Linux-audio-dev May 2003

linux-audio-dev@lists.linuxaudio.org

71 participants
56 discussions

[linux-audio-dev] Call for participation: MMA GMPI working group

by RonKuper＠Cakewalk.com

The Generalized Music Plug-In Interface (GMPI) working group of the MIDI Manufacturer's Association (MMA) is seeking the input of music and audio software developers, to help define the technical requirements of GMPI. The objective of the GMPI working group is to create a unified cross-platform music plug-in interface. This new interface is hoped to provide an alternative choice to the multitude of plug-in interfaces that exist today. Among the many benefits of standardization are increased choice for customers, lower cost for music plug-in vendors and a secure future for valuable market-enabling technology. Like MIDI, GMPI will be license free and royalty free. Phase 1 of the GMPI working group's effort is to determine what is required of GMPI: What sorts of capabilities are needed to support existing products and customers? What are the emerging new directions that must be addressed? Phase 1 is open to any music software developer and is not limited to MMA members. It will last a minimum of three months, to be extended if deemed necessary by the MMA. Discussions will be held on an email reflector, with possible meetings at major industry gatherings such as AES, NAMM and Musik Messe. Following the collection of requirements in Phase 1, the members of the MMA will meet to discuss and evaluate proposals, in accordance with existing MMA procedures for developing standards. There will be one or more periods for public comment prior to adoption by MMA members. If you are a developer with a serious interest in the design of this specification, and are not currently a member of the MMA, we urge you to consider joining. Fees are not prohibitively high even for a small commercial developer. Your fees will pay for administration, legal fees and marketing. Please visit http://www.midi.org for more information about membership. To participate, please email gmpi-request(a)freelists.org with the word "subscribe" in the subject line. Please also provide your name, company name (if any) and a brief description of your personal or corporate domain of interest. We look forward to hearing from you. Sincerely, Ron Kuper GMPI Working Group Chair

21 years, 2 months

[linux-audio-dev] sc synth definition file format?

by Dr.Graef＠t-online.de

Hi, I'm currently embarking on a project to make an interface between Q, a functional programming language (http://www.musikwissenschaft.uni-mainz.de/~ag/q/), and SuperCollider. I think the OSC interface will be fairly straightforward to do, but I haven't been able to find any documentation (besides the sc sources, which I haven't grokked yet ;-) on the format of the synth definition file. Does anyone here know more about this? Many thanks in advance, Albert -- Dr. Albert Gr"af Email: Dr.Graef(a)t-online.de, ag(a)muwiinfa.geschichte.uni-mainz.de WWW: http://www.musikwissenschaft.uni-mainz.de/~ag

21 years, 4 months

[linux-audio-dev] Bristol Synth

by Anthony

Hi, I've been playing a lot with bristol synth and really love it. So much so that I've been trying to 'Jackify' it. Actually, I'm pretty much done, but can't figure out the internal audio format. Its interleaved floats I think, but not normalised to [-1,1]. If any of the developers are here could you help me out? I can hear noise, but I need to tune the maths. TIA. --ant

21 years, 6 months

[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

21 years, 6 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

21 years, 6 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)

21 years, 6 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

21 years, 6 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.....

21 years, 6 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!

21 years, 6 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.

21 years, 6 months

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Linux-audio-dev May 2003