Linux-audio-dev

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7516 discussions

[linux-audio-dev] shared memory question

by Dave Phillips

Greetings LADders: I'm working with Kjetil's vstserver, testing various plugins, and occasionally I get this error from the server : VSTSERVER/SMS_new: Unable to allocate 12288 bytes of shared memory. VSTSERVER/CH_new: Could not set up shared memory. The plugin then politely refuses to load. 'cat /proc/meminfo' reports : total: used: free: shared: buffers: cached: Mem: 526311424 511303680 15007744 0 70569984 234008576 Swap: 337195008 223801344 113393664 MemTotal: 513976 kB MemFree: 14656 kB MemShared: 0 kB Buffers: 68916 kB Cached: 208332 kB SwapCached: 20192 kB Active: 253612 kB Inactive: 177876 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 513976 kB LowFree: 14656 kB SwapTotal: 329292 kB SwapFree: 110736 kB I tried expanding the shared amount with 'echo some-big-number > /proc/sys/kernel/shmmax' but still got the error. I'm obviously not understanding something, so I turn to the wizards for help. Is there a fix for this problem ? Best regards, == dp

22 years, 1 month

Re: [linux-audio-dev] Best road to audio programming happiness?

by Juhana Sadeharju

Me too! For me Jack has been confusing as I'm not sure in what process/thread my audio routine runs. Somebody here wrote Jack's interesting thing is that it can route audio through applications. I don't want that. I want that Jack takes my C function (or its compiled object) and executes that within the real-time audio engine. Even if Jack is used, should one prepare process non-realtime audio within your own application. You cannot send background audio processings to Jack. Threads in the application are important because it is not good that the whole application freezes when one opens a big audiofile to editor, for example. I have not yet seen even moderate explanations or guides on those topics. We have discussed about Model-View-Controller (MVC) scheme, but nobody seemed to have any practical tool-level explanations so that I could easily use MVC in my applications. I suggest to start with Jack, not with Alsa or OSS. It took me an hour to write a Theremin synth, sort of. Very easy. (GUI was built with GTK+.) Best regards, Juhana

22 years, 1 month

[linux-audio-dev] Best road to audio programming happiness?

by Earle

I was hoping someone could help me with my first newbie steps in linux audio programming. I finally made it over to Linux, and discovered that I arrived here before cubase and fruityloops did. They never did what I wanted them to anyway. *sob*. Anyhoo, now that I'm over them, I would love to get cracking on some chunky audio projects but I'm a bit unsure of a kind of "best practises" approach for audio programming. What should I study? Whats the best way to go?! I have done some messing around with SDL and that seems pretty cool - cross platform, good graphic capabilites, and the audio is really simple. The faq says "low level support for audio" - is it low enough?! Is it useless? Ive really gotten into audio programming, but the stuff I'm making is currently all over the place (like this message) using different snippets of code and tutorials I've found here and there. Half of the sources are old, so I don't know which path I should be following. Any hints would be appreciated! Earle

22 years, 1 month

Re: [linux-audio-dev] Best road to audio programming happiness?

by Earle Castledine

Wow, thanks a lot everyone. I'm certainly going to check out JACK, but is GTK+ flexible enough (can you make your own buttons and stuff) Actually, don't answer that, that's just laziness on my part - Its just that I've noticed that the graphics sometimes take a back seat in the linux world :) ... Well that uses up my one free "really newbie" question. I promise the next question I post will be thoroughly researched! Thanks again, Earle

22 years, 1 month

[linux-audio-dev] Compiling DJplay

by Frank Barknecht

Hallo, I'm having a strange problem with linmpeg3 while compiling DJplay (http://linux1.t-data.com/djplay/) All goes well until the final linker step which gives this error: g++ -o djplay djplay.o display.o [...] mp3.o [...] recorder.o \ -L$QTDIR/lib -lqt-mt `pkg-config --libs glib jack` -laudiofile -lmad \ -lmpeg3 mp3.o(.text+0x4ac): In function `mpeg3demux_read_char': /usr/include/mpeg3demux.h:104: undefined reference to `mpeg3demux_read_char_packet(mpeg3_demuxer_t*)' mp3.o(.text+0x4e9): In function `mpeg3demux_read_prev_char': /usr/include/mpeg3demux.h:118: undefined reference to `mpeg3demux_read_prev_char_packet(mpeg3_demuxer_t*)' collect2: ld returned 1 exit status make: *** [djplay] Error 1 This is using the Debian testing packages of libmpeg3. I als tried recompiling the library, but it still gives this error. Anone any tips on where to look for the error? ciao -- Frank Barknecht _ ______footils.org__

22 years, 1 month

Re: [linux-audio-dev] LL-patch for SuSE kernel?

by Stefan Nitschke

>yes, suse kernel (since 8.1) already includes most of the >necessary changes. some parts are missing but they are on >the rare code path, which has been not audited quite well, >anyway. Well i do have a LL patch for the original SusE 8.1 kernel that comes with the distribution, including the capability patch. The original SuSE 8.1 kernel does not work well without that patch on my machines. I also have a patch that adds cpufreq and a patch for BIOSes with broken ACPI. That patches are only tested on my Dell i8500, but for me they work perfect. I dont have patches for SuSE 8.2 ... i wait for an update until the first stable 2.6.x kernel based SuSE distro is out. - Stefan _________________________________________________________________ STOP MORE SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail

22 years, 1 month

[linux-audio-dev] mixing algorithms...

by David E. Storey

Hey there... I have an incredibly naive question... How does one mix n channels of audio down to one channel? I've scoured the 'net as best I could and haven't really found anything very authoritative. Suppose I'm dealing with float point data between -1.0 and 1.0 and have n channels. I know physically, it's all a summation of the individual waves, but strictly, summation of multiple waves between -1.0 and 1.0 doesn't keep you between -1.0 and 1.0. Looking through sox, they tend to multiply by some gain value relative to the number of channels. (namely... an average) So is averaging considered a valid professional audio method of digital mixing? what if your source samples are all 16bit? Wouldn't you need to dither in a case like that? Doesn't averaging also imply truncation of your source signal? Am I missing something here? I've tried looking to see what jack and ardour do, but was lefting wondering WHERE to look. respectfully, d!

22 years, 1 month

[linux-audio-dev] M-Audio MobilePre/Sonica/Transit/Ozone testers wanted

by Clemens Ladisch

The M-Audio MobilePre/Sonica/Transit/Ozone devices need a firmware download before they can be used with Linux. I've released a first beta of the madfu-firmware package which tries to accomplish this. Please note that I do not have any of these devices, and that the loader is not tested at all. That's why I'm searching for volunteers. :-) To download the beta, go to http://sourceforge.net/project/showfiles.php?group_id=87777&release_id=1833… Please send any success/failure reports to usb-midi-fw-user(a)lists.sf.net Regards, Clemens

22 years, 1 month

[linux-audio-dev] midi controls API, is it possible?

by antoine rivoire

Hi all, I am working towards using a set of linux audio apps in a live context. With recent development of Jack and apps such as djEQ and such, things look promising. In this light, an idea came to mind. (Keep in mind that I am thinking aloud, and that I am no expert in audio or midi programming). How feasible would it be to implement and a Midi controller API to have a standard, graphical ( a la qJackconnect) application API that Synths and such could use to change midi controllers assignment on the fly or load existing presets? I don't think that the audio framework that has been worked on in linux had live use in mind, but I am convinced that it lends itself to it. In the same context, and this might already be possible, is it possible to have a script calling different apps with patches/presets for each one of those? I am thinking along those lines: during performance: Call script -> opens say Zynaddsubfx with a certain master, Freqtweak with a certain session, Hydrogen with a certain song etc -> call end of piece from script which exits all these apps -> call another script for next piece. Regards Ant- -- antoine rivoire <antoine.rivoire(a)ntlworld.com>

22 years, 1 month

Re: [linux-audio-dev] What's the best audio IO API on Linux

by hexe_2003＠directbox.com

-------- directBOX Reply --------------- From: harold_zhu(a)hotmail.com To : linux-audio-dev(a)music.columbia.edu Date: 15.09.2003 04:13:24 <p>Hi, Folks: <p>I am new here and I am also kind of new to Linux, so I have a basic question. I have worked on a multi-media project on Windows platform, and I used WaveIn and WaveOut functions as audio IO interface to capture and playback real-time audio. Now, I need to do a port to Linux.......so what's the best audio IO API on Linux? <p>In my search so far, I understand that both OSS and ALSA can do the job (real-time audio capture/play).......but what's the difference? Stability wise? Ease-of-use? Performance wise? Also any other candidate, in particular, cross-platform wrapper API? <p>Thanks Express yourself with MSN Messenger 6.0 -- download now! ---- Hi! Well, the main differences between the OSS-Layer and ALSA are: 1.) alsa is the new driver in linux kernel >= 2.6.X 2.) oss-layers need ioctl() - calls to manage/configure sound devices (and ioctl() calls are just possible for root-users !!!!!),so oss is really user-unfriendly if you want to programm a application 3.) alsa is easier to use for midi / pcm capturing/playback 4.) both are less documentated ( I can tell you that !!! :) ) , but alsa has a few basing programming tuts for C ( c++) 5.) alsa is basicly said a "wrapper", a front-end of the oss-arch and it is highly recommended to use alsa at all. I hope this helps, 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

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Linux-audio-dev