Linux-audio-user August 2005

linux-audio-user@lists.linuxaudio.org

169 participants
209 discussions

by Dirk Ouellette

Yes, as long as you (or an init script) runs "alsactl restore" on the next boot. Save/restore mixer settings should work OOTB with any decent distro, normal users should never have to use alsactl. So how and where do I put this in an init script?

19 years, 3 months

[linux-audio-user] Re: Resampling Audio Libraries & Sinc

by Item State

i happened to have a short glimpse on your posting, david. i don't want to insult anyone, but there is a bit more to evaluating accuracy than comparing sample values at fixed locations ;--))))))) consider a few of these things : a) non-causal algorithms introduce a natural delay. for windowed sync interpolators this is half of the filter kernel. ok, the algorithm could skip those samples of course (that's what fscape is doing by the way, if i remember correct). b) the algorithm could introduce a gain factor different from 1.0, this is in fact very likely, consider resampling 44.1 khz to 22.05 khz, a 0 dB headroom file would be distorted if there is no gain compensation. c) the crucial point about windowed sync is that it's naturally also a lowpass filter (for upsampling which you were doing in your example). so, those filters are windowed sync filters, they are linear phase and show an effect called gibbs effect which means "edges" show pre and post ringing phenomena. this is not necessarily "bad" and with not extremely long kernels it's not audible, too. in fact, when you run a software synthesizer you will most likely want band limited oscillators, i.e. those with gibbs effect. now, no realizable filter is infinitely steep, so you'll have a passband etc. summa summarum it's very likely that for an arbitrary input sound, resampling with an integer factor will *not* produce equal sample values with the factor spacing in the output. without blowing up this stupid discussion, i suggest to do two things : a) *listen* to the results for an aural comparison. this is in fact the most important point, because for different ears different algorithms are better or worse. i, for example, use bandlimited resampling in most cases and in real resamping cases (e.g. 48 kHz -> 44.1 kHz), but sometimes i prefer the additional colouring and brightening (= distortion) of say cubic interpolations or even linear interpolations which produce the hardware-sampler-kind-of-timbre. b) read a book about audio analysis, and perform some more appropriate tests, for example calculate the harmonic distortion (try your example with a sine tone!). best, -sciss- ___________________________________________________________ Gesendet von Yahoo! Mail - Jetzt mit 1GB Speicher kostenlos - Hier anmelden: http://mail.yahoo.de

19 years, 3 months

[linux-audio-user] [ANN] Mondrian Project

by Peter Brinkmann

All: I would like to announce the Mondrian Project. Mondrian is an attempt to create a text-based setting for writing and performing music. It currently consists of the following parts: - a simple music description language intended to be small and keystroke efficient - a Mondrian-to-MIDI converter - interactive sequencers intended to play Mondrian code in a live performance - sequencer plugins for vi and emacs that turn text editors into musical instruments You can find Mondrian at http://www.math.tu-berlin.de/~brinkman/software/mondrian/ There's an online demo that'll let you try the language without the need to install anything. Any feedback would be appreciated! Peter

19 years, 3 months

[linux-audio-user] Academic question about AMD64 and audio

by thewade

Hello, I have a purely academic question stemming from an accidental install on my part: Will my AMD64 laptop run PD and other sound apps (using mingo's RT patched kernels) faster in native 64-bit linux or faster as a conventional 32-bit linux? I ask this because I am about to install the "correct" 64-bit linux but I will then have array problems and other PD errors that have not yet been solved... So if my machine is faster in 64 -bit linux the shortcommings of 64-bit PD are outweighed by the speed gain. Thanks all! -thewade

19 years, 3 months

[linux-audio-user] Re: MIDI test

by Kevin Sookocheff

> Just to be sure: this is the MIDI/gameport on the mainboard? Yep. > What ALSA version are you using? Advanced Linux Sound Architecture Driver Version 1.0.9rc2 (Thu Mar 24 10:33:39 2005 UTC). > What kernel version? Linux demudi 2.6.12-3-multimedia-k7 #1 Thu Jun 23 12:52:11 CEST 2005 i686 GNU/Linux I just installed the latest version of Demudi, and I haven't really done much to the default install yet. I've got the following etc/modules: snd-seq-midi ide-cd ide-disk ide-generic psmouse And I'm not sure what options are set for snd-mpu401, and don't know how to find out. Thanks, Kevin

19 years, 3 months

[linux-audio-user] OPen source Music 100%

by studio-64

HI All Hopefully the right link now , sorry : You should just be able to play/download the mp3. http://www.soundclick.com/bands/songInfo.cfm?bandID=390090&songID=2785733 This is causing quite a stir on some of the more windows sites, to say the least! Mostly I get: Whats Ardour and can I where can I get it? Must be that taste of Freedom they hear! Cheers Bob bearmusic

19 years, 3 months

[linux-audio-user] Using pd with Wacom Intuos 2 in Linux

by Jerome Tuncer

First: sorry for crossposting on two lists (inux-audio-user; pd-list), hope it doesn't bother anyone... Second thing: hello! Third thing: the facts: I now own a Wacom Intuos 2 tablet which I'd like to use with Pure Data just like a MIDI controller. I plugged the thing in my PC equipped with Ubuntu Hoary (kernel 2.6.10-5 included in the distro) and it works plugnplay out of the box as a mouse would ("pointing device" seems to be the scientific name for that stuff). The two things I'd like to be able to do are: - Stop using the tablet as a pointing device. To make it simple: I'd like it to stop moving my cursor over the screen! - Be able anyway to input data into Pd (x, y, pressure would be an appreciated plus...) If it is possible to do, I'm sure someone has done it already. If I'm lucky he reads the lists... How should I procede? Thanks in advance... ++ Jé

19 years, 3 months

[linux-audio-user] Resampling Audio Libraries & Sinc Resamplers

by davidrclark＠earthlink.net

Part 1 of (maybe) 3 Some time ago, a question was asked on LAU regarding resampling of an audio library. I strongly recommend the following, assuming that you decide to resample (and that's your call, not anyone else's): If you can at all avoid it, *don't* use sinc resamplers (for example, sndfile-resample and resample-1.7) for bulk rate conversions at constant rates, especially for resampling something of great value such as an audio library which you plan to use over and over again on future projects. To be most certain you've got a good library at the new sample rate, re-record the original sources or purchase a competently produced new library. ------------------------ In answering this question about resampling an entire audio library, Steve Harris (prolific author of LADSPA plugins for which we are all grateful) posted: "I would say that a high quality sinc resampler will be the best quality." Upon contacting Steve and exchanging several emails, it became clear that Steve was actually talking about the theoretically ideal case, not about the algorithm developed and described by Julius O. Smith III of CCRMA and implemented in such codes as sndfile-resample and resample-1.7. Steve says he doesn't have enough experience with these programs to either agree or disagree with claims made about them. For many readers, "sinc resamplers" probably does refer to these programs, so I think it's important to attempt once again to put them into perspective: Julius O. Smith III of CCRMA, in his PDF document describing a sinc- function based algorithm in detail, himself mentioned the suitability of this particular algorithm for situations wherein the sampling rate was *changing* and *arbitrary* such as audio scrubbing, a real-time application of resampling. Resampling an audio library is an application of *bulk conversion* to a *fixed sample rate* and is very different, therefore, as is easily arguable, an unsuitable application for Smith's algorithm, therefore unsuitable for sndfile-resample and resample-1.7. I may demonstrate some problems with bulk conversions later such as I did for Steve, but first should point out that anyone who is familiar with Fourier analysis and synthesis should appreciate immediately why this is the case upon reading Smith's description of the algorithm: As described in [1] it utilizes very small, comparatively infinitesimal windows (compared to the infinite signals of the Sampling Theorem) and is of order n squared. For someone with the proper education and/or experience, this is really *all that is necessary to know* to predict problems with speed or accuracy --- or both of these. ------------------------ Reference [1] Julius Orion Smith III. Digital Audio Resampling Home Page. http://www-ccrma.stanford.edu/~jos/resample/. This reference cites (after reordering author/title): J. O. Smith and P. Gossett. Flexible Sampling-Rate Conversion Method. In Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, March 1984 (ICASSP-84), Volume II, pp. 19.4.1-19.4.2, IEEE Press. Note the word "flexible."

19 years, 3 months

[linux-audio-user] More music

by james＠dis-dot-dat.net

Something miserable for a miserable day. http://www.dis-dot-dat.net/content/music/socold.ogg Also available in mp3 flavour. -- "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)

19 years, 3 months

Re: [linux-audio-user] linux audio wiki - (was usb controllerkeyboards)

by perezmeyer＠infovia.com.ar

Original Message: ----------------- From: Christoph Eckert ce(a)christeck.de [snip] > * linuxaudiowiki.org > * linuxaudio.org > * freeaudiosoftware.org > > Further ideas? libreaudiosoftware.org would perhaps be more "correct", but I still prefer freeaudiosoftware.org . Cheers, Damian.- -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ .

19 years, 3 months

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Linux-audio-user August 2005