Subject: [AVT] Updated RTP MIDI I-Ds ...

From: lazzaro <[email-masked]>
Date: Wed, 10 Aug 2005 12:39:36 -0700

Hi everyone,

         Sent off the updated versions of the RTP MIDI payload
format document (draft-ietf-avt-rtp-midi-format-11.txt) and
implementation guide (draft-ietf-avt-rtp-midi-guidelines-11.txt)
to [email-masked] yesterday.  Pick up copies here:

http://www.cs.berkeley.edu/~lazzaro/sa/pubs/txt/current-rtp-midi.txt
http://www.cs.berkeley.edu/~lazzaro/sa/pubs/txt/current-guide.txt

         This revision is in response to a use of MIDI Control
Change commands that is quite popular in certain product
types, but which is not an official part of the MIDI standard.
Namely, the use of rotary encoders ("infinite" rotary knobs,
that can be turned "forever" in either direction) along with
LED displays around the knobs, to make "soft knobs".  The
devices send Change Control commands that code small
changes in rotation (a rotation angle + direction) to a host
computer, which then compute the new LED display position
and sends it back to the device.

     The -10.txt (previous I-D version) recovery journal design
provides a decent user experience when recovering from mild
packet loss of these incremental knob moves, but for heavy
losses it will be disconcerting to the user (the knob is turned
but the LEDs stay put).  Although its not actually an "indefinite
artifact" (the user is aware of the correct current knob position),
it was easy to change Chapter C in a backward-compatible way
to support a better user experience, and so I added this to the
design.  See the Change Log of format-11 for details.

     I also kept the Change Log for -09, which contains documentation
of the fixes Magnus requested in order to be ready for Last Call.
Once Magnus OKs those, and once MIDI-oriented folks have a
chance to respond to the new Chapter C changes, I think we'll
be ready for Last Call ...

---
John Lazzaro
http://www.cs.berkeley.edu/~lazzaro
lazzaro [at] cs [dot] berkeley [dot] edu
---

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