Linux-audio-dev

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7520 discussions

implementing audio device driver on embedded platforms

by Jugalkishore Darak, Pankaj

Hello Developers, I am a newbie to the Linux development environment. We are porting Linux 2.6.25.4 to a platform which has ARM11 as its core processor. My job is to implement audio device driver. Most of the docs are meant for PC audio which has sound cards on PCI. And the source code resides in sound folder under the kernel root. Since mine is an embedded platform, where will my architecture specific code resides? Which all folders under sound folder will be used for embedded devices and which APIs to look into? Which APIs will be called for system sounds ? Can anybody share their experience in implementing audio device driver on embedded platforms? Thanks a lot in advance. Regards, Pankaj

16 years, 5 months

[ANN] Invada Studio Plugins - version 1.1.0

by Fraser

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Everyone, I've released a new version of the Invada LV2 plugins. Major changes are: * Added new plugin: 'Delay - Munge'. A delay with non-linear response in the feedback loop. The 'munge' affect is more noticeable the higher the feedback. Also features a LFO and delay calculator. Screenshot: http://www.invadarecords.com/images/downloads/Screenshot-Invada_Delay_Munge… * Added new plugin: 'Test Tones' This was more for myself but others may appreciate this. Just a simple sine oscillator but via the custom GUI the frequency can be set to well known calibration and musical frequencies. Useful if you need to fault find, calibrate analogue equipment or if desperate to tune an instrument when you have no tuner handy. * Eliminated 'zipping' from changing controls. All plugins now handle parameter changes (across the entire range) without producing any audio artefacts ('zipping' noises). No issues with automation of controls. * Filters now adjustable from the display Adjust filters by dragging the response curve about one the display within the filter plugins. * Some RDF updates + ladspa URN as per http://lists.lv2plug.in/pipermail/devel-lv2plug.in/2009-June/000226.html + Added extended port properties to rdf (log) * Numerous tweaks/improvements. People using lv2rack version 4 should upgrade to version 5 before using this release as I've backed out a workaround from version 1.0.1 which was done just to support version 4 of lv2rack. Download is here: http://www.invadarecords.com/Downloads.php?ID=00000264 Ubuntu packages here: https://launchpad.net/~invada/+archive/ppa cheers, Fraser -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFKUJanNZroiEh4erwRAr6ZAJ9CDgBrY7Q4ENIH3ymrmma7YJym6QCfc08b 17B/ZGMUvHgedRZ6CnMHK1g= =JCt2 -----END PGP SIGNATURE-----

16 years, 5 months

help on creating MIDI from linux input events

by Renato Budinich

Hello to all, I would like to write a program which does the following: detect the input events generated by a usb device which i own - the Rig Kontrol 2 from Native Instruments which is a pedal board intended for guitar use and which already has a linux driver - and trigger with those midi messages; i.e, pushing a button would create a midi note on/off, rolling the pedal a midi CC. As said, the pedal produces already linux input events so it would be a matter of creating a midi client (jack or alsa), grab these events and create midi from them. I would then use these midi messages to control Jack applications (mostly rakarrack) My C/programming knowledge is basic, so I ask your advice: 1) would it be easier to achieve this through jack or alsa? I'm confused here because jack applications i use - hydrogen for example - for what concerns midi, they all appear under the ALSA tab in qjackctl's Connection window. Are they really alsa midi clients being wrapped by jack? Is there a reason for writing alsa midi clients instead of native jack midi clients? So my problem is if i should learn the jack api or the alsa one. 2) Once I've decided on 1), which is the best place to document myself? I would prefer, if possible, to learn only what i need for this simple project - which for me btw is anything but simple. I mean not learning the whole jack or alsa api if i'm only going to use the basics. I really want to do this, but as you can see it's a difficult project for me. It would be wonderful if someone could give me kind of detailed advice on what "bricks" i'll need: relevant functions from the apis, general code structure and well, anything that will make me life easier :) thank you, Renato

16 years, 5 months

Version 0.2 of uli-plugins

by Ulrich Lorenz Schlüter

Hi, I released version 0.2 of uli-plugins a series of LV2 plugins. I added some latches and flipflops. http://sourceforge.net/projects/uli-plugins/ Regards Uli

16 years, 5 months

Re: [LAD] help on creating MIDI from linux input events

by nescivi

I guess this was meant to go to the list :) On Monday 06 July 2009 12:25:31 you wrote: > On Sun, 2009-07-05 at 15:25 -0400, nescivi wrote: > > It might be an overkill, but something like this is very easily done with > > SuperCollider (or Chuck or Pd for that matter). > > > > sincerely, > > Marije > > So it seems I'll go the SuperCollider way, as it is a very powerful > audio-oriented language and has already a class, GeneralHID, meant to do > exactly what i meant. It will be easy. Also, doing this inside > SuperCollider will allow me to do much more fun audio-things with my > pedal AND with other devices than just sending out midi. > > Thank all of you for the great replies! > > cheers > Renato

16 years, 5 months

Alesis AudioLink

by Michał Kloch

Hi. Has anybody tried one of the Alesis AudioLink usb cables with Linux? You can see the product here: http://www.alesis.com/audiolink They say you need no drivers to use it with Windows or Mac, any idea if that's the same with Linux? I'm using Ubuntu at the moment.

16 years, 5 months

uli-plugins 0.1 release - A series of LV2 plugins

by Ulrich Lorenz Schlüter

Hi, I proudly released version 0.1 of uli-plugins, a collection of LV2 plug ins. ULI is the abbreviation for *U*lis-*L*v2-*I*nserts. The release contains a simple series of logic gates. Namely an AND, NAND, OR, NOR, XOR, XNOR and a NOT. It's hosted on sourceforge: http://uli-plugins.sourceforge.net Regards Uli

16 years, 5 months

Re: [LAD] help on creating MIDI from linux input events

by Renato Budinich

On Sun, 2009-07-05 at 00:51 +0200, Robert Jonsson wrote: > Hi Renato, > > maybe I misunderstand you someway but does this driver not already > produce midi? If not what does it produce, keyboard events? > If it's midi, which I would suspect, then it should just be a matter > och getting Rakarrack to recognize these messages, hence, hacking on > Rakarrack. > > /Robert nope, it produces keyboard events, precisely KEY_1 through KEY_7 and the pedal produces EV_ABS

16 years, 5 months

Re: [LAD] help on creating MIDI from linux input events

by Miguel Morales

Hmm, so you're saying that the device sends keyboard events. How did you find out which kind of data it sends out? Sending out midi note events is easy with RTMidi, check out the section on midi out section. It contains a section on MIDI note output. I don't have much experience on grabbing keyboard type events using a daemon. I would recommend finding a cross platform solution. If not try finding out how to read keyboard events while being a daemon. Like a keylogger I guess. C++ isn't much of a jump from C so it should be easy to pick up and go. On Jul 5, 2009 3:53 AM, "Renato Budinich" <rennabh(a)gmail.com> wrote: Thank you very much, this is interesting, I'll have a look into RtMidi and your program. Being that the little I know is C, is it much more difficult outputting notes using the alsa api? > > Since there is a driver for it, you should be able to use it as an > alsa midi device. uhm, i'm not sure... the driver (snd_usb_caiaq) actually takes care of the soundcard built in the pedal, and on the way also makes the buttons create keyboard events, and the pedal EV_ABS

16 years, 5 months

Re: [LAD] help on creating MIDI from linux input events

by Ralf Mardorf

I wrote: > Subject: Re: [LAD] help on creating MIDI from linux input events > Date: Sun, 05 Jul 2009 13:11:35 +0200 > From: Ralf Mardorf > To: Renato Budinich > CC: linux-audio-dev(a)lists.linuxaudio.org > > > > Renato Budinich wrote: > > Thank you very much, this is interesting, I'll have a look into RtMidi > > and your program. Being that the little I know is C, is it much more > > difficult outputting notes using the alsa api? > > > > > > > >> Since there is a driver for it, you should be able to use it as an > >> alsa midi device. > >> > > uhm, i'm not sure... the driver (snd_usb_caiaq) actually takes care of > > the soundcard built in the pedal, and on the way also makes the buttons > > create keyboard events, and the pedal EV_ABS > > > > Hi :) > > I'm not a Linux, neither a C/C++ coder, but the answer here is very > simple, if the MIDI events (I guess this is what you mean by keyboard > events) are recognized by Linux, then there seems to be a driver for > your equipment that's good enough for your needs :). So go on, write a > simple Linux MIDI tool in C/C++, make it open source and reach in And English also isn't my language ;). Maybe you like to 'hand in' a link. > the > link, maybe some Dino-Assembler-Beings for some microchips (like me) > will be able to understand how to program for Linux too, if there would > be some very simple examples, excepted of "Hello world" ;). > > Good luck, > Ralf

16 years, 5 months

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Linux-audio-dev