Linux-audio-dev March 2006

linux-audio-dev@lists.linuxaudio.org

87 participants
76 discussions

[linux-audio-dev] Writing PCM to left and right channel sperately?

by Tobias Scharnberg

Hello List, I'm new to audio programming and have problems finding the right solutions for the development I work on right now: I need to use the left and the right audio channel seperately. The device is an ARM based board with a AC97 soundchip. It seems to work with OSS so far and I did choose libsdnfile to open Soundfiles and get the PCM. As far as I learned the audio data is coded in one stream, one sample left, one sample right. Is there a way to separately fill the soundcard buffers with ALSA? The only solution I can think of right now is to recode the audio data to left only or right only and to use a library like esound to mix them together. Is this the right way to do such a thing? Any suggestions, pointers, hints are highly welcome. Greetings, Tobias

19 years

[linux-audio-dev] options in capturing audio off a PlusDeck?

by Sean Dague

I got myself one of the PlusDeck units last summer after having received some documentation from the product team about their serial control protocol, so I figured that I'd have some chance at actually making a recording program for Linux for it. The impetus for all of this is a stack of 300 or so audio tapes that my fiancee has, which contain mostly south Indian music recordings, including training lessons, from her late teacher T Viswanathan. Some of those probably don't exist anywhere else at this point, so putting them to digital would be a good thing (tm). Anyway, I have 2 goals. First, the practical, get all this music to digital dumps (flac in ogg containers for metadata seems to be the best bet). I'm trying to figure out the best ways to do this on a Mandriva Linux 2.6.12 kernel (on an AMD64 3000+ processor running 32bit, with Via onboard sound.) The PlusDeck just ends up being an input line jack into the sound card. I've run some tests with ecasound both straight off the alsa device, and through ecasound to jackd (both as root to get real time). It is hard to tell if I'm doing better with jackd or not, but I'm making some long recordings and letting my musical fiancee tell me if she can hear the difference. :) Given that I've got the serial protocol sorted out, it seems like the practical approach is just a command line ripper that will start up all the right audio bits, start the tape, and stop when the tape gets to the end. Full automation is what I'm looking to create. Is ecasound a good option here? How much better will ecasound + jackd be over ecasound at realtime? Would building some kind of plusdeck control plugin for another recording program make more sense? If so, which one? Second, I'd like to turn whatever I learn during the practical phase into a reasonable open source Linux tool for using the PlusDeck. I'd be a bit unnerved if that required that I set up all jack & ecasound bits, as well as kicked them off as setuid root, but better options are failing me at the moment. Any advice, ideas, suggestions, questions... even flames would be welcomed. I've spent a bit of time learning more than I ever thought I'd end up knowing about Linux audio already, and know I have a whole lot more I need to learn still. Thanks in advance, -Sean -- __________________________________________________________________ Sean Dague Mid-Hudson Valley sean at dague dot net Linux Users Group http://dague.net http://mhvlug.org There is no silver bullet. Plus, werewolves make better neighbors than zombies, and they tend to keep the vampire population down. __________________________________________________________________

19 years

Re: [linux-audio-dev] Writing PCM to left and right channel seperately?

by Ben Loftis

Tobias, I wrote a program that does just this some years ago for IED (www.iedaudio.com). What you are doing is not trivial. When an announcement starts on the left channel (for example) you will want to fill the right channel with zeroes. However you must fill the buffers in small blocks so that if an announcement starts on the right channel, you can start stuffing the right channel without a long delay. You might want to investigate Paul's program JACK for this. It splits the audio into separate buffers for each I/O. If you really have to have it ASAP, why not just buy an IED system? :) -Ben

19 years

[linux-audio-dev] Reliability of SPDIF sync w/ onboard audio?

by drclaw＠dogsolitude.org

Ok, given a pair of commodity Linux PC's with cheapo onboard audio codecs capable of SPDIF input and output, assuming I sent identical input signals into both machines and didn't perform any processing in the middle, could I reasonably expect the output signals to be synchronized, or should I expect unpleasant phasing / delay effects when listening to both channels simultaneously as a result of the inherently flakey consumer-grade codecs? The above is a simplification that should address my major concern... The goal here is to use a pair of redundant, inexpensive machines for live midi-controlled (headless) playback where the physical security of the location is lax enough that using my laptop + hammerfall would be too risky, not to mention 35 channels worth of overkill. Ideally these two machines would accept some sort of SPDIF format square-wave from some low power clock logic on their inputs and play identical, pre-cached wav files on their outputs when they recieve simultaneous "go" signals from the MIDI playback desk. Any experiences or opinions are welcome... Thanks, - Mike Piantedosi

19 years

[linux-audio-dev] jack.udp and synchronisation

by Asbjørn Sæbø

jack.udp may be used to transmit audio between two computers, each computer running their own jackd. My understanding, based upon earlier threads in the linux audio lists, is that to avoid xruns due to clock drift in this situation, the sound cards of the two computers must be synchronised in some way, e.g. using word clock. Is this (still) correct? Or has jack.udp been developed to include synchronisation? (On a side note, it seems that Rohan Drape's web pages that are linked to from the jack pages, http://www.alphalink.com.au/~rd/sw/jack.html, have disappeared.) Asbjørn Sæbø

19 years

[linux-audio-dev] Gerard van Dongen/Gilcher 1967-2006

by derek holzer

Gerard van Dongen/Gilcher passed away on Friday the 4th of March, after a brave battle with colon cancer. Gerard worked as a composer, musician and computer programmer in Rotterdam as well as played live with many improvisational and electronic musicians in the Netherlands including Bart Maris, Tom Wouters, Joe Williamson, Henk Bakker, Peter van Bergen and Ann LaBerge. He performed solo-concerts with electronics and/or piano compositions and played for numerous dance and theatre productions, produced radio-plays for the internet, and was a technical designer and software programmer for multimedia theater. Gerard was also an active member of the Pure Data and Linux Audio Developers communities, and contributed code for the user interface of the Ardour project. Gerard kept a very positive outlook throughout his illness, and he will certainly be missed. Marie Louise Gilcher has organized a memorial service for Thursday, 9 March at the "Crooswijk" Cemetery in Rotterdam. -- derek holzer ::: http://www.umatic.nl ---Oblique Strategy # 118: "Make what's perfect more human"

19 years

[linux-audio-dev] a bit off topic: GUI-lib-programming (how does it usually work?)

by Julien Claassen

Hi! I know, this may be a bit off topic. But I've a dificulty: I'm currently programming a textbase "GUI"-lib. I want the programming API to be similar to on of a real GUI-lib (gtk, you name them). Now I'm wondering, there are menus. Menus have menuitems and if you click on one, something should happen. How is this "something should happen" part usually done? - I thought of the java-apporach, deriving your own menu-class. But it doesn't feel right. I have my dificulties with trying GUI-libs myself, for I'm blind. I could write some code, but wouldn't know, if it works, like I planned. Any thoughts, help on this, anyone? I would be greatful! Kindest regards Julien -------- Music was my first love and it will be my last (John Miles) ======== FIND MY WEB-PROJECT AT: ======== http://ltsb.sourceforge.net - the Linux TextBased Studio guide

19 years

[linux-audio-dev] Creating an api for an exsisting project

by jjbenham＠chicagoguitar.com

I am working on project that does not have an api. I was wondering where to find information on building an api. We have a plugin system but the user needs the entire source if they want to build a plugin. The project I am talking about is Denemo (A gtk frontend to lilypond). Jeremiah

19 years

[linux-audio-dev] [ANN] Rhythm Galaxy vol. 1 drum/percussion sample library

by Artemiy Pavlov

Dear Linux audio software users and developers, many of you may know me - a sound designer behind many free sounds I keep on making for Hydrogen rhythm machine and other samplers. Now I am pleased to announce Rhythm Galaxy vol. 1 - an all-new sound library which boasts a huge load of drums, percussion and effects - from analog and digital emulations to brand new, amazing sounds. It is a low-cost but very high-quality library which delivers just the right sounds for various styles. Rhythm Galaxy vol. 1 includes over 250 world-class, superb sounds which satisfy the needs of professional composers and music-making lovers who have been searching for fresh, unique and inspiring material. All sounds are totally original material, they have been created completely from scratch, using Roland Fantom-S, V-Synth and VC-1 synthesizers, Krok 2401 analog vocoder and also ALSA Modular synth. Rhythm Galaxy is available in two formats: - .WAV files grouped in folders ("Kick", "Snare", etc.) - suitable for any hardware/software sampler - Hydrogen drum kit with all 256 sounds (will work only in Hydrogen 0.9.4 sound library manager). Sound demo: http://soniccharger.com/media/demos/Rhythm_Galaxy_1_demo.mp3 Specs and complete sample list: http://soniccharger.com/media/manuals/Rhythm_Galaxy_manual.pdf More info: http://store.rolandclan.info/?action=catalogueViewItem&category=4&id=RGALAX… You can also read more about me and my works at http://sineshine.com. Sincerely, Artemiy.

19 years

Re: [linux-audio-dev] a bit off topic: GUI-lib-programming (how does it usually work?)

by Steve

Also check out http://www.gobolinux.org/abstk/ which supports ncurses and Qt back-ends. Unfortunately no GTK though, and I don't know about what development state it is in. steve > On 3/6/06, Cedric Roux <Cedric.Roux(a)eurecom.fr> wrote: > > On Mon, 6 Mar 2006, Florian Schmidt wrote: > > > > > I always wondered whether it was possible to do something like a > > > generic/abstract UI thing. You bind yourself to ncurses at the moment, > > > but wouldn't it be cool, if the same code could sit ontop of either > > > ncurses or X/Gtk/Qt, or even be communicated via audio interface and user > > > talking. > > > > [...] > > > > > Anyone know if such a thing exists yet? Or any thoughts on the matter? > > > > > > Flo > > > > What about uiml? > > http://www.uiml.org/ > > > > xul could also be an answer, but maybe not. Take a look at it. > > http://www.mozilla.org/projects/xul/ > > > > Take care, > > Cédric. > > > > > >

19 years

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Linux-audio-dev March 2006