From: "Tony Nelson" <tonynelson@xxxxxxxxxxxxxxxxx>
At 8:28 PM -0800 11/11/06, jdow wrote:
From: "Tony Nelson" <tonynelson@xxxxxxxxxxxxxxxxx>
At 9:41 PM -0500 11/11/06, Gene Heskett wrote:
On Saturday 11 November 2006 21:00, Tony Nelson wrote:
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.
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.
It's already done. MIDI runs over Firewire, along with audio. Google for
"midi firewire". Buy it now.
Look at its specs. It is designed to closely mimic wire transport. So
any given chunk of virtual wire is going to be as slow as MIDI wires.
...
How can that be? MIDI latency is determined by the bit rate of serial
transport. Firewire MIDI latency is improved by the high bit rate, delayed
only by the 8 per ms Isoch frame rate. There's no need for greater than
1/4 ms latency on Firewire MIDI for even a large number of MIDI events
(notes, aftertouch, what have you).
They put in intentional delays is what it amounts to. (RTP MIDI also
does this by default. It can be set to a prompt delivery mode, I
believe. It is ALMOST a standard. And the Apple simplified RTP is also
being considered for standardization. Both have to make MMA happy as
well as the other standards organizations involved.)
{^_^}
