Linux-audio-user

linux-audio-user@lists.linuxaudio.org

3 participants
20662 discussions

by worik

Friends Not Linux specific. I am involved in the design of one, and renovation of another, space for performing amplified music. I have been looking for advice on acoustic design. In both cases there is nothing I can do about the basic external shape but in both cases I have a lot of control over the internal lining design. Acoustic isolation is important, and I can find advice on that (plenty) on the web. But what I cannot find is advice on how to make it sound good inside. The b3est advice I have had was a throwaway comment about avoiding right angles, and it seems logical to me to avoid parrallel walls that can support a standing wave and be susceptible to resonance. But beyond that I am a bit at sea. Is there any place on the web that documents best practice for some one in this position? Worik -- If not me then who? If not now then when? If not here then where? So, here I stand, I can do no other root(a)worik.org 021-1680650, (03) 4821804 Aotearoa (New Zealand)

7 years, 10 months

Re: [LAU] [Rosegarden-user] RG 17.04 seems to leave lock files behind

by david

On 01/10/2018 07:59 AM, Will Godfrey wrote: > On Wed, 10 Jan 2018 08:40:55 -0500 > Ted Felix <ted(a)tedfelix.com> wrote: > >> On 01/10/2018 02:46 AM, david wrote: >>> Was completely unable to duplicate the problem. >>> >>> Must have been the phases of the moon or something. Thanks for fixing it >>> quantum-mechanics-style simply by turning your attention toward it! :) >> >> Ha! Computers are afraid of me. >> >> Lock file problems tend to happen when rg crashes. My best guess is >> that it was crashing when it was going down and now it isn't. >> >> Ted. >> > > Another way that's caught me (rather more often than I'd like to admit) is > shutting down the desktop, without first shutting down Rosegarden. Didn't do that! > Wasn't there some discussion on adding some kind of time stamp to the lock > file, so that it will ignore one that was (say) over 24 hour old. I don't remember if there was a timestamp in the orphaned lockfile, but it clearly wouldn't have been over 24 hours old. -- David W. Jones gnome(a)hawaii.rr.com authenticity, honesty, community http://dancingtreefrog.com

7 years, 10 months

Re: [LAU] How to get started writing a JACK app? (also what distro for BeagleBone)

by Paul Davis

On Wed, Jan 10, 2018 at 3:48 PM, Andrew Voelkel <jandyman.voelkel(a)gmail.com> wrote: > Glad to hear the discussion. From an outsider’s point of view, there are > few things I don’t get. > > > > First, if each JACK app is a separate process, then theoretically you have > to do a bunch of expensive process context switches for each audio buffer. > In the scheme of things, a context switch is typically not very expensive compared to a typical audio buffer size (say 16 samples and up). The only way it gets unusually expensive is if a process touches a lot of memory during its execution. This isn't impossible in an audio/DSP context, but it isn't very likely either. > And then there is interprocess communication. Uses shared memory buffers? > it's all in shared memory. there's no communication overhead. As opposed to a typical plug-in architecture where everything runs under > the host process. It is amazing to me that an interprocess scheme wouldn’t > run into major problems under compute load when running with the small > buffers needed for low latency. > be amazed :) > > > What am I missing here? > > > > The other thing I’m used to seeing in a plug in API is setup for buffer > sizes, sample rates, audio IO. The host centralizes this process. > JACK does the same thing. Each client has no control over those things (at least, not in the normal way). They can ask to change the buffer size, but their request may be ignored, or it may be reset by something else. Just like in a plugin architecture. Then there is advertising your pins and capabilities. I was mystified when > looking at the simple JACK examples that I didn’t see code for dealing with > these issues (e.g. being sample rate aware). > JACK clients have only one thing of interest to other clients: ports. These are all clearly visible, and tagged appropriately (though for most clients, there's almost no tagging to do)

7 years, 10 months

Re: [LAU] How to get started writing a JACK app? (also what distro for BeagleBone)

by Paul Davis

As Benoit suggested, there are plugin APIs on Linux too (both LV2 and LinuxVST). If you would write an AU for MacOS, you could write a plugin on Linux too. There are plentiful hosts, some of them extremely lightweight (i.e. they don't really do anything themselves). Normal JACK clients introduce a tiny amount of overhead and add no latency whatsoever. It is quite common (unfortunately in my view these days) to implement things as JACK clients (i.e. standalone programs) on Linux, rather than as plugins (though this changing). On Tue, Jan 9, 2018 at 11:07 PM, Andrew Voelkel <jandyman.voelkel(a)gmail.com> wrote: > Hi, > > > > Maybe I need to ask a different question. My goal is to stick my real time > processing algorithm in between x number of audio inputs coming from a USB > audio interface, and then send the outputs to y number of audio outputs on > the same USB audio interface. Low latency is important. Being able to add > in other processing from third parties would be nice, but it isn’t > essential. > > > > Is writing a JACK client the right way to do this? If so, what is the > right approach? If not, what is the right way to do this? > > > > On the Apple platform, I do this by writing an Audio Unit, and either > leverage a DAW host application like Logic or the Apple AVAudioEngine to > serve as a host for my processing algorithm. The host gets the inputs from > the audio interface, I process the audio in my Audio Unit in a callback > routine, and the host sends the outputs to the audio interface. In Windows > a similar thing happens, but with VST plugins and an ASIO host, which is > either a DAW or a custom ASIO host. I’ve done both. > > > > So what is the best “linux way” to do this? Out-of-process seems high > overhead and not suited for low latency, so I figure I must be > misunderstanding something quite fundamental. > > > > Thanks so much for the help, I really do appreciate it. > > > > - Andy > > > > *From: *Paul Davis <paul(a)linuxaudiosystems.com> > *Date: *Tuesday, January 9, 2018 at 8:22 PM > *To: *Andrew Voelkel <jandyman.voelkel(a)gmail.com> > *Cc: *Benoît Rouits <brouits(a)free.fr>, linux-audio-user < > linux-audio-user(a)lists.linuxaudio.org> > *Subject: *Re: [LAU] How to get started writing a JACK app? (also what > distro for BeagleBone) > > > > In-process JACK clients are a very special case and almost nobody > implements or uses them. They are like plugins for the JACK server, and > that's not really the point of JACK (which was designed to connect distinct > processes). > > Look at the out-of-process ("normal") example(s) instead. > > > > On Tue, Jan 9, 2018 at 9:39 PM, Andrew Voelkel <jandyman.voelkel(a)gmail.com> > wrote: > > Hi and thanks. > > > > So looking at the in-process example, I’m guessing it compiles to a > dynamic library which the server loads? If so, how does the server know the > capabilities of the in-process client. > > > > I’m coming from writing VST plug-ins on Windows or Audio Units on Apple > platforms, in case I sound confused. > > > > I’m also having trouble getting used to the idea of the client being the > plug in, normally I would think the client would be what is called the > “host” on Windows or Apple, and the plug-in would closer to a “server”. But > here the terminology is reversed. Am I understanding correctly? The > “client” in JACK is the plug-in (for in-process use), correct? > > > > Finally, I’d like to get started seeing whether the eco-system works for > low latency with existing apps and components for diving in. Is AVLinux the > way to go, and is there any reason it will not work on BeagleBone? > > > > I’m not a Linux expert in case you can’t already tell! It’s not that I > have zero experience, but sometimes it’s close, depending on context. > > > > But I do know audio, and operating system design, and threading, and SIMD, > and etc. > > > > - Andy > > > > *From: *Linux-audio-user <linux-audio-user-bounces(a)lists.linuxaudio.org> > on behalf of Paul Davis <paul(a)linuxaudiosystems.com> > *Date: *Tuesday, January 9, 2018 at 4:41 PM > *To: *Benoît Rouits <brouits(a)free.fr> > *Cc: *linux-audio-user <linux-audio-user(a)lists.linuxaudio.org> > *Subject: *Re: [LAU] How to get started writing a JACK app? > > > > please. not sourceforge. > > JACK code lives on github ... https://github.com/jackaudio/ > example-clients > > > > On Tue, Jan 9, 2018 at 6:21 PM, Benoît Rouits <brouits(a)free.fr> wrote: > > Hello Andy > > as a starting point, you could look at: > > http://jackit.sourceforge.net/cgi-bin/lxr/http/source/example-clients/ > > This is C client code samples for jack. > > HTH, > Benoît > > Le 09/01/2018 à 16:19, Andrew Voelkel a écrit : > > > > Hi,____ > > > > __ __ > > > > I’m new to this list. I’m thinking of giving low latency real time > > audio in Linux another try after my last unsuccessful attempt a few > > years ago. My goal is to put some of my own DSP code into a hardware > > appliance and use it to process audio signals during music > > rehearsals and performances.____ > > > > __ __ > > > > I think this boils down to getting an appropriate distro, getting > > JACK working in a low latency configuration with a multichannel USB > > interface. And then …____ > > > > __ __ > > > > Writing a JACK app to process the audio. ____ > > > > __ __ > > > > I’ve done some googling and found a lot about _/using/_ JACK, but > > not much about writing a JACK app. ____ > > > > __ __ > > > > Are there any examples or tutorials out there?____ > > > > __ __ > > > > I’m already up to speed on doing C++ cross development with > Eclipse.____ > > > > __ __ > > > > I’ve got a BeagleBone black sitting around here I could use to > > experiment.____ > > > > __ __ > > > > * Andy____ > > > > > > > > > > > _______________________________________________ > > Linux-audio-user mailing list > > Linux-audio-user(a)lists.linuxaudio.org > > https://lists.linuxaudio.org/listinfo/linux-audio-user > > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user(a)lists.linuxaudio.org > https://lists.linuxaudio.org/listinfo/linux-audio-user > > > > _______________________________________________ Linux-audio-user mailing > list Linux-audio-user(a)lists.linuxaudio.org https://lists.linuxaudio.org/ > listinfo/linux-audio-user > > >

7 years, 10 months

Does jackd sits on top of ALSA ?

by jonetsu

I've been using jackd fro years and will not change. I have a question which is not important at all.. does jackd sits on top of ALSA or besides it ? In other words can a Linux audio system work with only jackd ? If not, what is the responsibility of ALSA in a system using jackd ? Cheers.

7 years, 10 months

Increased single-box JACK performance using multiple servers, summary and status

by Jonathan E. Brickman

It is finally working, and in very repeatable fashion, three "soft" servers feeding to one connecting to real audio hardware. Test mode only so far. Next step is automated startup. Details: https://github.com/jebofponderworthy/MultiJACK/blob/master/README.md -- Jonathan E. Brickman jeb(a)ponderworthy.com (785)233-9977 Hear us at http://ponderworthy.comcom -- CDs and MP3 now available! Music of compassion; fire, and life!!!

7 years, 10 months

Re: [LAU] How to get started writing a JACK app? (also what distro for BeagleBone)

by Benoît Rouits

I'm not an expert, but if you are looking something like AU or VST, maybe you should consider writing an LV2 plugin (most of linux DAWs can host LV2 plugins). An LV2 plugin is a small shared object with a few callbacks to process sound or midi, or controls. They can have a graphical interface too, but this is not mandatory. main entry point url is there : http://lv2plug.in/ Cheers, Benoît Le 10/01/2018 à 05:07, Andrew Voelkel a écrit : > Hi, > > > > Maybe I need to ask a different question. My goal is to stick my real > time processing algorithm in between x number of audio inputs coming > from a USB audio interface, and then send the outputs to y number of > audio outputs on the same USB audio interface. Low latency is important. > Being able to add in other processing from third parties would be nice, > but it isn’t essential. > > > > Is writing a JACK client the right way to do this? If so, what is the > right approach? If not, what is the right way to do this? > > > > On the Apple platform, I do this by writing an Audio Unit, and either > leverage a DAW host application like Logic or the Apple AVAudioEngine to > serve as a host for my processing algorithm. The host gets the inputs > from the audio interface, I process the audio in my Audio Unit in a > callback routine, and the host sends the outputs to the audio interface. > In Windows a similar thing happens, but with VST plugins and an ASIO > host, which is either a DAW or a custom ASIO host. I’ve done both. > > > > So what is the best “linux way” to do this? Out-of-process seems high > overhead and not suited for low latency, so I figure I must be > misunderstanding something quite fundamental. > > > > Thanks so much for the help, I really do appreciate it. > > > > * Andy > > > > *From: *Paul Davis <paul(a)linuxaudiosystems.com> > *Date: *Tuesday, January 9, 2018 at 8:22 PM > *To: *Andrew Voelkel <jandyman.voelkel(a)gmail.com> > *Cc: *Benoît Rouits <brouits(a)free.fr>, linux-audio-user > <linux-audio-user(a)lists.linuxaudio.org> > *Subject: *Re: [LAU] How to get started writing a JACK app? (also what > distro for BeagleBone) > > > > In-process JACK clients are a very special case and almost nobody > implements or uses them. They are like plugins for the JACK server, and > that's not really the point of JACK (which was designed to connect > distinct processes). > > Look at the out-of-process ("normal") example(s) instead. > > > > On Tue, Jan 9, 2018 at 9:39 PM, Andrew Voelkel > <jandyman.voelkel(a)gmail.com <mailto:jandyman.voelkel@gmail.com>> wrote: > > Hi and thanks. > > > > So looking at the in-process example, I’m guessing it compiles to a > dynamic library which the server loads? If so, how does the server > know the capabilities of the in-process client. > > > > I’m coming from writing VST plug-ins on Windows or Audio Units on > Apple platforms, in case I sound confused. > > > > I’m also having trouble getting used to the idea of the client being > the plug in, normally I would think the client would be what is > called the “host” on Windows or Apple, and the plug-in would closer > to a “server”. But here the terminology is reversed. Am I > understanding correctly? The “client” in JACK is the plug-in (for > in-process use), correct? > > > > Finally, I’d like to get started seeing whether the eco-system works > for low latency with existing apps and components for diving in. Is > AVLinux the way to go, and is there any reason it will not work on > BeagleBone? > > > > I’m not a Linux expert in case you can’t already tell! It’s not that > I have zero experience, but sometimes it’s close, depending on context. > > > > But I do know audio, and operating system design, and threading, and > SIMD, and etc. > > > > * Andy > > > > *From: *Linux-audio-user > <linux-audio-user-bounces(a)lists.linuxaudio.org > <mailto:linux-audio-user-bounces@lists.linuxaudio.org>> on behalf of > Paul Davis <paul(a)linuxaudiosystems.com > <mailto:paul@linuxaudiosystems.com>> > *Date: *Tuesday, January 9, 2018 at 4:41 PM > *To: *Benoît Rouits <brouits(a)free.fr <mailto:brouits@free.fr>> > *Cc: *linux-audio-user <linux-audio-user(a)lists.linuxaudio.org > <mailto:linux-audio-user@lists.linuxaudio.org>> > *Subject: *Re: [LAU] How to get started writing a JACK app? > > > > please. not sourceforge. > > JACK code lives on github ... > https://github.com/jackaudio/example-clients > > > > On Tue, Jan 9, 2018 at 6:21 PM, Benoît Rouits <brouits(a)free.fr > <mailto:brouits@free.fr>> wrote: > > Hello Andy > > as a starting point, you could look at: > > http://jackit.sourceforge.net/cgi-bin/lxr/http/source/example-clients/ > > This is C client code samples for jack. > > HTH, > Benoît > > Le 09/01/2018 à 16:19, Andrew Voelkel a écrit : > > > > Hi,____ > > > > __ __ > > > > I’m new to this list. I’m thinking of giving low latency > real time > > audio in Linux another try after my last unsuccessful > attempt a few > > years ago. My goal is to put some of my own DSP code into > a hardware > > appliance and use it to process audio signals during music > > rehearsals and performances.____ > > > > __ __ > > > > I think this boils down to getting an appropriate distro, > getting > > JACK working in a low latency configuration with a > multichannel USB > > interface. And then …____ > > > > __ __ > > > > Writing a JACK app to process the audio. ____ > > > > __ __ > > > > I’ve done some googling and found a lot about _/using/_ > JACK, but > > not much about writing a JACK app. ____ > > > > __ __ > > > > Are there any examples or tutorials out there?____ > > > > __ __ > > > > I’m already up to speed on doing C++ cross development > with Eclipse.____ > > > > __ __ > > > > I’ve got a BeagleBone black sitting around here I could use to > > experiment.____ > > > > __ __ > > > > * Andy____ > > > > > > > > > > > _______________________________________________ > > Linux-audio-user mailing list > > Linux-audio-user(a)lists.linuxaudio.org > <mailto:Linux-audio-user@lists.linuxaudio.org> > > https://lists.linuxaudio.org/listinfo/linux-audio-user > > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user(a)lists.linuxaudio.org > <mailto:Linux-audio-user@lists.linuxaudio.org> > https://lists.linuxaudio.org/listinfo/linux-audio-user > > > > _______________________________________________ Linux-audio-user > mailing list Linux-audio-user(a)lists.linuxaudio.org > <mailto:Linux-audio-user@lists.linuxaudio.org> > https://lists.linuxaudio.org/listinfo/linux-audio-user > > >

7 years, 10 months

Re: [LAU] How to get started writing a JACK app? (also what distro for BeagleBone)

by Paul Davis

In-process JACK clients are a very special case and almost nobody implements or uses them. They are like plugins for the JACK server, and that's not really the point of JACK (which was designed to connect distinct processes). Look at the out-of-process ("normal") example(s) instead. On Tue, Jan 9, 2018 at 9:39 PM, Andrew Voelkel <jandyman.voelkel(a)gmail.com> wrote: > Hi and thanks. > > > > So looking at the in-process example, I’m guessing it compiles to a > dynamic library which the server loads? If so, how does the server know the > capabilities of the in-process client. > > > > I’m coming from writing VST plug-ins on Windows or Audio Units on Apple > platforms, in case I sound confused. > > > > I’m also having trouble getting used to the idea of the client being the > plug in, normally I would think the client would be what is called the > “host” on Windows or Apple, and the plug-in would closer to a “server”. But > here the terminology is reversed. Am I understanding correctly? The > “client” in JACK is the plug-in (for in-process use), correct? > > > > Finally, I’d like to get started seeing whether the eco-system works for > low latency with existing apps and components for diving in. Is AVLinux the > way to go, and is there any reason it will not work on BeagleBone? > > > > I’m not a Linux expert in case you can’t already tell! It’s not that I > have zero experience, but sometimes it’s close, depending on context. > > > > But I do know audio, and operating system design, and threading, and SIMD, > and etc. > > > > - Andy > > > > *From: *Linux-audio-user <linux-audio-user-bounces(a)lists.linuxaudio.org> > on behalf of Paul Davis <paul(a)linuxaudiosystems.com> > *Date: *Tuesday, January 9, 2018 at 4:41 PM > *To: *Benoît Rouits <brouits(a)free.fr> > *Cc: *linux-audio-user <linux-audio-user(a)lists.linuxaudio.org> > *Subject: *Re: [LAU] How to get started writing a JACK app? > > > > please. not sourceforge. > > JACK code lives on github ... https://github.com/jackaudio/ > example-clients > > > > On Tue, Jan 9, 2018 at 6:21 PM, Benoît Rouits <brouits(a)free.fr> wrote: > > Hello Andy > > as a starting point, you could look at: > > http://jackit.sourceforge.net/cgi-bin/lxr/http/source/example-clients/ > > This is C client code samples for jack. > > HTH, > Benoît > > Le 09/01/2018 à 16:19, Andrew Voelkel a écrit : > > > > Hi,____ > > > > __ __ > > > > I’m new to this list. I’m thinking of giving low latency real time > > audio in Linux another try after my last unsuccessful attempt a few > > years ago. My goal is to put some of my own DSP code into a hardware > > appliance and use it to process audio signals during music > > rehearsals and performances.____ > > > > __ __ > > > > I think this boils down to getting an appropriate distro, getting > > JACK working in a low latency configuration with a multichannel USB > > interface. And then …____ > > > > __ __ > > > > Writing a JACK app to process the audio. ____ > > > > __ __ > > > > I’ve done some googling and found a lot about _/using/_ JACK, but > > not much about writing a JACK app. ____ > > > > __ __ > > > > Are there any examples or tutorials out there?____ > > > > __ __ > > > > I’m already up to speed on doing C++ cross development with > Eclipse.____ > > > > __ __ > > > > I’ve got a BeagleBone black sitting around here I could use to > > experiment.____ > > > > __ __ > > > > * Andy____ > > > > > > > > > > > _______________________________________________ > > Linux-audio-user mailing list > > Linux-audio-user(a)lists.linuxaudio.org > > https://lists.linuxaudio.org/listinfo/linux-audio-user > > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user(a)lists.linuxaudio.org > https://lists.linuxaudio.org/listinfo/linux-audio-user > > > > _______________________________________________ Linux-audio-user mailing > list Linux-audio-user(a)lists.linuxaudio.org https://lists.linuxaudio.org/ > listinfo/linux-audio-user >

7 years, 10 months

Example setup for zita-njbridge in multicast mode?

by Jonathan E. Brickman

Do you have a working zita-njbridge <http://kokkinizita.linuxaudio.org/linuxaudio/> triplet of command lines (one n2j, two j2n) proven to run in multicast mode, which you might share? I'd like to study a working example, to compare to my special case, where I'm running them all in one machine, with three separate JACK servers, only the first one being connected to real hardware. I have zita-njbridge working just fine in one-to-one mode, but if I try the following triplet (SOFT1 and SOFT2 are additional JACK servers): |zita-n2j 239.255.0.10 55555 enp0s25 zita-j2n --jserv SOFT1 239.255.0.10 55555 enp0s25 ita-j2n --jserv SOFT2 239.255.0.10 55555 enp0s25 | the NIC item is not reported as extra, but the second j2n is still blocked, it's still running in one-to-one mode; this is proven because if the first one is killed, the second one automatically connects. The same occurs if I run each in its own firejail <https://firejail.wordpress.com/>, all of them being given their own IPs connected to the same dummy NIC. -- /Jonathan E. Brickmanjeb(a)ponderworthy.com <http://login.jsp/?at=02e47df3-a9af-4cd9-b951-1a06d255b48f&mailto=jeb@ponder…> (785)233-9977/ /Hear us at http://ponderworthy.com -- CDs and MP3s now available! <http://ponderworthy.com/ad-astra/ad-astra.html>/ /Music of compassion; fire, and life!!!/

7 years, 10 months

Re: [LAU] How to get started writing a JACK app?

by Andrew Voelkel

> Hi, > > > > I’m new to this list. I’m thinking of giving low latency real time audio > in Linux another try after my last unsuccessful attempt a few years ago. My > goal is to put some of my own DSP code into a hardware appliance and use it > to process audio signals during music rehearsals and performances. > > > > I think this boils down to getting an appropriate distro, getting JACK > working in a low latency configuration with a multichannel USB interface. > And then … > > > > Writing a JACK app to process the audio. > > > > I’ve done some googling and found a lot about _*using*_ JACK, but not > much about writing a JACK app. > > > > Are there any examples or tutorials out there? > > > > I’m already up to speed on doing C++ cross development with Eclipse. > > > > I’ve got a BeagleBone black sitting around here I could use to experiment. > > > > - Andy > >

7 years, 10 months

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Linux-audio-user