I just found this list after being directed to the IRC channel over the
weekend. I'm new here! Lately I've been dabbling in a bit of open-source
audio development (I say open-source rather than linux, because I've been
dabbling on both linux and windows).
Anyhow, amongst other things I've been trying to teach myself about DSP, so
I wrote a really (really, really, really) naive distortion plugin. I was
wondering if anyone would be interested in taking a look at it and giving
me some feedback, and tips on where to go next.
I wrote a little about it here:
And the code is at: https://github.com/guysherman/si-plugins
I've got some other projects on the boil that I've been talking about with
the crew from the Ardour list, which I'll mention here when they take shape
a little more.
I am fairly new to USB dev (in linux in particular, but also in general), but I
would very much like to try to get support for the above device working in
- Is this an appropriate place to discuss snd-usb-audio?
- Are there any recommended reading pointers for behavior of the quirk table?
I patched parse_audio_format_rates_v2(), get_sample_rate_v2(), and
set_sample_rate_v2(), and through some sort of beginner luck was able to get
aplay audio out of the first two channels. That was incomplete hackery though
(eg fixed sample rate), and I would like to learn how to properly add quirk
support. There have been other reports that this device worked OOTB, but I
fail to see how!
I've also been examining the traffic to the device with wireshark and a
win7 vm, but the learning curve for USB is a bit steep, so I am digesting. (:
If anyone can provide suggestions on lsusb output alone, here's what I have:
[x-post from alsa-devel due to empty thread -
This is my first post here. I’m note new to audio programming or linux, but I haven’t done much in terms of combining the two. Most of my audio programming has been on os x.
Currently working on some realtime convolution with lots of channels and low latency requirements, but I am running into some unexpected cpu-spikes and hope some of you might have an idea of possible causes.
I’m processing 32 sample-blocks at 48KHz but roughly every 0,6 seconds I get a large spike in cpu usage. This cannot possibly be explained by my algorithm, because the load should be pretty stable.
I am measuring cpu load by getting the time with clock_gettime(CLOCK_MONOTONIC_RAW, timespec*) at the beginning and end of each callback. When converted to a percentage my cpu load hovers somewhere between 40 an 50% most of the time, but more or less every 900 callbacks (0.8 seconds there is a spike of more than 100%.
I am not doing any IO, mallocing or anything else that could block. My threads are SCHED_FIFO with max priority (I have 4 threads on 4 cores).
The only explanation I can come up with is that my threads are somehow pre-empted even though there are realtime threads. Is that even possible? And is there a way to check this? Besides pre-emption maybe my caches are severely thrashed but i find that unlikely as it seems to happen on all 4 cores simultaneously.
I’m running (more or less default install, no additional services run-in) Linux Mint 17.3 with a 3.19.0-42-lowlatency kernel on a core i7-6700 with hyperthreading/turbo disabled.
I remember reading somewhere that realtime threads cannot run more than .95s every second. That would be very bad if it actually meant my threads are blocked run for a period of 50ms straight…
Anyone have any thoughts on possible causes?
Qtractor 0.7.4 (the tackiest gluon) has been released!
Y'all know the drill...
Qtractor  is an audio/MIDI multi-track sequencer application
written in C++ with the Qt framework . Target platform is Linux,
where the Jack Audio Connection Kit (JACK ) for audio and the
Advanced Linux Sound Architecture (ALSA ) for MIDI are the main
infrastructures to evolve as a fairly-featured Linux desktop audio
workstation GUI, specially dedicated to the personal home-studio.
Change-log (since last release):
- Eye-candy warning: muted/non-soloed tracks are now shaded over the
- Faster and crispier VST plugin editor (GUI) idle cycles.
- Fixed all core processing when any plugin has more audio outputs than
channels on a track/bus where it's inserted.
- Added one decimal digit to all percentage input spin-boxes on the MIDI
- Added brand new and global option to disable the so called "catch-up"
default behavior (cf. View/Controllers.../Sync).
- Fixed some track control issues related to MIDI Controllers generic
mapping (cf. View/Controllers...).
- Try making Help/Shortcuts... dialog window modeless, as far as under
MIDI Controller, Inputs/Outputs Connections window also gets accessible
- Fixed some vertical scrolling and play-head line re-drawing glitches
introduced by the recent unlimited slack to editing beyond current
contents length on main tracks view.
- Added one decimal digit to the Pitch-shift spin-box on audio
Clip/Edit... properties dialog window.
- Added application keywords to freedesktop.org's AppData.
- Fixed local keyboard shortcuts on the Files organizer widget actions
- Improved Mixer multi-row layout (patch by Holger Marzen aka. bluebell,
- Fixed the Ctrl+drag/cloning left of a clip when towards near the
beginning of session.
- source tarball:
- source package (openSUSE Tumbleweed):
- binary packages (openSUSE Tumbleweed):
- wiki (on going, help still wanted!):
Weblog (on going, upstream support):
Qtractor  is free, open-source Linux Audio  software,
distributed under the terms of the GNU General Public License (GPL )
version 2 or later.
 Qtractor - An audio/MIDI multi-track sequencer
 Qt framework, C++ class library and tools for
cross-platform application and UI development
 JACK Audio Connection Kit
 ALSA, Advanced Linux Sound Architecture
 Linux Audio consortium of libre software for audio-related work
 GPL - GNU General Public License
Enjoy && Have (lots of) fun ;)
rncbc aka. Rui Nuno Capela
The migration should be now complete. Please let us know if you
encounter any problems.
On 1/26/2016 11:12 PM, Ivica Ico Bukvic wrote:
> As some of you may be already aware, this past December I was notified
> our current virtual server that hosts a broad array of outreach
> services, including these mailing lists, will be decommissioned at the
> end of this month. Since, I've been working on securing the
> infrastructure and ongoing support onto a brand new physical blade. I
> am pleased to report we are at the very end of what has proven to be a
> fairly intense journey (needless to mention I learned a lot more than
> I ever wanted to about sysadmin). Our new setup is considerably more
> powerful and I am confident it will offer a significant improvement in
> performance over the old one. As we enter the final stage in the
> porting process, there will be a brief downtime tentatively scheduled
> for 11am Eastern Time (East US Coast) tomorrow, Wednesday, January
> 27th. During this time, you will experience inability to access hosted
> services, including web and mailing lists. My intent is to have the
> transition complete as quickly as we can do the final rsync and IP
> address reconfiguration. I will let you know as soon as we've
> completed this final step. Thank you for your support and understanding.
As some of you may be already aware, this past December I was notified
our current virtual server that hosts a broad array of outreach
services, including these mailing lists, will be decommissioned at the
end of this month. Since, I've been working on securing the
infrastructure and ongoing support onto a brand new physical blade. I am
pleased to report we are at the very end of what has proven to be a
fairly intense journey (needless to mention I learned a lot more than I
ever wanted to about sysadmin). Our new setup is considerably more
powerful and I am confident it will offer a significant improvement in
performance over the old one. As we enter the final stage in the porting
process, there will be a brief downtime tentatively scheduled for 11am
Eastern Time (East US Coast) tomorrow, Wednesday, January 27th. During
this time, you will experience inability to access hosted services,
including web and mailing lists. My intent is to have the transition
complete as quickly as we can do the final rsync and IP address
reconfiguration. I will let you know as soon as we've completed this
final step. Thank you for your support and understanding.
Ivica Ico Bukvic, D.M.A.
Creative Technologies in Music
ICAT Senior Fellow
Director -- DISIS, L2Ork
School of Performing Arts – 0141
Blacksburg, VA 24061
Is anyone here using ccmake version 3.4.1?
I've had a couple of people saying it segfaults when going through its setup.
I'm using V 3.0.2 and not seeing any problems at all.
Will J Godfrey
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.