Linux-audio-dev

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7501 discussions

Re: [linux-audio-dev] Re: How to use the alsa sequencer?

by Pedro Lopez-Cabanillas

On Sunday, 18 June 2006, Stephen Cameron wrote: > > Hi, > > > > I'm trying to figure out how to use the ALSA sequencer > > with my app. (to date, I've been just using raw midi). [..] > But if I take out this line > > snd_seq_ev_set_dest(&ev, 128, 0); > > And replace it with: > > snd_seq_ev_set_dest(&ev, SND_SEQ_EVENT_PORT_SUBSCRIBED, 0); > > And try to use aconnect to connect things together, it doesn't > seem to work. > > So, there's some piece of the puzzle regarding how aconnect > works that I'm missing. snd_seq_ev_set_subs(&ev); I guess you may want to generate the ALSA library documentation from the sources with doxygen. It is also available online: http://www.alsa-project.org/alsa-doc/alsa-lib/seq.html Regards, Pedro

19 years

[linux-audio-dev] Re: Writing a winner takes it all gain filter.

by Bill Schottstaedt

Why do you say sndlib is "poorly maintained"? I did not get any bug reports that I remember. Also, it can be used with LADSPA, but I prefer a higher level approach.

19 years

[linux-audio-dev] Writing a winner takes it all gain filter.

by Alex Polite

Hi there. Thanks to everyone who responded to the request about high level languages for audio work. I made a wikipage to order your input and my findings. http://tinyurl.com/p4zqo It definitely looks like Faust is the most serious contender for writing LADSPA plugins. It seems to be actively maintained and well documented. It claims to be able to generate different types of plugins/applications from the same code. I'll print the tutorial and read it over the weekend. My first project will be a winner-takes-it-all-gain filter that takes n number of inputs and lowers the gain on all but the loudest signal. I want to use this on recordings of conversations where each speaker has a separate microphone. First I tried sidechain ducking which didn't really work for me. Then I tried expanding each channel, so as to mute it when it fell under the threshold. That works pretty well but it's not perfect. This winner-takes-it-all thingy should be dead simple to implement and I expect it work pretty well. alex -- Alex Polite http://flosspick.org - finding the right open source

19 years

Re: [linux-audio-dev] Writing a winner takes it all gain filter.

by Kjetil S. Matheussen

"Alex Polite": >Hi there. > >Thanks to everyone who responded to the request about high level >languages for audio work. >I made a wikipage to order your input and my findings. > >http://tinyurl.com/p4zqo > >It definitely looks like Faust is the most serious contender for >writing LADSPA plugins. It seems to be actively maintained and well >documented. It claims to be able to generate different types of >plugins/applications from the same code. I'll print the tutorial and >read it over the weekend. > I suggest that you rewrite the comment about snd. Writing "lispish, yuck" doesn't give you much credit as someone worth listening to. Also, for many other really good alternatives, like csound and supercollider, you have just written "naa". I suggest that you do some more research as well...

19 years

Re: [linux-audio-dev] Writing a winner takes it all gain filter.

by Kjetil S. Matheussen

Steve Harris: >Hum. It's maybe not tactfuly expressed, but the s-expression syntax has a >number of objectors with informed positions. > >It is near one end of a broad spectrum of languages so inevitably not to >everyones taste. Sure. Syntax can be more compact without s-expressions, and the syntax can also be more formed towards specific purposes without s-expressions as well, like smalltalk that use {...} instead of (lambda ()...), and C that use {...} instead of (begin ...), and things like accessing array values or setting values requires more characters with s-expression since you can't use special characters for common tasks. But the fact that you have complete control over the language in a way that a non-lisper is probably not able to understand without ever using lisp macros weights up for all those things. However, when people normally bash lisp, its probably because of the following reason: All the paranthesis looks ugly and are confusing. For example, I actually spent almost two years programming lisp before I started to like lisp very much. The paranthesis confusion dissapeared quickly, but thinking lispish was harder. Before that, I thought python was the most beautiful language of them all. (I knew about 20 programming languages at that time.)

19 years

[linux-audio-dev] [iua-mtg] CLAM 0.91.0

by Pau Arumi

CLAM 0.91.0 Release Announcement ´Spectral transformations, annotator, packaging, and desktop integration release' We are glad to announce the 0.91.0 CLAM release which comes by the hand with Music Annotator 0.3.2, Network Editor 0.3.1 and SMSTools 0.4.1. They are available for download as source tarballs and also as binary packages for Windows, Ubuntu dapper, Debian sid and Fedora Core 5. MacOsX binaries are not available for this release, but we promise they will be back soon. This release is the first official one which incorporates the new CLAM Music Annotator featuring chord extraction. Almost 30 new spectral transformations have been incorporated into the processing repository. Some of them are already available from the NetworkEditor. Application usage has received some extra stress on this release. Applications are better integrated on Windows and Linux desktops. Step by step application tutorials are available on the clam wiki for Music Annotator [1], SMSTools [2], Network Editor and Prototyper [3]. And, all of them all provide examples to start with. Please read these and other improvements in the changelog [4] or visit our website [5] for further details. We expect as much feedback as possible from all our users. Besides the mailing list, you can likely find us at #clam channel on FreeNode (IRC network). The CLAM team [1] http://iua-share.upf.es/wikis/clam/index.php/Music_Annotator_tutorial [2] http://iua-share.upf.es/wikis/clam/index.php/SMSTools_tutorial [3] http://iua-share.upf.es/wikis/clam/index.php/Network_Editor_tutorial [4] http://clam.iua.upf.edu/ChangeLog.html [5] http://clam.iua.upf.edu

19 years

[linux-audio-dev] Re: Writing LADSPA plugins in high level language?

by Kjetil S. Matheussen

Phil Frost: > Subject: Re: [linux-audio-dev] Writing LADSPA plugins in high level > language? > To: The Linux Audio Developers' Mailing List > <linux-audio-dev(a)music.columbia.edu> > Message-ID: <20060614132522.GA3483(a)unununium.org> > Content-Type: text/plain; charset=us-ascii > > On Wed, Jun 14, 2006 at 07:47:36AM +0200, Alex Polite wrote: >> Hi there. >> >> Is it possible to write LADSPA plugins in anything but C/C++? I prefer >> perl, ruby or python. >> >> alex > > Anything but C/C++, yes. See FAUST [1], a compiled language designed > specificly for processing audio streams. Perl, Ruby, or Python, not > really. > > [1] <http://faudiostream.sourceforge.net/> The realtime extension for snd (scheme-like language) is another: http://www.notam02.no/arkiv/doc/snd-rt/ Here is a cool alsa softsynth written in that system: http://ccrma.stanford.edu/~kjetil/220c/

19 years

[linux-audio-dev] gettimeofday() freeze?

by Steve

Hi, Tonight I actually for once got around to working a bit on my pet audio project, and thought I'd finally try to tackle my issues with a processor-intensive audio loop. So I started writing a simple timing class (C++) to do some profiling... Unfortunately, instead I've found myself wasting my time because my computer (or at least X) keeps freezing! It seems that whenever I put a call to gettimeofday() in my audio loop (which gets called about every 40-or-so milliseconds, a latency I'd like to reduce), and run the program, everything just freezes... no mouse, keyboard, no screen updates, etc. Reboot required. (I tried using ssh from another computer but got no response... strangely I did get a ping response however.) To be more specific, the loop is actually a callback from PortAudio. With gettimeofday commented out, there is no freeze, the software runs as expected. Originally I thought it might be a priority problem, but I tried running it without a priority boost and using "nice -n 19", but still I get a system freeze. It's strange, because I was under the impression that a user process should never be able to hang my whole system if not running as root. Has anyone else had issues with this? Is there a better way to profile my code? Unfortunately it's a GUI program (using SDL for graphics) so it's difficult to run it in text mode. I might try figuring out how to comment out all the graphics stuff though, to see if it has the same effect without X running. I'm using Ubuntu Dapper, up-to-date: $ uname -a Linux hal9000 2.6.15-22-686 #1 SMP PREEMPT Sun May 7 16:37:57 UTC 2006 i686 GNU/Linux Thanks, Steve

19 years

Re: [linux-audio-dev] Writing LADSPA plugins in high level language

by Kjetil S. Matheussen

Albert Graef: > assembler for the low-level stuff. (Not sure about snd, does it compile > to native code which can execute in realtime?) Yes, the realtime extension that I wrote compiles a scheme-like language into hard realtime-safe c code, which can be run and scheduled while snd is running. Its not optimizing as much as faust, but mostly its not significantly slower than hand-written C either. Sometimes it can even be faster. Its a practical language to get real things done because it blends into guile scheme and common lisp music so that everything is in the same source and communicates with each other. Its possible to implement things like ardour or supercollider in snd if anyone want to do that (although they have to fix some of the many bugs first :-) ).

19 years

[linux-audio-dev] Re: Writing LADSPA plugins in high level language?

by Kjetil S. Matheussen

"David Cournapeau": >>> >>> On Wed, Jun 14, 2006 at 07:47:36AM +0200, Alex Polite wrote: >>>> Hi there. >>>> >>>> Is it possible to write LADSPA plugins in anything but C/C++? I prefer >>>> perl, ruby or python. >>>> >>>> alex >>> >>> Anything but C/C++, yes. See FAUST [1], a compiled language designed >>> specificly for processing audio streams. Perl, Ruby, or Python, not >>> really. >>> >>> [1] <http://faudiostream.sourceforge.net/> >> >> >> The realtime extension for snd (scheme-like language) is another: >> http://www.notam02.no/arkiv/doc/snd-rt/ >> >> Here is a cool alsa softsynth written in that system: >> http://ccrma.stanford.edu/~kjetil/220c/ > there is also chuck, that nobody has mentionned, I think : > > http://soundlab.cs.princeton.edu/research/chuck/ > Not really. Chuck code runs in a VM and does not compile to native machine code. It also process blocks of samples, while faust and snd process one and one sample. In this respect, Chuck is more in the same class of programs like Supercollider, nyquist, csound, pd and many many others.

19 years

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