





Network Working Group                                            R. Even
Request for Comments: 4628                                       Polycom
Category: Informational                                     January 2007


    RTP Payload Format for H.263 Moving RFC 2190 to Historic Status

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   The first RFC that describes an RTP payload format for ITU
   Telecommunication Standardization Sector (ITU-T) recommendation H.263
   is RFC 2190.  This specification discusses why to move RFC 2190 to
   historic status.

Table of Contents

   1. Introduction ....................................................2
   2. Terminology .....................................................2
   3. Recommendation ..................................................2
   4. Security Considerations .........................................3
   5. Normative References ............................................3
   6. Informative References ..........................................3



















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1.  Introduction

   The ITU-T recommendation H.263 [H263] specifies the encoding used by
   ITU-T-compliant video-conference codecs.  The first version (version
   1) was approved in 1996 by the ITU, and a payload format for
   encapsulating this H.263 bitstream in the Real-time Transport
   Protocol (RTP) is in RFC 2190 [RFC2190].  In 1998 the ITU approved a
   new version of H.263 [H263P] that is also known as H.263 plus.  This
   version added optional features, and a new payload format is now in
   RFC 2429 [RFC2429].  RFC 2429 is capable of carrying encoded video
   bit streams that are using only the basic H.263 version 1 options.

   RFC 2429 [RFC2429] states that it does not replace RFC 2190, which
   continues to be used by existing implementations and may be required
   for backward compatibility in new implementations.  Implementations
   using the new features of the 1998 version of H.263 and later
   versions shall use the format described in RFC 2429.

   RFC 2429 is now being revised and will include language that will
   make it clear that all new implementations MUST use RFC 4629
   [RFC4629] for encoding of any version of H.263.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119] and
   indicate requirement levels for compliant RTP implementations.

3.  Recommendation

   RFC 2429 and RFC 4629 [RFC4629] can be used to carry new H.263
   payloads even if they are using only the features defined in the 1996
   version.  All the H.263 features that are part of the 1996 version
   are also part of the 1998 version and later versions.

   It is recommended that RFC 2190 be moved to historic status and that,
   as stated in RFC 4629 [RFC4629], new implementations use the RFC 4629
   and the H263-1998 and H263-2000 Media Types.

   This recommendation will come into effect at the publication or as
   soon as possible after the publication of RFC 4629 [RFC4629].









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4.  Security Considerations

   Security considerations for the H263 video RTP payload can be found
   in the RFC 4629 [RFC4629].  Using the payload specification in RFC
   4629 instead of that in RFC 2190 does not affect the security
   consideration since both of them refer to RFC 3550 [RFC3550] and RFC
   3551 [RFC3551] for security considerations.

5.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

6.  Informative References

   [H263]     International Telecommunication Union, "Video coding for
              low bit rate communication", ITU Recommendation H.263,
              March 1996.

   [H263P]    International Telecommunication Union, "Video coding for
              low bit rate communication", ITU Recommendation H.263,
              January 2005.

   [RFC2190]  Zhu, C., "RTP Payload Format for H.263 Video Streams", RFC
              2190, September 1997.

   [RFC2429]  Bormann, C., Cline, L., Deisher, G., Gardos, T., Maciocco,
              C., Newell, D., Ott, J., Sullivan, G., Wenger, S., and C.
              Zhu, "RTP Payload Format for the 1998 Version of ITU-T
              Rec. H.263 Video (H.263+)", RFC 2429, October 1998.

   [RFC3550]  Schulzrinne, H., Casner, S., Frederick, R., and V.
              Jacobson, "RTP: A Transport Protocol for Real-Time
              Applications", STD 64, RFC 3550, July 2003.

   [RFC3551]  Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
              Video Conferences with Minimal Control", STD 65, RFC 3551,
              July 2003.

   [RFC4629]  Ott, J., Borman, C., Sullivan, G., Wenger, S., and R.
              Even, Ed., "RTP Payload Format for ITU-T Rec. H.263
              Video", RFC 4629, January 2007.









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Author's Address

   Roni Even
   Polycom
   94 Derech Em Hamoshavot
   Petach Tikva  49130
   Israel

   EMail: roni.even@polycom.co.il










































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