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RTP Payload Format for BT.656 Video Encoding (RFC2431) Disclosure Number: IPCOM000003009D
Original Publication Date: 1998-Oct-01
Included in the Prior Art Database: 2019-Feb-11
Document File: 10 page(s) / 14K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Tynan: AUTHOR

Related Documents

10.17487/RFC2431: DOI


This document specifies the RTP payload format for encapsulating ITU Recommendation BT.656-3 video streams in the Real-Time Transport Protocol (RTP). [STANDARDS-TRACK]

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 15% of the total text.

Network Working Group D. Tynan Request for Comments: 2431 Claddagh Films Category: Standards Track October 1998

RTP Payload Format for BT.656 Video Encoding

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 (1998). All Rights Reserved.


This document specifies the RTP payload format for encapsulating ITU Recommendation BT.656-3 video streams in the Real-Time Transport Protocol (RTP). Each RTP packet contains all or a portion of one scan line as defined by ITU Recommendation BT.601-5, and includes fragmentation, decoding and positioning information.

1. Introduction

This document describes a scheme to packetize uncompressed, studio- quality video streams as defined by BT.656 for transport using RTP [1]. A BT.656 video stream is defined by ITU-R Recommendation BT.656-3 [2], as a means of interconnecting digital television equipment operating on the 525-line or 625-line standards, and complying with the 4:2:2 encoding parameters as defined in ITU-R Recommendation BT.601-5 (formerly CCIR-601) [3], Part A.

RTP is defined by the Internet Engineering Task Force (IETF) to provide end-to-end network transport functions suitable for applications transmitting real-time data over multicast or unicast network services. The complete specification of RTP for a particular application requires the RTP protocol document [1], a profile specification document [4], and a payload format specification. This document is intended to serve as the payload format specification for studio-quality video streams.

Tynan Standards Track [Page 1]

RFC 2431 RTP Payload Format for BT.656 October 1998

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 [5].

2. Definitions

For the purposes of this document, the following definitions apply:

Y: An 8-bit or 10-bit coded "luminance" sample. Luminance in this context refers to the BT.601-5 [3] definition which is not the same as a true CIE luminance value. The value of "luminance" refers specifically to video luma. However, in order to avoid confusion with the BT.656 and BT.601 standards, the video luma value is referenced in this document as luminance. Each value has 220 quantization levels with the black level corresponding to level 16 and the peak white level corresponding to 235.

Cb, Cr: An 8-bit or 10-bit coded color-difference sample (as per BT.601-5). Each color-difference value has 225 quantization levels in the centre part of the quantization scale with a color-difference of zero having an encoded value of 128.

True Black: BT.601-...