JackAudio July 2016

jackaudio@lists.linuxaudio.org

20 participants
12 discussions

[Jack-Devel] fractional frame rates for alsa_in and alsa_out

by Markus Grabner

Hi! A while ago I initiated work on a Linux driver for Line6 devices (now under sound/usb/line6 in the Linux kernel tree). Some of these devices have weird sample rates (39062.5Hz, derived from the 10MHz USB clock divided by 256). The alsa_in and alsa_out jack clients are convenient tools to use such Line6 devices together with more standardized hardware operating at, e.g., 48kHz. However, alsa_in only supports integer sample rates, and even after a couple of minutes, alsa_in doesn't detect the correct resampling factor 1.2288 (48000/39062.5), but still reports the initial approximated value 1.228816 (48000/39062). Admittedly, the error isn't too big, but is larger than the error of high-quality crystal oscillators. And, after all, why use an approximation if we know better? I modified alsa_in and alsa_out such that they accept a sample rate in floating point format (command line option "-r") and query the fractional sample rate from the ALSA driver to compute the initial estimation of the resampling factor (see attached patch). What do you think about this patch? Kind regards, Markus

8 years, 4 months

[Jack-Devel] netJACK2 with two nodes

by xan

Hello JACK community, I’m planning my new audio editing setup (both hard- and software) and before investing in hardware, I’d like to ask for advice. Here’s what I want to do: – Both computers run Linux. – On Computer A, I can browse the web and see Youtube videos, I can listen to MP3 files with Totem and I can do DAW stuff with Ardour. – Computer B does nothing more than getting all the sound output from A and feed it to the speaker through it’s soundcard. Here’s my theoretical approach: – Both computers run JACK. – A runs PulseAudio in top of JACK. – A runs with the net backend using netJACK2. – B has the Net Manager loaded which gets the audio from A and pipes it to the soundcard. – Every time I boot the two computers, they are ready to work. No daemons I have to launch manually, etc. I want the configuration to be done one time for all. I got my understanding of JACK through the network from here: https://github.com/jackaudio/jackaudio.github.com/wiki/WalkThrough_User_Net… And this site would also be my guide for setting up the thing. But I’m not a JACK expert at all. It’s the first time I’m doing something like this. So I want to make shure I got the basics right. And, maybe you now even a better step-by-step tutorial which does exactly what I want. So, I appreciate any comments on this. Bye, xan

8 years, 4 months

[Jack-Devel] Linking apps together from script

by james-rpf

Hi, I'm trying to get receive audio data from a USB software defined radio and pipe it through jack to alsa out and also to another app dl-fldigi. It's working (off a fashion) using this hacky script https://gist.github.com/jrobinson-uk/123daebd8ff58d636ba02da9dfd7f3e1 which basically starts the jack server starts the 3 apps to link (mplayer --> alsa_out --> dl-fldigi) links mplayer to alsa then also to dl-fldigi I have 2 questions: Some of the apps either crash occasionally (dl-fldigi) or their is a case for restarting them (mplayer), at the moment I have to recreate the connections each time an app closes. Is it possible to create the connections first and have them persist, then connect the apps when they are (re)started? Secondly I have some audio issues, there are fractional pauses every so often which make the audio had to decode, is there anything about piping through jack that could cause this, on something which might mitigate it? James -- View this message in context: http://jack-audio.10948.n7.nabble.com/Linking-apps-together-from-script-tp1… Sent from the Jackit mailing list archive at Nabble.com.

8 years, 5 months

[Jack-Devel] Help getting firewire soundcard working on OSX

by Kjetil Matheussen

Hi, A Radium user can't get sound out of his firewire soundcard. Here's the mail: " I seem to be too stupid to setup Jack OSX with Radium 4 in my OSX 10.9.4 system: I never hear anything. output 3+4 of radium are routed to system default 1+2, which should be my firewire audio interface. " Anyone knows what could be wrong?

8 years, 5 months

[Jack-Devel] sending jack output to pulse

by tom.r

hi. i am working with some virtual systems. i have a linux machine using pulse to output audio (i can't change this). i have a windows machine without sound. i followed this tutorial to stream audio from the windows to the linux machine: https://blogs.gentoo.org/mgorny/2015/01/16/surround-sound-over-network-with… my problem is: the linux machine is also virtual and has no alsa device. all audio is send per pulse to the real audio output (as already mentioned, i can't change this). my question: how can i configure jack to send its output to pulse? (i know, normally people do this the other way around) i am grateful for any hints. -tom ------------------------------------------------- ONLY AT VFEmail! - Use our Metadata Mitigator to keep your email out of the NSA's hands! $24.95 ONETIME Lifetime accounts with Privacy Features! 15GB disk! No bandwidth quotas! Commercial and Bulk Mail Options!

8 years, 5 months

[Jack-Devel] alsa_out alternative for OSX

by Michał Badura

Hello, I have a Linux computer that is running a recording. I'd like to be able to also stream what is recorded to another computer through the network and listen to that with the speakers. I'm using Jack 1. I'm running jackd -d net on the slave computer, and jack_netsource on the recording one. Then, to play the sound through the speakers, I run alsa_out on the slave computer and connect the appropriate ports. Now I'd like to be also able to listen on a computer with OSX (the recording computer stays the same). I've installed jack from Macports, but there is no Alsa for OSX. What can I do to get the same result? Thank you, Michal Badura

8 years, 5 months

[Jack-Devel] Fwd: MIDI in Jack

by George Martínez

---------- Forwarded message ---------- From: "George Martínez" <latenciaalcontacto789(a)gmail.com> Date: Jul 9, 2016 3:49 PM Subject: MIDI in Jack To: <jack-devel(a)jackaudio.org> Cc: Hi :) I will love to know how to use the Jack application with MIDI Do I have to download virtual midi cables for that? Does it provides low latency MIDI? Thank you and great app by the way

8 years, 5 months

[Jack-Devel] A way to get notified when the current timebase master resigns?

by micu

Hey guys, Currently I am hacking in Jack transport support for a certain project. And while doing that, I am wondering whether it is possible to get a notficiation when the current timebase master has stepped down. Bascially what I have in mind for my client: * During startup, check if there is a timebase master and if not, be it (which I know is possible with jack_set_timebase_callback(..,1,...)). * In case there was another timebase master that resigns at a certain point in time (leaves the graph, steps down for some reason,...), take over the timebase. I couldn't figure out a way to get a notification (callback etc.) that the current timebase master just has stepped down. Is there one? If not, is there a specific reason for that? Your help would be highly appreciated. Kind regards, micu -- OpenPGP / GnuPG: 0xE4CB4E80 Fingerprint: 1A15 A480 1F8B 07F6 9D12 3426 CEFE 7455 E4CB 4E80 <<</>> http://www.micuintus.de

8 years, 5 months

Re: [Jack-Devel] graph simplification using mathematics?

by Thomas Brand

On Sat, July 2, 2016 23:14, StÃ©phane Letz wrote: > Faust : http://faust.grame.fr > Faust was the first thing that came to mind indeed! The introduction paragraphs in the documentation says -specification language -describe signal processors from a mathematical point of view -free from implementation details But right after that: -FAUST programs are fully compiled, not interpreted. I can imagine to bundle FAUST code from different processors semi-automatically or handcrafted to one unit relatively easily. However i was thinking in a direction where the units live in a host still as single units, to be connected in different ways, and the host would dynamically derive a single math operation of the current graph. I understand this would include recompilation or some kind of JIT compilation in order to work. If possible at all, i think Faust would currently be the best fit, since it already offers some of the fundamental concepts needed to even think about doing something like this. That would allow large graphs with almost no context switches (this is pure speculation). Greetings Tom PS: jack-devel list added to reply > >> Le 2 juil. 2016 Ã 22:58, Thomas Brand <tom(a)trellis.ch> a Ã©crit : >> >> Hi, >> i wondered if the following scenario could work. Assuming DSP is >> basically maths, and the formula and variables for every plugin would be >> known, would it then be possible to magically simplify all formulas of >> all plugins to one single formula doing all in one step? Does this sound >> weird? Greetings >> Tom >>

8 years, 5 months

[Jack-Devel] Compiling jack2 in mixed mode

by DjZU

Hi there, I've been happily using the pre-installed Jack2 that comes with Ubuntu Studio 14.04.3. Now I require the ability to use more than 64 clients then tried to compile Jack2 from the package JACK 1.9.10 found at jackaudio.org/downloads I'm running on a 64 bits machine but would like to get support for 32 bits applications as well. Configure runs fine with ./waf configure --prefix=/usr --dbus --profile --mixed --clients=256 --ports-per-application=2048 --alsa --libdir=/usr/lib/x86_64-linux-gnu/ --libdir32=/usr/lib/i386-linux-gnu/ Then build fails: (...) /usr/bin/ld: cannot find -ldbus-1 (...) I know it has something to do with the 32 bits library of dbus but need help to find out how to get them properly. I have already the following installed: sudo apt-get install build-essential gcc-multilib g++-multilib fakeroot checkinstall sudo apt-get build-dep jackd2 sudo apt-get install libdbus-1-3:i386 Am I still missing some libraries? Is it about some environment variable? Is it necessary to compile libdbus? Thanks for your input. DjZU

8 years, 5 months

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JackAudio July 2016