Linux-audio-dev February 2009

linux-audio-dev@lists.linuxaudio.org

44 participants
26 discussions

Linux Audio Awards : postponed to 2010

by Patrick Shirkey

Hi, In the spirit of organizing a well executed Awards ceremony and due to lack of interest from the business community in sponsoring the inaugural Linux Audio Awards for 2009 I have decided to withdraw from organising the event and will postpone the inaugural event to the next Linux Audio Conference in 2010. Hopefully conditions will be more suitable for sponsors to get involved next year. Cheers. // -- Patrick Shirkey Boost Hardware Ltd.

15 years, 7 months

Library for accurate time stamping using a DLL

by Olivier Guilyardi

Hi everyone, Fons, thanks to your essay "Using a DLL to filter time" [1], that you mentionned in a discussion we had in August, I've put together a small library, named Pendule, for accurate timing within a real time context. It's a tiny piece of code, but offers a very easy to use replacement for gettimeofday(). Plus, it includes some benchmarking/measuring tools, that produce that sort of fancy graphics (this one using a PCI hda intel card): http://www.samalyse.com/code/pendule/shortgraph.png Usage is very simple. first create an instance: #include <pendule.h> Pendule *pendule = pendule_new(buffer_size / sample_rate, bandwidth); Then, in the realtime thread, update the loop every process cycle: pendule_cycle(pendule); And use pendule_gettime() instead of gettimeofday(): double current_time_in_seconds = pendule_gettime(pendule); As expected, looking at the graph above, the obtained time doesn't drift as the audio time, and has a lower jitter than the system time. Well, at least, it works for me. However, although my measures are pretty encouraging, I am not 100% sure of my DLL implementation. Could you please review it ? It's there: http://svn.samalyse.com/pendule/trunk/src/pendule.c You can grab everything using svn: svn co http://svn.samalyse.com/pendule/trunk pendule I'd like to know how it works for others. You can easily test your hardware/system and make graphs with: ./waf configure ./waf build ./measure ./graph Check the README for more. [1] http://www.kokkinizita.net/papers/usingdll.pdf Best regards, -- Olivier

15 years, 7 months

Re: [LAD] [LAU] LAC2009 website update

by Fons Adriaensen

On Mon, Feb 02, 2009 at 12:49:32PM -0800, Ken Restivo wrote: > Wow, it's in Italia! I'd love to go. Alas, I can't; > the airfare alone from SFO to Milano would be around > US$1000... there's no way I can come up with that kind > of money. You're not the first US resident to deplore this... What happened to all those cheap transatlantic flights ? Petrol prices are down... > Also I've never been to Italy myself (sono io > cento-per-cento italiano, ma nato a New York), > and I'm a bit afraid to go, since if I do, > I might not ever want to come back. *sigh* I'm not so sure of that... The US finally have a respectable president, we still have Berlusconi. Italy is in crisis - and not only the economy. Last weekend some kids (youngest was 17, and all from 'respectable' families) set fire to a homeless Indian sleeping outdours, just 'per divertirsi'... Ciao, -- FA Laboratorio di Acustica ed Elettroacustica Parma, Italia O tu, che porte, correndo si ? E guerra e morte !

15 years, 7 months

LAC2009 website update

by Fons Adriaensen

Hello all, Some quick LAC2009 news. The LAC2009 website now has some info on travelling to and staying in Parma. <http://lac.linuxaudio.org/2009/> In the bed & breakfast category there is one more which will be added soon: DUCALE, Via Costituente 11, 43100 Parma <http://digilander.libero.it/bbducale/> If you look at the map on this website (click on the foto), the CdM is very near to the place marked 'Duomo'. 10-15 min from the conference site, depending on your walking speed. La Casa della Musica on Google maps: <http://maps.google.it/maps?f=q&hl=it&geocode=&q=piazzale+san+francesco+parma> Robin Gareus and Christoph Haag are working on getting the registration page on line. Ciao, -- FA Laboratorio di Acustica ed Elettroacustica Parma, Italia O tu, che porte, correndo si ? E guerra e morte !

15 years, 7 months

AMB-plugins update

by Fons Adriaensen

Hello all, On popular demand (which means Joern Nettingsmeier has been prodding me) there's an update of the Ambisonic LADSPA plugins. Version 0.4.0 adds a 2nd order periphonic panner and horizontal rotator (i.e. 9-ch output). Have a look at the README - channel orders of the existing 2,1 plugins and the new 2,2 ones are not the same. As always <http://www.kokkinizita.net/linuxaudio/downloads> The fa-plugins.rdf has been updated as well. Ciao, -- FA Laboratorio di Acustica ed Elettroacustica Parma, Italia O tu, che porte, correndo si ? E guerra e morte !

15 years, 7 months

Re: [LAD] sound dissipation in air - formulas and filters? (Maitland)

by Maitland Vaughan-Turner

J?rn Nettingsmeier <nettings(a)folkwang-hochschule.de> sez: > > true, for this particular case it would do (and that's what i'm using > atm). but i have this idea for a plugin that takes actual mic distance, > temperature, humidity and desired distance as parameters and will do > something that is reasonably correct (not taking into account sound > diffraction or reflection at temperature boundary layers, obviously). > would be kind of cool, but i need to get a deeper understanding of the > physics involved... especially the dependance on humidity is a very > tricky and quite non-linear issue. > > fons is probably right that it doesn't make all that much of a > difference, but since such a plugin could be a nice learning tool for > sound engineers, i'd want it to be as precise as reasonably possible. This sounds like a really interesting project to me, and I wish you all the best in completing it! Aside from being a nice learning tool, I'm sure it will be a *very* nice creative tool, as well. I can't wait to hear what it sounds like to modulate humidity with a sine wave! ~Maitland

15 years, 7 months

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Linux-audio-dev February 2009