11 Nov
2006
11 Nov
'06
10:41 p.m.
On Saturday 11 November 2006 21:00, Tony Nelson wrote:
More robust IMO than the din connectors now used for midi interconnects,
however the cabling itself can't help but be more fragile when subjected
to the rigors of a jam session with bodies walking on them all night.
And that has to be a consideration else the first users will get
discouraged at the high cable failure rates and revert, particularly if
they have a tin ear and can't hear what to many of us would be an
extremely obvious improvement.
But I like that idea, a lot. Maybe some enterprising LAD people could get
together and spec something like a midi interface running over firewire,
complete with the repeaters so it can be daisy-chained just like midi can
be, and hopefully release it into the PD as a new midi-2 interface
standard. And design it such that it never, ever gets into the snails
trail of the 31,250 baud interface it uses today.
--
Cheers, Gene
At 4:21 PM -0500 11/11/06, Gene Heskett wrote:
...
This thread might be of interest to the linux-audio-dev group, so I've
added them to the Cc:
Yup, and its
been a constant src of amazement to this old fart that
when the midi spec was setup, they used a serial port, thats fine, but
when they set the data rate at only 31,250 baud, ...
Consistently attrocious timeing, with the horns always 1/16 beat late
unless the actual output order of each instrument is scrambled in the
order output. That would make it sound a heck of a lot less
mechanical. And there isn't a heck of a lot that can be done until we
put midi on an optical circuit running at several megabytes/sec.
Something like TOS maybe?
Firewire. Many products already, plenty of speed, almost robust enough.
1/8 millisecond isoch cycle times; each cycle can contain packets from
many senders; each packet can contain lots of notes. 
12 Nov
12 Nov
7:17 a.m.
On Sat, 2006-11-11 at 21:41 -0500, Gene Heskett wrote:
But I like that idea, a lot. Maybe some enterprising
LAD people could get
together and spec something like a midi interface running over firewire,
complete with the repeaters so it can be daisy-chained just like midi can
be, and hopefully release it into the PD as a new midi-2 interface
standard. And design it such that it never, ever gets into the snails
trail of the 31,250 baud interface it uses today.
MIDI over IEEE-1394 (aka firewire) exists and is spec'ed by the MMA
midi-consortium as an official standard. Unlike other publications from
the MMA, this is a free download:
http://www.midi.org/about-midi/rp27v10spec(1394).pdf
--
7:39 a.m.
On Sunday 12 November 2006 06:16, Jens M Andreasen wrote:
On Sat, 2006-11-11 at 21:41 -0500, Gene Heskett wrote:
Great! I guess I hadn't been paying attention. Thank you very much for
the link.
--
Cheers, Gene
But I like that idea, a lot. Maybe some
enterprising LAD people could
get together and spec something like a midi interface running over
firewire, complete with the repeaters so it can be daisy-chained just
like midi can be, and hopefully release it into the PD as a new midi-2
interface standard. And design it such that it never, ever gets into
the snails trail of the 31,250 baud interface it uses today.
MIDI over IEEE-1394 (aka firewire) exists and is spec'ed by the MMA
midi-consortium as an official standard. Unlike other publications from
the MMA, this is a free download:
http://www.midi.org/about-midi/rp27v10spec(1394).pdf 
12:28 p.m.
Gene Heskett wrote:
On Sunday 12 November 2006 06:16, Jens M Andreasen
wrote:
Note that this is already implemented in FreeBob. There is nothing
preventing us from setting up a (random number here)-channel MIDI link
over Firewire between one or more devices.
A major issue however is discovering the devices and negotiating a
common stream format. This is not specified by the MMA, this spec only
describes the actual transfer of the MIDI bytes.
Another showstopper is that every sender will need his own firewire
isochronous channel to send its data on, so that limits the number of
devices to 16. Keep in mind that the Firewire bus is one single domain
(for the Isochronous traffic), i.e. everybody sees everything.
When using asynchronous traffic these restrictions don't apply but then
you lose the 'broadcast' advantage, making everything more complex.
Pieter
On Sat, 2006-11-11 at 21:41 -0500, Gene Heskett
wrote:
Great! I guess I hadn't been paying attention. Thank you very much for
the link.
But I like that idea, a lot. Maybe some
enterprising LAD people could
get together and spec something like a midi interface running over
firewire, complete with the repeaters so it can be daisy-chained just
like midi can be, and hopefully release it into the PD as a new midi-2
interface standard. And design it such that it never, ever gets into
the snails trail of the 31,250 baud interface it uses today.
MIDI over IEEE-1394 (aka firewire) exists and is spec'ed by the MMA
midi-consortium as an official standard. Unlike other publications from
the MMA, this is a free download:
http://www.midi.org/about-midi/rp27v10spec(1394).pdf
12:45 p.m.
What is a really major issue, that all hw synths still have that slow
31.5kbps link.
Nonetheless, glad to hear FW-MIDI being that fast. And what about jitter there?
According to RME guys, without special handling USB-MIDI can suffer
delays about 6ms.
And with FW, they state there are the same problems (no numbers here)
and their Fireface has exceptional MIDI timing, comparing to all other
FW-offerings.
What do you think?
Dmitry.
1:37 p.m.
Dmitry Baikov wrote:
What is a really major issue, that all hw synths still
have that slow
31.5kbps link.
Nonetheless, glad to hear FW-MIDI being that fast. And what about
jitter there?
According to RME guys, without special handling USB-MIDI can suffer
delays about 6ms.
true
And with FW, they state there are the same problems
(no numbers here)
and their Fireface has exceptional MIDI timing,
comparing to all other
FW-offerings.
There is jitter on the firewire bus clock too, but not nearly as bad as
USB.
The timing resolution for a byte on a FW-MIDI channel is 125us (compared
to 250us for normal MIDI). The jitter present on the ISO clock is
magnitudes lower hence doesn not play a significant role.
I'd like to see the technical motivation for this RME statement.
Pieter
30 Nov
30 Nov
2:44 p.m.
On Sun, 2006-11-12 at 17:28 +0100, Pieter Palmers wrote:
[regarding midi over firewire]
Note that this is already implemented in FreeBob.
There is nothing
preventing us from setting up a (random number here)-channel MIDI link
over Firewire between one or more devices.
A major issue however is discovering the devices and negotiating a
common stream format. This is not specified by the MMA, this spec only
describes the actual transfer of the MIDI bytes.
Pieter, I am not sure that I follow you correctly here. Using bad
car-anology: Is this like as if you have already build "The Golden Gate
Bridge", but there are still no "Highways" connecting to it? That there
is a sinc to throw the bytes into but no way for alsa to know about it?
In other words; is a device like M-Audio's 4ch audio in/out + 3 octave
keyboard useful as a performance instrument under Linux, or will the
keyboard be dead?
Another showstopper is that every sender will need his
own firewire
isochronous channel to send its data on, so that limits the number of
devices to 16. Keep in mind that the Firewire bus is one single domain
(for the Isochronous traffic), i.e. everybody sees everything.
Uhmm yes, but as I read from the paper, the midi transfer rate is (or
can be) quadrupled. Given that a home/stage setup with a single player
on a single cable works just fine latency-wise, wouldn't then 16*4 be
quite enough? At the risk of paraphrazing Bill Gates, but 64 staves
ought to be enough for anyone ... You could fit in two symphonic
orchestras, mixed choir, a couple of organs, a big band as well as an
extended Irish folk-group into that budget (and then some.)
Jokes aside: I don't see any external firewire computing devices where
one could send all those midi2 messages to. Anyone else?
When using asynchronous traffic these restrictions
don't apply but then
you lose the 'broadcast' advantage, making everything more complex.
Pieter
--
12 Nov
12 Nov
9:20 p.m.
On Sat, 2006-11-11 at 21:41 -0500, Gene Heskett wrote:
On Saturday 11 November 2006 21:00, Tony Nelson
wrote:
More robust IMO than the din connectors now used for midi interconnects,
however the cabling itself can't help but be more fragile when subjected
to the rigors of a jam session with bodies walking on them all night.
And that has to be a consideration else the first users will get
discouraged at the high cable failure rates and revert, particularly if
they have a tin ear and can't hear what to many of us would be an
extremely obvious improvement.
But I like that idea, a lot. Maybe some enterprising LAD people could get
together and spec something like a midi interface running over firewire,
complete with the repeaters so it can be daisy-chained just like midi can
be, and hopefully release it into the PD as a new midi-2 interface
standard. And design it such that it never, ever gets into the snails
trail of the 31,250 baud interface it uses today.
Forget Firewire - Ethernet!
Far cheaper, far more common, more hardware available (eg switches)
-DR-
At 4:21 PM -0500 11/11/06, Gene Heskett wrote:
...
This thread might be of interest to the linux-audio-dev group, so I've
added them to the Cc:
Yup, and
its been a constant src of amazement to this old fart that
when the midi spec was setup, they used a serial port, thats fine, but
when they set the data rate at only 31,250 baud, ...
Consistently attrocious timeing, with the horns always 1/16 beat late
unless the actual output order of each instrument is scrambled in the
order output. That would make it sound a heck of a lot less
mechanical. And there isn't a heck of a lot that can be done until we
put midi on an optical circuit running at several megabytes/sec.
Something like TOS maybe?
Firewire. Many products already, plenty of speed, almost robust enough.
1/8 millisecond isoch cycle times; each cycle can contain packets from
many senders; each packet can contain lots of notes. 
14 Nov
14 Nov
6:33 p.m.
Don't forget DMIDI IEEE P1639. Distributed MIDI over ethernet. It is still
alive and well and I'm developing code for other Os's apart from Linux. Also
working on a MIDI BOX with 32 MIDI ins and 32 MIDI outs all separately
addressable and just plugs into a 10/100/1000 ethernet hub/switch.
regards,
Jennifer Dillon
Dave Robillard writes:
On Sat, 2006-11-11 at 21:41 -0500, Gene Heskett
wrote:
On Saturday 11 November 2006 21:00, Tony Nelson
wrote:
More robust IMO than the din connectors now used for midi interconnects,
however the cabling itself can't help but be more fragile when subjected
to the rigors of a jam session with bodies walking on them all night.
And that has to be a consideration else the first users will get
discouraged at the high cable failure rates and revert, particularly if
they have a tin ear and can't hear what to many of us would be an
extremely obvious improvement.
But I like that idea, a lot. Maybe some enterprising LAD people could get
together and spec something like a midi interface running over firewire,
complete with the repeaters so it can be daisy-chained just like midi can
be, and hopefully release it into the PD as a new midi-2 interface
standard. And design it such that it never, ever gets into the snails
trail of the 31,250 baud interface it uses today.
Forget Firewire - Ethernet!
Far cheaper, far more common, more hardware available (eg switches)
-DR-
At 4:21 PM -0500 11/11/06, Gene Heskett wrote:
...
This thread might be of interest to the linux-audio-dev group, so I've
added them to the Cc:
Yup, and
its been a constant src of amazement to this old fart that
when the midi spec was setup, they used a serial port, thats fine, but
when they set the data rate at only 31,250 baud, ...
Consistently attrocious timeing, with the horns always 1/16 beat late
unless the actual output order of each instrument is scrambled in the
order output. That would make it sound a heck of a lot less
mechanical. And there isn't a heck of a lot that can be done until we
put midi on an optical circuit running at several megabytes/sec.
Something like TOS maybe?
Firewire. Many products already, plenty of speed, almost robust enough.
1/8 millisecond isoch cycle times; each cycle can contain packets from
many senders; each packet can contain lots of notes. 
8 p.m.
Some stuff to read for Ethernet Midi, here is a Real Time Transport
protocol for Midi over network:
http://tools.ietf.org/html/rfc4695
Cheers,
Malte
--
Malte Steiner
media art + development
-www.block4.com-
6357
days inactive
6376
days old
linux-audio-dev@lists.linuxaudio.org
9 comments
7 participants
participants (7)
-
Dave Robillard -
Dmitry Baikov -
Gene Heskett -
Jennifer Dillon -
Jens M Andreasen -
Malte Steiner -
Pieter Palmers