JackAudio

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602 discussions

[Jack-Devel] running jackd from rc.local

by Athanasios Silis

Hi all, I am trying to run jackd instance from /etc/rc.local (along with a few other applications) from a custom made init script. The system is ubuntustudio and I have setup everything to have elevated permissions when executing applications from the @audio group. so when I am logged on, I see this: nass@starkill:~$ ulimit -r -l real-time priority (-r) 95 max locked memory (kbytes, -l) unlimited which is expected and I can execute the script I wrote. but, when I execute my script from /etc/rc.local as su - nass -c "ulimits -r -l cd audio_setup/scripts ; bash ./start_audio" then my user does not (yet?) have elevated permissions. real-time priority (-r) 0 max locked memory (kbytes, -l) 64 is there a script I can run before my start_audio script to elevate my permissions? thank you

10 years, 9 months

[Jack-Devel] Jack on Raspberry PI 2

by Ron

Hello, Sorry about that. My mistake. -- Due to administrative overhead, messages sent by non-members to jack-devel will be discarded. Please join the mailing list and then resend your message. Jack on Raspberry PI 2.eml Subject: Jack on Raspberry PI 2 From: Ron <rlpatton(a)aol.com> Date: 4/16/2015 10:47 To: jack-devel(a)lists.jackaudio.org Hello, I have downloaded, built and installed the latest version of Jack on a Raspberry PI 2 running Raspbian (Linux 3.18.11-v7+ #777 SMP PREEMPT). ron@squireoaksfarm-radio ~/src/quick2wire-python-api $ jackd --version jackdmp 1.9.11 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2014 Grame. jackdmp comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details jackdmp version 1.9.11 tmpdir /dev/shm protocol 8 I have been all over the internet trying to find a solution to the following error that prevents the jack server from starting (using qjackctl): 10:31:31.869 Patchbay deactivated. 10:31:31.882 Statistics reset. 10:31:31.931 ALSA connection change. Cannot connect to server socket err = No such file or directory Cannot connect to server request channel jack server is not running or cannot be started 10:31:31.961 ALSA connection graph change. 10:31:35.651 JACK is starting... 10:31:35.653 /usr/local/bin/jackd -dalsa -dhw:0 -r48000 -p1024 -n2 Cannot connect to server socket err = No such file or directory Cannot connect to server request channel jack server is not running or cannot be started 10:31:35.682 JACK was started with PID=9484. jackdmp 1.9.11 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2014 Grame. jackdmp comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details JACK server starting in realtime mode with priority 10 Cannot lock down 82278944 byte memory area (Cannot allocate memory) 10:31:36.022 JACK was stopped successfully. 10:31:36.028 JACK has crashed. 10:31:37.778 Could not connect to JACK server as client. - Overall operation failed. - Unable to connect to serve r. Please check the messages window for more info. Cannot connect to server socket err = No such file or directory Cannot connect to server request channel jack server is not running or cannot be started I have tried to start the sever with the "--no-mlock" option. Here are the contents of audio.conf ron@squireoaksfarm-radio /etc/security/limits.d $ more audio.conf # Provided by the jackd package. # # Changes to this file will be preserved. # # If you want to enable/disable realtime permissions, run # # dpkg-reconfigure -p high jackd @audio - rtprio 95 @audio - memlock unlimited #@audio - nice -19 The user "ron" is a member of the audio group. Please help, Ron 73 Ron / W4MMP

10 years, 9 months

[Jack-Devel] Message to Fons (which mail seems to be currently broken ?)

by Stéphane Letz

Hi Fons, After our discussion in LAC I did two things : - remove some log messages - allow to better control thread priority definition, basically following the model used on Linux (server_priority = N, client_priority = N-5 so that the client may use threads with a priority between client RT value and server RT value) (see : http://comments.gmane.org/gmane.comp.audio.jackit/17931). On Windows it works like the following: - using the -P number below 89 make all RT thread takes THREAD_PRIORITY_TIME_CRITICAL priority - using value more than 89 moves in the MMCSS ("Pro Audio") class where 4 values can be used (AVRT_PRIORITY_LOW, AVRT_PRIORITY_NORMAL, AVRT_PRIORITY_HIGH, AVRT_PRIORITY_CRITICAL) - client priority is 3 below server priority: so if 92 is used for the server, then JACK server RT thread will actually takes AVRT_PRIORITY_CRITICAL and client thread will use AVRT_PRIORITY_CRITICAL - 3 = AVRT_PRIORITY_LOW - then the client my possibly use a value between AVRT_PRIORITY_LOW and AVRT_PRIORITY_CRITICAL for some other threads. Tell me it if works the way you need to, and if not, how we can improve the implementation. Links for the binaries here: https://dl.dropboxusercontent.com/u/28869550/Jack_v1.9.11_32_setup.exe https://dl.dropboxusercontent.com/u/28869550/Jack_v1.9.11_64_setup.exe Thanks. Stéphane

10 years, 9 months

Re: [Jack-Devel] Avoiding spinlocks in a parallel sequencer

by Johannes Lorenz

> Do you want to synchronize JACK clients so they do something in the same > cycle / at the same sample time? Yes, I think so. > You could inject an event to JACK that's being distributed to the clients > (inside JACK). The clients would then receive the events in the same cycle > and can process (at given sample pos) in that cycle. This sounds very good. However, I am not sure what you mean in terms of code. Can you please provide some example code?

10 years, 9 months

Re: [Jack-Devel] Avoiding spinlocks in a parallel sequencer

by Johannes Lorenz

> > Nonetheless, if I have 40 instances of zyn, I'd > > like to (actually must) compute them concurrently. So how to do this with > > one client? > > By using your own internal graph mechanism that has parallel capabilities. > See, for excample, https://github.com/flowprogramming/dspatch This one is based on pthread_cond_wait(), which is either implemented as a spinlock or not realtime safe (I guess the second). So how can this help? > > The best way I can see is using an array of jack clients, and hoping > > they'll process() at the same time. However, this sounds very tricky... > > There can be very good reasons for using JACK 1. If a user is doing that, > you won't get any parallelization at all. Does JACK 2 allow to use multiple jack clients that call process() at the same time? Or does it allow to enter process() with multiple threads? There seems to be no documentation/tutorial about JACK 2.

10 years, 9 months

Re: [Jack-Devel] Avoiding spinlocks in a parallel sequencer

by Johannes Lorenz

> But again, I wasn't proposing "one jack client per effect" ... I was > proposing only a single JACK client per application, and NOT using JACK's > audio graph capabilities within your application: you would need to compute > execution order yourself or use a nice library for this (not that there > necessarily are any nice libraries). Need to ask once more. Assuming I'll do this - one jack client and zynaddsubfx as a plugin. Nonetheless, if I have 40 instances of zyn, I'd like to (actually must) compute them concurrently. So how to do this with one client? The best way I can see is using an array of jack clients, and hoping they'll process() at the same time. However, this sounds very tricky...

10 years, 9 months

Re: [Jack-Devel] Avoiding spinlocks in a parallel sequencer

by Johannes Lorenz

> But again, I wasn't proposing "one jack client per effect" ... I was > proposing only a single JACK client per application, and NOT using JACK's > audio graph capabilities within your application: you would need to compute > execution order yourself or use a nice library for this (not that there > necessarily are any nice libraries). Ok, so you do not propose to use multiple clients and exploit JACK's graph capabilities. Just for interest: For what (main) reason(s) didn't you propose it? Thanks everyone for the help.

10 years, 9 months

Re: [Jack-Devel] Avoiding spinlocks in a parallel sequencer

by Johannes Lorenz

Am Donnerstag, 9. April 2015, 09:00:38 schrieben Sie: > Speaking entirely personally, I think this design is just plain nuts. I > know there are some JACK-ecosystem developers who disagree with me, but I > think that using JACK clients for this purpose is just wrong and is pushing > the design scope for JACK. Ok, let's say I'll do what multiple people proposed here: one jack client per effect + only data exchange between effects via jack ports. Then see this example: piano roll ----- (notes) -----> synthesizer How should one transfer notes using a jack buffer? Of course, one could make a structure to transfer notes, cast this structure to const char*, and *hope* it fits into the port buffer. Is there any better way? Maybe a "custom port type"?

10 years, 9 months

Re: [Jack-Devel] Avoiding spinlocks in a parallel sequencer

by Johannes Lorenz

Hi, > So a part of the dependencies in the signal processing flow is only > known to your sequencer, which leads to a situation where jack can not > know, if all dependencies for running a certain client process function > are satisfied? > I personally would try to avoid that so that things will become easier, > which means no need for ringbuffers (input and output buffers that > depend on each other are passed together to the process function) and > spinlocks (jack always calls the clients callback, if data is definitely > available) for synchronization. This was my first thought aswell. However, if you'll end up with 40 lfo generators that just compute f(x)=sin(x) (or even simpler), you'll have 40 additional threads that need to communicate with each other. I wonder if that is so good...

10 years, 9 months

Re: [Jack-Devel] Avoiding spinlocks in a parallel sequencer

by Johannes Lorenz

Hi, > I try to understand your plan: > > simple data flow example: > > zynaddsubfx_1_output > > V > sequencer_client_1_input > > V > sequencer_input_ringbuffer > > V > (sequencer processing stuff) > > V > sequencer_output_ringbuffer > > V > sequencer_client_output > > V > system_client_input(hardware output) Your picture is indeed correct. To add some more examples: * Something like this is also possible sequencer_input_ringbuffer_1 sequencer_input_ringbuffer_2 V V plus (i.e. addition of sound-waves) V plus_effect_ringbuffer * The part that you labeled "(sequencer processing stuff)" might be filled with: V peak_controller_effect some lfo generator V (lfo) V (lfo) zynaddsubfx_2_volume_input zynaddsubfx_2_filter_freq_input V (zynaddsubfx_2) V zynaddsubfx_2_output V sequencer_client_2_input V > Maybe also what you envision to happen in which thread or which > callback? Let's take the second example. zynaddsubfx itself is in another process, so we don't need to run this at all. For feeding each ringbuffer from zyn, I planned to use a separate jack client. E.g., if process() of sequencer_client_1_input is being called, it simply copies "nframes" into sequencer_input_ringbuffer. Everything that now remains (e.g. lfo generator, peak_controller_effect, sending input to zynaddsubfx_2) is done by a process() callback of sequencer_client_output. I call this one the master jack client. About the problem: A point where I think spinlocks can't be avoided would be, e.g., reading from sequencer_output_ringbuffer. The sequencer's master jack client would need to do that in process(), but it can not guess when the ringbuffer reader from sequencer_client_2_input has even started to feed the ringbuffer. > Do you want to do some signal processing in your sequencer or would it > be ok to delegate this to other jack clients? (may be easier) Hopefully you got it from the explenations above: the master jack client would do this right now, as I planned. Other ideas will be fine, too. Though, I guess, for "some lfo generator", e.g., a separate jack client would be overkill, as this generator simply does, e.g., f(x) = sin(x).

10 years, 9 months

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