Linux-audio-dev

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7441 discussions

[linux-audio-dev] Re: soundtracker / jack output

by majik

>Hi Majik, > >majik wrote: > >>---Here is an email I sent a little while ago to Kai Vehmanen: >> >> >> >>> I have been looking through the Soundtracker 0.6.7 code as I have >>> been >>>wanting to improve the jack output. It would be excellent if Soundtracker >>>could output each of its channels to a Jack port, instead of (as well as?) >>>outputting the mix the two mono channels. Unfortunately, Im only a beginner >>>when it comes to audio coding and was wondering if someone could hack it >>>together for me? >>> >>> >> >> >>---And his reponse: >> >>that would be a cool feature to have, but unfortunately not a trivial >>thing to add (though not impossible either). You could try to ask about >>this on the soundtracker mailing list (or possible on linux-audio-dev)... >>maybe someone else is also interested and has the time to help. >>Unfortunately I don't have much time for FOSS-development atm, so I'll >>have to pass. .( >> >> >>---Will anyone help with this? I believe that the problem is that the mixer >>code works in a monolithic way, thus needs a rewrite. >> >> >> >This issue's been discussed on the soundtracker mailing list, months ago. > >Here's a quote from Yury Aliaev, a Soundtracker contributor : > ><quote> >In the current state of ST such a thing (multichannel output) is almost >impossible because of the monolitic structure of the mixer code. The >optimal way to solve this is (I mean) rewriting the whole mixer in the >modular way. This also will make ST more flexible and universal and, in >particular, will make adding new effects (including LADSPA processing) >more easy. > >Currently I have some ideas how to do this (but still have no free time >for this :( ), but there is another way: libremix written by Conrad >Parker (see remix.sf.net) seems to be good for this purpose. ></quote> > > >A question I asked, a few weeks later : > ><quote> > >> About per track JACK outputs : In your answer to Emiliano Grilli, on >> june 1st, you explain that this needs a big rewrite. But do you >> believe a sort of hack is possible ? Like a small patch that lies >> around for those (I like JACK :) who need this feature before >> soundtracker engine gets rewritten... If yes, any advise ? Does it >> imply playing with the mixer assembly routines ? > ></quote> > >And Yury's answer : > ><quote> >Unfortunately, it will be a havy hack of assembler routines :( Because >they mix sounds from different channels directly after resampling, >rather then write to the separate buffers and then mix them. This is why >I decided to rewrite the mixer entirely rather then inventing kludges... ></quote> > > >Hope it helps... Yury may have started to rewrite the mixer. > >Regards > >-- > og Yes, I did see this, I just wanted to re-illuminate the topic and appeal through LAD to see if anyone did have some free time to develop this, as I feel it would be such a great feature. Matthew Carey

19 years, 5 months

[linux-audio-dev] E-MU 1212m Linux drivers

by Nicolas Mailhot

Dear sir, The HTPC market is growing and Linux has a strong presence here via software offerings like MythTV (http://www.mythtv.org/). A significant portion of HTPC users are interested in quality audio such as the one offered by professionnal sound cards. Simultaneously there is a drive to make kill all sources of low latency in the Linux kernel (http://lwn.net/Articles/120797/) to accomodate professionnal audio needs. Large professionnal Linux audio communities already exist (http://jackit.sourceforge.net/, http://www.linuxdj.com/audio/lad/) and the level of interest is high enough to be seen by some as driving the next major release of the Linux kernel (http://www.computerworld.com.au/index.php/id;669959914;fp;16;fpid;0 last §) Current Linux sound card support is good for mass-market products and high-end (RME, M-audio...) ones but no one has filled the intermediate audiophile/semi-pro/home-studio niche yet. The E-MU 1212m http://www.emu.com/products/product.asp?maincategory=754&category=754&produ… would seem to be ideally positionned to respond to this demand on the hardware side, except it has no Linux driver support right now. The Alsa project (http://www.alsa-project.org/) however has expressed interest on working on the problem provided they get an hardware sample. Since Alsa already develops drivers for other Creative sound cards with Creative support cooperating it would seem natural to expand the current partnership to the E-MU sound card family. I hope I made the case for such a partneship clear (I'm no native english speaker) and I'll soon be a happy Linux E-MU customer. Kind regards, -- Nicolas Mailhot

19 years, 5 months

[linux-audio-dev] Linuxtag 2005 audio booth participation II

by Christoph Eckert

Hi, we're currently four people for the linux audio booth. This is still too less because each of us wants to have some leisure time to visit other projects and talks. I think that six people is great, so at least three of them can always be at the booth. Even if you do not plan to be at Linuxtag over all the days your help is really welcome. So we're still looking for people who want to join us, mainly being at the booth, answering questions and demoing software. Information about the Linuxtag can be found on http://www.linuxtag.org/2005/en/home.html If you're interested, please contact me via personal mail. Thanks & best regards ce

19 years, 5 months

[linux-audio-dev] soundtracker / jack output

by majik

---Here is an email I sent a little while ago to Kai Vehmanen: > I have been looking through the Soundtracker 0.6.7 code as I have been > wanting to improve the jack output. It would be excellent if Soundtracker > could output each of its channels to a Jack port, instead of (as well as?) > outputting the mix the two mono channels. Unfortunately, Im only a beginner > when it comes to audio coding and was wondering if someone could hack it > together for me? ---And his reponse: that would be a cool feature to have, but unfortunately not a trivial thing to add (though not impossible either). You could try to ask about this on the soundtracker mailing list (or possible on linux-audio-dev)... maybe someone else is also interested and has the time to help. Unfortunately I don't have much time for FOSS-development atm, so I'll have to pass. .( ---Will anyone help with this? I believe that the problem is that the mixer code works in a monolithic way, thus needs a rewrite.

19 years, 5 months

[linux-audio-dev] Re: non-RT thread waiting for RT thread

by Juhana Sadeharju

>From: Andy Wingo <wingo(a)pobox.com> > >socketpair(2) will do, either polling or reading in the low priority >thread will sleep until the high priority thread writes a byte. I hope we get all the possible methods listed now. I have used signals for years in my alsashmrec. One process reads A/D to a ring buffer and another process empties the ring buffer to the disk. The problem was how to make the disk process (non-RT process) to wait. When the disk process has no data in the ring buffer, it goes to sleep: kill((pid_t)diskpid,SIGSTOP); When the A/D process has written enough data to the ring buffer, it wakes up the disk process: kill((pid_t)diskpid,SIGCONT); Because A/D process uses smaller buffer size, the A/D process is executed multiple times before SIGCONT is sent. Juhana -- http://music.columbia.edu/mailman/listinfo/linux-graphics-dev for developers of open source graphics software

19 years, 5 months

[linux-audio-dev] Call for Music made with Linux

by Florian Grote

The ZKM/DEGEM internet radio station (which hosted the LAC2005 concert streams) wants to produce a special on the conference. To fill this program with interesting music, I would ask all composers and musicians on this list to send me either links where a selected piece can be downloaded or directly mail an ogg or mp3-file. Please use the following address directly (so not to spam this list): audio(a)uni-lueneburg.de The ZKM/DEGEM internet radio will be launched at the "next generation" conference to be held at ZKM in June. The LAC2005 special will be on the program right away and will be streamed on a daily basis for one entire month. Both ZKM and DEGEM (German Society for Electroacoustic Music) are nonprofit organizations and submitted music will only be used for this single radio program. A link to the internet radio stream will be posted on this list as it becomes available. Thanks to everybody for cooperation, Florian Grote

19 years, 5 months

[linux-audio-dev] [ANN] KMidimon 0.1 (new) & KMetronome 0.5 (updated)

by Pedro Lopez-Cabanillas

KMidimon 0.1 ============ KMidimon is a MIDI monitor for Linux using ALSA sequencer, with KDE user interface. Quoting Dave Phillips in a three parts article for Linux Journal: "At some point, almost every serious MIDI musician needs to monitor a MIDI data stream, perhaps to diagnose a malfunctioning piece of equipment or to examine the contents of a MIDI sequence during playback". Features: * Easy to use KDE graphic user interface * Based on ALSA sequencer Provides one input port to be connected to other programs and devices using the usual external tools (aconnect, kaconnect, QJackCtl...) * Customizable event filters and sequencer parameters * Supports all MIDI messages, including System Exclusive, and ALSA messages * Saves to a text file (CSV format) the recorded event list * GPL licensed Provisional home page: http://kmetronome.sourceforge.net/kmidimon/ Download: http://prdownloads.sourceforge.net/kmetronome/kmidimon-0.1.tar.gz?download KMetronome 0.5 ============== KMetronome is a MIDI based metronome using the ALSA sequencer. This is a maintenance release fixing some compilation and runtime bugs. Please upgrade. Home page: http://kmetronome.sourceforge.net/ Download: http://prdownloads.sourceforge.net/kmetronome/kmetronome-0.5.tar.gz?download Changes ------- release 0.5 * autosave window settings (size...) * apply tempo/resolution when accept changes in configuration dialog * fixed bug in sequencerthread: set_program event must be direct. * other minor changes release 0.4 added features * Internal connection management now remembers the input port connection. * new setTempo and setTimeSignature functions added to the DCOP interface. fixed bugs * fixed compilation problem under Fedora Core 3 * fixed some automake problems

19 years, 5 months

[linux-audio-dev] non-RT thread waiting for RT thread

by Ken McMillan

I've been puzzling over something that I thought someone on this list might have a good solution for. I need to make a low priority (non-real time) thread wait for a real time thread to do something. I can't use a semaphore or condition variable for this, because that would mean the low priority thread must briefly take a lock while examining the condition variable or sempahore. If it were to be pre-empted while holding this lock, the RT thread could block waiting to obtain the lock in order to signal the condition or modify the semaphore. I could prevent this by raising the priority of the low priority thread before taking the lock, but I don't know how to do this in a portable way (i.e., I want my app to port to windows and mac, but even on "posix compliant" systems, getting RT privileges seems to be pretty system-dependent). It occurs to me that I could just "busy wait" using a timer, which would work but is a bit inelegant. Has anyone else come up with a good solution for this problem? Thanks for any thoughts -- Ken McMillan __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

19 years, 5 months

[linux-audio-dev] Re: Linux Audio Conference 2005 Live Audio/Video streams

by Luis Garrido

Hi! I downloaded a couple of recordings from http://www.linuxdj.com/audio/lad/contrib/zkm_meeting_2005/ The MuSE stream seems to have a big chunk of silence at the end (from min 28 on). There seems to be some problem with ardour stream beginning around min 76. Regards, Luis

19 years, 5 months

[linux-audio-dev] Other real-time options

by Jean-Marc Valin

Hi, After the debate regarding inclusion of realtime-lsm in the main tree, it seems like other approaches to unprivileged real-time have shown up. Both Con Kolivas and Ingo Molnar have come up with different (cleaner to the kernel developers) solutions. Both are described at: http://lwn.net/Articles/120024/ It seems like these solution have not been very popular yet, although I think they still have better chances of eventually being merged. I haven't tried Ingo's patch yet, but I can say that Con's SCHED_ISO_{FIFO,RR} (http://ck.kolivas.org/patches/SCHED_ISO/2.6.11.6-iso3.1.diff) works pretty good. Also, one nice feature that both approaches have is that you can set a limit on the amount of CPU a user RT task can use, preventing a user to lock up the machine. The way I see it, there are three important parts to a good solution: 1) Make sure no user can lockup the system with a "while(1);", so IMO realtime-lsm isn't the best solution (though I'm not strongly against) 2) Have per-user control, so that you can automatically restrict real-time tasks to only the person physically logged in. This would be important for a desktop configuration and would mean a distribution could enable this be default. 3) Making sure user tasks are lower priority that privileged tasks. Right now, Con's patch does 1 and 3, while Ingo's does 1 and 2 (though Con says Ingo's patch could also do 3). Would people here be happy with any of those and try to convince kernel developers that there's really a need for real-time (some still aren't convinced) and that one of these solution is acceptable? Jean-Marc -- Jean-Marc Valin <Jean-Marc.Valin(a)USherbrooke.ca> Université de Sherbrooke

19 years, 5 months

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Linux-audio-dev