3 Oct
2009
3 Oct
'09
11:08 a.m.
Hi,
I'm looking into doing some real time MIDI programming with either C++
or Common lisp.
I would specifically not schedule anything but deliver everything as
"play it right now" notes.
Is it necessary to use realtime scheduling the way JACK does?
Or is it ok to use normal "user mode" programs?
Your expert advice much appreciated!
Carlo
3 Oct
3 Oct
12:06 p.m.
Hey,
I'd advise C++ & RtMidi if you've done any OOP before, I started out with
that combination,
there are some good examples on the RtMidi
webpage<http://www.music.mcgill.ca/%7Egary/rtmidi/>
.
It provides a MIDI interface on all of Linux-Mac-PC, so its cross-platform.
And I'd advise you to start with "normal" scheduling (I've never coded
an RT
app, but MIDI apps works
100% realtime for me without any upgrading of priority).
Good luck, -Harry
On Sat, Oct 3, 2009 at 2:07 PM, Carlo Capocasa <theman(a)carlocapocasa.com>wrote;wrote:
Hi,
I'm looking into doing some real time MIDI programming with either C++
or Common lisp.
I would specifically not schedule anything but deliver everything as
"play it right now" notes.
Is it necessary to use realtime scheduling the way JACK does?
Or is it ok to use normal "user mode" programs?
Your expert advice much appreciated!
Carlo
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4:06 p.m.
As an alternative, you can use PortMIDI. It's a fairly simple API and
I would recommend it.
Victor
----- Origina
Victorl Message -----
From: Harry Van Haaren
To: Carlo Capocasa ; linux-audio-dev(a)lists.linuxaudio.org
Sent: Saturday, October 03, 2009 3:06 PM
Subject: Re: [LAD] Realtime MIDI programming?
Hey,
I'd advise C++ & RtMidi if you've done any OOP before, I started out with
that combination,
there are some good examples on the RtMidi webpage.
It provides a MIDI interface on all of Linux-Mac-PC, so its cross-platform.
And I'd advise you to start with "normal" scheduling (I've never coded
an RT app, but MIDI apps works
100% realtime for me without any upgrading of priority).
Good luck, -Harry
On Sat, Oct 3, 2009 at 2:07 PM, Carlo Capocasa <theman(a)carlocapocasa.com> wrote:
Hi,
I'm looking into doing some real time MIDI programming with either C++
or Common lisp.
I would specifically not schedule anything but deliver everything as
"play it right now" notes.
Is it necessary to use realtime scheduling the way JACK does?
Or is it ok to use normal "user mode" programs?
Your expert advice much appreciated!
Carlo
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev(a)lists.linuxaudio.org
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
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5:57 p.m.
victor wrote:
As an alternative, you can use PortMIDI. It's a
fairly simple API and
I would recommend it.
Seconded. It's very portable as well, and wrappers exist for many
programming languages (or are easy to build, as it's just plain C).
Another thing that PortMidi has going for it, is that in conjunction
with PortTime it supports timing (and scheduling), an important feature
which RtMidi seems to lack entirely. (Yes, I noticed that Carlo didn't
ask for that, but he's probably going to need it anyway, sooner or
later.) Also, I just noticed that the PortMedia project finally offers
PortSMF to read and write standard MIDI files, too, I always missed that
piece. ;-)
Talking about Midi libraries, the venerable MidiShare is still the most
complete and feature-rich I've seen. Alas, it's 32 bit only and requires
a kernel module on Linux. The Grame people have moved on to other things
(Faust, most notably), and so this library is quickly falling victim to
bitrot now. :( If there's a young Linux audio programmer interested in
MIDI and looking for a project he can cut his teeth on, porting
MidiShare to 64 bit and getting rid of the kernel module would be a very
worthwhile endeavour!
Albert
--
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email: Dr.Graef(a)t-online.de, ag(a)muwiinfa.geschichte.uni-mainz.de
WWW: http://www.musikinformatik.uni-mainz.de/ag
5:40 p.m.
Harry Van Haaren wrote:
And I'd advise you to start with
"normal" scheduling (I've never coded
an RT app, but MIDI apps works
100% realtime for me without any upgrading of priority).
That may work if you have enough spare cpu power, but otherwise you may
get a lot of jitter which really hurts with fast pieces (lots of MIDI
messages at a fast tempo).
It's really not that hard to get realtime scheduling priorities on
recent Linux systems. I wouldn't want to run any computer music
application without that. But maybe RtMidi already does that behind the
scenes?
Albert
--
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email: Dr.Graef(a)t-online.de, ag(a)muwiinfa.geschichte.uni-mainz.de
WWW: http://www.musikinformatik.uni-mainz.de/ag
4 Oct
4 Oct
2:43 p.m.
On Saturday, October 3, 2009, Albert Graef wrote:
Harry Van Haaren wrote:
No. And I don't feel it is needed at all, at least for VMPK (it is my only
program using RtMIDI at this moment).
If you are using Linux, the ALSA sequencer's MIDI routing and I/O is done in
kernel, which is usually good enough for realtime MIDI applications.
Answering to Carlo: RtMIDI is good if your goal is multiplatform (Linux, Win
and Mac) and your needs are basic. If your target is Linux only, I prefer to
work with the ALSA sequencer directly, using my wrapper for C++ and Qt4
(aseqmm).
Regards,
Pedro
And I'd advise you to start with
"normal" scheduling (I've never coded
an RT app, but MIDI apps works
100% realtime for me without any upgrading of priority).
That may work if you have enough spare cpu power, but otherwise you may
get a lot of jitter which really hurts with fast pieces (lots of MIDI
messages at a fast tempo).
It's really not that hard to get realtime scheduling priorities on
recent Linux systems. I wouldn't want to run any computer music
application without that. But maybe RtMidi already does that behind the
scenes? 
3 Oct
3 Oct
6:19 p.m.
On Sat, 2009-10-03 at 15:07 +0200, Carlo Capocasa wrote:
Hi,
I'm looking into doing some real time MIDI programming with either C++
or Common lisp.
I would specifically not schedule anything but deliver everything as
"play it right now" notes.
Is it necessary to use realtime scheduling the way JACK does?
Or is it ok to use normal "user mode" programs?
Your expert advice much appreciated!
Casting my predictable vote for Jack MIDI :)
-dr
7:31 p.m.
David Robillard wrote:
Casting my predictable vote for Jack MIDI :)
Hi David, is there a nice introduction to Jack MIDI available somewhere?
I guess that there ought to be a LAC paper about it, but a quick Google
search didn't turn up anything useful.
Albert
--
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email: Dr.Graef(a)t-online.de, ag(a)muwiinfa.geschichte.uni-mainz.de
WWW: http://www.musikinformatik.uni-mainz.de/ag
6 Oct
6 Oct
11:01 p.m.
On Sat, 2009-10-03 at 23:31 +0200, Albert Graef wrote:
David Robillard wrote:
Hm, sorry, not that I know of.
Though the API is simple, I suppose there really should be...
-dr
Casting my predictable vote for Jack MIDI :)
Hi David, is there a nice introduction to Jack MIDI available somewhere?
I guess that there ought to be a LAC paper about it, but a quick Google
search didn't turn up anything useful. 
7 Oct
7 Oct
11:18 a.m.
On Tue, Oct 06, 2009 at 09:01:35PM -0400, David Robillard wrote:
On Sat, 2009-10-03 at 23:31 +0200, Albert Graef
wrote:
There is some simple example code available at the jackaudio wiki though:
http://trac.jackaudio.org/wiki/WalkThrough/Dev/SimpleMidiClient
Arnout
David Robillard wrote:
Hm, sorry, not that I know of.
Though the API is simple, I suppose there really should be... Casting my predictable vote for Jack MIDI :)
Hi David, is there a nice introduction to Jack MIDI available somewhere?
I guess that there ought to be a LAC paper about it, but a quick Google
search didn't turn up anything useful.
8 Oct
8 Oct
2:04 a.m.
Arnout Engelen wrote:
There is some simple example code available at the
jackaudio wiki though:
http://trac.jackaudio.org/wiki/WalkThrough/Dev/SimpleMidiClient
Thanks, that looks pretty straightforward. I guess that to output MIDI
from another thread one is supposed to use a ringbuffer which is read by
the Jack callback, or is there a better solution for that?
Albert
--
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email: Dr.Graef(a)t-online.de, ag(a)muwiinfa.geschichte.uni-mainz.de
WWW: http://www.musikinformatik.uni-mainz.de/ag
12:54 p.m.
On Thu, Oct 8, 2009 at 12:03 AM, Albert Graef <Dr.Graef(a)t-online.de> wrote:
Arnout Engelen wrote:
thats the only solution :)
but keep in mind that, just as with audio, JACK is "encouraging" "RT
design" in which you do the work associated with a particular audible
time as close to that time as possible. of course, this doesn't apply
to playback of MIDI from disk, but if you're doing algorithmic
composition, the long term goal is to encourage people to write the
same that they do with audio synthesis: JACK says "its time to
generate data for the next block" and the app does it right there and
then. obviously, some mileage may vary :)
--p
There is some simple example code available at
the jackaudio wiki though:
http://trac.jackaudio.org/wiki/WalkThrough/Dev/SimpleMidiClient
Thanks, that looks pretty straightforward. I guess that to output MIDI
from another thread one is supposed to use a ringbuffer which is read by
the Jack callback, or is there a better solution for that?
1:43 p.m.
Paul Davis wrote:
but keep in mind that, just as with audio, JACK is
"encouraging" "RT
design" in which you do the work associated with a particular audible
time as close to that time as possible. of course, this doesn't apply
to playback of MIDI from disk, but if you're doing algorithmic
composition, the long term goal is to encourage people to write the
same that they do with audio synthesis: JACK says "its time to
generate data for the next block" and the app does it right there and
then. obviously, some mileage may vary :)
Yes, I understand. But I'll have to find out whether it's feasible in my
case (Jack module for Pure). Guess I'll take a look at other language
bindings and see how they do it; if it works with py-jack, then Pure
should certainly be able to do that, too.
Albert
--
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email: Dr.Graef(a)t-online.de, ag(a)muwiinfa.geschichte.uni-mainz.de
WWW: http://www.musikinformatik.uni-mainz.de/ag
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12 comments
8 participants
participants (8)
-
Albert Graef -
Arnout Engelen -
Carlo Capocasa -
David Robillard -
Harry Van Haaren -
Paul Davis -
Pedro Lopez-Cabanillas -
victor