Overview of Video On Demand Systems

Joseph Newcomer

SCOPE
INTRODUCTION
THE INITIATIVE FOR WORLDWIDE MULTIMEDIA TELECONFERENCING AND VIDEO
SERVER STANDARDS
NEW BUSINESS IMPERATIVES
STARTING WITH STANDARDS
TWO STANDARDS, ONE GOAL
STANDARDS FIRST
SUMMARY
CONTENT PREPARATION:
REQUIREMENTS:
CODECs/Compression
Object Oriented Database Management Systems
Encoding Verification
SUMMARY
VIDEO SERVER
REQUIREMENTS
LIMITATIONS
PRODUCTS
DISTRIBUTION NETWORK:
LAN TYPES
PROTOCOLS
WAN TYPES

SCOPE

Video on demand has evolved as a major implementation problem for
network integrators. Clients want the ability to retrieve and view stored video
files asynchronously at near broadcast quality, on a local host. Some problems
integrators face to achieve this goal include: video content preparation, server
storage, network throughput, latency, client interfaces, quality of service, and
cost. This paper addresses the design considerations for a private video on
demand implementation.

INTRODUCTION

The Initiative for Worldwide Multimedia Teleconferencing and Video Server
Standards

The market for multipoint multimedia teleconferencing and video server equipment
is poised for explosive growth. The technology for this necessary and much-
anticipated business tool has been in development for years. By the turn of the
century, teleconferences that include any combination of video, audio, data, and
graphics will be standard business practice.

Compliance with teleconferencing standards will create compatible solutions from
competing manufacturers, feeding the market with a variety of products that work
together as smoothly as standard telephone products do today. Specifically, with
the adoption of International Telecommunications Union (ITU) recommendations
T.120, H.320 and H261, multimedia teleconferencing equipment manufacturers,
developers, and service providers will have a basic established connectivity
protocol upon which they can build products, applications, and services that
will change the face of business communications.

New Business Imperatives

Voice on Demand systems are starting to be required by commercial, industrial,
governmental and military associations to retrieve past information in order to
prepare and anticipate future events. This preparation and anticipation can be
crucial to the survival of these industries because of the key roll of the
individuals or groups being monitored. It is this monitoring and collection of
data that allows these organizations to make informed decisions and to take the
appropriate action to current events.

Multipoint multimedia teleconferencing and video servers offer the required
solution. As defined here, it involves a user-specified mix of traditional voice,
motion video, and still-image information in the same session. The images can be
documents, spreadsheets, simple hand-written drawings, highly-detailed color
schematics, photographs or video clips. Participants can access the same image
at the same time, including any changes or comments on that image that are
entered by other participants. Video servers allow users to view stored video
files of specific events, conferences, news clips and important information in
near realtime.

The benefits are obvious. Instead of text interpretation of a video clip, all
interested parties can access the information. Little is left to verbal
interpretation since all users have access to the original video. In the case
of video clips, a persons actions, verbal tones, mannerisms and reactions to
events around them can be viewed and interpreted. Increased productivity,
reduced cost, and reduced travel time are the primary benefits while proprietary
technology and solutions are specified as the primary inhibitors of using video
on demand products and services.

Starting with Standards

While multimedia teleconferencing and video servers promise to revolutionize
vital everyday corporate tasks such as project management, training, and
communication between geographically-dispersed teams, it is clear that
standards-based solutions are a prerequisite for volume deployment. Standards
ensure that end-users are not tied to any one supplier\'s proprietary technology.
They also optimize capital investment in new technologies and prevent the
creation of de facto communication islands, where products manufactured by
different suppliers do not interoperate with each other or do not communicate
over the same type of networks.

When adopted and adhered to by equipment suppliers and service providers alike,
standards represent the most effective and rational market-making mechanism
available. ISDN, fax, X.25, and GSM are a few obvious examples of standards-
based technologies. Without internationally-accepted standards and the
corresponding ability to interoperate, the services based on these technologies
would almost certainly languish as simple curiosities.

Interoperability is particularly important in multipoint operation, where more
than two sites communicate. A proprietary solution might suffice if two end
users want to communicate only with each other; however, this limited type of
communication is rare in today\'s business world. In typical business
communications, multiple sites, multiple networks, and multiple users have
communications equipment from multiple manufacturers, requiring the support of
industry standards to be able to work together. This interoperability is also
critically important when a video server may be transmitting data across a WAN
to multiple users, in multiple sites.

Perhaps the most important effect of standards is that they protect the end
users\' investments. A customer