Browse Prior Art Database

RTP Payload Format of Sun's CellB Video Encoding (RFC2029)

IP.com Disclosure Number: IPCOM000002583D
Original Publication Date: 1996-Oct-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 5 page(s) / 10K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

M. Speer: AUTHOR [+2]

Abstract

This memo describes a packetization scheme for the CellB video encoding. The scheme proposed allows applications to transport CellB video flows over protocols used by RTP. This document is meant for implementors of video applications that want to use RTP and CellB.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 26% of the total text.

Network Working Group M. Speer

Request for Comment: 2029 D. Hoffman

Category: Standards Track Sun Microsystems, Inc.

October 1996

RTP Payload Format of Sun's CellB 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.

Abstract

This memo describes a packetization scheme for the CellB video

encoding. The scheme proposed allows applications to transport CellB

video flows over protocols used by RTP. This document is meant for

implementors of video applications that want to use RTP and CellB.

1. Introduction

The Cell image compression algorithm is a variable bit-rate video

coding scheme. It provides "high" quality, low bit-rate image

compression at low computational cost. The bytestream that is

produced by the Cell encoder consists of instructional codes and

information about the compressed image.

For futher information on Cell compression technology, refer to [1].

Currently, there are two versions of the Cell compression technology:

CellA and CellB. CellA is primarily designed for the encoding of

stored video intended for local display, and will not be discussed in

this memo.

CellB, derived from CellA, has been optimized for network-based video

applications. It is computationally symmetric in both encode and

decode. CellB utilizes a fixed colormap and vector quantization

techniques in the YUV color space to achieve compression.

2. Network Packetization and Encapsulation

2.1 RTP Usage

The RTP timestamp is in units of 90KHz. The same timestamp value is

used for all packet payloads of a frame. The RTP maker bit denotes

the end of a frame.

2.2 CellB Header

The packetization of the CellB bytestream is designed to make the

resulting packet stream robust to packet loss. To achieve this goal,

an additional header is added to each RTP packet to uniquely identify

the location of the first cell of the packet within the current

frame. In addition, the width and height of the frame in pixels is

carried in each CellB packet header. Although the size can only

change between frames, it is carried in every packet to simplify the

packet encoding.

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