Subject: [AVT] [Technical Errata Reported] RFC4695 (2673)

From: RFC Errata System <[email-masked]>
Date: Sat, 18 Dec 2010 13:40:04 -0800 (PST)

The following errata report has been submitted for RFC4695,
"RTP Payload Format for MIDI".

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You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=4695&eid=2673

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Type: Technical
Reported by: John Lazzaro <[email-masked]>

Section: 3

Original Text
-------------

   If the LEN header field is nonzero, the MIDI list has the structure
   shown in Figure 3.

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Delta Time 0     (1-4 octets long, or 0 octets if Z = 1)     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  MIDI Command 0   (1 or more octets long)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Delta Time 1     (1-4 octets long)                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  MIDI Command 1   (1 or more octets long)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                              ...                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Delta Time N     (1-4 octets long)                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  MIDI Command N   (0 or more octets long)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 3 -- MIDI list structure

Corrected Text
--------------

   If the LEN header field is nonzero, the MIDI list has the structure
   shown in Figure 3.

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Delta Time 0     (1-4 octets long, or 0 octets if Z = 0)     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  MIDI Command 0   (1 or more octets long)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Delta Time 1     (1-4 octets long)                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  MIDI Command 1   (1 or more octets long)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                              ...                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Delta Time N     (1-4 octets long)                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  MIDI Command N   (0 or more octets long)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 3 -- MIDI list structure

Notes
-----
The sole change here is in the parenthesized text that follows
the "Delta Time 0" name in the first bitfield shown in Figure 3.
RFC 4695 has "1-4 octets long, or 0 octets if Z = 1".  This 
does not match the definition of Z in the main text.  The corrected
figure text is: "1-4 octets long, or 0 octets if Z = 0".  Thankfully, all 
known implementations follow the main text in this
regard, so this bug should not have resulted in interoperability
issues.  This bug has been fixed in the bis I-D intended to
obsolete RFC 4695 that is currently in Last Call in AVT.

Instructions:
-------------
This errata is currently posted as "Reported". If necessary, please
use "Reply All" to discuss whether it should be verified or
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can log in to change the status and edit the report, if necessary. 

--------------------------------------
RFC4695 (draft-ietf-avt-rtp-midi-format-15)
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Title               : RTP Payload Format for MIDI
Publication Date    : November 2006
Author(s)           : J. Lazzaro, J. Wawrzynek
Category            : PROPOSED STANDARD
Source              : Audio/Video Transport
Area                : Real-time Applications and Infrastructure
Stream              : IETF
Verifying Party     : IESG

---

From: John Lazzaro <[email-masked]>
Date: Sat, 18 Dec 2010 13:43:59 -0800

Hi everyone,

This is an errata I entered into the RFC Errata system,
based on a bug Roni found in the bis I-D during last call.
Since the typo could result in incorrect implementations, I
thought it was appropriate to add it as an RFC 4695 errata.

Thus, I recommended verification of the errata by the IESG.

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