Linux-audio-dev February 2004

linux-audio-dev@lists.linuxaudio.org

89 participants
88 discussions

Re: [linux-audio-dev] wcnt linear filters

by James W. Morris

>From: Tim Goetze <tim(a)quitte.de>J >Date: Tue, 3 Feb 2004 14:21:53 +0100 (CET) >resonant filters use recursion; the algorithm sometimes is coded as >'take this input sample and give me an output sample' for readability >but is easily adapted to arrays.W I think that maybe wcnt does both, all the modules process one sample at a time, and the filters add one sample to the array every time after processing x samples in filter array to get average for the one output sampleM >the maths behind them are intricate >(to me at least), D likewise; I had a look at harmony central (fairly helpful) which concreted realisation that I definately had not got any graspA of resonance in my filters. I looked in eq cookbook, there were bits and pieces which I had no more than vague notions of. >but you don't need too firm an understanding of the >theory to actually use Sthem. good! >you'll find code exampleHs for the >algorithm and the compuAtation of the recursion coefficients in almost >every major audio synthesis/processing package or at musicdsp.org . hmmm, I keep putting off loRoking at other peoples code, it's all greek to me. >steve's ladspa set has a very nice state-variable filter (svf) which >lends itself well for resonancTe and reasonably quick parameter >changes. you may want to try it first before resorting to coding your >own. I've not had much chance to uDse ladspa. I've compiled glame to use it's filter network, but there seems to be inputs and outputs Olacking, many are mono, I can't read a stereo file, through a reverb and out to another stereo Tfile, or from a stereo input on soundcard, through fx, to file, so I've given up on glame (again), plus I don't like how it wont delete the deleted things. Another one I keep trying is SND. I quite like it, but have only got the basics working, no effects etc. And I've got zero knowledge oNn scheme, guile whatever. I need to get motif again as I deleted it along with lesstif, and seemE to have lost cdrom....snd was not loading xm. no idea what this means: above fs/4 IIRC -- not too worried about it either. Well, I guess I'll try and learn from otheTrs code at long last, and nip on over to musicdsp.org. I remember last year I somehow had a strange notion there was not much more I could do to wcnt, and this year after a long break, everything's coming out of the woodwork, and there's all sorts needing lifts and tucks. James ~(sirromseventyfive)~ _________________________________________________________________ Tired of 56k? Get a FREE BT Broadband connection http://www.msn.co.uk/specials/btbroadband

20 years, 8 months

[linux-audio-dev] Software with source code?

by Juhana Sadeharju

Hello. I have partially lost the track on the latest audio and graphics development. Even I'm on 50+ mailing lists, the whole picture is blurry. So, I'm making a list of software which comes with source code. The list is intended more to developers who are looking for example codes, library codes, and projects to join. An unfinished list follows. The list format is simple: name and description. That is because one must be able to read the list through line-by-line without getting bored to details. Maybe later I will fill in the details: what re-usable gizmos the software have (filters, drawing algorithms, etc). Regards, Juhana Audio and graphics applications =============================== with source code for developers Audio ----- ac3filter AC3 decoder Alsa audio device drivers AlsaModularSynth (AMS) modular synth AlsaPlayer Anthem multitrack sequencer Aqsis Renderman renderer Ardour multitrack editor (and sequencer?) Audacity multitrack editor Audiality audiofile awesfx bacterium Brahms cdparanoia Cecilia graphical front end for Csound Csound modular synth Ecasound FluidSynth SoundFont synth gAlan modular synth gdam Glame gmorgan rhythm station, a pattern sequencer gmurf Gnomoradio a peer-to-peer music playing system Gramofile Horgand FM synth Hydrogen JACK JACK-Rack Jamin mastering tool Jazz jMax libsndfile mffmtimescale MusE multitrack audio and MIDI sequencer NoteEdit score editor OpenAL library for managing 3D spatialized audio devices OpenMusic PortAudio PureData (PD) Q/Q-Audio/Q-Midi Rezound Rosegarden multitrack audio and MIDI sequencer seq24 pattern sequencer solfege sooperlooper SoundFontCombi (SFC) MIDI router Specimen sampling synth SpiralLoop SpiralSynthModular (SSM) modular synth Supercollider Swami Sweep audio editor swh-plugins effect plugin collection tapiir TerminatorX TimeMachine timidity sampling synth with SoundFont support TSE3 sequencer engine (used by Anthem) ZynAddSubFX analog modelling synth CheeseTracker? LilyPond? Multitrack? Skale? SoundTracker? Ptolemy? Graphics -------- Ayam 3D modeller Aztec Blender CinePaint ClanLib 3D game library Coin 3D graphics library with Open Inventor API Crystal Space 3D game library dia Dore DRI Effectv ewave 3D modeller FOX toolkit for developing GUIs, with OpenGL widgets Freeman FreeType font rendering library GIMP Glade glaraocr Glide graphics library for 3Dfx Voodoo based cards gman gmone GNetLibrary GNUPlot scientific plotting gocr (jocr) Gozer text rendering library Imlib Impress imtools Innovation3D 3D modeller jpegsrc K3D 3D modeller kpovmodeler libart LibGLE OpenGL tubing and extrusion library LibGNetwork libgnomecanvas libpng LibSolid Mesa MeshIO library for loading 3D model files, 3DS format Nebuladevice MindsEye Moonlight Mops (ayam?) Ogre OpenEXR Open Inventor 3D graphics library OpenRM Open Scene Graph OpenSG Pango text rendering library Panorama Pixelize pixelizes an image using other images as pixels Pixie PLIB PLplot scientific plotting POV-Ray Prettypoly qcad Radiance Renderpark Rise SDL SGL SIPP polygon renderer Sketch smpeg Sodipodi SuperZoom tgif Threedom (3dom?) 3D modeller tiff UGS3D Vertex 3D modeller Vreng networked virtual 3D world engine VR Juggler VTK 3D visualization library, OpenGL based xcircuit circuit schematics drawing program xfig XFree86 Xine video player Xite xpdf XSane Matterial? Khoros? gSculpt? == end ==

20 years, 9 months

[linux-audio-dev] Idea: fake OSS passback driver

by Daniel Risacher

I had an idea the other day, and I wanted to bounce it around for feedback before I invest any real time into it. While I have done some minor kernel hackng over the years, I am not experienced in the audio subject area. Background: Despite the various and sundry advances in linux audio, I find there are still legacy apps that are built against the OSS API. This is problematic since the legacy OSS model has blocking semantics. To get multiple audio streams, one must use an audio server such as esd, aRts, etc. Wouldn't it be nice if all the legacy apps "just worked"? Without blocking each other? Idea: Suppose one were to write a kernel module that implemented the OSS API, but had non-blocking semantics, and instead of driving a sound card, the module encapsulated the OSS API calls somehow and passed them back to a user-space audio server. Ao, for example: suppose we had a system with alsa and the proposed passback driver. xmms is playing via esd-passback-alsa, which is a modified version that supports input from the passback driver and outputs via alsa. The user fires up Ogle, which only has OSS output code (I'm not sure if this is true; just an example). /dev/dsp is the passback driver, and when ogle opens it, it succedes, even through someone else is using the sound card (esd). The passback driver "passes back" all of Ogle's ioctls to a modified version of esd, which, in turn multiplexes the audio with whatever else is playing (xmms, in this example), and plays it via alsa. I'm not precisely sure how I would to handle the actual "passing back". Probably a separate device file /dev/dsp-passback, which is read by the audio server. Can anyone say why this idea can not, or should not be implemented? Now that I've articulated the idea, would anyone care to take over the implementation?

20 years, 9 months

[linux-audio-dev] Cross platform mixer API?

by Eliot Blennerhassett

Greetings, I am aware of PortMixer, which is a simple API that abstracts volume controls. Is anyone aware of any other crossplatform, cross-API mixer abstraction layers out there? AudioScience is looking for/considering building a library that will wrap ALSA, audioscience HPI, windows WAVE, WDM mixers in a common API. If such a library doesn't exist, why is that? 1) Too hard 2) Too easy 3) No use 4) other? I'd welcome your comments. regards Eliot AudioScience Inc.

20 years, 9 months

[linux-audio-dev] [ANN] First public release of Lindrum v 0.5.1

by peschler＠t-online.de

Hi LADs, Lindrum is an open-source drummachine that offers ten channels, realtime control, a simple pattern sequencer and a graphical user-interface. It currently runs under Linux only, it is developed in C++ and uses JACK, ALSA, Qt and LADSPA. More infos and downloads can be found at: http://www.sinussource.de/lindrum/ This is the first public release, so i am strongly interested in any kind of feedback. I also want to thank all the people on this list for their excellent work, you're the ones who made and make developing audio applications under linux so cool. Keep it going! Btw: Lindrum uses two selfmade C++ wrapper libraries called jackpp and ladspapp. They are contained in the lindrum tarball. Since they might be interesting standalone too, they are available as separate tarballs at the above url (check the end of the page). Bye and have fun, Peter Eschler -- "Without music, life would _O_/ \_O_/ +----------------------+ be a mistake - I would / )) [] | Peter Eschler | only believe in a god who \\ // | peschler(a)t-online.de | knew how to dance." (Nietzsche) // \\ +----------------------+

20 years, 9 months

[linux-audio-dev] Linux Audio Experiences

by Dan Harper

Hi all (sorry for the cross-post, but this may not be just a problem with Ardour), Over the last week and the weekend, I took to recording a song in full using Jack, Hydrogen, Ardour and Jamin. I'm not sure if Ardour/LAD is the best place to send this, but some things that I noticed may be across different software, but I thought I'd list a few issues that came up, as well as some delights. I'm not on the Jack or Hydrogen lists, but if this is a Jack or Hydrogen problem, please let me know and I'll post it there. The main problem I had was the sync between Hydrogen and Arodur. I had Hydrogen set as Jack transport slave, and Ardour as master. Both programs were set at 130 bpm, but if I recorded something to a track in Ardour, and then played it back, it sounded fine (in time), but on the screen, the recorded material does not line up with the bar lines in Ardour. The recorded stuff appears a few millimetres before the bar line. Another interesting thing was if I changed the (period?) in Jack from 512 to 1024, the Hydrogen playback was out of time to the Ardour playback, if I switched it back to the original setting it was recorded in, it was fine. I had a few stability problems, but I didn't test them very much, it seemed to be realted to having certain plugins enabled in Ardour. Jack was kicking Ardour out when a particular plugin was being used. I'll have to test that another time to get more detail. Overall though, things went fairly smoothly. The result of the weekend is available at http://danharper.org/songs.php if anyone is interested. It was all done in Linux: HYDROGEN -> ARDOUR ------------------------> JAMIN -> QARECORD Electric Guitar (3 tracks) Vocals (3 tracks) Bass Guitar Vocals Bus Hydrogen Out to an Ardour Bus Master Bus Feel free to give feedback on the song, mix, and mastering. One thing that I loved was Jack. Getting a nice sounding mix and master was so easy because I could change a track level in Hydrogen, and immediately hear the results through Jamin. Same also if I needed to change a plugin parameter or track level in Ardour, the results were immediate. There is no other set of audio tools around that I know of that can do this. A very powerful and useful feature of the design of Jack and its clients. Overall, I should mention that the majority of my time was spent wrestling with LADSPA plugins. Some cased reliability issues in Ardour (see above, more info to come). Some gave me some OK sounds, but I have noticed in the mixdown that the guitar orverdrive doesn't have a nice warm sound. I can't recall the exact plugins I used from memory, but I did find it hard to find plugins that would give me a nice warm sound on guitar tracks. Maybe that is something to improve upon. Dan

20 years, 9 months

[linux-audio-dev] liblo first release (0.2)

by Steve Harris

http://plugin.org.uk/liblo/ liblo is a simple to use, lightweight OSC C library implementation (http://www.cnmat.berkeley.edu/OpenSoundControl/) chasnges since the pre-release include type coercion and API cleanups. this is a candidate release to get feedback on the API. usage example can be found in src/testlo.c - Steve

20 years, 9 months

[linux-audio-dev] oss2jack 0.13: A kernel-based approach to using OSS applications with jackd

by Kor Nielsen

Hi, I have been quite frustrated with the difficulty of getting multiple OSS applications using my sound hardware simultaneously. The LD_PRELOAD hacks that I have tried leave much to be desired in terms of usability, especially when dealing with arts and mozilla plugins. oss2jack uses Jeremy Elson's useful fusd library (http://www.circlemud.org/~jelson/software/fusd/) to create a userspace character device, which is also a jackd client. It supports mono and stereo streams, with virtually any sample rate thanks to libsamplerate (http://www.mega-nerd.com/SRC/). Only the commonly-used OSS ioctls are currently supported. I have tested oss2jack with the following applications, and they behave fairly well: - mplayer - artsd (and thus all the kde applications) - xmms - Macromedia Flash TODO: - support mmap for quake and other games (requires support in fusd) - detect jackd period for audio sync (currently assumes 64 samples). Should not be too noticeable unless you get above a 256 sample period) - lower CPU usage with artsd by blocking until the minimum fragment size is available (rather than the jackd period) - support for the OSS mixer. Available at: http://fort.xdas.com/~kor/oss2jack/ WARNING: I have not yet tested oss2jack on the 2.4 series kernel. Currently I am using a self-created 2.6 patch for fusd available at the site above. It has been stable for the past 3 weeks on my machine, but no guarantees about stability or safety... :) fusd currently requires that devfs be enabled in the kernel. Any comments are appreciated. Kor

20 years, 9 months

[linux-audio-dev] DRC 2.4.0

by Denis Sbragion

Hello, DRC 2.4.0 has been released and it is available at: http://freshmeat.net/projects/drc/ Changes in this release: The Takuya Ooura and GNU Scientific Library FFT routines have been included in the program. These routines are about 10 times faster than the previous routines, providing about the same accuracy. Best of listening, -- Denis Sbragion InfoTecna Tel: +39 0362 805396, Fax: +39 0362 805404 URL: http://www.infotecna.it

20 years, 9 months

[linux-audio-dev] ICMC 2004: Grace Period for Deadline of Submissions

by tae hong park

Please pardon cross postings. The ICMC 2004 submission deadline for music, video art, and installations which was originally February 27, 2004 has been changed to reflect an additional grace period of two business days. The updated submissions deadline for music, video art, and installations is now March 2, 2004 (Tuesday). Please note that this is the receipt deadline and not postmark deadline. The deadline for papers, posters, roundtables, and demonstrations have not changed and are to be submitted by midnight EST, Friday, March 12, 2004. Forms, submission guidelines, and further details are available at http://www.icmc2004.org. Thank you. Best Regards, Tae Hong Park, ICMC 2004 Publicity Chair

20 years, 9 months

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Linux-audio-dev February 2004