Linux-audio-dev

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7516 discussions

Re: Re: [linux-audio-dev] more practical stuff about synth-programming -- jack seems to be less documentated

by hexe_2003＠directbox.com

-------- directBOX Reply --------------- From: paul(a)linuxaudiosystems.com To : linux-audio-dev(a)music.columbia.edu Date: 18.09.2003 15:00:29 >It allows you to get a basic DSP algorithm producing sound without you >worrying about how to configure the audio interface, and then later >lets that same output be (potentially) routed to other applications >for processing/manipulation/recording. Well, this sounds very interesting; but where can I find developers documentation about jack ? Like I said, the Homepage is not interesting for that part of information need... . And has anybody some interesting c-algorythm documentation on how to produce convolution ? I mean: oscilating basing wave -> mix it together with a lfo -> filter it with delay, for example -> ... greetz, Sascha Retzki __________________________________________________ Verpassen Sie keine eBay-Auktion und bieten Sie bequem und schnell über das Telefon mit http://www.telefonbieten.de Ihre eMails auf dem Handy lesen - ohne Zeitverlust - 24h/Tag eMail, FAX, SMS, VoiceMail mit http://www.directbox.com

22 years, 1 month

Re: [linux-audio-dev] lowlatency test at linuxdevices

by Benno Senoner

Paul Davis wrote: > I hope this is not true: > > "Embedded systems often need to poll hardware or do other tasks on a > fixed schedule. POSIX timers make it easy to arrange any task to get > scheduled periodically. The clock that the timer uses can be set to > tick at a rate a fine as one kilohertz, so that software engineers can > control the scheduling of tasks with precision." > The promise of the high-res timer patch was usec resolution, not msec. > This would be a great loss. Does anybody know any more? Yes unfortunately it is true what they say in the article. The current timer resolution is 1msec (HZ = 1024, so to be precise the resolution is (1/1024) sec). In short the story is as follows: Linus accepted the POSIX 1003.1b Section 14 (Clocks and Timers) API in kernel 2.6 but not yet it's implementation (patches available here http://high-res-timers.sourceforge.net/ ). This means that applications using the POSIX 1003.1b timer API can specify timing values nanosecond resolution but for now only msec resolution is provided. But when the Linus & co will let in the kernel the high-res timer implementation, those apps will instantly be able to achieve higher resolution without recompilation etc. Yes usec resolution would be handy for some audio apps but I for now I am happy of being able to achieve msec resolution in MIDI playback without resorting to the RTC device which cannot easily be shared. PS: in the article they talk about 4500usec worst case scheduling latency (= 4.5msec), seems a bit disappointing. I'm curious what they mean with worst case, which kind of test suites they used etc. 2.4 + some LL patches let you reliably work with sub 3msec BTW. Benno ------------------------------------------------- This mail sent through http://www.gardena.net

22 years, 1 month

[linux-audio-dev] [ANN] Lemux version 0.2

by Joost Yervante Damad

Lemux is a collection of (GPL) LADSPA instruments based on devices from the openMSX emulator and other sources (e.g. sidplay2). Changes against 0.1: - all instruments are working, currently: - SCCChannel (e.g. from Konami games) (a 32 byte 8bit looped samples instrument) - PSGChannel (the standard sound chip from MSX) (a 1/2 square wave with noise and AM) - MUSICChannel (the FM OPLL chip from MSX-MUSIC) (a 2 operator FM chip, with 15 standard instruments and 1 custom FM instrument that is fully configurable) - MUSICDrum (FM OPLL Drums) (5 standard drum sounds from OPLL) - SID (The full C64 audio chip) - instrument volumes are now normalized More info (and audio samples) can be found at the website: http://lumatec.be/joost/lemux/ Greetings, Joost Damad

22 years, 1 month

[linux-audio-dev] Streaming compressed audio from the network

by Juhana Sadeharju

Hello. If I understood correctly, several companies are wanting patent royalties for streaming compressed audio from the network. Take a look at mpg321 (GPL clone of mpg123): Usage: mpg123 [options] file(s) | URL(s) | - So, this playing from the network URLs is no no, or what? What other software are able to play a compressed audio from the network? Juhana

22 years, 1 month

[linux-audio-dev] next power of two

by Maarten de Boer

Hi, A colleague of mine found this very clever algoritm to calculate the next power of two for a given number. It comes from the Prophecy SDK for 3d game development http://www.twilight3d.com/modules.php?op=modload&name=Downloads&file=index Since this is a kind of thing often needed in audio processing, I wanted to share it with you. I certainly can not think of a faster (or more elegant) way of doing it. Maarten ////// /// Returns the closest power-of-two number greater or equal /// to n for the given (unsigned) integer n. /// Will return 0 when n = 0 and 1 when n = 1. ////// inline uint32_t nextPowerOfTwo(uint32_t n) { --n; n |= n >> 16; n |= n >> 8; n |= n >> 4; n |= n >> 2; n |= n >> 1; ++n; return n; }

22 years, 1 month

Re: [linux-audio-dev] next power of two

by Taybin Rutkin

Heh, that doesn't sound very RISC-like to me... Taybin -----Original Message----- From: Maarten de Boer <mdeboer(a)iua.upf.es> Sent: Sep 18, 2003 7:41 AM To: linux-audio-dev(a)music.columbia.edu Subject: Re: [linux-audio-dev] next power of two By the way, it seems the PPC has instructions to do it. >From the "PPC compiler writers guide": Round Up or Down to Next Power of 2 The floor power of 2 ( flp2) and ceiling power of 2 ( clp2) functions are similar to the floor and ceiling functions, respectively, but they round to an integral power of 2, rather than to an integer.

22 years, 1 month

[linux-audio-dev] more practical stuff about synth-programming -- jack seems to be less documentated

by hexe_2003＠directbox.com

( This email is a reply to one of my threads; but I deleted the originally mail, so I open another; to original thread asked you for some background information about pcm-data ...) hi, First I want to thank you for the ideas ( http://www.dspguide.com ; http://www.amazona.de ) ; and well, I am from Germany, so German articles are not bad :) But both are very theoretically. Both are very good, both are very interesting. I've not even finished both completely, because its much information you gave me... I'll see what I can really use in my little programme... . If you know something interesting stuff to programm a software (!) synthesizer, let me know :) . Somebody of this list said to me that "it would be much easier for me to use jack" . Well, I did not find ANY developer-documentation on the originally HP and I want to know if jack already HAS an easy-to-programm software synth implemented; If yes, where can I find further information ? ( I know that some of my questions could be answered by google, but I ALWAYS give it the wrong keywords :)) ) Greetz, Sascha Retzki __________________________________________________ Verpassen Sie keine eBay-Auktion und bieten Sie bequem und schnell über das Telefon mit http://www.telefonbieten.de Ihre eMails auf dem Handy lesen - ohne Zeitverlust - 24h/Tag eMail, FAX, SMS, VoiceMail mit http://www.directbox.com

22 years, 1 month

[linux-audio-dev] lowlatency test at linuxdevices

by Robert Jonsson

Hi, First I must admit right away, I only looked at the pretty pictures so far, but they where sufficiently nice for me to post it here ;-P. http://linuxdevices.com/articles/AT7751365763.html /Robert

22 years, 1 month

RE: [linux-audio-dev] next power of two

by Hannes Guddat

Very interesting, "in the name of all DSP programmers" - thanksalot! Do you have any estimation how many cycles this would spend on a pentium? I would have make a wild guess of about 16-21 cycles + call overhead (if not inlined).. Hannes P.S. Maybe you have similar code for the "bitreverse" operation.. ? just asking.. :) // // we apologize for the inconvenience // // Hannes Guddat // Fraunhofer IGD // A9 - Communication and Cooperation // Rundeturmstrasse 6 // 64283 Darmstadt // // Tel.: +49 6151 155-217 // Fax.: +49 6151 155-559 // > -----Original Message----- > From: linux-audio-dev-admin(a)music.columbia.edu > [mailto:linux-audio-dev-admin@music.columbia.edu]On Behalf Of > Maarten de > Boer > Sent: Mittwoch, 17. September 2003 14:22 > To: linux-audio-dev(a)music.columbia.edu > Subject: [linux-audio-dev] next power of two > > > Hi, > > A colleague of mine found this very clever algoritm to calculate the > next power of two for a given number. It comes from the > Prophecy SDK for > 3d game development > http://www.twilight3d.com/modules.php?op=modload&name=Download > s&file=index > > Since this is a kind of thing often needed in audio > processing, I wanted > to share it with you. I certainly can not think of a faster (or more > elegant) way of doing it. > > Maarten > > ////// > /// Returns the closest power-of-two number greater or equal > /// to n for the given (unsigned) integer n. > /// Will return 0 when n = 0 and 1 when n = 1. > ////// > inline uint32_t nextPowerOfTwo(uint32_t n) > { > --n; > n |= n >> 16; > n |= n >> 8; > n |= n >> 4; > n |= n >> 2; > n |= n >> 1; > ++n; > return n; > } >

22 years, 1 month

[linux-audio-dev] [ANN] Gungirl Sequencer 0.1

by Richard Spindler

Hi, this is the first Release of My new Linux Audio Sequencer. Gungirl Sequencer is an easy to use Audiosequencer. It includes a simple Filemanager and uses Drag & Drop to arrange Audiosamples. For more Information see http://homepage.uibk.ac.at/~csad2715/ggseq/

22 years, 1 month

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Linux-audio-dev