MPEG-21 IN BROADCASTING

role in the digital transition of broadcasting

Itaru Kaneko

Tokyo Polytechnic University

Artur Lugmayr, Seppo Kalli

Digital Media Institute, POB. 553, FIN-33101 Tampere, Finland

Abdellatif Benjelloun Touimi

France Telecom R&D, 2 avenue Pierre Marzin - 22307 Lannion, France

Jong-Nam Kim

Korean Broadcasting System (KBS), Korea

Claudio Alberti

EPFL, Swizerland

Sadigurschi Yona

NDS Technologies, Israel

Jaejoon Kim

Daegu University, Korea

Maria Teresa Andrade

INESC Porto, Campus da FEUP, Rua Roberto Frias 378, 4200-465 Porto, Portugal

Keywords: MPEG-21, broadcasting, dig

ital television, metadata, XML

Abstract: The transition to digital in th

e TV broadcasting industry is already gradually being performed while the

complete digital switchover seems now possible to be accomplished within the near future. This article

describes and analyses this phenomenon and the role of MPEG-21 may play in it. MPEG-21 is the ISO/IEC

standard currently under development in MPEG (ISO/IEC JTC1/SC29/WG11). Unlike preceding MPEG

standards - MPEG-21 does not specify a coding format of the content but rather a set of standards to ease

transactions of multimedia content and the provision of digital multimedia services in heterogeneous

network environments, including broadcast. In this paper, we highlight the role of MPEG-21 in broadcasting,

in particular in the deployment of digital TV services.

1 INTRODUCTION

The use of digital technology in TV broadcasting

enables the provision of increased quality and

functionality and will have a major impact on the

viewing behaviour of consumers. We will describe

those major changes and analyze potential problems

and potential usages of MPEG-21 to help

217

Kaneko I., Lugmayr A., Kalli S., Benjelloun Touimi A., Kim J., Alberti C., Yona S., Kim J. and Teresa Andrade M. (2004).

MPEG-21 IN BROADCASTING role in the digital transition of broadcasting.

In Proceedings of the First International Conference on E-Business and Telecommunication Networks, pages 217-222

DOI: 10.5220/0001385802170222

 SciTePress

broadcasting industry to relax such problems.

MPEG-21 specifies a set of standards to ease

transactions of multimedia content and the provision

of digital multimedia services in heterogeneous

network environments, including broadcast. MPEG-

21 is being designed as a common standard for range

of applications of digital multimedia content and one

of most important applications is digital

broadcasting. Various aspects in digital broadcasting

including networking, events, channels, services,

programs, signalling, encoding, bandwidth,

conditional access, subscription, advertisements and

interactivity, are all covered by MPEG-21, placing it

therefore in a position to framework to be applied in

digital broadcasting.

2 DIGITAL TRANSITION IN

BROADCASTING

2.1 Transition in performance and

platform

Currently there is a clear trend in the market towards

wider range of receiver platforms including mobile

platform and higher definition platform. The sales of

personal digital recording are growing very quickly.

This all lead to the rapid replacement of the basic

tool of subscribing broadcasting service.

2.2 Transition in functionality

Change of platform and performance introduces

several new functionalities. Most widely appreciated

function is time-shifting by personal recording

devices. The combination of electronic program and

personal recording derives great enhancement of

viewing opportunity. Networking functionality is not

very widely used currently, but it might have great

impact if broader bandwidth capable to handle video

will be widely available. For the audio broadcasting,

internet is powerful enough to deliver audio

broadcasting and there are over 1000 internet audio

broadcasting station is US and Europe.

2.3 Transition in viewing behaviour

Interactivity can be provided to the TV viewer in

many different ways. There are two main categories

of iTV programming, unrelated or related to the

scheduled programming. The first is referred to as

“24/7” as it comprises interactive services available

all the time. The second, “enhanced services”

includes the provision of alternative camera angles

or feeds during live events, possibility to vote on

contestants in a show or playing with them, but also

additional information related with the normal

programming. These services whilst imposing new

challenges to the TV broadcaster, are already part of

their new business model and are changing the way

viewers behave in front of the TV set. This is being

seen as a personal device, able to satisfy in different

ways their needs, providing them control to decide

the timing and detail to which they watch TV.

3 CHALLANGES FOR MPEG-21 IN

BROADCASTING

3.1 Potential problem

The new digital era in TV broadcasting brought the

multi-channel technology, a considerably larger

number of competing channels combining huge

quantity of archived and new material. TV

broadcasters are seeing themselves confronted with

new challenges and hard competition. In order to be

successful and maintain the loyalty of their audience

or even increase it, broadcasters need to provide

more quality, to offer more choices, to provide

different “flavours” of the same content, to delivery

news fast, to re-distribute content in a differentiated

way, all this across multiple platforms. And in order

to be competitive, they need to do it efficiently

without incurring excessive extra costs.

3.2 Role of MPEG-21

The current workflow in the broadcasting chain is

not adequate to allow re-purposing or re-packaging

the content to support cross-media delivery and

audience-adapted programming. The process is

complicated as it involves many people with

different backgrounds, roles and rights as well as a

large amount of content and metadata coming from

different sources and in different formats. All this

information must be easily accessible to all and its

consistency guaranteed throughout the complete

broadcast workflow. This is where MPEG-21 comes

into play.

4 MPEG-21 OVERVIEW

MPEG-21 is the ISO/IEC standard currently under

development in MPEG (Burnett et al., 2003)

(Bormans, Gelissen and Perkis, 2003). Unlike

preceding MPEG standards, MPEG-21 does not

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focus on the specification of audio-visual

compression formats, but rather on a set of

descriptions to ease transactions of multimedia

content in heterogeneous network environments,

including broadcasting. The standard is currently

divided in 16 parts, from which the ones listed in

Table 1 are considered by the authors as the most

relevant for the work presented in this article.

Table 1: The first seven parts in MPEG-21

Part Title

1 Vision, Technologies and Strategy

2 Digital Item Declaration (DID)

3 Digital Item Identification (DII)

4 Intellectual Property Management and

Protection (IPMP)

5 Rights Expression Language (REL)

6 Rights Data Dictionary (RDD)

7 Digital Item Adaptation (DIA)

The basic concepts of MPEG-21 are the User

and the Digital Item (DI). The User is any type of

content manipulator (e.g. subscriber, producer,

provider, network). The DI corresponds to a

combination of multimedia resources (e.g. MPEG-2

Audio and Video bitstreams) with associated

metadata (e.g. Rights descriptions and/or MPEG-7

Audio and Video descriptors). MPEG-21 builds its

functionality on top of the Digital Item Declaration

(DID, part 2 of the standard), which consists of a

basic model expressed in XML defining the

structure and organisation of DIs. The model

constitutes the foundation to provide higher-level

functionality, enabling identification, description,

handling, monitoring, adaptation and universal usage

of the DI. MPEG-21 tools envisage the provision of

multimedia content and services satisfying the users’

needs and rights in the best possible way given

network, terminal and environment constraints and

in a secure and seamless way. This scope translates

into the well-known concept UMA, the Universal

Multimedia Access. UMA addresses the delivery of

multimedia resources under different and varying

network conditions, diverse terminal equipment

capabilities and user or creator preferences and

needs, while enforcing IPRs and usage rights The

parts of the standard included in Table 1 are the

fundamental vehicles for the effective

implementation of this concept. Digital Rights

Management (DRM) are addressed in parts 4, 5 and

6 - specification of a rights expression language

(part 6 – REL), its corresponding dictionary (part 5 –

RDD) and a DRM architecture allowing

interoperability between the different parts of

MPEG-21 and between different DRM systems (part

4 – IPMP). Eight different DI Adaptation tools are

specified in part 7, each comprising a description

and a resource adaptation engine. These are applied

to the DI in order to seamlessly produce the Adapted

DI to heterogeneous networks and environments,

terminal’s constraints or user preferences (Pereira

and Burnett, 2003) (Perkis et al., 2002) (Fossbakk et

al.,2001). DI Adaptation operations may modify

binary resources or metadata of the input DI or the

declaration of the DI to the usage environment.

5 USE OF MPEG-21 IN

BROADCASTING

MPEG committee acknowledges broadcasting as

one of the most important application of digital

multimedia. Usage scenarios of MPEG-21 in

broadcasting are currently under heavy investigation

incorporated by special ad-hoc group established by

MPEG, named “Ad-hoc group on MPEG-21 in

broadcasting”. The authors of this paper are actively

participating in this activity. This section describes

several of the usage scenarios currently under

investigation.

Figure 1: Digital, Interactive TV value chain

5.1 Digital broadcast item model

(DBIM)

The DBIM represents the model of digital content

for broadcast use (

Figure 1). A typical digital TV

value chain consists of many phases such as

preproduction, production, postproduction and

delivery. The goal is the introduction of a digital

item for broadcasting use – a Digital Broadcast Item

MPEG-21 IN BROADCASTING role in the digital transition of broadcasting

219

(DBI). Each MPEG-21 based DI has an underlying

model describing the behaviour and characteristics

of the item in context. The DBI underlying model is

especially designed for the broadcasting context.

This model is named Digital Broadcast Item Model

(DBIM) (see (Lugmayr et al., 2004)).

The purpose of the DBIM is the harmonization

of several metadata standards as utilized in

broadcasting towards a unified life-cycle and

workflow model. MPEG-21 shall be utilized as

umbrella standard. The DBIM is based on an

MPEG-21 DI especially used in broadcast context

throughout the broadcast value-chain. A DI is used

to communicate between several partners in the

value-chain.

5.2 Interoperable AV clips in

broadcasting

Due to the rapid growth of personal digital recording

and the phenomenon of technology convergence,

interoperable audiovisual clips are being regarded as

one of the most important usage scenarios in

broadcasting. While such clips must be playable on

any existent audiovisual device and medium, the full

exploitation of the service imposes that the rights of

the content owners are adequately managed using

the existing content protection technology.

Concerning increasing new phenomenon in digital

transition, there are also increasing interest for

advanced security models e.g. Multi-Lateral Security

(Kaneko and Shirai 2001) and scalable architecture.

In this context the common representation formats

and the tools to adapt content defined in MPEG-21

parts 4, 5 and 7, may play an essential role and

provide ground for real interoperability among

different DRM technologies. MPEG has been

undertaking great efforts for the standardization of

IPMP mechanisms since 1996, having already

completed the MPEG-2 and MPEG-4 IPMP

specifications. Current work includes the refinement

of requirements for MPEG-21 IPMP and evaluation

of proposals towards the final phase of

standardization. But even if MPEG-21 IPMP is in its

early stages, a closer look at how IPMP works in an

MPEG-4 terminal can be of great help for the

purpose of this paper.

Figure 2 shows a conceptual block diagram of an

MPEG-4 terminal with IPMP Extensions. The

content (left in the figure) contains a data structure

referred to as IPMP Tool List and IPMP Information,

which includes IPMP Tool IDs and Locations. This

information allows terminals to identify and collect

the required IPMP tools that control the access to the

content. Once activated, together with the terminal

elements implementing the IPMP messaging

interfaces, the access to the content is unlocked.

IPM

Tools (T1,T2)

retrieved from the

network

IPMP Tool List

IPMP Information

[ Content ]

Terminal

Video, Audio, etc

Figure 2: MPEG-4/IPMP architecture

5.3 Quality of service management

The management of QoS (Quality of Service)

throughout the broadcasting chain, from content

production to end-user consumption is a real issue in

the broadcasting world. The goal is to achieve the

best possible QoS for the end users taking into

account their expectations as well as the technical

capabilities of the terminal and the resources and

technical parameters of the delivery networks. The

main benefit is the provision of end-to-end control

of the QoS delivered to the end user.

As a specific usage scenario, an end user

receives multimedia content through a broadcasting

infrastructure with some guaranteed QoS. The user

may have different types of terminals (Set-Top-Box,

PC, mobile phone, video-game consoles…) and

access over heterogeneous networks, for example

with multi-channel distribution (DVB-T, DVB-S,

DVB-H, UMTS…).

Several description tools provided by MPEG-21

DIA are useful for this purpose. As example

AdaptationQoS description tools are designed

for the adaptation of the audio and video bitstreams

to match the network constraints, especially

bandwidth. Terminal Capabilities are

description tools designed for the adaptation of the

multimedia content to fit the exact characteristics of

the consuming end-user terminal. Such

characteristics could be the number of speakers,

screen size, etc. Other useful descriptors are the

Network characteristics which are

specified in terms of network capabilities and

conditions, including available bandwidth, delay and

error characteristics.

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5.4 Metadata filtering

Manifold data is present throughout the broadcast

value chain and has manifold representation formats.

The relevant data should be preserved and extracted

semi-automatically for commonly known digital TV

services. Examples are the digital TV program

guide; news broadcast show; informational services

or weather forecasts.

Multi-channel application, thus information to be

published through different information channels

relies on the re-use and transformation of existing

data sources (e.g. teletext content is in parallel

published on a web-page).

The key to realize metadata filtering is the re-use

of metadata, template libraries for services and

computer assisted editing are some examples for

how the process can be made easier. The goal of the

ad-hoc group is to introduce metadata filtering as

basic concept to integrate metadata across systems

(see Figure 3).

Figure 3: Metadata filtering

A very specific example in broadcasting is the

management of service information. Service

information describes the content of television

programs. In principle service information is the

basis for an electronic TV program guide,

commonly known as Electronic Program Guide

(EPG). Service information is organized in many

different tables. The data for these tables needs to be

manually edited, maintained, re-edited and extracted

from multiple sources. This implies a simpler

solution to automatically obtain basic information

for the EPG and prepare it for play-out. Metadata

eXchange Forrmat (MXF) and Advanced Authoring

Format (AAF) files are one potential source for the

basic EPG information. Metadata filtering addresses

the catalysis of metadata from different sources. It

also includes the preparation of metadata for play-

out. The term catalysis addresses several metadata

processes, such as metadata transformation,

conversion of metadata, building the content of

metadata files (e.g. through segmentation, data

mining), validation or visualization.

We can distinguish between creation metadata

and consumer metadata. Creation metadata is

metadata typically used in professional broadcast

systems. Examples are MXF, AAF and the P/Meta

initiative. Consumer metadata convolves several

data structures delivered to consumer networks for

further use. Examples are service information

making up the basic information for the Electronic

Program Guide (EPG), TV-Anytime descriptions

and especially MPEG-21 metadata.

6 CONCLUSIONS

Within the scope of this paper we were able to

present a brief description of the MPEG-21 standard

and its potential applications in broadcasting. A few

important usage scenarios have been described to

illustrate such applications.

Currently, many standardization activities aim at

the convergence of various multimedia services

including the broadcasting environment (Table 2).

Among those activities, MPEG may be obligated in

the harmonization of MPEG application in media

convergence.

Table 2: Standardization activity in media convergence

Organization and activity URL

TV-Anytime Forum http://www.tv-anytime.org/

Pro-MPEG:Material

eXchange Format (MXF)

http://www.mxf.org/

SMPTE: SMPTE 360M

General eXchange Format

(GXF)

http://www.smpte.org/smpte_s

tore/standards/

SMPTE: SMPTE 335M

Metadata Dictionary

http://www.smpte.org/smpte_s

tore/standards/

Pro-MPEG: Advanced

Authoring Format (AAF)

http://www.aafassociation.org/

EBU:P/META (Metadata

Exchange Scheme)

http://www.ebu.ch/department

s/technical/pmc/pmc_meta.ht

IEEE: 1484.12.1 - 2002

Learning Object Metadata

(LOM)

http://ltsc.ieee.org/wg12/

Many any other standards for multimedia asset

management are present in the broadcasting industry.

MXF as well as AAF or P/Meta is especially

designed for post-production, while TV-Anytime

focuses on delivery and consumption. But these

metadata specifications are essentially used within

MPEG-21 IN BROADCASTING role in the digital transition of broadcasting

221

the broadcasting environment. One of the strengths

of MPEG-21 is its potential to act as the vehicle to

bridge the existing gap between the two worlds - that

of the broadcasting world where the distinction

between providers or creators and consumers is

rather clear and that of the Internet where consumers

are simultaneously creators. MPEG-21 can cover or

ensure interoperability with the mentioned metadata

standards either by providing directly the required

functionality and tools, or by including references to

those metadata files and enabling their common use.

And in addition, it is possible to take advantage of

all other value delivered by MPEG-21 such as DRM

interoperability or DI adaptation and QoS awareness.

For example, MXF can be mapped via MPEG -21 to

consumer device readable formats such as TV-

Anytime, DVB-HTML or other relevant XML based

formats. The data contained in MXF structures is

preserved as well the process of mapping can be

automated.

The exploration of the use of MPEG-21 in

broadcasting started with finding MPEG-21’s key

features and strengths. In specific content structuring

as e.g. applied in the LOM is currently only

available in production phases due to proprietary

standards (e.g. MXF). MPEG-21 can be specifically

applied in delivery phases and can be seen as

middleware standard for advanced consumer device

architectures. Intelligent middleware architectures

matching low-level resources to high-level demands

from application side are strongly supported by

MPEG-21 and its adaptation and QoS features.

MPEG-21 provides therefore an excellent

solution for solving issues such as QoS management,

IPMP or adaptation in an excellent way and MPEG-

21 already covers much other important area.

Work is continuing to provide firm ground for

the broadcasting industry in digital switchover. In

the near future we will be able to report about more

advanced usage scenarios and their technical

challenges.

ACKNOWLEDGEMENTS

We would like to thank members of MPEG, in

particular to those participating in the “ad-hoc group

on MPEG-21 in broadcasting”. Without their effort,

this article would not have been possible to be

authored.

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Bormans, J., Gelissen, J., and Perkis, A. (2003). MPEG-

21: The 21st Century Multimedia Framework. IEEE

Signal Processing Magazine, March 2003, Vol. 20, No.

Pereira, F., and Burnett, I. (2003). Universal Multimedia

Experiences for Tomorrow. IEEE Signal Processing

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Perkis, A. et al. (2002). A Streaming Media Engine Using

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