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JACK session API in Perl, Python, Ruby, and Lua

by Joel Roth

https://github.com/navicore/Jacks Includes sample code for several languages. Developed by Ed Sweeney -- Joel Roth

13 years, 3 months

Updates

by Fons Adriaensen

Updates available now at <http://kokkinizita.linuxaudio.org/linuxaudio/downloads> zita-alsa-pcmi-0.2.0 * Now includes some dirty hacks (implemented via the debug options parameter so they don't clutter the API) to support the -L option of zita-ajbridge-0.2.2 * Fixed the bug that made it fail with Jack period sizes >= 1024 (filter coefficients going out of range). * Added some hacks, activiated by the -L option, to make it work with ALSA's loop devices. The latter requires some clarification. The two apps provided by zita-ajbridge were never intented to be used with the ALSA loop devices. They were developed to provide additional and full quality capture or playback channels to Jack, using a real soundcard. Yet most people trying the first release used them with the loop devices, to provide a Jack interface to some misbehaving apps such as flash player or skype. Using the loop device is required since those apps refuse to work with ALSA's Jack plugin. It's a dirty hack using an unwanted resampling step, but it seems there is no working alternative. The ALSA loop devices presents themselves as hw: devices, but they don't behave like a real one: * Timing of period wakeups is quantised to a much too high value, and produces lots of jitter, worse than even the most crappy USB interface. It also makes using the device with small period sizes impossible, as wakeups occur when it's almost too late. The next cycle will xrun in that case. * The loop devices have 32 channels. They allow to be opened with a different channel count at both ends, but then make a mess of it. For example mplayer's two channels will be spread out over the available 32, making it run at 16 times normal speed. To run zita-a2j or zita-j2a with the ALSA loop device: * Use the -L option. This forces two things: the sample format will be 16-bit, and the device is opened in 2-channel mode. This makes it usable to apps at the other end which can't deal with floats or more than 2 channels. Note that just using -c 2 (which is also the default) still opens the ALSA device with all its channels, as must be done on a real hw: device, so that won't work. * Use at least -p 256 -n 3, or -p 512 or higher (on the ALSA device - Jack's parameters don't matter). Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

13 years, 3 months

Timing of the ALSA loop device

by Fons Adriaensen

Hello, Does anyone know what sort of timer is used by the ALSA loop device, and if this can be changed in some way ? On the system I'm working on now, wakeup times while waiting for a period to be available (as done by Jack and zita-alsa-pcmi) seem to be quantised in steps of 3.3ms or so. Which means it sometimes wakes up 3/4 or more of a period too late. Next one will be xrun in that case. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

13 years, 3 months

First release of zita-ajbridge

by Fons Adriaensen

Hello all, The first official release of zita-ajbridge is now available at <http://kokkinizita.linuxaudio.org/linuxaudio/downloads>. Quoting the README: This package provides two applications, zita-a2j and zita-j2a. They allow to use an ALSA device as a Jack client, to provide additional capture (a2j) or playback (j2a) channels. Functionally these are equivalent to the alsa_in and alsa_out clients that come with Jack, but they provide much better audio quality. The resampling ratio will typically be stable within 1 PPM and change only very smoothly. Delay will be stable as well even under worse case conditions, e.g. the Jack client running near the end of the cycle. You will also need the latest zita-resampler and zita-alsa-pcmi libraries. All feedback welcome. Ciao, -- FA Vor uns liegt ein weites Tal, die Sonne scheint - ein Glitzerstrahl.

13 years, 3 months

Re: [LAD] [Jack-Devel] First release of zita-ajbridge

by Stéphane Letz

Le 19 mars 2012 à 16:25, Nedko Arnaudov a écrit : > Stéphane Letz <letz(a)grame.fr> writes: > >> Le 19 mars 2012 à 16:15, Nedko Arnaudov a écrit : >> >>> Stéphane Letz <letz(a)grame.fr> writes: >>> >>>> Le 19 mars 2012 à 15:20, Fons Adriaensen a écrit : >>>> >>>>> On Mon, Mar 19, 2012 at 01:19:25PM +0100, Stéphane Letz wrote: >>>>> >>>>>> I'm wondering how your code could replace the "adapter" mechanism >>>>>> that I did in JACK2 for that never worked fully >>>>>> reliably. Basically the "adapter" idea is a bit more general in >>>>>> the sense that it aims at "adapting" streams in different >>>>>> context: like network <==> Audio API (CoreAudio for OSX, ALSA for >>>>>> Linux, PortAudio for Windows...), or several ALSA devices..etc.. >>>>>> (The adapters are also developed as "in server" clients, this >>>>>> make a bit more easy to add them in a running session using >>>>>> "ladish" kind of studio management approaches...) >>> In fact, ladish doesnt manage in-server clients at all. It can only >>> restore jack settings, and they could include stuff like in-process >>> clients and slave drivers. jackdbus provides engine parameter for >>> the latter but doesnt for the former. >>> >>> -- >> >> Well there is a control API to load/unload in-sever client. I was >> thinking this API could be used with ladish... > > ladish could be made to use this API. But it is not the case. At least > not yet. > > -- > Nedko Arnaudov <GnuPG KeyID: 5D1B58ED> Well this could be interesting to have access to "netjack2" components : netmanager, netadapter, audioadapters.... Stéphane

13 years, 3 months

Re: [LAD] First release of zita-ajbridge

by Fons Adriaensen

On Mon, Mar 19, 2012 at 06:58:29PM +0100, Robin Gareus wrote: > # mplayer -ao alsa,device=hw=1,0 some_music.wav > # zita-a2j -dhw:1,1 > > I get endless messages: > Starting synchronisation. > Detected excessive timing errors, waiting 15 seconds. > This may happen with current Jack1 after freewheeling. (meanwhile I'm back home, the loopback device is hw:3 here) [terminal 1] fons@zita1:/audio/audiofiles/tracks> mplayer -ao alsa:device=hw=3.1 diana-krall-almost-blue-44.wav MPlayer SVN-r34426-4.6.2 (C) 2000-2011 MPlayer Team 181 audio & 384 video codecs mplayer: could not connect to socket mplayer: No such file or directory Failed to open LIRC support. You will not be able to use your remote control. Playing diana-krall-almost-blue-44.wav. Audio only file format detected. Load subtitles in ./ ========================================================================== Opening audio decoder: [pcm] Uncompressed PCM audio decoder AUDIO: 44100 Hz, 2 ch, s16le, 1411.2 kbit/100.00% (ratio: 176400->176400) Selected audio codec: [pcm] afm: pcm (Uncompressed PCM) ========================================================================== AO: [alsa] 44100Hz 2ch s16le (2 bytes per sample) Video: no video Starting playback... A: 4.0 (04.0) of 244.0 (04:04.0) 0.1% ... [terminal 2] fons@zita1:~> zita-a2j -d hw:3,0 -r 44100 Starting synchronisation /me makes connections in qjackctl and hears lovely piano intro... So this just works. I do indeed have to start mplayer first, but only the first time. After that I can stop and restart mplayer without problem. This is probably some quirk of the loopback device. There is no such thing as 'requesting exclusive access' in the ALSA pcm API - it depends only on the device. > The message is repeated every ~15 sec; and it does not stop. > Each time a message is printed there's a short very jittery sound (I can > discern the music) but it remains silent for the remaining time. The silence is intentional - the app waits for the dust to settle down after it has detected 'impossible' timing info from either Jack's DLL or from the one tracking the ALSA device. There was a bug in the loopback device - it returned the wrong type of event when using poll() in some cases. It's fixed in 1.0.24. That would certainly explain what you see. > How do you conduct this test? > > I assume that there is no other ALSA-client involved and you use the > loopback in float/32 mode, w/native samplerate. Zita-a2j and j2a use libzita-alsa-pmci to access ALSA devices. It uses exactly the same methods as Jack's backend - very early versions (libclalsadrv 7 years ago) were in fact a C++ copy of Jack's backend. That means that whatever works with Jack will work with zita-a2j and j2a or any of my apps using ALSA. AFAIK Jack doens't run well with dmix/dsnoop either. And anyway there's no reason to use them with Jack. To run the delay test (assuming hw:3 is the loopback device): [Terminal 1] zita-a2j -d hw:3,0 [Terminal 2] zita-j2a -d hw:3,1 [Terminal 3] jack_delay and make the required connections. The off-list reply was a typo - back on LAD now. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

13 years, 3 months

update of zita-ajbridge

by Fons Adriaensen

Hello all, A bugfix update of zita-ajbridge is now available at the usual place. Thanks to Robin Gareus who discovered the bug: the typical last-minute-after-testing-added-line-typo. In this case it meant that both apps would use the lowest resampling quality in all cases... Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

13 years, 3 months

Re: [LAD] [Jack-Devel] First release of zita-ajbridge

by Stéphane Letz

Le 19 mars 2012 à 16:15, Nedko Arnaudov a écrit : > Stéphane Letz <letz(a)grame.fr> writes: > >> Le 19 mars 2012 à 15:20, Fons Adriaensen a écrit : >> >>> On Mon, Mar 19, 2012 at 01:19:25PM +0100, Stéphane Letz wrote: >>> >>>> I'm wondering how your code could replace the "adapter" mechanism >>>> that I did in JACK2 for that never worked fully reliably. Basically >>>> the "adapter" idea is a bit more general in the sense that it aims >>>> at "adapting" streams in different context: like network <==> Audio >>>> API (CoreAudio for OSX, ALSA for Linux, PortAudio for Windows...), >>>> or several ALSA devices..etc.. (The adapters are also developed as >>>> "in server" clients, this make a bit more easy to add them in a >>>> running session using "ladish" kind of studio management >>>> approaches...) > > In fact, ladish doesnt manage in-server clients at all. It can only > restore jack settings, and they could include stuff like in-process > clients and slave drivers. jackdbus provides engine parameter for the > latter but doesnt for the former. > > -- Well there is a control API to load/unload in-sever client. I was thinking this API could be used with ladish... Stephane

13 years, 3 months

Re: [LAD] First release of zita-ajbridge

by Stéphane Letz

> ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 18 Mar 2012 21:22:28 +0000 > From: Fons Adriaensen <fons(a)linuxaudio.org> > Subject: [LAD] First release of zita-ajbridge > To: Linux Audio Users <linux-audio-user(a)lists.linuxaudio.org>, Linux > Audio Developers <linux-audio-dev(a)lists.linuxaudio.org> > Message-ID: <20120318212228.GA19153(a)linuxaudio.org> > Content-Type: text/plain; charset=us-ascii > > Hello all, > > The first official release of zita-ajbridge is now available at > <http://kokkinizita.linuxaudio.org/linuxaudio/downloads>. > > Quoting the README: > > This package provides two applications, zita-a2j and zita-j2a. > They allow to use an ALSA device as a Jack client, to provide > additional capture (a2j) or playback (j2a) channels. > Functionally these are equivalent to the alsa_in and alsa_out > clients that come with Jack, but they provide much better audio > quality. The resampling ratio will typically be stable within > 1 PPM and change only very smoothly. Delay will be stable as > well even under worse case conditions, e.g. the Jack client > running near the end of the cycle. > > You will also need the latest zita-resampler and zita-alsa-pcmi > libraries. > > All feedback welcome. > > Ciao, > > -- > FA Really interesting.... I'm wondering how your code could replace the "adapter" mechanism that I did in JACK2 for that never worked fully reliably. Basically the "adapter" idea is a bit more general in the sense that it aims at "adapting" streams in different context: like network <==> Audio API (CoreAudio for OSX, ALSA for Linux, PortAudio for Windows...), or several ALSA devices..etc.. (The adapters are also developed as "in server" clients, this make a bit more easy to add them in a running session using "ladish" kind of studio management approaches...) How complex do you think it would be? Thanks. Stéphane

13 years, 3 months

Announcing the first 'Hydrogen Spring Drum Kit Contest'

by thijs van severen

(apologies for cross posting) The Hydrogen team is excited to announce the first 'Hyrdogen Spring Drum Kit Contest' ! As you all know, a drum machine is only as good as the sounds it produces -no matter how many whistles and bells it boasts. Some time ago there was a small poll on the Hydrogen site asking the Hydrogen users (aka 'you' ;-) what feature they wanted more than anything else. The answer was clear : "more and better drum kits". The goal of this fun contest is simple : with your help we can expand Hydrogen's sound library with some great new drum kits, and since this is a contest there are some really neat prizes to win! So if you have been playing with samples and thinking about creating a drum kit, but then decided not to do so after all : now is the perfect time to push yourself and go that extra mile. Once it's done you'll feel so much better ;-) Or maybe you have already made a drum kit in the past but didn't think it was worth submitting? Think again and share your hard work with the rest of the world! Curious ? Check out the details on the contest page <http://hydrogen.popez.org/hcms/node/2035> Hope to hear from you soon ! The Hydrogen team

13 years, 3 months

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Linux-audio-dev