Linux-audio-dev

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7516 discussions

[linux-audio-dev] A "best" event delegation strategy?

by Lukas Degener

Hi list, Here is a propblem that is propably already solved in another context, so i would like to know some opinions on it: I am trying to implement a (hopefully:-) ) simple general-purpose event delegation architecture. The actual application will propably be something like a network of modules that can do arbitrary filtering, generation and manipulation of midi events in real time. As propably different kinds of external event sources, like several midi ports, maybe joystick device and of course a gui, are involved, how would one efficiently organize the delegation of events passed between the modules, so that the everything is still thread-safe? The three main ideas i can currently think of are: A: don't do it at all, that is, everything is implemented as simple subject/observer patterns, so that the communication is a pure module-to-module thing. Mutexes et al, would have to be managed by each individual plugin. B: use a global, mutexed event queue. This could be a priority queue for time-stamped events, or a simple FIFO. C: use local queues. As above, but for each individual module. Each of the above aproaches seems to have its advantages and disatvantages. E.g. if queues are used, this would as far as i an judge, make it easy to have feedback cycles. OTOH this would propably introduce some overhead which aproach A wouldn't have. C would propably involve a single thread for each module, or a global "clock" thread that periodicaly calls an "process_queue" method on each module. Is there a general "best" way to do this? Kind regards, Lukas

22 years, 5 months

[linux-audio-dev] [ANN] tuneroid 0.9.3

by Jozef Kosoru

tuneroid 0.9.3 tuneroid is a tuner for variety of musical instruments. It is designed to tune musical instruments on PC using a microphone or directly connecting the instrument to the PC's sound card. http://www.uid0.sk/zyzstar/?tuneroid -- jozef kosoru http://www.uid0.sk/zyzstar

22 years, 5 months

[linux-audio-dev] [ANN] swh-plugins 0.4.2

by Steve Harris

http://plugin.org.uk/releases/0.4.2/ Highly recomended upgrade for 0.4.x users. Changes: * Great new set of filter plugins from Alexander Ehlert * Applied patch from Anand Kumria to make it build with gcc 3.3 * Rewrote the flanger modulation code - its not optimised, but should work * Added support for FFTW3 * Added denormal killer to l/c/r delay - hopefully works better on PIV * Fixed serious peak detection bug in lookahead limiter * Things I forgot Thanks to Nick T. and Anand K. for bug reports and Alexander E. for the new plugins. FFTW3 is much better than old versions, but if youre going to upgrade make sure you tell it to build the 32bit library, and optimise it right for your CPU. The SIMD optimisations (SSE etc.) make a lot of difference. FFTW2 will be supported for the near future anyway. - Steve

22 years, 5 months

[linux-audio-dev] FIFOs vs. sockets

by Hans Fugal

On linux, which is faster, pipe, FIFO, or socket? What about shared memory - is it faster, and if so is it faster enough to warrant the extra programming overhead? -- Hans Fugal | De gustibus non disputandum est. http://hans.fugal.net/ | Debian, vim, mutt, ruby, text, gpg http://gdmxml.fugal.net/ | WindowMaker, gaim, UTF-8, RISC, JS Bach --------------------------------------------------------------------- GnuPG Fingerprint: 6940 87C5 6610 567F 1E95 CB5E FC98 E8CD E0AA D460

22 years, 5 months

[linux-audio-dev] [OT] Analog circuit design?

by Paul Winkler

Sort of off-topic, except that i want to do it on linux and it does have to do with audio :) I've been wanting to tinker a bit with analog audio circuit design. I've built a few boxes from schematics but I've never actually designed a circuit. What I'd REALLY like is some GUI software in which I can construct a circuit diagram and then feed in a test audio signal and through some DSP magic, hear (more or less) what the result would sound like before I start using my big clunky hands to ruin physical objects :) Does such a thing exist? Or some combination of software that would do the above? I've been looking at some SPICE resources online but I can't tell if you can feed an arbitrary digitized audio signal into a SPICE simulation. -- Paul Winkler http://www.slinkp.com Look! Up in the sky! It's PURPLE KABUKI WARRIOR BOOMERANG! (random hero from isometric.spaceninja.com)

22 years, 5 months

[linux-audio-dev] [OT] Linux Music & Sound Software site updated

by Dave Phillips

Greetings: As of May 30 2003 the Linux Music & Sound Applications sites have been updated. The site may be reached here: http://linux-sound.org (USA) Here: http://www.linuxsound.at (Europe) And here: http://linuxsound.jp (Japan) Best regards, == Dave Phillips The Book Of Linux Music & Sound at http://www.nostarch.com/lms.htm The Linux Soundapps Site at http://linux-sound.org

22 years, 5 months

[linux-audio-dev] high-res time measurement?

by jacob robbins

I'm a little green at time measurement facilities available in linux, In my host, I would like to be able to measure how much time each individual LADPSA plugin takes. Assuming I do realtime work with the smallest buffer sizes my system can handle, what options are available to me to measure time on this small scale? I know that the typical system calls time and gettimeofday have resolution of 10 ms, which is too big for this purpose. Is there any way to do this? Is there a high-res time howto? -jacob robbins.....

22 years, 5 months

[linux-audio-dev] NPTL and real-time sched semantics

by Kai Vehmanen

Has anyone done any low-latency audio testing with the new native pthread implementation (comes with rh9.0 at least)...? I was just reading through [1] and noticed the following (in section 8): ""Realtime support is mostly missing from the library implementation. The system calls to select scheduling parameters are available but they have no effects. The reason for this is that large parts of the kernel do not follow the rules for realtime scheduling. Waking one of the threads waiting for a futex is not done by looking at the priorities of the waiters."" If I've understood right, SCHED_FIFO semantics do not have any meaning between threads of one process if NPTL is used! Hopefully this is right, as it would cause quite a lot of problems (GUIs and disk i/o threads can freely block audio processing even though using SCHED_FIFO). :( [1] http://people.redhat.com/drepper/nptl-design.pdf -- http://www.eca.cx Audio software for Linux!

22 years, 5 months

[linux-audio-dev] LADSPA RDF additional information?

by Richard Guenther

Hi Steve, hi others! I'm just adding lrdf support to glame but apart from default values I dont see more information than in the ladspa descriptor. Can we agree on some more metatags? I'd like to have - a Category (or multiple ones?) - short description of ports and the plugin itself - URI to the documentation of the plugin am I right getting such information would be done via the lrdf call lrdf_get_setting_metadata? So we need to define element labels for the above. I'd suggest - category - description - help_uri Thoughts? Richard.

22 years, 5 months

[admin] Re: [linux-audio-dev] AMERÝKA'DA YAÞAMAK ÝSTER MÝSÝNÝZ ?

by Joern Nettingsmeier

ABD/GÖÇMENLÝK wrote: [some turkish spam bs] shit. they sneaked it past the html filter. but i'm reluctant to plonk all multipart messages, many mailers produce them by default. guess we have to live with it for now. -- All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations. -- Charter of the United Nations, Article 2.4 Jörn Nettingsmeier Kurfürstenstr 49, 45138 Essen, Germany http://spunk.dnsalias.org (my server) http://www.linuxdj.com/audio/lad/ (Linux Audio Developers)

22 years, 5 months

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Linux-audio-dev