Linux-audio-dev

linux-audio-dev@lists.linuxaudio.org

7501 discussions

by Luis Garrido

Oh, well, since GUIs are this week's flavor in the list, I might as well throw FLAM's alpha in the mix. I am preparing FLAM's (Front-ends for Linux Audio Modules) first release. Among other things, FLAM intends to allow programmers and non-programmers alike to create their own (external) GUIs for audio plugins. At this moment only Rosegarden as a host and LADSPA as plugin type are supported, but this is hopefully just a first step. Project page: http://vagar.org/code/projects/flam Tutorial with a few screenshots: http://vagar.org/asciidoc/flam/primer/primer.html Source code repository: git clone http://vagar.org/git/flam I'd welcome any feedback, here or in the FLAM forums (registration required): http://vagar.org/code/projects/flam/boards Thanks! Luis

14 years, 4 months

do any of the jack client examples show playing a file from disk?

by drew Roberts

do any of the jack client examples show playing a file from disk? if so, which? if not, any links to simple code that does this? c++ or c? thanks in advance for any pointers. drew -- http://freemusicpush.blogspot.com/

14 years, 4 months

Dealing with time

by Joel Roth

Hi all, This meditation isn't about gray hair, sagging flesh or receding libido. :-) In debugging Nama's new audio editing functions, I'm noticing that I have more and more code dealing with time. I am concerned seeing a multiplicity of method names like adjusted_region_start_time or unadjusted_mark_time. I'm wondering if perhaps I can centralize or at least systematize this functionality. Nama deals with several kinds of time: Ecasound time. Positions in seconds or samples from the perspective of the Ecasound audio engine WAV time. Displacements in audio files. Track / Region time. Positions in a track or region Mark time. Nama currently has only one type of mark: marks anchored to an absolute project timeline. I think it also needs marks for positions in a tracks WAV files, which the user may trim or offset. Edit / offset-run time. This is what started the entire issue. To record a fix for a note at time T in a WAV file W, I use Ecasound's select object to offset all the WAV files in a project to start at time T. The fix, W', then gets placed at T using playat. MIDI time. There are plenty of references on this, and it's a subject of its own. Nama needs at least to know enough to work across the various systems for bridging between ALSA, JACK and MIDI. So do I need some Big Abstraction(tm), or shall I just continue to work incrementally? How do you think about time? I don't expect a simple answer or an answer at all, but it can help to formulate the question. Regards, Joel -- Joel Roth

14 years, 4 months

[ann] nova-simd

by Tim Blechmann

hi all, for some time, i have been working on nova-simd, a cross-platform SIMD library library written in c++. it abstracts the platform-specific APIs and provides a `vec' class, which maps to a SIMD floating-point vector on the target machines and which can be used to formulate more complex algorithms. for some commonly used vector functionality, helper functions are provided, which are built using the vec class. features: - same interface for different SIMD architectures - supported backends: sse-family, avx, altivec, arm/neon - some backends include vectorized implementations of libm functions - extensively used in supercollider - header-only c++ (no runtime dependencies, composable), no dependencies canveats: - little documentations/examples - no release, no tarball, just a git repository [1] and a web interface [2] - header-only c++ (no c support) maybe it is useful for other people as well... cheers, tim [1] git://tim.klingt.org/nova-simd.git [2] http://tim.klingt.org/git?p=nova-simd.git;a=summary -- tim(a)klingt.org http://tim.klingt.org Art is either a complaint or do something else John Cage quoting Jasper Johns

14 years, 4 months

Re: [LAD] Calculate R M S (Alfs Kurmis)

by Jeff McClintock

> From: Fons Adriaensen <fons(a)linuxaudio.org> > On Fri, Feb 18, 2011 at 07:36:44AM +1300, Jeff McClintock wrote: > > > With a RMS VU Meter you measure a 1KHz tone as a reference. > > A contradiction... A VU does not measure RMS, whatever does measure > RMS is not a VU. Isn't a VU Meter a standard root-mean-square function followed by a 300ms integration to give it some 'weight'? ...calibrated against a 1kHz tone?

14 years, 4 months

Calculate R M S

by Alfs Kurmis

Hi Experts. I wanna normalize my sound stream by loudness (energy / pressure / intensity) , not by peaks. How i do it ? Is available Jack plugin for so what ? What is (we hear as) "loudness" ? RMS or +(average) or something else ? Is somewhere available examples how to calculate RMS ? Is it done simlpe by :  int i, n;  double sums, rms;  sums=0.0;  n=10;  rms=0;  for(i=0; i<n;i++)  {   sums = sums + ( (double)i * (double)i );  }  rms = sqrt(sums / n);  printf("          rms = %12.12fnn", rms ); Is so sipmple algo good enough for frequencies > 10 kHz ? How to calculate RMS with hi-precision for frequencies > 10 kHz ? With inerpolation or so ? What is reference ( 0dB ) RMS for example for 16bit PCM signal 1024 samples ?   sqrt( 1024*(0x7FFF ^ 2) / 1024 )  ==  sqrt( (0x7FFF ^ 2)  ) == 0x7FFF  Is it simple  0x7FFF (32000 dec) ? How to calc RMS for stereo signal ? So , or somehow else ? for(i=0; i<n;i++)  {  ....    sums = sampleL/2 + sampleR/2;  } In case operating with float point, what should be a bit faster,  / 2  or * 0.5 ? How to gotta RMS value in dB ?    20 x log10(Measured/Reference0_dB)  or 10 x log10(Measured/Reference0_dB)  ?? Im just physics student and im new in DSP, so pleaz no angree about simple or stuppid questions. Any examples and hints welcomed. Many Tnx in advance. Alf ----

14 years, 4 months

Re: [LAD] Realtime threads and security

by Kjetil S. Matheussen

Paul Davis: > > On Thu, Feb 17, 2011 at 4:53 PM, Robin Gareus <robin(a)gareus.org> wrote: > >>> Aside of that, what about locks? I've many times been told that one mustn't do >>> anything that could block in a realtime thread. What are the consequences of >>> that? Could a malicious app freeze the system by blocking in a realtime thread? > > it poses no risks to anything except itself if it does that. blocking > in an RT thread matters to the thread, not to anything else. > > to demote RT threads that are doing too much you'd need a user-space > watchdog like das_watchdog > Actually, das_watchdog is not very useful anymore after the kernel developers implemented a scheme to avoid a process to take over the machine. This built-in scheme is also a watchdog, but much more fine graided than das_watchdog. And it is also (more often than not) useless, so one has to press the reboot button anyway. The sad thing is that this built-in watchdog in newer kernels fools das_watchdog into thinking that the system is operational. (@#$@#%%!#$$!!!) I should look into it though, it might not be impossible to tune das_watchdog to work again.

14 years, 4 months

Re: [LAD] Calculate R M S (Alfs Kurmis)

by Jeff McClintock

With a RMS VU Meter you measure a 1KHz tone as a reference. Best Regards, Jeff

14 years, 4 months

Devs needed for opensource virtual analog softsynth idea

by Sascha Schneider

Hi folks, inspired by a plan of a german onlinemag called amazona.de I came up with the idea that a virtual analogue opensource softsynth nativly running on Linux would be really nice. (a nice filterbank too, but thats another thing) Amazona planned a complete synth based on userpolls (only in german, sorry): http://www.amazona.de/index.php?page=26&file=2&article_id=3191 which is now realized as vst: (only german, too) http://www.amazona.de/index.php?page=26&file=2&article_id=3202 I know that Zynaddsubfx/yoshimi has a really strong soundengine and I asked myself, if it would be possible to take this engine or the DSSI-API and build a polyphonic softsynth with a nice UI like the new calf plugins or guitarix, a bit like the loomer aspect, with some discoDSP, a bit from the Tyrell or the Roland Gaia SH-01 with midilearn, ...... The problem I have are my programming skills, that are not good enough to code this kind of software by myself. Are there some LAD's willing to join/take/realise this idea?? If there is interest I could translate the ideas of amazona.de and we all could share our visions for a new kind of controllable virtual analogue softsynth. kind regards, saschas

14 years, 4 months

kokkinizita -- correction

by Fons Adriaensen

In a fit or complete braindeadness FA wrote: kokkinizita.linuxaudio.org 198.82.152.114 which should of course have been: 198.82.152.114 kokkinizita.linuxaudio.org Sorry for the confusion !!! -- FA

14 years, 4 months

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

Linux-audio-dev