RTP Payload Format for Society of Motion Picture and Television Engineers (SMPTE) 292M Video
RFC 3497

Document Type RFC - Proposed Standard (March 2003; No errata)
Last updated 2015-10-14
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Network Working Group                                          L. Gharai
Request for Comments: 3497                                    C. Perkins
Category: Standards Track                                        USC/ISI
                                                              G. Goncher
                                                               Tektronix
                                                               A. Mankin
                                           Bell Labs, Lucent Corporation
                                                              March 2003

                        RTP Payload Format for
 Society of Motion Picture and Television Engineers (SMPTE) 292M Video

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This memo specifies an RTP payload format for encapsulating
   uncompressed High Definition Television (HDTV) as defined by the
   Society of Motion Picture and Television Engineers (SMPTE) standard,
   SMPTE 292M.  SMPTE is the main standardizing body in the motion
   imaging industry and the SMPTE 292M standard defines a bit-serial
   digital interface for local area HDTV transport.

1.  Introduction

   The serial digital interface, SMPTE 292M [1], defines a universal
   medium of interchange for uncompressed High Definition Television
   (HDTV) between various types of video equipment (cameras, encoders,
   VTRs, etc.).  SMPTE 292M stipulates that the source data be in 10 bit
   words and the total data rate be either 1.485 Gbps or 1.485/1.001
   Gbps.

   The use of a dedicated serial interconnect is appropriate in a studio
   environment, but it is desirable to leverage the widespread
   availability of high bandwidth IP connectivity to allow efficient
   wide area delivery of SMPTE 292M content.  Accordingly, this memo
   defines an RTP payload format for SMPTE 292M format video.

Gharai, et al.              Standards Track                     [Page 1]
RFC 3497        RTP Payload Format for SMPTE 292M Video       March 2003

   It is to be noted that SMPTE 292M streams have a constant high bit
   rate and are not congestion controlled.  Accordingly, use of this
   payload format should be tightly controlled and limited to private
   networks or those networks that provide resource reservation and
   enhanced quality of service.  This is discussed further in section 9.

   This memo only addresses the transfer of uncompressed HDTV.
   Compressed HDTV is a subset of MPEG-2 [9], which is fully described
   in document A/53 [10] of the Advanced Television Standards Committee.
   The ATSC has also adopted the MPEG-2 transport system (ISO/IEC
   13818-1) [11].  Therefore RFC 2250 [12] sufficiently describes
   transport for compressed HDTV over RTP.

2.  Overview of SMPTE 292M

   A SMPTE 292M television line comprises two interleaved streams, one
   containing the luminance (Y) samples, the other chrominance (CrCb)
   values.  Since chrominance is horizontally sub-sampled (4:2:2 coding)
   the lengths of the two streams match (see Figure 3 of SMPTE 292M
   [1]).  In addition to being the same length the streams also have
   identical structures: each stream is divided into four parts, (figure
   1): (1) start of active video timing reference (SAV); (2) digital
   active line; (3) end of active video timing reference (EAV); and (4)
   digital line blanking.  A SMPTE 292M line may also carry horizontal
   ancillary data (H-ANC) or vertical ancillary data (V-ANC) instead of
   the blanking level; Likewise, ancillary data may be transported
   instead of a digital active line.

   The EAV and SAV are made up of three 10 bit words, with constant
   values of 0x3FF 0x000 0x000 and an additional word (designated as XYZ
   in figure 2), carrying a number of flags.  This includes an F flag
   which designates which field (1 or 2) the line is transporting and
   also a V flag which indicates field blanking.  Table 1, further
   displays the code values in SAV and EAV.  After EAV, are two words,
   LN0 and LN1 (Table 2), that carry the 11 bit line number for the
   SMPTE 292M line.  The Cyclic Redundancy Check, CRC, is also a two
   word value, shown as CR0 and CR1 in figure 2.

      +------------+-----------------------+-----+---------------------+
      |            | Digital Line Blanking |     | Digital Active Line |
      | EAV+LN+CRC | (Blanking level or    | SAV |  (Active Picture or |
      |            |  Ancillary Data)      |     |   Ancillary Data)   |
      +------------+-----------------------+-----+---------------------+

                     Figure 1. The SMPTE 292M line format.
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