RTP Payload Format for Society of Motion Picture and Television Engineers (SMPTE) 292M Video
Network Working Group L. Gharai
Request for Comments: 3497 C. Perkins
Category: Standards Track USC/ISI
Bell Labs, Lucent Corporation
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 (C) The Internet Society (2003). All Rights Reserved.
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.
The serial digital interface, SMPTE 292M , 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
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 , which is fully described
in document A/53  of the Advanced Television Standards Committee.
The ATSC has also adopted the MPEG-2 transport system (ISO/IEC
13818-1) . Therefore RFC 2250  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
). 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.
Show full document text