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 -
Saw this announced on the Linux Musicians site, thought it may be of
interest to some folks here. (Sorry if it's a repost).
Instructors are professors Xavier Serra and Julius O. Smith III, two
very well-known DSP worthies.
Course syllabus :
Week 1: Introduction; basic mathematics
Week 2: Discrete Fourier transform
Week 3: Fourier transform properties
Week 4: Short-time Fourier transform
Week 5: Sinusoidal model
Week 6: Harmonic model
Week 7: Sinusoidal plus residual modeling
Week 8: Sound transformations
Week 9: Sound/music description
Week 10: Concluding topics; beyond audio signal processing
Alexander Carot contacted me to spread the news:
Starting in April 2016, three research assistant positions (PhD
candidates welcome) will be available within the Soundjack project. If
interested, please contact Prof. Carôt (a.carot(a)inf.hs-anhalt.de).
(copy-pasted from <http://www.soundjack.eu/jobs.html>)
I've been told one is TV-L13, the other is 75% and the third is 50%
(money equivalent can be found here )
The project will be about making music in a distributed environment,
contract will last three years (no idea if extendible).
Working from home is negotiable and even considered part of the project.
Candidates are expected to speak English, German is explicitly NOT
Feel free to forward to interested parties.
I want to propose the follow flag for raptor in liblrdf library:
#if RAPTOR_VERSION >= 20000
raptor_world_set_flag(world, RAPTOR_WORLD_FLAG_WWW_SKIP_INIT_FINISH, 1);
before raptor_world_open() is called (explicitly or implicitly),
for example after raptor_new_world() in lrdf_init().
That flag avoids to call curl_global_init() (not thread-safe) in
raptor_www_init() and curl_global_cleanup() in raptor_www_finish().
Rare but possible (I'm lucky), if raptor is compiled with curl support,
I have experienced the follow crash during Rosegarden startup:
#0 0x00007ffff0a84f39 in lh_insert () from /lib64/libcrypto.so.1
#1 0x00007ffff0a087ba in OBJ_NAME_add () from /lib64/libcrypto.so.1
#2 0x00007ffff0a94cf8 in OpenSSL_add_all_ciphers () from /lib64/libcrypto.so.1
#3 0x00007ffff0a94cae in OPENSSL_add_all_algorithms_noconf () from /lib64/libcrypto.so.1
#4 0x00007ffff1acf20c in ?? () from /usr/lib64/libcurl.so.4
#5 0x00007ffff1ad605a in curl_global_init () from /usr/lib64/libcurl.so.4
#6 0x00007ffff22cc0fa in raptor_www_init () from /usr/lib64/libraptor2.so.0
#7 0x00007ffff22c9ef0 in raptor_world_open () from /usr/lib64/libraptor2.so.0
#8 0x00007ffff22c63f1 in raptor_new_uri () from /usr/lib64/libraptor2.so.0
#9 0x00007ffff5d26701 in lrdf_read_file_intl () from /usr/lib64/liblrdf.so.2
#10 0x00007ffff5d27626 in lrdf_read_file () from /usr/lib64/liblrdf.so.2
#11 0x00000000004d8d79 in Rosegarden::LADSPAPluginFactory::discoverPlugins() ()
The code is a simple lrdf_init, for-loop of lrdf_read_file, lrdf_cleanup,
and curl seems useless to read/manipulate rdf files for LADSPA plugins.
I have recompiled raptor without curl support
to use libxml, so the only work in raptor_www_init() is to set
world->www_initialized = 1;
without the call for curl_global_init().
Some updates on <http://kokkinizita.linuxaudio.org/linuxaudio/downloads/index.html>
- Added -S option, disables resampling but of course
requires word-clock sync.
- Auto selection of best resampler filter lenght.
- Cleanup and bug fixes.
- Bugfix: will now exit when zombified or when
- Added proper license headers and GPL3 copy.
I also completely replaced the code in Jack1 that
calculates the proper running order of clients.
The previous algorithm failed to do this in some
cases. It could not be 'fixed' easily as it was
basically using the wrong algorithm.
Affected files are
There seems to be no interest from the Jack devs,
but if anybody wants to test this I can either
provide the modified files or a patch against
git commit 5af5815c47630b77cc71c91a460f8aa398017cf7
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
I've run across a phenomena that puzzles me.
It appears that each time I start the jack server on an usb card,
jack_iodelay will report a different "extra loopback latency". I've
seen this phenomena on a behringer x32, and just verified it on a rme
For instance with jack1 at 64/2 on the babyface, I come up with values
of 232,233,234, and 266. With jack2 I saw 231, 233, 248, 318, 335. A
run with jack1 at 2048/3 came up with 2589, 2590, 2633, 2634, and 2667.
I also tested with jack_delay, which also comes up with different
values when I restart the server. Note that on consequent invocations
without restarting the server the values stay the same for the 2
Maybe not a huge problem and I suppose I'll set the latency
compensation somewhere in the middle of the results, but still I'm
curious of the mechanism behind this phenomena.
FWIW, I don't think I've ever seen this on my pci cards, but I'll run
some tests when I get to the hardware and find some extra time.