Hi :)
*Clarification from the viewpoint of a user*
For me, as a user only, there are some "reasons", resp. "fears" why I
never tested LADI:
I don't know what exactly it can handle. Which apps can be handled by
LADI? What needs to be set up for the apps? In other words, will it
really handle a session or just some points of a session? I once tested
LASH and it wasn't able to handle anything I need. Without much
knowledge about writing shell scripts, I'm able to launch wanted apps
and restore connections, not the perfect way I would like to have, e.g.
because I still need to place the windows, but without trouble, while
e.g LASH does not do this this job, maybe because I missed to google for
hours to learn the basics about LASH.
Are there packages or do I have to compile it by solving a dependency hell?
How will it handle a session when some audio apps tend to crash on my
machine? Will this cause trouble for LADI? Is LADI some kind of program
that will run during the session or will it just run similar to a shell
script just to launch and restore a set up, resp. just when saving a set
up? When using a session handler, will it be possible that an app that
normally is stable, become unstable?
A shell script isn't a session handler, but anyway it can restore a lot
and that without any requirements, limitations, because of apps that are
not compiled to be fine with LASH, LADI or what session handler ever.
*Willing to test it*
I'm willing to give LADI a chance and try to add it to my 64 Studio
3.0-beta3 x86_64 and openSUSE 11.2 x86_64.
I'm willing to spend some hours to google and read about LADI.
*But*
I'm not willing to troubleshoot any problems, if it would make handling
my sessions more difficult, than it would be without "a", resp. "this"
session handler.
I guess I can try to add LADI this week to my Linux installs :).
Cheers,
Ralf
>
> [LAD] LADI
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>
> From: Nedko Arnaudov <nedko@email-addr-hidden
> <mailto:nedko@email-addr-hidden?subject=Re:%20%5BLAD%5D%20LADI&replyto=87aayhdkbr.fsf@usbix.spacelabs.org>>
>
> Date: Fri Nov 20 2009 - 22:15:20 EET
>
> After recent discussion on IRC I'm loosing faith in whether it is worth
> to contribute to linux audio session handling/management. Two reasons
> were given why it does not get testing from users. One is that what I
> did so far is not mature, has annoying bugs and I'm not wanting to fix
> them. The other one is that ladish is not giving more than users already
> have with qjackctl. Also it was mentioned that D-Bus is not what users
> find acceptable for controlling jack server.
>
> Given the almost missing feedback about LADI development from community
> members that could benefit from it, I'm not sure whether I should
> continue to contribute. Maybe I should give up on trying to make linux
> audio usable for my needs. I could also stop using computers and make
> music only by using my guitar. Because alternatives to Linux Audio
> (windows/mac) don't suit my needs. Moreover they don't have the
> potential to suit. This is why I'm contributing to Linux Audio and not
> making VST plugins or something. This anti-dbus movement is getting too
> far. If there is no user that accepts my point of view, there is no point
> of me contributing.
>
> Because it may be possible that someone has missed the whole point of my
> jackdbus and session handling effort, I'll try to explain what I find
> wrong/unacceptable in JACK (dbus-less) system as we have it now.
>
> * JACK server tries to kill clients that are suspected to misbehave and
> cause xruns or expose other kind of bad behaviour. This can result in
> qjackctl (or patchage for example) being killed. IMO, killing control
> apps is wrong. Apps that that don't process audio/midi should be
> treated differently.
> * When jackd is autolaunched, log messages are going to stdout/stderr of
> the app that launched them. This is wrong, unix daemons are supposed
> to have a log file, even if they are per-user. One of the reasons why
> log file is a good thing to have is that it allows to analyze problem
> post factum. This helps a lot if some misbehaviour is rarely
> reproducable.
> * Control apps that start the jack server through jackd know only about
> the parameters that were known at compile time. Somewhat recent
> example, IIRC, jack2 specific parameters (-S) and firewire options
> missing after upgrade of jack because qjackctl does not know about
> them. IMO, control apps should be able to query parameters for jack
> and display the available options to user.
> * Control apps that manage jack connections, are subject to realtime
> constraints. IMO, this complicates control apps development for no
> good reason. This is valid only for jack1. jack2 already uses
> non-realtime threads for port notifications.
> * Implementing control app requires C level program or use of specially
> crafted bindings. It will be good if control apps could be
> implemented with few lines of code in a scripting language as Python,
> Ruby, Perl, etc.
> * JACK graph (clients, ports and connections) API is badly designed and
> is prone to race conditions. Fons talked about this problem recently
> too.
> * Session handling capabilities are suboptimal. Various programs lurk
> here. I'll mention the two most popular ones: qjackctl cant
> save/restore internal state of the programs. It also cant save and
> then relaunch them automatically. lash cannot manage jack
> settings and cannot restore connections for applications that are not
> linked against liblash. There are other problems but those are the
> most
> frustrating ones.
> * Hardware port virtualization is suboptimal. it is provided through
> the JACK "system" client. The only reliable ports are first ones, they
> are expected to be the main input/output. If applications wants to
> connect to phones for example it does not know on what ports they
> are. projects/session should be movable to other system, one with
> different hardware setup and [extensive] reconnecting should not be
> required.
> * Hardware port names are not human readble. Aliases exist but are not
> widely used for various reasons. Users should be able to name and
> group their ports to match their hardware cable setup.
> * JACK "system" client is used for non-hardware ports (-X seq).
> * There is no global list of JACK enabled applications.
> * JACK MIDI is not widely accepted. JACK AUDIO + ALSA seq appears to be
> acceptable solution. IMO, sample accurate audio+midi is very
> important.
> * There is no session handling for netjack LAN setups.
> * Session handling apps cannot restore apps to more than one X11
> screen (do
> not mix with X11 display).
> * Patchage-like (flowcanvas based) patchbay interface is best what I've
> seen. Unfortunately Patchage does not integrate well with other parts
> of JACK infrastructure.
>
> As you can see, I have collected enough problems to fight. Almost all of
> these fixes need new software modules to be written or existing ones to
> be rewritten. In past years I've tried to collaborate
> with people behind JACK, LASH, Patchage and Qjackctl. At the end, I
> think that this attempt was probably wrong, with the only excepton of
> jack2 (Stephane Letz) who accepted my jackdbus development into jack2
> and we worked toghether on improving it and on the more general
> "control API" initiative. The jackdbus code, my first contribution, that
> is supposed to improve this mess was rejected by Paul Davis whom
> maintains jack1. I've got some patches accepted by Patchage`s
> author and maintainer, Dave Robillard, but they were rather cosmetic
> ones. This forced me to maintain a software branch (Dave calls it a
> fork) called lpatchage. It was supposed to be dashboard for the JACK
> system. I also actively participated in lash-0.6.x development. The only
> other developper, Juuso Alasuutari, shared some of my ideas, but at the
> end we ended with fundamental differences about how session handling
> should behave and what lash should become.
>
> As part of my LADI efforts, two people where very helpful. Marc-Olivier
> Barre and I managed to create pyjackctl, later renamed to laditools. It
> is set of minimalistic but very useful control apps for JACK, a2jmidid
> and LASH/ladish. Krzysztof Foltman helped a lot with probably the most
> complex app in the laditools suite, ladiconf.
>
> I'd like to mention people with whom collaboration, even if attempted by
> me was non-existing: Rui Nuno Capela and Bob Ham. They clearly declared
> From start that wont help for various reasons and I appreciate
> this. Because this saved my precious time of part-time contributor to
> Linux Audio.
>
> In May/June this year, Fons Andriaensen got hit by a forcibly packaged
> jackdbus (i'd call it mispackaging of jack) and started a flame war
> against D-Bus evilness. I tried to be constructive until I got message
> From the packager that dbus was forced, even given that he earlier
> stated that he explicitly enabled dbus support in that package for one
> reason or another.
>
> In June this year, it become evident that I'm not able to contribute to
> LASH anymore and that I want something else. I left the LASH project and
> started a new session manager, ladish (project page is at ladish.org).
> The first preview was released not long after. It was not yet a real
> session manager but it was able to save and restore multiple jack
> configs, a foundation for what I call "studio" in ladish. Since then
> I've implemented some more stuff and I was hoping that next preview that
> will be able to relaunch applications and restore connections between
> their jack ports will be ready by the end of this year.
>
> In recent few months, I had less time to contribute to ladish and
> development slowed. The anti-dbus statements from various people
> continued almost always without real argumentation behind them. For
> these that were complains about dbus problems in real setups, I've given
> suggestions. Almost always I got ignorace and more anti-dbus statements
> in return. Maybe what I did is really unusable by others, despite
> it being obviously usable by me. Maybe I suck at trying to help & support
> people who seem to think that ladi is not that bad. Or maybe D-Bus
> is indeed evil and eats babies and I fail to understand why, even after
> I've listen to so many "arguments". Or maybe there are happy people
> using jackdbus and laditools (or even lash-0.6.x) and looking toward
> ladish. But I dont see them. If community does not share my frustration
> with problems of the JACK system I mentioned above and does not accept
> my vision that D-Bus is just the most suitable (but not perfect)
> technology for what I'm trying to achieve, then it would be better for
> everybody if I don't contribute anymore. I can detach from the community
> and I can even detach from linux and even computers.
>
> So now is the time to give your positive feedback and constructive
> critics. Don't troll and don't start another flame war unless your goal
> is to alienate me to stage of me detaching from this community. I will
> not respond to trolish and flamish mails, feel free to contact me
> with private mails if you prefer so. As I'm cross posting this mail, if
> you are subscribed to more than one of the mailing lists, please reply
> only to one of them. In order of preference, lad, lau, jack-devel. This
> should avoid discussions half-shared between lists. If they happen at
> all.
>
> This mail is not supposed to be offensive to anyone. If someone feels
> so, I declare that offense is not intentional. I don't deny the right of
> different opinion on any subject and thus I have no reason to burn
> witches.
>
> --
> Nedko Arnaudov <GnuPG KeyID: DE1716B0>
>
>
>
> _______________________________________________
> Linux-audio-dev mailing list
> Linux-audio-dev@email-addr-hidden
> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
hi...
on a side note to the LADI discussion, which might even be my fault,
i want to tell you what i am currently up to.
in my opinion the inherent fail of session handler stuff, is that
somehow it wasnt easy enough or too complex to integrate lash support
into apps.
also many people didnt like to use some other ipc mechanism...
so to me the most natural way to do session notification was adding it
to jack. most apps are already listening for some jack callbacks.
(at least they should be listening for shutdown :)
so in my working copy of jack1 i have added 2 API calls:
typedef char *(*JackSessionCallback)(jack_session_event_t code, const char* session_dir, const char* prefix, void *arg);
int jack_set_session_callback(jack_client_t *client,
JackSessionCallback session_save_callback,
void *arg);
struct session_command * jack_session_notify (jack_client_t* client, jack_session_event_t code, const char *path );
by calling jack_session_notify() the session callbacks of the listening
clients are invoked.
they are supposed to save their state, and return a string which
specifies, how they want to be restarted. the prefix parameter is unique
and there is a method to make this persistent over session reload.
the aggregation of the returned strings and unique ids is returned by
the notify call.
i have also changed jack_client_open which is able to accept a client
specified unique id. (this must be used when reloading state, so that
clients can be found again
so... a potential session handler is still required. and it needs to be
able to query the portconnections.
in order to restore them.
but clients are not required to have an extra dependency in order to
support sessions.
you may have noticed that this is currently ignoring alsa connections.
but i think we only need to add a way to publish an alsa seq id
via this protocol.
then a pure alsa client would also need to link to libjack and create a
jackclient with no ports and no process callback, in order to
participate in session handling.
i dont see a difference. it just links to "some" session handler lib.
the only disadvantage i am seeing currently is that apps are treating
jack like an abstract audio output, and getting a jack signal up to the
gui layers where the invokation of save is generally happening is a bit
cumbersome.
so far i have only patched oom and ardour. and ardour doesnt quit yet,
when requested.
well... tell me what you think :)
--
torben Hohn
Hey,
Also liking the simplicity, and I think it might be a nice feature to keep
the possiblity to save:
* the studio
* the room
* the project
Perhaps the user could "tagg" each app as what function it has/what its
being used for,
and then allow the saving of all apps with the same "tagg" to a file, for
re-use?
EG:
-name- -tag-
Qsynth piano
JackRack piano (well, its reverb really)
calf piano ( compressor)
and then save tagg piano, and you can reload the same programs?
It does substantially add to complexity I'm aware, but I like the concept of
being able to save subsets of programs and reload them seperatly from the
exact project that they were created in.
It seems a really usefuly feature, get a brilliant piano sound, double click
the file, and your done & playing!
Thats looking from a users point of view. I appreciate that including these
features in JACK might not be the way to go, as its not "core" jack
functionality.
Thought I'd share this idea.. Cheers -Harry
How come the linuxaudio.org mirror (http://download.linuxaudio.org) is not
any more updated with newer releases? Last version available on there is
7.04 which is truly enchant.
What do we need to do to jumpstart this thing again? I presume this would be
something you guys would want to explore, particularly considering that the
hosting/bandwidth are effectively free...
Ico
I wrote a scripting engine for a pro audio plugin by embedding a
CPython interpreter. Since audio sequencing hosts use separate threads
for each audio track, loading more than one instance of my plugin
while running scripting code causes contention on Python's GIl and
results in CPU spikes at low latencies.
While CPython is more than capable of running fast enough in the audio
thread for control-rate (MIDI) work, the GIL is killing us. Using
process migration to move calls to CPython to daemon processes would
take less code than forking python itself, but the scripting engine
includes a python extension module that exposes pointers to the C++
classes in the audio engine. This complicates things quite a bit. The
calls look like this:
size = engine.getAudioBufferSize()
engine.loadPatchFile(SOME_PATH)
instrument.loadAudioFile(SOME_PATH_2)
instrument.setVolume(.5)
...where 'engine' and 'instrument' are C++ classes in the audio engine
that I wrapped in a python extension.
I think that the biggest problem for me is tackling the complexity of
managing new real time daemon processes for each audio track, finding
an IPC method, and also implementing a middle-ware layer that would
allow those synchronous calls to the engine be made back to the host.
This is the sort of overhead that one can expect when trying to use
process migration to work around the GIL. I consider myself an
experienced coder, but just thinking about finding a clean, rock-solid
daemon management and IPC mechanism that works on Mac and Windows
freaks me out.
Does anyone have any comments on this topic?
cheers,
-P
Hi all,
does anyone knows about any Python module for reading incoming MTC
messages? Couldn't find it with a quick google search.
It is not complex to implement, and there are snippets of C code around,
but I'd rather like to not reinvent the wheel.
Thanks,
--
--------------------------------------------------
Pau ArumÃ
Barcelona Media - Innovation Centre
Av. Diagonal 177, planta 9, 08018 Barcelona, Spain
Phone: +34 93 238 1400
How to edit those pages with content links as :
{{topic>midi_software}}
??
Is that for choosen developers only ?
Maybe related information should be added to
editor_notes (http://wiki.linuxaudio.org/wiki/editor_notes).
Thanks
--
E.R.
Random thought spurred by the "feeds are good" tangent of the LV2
discussion:
It would be really nice to have a Planet LAD (like e.g. Planet Gnome
http://planet.gnome.org/ ). Having these things in your RSS reader
makes it really easy to keep up on what people are up to in general.
I don't know how many blog, but having such a thing would probably be an
incentive to actually do so. Anyone adminney at linuxaudio.org
interested in setting up such a thing? It seems like a straightforward
install assuming Python is available.
Cheers,
-dr
Hey guys,
I've been doing some reading around the internet about Object Orierientated
Program designing,
got a OOP design
book<http://books.google.ie/books?id=KpJQAAAAMAAJ&q=object+oriented+software+des…>,
yet still I'm confused on how to approach designing a "large" program.
That's the background to this question: Is mutex locking the only way to
ensure that variables are only
being accessed by one thread at a time? Is it the "right" way to go about
it?
I've seen quite some strong opinions around the internet on how RT threading
should be done,
however I still am not fully sure if PosixThreads is the way to go, (due to
windows not supporting it).
I've googled for "c++ cross-platform threading" which returned this
post<http://www.codeproject.com/KB/threads/thread_class.aspx>.
I've not yet fully understood it,
but I'm also slightly afraid that Ill be learning a bad habit rather than
how to use a good threading lib!
Any advice on where to start? Cheers, -Harry
