[sdiy] OT: sequencing over the internet

[Colin Fraser]

> -----Original Message-----
> From: owner-synth-diy at node12b53.a2000.nl
> [mailto:owner-synth-diy at node12b53.a2000.nl]On Behalf Of Glen
> Sent: 14 March 2001 16:03
> To: synth-diy at node12b53.a2000.nl
> Subject: RE: [sdiy] OT: sequencing over the internet
>
> This topic makes me wonder if it would be practical to write
> some sort of
> MIDI drivers which would send MIDI info over a LAN, instead
> of MIDI cables,
> at higher speeds than standard MIDI?

Despite it's lack of speed, with MIDI you only need to send the data once,
and it arrives a predictable time after you sent it.

With a multiple access networks (eg ethernet LAN), there is no guarantee
that you can successfully transmit data at any given time - something else
may collide with your data and your have to wait then re-transmit it.
The net result (sorry) being that you can't be sure precisely when your data
will get to it's destination.

To maintain a stream of data at the receiving end you need to deliberately
introduce latency by filling up a buffer with data as it arrives in bursts,
then read out the data from your buffer as a continuous stream.
As long as you don't want to read data from the buffer faster than the
average rate it is arriving, your buffer won't underflow.
( but how often does that happen when you're watching Real Video ;-) )

Any more latency than 5 ms or so, and you start getting Jazzy again...

> I think Yamaha or Roland are working on something similar, but their
> solution utilizes custom hardware installed on hardware synth
> modules,

They are introducing mLan on various new products - which transmits Midi and
audio data over a 1394 firewire connection.

http://www.yamaha.co.jp/tech/1394mLAN/Technical/mlan.html

This has a lot more promise than trying to fit the round peg of audio and
midi into the square hole of ethernet.
The key is real-time data transmission.


Colin f