Hello,
together with the latest release of MCP/REV/VCO-Plugins by Fons Adriaensen,
AlsaModularSynth-1.7.1 can be considered as a major step forward in realistic
virtual analogue modular synthesis. There are some new sound examples (.ogg)
on alsamodular.sourceforge.net that give an impression of this.
For a detailed list of what is new, check out the "News" section on the
project page.
Have fun !
Matthias
--
Dr. Matthias Nagorni
SuSE Linux AG
Maxfeldstr. 5 phone: +49 911 74053375
D - 90409 Nuernberg fax : +49 911 74053483
Hi all.
I've been trolling and testing various sync methods and I've noticed some
questions popping up. Is it just me or is the linux audio situation a bit
incomplete at this point with regard to information on that subject?
It may just be that most of the programs are still struggling to develope
sync techniques (MTC, MMC, ADAT sync, SMPTE, jack transport, etc. etc.), but
also is there a relative lack of info/tutorials/etc?
The reason I ask, is because not only for my sake, but for the sake of the
community, I'd sure be glad to try and make a dent in that, maybe document
some toots, or whatnot. of course, this all has to be in sync (no pun
intended ;) ) with the development of the capabilities...
I wish I had time to sort of type out something more detailed - I'll get to
that sometime here (running short on time right this minute :) )
one basic hole I see at least in my understanding, is what the HECK is
jack_transport, how does it fit in, etc.? that's ONE - there are lots of
holes for me *laugh* another curious one is ecasound? it's the veteren
around here in a lot of ways - does it sync to anything?
ok well I'll wait for thoughts and then as soon as I can get a chance, I'll
write something longer and sort of put out to y'all what I've found out, and
see what holes can be filled - cheers (sorry for any unclarity in this
email, unclarity is why I'm starting this thread! :) )
- Aaron
www.nquit.com
Hello.
Anyone would like to develop cdparanoia further?
I ripped a CD two times with the following results:
(== PROGRESS == [ !-------| 159332 00 ] == :^D * ==)
(== PROGRESS == [ + + + | 159332 00 ] == :^D * ==)
The errors are explaned this way:
- Jitter correction required
+ Unreported loss of streaming/other error in read
! Errors are getting through stage 1 but corrected in stage2
Which error is more severe: "+" or "!"?
Is "+" corrected properly?
The problem is that the channels of other ripping are swapped at the
point where "!" is located (but "!" may not have caused it). I don't
know which one of the rippings is incorrect (they both could be
incorrect). The channels also have one sample offset after the
swap.
The second ripping has "+" before the "!" point, but both rippings
are indentical up to the "!" point. Would that mean that "+" is
a harmless error and that thus the second ripping is correct? And
that we should rewrite only the algorithm handling the "!" errors?
In addition to rewriting "!" handling (or "+" handling if that caused
the channel swap), I would like get out a printed list of errors.
The error list could then be used in an audio editor for marking
the errors with red color (say).
Also an audiofile comparer program would be great to have: a program
which finds matching regions. Now it was easy to compare the regions
up to the "!" point with md5sum program, but it was difficult to compare
the end part due misaligning. I compared them visually at a few random
points. In such a comparer program each matching sample would match
bitwise for this application, but they could match with an error tolerance
if the application is to compare an original audio and an edited audio
which is affected by dither noise (say). So, such a comparer would
reveal what edits were done in an audio editor -- I have needed such
a program a few times earlier.
Regards,
Juhana
Hi All,
I'm still new to LAD so sorry if this has been asked before - is there
anywhere online that has an introductory tutorial to creating custom
pixmap sliders? I'm looking for a tutorial similar to the gtk dial
tutorial on the gtk.org site. If anyone has a link or info I'd
appreciate it.
Cheers,
Adam
Hello,
I am looking for a deconvolver, that is able to produce impulse
responses from sinus sweeps (and especially the exponentially
sweeping sine wave introduced by Farina).
Do you have any suggestions or at least tips to start an
implementation by myself?
Recently I managed to use the mls tools from nwfiir to produce
an IR of my microverb.
I had to learn the hard way, that simple soundcards are not able
to be used as MLS source because of the non linearities. Even a
simple DA-AD loop gives a result wave that mls2imp cannot cope
with. But an empty loop with an US-122 (unfortunately not with
linux for now) gives something very near to a dirac impulse!
The hunt for the linux convolution reverb has started ;-)
Uwe
--
voiceINTERconnect www.voiceinterconnect.de
... smart speech applications from germany
Daniel asked for this to be forwarded...
--
Patrick Shirkey - Boost Hardware Ltd.
Http://www.boosthardware.comHttp://www.djcj.org - The Linux Audio Users guide
========================================
{This is a draft of a note for the GTK developers, requesting them
to soften their position on disallowing setgid. Please post
comments and suggestions. It carries more weight coming from a
group of us. Also, please tell me where this is should go.}
{The note seems overly long. Suggestions for things to leave out?
Perhaps I should post some of this on the web as a white paper, and
send them a much shorter message pointing to it.}
Rationale
=========
A number of us in the Linux Audio Developers community[1] are trying
to come up with practical ways of dealing with the security exposures
inherent in realtime audio. Our problem is that many audio
applications require realtime scheduling and memory locking privileges
to achieve stable, low-latency performance.
While not a direct threat to system integrity, these privileges easily
allow anyone with a local login to accidentally or intentionally
freeze the machine. In security jargon, this is known as "Denial of
Service". For a dedicated Digital Audio Workstation system, the risk
is generally acceptable. But, we want to do our best to minimize its
effects.
Historically, many Linux audio applications required users to login as
root when needing realtime privileges. Large audio programs often
include complex graphical user interfaces, digital signal processing,
and multi-threaded buffer handling. Running all this as root leaves
the system wide open to devastating security attacks. This is what we
want to avoid.
Solutions Considered
====================
Some packages, like the JACK Audio Connection Kit[2], have
successfully used Linux kernel capabilities[3] to run realtime audio
applications using an ordinary user ID with only the necessary
permissions delegated. Unfortunately, the Linux kernel developers do
not fully support this, because that mechanism currently has known
security holes[4]. Consequently, kernels are shipped with it partly
disabled. The 2.4 kernel requires users to make a two-line patch,
then recompile and reinstall to enable this feature.
As these problems are not likely to be resolved any time soon, we have
been investigating other solutions. The 2.6 kernels provide a new
Linux Security Module (LSM) mechanism[5]. With that, we can turn on
capabilities without forcing all our users to patch their kernels.
But, the security exposure in the capabilities mechanism remains.
So, we are working on an experimental LSM for 2.6 that grants realtime
privileges to applications based on several optional criteria[6]. The
most secure option only grants realtime access to programs or users
belonging to a specific group ID, such as `realtime' or `audio'.
Ideally, our applications would be setgid to that group, so only
realtime programs would gain access to these privileges.
Problems with GTK
=================
Unfortunately, audio applications using GTK cannot take full advantage
of this option, because GTK refuses to run setgid. The unintended
consequence of that policy is to *increase* our security exposure by
forcing us to grant realtime privileges to all the programs of users
who need them, when we would prefer to restrict access to just the
audio programs, themselves.
We have read with interest the rationale[7] given by Owen Taylor of
the GTK development team for disallowing the use of setuid and setgid
in GTK applications.
Owen writes:
In the opinion of the GTK+ team, the only correct way to write a
setuid program with a graphical user interface is to have a setuid
backend that communicates with the non-setuid graphical user
interface via a mechanism such as a pipe and that considers the
input it receives to be untrusted.
This is a fine suggestion, and certainly one viable approach. But, it
seems presumptuous to claim that it is the "only correct way". One
cannot force the many existing Linux audio applications to be
rewritten to follow this advice, and it is unclear that there is any
good reason to do so. Since GUI threads generally use non-privileged
scheduling, in practice realtime priority is restricted to the I/O and
signal processing threads anyway.
Requested Change
================
While sympathetic with the concerns and intentions expressed in Owen's
document, we are not happy with the actual implementation. We want
gtk_init() to stop checking that the group ID equals the effective
group ID. If you really feel that some such test is necessary, then
please disallow operation only when the effective gid is zero (`root'
or `wheel' in most systems).
Note that testing for specific user and group privileges does not
conform to current POSIX thinking on the subject. The standard has
adopted the term "appropriate privileges"[8] for describing the
effects of the implementation-defined security mechanism. This was
done to encourage adoption of more granular privilege implementations
than the traditional monolithic Unix superuser approach. So, no
matter what tests you make, on some modern systems you will not be
able to detect when GTK is running in a privileged context.
System security is evolving in directions that are outside the scope
of GTK and cannot adequately be enforced by any user-level library.
Despite good intentions, incomplete security checking tends only to
make matters worse.
Regards,
--
Jack O'Quin
Austin, Texas
[1] mailto:linux-audio-dev@music.columbia.edu
[2] http://jackit.sourceforge.net
[3] http://ftp.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.4/capfaq…
[4] http://archives.neohapsis.com/archives/sendmail/2000-q2/0002.html
[5] http://lsm.immunix.org
[6] http://www.joq.us/realtime/README
[7] http://www.gtk.org/setuid.html
[8] http://www.opengroup.org/onlinepubs/007904975/xrat/xbd_chap03.html
Hi all,
the following announcement gets sent to all of linux-audio-dev,
linux-audio-user and linux-audio-announce mailing lists in order to
reach as many interested parties as possible; I'm sorry if you
receive this twice or even more often.
I would be glad if we get a lot of participation from your side!
Frank
-----------------------------------------------------------------------
>From April 29th to May 2nd, 2004, the Institute for Music and Acoustics
of ZKM Karlsruhe, Germany, will host the 2nd conference of the
Linux Audio Developers (LAD). As a new feature there will be
presentations of music in addition to technical talks. For this, we
are looking for music that has been produced completely or mostly
under Linux.
We are looking for:
* Interesting demos of sound synthesis, sound processing, etc.
* "Classical" computer music compositions, to be played in a concert
setting
* Pieces from areas such as Electronica, Chill-Out, Ambient etc.
If you would like to participate, please send your composition(s)
to this address:
Linux Sound Night
ZKM, Institut fuer Musik und Akustik
Lorenzstr. 19
D-76135 Karlsruhe
Germany
Please make use of one of the following media formats:
- Audio-CD, DVD or CD-ROM
Possible audio file formats: aiff or wav; mono, stereo or multi-channel;
44.1 or 48 kHz; 16 or 24 bit resolution.
Please include the following items with your submission (in English):
* A short commentary on the compositions
* A short Curriculum Vitae
* A completed and signed printout of the form available here:
http://www.zkm.de/lad
Deadline for submissions is February 29th, 2004.
A jury will select the compositions that will be performed/played.
The jury will award 3 grants to participants to contribute to their
travel
expenses.
Terms and conditions for participation can be found in the form above.
Up-to-date information about the conference is available here:
http://www.zkm.de/lad
--
Frank Neumann (Frank.Neumann(a)st.com), VIONA Development Center
STMicroelectronics, Karlstraße 27, 76133 Karlsruhe