Linux-audio-dev March 2007

linux-audio-dev@lists.linuxaudio.org

79 participants
63 discussions

[linux-audio-dev] Re: [linux-audio-user] LAC Recording Guidelines

by Marc-Olivier Barre

On 3/5/07, nescivi <nescivi(a)gmail.com> wrote: > Hi Esben, > > Monday, March 5, 2007, 3:47:08 AM, you wrote: > > ES> It would be nice with some recording guidelines for LAC. Both for > ES> video and for audio. > > ES> Maybe post a mail to linux-graphics-dev;). > > ES> I'm talking about issues such as telling the participants to use big > ES> text on the slides. Maybe also, if the person is on the right side, > ES> maybe a vector overlay could be done, cheaply. > > I will inform the authors. > But also note, the slides will be available as pdf's from the LAC > website as well. So there are readable versions of the slides > available. > > ES> It's also wise to position the camera such that there is little > ES> movement other than the speaker. This would save bandwidth and allow > ES> us to use higher resolution. Also, to not move the camera is nice. > > ES> Also, to not allow questions from the audience without a microphone;). > > This we always try, but sometimes the questions are so burning that > they can't wait for the microphone... > > > ES> There are also many issues recording the speaker. > > Any tips are welcome. > As far as I understood from Jörn there were some problems to multiplex > the audio stream with the video stream, so they had to use the > mic-input from the camera. If you know of a good solution where we can > do the multiplexing with the audio stream from the mixing desk > properly, then please share your experience! > > sincerely, > Marije Jörn is very welcome to raise the issues he has on this list. Eventually someone will give a good hint ;-) I'm sure a lot of people far away from berlin would like to be able to give a helpful hand. And I would be surprised if there was no way to multiplex an audio stream... Cheers, __________________ Marc-Olivier Barre, Markinoko.

17 years, 9 months

[linux-audio-dev] new releases

by Fons Adriaensen

New releases of JAAA and JAPA and the libraries they depend on are now available at <http://www.kokkinizita.net/linuxaudio/downloads> jaaa-0.4.1: bugfixes. japa-0.2.0: bugfixes, white and pink noise generators now built-in. clalsadrv-1.2.1: bugfixes. This version should now work correctly with ALSA's default multi-client device. clxclient-3.3.2: bugfixes. There are also some (essential) bugfixes to the HOA-NF filter code. -- FA Lascia la spina, cogli la rosa.

17 years, 9 months

[linux-audio-dev] scaling audio signal

by Silver Rock

Hi People, On trying to deal with wave files in python, I came across this article: http://209.85.165.104/search?q=cache:vMIuboZw0BwJ:scipy.mit.edu/tutorials/w… the original pdf http://scipy.mit.edu/tutorials/wave.pdf is not available... The signal scaling is just beyond my understandings, and I can´t find any explanation on the web about it. What is the role of that in the programm? Anyway, I will write here what it does to the audio signal that I don´t understand. By catching code lines in functions it looks like this: '''' mono signal, a list, say a 200Hz sinusoid with 2 seconds): signal=[math.sin(2*math.pi*200*(x/44100.0)) for x in range(88200)] ''' tmp = list( signal ) min_tmp = min(tmp) max_tmp = max(tmp) scalar = (2**16 - 1.0) / (1.0 * (max_tmp - min_tmp)) * volume #for 16 bit, it could be 8 or 32 tmp = map( lambda x: int(scalar*(x-min_tmp)), tmp) signal = tmp if samp_width != 1: signal = map( lambda x: x - 2**(samp_width*8 - 1), signal ) #and then they pack the code, conv_code is 'B' for 8 bit, 'h' for 16 bit, 'i' for 32 bit: f.writeframes( struct.pack( conv_code, signal[i] ) ) Ok. This struct thing I don´t fully understand, but I already know it has to do with C data strings. But the previous part simply doesn´t make sense, and I can´t find any reference to this things on the web. I would really appreciate if anyone could explain me what is happening and/or point me some writings about that. One disturbuing thing about using this script is that sometimes it outputs a wave file with start and end out of center (zero amplitude), even when the singal list had fadings. It seems that it has to do with signals that goes beyond the [-1,1] closed interval, but I don´t know why. thanks guys, Claire

17 years, 9 months

[linux-audio-dev] RE: [linux-audio-user] Open letter to Steve Ballmer

by Jan Depner

I normally wouldn't reply but this is way off. If there is prior art then the patent can be thrown out. This is what PubPat is doing and what was attempted with the Microsoft FAT patent (and succeeded in Germany). If Microsoft took out a patent on something that was implemented previously in ALSA code but they did not steal the code from ALSA they are not required to GPL anything. GPL is a license based on copyright. As long as they don't copy the code they're not breaking any laws and, unless someone can prove that they copied the code, they ar enot required to reveal it. Jan On Fri, 2007-03-02 at 14:37 +0100, Nick Copeland wrote: > If Microsoft patent any capabilities that are present in the ALSA codestream > them ALSA itself is exempt from the patent. This is written into the patent > laws, they cover the possibliity that somebody had a product that was later > patented by some other, wiser party. If the company in potential infringment > can prove prior implementation then they are exempt. > > The exact wording of the exemption would probably require legal > interpretation, however if Microsoft have patents applied for that cover > features already implemented by ALSA then not only are implementations of > the ALSA driver exempt (prior implementation can be proven based on driver > distribution dates to precede the patent application) but at the same time > there is a seperate issue that if Microsoft did take out a patent of an ALSA > capability then under the terms of the GPL they may legally be required to > make their code publicly available as it arguably must have been based on > the open sourced capabilities. > > Regards. > > >From: "Marc-Olivier Barre" <mobarre(a)gmail.com> > >Reply-To: A list for linux audio users > ><linux-audio-user(a)music.columbia.edu> > >To: "Linux Audio Dev List" <linux-audio-dev(a)music.columbia.edu>,"A list for > >linux audio users" <linux-audio-user(a)music.columbia.edu> > >Subject: [linux-audio-user] Open letter to Steve Ballmer > >Date: Fri, 2 Mar 2007 12:09:25 +0100 > > > >Hi, > > > >Since Microsoft recent audio related patent "that looks a lot like > >ALSA", I thought this could be interesting : > > > >http://www.showusthecode.com/ > > > >In short it's an open letter to Steve Ballmer asking him to show the > >code and patents that Linux supposedly copied from Microsoft (haha, > >what a joke...) > > > >Happy reading, > >__________________ > >Marc-Olivier Barre, > >Markinoko. > > _________________________________________________________________ > Don't just search. Find. Check out the new MSN Search! > http://search.msn.click-url.com/go/onm00200636ave/direct/01/ > -- Jan 'Evil Twin' Depner http://myweb.cableone.net/eviltwin69 "Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, chardonnay in one hand, chocolate in the other, body thoroughly used up, totally worn out, and screaming 'WOO HOO, what a ride'"

17 years, 9 months

[linux-audio-dev] [ANN] hexter 0.6.0

by Sean Bolton

Announcing a new release of the hexter DSSI plugin. http://sourceforge.net/project/showfiles.php? group_id=104230&package_id=134428 hexter is a software synthesizer that models the sound generation of a Yamaha DX7 synthesizer. It can easily load most DX7 patch bank files, accept patch editing commands via MIDI sys-ex messages, and recreate the sound of the DX7 with greater accuracy than any other open-source emulation (that the author is aware of...) hexter operates as a plugin for the Disposable Soft Synth Interface (DSSI). New features in version 0.6.0 include: * Implemented the LFO, amplitude modulation and pitch modulation (many thanks to Jamie Bullock)! * Added TX7-style performance parameters, allowing configuration from the GUI of pitch bend range, portamento time, and sensitivity and assignment of the modulation wheel, foot controller, pressure (both channel and key), and breath controller. * Added DX7 patchbank loading code from Martin Tarenskeen, allowing hexter to load a number of additional patch file formats. * Partially implemented portamento. For now, the curves and times are wrong, but the plumbing is there. More information about hexter and DSSI can be found at: http://dssi.sourceforge.net/hexter.html hexter is written by Sean Bolton, and copyright (c)2007 under the GNU General Public License, version 2 or later.

17 years, 9 months

[linux-audio-dev] jackmidi_alsaseq-0.4

by Dmitry Baikov

Just can't resist. ---------- Forwarded message ---------- From: Dmitry Baikov <dsbaikov(a)gmail.com> Date: Mar 2, 2007 3:59 AM Subject: jackmidi_alsaseq-0.4 To: Jack Dev List <jackit-devel(a)lists.sourceforge.net> After missing several deadlines, we are finally here. This is the latest and greatest release of jackmidi alsaseq bridge. It is getting ready for inclusion into jackd (I hope), and I'd like to test is as hard as possible. I hope you will help me here :) Everything it needs is an svn version of jackd. For timing it by default uses hrtimers (available on 2.6.19+), there 3 more variants for your pleasure: select, poll and alsa queues. To enable them, uncomment corresponding define in the beginning of alsa_seqmidi.c. Although, hrtimers (via clock_nanosleep) shows the best results. Alsa queues suffer from events reordering, unless used with jack_time.patch. This is NOT a problem of alsa-seq, but is nearly impossible to avoid. To sum up, the default setting (clock_nanosleep) gives the best results so far. Regards, Dmitry.

17 years, 9 months

[linux-audio-dev] Re: [linux-audio-user] Open letter to Steve Ballmer

by Lee Revell

On 3/2/07, Nick Copeland <nickycopeland(a)hotmail.com> wrote: > If Microsoft patent any capabilities that are present in the ALSA codestream > them ALSA itself is exempt from the patent. This is written into the patent > laws, they cover the possibliity that somebody had a product that was later > patented by some other, wiser party. If the company in potential infringment > can prove prior implementation then they are exempt. > Prior art doesn't exempt the first implementor, it invalidates the patent, at least in the US. Lee

17 years, 9 months

[linux-audio-dev] Open letter to Steve Ballmer

by Marc-Olivier Barre

Hi, Since Microsoft recent audio related patent "that looks a lot like ALSA", I thought this could be interesting : http://www.showusthecode.com/ In short it's an open letter to Steve Ballmer asking him to show the code and patents that Linux supposedly copied from Microsoft (haha, what a joke...) Happy reading, __________________ Marc-Olivier Barre, Markinoko.

17 years, 9 months

[linux-audio-dev] Can we use Gmail on the new site

by Frank Smith

HI All my mail gets stopped as I'm using Gmail. This is an issue with older sendmail filters I believe. Cheers Bob

17 years, 9 months

[linux-audio-dev] variable audio stream ?

by Dominique Michel

After the bug fixes release of Alsaplayer, the hard work has begun. A discussion comes on our todo list in regards with new input plugins. We have an experimental wavpack plugin that constantly check the frame size. Does anyone ever hear about streams with variable byte-per-sample and frequency parameters (for example, at start it was 16bit/2ch/44100 but in the middle it will be 24bit/5ch/48000)? (for wavpack or other formats as well) Ciao, Dominique

17 years, 9 months

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Linux-audio-dev March 2007