RFC 5404, "RTP Payload Format for G.719", January 2009

Errata ID: 1669
Status: Held for Document Update
Type: Editorial
Publication Format(s) : TEXT
Reported By: Alfred Hoenes
Date Reported: 2009-01-26
Held for Document Update by: Cullen Jennings
Date Held: 2009-01-28

Section 7.1, pg.18 says:

   CBR:  Constant Bitrate (CBR) indicates the exact codec bitrate in
      bits per second (not including the overhead from packetization,
      RTP header, or lower layers) that the codec MUST use.  "CBR" is to
      be used when the dynamic rate cannot be supported (one case is,
      e.g., gateway to H.320).  "CBR" is mostly used for gateways to
|     circuit switch networks.  Therefore, the "CBR" is the rate not
      including any FEC as specified in Section 4.3.1.  If FEC is to be
|     used, the "b=" parameter MUST be used to allow the extra bitrate
      needed to send the redundant information.  [...]

It should say:

   CBR:  Constant Bitrate (CBR) indicates the exact codec bitrate in
      bits per second (not including the overhead from packetization,
      RTP header, or lower layers) that the codec MUST use.  "CBR" is to
      be used when the dynamic rate cannot be supported (one case is,
      e.g., gateway to H.320).  "CBR" is mostly used for gateways to
|     circuit switched networks.  Therefore, the "CBR" is the rate not
      including any FEC as specified in Section 4.3.1.  If FEC is to be
|     used, the "b=" SDP parameter MUST be used to allow the extra
      bitrate needed to send the redundant information.  [...]

Notes:

Rationale:

a) Typo; s/circuit switch/circuit switched/

b) In the context of the discussion of media type parameters,
also using the unqualified term "parameter" for an SDP parameter
is rather confusing; for clarity, "SDP" needs to be inserted.

Additional note from authors of RFC ...

This text should probably not talk about SDP
parameters at all, but rather the need for external functionality that
indicates the actual bitrate of the RTP session as due to the
FEC/Redundancy the CBR value is not a good indicator of the total bitrate.

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