RFC 3264, "An Offer/Answer Model with Session Description Protocol (SDP)", June 2002

Note: This RFC has been updated by RFC 6157, RFC 8843, RFC 9143

Errata ID: 7597
Status: Rejected
Type: Technical
Publication Format(s) : TEXT
Reported By: Hugo Tunius
Date Reported: 2023-08-11
Rejected by: Orie Steele
Date Rejected: 2024-05-09

Section 6.1 says:

   The interpretation of fmtp parameters in an offer depends on the
   parameters.  In many cases, those parameters describe specific
   configurations of the media format, and should therefore be processed
   as the media format value itself would be.  This means that the same
   fmtp parameters with the same values MUST be present in the answer if
   the media format they describe is present in the answer.  Other fmtp
   parameters are more like parameters, for which it is perfectly
   acceptable for each agent to use different values.  In that case, the
   answer MAY contain fmtp parameters, and those MAY have the same
   values as those in the offer, or they MAY be different.  SDP
   extensions that define new parameters SHOULD specify the proper
   interpretation in offer/answer.

It should say:

   The interpretation of fmtp parameters in an offer depends on the
   parameters.  In many cases, those parameters describe specific
   configurations of the media format, and should therefore be processed
   as the media format value itself would be.  This means that the same
   fmtp parameters with the same values MUST be present in the answer if
   the media format they describe is present in the offer.  Other fmtp
   parameters are more like parameters, for which it is perfectly
   acceptable for each agent to use different values.  In that case, the
   answer MAY contain fmtp parameters, and those MAY have the same
   values as those in the offer, or they MAY be different.  SDP
   extensions that define new parameters SHOULD specify the proper
   interpretation in offer/answer.

Notes:

This indicated that the same fmtp parameters with the same values MUST be present in the answer if the media format they describe is present in the **answer**.

I believe the second instance of **answer** should be replace with **offer**, otherwise the quoted text does not makes sense I think.
--VERIFIER NOTES--
See https://mailarchive.ietf.org/arch/msg/mmusic/jDXva6XmGQ4Z6_PUW_TxhZp0-Hc/

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