Linux-audio-user November 2009

linux-audio-user@lists.linuxaudio.org

160 participants
143 discussions

by Jörn Nettingsmeier

hi *! thanks to contributions from a number of ffado folks) (notably stefan richter, kernel firewire developer, the irq priorities howto in the ffado wiki at http://subversion.ffado.org/wiki/IrqPriorities should be in a usable shape. it's split in two parts: the first one shows how to tweak IRQ priorities manually (because it's useful to know, if a bit tedious), and the second shows how to offload the grunt work to rui's rtirq script. however, the general hairiness of messing with kernel thread priorities on an rt kernel demands some more eyeballs on this. i'd welcome user reports and suggestions/corrections from people with in-depth kernel knowledge. no need to cross-post your contributions (unless you want to discuss them widely), i will collate all suggestions and integrate them into the wiki. of course, if you are willing to take the trouble to sign up on the ffado homepage (http://ffado.org/?q=user/register), you are welcome to work on the wiki directly. this information currently resides on ffado.org, because irq tuning is a hot topic for users of firewire audio devices. however, the plan is to move the relevant information upstream into the kernel rt wiki once it' has seen some more review. i'm not currently on the rt users list - if anyone is, feel free to forward this message. i'd appreciate cc:s to my private address in that case. best, jörn

15 years, 10 months

plugin for RIAA eq?

by Josh Lawrence

Hi all, I'm looking to record some albums into Ardour. I have a hardware phono preamp that does the secret-squirrel RIAA eq stuff, but it's very flaky. Is there a simple insert-it-and-forget-it eq for record players? -- Josh Lawrence http://www.hardbop200.com

15 years, 10 months

Re: [LAU] Fluidsynth, soundfonts, jack, and latency

by Jonathan E. Brickman

Yes, I use the same stress-test method :-) I have seen your symptoms on my setup. I call it "ALSA confusion". This happens as a result of poorly written ALSA plugin code, or hardware which ALSA and/or the kernel does not understand or work with very well. I found the following specific causes listed in WWW references: 1. The ALSA Jack plugin. Don't try to use it. It is bad. I saw this one happen. 2. Very heavy use of my motherboard sound system with ACPI engaged in the kernel. I turned off ACPI in the kernel, my latency dived, performance rose, and ALSA confusion vanished. 3. Sharing an IRQ between the motherboard sound and the video system. This can be tricky to solve, it can require BIOS changes and/or PCI card position changes, and is not always possible for motherboard hardware. Happily, a very good quality PCI implementation should not exhibit this problem at all. I didn't see this one happen (my motherboard is new), but read about it a lot in trying to solve my problems. 4. Attempts to write to the same ALSA device by two different apps simultaneously. On AVLinux this shouldn't be too hard to spot, in many desktop distro situations it might be considerably more difficult. The ALSA docs say the problem doesn't exist because the 'dmix' plugin is automatically engaged, but it's simply not factual, the automatic solution just does not happen in a great many cases, and my new very-low-noise pro audio sound card is one of them. I solved this one by permitting only Jackd to output directly to the ALSA device; everything else outputs either to ALSA's Pulse driver (thus far working very well indeed) or to Pulse (itself designed to handle multiple streams), which then hands the data to Jackd, which is tremendously good at handling multiple streams, at the very low latencies which we need. J.E.B. > Jonathan E. Brickman wrote: >> Guru, do you know what was/is the CPU load during the episode? >> J.E.B. >> > > No, Jonathan, unfortunately I didn't check... was running behind > schedule before the gig, and haven't been near my system since. It may > take a while for me to get back to my system, and checking CPU load > will be the first thing I intend to do. > > Couple of other things that I missed out in previous posts. Firstly, > before the gig I wanted to check whether it was a qsynth-specific or > general fluidsynth issue, so I installed ghostess, which can run > multiple instances simultaneously. I loaded the same soundfonts, and > experienced exactly the same issue - so if there's a bug in the app, > then it must be in the fluidsynth libraries. > > Second issue of note: few weeks ago, while still running Ubuntu, I > wanted to find out what exactly caused the jack crash that I reported > on this list at the time (perhaps unrelated to the current issue) . I > found a "stress test" to replicate the problem: hitting a lot of notes > while keeping my sustain pedal down. Initially, the crash would happen > within 20-30 seconds of banging the controller (!). When I changed the > polyphony settings from 256 to 64, it would be much more stable - for > more than 10-15 mins of banging! Again, I was able to replicate the > same thing with ghostess. > > This incident has left me with a lurking suspicion about a possible > bug in the fluidsynth libraries. I'm curious, though... has anyone > else experienced similar issues? > Looking forward to pointers/feedback/suggestions. > Cheers, > > Guru

15 years, 10 months

qjackctl gets confused when used through ssh -X

by Jörn Nettingsmeier

hi rui, hi *! two hosts connected via netjack. local host uses qjackctl. now ssh -X into remote host, start qjackctl and hope for a forwarded window. no luck. all that happens is that the *local* qjackctl window pops up. this doesn't happen with other gui apps. i use several xosviews on several hosts frequently without problems. any guesses as to what might be going on? best, jörn

15 years, 10 months

Re: [LAU] Fluidsynth, soundfonts, jack, and latency

by Guru Prasad B. R.

Jonathan E. Brickman wrote: > Guru, do you know what was/is the CPU load during the episode? > > J.E.B. > No, Jonathan, unfortunately I didn't check... was running behind schedule before the gig, and haven't been near my system since. It may take a while for me to get back to my system, and checking CPU load will be the first thing I intend to do. Couple of other things that I missed out in previous posts. Firstly, before the gig I wanted to check whether it was a qsynth-specific or general fluidsynth issue, so I installed ghostess, which can run multiple instances simultaneously. I loaded the same soundfonts, and experienced exactly the same issue - so if there's a bug in the app, then it must be in the fluidsynth libraries. Second issue of note: few weeks ago, while still running Ubuntu, I wanted to find out what exactly caused the jack crash that I reported on this list at the time (perhaps unrelated to the current issue) . I found a "stress test" to replicate the problem: hitting a lot of notes while keeping my sustain pedal down. Initially, the crash would happen within 20-30 seconds of banging the controller (!). When I changed the polyphony settings from 256 to 64, it would be much more stable - for more than 10-15 mins of banging! Again, I was able to replicate the same thing with ghostess. This incident has left me with a lurking suspicion about a possible bug in the fluidsynth libraries. I'm curious, though... has anyone else experienced similar issues? Looking forward to pointers/feedback/suggestions. Cheers, Guru

15 years, 10 months

Advice on Multiple Volume Settings

by Kenneth Jacker

I want to ask the "experts" on this mailing list a question I've had for years. It involves "best practices" for the multiple volume settings available on most computer systems ... Say I am playing an audio stream from 'last.fm'. The way I see it, there are *four* different possible volume settings: "line" (e.g., PCM) volume, application (e.g., Rhythmbox, TVTime, ...) volume, mixer "master" volume, and speaker volume. I would guess that the last (speaker) volume should be set (dynamically when needed) to whatever is currently most appropriate for the listener. But what about the other three? Should they all be set at 50%? If not, what other values should be used? Can anyone give some guidelines? Thanks for your comments! -- Prof Kenneth H Jacker khj(a)cs.appstate.edu Computer Science Dept www.cs.appstate.edu/~khj Appalachian State Univ Boone, NC 28608 USA

15 years, 10 months

FYI wineasio 0.7.5

by Joakim Hernberg

Just to let everyone know that I've updated wineasio on http://sourceforge.net/projects/wineasio/ Changes are: Fixed wrongly reported output latency. Changed the SCHED_FIFO priority of the win32 callback thread. * Call jack_client_real_time_priority() to get reccomended priority from JACK * Removed hardcoded SCHED_FIFO priority of 86 * Set win32 callback thread to SCHED_FIFO, priority as requested by JACK Added fork with call to qjackctl from ASIOControlPanel(). Joakim

15 years, 10 months

Re: [LAU] qjackctl gets confused when used through ssh -X

by Patrick Shirkey

On 11/02/2009 12:58 AM, drew Roberts wrote: > On Saturday 31 October 2009 22:53:20 you wrote: > >>> Well, when I run one on my local machine, I want any changed configs to >>> be stored for the local setup. When I run one remotely through an ssh >>> tunnel say, I want any changed configs to be stored for the remote setup. >>> (I think. Does that make sense?) >>> >>> >> I don't see much point of storing a local copy of a ssh tunneled config >> file. If you are tunnelling the config file should be accessed from the >> remote machine. >> > OK, I see I wasn't clear. For the tunnel case, I would want any changes to the > config to be saved on the machine at the remote end of the tunnel, not the > local end. > I was thinking the other way round. Thanks for clarifying. > To my way of thinking, when I run a program on a remote machine down an ssh -X > tunnel, I want to program to run on the far machine and the display to show > up on the local machine. At the same time, This program should behave as if > it is running on the remote machine. At the same time, I want to be able to > run the same program on the local machine. This program should behave as if > it is running on the local machine (that is, normally.) It should not matter > which program I kick off first, the local or the remote. Firefox, for one, > does not behave this way for me and I don't like the fact. > > Can someone explain to me my error if I am thinking in a boneheaded way about > this issue? > > Not boneheaded. The only assumption is that you should be able to run two instances of the same app at the same time on the same machine within the same x session. There are lots of apps that don't allow this. Instead they allow for multiple windows but they are all running of the same instance. In this case qjackctl appears to do neither unless you set the correct settings in the env var or the just added commandline switch. Although according to Fons this behaviour is new and in the past it was not necessary to do either. I guess that firefox doesn't let you start an instance over the tunnel and then open a window on the local desktop too? Cheers. Patrick Shirkey Boost Hardware Ltd

15 years, 10 months

Hydrogen and compiling

by Julien Claassen

Hello drummers! I have two questions, one dependent on the other, so if the first is negative, no need to read on. :-) If I get the hydrogen 0.9.4 source there's a subdir extra, in which I find hydrogenPlayer and hydrogenSynth. Does one of these at least have a text based interface, which I can start, without any Xserver running somewhere? If yes: How can I build it? It doesn't build automatically. I tried by hand using: C++ with some guessed -l-options, with qmake and gmake. Qmake built all the Makefile's, but still some problem there, which in my eyes shouldn't be. thanks for anything at all in advance Julien -------- Music was my first love and it will be my last (John Miles) ======== FIND MY WEB-PROJECT AT: ======== http://ltsb.sourceforge.net the Linux TextBased Studio guide ======= AND MY PERSONAL PAGES AT: ======= http://www.juliencoder.de

15 years, 10 months

DVDs and Ubuntu 9.10

by Bob van der Poel

Hi guys. I know this is a bit off topic, but I'm getting frustrated beyond belief trying to get reasonable results from my DVD drives with a newly installed ubuntu 9.10 The drives are both connected to a PATA interface (the only one on the MB). My hard drives are all SATA. All worked just fine on previous MBs and linux versions. Lastly had Ubuntu 8.04 running. My problem is that I know have very jerky video playback and slow seeks and crashes. I've tried mplayer, totem and vlc. Vcl seems to work best, but it's no star on this system. I've tried uninstalling pulseaudio, but that makes no difference. I've done a lot of reading of similar problems, but nothing seems to vector in on this. The ubuntu forms haven't been much help either ... just a lot of suggestions on trying different players, and installing libcss2, etc. That doesn't seem to be the problem. My guess is that it's a IRQ or DMA problem. I have no idea how to diagnose this or fix. So ... any ideas here???? -- **** Listen to my CD at http://www.mellowood.ca/music/cedars **** Bob van der Poel ** Wynndel, British Columbia, CANADA ** EMAIL: bob(a)mellowood.ca WWW: http://www.mellowood.ca

15 years, 10 months

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Linux-audio-user November 2009