Re: Start of Distributed MIDI Standard [...]
Re: Start of Distributed MIDI Standard [...]
- Subject: Re: Start of Distributed MIDI Standard [...]
- From: Phil Kerr <email@hidden>
- Date: Tue, 18 Feb 2003 04:42:59 +0000
Thanks John,
There has been an increasing interest in MIDI transmission over LANs
and the IEEE standard is looking provide an interoperability framework
between software and hardware in this domain.
DMIDI is designed as a lightweight Ethernet based wrapper for MIDI
data, with very low networking and implementation overheads. Device
addressing is greatly simplified when using layer 2 protocols as its
broadcast nature and unique MAC IDs provide
a hardware based solution for embedded device discovery.
DMIDI adds an addressing schema to extend the number of addressable
devices, close to 16 million, and adds an extensible meta-data schema
for additional control.
There are a number of separate networking domains for MIDI outside its
traditional networking infrastructure - host based, LAN based and
Internet based. USB and FireWire are good interfaces but Ethernet has
the advantage of wireless, over a greater distance than Bluetooth, and
at a far higher transmission speeds. Layer 2 protocols are far more
efficient than IP based protocols and this improves timing and jitter
in a LAN environment. RTP is the best protocol for MIDI data over the
Internet and MWPP offers a robust solution for this domain.
Work has begun on finalising the protocol and development of reference
applications. Drop me an email if you are interested in joining the
Working Group.
Regards
Phil
On Monday, Feb 17, 2003, at 22:41 Europe/London, John Lazzaro wrote:
Matthew Xavier Mora <email@hidden> writes:
How is this different than "MIDI over alternate transports" document
from the MMA?
The IEEE effort is doing a layer-2 Ethernet transport protocol for
MIDI.
It is based on Phil Kerr's DMIDI (www.dmidi.org), and Phil is a key
person behind the IEEE effort.
Concurrently, there is an IETF effort in the AVT Working Group (home
of RTP, the VoIP and content-streaming standard) to define an RTP
payload for MIDI, and SDP arameters for configuring MIDI sessions
set up by SIP, RTSP, etc.
http://www.cs.berkeley.edu/~lazzaro/sa/pubs/txt/current-mwpp.txt
http://www.cs.berkeley.edu/~lazzaro/sa/pubs/txt/current-guide.txt
The MMA document is best seen as advice written to folks doing new
transport design for MIDI, so that they are aware of issues in doing
new transports for MIDI early in the design process.
The IEEE and IETF efforts overlap somewhat, but come from different
directions -- the RTP work started out as a WAN network music
performance
project here at Berkeley:
http://www.cs.berkeley.edu/~lazzaro/sa/pubs/pdf/nossdav01.pdf
and then in the standardization process became more general, to
support both content-streaming, and potentially LAN applications.
However, as an RTP payload, it is designed to work within the IETF
framework of tools -- SDP for session description, SIP and RTSP for
session management, and for stand-alone embedded devices in a LAN
context, a way to find your IP number and DNS name, like DHCP or
Rendevous. Because the IEEE effort is layer-2, all of that session
management stuff happens in a much different way, that lives in
a world of MAC addresses and not IP numbers.
I'm sure Phil and Jim Wright are both listening in and will comment
soon, if they haven't already ...
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John Lazzaro -- Research Specialist -- CS Division -- EECS -- UC
Berkeley
lazzaro [at] cs [dot] berkeley [dot] edu
www.cs.berkeley.edu/~lazzaro
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