Linux-audio-dev August 2011

linux-audio-dev@lists.linuxaudio.org

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26 discussions

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Faust MIDI?

by Carlo Capocasa

Hi, is it possible to send and receive MIDI with a FAUST program? Carlo

10 years, 10 months

RDF libraries, was Re: [ANN] IR: LV2 Convolution Reverb

by Chris Cannam

On 23 February 2011 22:11, David Robillard <d(a)drobilla.net> wrote: > SLV2 is now based on two new libraries: Serd (RDF syntax) and Sord (RDF > store). Both are roughly 2 thousand lines of C, solid and thoroughly > tested (about 95% code coverage, like SLV2 itself). Serd has zero > dependencies, Sord depends only on Glib (for the time being, possibly > not in the future). Can you point me at the API or code? I couldn't see it in a quick browse on your SVN server. I have a library (Dataquay, http://code.breakfastquay.com/projects/dataquay -- preparing a 1.0 release of it at the moment, so if anyone wants to try it, go for the repository rather than the old releases) which provides a Qt4 wrapper for librdf and an object-RDF mapper. It's intended for applications whose developers like the idea of RDF as an abstract data model and Turtle as a syntax, but are not particularly interested in being scalable datastores or engaging in the linked data world. For my purposes, Dataquay using librdf is fine -- I can configure it so that bloat is not an issue (and hey! I'm using Qt already) and some optional extras are welcome. But I can see the appeal of a more limited, lightweight, or at least less configuration-dependent back-end. I've considered doing LV2 as a simple example case for Dataquay, but the thought of engaging in more flamewars about LV2 and GUIs is really what has put me off so far. In other words, I like the cut of your jib here. Chris

11 years, 5 months

someone can smash this seq24 bug?

by Renato

Hello, seq24 is affected by this bug: https://bugs.edge.launchpad.net/seq24/+bug/803385 basically with recent versions of jack, when jack transport is enabled, seq24 doesn't start playing. This makes it practically unusable, which is a real pity :( any brave dev want to give him some love? eternal glory will ensue :) cheers renato

11 years, 6 months

Inter thread Communication: Design Approach

by Harry van Haaren

Hey All, I'm looking to improve a program's design with regards to how it communicates between the "jack" thread and its "main/gui" thread. Please note I'm *not* looking for implementation details like what ringbuffer to use, this has been discussed here before. Conditions: Gui needs to feed data trough to the jack thread (data = parameter moves etc) Jack thread needs to push data (buffers for waveforms & "playhead" info) The real question: What is a neat solution to passing various data trough a ringbuffer? My (hacky?) solution: Create a class, call it "Event". Runtime now looks like so: 1. Create a EventType enum, set the details 2. Write those "Events" into the ringbuffer 3. Switch based on EventType, and handle the event. While not terribly ugly, that Event class starts to get bigger & nastier, so I concidered sub-classing it... but I'm not sure this is going in the right direction. I'm very intrested how the "big" programs around have approached this problem... Cheers, -Harry

11 years, 6 months

a *simple* ring buffer, comments pls?

by James Morris

just wondered if any more-experienced-than-i devs might comment on this. written in c for c (obviously). i realize it's not portable outside of GNU GCC (regarding the GCC atomic builtin funcs __sync_***). meant for a single reader thread and a single writer thread. comments regarding thread safety very much welcome. thanks in advance. james. #include "rng_buf.h" /* only prototypes the public functions and typedefs the struct */ #include <stdlib.h> #include <string.h> #include "debug.h" struct _RingBuffer { size_t count; void** buf; void** bufend; void** volatile w; void** volatile r; }; RngBuf* rng_buf_new(size_t count) { size_t sz = 1; RngBuf* mb = malloc(sizeof(RngBuf)); if (!mb) { return 0; } for (sz = 1; sz < count; sz <<= 1) ; mb->buf = calloc(sz, sizeof(void*)); if (!mb->buf) { free(mb); return 0; } mb->count = sz; mb->bufend = mb->buf + mb->count - 1; mb->w = mb->buf; mb->r = mb->buf; return mb; } void rng_buf_free(RngBuf* mb) { free(mb->buf); free(mb); } size_t rng_buf_write(RngBuf* mb, const void* data) { if (__sync_bool_compare_and_swap(mb->w, 0, data)) { if (!(__sync_bool_compare_and_swap(&mb->w, mb->bufend, mb->buf))) __sync_add_and_fetch(&mb->w, sizeof(void*)); return (size_t)1; } return (size_t)0; } void* rng_buf_read(RngBuf* mb) { void* data; if ((data = __sync_fetch_and_and(mb->r, 0))) { if (!__sync_bool_compare_and_swap(&mb->r, mb->bufend, mb->buf)) __sync_add_and_fetch(&mb->r, sizeof(void*)); return data; } return NULL; } void rng_buf_reset(RngBuf* mb) { /* needs work */ mb->r = mb->w = mb->buf; }

11 years, 6 months

Jack_session

by thijs van severen

Hi all My name is Thijs and i have been helping out with Hydrogen for some time now (mainly manual, website and a tiny bit of coding) Anyway, since jack_session support was recently added to Hydrogen (in V0.9.6 that is currently still in development but available from svn via hydrogen-music.org) i decided to test jack_session a bit and i must say i'm really exited about this :-) IMHO this is the most critical piece of the puzzle and it makes linux audio _so_ much more usable! so lots of KUDOS to everyone that has been working on it !! I have done several 'intro sessions' for Mac audio users and they are generally really impressed with what they see, but the lack of a good session management mechanism is a real showstopper for them... (i know there are other options, but none of those have ever allowed me to truly save my session *at any given moment*) however, the first thing that slowed me down was simply knowing what apps already support jack_session i know that jack_session is fairly new, so it's normal that some info is missing, but it would be great if the websites out there that list the available linux audio apps (like http://apps.linuxaudio.org/apps/categories/jack) would also indicate if the app supports jack_session the jack_session page on the jackaudio.org wiki<http://trac.jackaudio.org/wiki/WalkThrough/User/jack_session>also lists a number of apps, but i don't think it's up to date, is it ? any comments? grtz Thijs PS: i'd be happy to help out with documenting jack_session if needed PS: it would be nice to have a 'jack_session enabled app' banner to put on the site of the apps that support it. graphical designers ? -- follow me on my Audio & Linux blog <http://audio-and-linux.blogspot.com/> !

11 years, 7 months

interesting article on why most "music apps" fail

by Paul Davis

the discussion is about consumer-oriented apps, but its an interesting one anyway ... http://www.billboard.biz/bbbiz/industry/digital-and-mobile/why-most-music-a…

11 years, 7 months

[LAA][ANNOUNCE] New LV2 Soft Synth: The Newtonator v0.5.0

by Michael Bechard

Brand new LV2 plugin soft synth here. The Newtonator (v0.5.0) features: * LV2-compliant synth plugin * Simple, easy-to-use GTK-based GUI * 3-note polyphony (err, um, until I can do some serious optimization) * "Unique" synthesis algorithm (Tuna Pagan Fellowship) The Newtonator specializes in making crazy, harsh sounds, so if you're looking for some sounds to produce the next Yanni album, keep looking. Please refer to the user manual (http://newtonator.sourceforge.net/manual/index.html) for more gory details. Download: http://sourceforge.net/projects/newtonator/files/newtonator-0.5.0.tar.gz/do… NOTE: This plugin was written against the excellent libraries included in the lv2-c++-tools package written by Lars Luthman. However, as of v1.0.4, the GUI library only supports rev. 2 of the LV2 specification, so it may have problems on newer hosts (though I have done some (very) preliminary testing against Ardour3 and it seems to work ok). Alpha testing mostly done against zynjacku and Elven (comes with ll-plugins package) hosts. This puppy's in beta, so feel free to get in touch with me at the project forum (https://sourceforge.net/projects/newtonator/forums/forum/1820765) or submit a bug if needed. Thanks, and have fun. Michael Bechard https://sourceforge.net/projects/newtonator/

11 years, 7 months

RT-Safe UI/Engine Decoupling using Functional Programming and Reference Counted SmartPointers

by Florian Paul Schmidt

Hi, during the process of writing a new small jack sampler which fits my workflow I came up with this little scheme to solve the UI/engine decoupling problem. For the purpose of spreading the idea or alternatively getting answers about how it's broken and sucks I decided to write a little article describing it.. http://178.63.2.231/~tapas/wordpress/?page_id=45 The (largely unfinished and unusable) sampler project is here: https://github.com/fps/jass Let me have it.. Regards, Flo

11 years, 7 months

[HELP WANTED] ALSA Driver developer

by Gabriel Beddingfield

All: A recruiter approached me looking for an ALSA driver developer to enhance an existing driver. This is a short-term, off-site gig. Some details below. Please contact Mr. DeAmelio directly. Thanks, Gabriel ---------- Forwarded message ---------- From: David DeAmelio <david_deamelio(a)oxfordcorp.com> Date: Tue, Aug 16, 2011 at 2:29 PM Subject: Job Description - Oxford International To: gabrbedd(a)gmail.com Hey Gabriel, Here’s the description….Thanks. Location: OFFSITE Start Date: ASAP Duration: 1-2 Weeks Manager needs consultant to come onsite for 1st few days. Client will pay for flight there and back. Must: Linux ALSA Device Drivers—Alsa- advanced linux sound architecture Blackfin Plus: D2D: Consultant will be enhancing an audio driver to support a voice quality recorder __________________________________ David De Amelio Team Lead Software/Hardware Consulting Services Oxford International a division of Oxford Global Resources 100 Cummings Center Suite 206N Beverly, MA 01915 877.258.9982 x 7608 Office 978.922.7547 FAX david_deamelio(a)oxfordcorp.com www.oxfordcorp.com Oxford Europe The Right Talent. Right Now.® This e-mail, and any attachments thereto, is intended only for the addressee(s) named herein and may contain privileged and/or confidential information. If you are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, immediately notify the sender by return e-mail and permanently delete the original, including any attachments thereto, and any copy and printout thereof.

11 years, 7 months

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Linux-audio-dev August 2011