices and screen sizes. If you have thoughts on ways to achieve this please reply to this thread ON LAD ONLY BACKGROUND Linux Audio and Multimedia has a large and thriving community of developers, creators, artists and users. FLOSS and GNU/Linux has an even larger global community of people who are passionate about their OS of choice and wear the badge of FLOSS and GNU/Linux proudly whenever they have the chance. One thing has been missing. A dedicated Channel for all things Linux Multimedia. Sure, there are lots of news sites out there and many communities and people that produce digital content but no one has really taken on the task of collating all the various media spread out across the internet into a one stop and easy access portal. But why stop there? GNU/Linux is the dominant operating system on the planet and enables or creates billions of dollars in revenue for some of the largest companies on the planet. As a global community we effectively power the internet, create the worlds best movies, participate in and drive scientific progress at the highest level, power the next generation of green technology, send rockets into space, enable governments to operate efficiently and even feed and power the world. Why not take things to the next level and create a truly cross device experience for mobile, desktop and TV? We have the knowledge to make it happen. However there is also a problem facing the global pool of artists and developers who dedicate their time to FLOSS multimedia. We don't get the kind of financial support that we deserve for all our efforts. The big companies barely spend a fraction of their wealth on supporting and growing the FLOSS multimedia tools that enable us to entertain the world. What can we do about that? We don't have to sit here crying into our milk. We can generate our own income and feed that back into the community by promoting and marketing to the global community of people interested in FLOSS and GNU/Linux. It doesn't mean we have sold out. It just means we are using what we have got to make things better. Channel Linux is in Beta mode and it might stay like that for some time. The first step is growing the traffic to the site. The next step is taking that traffic and making it work for us. Companies are prepared to pay serious cash if they have a guaranteed way to reach their target market. So what does it all mean? We need content, lots of it. We need constructive feedback and suggestions for making the site really hit the sweet spot of usability and entertainment. And we need your links, tweets, facebook likes and passionate evangelism to help us grow the traffic to the kind of numbers that companies with serious cash are prepared to spend their money on. We have the capacity if we choose to use it. I hope you are prepared for the ride :-) -- Patrick Shirkey Boost Digital / Boost Hardware Ltd

12 years

[ANN] MFP 0.02 (Music For Programmers, a graphical patching system)

by Bill Gribble

MFP -- Music For Programmers Release 0.02, "Making Fine Progress" I'm pleased to announce an updated release of MFP, containing many fixes and improvements. It is still not anywhere near a "production" level, but is becoming more and more usable. Your interest and participation are invited! A summary of changes is below. Please see the GitHub issue tracker for complete details: https://github.com/bgribble/mfp Changes since initial release v0.01: ---------------------------------------- * #30: Fix RMS calculation in [ampl~] * #37: Add [s~], [r~] and different via graphics for signals * #41: Clean up SSE vs non-SSE, add tests for non-SSE build * #42: Make parameter setting non-locking; add mfp_alloc thread for non-blocking memory allocation; in general, clean up RT components of operation * #43: Refactor color name usage to avoid API breakage with different versions of Clutter python bindings * #44: Fix broken tests * #46: Add ability to load .so extension libraries with new DSP types * #47: Handle JACK block size changes at runtime * #48: Add [latency] object to report JACK input and output latency changes to patches 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 constructing audio synthesis, processing, and analysis networks. 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 * 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 * 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. The code is still in early days, but has reached a point in its lifecycle where at least some interesting workflows are operational and it can be used for a good number of things. I think MFP is now ripe for those with an experimental streak and/or development skills to grab it, use it, and contribute to its design and development. The code and issue tracker are hosted on GitHub: https://github.com/bgribble/mfp You can find an introductory paper (submitted to LAC-2013) and accompanying screenshots, some sample patches, and a few other bits of documentation in the doc directory of the GitHub repo. The README at the top level of the source tree contains dependency, build, and getting-started information. Thanks, Bill Gribble

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Linux-audio-dev March 2013