Subject: [AVT] Errata report on erratum 2673 on RFC 4695 ("RTP Payload Format for MIDI") and erratum 2119 on RFC 5506 ("Support for Reduced-Size RTCP: Opportunities and Consequences")

From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Mon, 24 Jan 2011 16:14:41 -0500

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RFC4695, "RTP Payload Format for MIDI"
Source of RFC: avt (rai)

Errata ID: 2673

Status: Reported
Type: Technical

Reported By: John Lazzaro
Date Reported: 2010-12-18

Section 3 says:

   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

It should say:

   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.
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Recommended status:  (correct) Hold for document update

The erratum appears to be correct, and given the submitter is an
author of both RFC 4695 and draft-ietf-avt-rfc4695-bis, there is no
reason to doubt that.  I recommend "Hold for document update" only
because a -bis I-D is in WGLC, otherwise "Publish" would be needed.
======================================================================
RFC5506, "Support for Reduced-Size RTCP: Opportunities and Consequences"
Source of RFC: avt (rai)

Errata ID: 2119

Status: Reported
Type: Editorial

Reported By: Alfred Hoenes
Date Reported: 2010-04-05

Section 3.4.5 says:

|  o  Compression of RTCP: No IETF-defined header compression method
      compress RTCP; however, if such methods are developed in the
|     future, these methods must take Reduced-Size RTCP in account.

It should say:

|  o  Compression of RTCP: No IETF-defined header compression methods
      compress RTCP; however, if such methods are developed in the
|     future, these methods must take Reduced-Size RTCP into account.

Notes:

Rationale: singular/plural mismatch; language improvement.
----------------------------------------------------------------------
Recommended status:  (correct) Hold for document update

Or one might correct the text to "No IETF-defined header compression
>>method compresses<< RTCP...".
======================================================================

Dale