Linux-audio-dev

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7515 discussions

[linux-audio-dev] Real time delay tutorials?

by Iain Duncan

Anyone have a good suggestion for a tutorial for making accurate high-resolution high-priority clocks in C? I found some tutorials but they were kinda old, so wondered if they might be out of date as to how far real-time scheduling has come on linux. I want to be able to wake up a pthread very accurately. Thanks Iain

20 years

[linux-audio-dev] Setting the Beat of a Clock

by CapnLinux

I would like to build an application to assist in setting the "Beat" of a pendulum type clock. This is a tool used by a clock repair person to set a clock to keep accurate time. It is basically a low frequency oscilloscope with some specialized functionality. A microphone is placed inside the clock case and attached to the mic input of the sound card. I want to have a display of the resulting tick and tock waveforms. There are two primary functions that are needed to accurately set a clock's beat. One is to be able to compare the tick waveform to the tock waveform. A clock that is off balance and hence off beat will have a difference in the sound of the tick and the tock. Tick being the pendulum swinging in one direction vs the tock being the opposite direction swing. The other function is to measure the time between the tick and the next tick or full cycle of the pendulum swing. For instance, a lot of pendulum clocks are set to have a pendulum cycle time of exactly one second. Measuring this to say, hundredths of a second allows for accurate adjustment of the clock. I am looking for pointers to libraries and sample code that might help me get started with this project. Once completed, it would be released as an Open-Source project for use by any clock repairer that wants it. I have not seen any open-source projects of this type and the commercial units that perform this function cost several hundred dollars.

20 years

[linux-audio-dev] (1) Jack -- busted? (2) jack.udp -- busted? (3) jack-osx -- binary-only?

by Stephen Travis Pope

Helo all, (1) I'm new to jack (but a competent programmer). It appears that the cvs repository is missing the top-level configuration file. Following the instructions from the download page, I do a clean cvs checkout on a Linux machine, cd to the jack directory, and execute ./autogen.sh This fails saying /usr/bin/m4: configure.in: No such file or directory configure.ac: 218: required file `config/ltmain.sh' not found Am I missing something? (2) My actual interest is in looking into the jack-udp protocol, and I tried getting this all to work on a Mac a few days ago and actually got much further, but it looks like file recv.c has problems since it doesn't appear to include any definition if the jackudp_t data type that it tries to declare in the first line of code; i.e., I get, /Users/stp/Code/jack/jack.udp/recv.c:14: error: 'jackudp_t' undeclared (first use in this function) Does jack.udp work in general? Is there any documentation of the actual protocol used? Has anyone thought of using TCP instead of UDP? (3) I know that there's a binary distribution of the Mac OSX release, and have it installed; does anyone know where there's a source distribution? stp ...any assistance greatly appreciated... -- Stephen Travis Pope -- http://create.ucsb.edu/~stp Center for Research in Electronic Art Technology, University of California, Santa Barbara Really—I don't know what the meaning or purpose of life is. But it looks exactly as if something were meant by it. — C. G. Jung

20 years

Re: [linux-audio-dev] Re: [Jackit-devel] (1) Jack -- busted? (2) jack.udp -- busted? (3) jack-osx -- binary-only?

by Robert Jonsson

Hi, On Sunday 25 Sep 2005 05:43, Stephen Travis Pope wrote: > Netjack sounds interesting, but the SourceForge site has no code and > no forum postings. > Perhaps this is a case of starting a project by claiming the spot on > SourceForge... The code is there, but it's only in cvs, there are unfortunately no releases made on that site yet (says a little about the lack of maturity). As for the technical merits I see that the discussion has been more about the transport mechanism and this project hasn't really touched on that subject yet. To keep it simple the data is sent via udp with floats directly. For lowlatency, CPU-hungry, work the interesting bit is that there is a master jack-server that drive all slave jack-servers, thus working around the sync issues. A drawback of this is that its only (easily) allowed to connect an actual soundcard to the master jack-server, the others are best suited for various processing tasks (Outboard effects, softsynths). Regards, Robert > > stp > > -- > Stephen Travis Pope -- http://create.ucsb.edu/~stp > Center for Research in Electronic Art Technology, University of > California, Santa Barbara > Really—I don't know what the meaning or purpose of life is. > But it looks exactly as if something were meant by it. — C. > G. Jung > > Begin forwarded message: > > From: Robert Jonsson <rj(a)spamatica.se> > > Date: September 23, 2005 1:23:28 PM PDT > > To: linux-audio-dev(a)music.columbia.edu > > Cc: Stephen Travis Pope <stp(a)create.ucsb.edu>, jackit- > > devel(a)lists.sourceforge.net > > Subject: Re: [linux-audio-dev] Re: [Jackit-devel] (1) Jack -- > > busted? (2) jack.udp -- busted? (3) jack-osx -- binary-only? > > > > > > Hi, > > > > On Friday 23 Sep 2005 21:35, Eric Dantan Rzewnicki wrote: > >> On Fri, Sep 23, 2005 at 12:10:15PM -0700, Stephen Travis Pope wrote: > >>> (2) My actual interest is in looking into the jack-udp protocol, and > >>> I tried getting this all to work on a Mac a few days ago and > >>> actually > >>> got much further, but it looks like file recv.c has problems > >>> since it > >>> doesn't appear to include any definition if the jackudp_t data type > >>> that it tries to declare in the first line of code; i.e., I get, > >>> > >>> /Users/stp/Code/jack/jack.udp/recv.c:14: error: 'jackudp_t' > >>> undeclared (first use in this function) > >>> > >>> Does jack.udp work in general? > >>> Is there any documentation of the actual protocol used? > >>> Has anyone thought of using TCP instead of UDP? > >> > >> Alban Peignier uses Rivendell with jack for radio broadcasts. As I > >> understand it he uses jack.udp to send the audio from the > >> broadcast box > >> to a separate box that does encoding for web streaming. So, there > >> is at > >> least one working use case. > > > > Distributing jack interests me, but sadly I have no time to dive > > deeper at the > > moment. > > Jackudp had a sibling called udpsync (not sure about the source > > heritage) > > which, instead of connecting two jacks through the client-interface > > (which is > > prone to sync problems) drives the "slave" through the backend. It > > does > > work, but is by no means finished. > > Don't know if it's of interest, the latest sources are here anyway: > > http://sourceforge.net/projects/netjack > > > > > > Regards, > > Robert > > > > -- > > http://spamatica.se/musicsite/ -- http://spamatica.se/musicsite/

20 years

[linux-audio-dev] libcui - design-question

by Julien Claassen

Hi all! I'm trying to design a library, which should provide "graphical objects" for the console. Meaning standardised buttons, checkboxes, sliders, etc. The purpose of this project is: to bring gui-based audio-software to the console. What I'm wondering now is the following: It would still be a certain amount of work, to program a textbased ui with this library. So which way of using this library would be best? Could any of you imagine good ways to communicate objects of your software to a kind of server. Something like OSC? So this server can run and you start the program on the gui and it tells the server: I have th following objects. Could this be a way of designing it? Would this be sensible? Or would it be better to only provide a c++ API? Good thoughts and ideas are wellcome. Kindest regards Julien -------- Music was my first love and it will be my last (John Miles) ======== FIND MY WEB-PROJECT AT: ======== http://ltsb.sourceforge.net - the Linux TextBased Studio guide

20 years

[linux-audio-dev] Re: (1) Jack -- busted? (2) jack.udp -- busted? (3) jack-osx -- binary-only?

by lazzaro

On Sep 24, 2005, at 9:02 AM, linux-audio-dev- request(a)music.columbia.edu wrote: > Is anyone interested in collaborating on a common sample streaming > protocol (possibly based on a somewhat simplified version of SDIF or > the SC3 protocol)? I'd recommend using RTP as your base protocol, and defining your SPIF or SC3-like payload as an RTP payload format. You'll pick up the entire IETF multimedia protocols for free this way, including RTP MIDI: http://www.cs.berkeley.edu/~lazzaro/rtpmidi/index.html I think when it comes to networking, the writing is on the wall when in comes to packet loss being a part of the environment you need to live in. Most new purchases of computers are for laptop computers, most of those users want to use WiFi as their network, and the Internet layer sees 1-2% packet loss on WiFi. Also, we live in an era where people want to run LAN apps on the WAN and WAN apps on the LAN, and packet loss is also an unavoidable part of the WAN Internet experience. Finally, modern applications want to use link-local Internet multicast. RTP was built for letting payload formats handle packet losses in a way that makes sense for the media type -- RTP MIDI is an extreme example of this, but the audio and video payload formats are loss tolerant in more subtle ways. RTP is also multi-cast compatible. Finally, with RTP there's a standardized way to use RTSP and SIP for your session management if you wish, or if you prefer, you can just build RTP into whatever session manager you have committed to (like jack). --- John Lazzaro http://www.cs.berkeley.edu/~lazzaro lazzaro [at] cs [dot] berkeley [dot] edu ---

20 years

[linux-audio-dev] [ANN] ALSA MIDI Kommander

by Pedro Lopez-Cabanillas

ALSA MIDI Kommander is a DCOP [1] interface exposing many ALSA Sequencer [2] features for shell scripts, Kommander scripts [3], or KDE programs requiring MIDI Sequencer services. A few MIDI utilities have been developed with this tool, which can be used both as programming examples and as real work tools. The main program, "kaseq" is a single executable, used as a DCOP service program. It runs as a daemon, allowing only a single running instance, and providing a system tray icon to give visual feedback for MIDI activity, and a way to control the program execution itself. It depends on KDE 3.x and the Qt library. More information at this provisional project site: http://kmetronome.sourceforge.net/kaseq/ Downloads http://sourceforge.net/project/showfiles.php?group_id=134956&package_id=164… Source packages http://prdownloads.sourceforge.net/kmetronome/kaseq-0.2.3.tar.bz2?download http://prdownloads.sourceforge.net/kmetronome/kaseq-0.2.3.tar.gz?download Copyright (C) 2005, Pedro Lopez-Cabanillas <plcl AT users.sourceforge.net> Released under the terms of the GNU General Public License (GPL) References [1] DCOP http://developer.kde.org/documentation/other/dcop.html [2] ALSA Sequencer API http://www.alsa-project.org/alsa-doc/alsa-lib/seq.html [3] Kommander http://kommander.kdewebdev.org/

20 years

Re: [linux-audio-dev] libcui - design-question

by Kjetil Svalastog Matheussen

Paul Davis >On Tue, 2005-09-20 at 08:29 +0300, Aaron wrote: >> please save me from another lisp/scheme scriptable application.... >> > The scripting should be in a language easy enough for a non programer to >> use. >> >> Is xsl a possibility or is there a scripting language that is easier >> than lisp/scheme? > >breathe deeply. think of snakes. say "python". Are you serious? Do you know python? I hope not... I don`t want to start a flame-war over programming languages, but I know both scheme and python very well, and would never consider python as an extension language again. --

20 years

[linux-audio-dev] [ANN] Slat 0.3

by james＠dis-dot-dat.net

Slat 0.3 is now finished. Windows size can be set with -s Notes are linearly spaced (to prevent the headf**k) Flat/sharp notes are darkened http://blog.dis-dot-dat.net/2005/09/slat-03.html -- "I'd crawl over an acre of 'Visual This++' and 'Integrated Development That' to get to gcc, Emacs, and gdb. Thank you." (By Vance Petree, Virginia Power)

20 years

[linux-audio-dev] USB-MIDI Transfer rate

by Jens M Andreasen

Hi! I am currently working on digesting the USB-MIDI Class Definition ... http://www.usb.org/developers/devclass_docs/midi10.pdf As I understand, you can have up to 16 USB MidiStreams (MS), each equal to a physical midi-cable (and each "cable" having 16 virtual midi-channels.) There is a bandwith limit of one 3-byte midievent/ms which makes sense given the bandwith of of a physical midi-cable The MIDI-USB device also have a control channel without any endpoints (without any physical midi-jacks.) Again only as far as I have understood; the control channel is not a MidiStream and should therefore be able to accept a significantly higher transfer rate than the physical MidiStreams. Question: How do I determine the max transfer rate for the control channel (bInterFaceSubClass == 1) as apposed to the physical midi-outs (bInterFaceSubClass == 3) ?+ This is for setting LEDs partially lid for more than one parameter, by pulsewidth-modulation over USB-MIDI. mvh // Jens M Andreasen

20 years, 1 month

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Linux-audio-dev