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L2Ork story on Slashdot brings up the age-old question whether Linux is ready for serious audio use

by Ivica Ico Bukvic

Dear fellow FOSS enthusiasts, This is probably already old news according to Internet standards but as it turns out we spent a good time this evening in class not knowing that we got slashdotted. For those interested in belatedly joining the discussion, please visit: http://entertainment.slashdot.org/story/09/12/03/2018253/Introducing-L2Ork-W orlds-First-Linux-Laptop-Orchestra Best wishes, Ivica Ico Bukvic, D.M.A. Composition, Music Technology Director, DISIS Interactive Sound & Intermedia Studio Assistant Co-Director, CCTAD CHCI, CS, and Art (by courtesy) Virginia Tech Dept. of Music - 0240 Blacksburg, VA 24061 (540) 231-6139 (540) 231-5034 (fax) ico(a)vt.edu http://www.music.vt.edu/faculty/bukvic/

15 years, 11 months

[LAA] [ANN] guitarix-0.05.3-1 quick release

by hermann

This is a quick guitarix update to cover the new release of jconvolver eg. jconv guitarix is a simple Linux Rock Guitar amplifier and is designed to achieve nice thrash/metal/rock/blues guitar sounds. Guitarix uses the Jack Audio Connection Kit as its audio backend and brings in one input and two output ports to the jack graph. To cover the renaming of jconv to jconvolver, guitarix-0.05.3-1 looks now first for jconvolver, if it isn't installed, it looks for jconv. Also a patch from Michal Seben (OpenSuse) is added to cover a build fail at openSUSE:Factory. Thanks Michal. :-) Additional, there is a (rt) 2 Channel delay chooser for the output to jconv, and the Chorus effect work in Stereo now. have fun ________________________________________________________________________ Project page with screenshots: http://guitarix.sourceforge.net/ download: http://sourceforge.net/projects/guitarix/ ________________________________________________________________________ For capture, guitarix uses the external application 'jack_capture' (version >= 0.9.30) written by Kjetil S. Matheussen. If you don't have it installed, you can look here: http://old.notam02.no/arkiv/src/?M=D For extra Impulse Responses, guitarix uses the convolution application 'jconv' created by Fons Adriaensen. If you don't have it installed, you can look here: http://www.kokkinizita.net/linuxaudio/index.html I(hermann) use faust to build the prototype and will say thanks to : Julius Smith http://ccrma.stanford.edu/realsimple/faust/ : Albert Graef http://q-lang.sourceforge.net/examples.html#Faust : Yann Orlary http://faust.grame.fr/ guitarix is licensed under the GPL. regards Hermann Meyer & James Warden ------------------------------------------

15 years, 11 months

Re: [LAD] [LAU] [LAA] [ANN] guitarix-0.05.2-1 released

by hermann

Am Donnerstag, den 03.12.2009, 14:04 +0100 schrieb Hartmut Noack: > hermann schrieb: > > I'm happy to announce a new guitarix release > > > > guitarix is a simple Linux Rock Guitar amplifier and is designed > > to achieve nice thrash/metal/rock/blues guitar sounds. > > Guitarix uses the Jack Audio Connection Kit as its audio backend > > and brings in one input and two output ports to the jack graph. > > Nice one, thatnk you :-) > > I love to see this project grow - a simple works-right out of the box > amp for Linux is extremely welcome. > BTW: do you think, you could turn it into a LV2-plugin? > > Some people could consider then to boost stability and performance of > their Linux audio system by dropping VST via WINE.... > Thanks Hartmut, good to hear that you like it. :-) Make guitarix a LV2-plugin, is at least a question of development power. We would love that to, but, Guitarix is a young small project, we are only 2 developers, and we both have at first other tasks in mind witch we wone implement. In fact, it will be easy for a bit experienced LV2 developer to port the "control chain" of guitarix to LV2. Our source is spiked with comments witch make it easy to jump in and grep the needed source. Guitarix is a open Project, open for developers who wone join the project. gruß hermann

15 years, 11 months

jack ringbuffer question

by lieven moors

Hi everyone, I just started writing my first c++ program, and I'm kind of stuck with something I cannot understand. After a few days of trying to figure this out, I decided to ask for more professional help. I'm working on a kind of arpeggiator for linux (which I intend to release under GPL). The program uses a text file, in which the user can specify a number of arpeggios. Each arpeggio is loaded into an object called 'Arp', and for every Arp I make a jack port, and a ringbuffer. (the port and ringbuffer are stored in an object called Arp_jack) A seperate thread, watches the text file for modifications (using inotify), and every time the file is changed, the file is loaded afresh, and the new Arps are put in the respective ringbuffers. The ringbuffers have a size of two Arps, and the idea is that when a new Arp arrives, the old one is discarded. If there is only one Arp in the buffer, the program keeps on reading the same one. This code is part of the inotify thread: while (i < len) { struct inotify_event *event; event = (struct inotify_event *) &buf[i]; if ( event->wd == wd ) { vector<Arp>* arps = new vector<Arp> ; read_load_file( arps ) ; for( uint x = 0; x < arps->size(); x++ ) { const char* arp_char = reinterpret_cast<const char*>(&(*arps)[x]); jack_ringbuffer_write( (*ARPS_JACK)[x].rb, arp_char, sizeof( Arp )); } //delete arps ; } The next code fragment comes from the process callback. As you can see, I'm using jack_ringbuffer_get_read_vector to read the raw data, and I advance the the read pointer when a new arp is available: if( (jack_ringbuffer_read_space( (*arps_jack)[i].rb ) ) == (sizeof( Arp ) * 2) ) { jack_ringbuffer_read_advance( (*arps_jack)[i].rb, sizeof(Arp) ) ; } if( (jack_ringbuffer_read_space( (*arps_jack)[i].rb ) ) == sizeof( Arp ) ) { jack_ringbuffer_data_t data[2] ; jack_ringbuffer_get_read_vector( (*arps_jack)[i].rb, data ) ; if ( data[0].len > 0 ) { arp = reinterpret_cast<Arp*>( data[0].buf ) ; steps = &arp->steps ; scale = &arp->scale ; } else if( data[1].len > 0) { cout << "data in second part of ringbuffer, this should not happen!" << endl ; } .... Now to the question. The code works as I expect, as long as I don't delete the vector of arps in the inotify thread (see the commented line). When I do delete the vector, the program segfaults. (and also when I allocate the vector on the stack, and it gets cleaned up automatically) I thought that writing to the ringbuffer with jack_ringbuffer_write copies the data to the ringbuffer, so I don't understand why this should have an influence. Is it a problem that I put the ringbuffer in an object which is accessed by two different threads without using a mutex? I've tried using a mutex,but I still had the segmentation fault. Any help with this would be really appreciated. Thanks for your help, Lieven

15 years, 11 months

HDMI Audio

by Jens M Andreasen

Seing that HDMI interfaces are getting implemented everywhere - a bit like S/PDIF before that, but now with 8 uncompressed channels @192k and 24 bits - does anybody know what kind frame sizes are used and what the implications would be for realtime audio-processing? (.. as opposed to buffering up and re-playing pre-recorded material from a DVD.) Not that I am aware of anything reasonable to connect to at the receiving end yet - but who knows, that might change.

15 years, 11 months

Re: [LAD] [LAU] Update of jconv

by fons＠kokkinizita.net

On Wed, Dec 02, 2009 at 12:39:27PM -0800, Ken Restivo wrote: > Does the "partition" parameter in the conf file affect this? Yes, it determines the minumum partition size that will be used. The only difference between the two examples I posted is the value of this parameter, 256 or 4096. > On the reverbs I've been using successfully with freewheeling > mode, the "partition" is set to 2048, which is very high compared > to the setting in the sample reverbs tthat come with jconv. Which means you will have significant delay. If the reverb is use as an effect (rather than to recreate real room acoustics) this could actually be beneficial. On a single processor machine freewheeling should just work, and not depend on this paramter. Ciao, -- FA Wie der Mond heute Nacht aussieht ! Ist es nicht ein seltsames Bild ?

15 years, 11 months

Re: [LAD] jack ringbuffer question

by Kjetil S. Matheussen

lieven moors: >> >>> I want to repeat the same Arp, until there is an update to the text file. >>> One arp is allready >>> loaded in each ringbuffer in main(). When the file is modified, a second one >>> is added, and >>> process skips to the second one. Since I have only space for two arps in the >>> buffer, there >>> should always be exactly one which is readable. I know it is a bit weird, >>> but it seems to >>> work, apart from the problem I described. >>> >> >> sounds as if you might want to look into atomic pointer and/or integer >> exchange instead, to get lock-free double buffering. >> >> ringbuffers are generally for passing streaming data/events. >> >> > Could you give me a hint on how to use atomic pointers? I've used the lockless lifo/fifo-queue implementations found in midishare a few times. Those are really simple to use: http://midishare.sourceforge.net/

15 years, 11 months

[OT]: help L2Ork climb up the digg/reddit ladder

by Ivica Ico Bukvic

First of all, Apologies for cross-posting. If it is not too much of a trouble, I was wondering if I could ask fellow FOSS enthusiasts to help us in "digging" & "reddit-ing" our L2Ork announcement posted on reddit and dig earlier today. Links to the posts can be found below: <http://www.reddit.com/r/reddit.com/comments/aa12z/who_says_penguins_cannot_ sing_introducing_l2ork/> <http://digg.com/linux_unix/Introducing_L2Ork_World_s_First_Linux_Laptop_Orc hestra> Once again, apologies for the OT nature of this post. Sincerely, Ivica Ico Bukvic, D.M.A. Composition, Music Technology Director, DISIS Interactive Sound & Intermedia Studio Assistant Co-Director, CCTAD CHCI, CS, and Art (by courtesy) Virginia Tech Dept. of Music - 0240 Blacksburg, VA 24061 (540) 231-6139 (540) 231-5034 (fax) ico(a)vt.edu http://www.music.vt.edu/faculty/bukvic/

15 years, 11 months

[LAA] [ANN] guitarix-0.05.2-1 released

by hermann

I'm happy to announce a new guitarix release guitarix is a simple Linux Rock Guitar amplifier and is designed to achieve nice thrash/metal/rock/blues guitar sounds. Guitarix uses the Jack Audio Connection Kit as its audio backend and brings in one input and two output ports to the jack graph. Release 0.05.2-1 comes with some changes: * remove dependency of the boost library (Many thanks to "thrasher13b" for the patch) * fix missing "./" in ./debian/rules reported by GMag (AV Linux) * add 2 Channel gain and delay chooser to the Jconv settings widget. * add scroll/zoom mode to the wave view * reworked Jconv settings widget UI * various GUI and feature clean-up's have fun Comments and suggestions are welcome. ________________________________________________________________________ The standalone version of guitarix is based on GTK2+. But guitarix is also released as a suite of LADSPA plugins and can be used in e.g. ardour. guitarix is licensed under the GPL. Project page with screenshots: http://guitarix.sourceforge.net/ download: http://sourceforge.net/projects/guitarix/ For capture, guitarix uses the external application 'jack_capture' (version >= 0.9.30) written by Kjetil S. Matheussen. If you don't have it installed, you can look here: http://old.notam02.no/arkiv/src/?M=D For extra Impulse Responses, guitarix uses the convolution application 'jconv' created by Fons Adriaensen. If you don't have it installed, you can look here: http://www.kokkinizita.net/linuxaudio/index.html I(hermann) use faust to build the prototype and will say thanks to : Julius Smith http://ccrma.stanford.edu/realsimple/faust/ : Albert Graef http://q-lang.sourceforge.net/examples.html#Faust : Yann Orlary http://faust.grame.fr/ regards Hermann Meyer & James Warden ------------------------------------------ guitarix-dev team

15 years, 11 months

some questions about writing a jack client

by mutil

hello everyone, I am trying to write a c++/qt4 jack client which mix 2 inputs and has a jack output. The problem is that currently jack gets zombified too often and I would like some info on how can I debug the exact reason this happens. I suspect it's the way the app is written and I am planning to rewrite it but I need some advices first. The way it's currently written makes use of mutexes and locks to pass the data beetween a custom global buffer. Is this the reason for not synchronizing good enough and zombifies jack or it's something else that screw things? Should I use a ringbuffer (which, to my understanding is lock-free and doesn't need mutexes) to get the work done, and if so, are there any jack2 example of this or some hints for what I should be aware of? Or have I misunderstand something completely? Please, any recommendation of how I can eliminate this "jack zombified" thing and understand the whole realtime issue is welcome. Thank you in advance.

15 years, 11 months

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Linux-audio-dev