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On Wed=2C Dec 28=2C 2011 at 1:46 PM=2C Iain Duncan  wrote:

quoted text
> Hey folks=2C what is the easiest way to deal with midi input in a jack ap=

p?

Dave mentioned that you want to use the Jack API entirely=2C I think he pro=

bably meant

that on Linux you can safely rely in having an access method that just take=

s MIDI=20
from Jack - then converts to whatever messaging you want within your app. I=

 may
be wrong. The issue is that you put in that extremely awkward caveat which =

was "easy=20

to port to other systems". I would not really want to have my whole source =

code having=20

a line like #include  to work. Even if that line is in a p=

rivate=2C global=20

header file it implies the code is dependent and that reduces portability.
If you want maximum portability you probably need to create your own intern=

al

event messaging format and have raw MIDI=2C ALSA MIDI=2C Jack MIDI (or OSC=

=2C or

Portmidi=2C etc) map into it using libraries.
It is a bit more work but fortunately there is a reasonable amount of commo=

nality

in the external formats so your library will mostly be concerned with what =

is the

access method to those data formats rather than the format itself.
Not sure if that answers your question. You asked what was the easiest way.=

 The

easiest way is get somebody else do to it but I think your own your own her=

e? The

main thing you want to avoid is that when you pass these 'musical event' me=

ssages

around your application that you are relying on a format from somebody else=

' library

since if you try and port that over to another system you will have a depen=

dency on

what might be a non-native interface on that other system.
If you are going to support lots of different interfaces then you get into =

some really=20

enjoyable special cases. For example=2C when MIDI is not delivered into the=

 RT audio

thread you need a ringbuffer to send at least some of the messages to that =

thread.

Conversely when you use Jack you have to decide which messages are not real=

ly for

the RT thread and throw them the other way on another such ringbuffer. When=

 you

talk about having multiple MIDI interfaces you will be directly affect by t=

hese issues

at the same time.
> what is the easiest way to deal with midi input in a jack app?
Hm=2C there might not actually be an answer to this question since you put =

in that=20

damn caveat - you don't actually seem to want a Jack application.=20
Have fun. Or=2C if you can=2C get somebody else to have that 'fun' for you.
Kind regards=2C nick.
"we have to make sure the old choice [Windows] doesn't disappear=94.

Jim Wong=2C president of IT products=2C Acer
Date: Wed=2C 28 Dec 2011 10:46:29 -0800

From: iainduncanlists@gmail.com

To: linux-audio-dev@lists.linuxaudio.org

Subject: [LAD] handling midi input in a jack app?
Hey folks=2C what is the easiest way to deal with midi input in a jack app?=

 I'm confused by the difference in jack midi and alsa midi=2C because I hav=

e two midi inputs=2C one is a usb input=2C so it appears at a low level as =

an alsa device=2C but the other is the midi input on a firewire unit=2C and=

 it appears as a jack midi device. I'd like to make sure that whatever I do=

 is easy to port to other systems. Does it make sense to use portmidi or rt=

midi to get input or should I stick to the jack api entirely?
thanksIain
_______________________________________________

Linux-audio-dev mailing list

Linux-audio-dev@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-dev 		 	   		  =
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Content-Type: text/html; charset="Windows-1252"

Content-Transfer-Encoding: quoted-printable
On Wed=2C Dec 28=2C 2011 at 1:46 PM=2C Iain Duncan &lt=3Biainduncanlis=

ts@gmail.com&gt=3B wrote:&gt=3B Hey folks=2C what is the easiest way to=

 deal with midi input in a jack app?Dave mentioned that you want =

to use the Jack API entirely=2C I think he probably meant

that on Linux you can safely rely in having an access method that just take=

s MIDI

from Jack - then converts to whatever messaging you want within your app. I=

 may

be wrong. The issue is that you put in that extremely awkward caveat which =

was "easy to port to other systems". I would not really want to have my=

 whole source code having a line like #include &lt=3Bjack/midiport.h&gt=

=3B to work. Even if that line is in a private=2C global header file it=

 implies the code is dependent and that reduces portability.
If you want maximum portability you probably need to create your own intern=

alevent messaging format and have raw MIDI=2C ALSA MIDI=2C Jack MIDI (o=

r OSC=2C orPortmidi=2C etc) map into it using libraries.It is a=

 bit more work but fortunately there is a reasonable amount of commonality<=

br>in the external formats so your library will mostly be concerned with wh=

at is theaccess method to those data formats rather than the format its=

elf.Not sure if that answers your question. You asked what was the =

easiest way. Theeasiest way is get somebody else do to it but I think y=

our own your own here? Themain thing you want to avoid is that when you=

 pass these 'musical event' messagesaround your application that you ar=

e relying on a format from somebody else' librarysince if you try and p=

ort that over to another system you will have a dependency onwhat might=

 be a non-native interface on that other system.If you are going to=

 support lots of different interfaces then you get into some really enj=

oyable special cases. For example=2C when MIDI is not delivered into the RT=

 audiothread you need a ringbuffer to send at least some of the message=

s to that thread.Conversely when you use Jack you have to decide which =

messages are not really forthe RT thread and throw them the other way o=

n another such ringbuffer. When youtalk about having multiple MIDI inte=

rfaces you will be directly affect by these issuesat the same time.=

&gt=3B what is the easiest way to deal with midi input in a jack app?Hm=2C there might not actually be an answer to this question since yo=

u put in that damn caveat - you don't actually seem to want a Jack appl=

ication. Have fun. Or=2C if you can=2C get somebody else to have th=

at 'fun' for you.Kind regards=2C nick."we have to make sure=

 the old choice [Windows] doesn't disappear=94.Jim Wong=2C president of=

 IT products=2C Acer=

Date: Wed=2C 28 Dec 2011 10:46:29 -0800From: ia=

induncanlists@gmail.comTo: linux-audio-dev@lists.linuxaudio.orgSubj=

ect: [LAD] handling midi input in a jack app?Hey folks=2C what=

 is the easiest way to deal with midi input in a jack app? I'm confused by =

the difference in jack midi and alsa midi=2C because I have two midi inputs=

=2C one is a usb input=2C so it appears at a low level as an alsa device=2C=

 but the other is the midi input on a firewire unit=2C and it appears as a =

jack midi device. I'd like to make sure that whatever I do is easy to port =

to other systems. Does it make sense to use portmidi or rtmidi to get input=

 or should I stick to the jack api entirely?

thanksIain

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Linux-audio-dev mailing list

Linux-audio-dev@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-dev

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