BACK CHANNEL IN INTERACTIVE DIGITAL TELEVISION

SYSTEMS: STRATEGIES FOR PROTOTYPING APPLICATIONS

USING AN INTERACTIVE SERVICE PROVIDER

Internet Computing - Interactive and Multimedia Web Applications

João Benedito dos Santos Junior, João Carlos de Moraes Morselli Junior

Iran Calixto Abrão, Fabiano Costa Teixeira, Gabriel Massote Prado, Paulo Muniz de Ávila

Mateus dos Santos and Rinaldi Fonseca do Nascimento

Pontifical Catholic University of Minas Gerais – PUC Minas, Poços de Caldas – MG, Brazil

TVDILab – Interactive Digital Television Laboratory

Keywords: Interactive Digital Television, Back Channel, IPTV, Mobile Television, Video on Demand.

Abstract: This work, developed at the Interactive Digital Television Lab of the PUC Minas (Brazil), aims to present

strategies for implementation of a prototype of a sufficient platform for building of Interactive Service

Provider (ISP), which can store, analyze and generate reports based on information derived from the

interaction of viewers with applications in Digital Interactive Television, characterized by the use of a back

channel via Internet Protocol (IP). In case of brazilian scenario (Brazilian Digital Television System), the

development of a ISP platform is based-on the experience accumulated with the development of the

platform JiTV (Java Interactive Television), which includes the production in broadcaster enterprise,

transmition over communication network and receiving on access terminal of the viewer, increasing for the

use of back channel to interactivity actions.

1 INTRODUCTION

One of the main innovations that are expected with

the advent of the Digital Interactive Television

(ITV), especially in the context of Brazil, is the

possibility of providing a wide range of new services

and applications (e-commerce, distance education

and the electronic government) with possibility of

interaction of the viewer, offering forms of

interactivity unknown in the analogical television

system (DVB, 2003). However, as a relatively new

technology, with few patterns and research in

progress, the building of applications, services and

systems for ITV still is a challenge, especially for

those who have their business or personal interests

associated to the television system, but do not

dominate technologies and computational tools. In

this sense, it is actually a complex and new universe

for activities such as planning and development,

especially in terms of strategies to be adopted for the

interaction of the viewer.

In this context, this paper presents and discusses

the aspects of implementation of the JiTV platform

(Java Interactive Television), which is under

development since 2002, in the context of research

in the laboratory of the Interactive Digital Television

at PUC Minas (Santos Junior et al, 2007a). The JiTV

platform, through its components and modules of

software, covers the various stages in the lifecycle of

a interactive digital television program (pTVDi),

which starts with the production and distribution of

the data carousel (streams of audio, video and data),

followed by formatting of audio-visual content and

controls of interaction for presentation on the access

terminal of the digital television system (Souza Filho

et al, 2007; Soares et al, 2007); this lifecycle is

finished with the viewer interaction, both at the local

level in the access terminal access and with the use

of a back channel.

130

Benedito dos Santos Junior J., Carlos de Moraes Morselli Junior J., Calixto Abrão I., Costa Teixeira F., Massote Prado G., Muniz de Ávila P., dos Santos

M. and Fonseca do Nascimento R. (2009).

BACK CHANNEL IN INTERACTIVE DIGITAL TELEVISION SYSTEMS: STRATEGIES FOR PROTOTYPING APPLICATIONS USING AN INTERACTIVE

SERVICE PROVIDER - Internet Computing - Interactive and Multimedia Web Applications.

In Proceedings of the 11th International Conference on Enterprise Information Systems - Human-Computer Interaction, pages 130-135

DOI: 10.5220/0002016601300135

 SciTePress

2 ISDTV-T

The project of the Brazilian Digital Television

System (SBTVD) has been started in 2003, through

CPqD actions (agency for managing of the research)

and FINEP (agency for funding of the research), that

decided to offer the national science, through their

universities and research centers, the opportunity to

present solutions of hardware and software to

support the building of a new digital television

system. In mid-2005, the activities of research was

halted by government decision.

The ISDB (Integrated System for Digital

Broadcasting) has been chosen as basic technology

for broadcasting in Brazil. However, in the view of

the needs and specific conditions for the deployment

of digital television in Brazil and is also looking at

the good results obtained from the brazilian research

projects, a hybrid solution was proposed and

accepted by the brazilian government. This solution

includes aspects of transmission and reception with

ISDB technology and software levels/interactivity

(middleware) developed in Brazil (ISDTV, 2006).

This pooling of efforts, resulting in the ISDTV-T

(International Standard for Digital Television

Terrestrial) – the official name of the Brazilian

System for Digital Television.

2.1 Middleware

As mentioned, unlike in other contexts (United

States, Europe and Japan), where digital television

systems have been developed and are in use (DVB,

2003), the conditions for deployment and use of the

system of digital television in Brazil have very

specific characteristics, such as the case of the need

for digital/social inclusion of the brazilian

population.

The features of the software that provides the

display of audio-visual content and control of the

viewer actions (interactivity) must be related to the

specific system. The layers of middleware must

provide resources for hardware and software

components (viewer’s access terminal) operate

together transparent way to the viewer, providing

robust interfaces and simplified use.

In the context of the ISDTV-T, the results of the

brazilian research projects led to the specification of

middleware named Ginga, result of synergy of

researches made with the environments FlexTV

(Souza Filho et al, 2007) - giving rise to the Ginga-J

- and Maestro (Soares et al, 2007) - giving rise to the

Ginga-NCL.

Figure 1: Architecture of the JiTV Platform.

In design of the JiTV platform, development

aspects of the both FlexTV and Maestro

environments have been considered. In further, after

defining the requirements of middleware Ginga for

ISDTV, aspects of implementation have been

considered in the development of the JiTV platform,

allowing the prototyping of scenarios based on

Ginga (ISDTV, 2006), as illustrated in Figure 1.

3 TELEVISION PROGRAMS

The current stage of the development of interactive

television applications, in world-wide level, is

focused on the increasing of some aspects of

interaction to the traditional television programs

(enhanced television) (ATSC, 2001; ISDB, 2001;

DVB, 2002). However, this work proposes a new

model of interactive television program that

considers new interaction criteria as a part of the

program, instead of to add new interaction criteria to

the program (enhanced television).

This kind of architecture is common to the video-

on-demand applications; however, new interaction

criteria are not fundamentally important

(personalization is important).

3.1 Building Interactive Programs

In this proposal, the interactive program is the

central element of an interactive television system.

The interactive program can be defined as the set of

all the medias (and its descriptions), scenes (and its

descriptions), a summary (or synopsis) and its

programming, as showed in the Figure 2.

Initially, the use of profiles allows better

adaptation of interactive programs to the viewer.

ccess Terminal

Operatin

System

(Linux, Windows)

Middleware – Ginga

JiTV Interactive Platform

Resident

App

lications

Non-Resident

Applications

BACK CHANNEL IN INTERACTIVE DIGITAL TELEVISION SYSTEMS: STRATEGIES FOR PROTOTYPING

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131

In this kind of environment, software agents can

provide contextual information to the STB (Set-Top

Box), enhancing the capabilities of the profile. Thus,

the STB can use this information (contextual data),

for the automatic adaptation of the interactive

program to the viewer interests (profile).

4 THE JITV PLATFORM

The current approach to the development of

interactive applications in worldwide provides, in

most cases, the addition of some controls of

interactivity, such as menus and buttons, to the

audio-visual content of the traditional TV. Practices

included in this context have led to applications such

as Enhanced Television, for example. However, with

a similar technological framework it is possible to

develop applications and services with other levels

of interactivity and high level of adaptation to

classes of users/viewers of a digital television

system, such as the ISDTV-T, which has

particularities and specific characteristics in relation

to other international systems (DVB, ATSC, ISDB) .

In this context, one aspect is desirable to subsidize

the developer of pTVDi: the possibility to offer the

same interactive program to viewers with different

interests (profiles) (Santos Junior et al, 2007b).

4.1 The Interactive Program

In designing the platform JiTV, the program

(pTVDi) is the central element of an interactive

application, being composed by the set of all

elements of media (audio, video and images), a

summary (or synopsis) containing the content

television descriptors, bytecodes and information

elements, as showed in the Figure 2.

For the implementation level, the pTVDi is

structured with the use of XML schema, as

encapsulated in two other macro-structures (Santos

Junior et al, 2008a): a) issuing b) programming.

Additionally, external structures also affect the

definition of pTVDi: a) genera catalog of the

program; b) catalog of languages; c) special services

(close caption and translation to LIBRAS – Brazilian

Sign Language, by example). Some details of these

structures can be seen at recent work published

about the JiTV platform (Santos Junior et al, 2008b).

From the media elements, the bytecodes and of

the information available on the synopsis, it is

possible format the multimedia content for the

different viewers, allowing different levels of

interactivity, which is compatible with traditional

Figure 2: pTVDi Components.

proposals related to the Multimedia Home Platform,

as far as presentation of multimedia content (DVB,

2003).

4.2 JiTV Platform

In a Digital Television System, there is a basic

premise: television should not be confused with TV

(televisor). This premise is very relevant in the

context of integration of the media, where

communication networks - cabled and wireless –

terrestrial and satellite, are in full motion of

convergence.

These aspects of convergence allow new modern

arrangements of communication for supporting

Digital Television systems, as is the case IPTV

(Internet Protocol Television), which is, briefly, the

possibility of distribution of television content, and

the resulting interaction with this content, through

communication networks typically organized over

the IP protocol. Furthermore, from the point of view

of the traditional broadcasting businesses, the Digital

Television System must be organized using,

exclusively, a radio-broadcasting on air (terrestrial

and satellite), being explored, also exclusively, by

companies that hold concession for transmission of

television signals.

4.3 Systemic Vision

A draft of a platform for prototyping of television

programs should contain tools that support testing

both in the broadcasting environment as an IPTV

environment. In general lines, the tools of the

platform should allow sufficient shares of authors to

build a pTVDi structure and its distribution to

viewers. Moreover, in terms of the receiver, tools

Programable

Components

Media Descriptors

Information

Elements

Synopsis Bytecodes

Media Elements

Interactive

Program

TVDi

)

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should be available to format the content according

to the access terminal of the viewer (TV, PDA,

personal computer, mobile phones, among others)

and present it in that terminal, allowing the actions

of interactivity previously set in the construction of

pTVDi.

Figure 3: Architecture of the JiTV Platform (production,

distribution, interaction and back channel).

Figure 3 presents the architecture of the JiTV

platform, with focus on the production side and

transmission of pTVDI; a similar architecture exists

on the reception side and interactivity, and is not

reported here for reasons of space (Santos Junior et

al, 2008a).

4.4 Tools and Features

As presented, the JiTV platform consists on a set of

tools to cover the complete lifecycle of a pTVDi.

This lifecycle has its beginning in stages of

construction and formatting of pTVDi, followed by

stage of distribution via the communication

infrastructure (by radio-broadcasting or via IP).

Figure 3 presents a summary of the JiTV from the

viewpoint of a pTVDi author/producer. As a final

step, the data carousel can be transmitted via the

communication infrastructure; for this, the

JiTVStreamer tool manages the tasks of distribution,

as also illustrated in the Figure 3.

The main features of the JiTV Tools can be

viewed as: a) general software platform for fast

application development and integration; b) pre-

integrated with leading middleware applications,

conditional access systems and video servers; c)

open standard interfaces for browser or native

application level development; d) separates software

and hardware for increased product lifetime; e) a

true multi-application for the both IP and STB infra-

structure; f) modular architecture designed for

reliability in operation; g) conditions to scalability in

number of hardware and software models.

As described in section 3.4, the JiTV Platform

can be applied to full lifecycle of a pTVDi. For this

scenario, the platform is composed by: a) JiTV

Application Development Kit (JADK); b) JiTV

Application Suite (JAS).

Figure 4: Interface of the JiTVPlayer showing support for

multi-programming.

In JADK, it is found Support for Java fonts (Sun,

2006), communication support for remote control

using serial and USB ports and bluetooth

connections. Besides that, to manipulate the media

objects, the JADK has the follow resources: a) data

carousel builder (Audio, Video and Data); b) suite

for choosing interactive program mode (mono and

multi-programming); c) metadata for interactive

program structure using XML Schema; d) support

for streaming in several distribution modes (unicast

TV clients, multicast TV clients, broadcast TV

clients). For testing the JiTV features and resources,

are being built two demo applications: 1) the

BlueTV Mono-Programming; 2) the BlueTV Multi-

Programming.

In the JiTV Application Suite (JAS), the main

tools are organized into two modes: a) JiTV Set-Box

Mode; b) JiTV MobileTV Mode. Figure 4 shows the

interface of the multimedia player based on multiple

channels of programming. In an even viewport

display, it is possible to control the presentation of a

JiTV

GCarrossel

Network

JiTV

Studio

pTVDi Data Carroussel

Sinopsys

Data

Application

Bytecode

Data

Descriptors

Audio

Stream(s)

Video

Stream(s)

Image

Stream(s)

JiTV

QuizCompose

JiTV

Streamer

Access Terminal

Back Channel

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channel of audio and recorded video, a channel of

live audio and video, a audio channel, a connection

with a web browser, as well as areas for viewing,

interaction objects and widgets (menus, quiz,

captions, among others).

In Figure 4, there is an interface element for

flagging (upper right of the viewport) which

enables the viewer to select the desired

programming among the four options (multi-

programming) available on the system

5 INTERACTIVE SERVICE

PROVIDER

The back channel is one of the most important parts

of a TVDI system due the fact it is involved with

the revolution of the system as whole. When there is

any viewer's interaction, there is need sending these

information (access level, votes, terminal data,

among others) to the broadcaster's studio, by a

return channel, which is a direct link to data

delivery. Another important factor is that between

the broadcaster and viewer there is another module

called Interactive Service Provider (ISP).

In a typical TVDI system, the treatment of

viewer's interaction can be classified in two ways: a)

the Pseudo-Interactive System (Figure 5a); b) Full-

Interactive System (Figure 5b). In the pseudo-

interactive system, the treatment of interactivity is

processed into access terminal of the viewer and

there is not return of information to the ISP; in this

case, the presence of a back channel is not

mandatory and all applications must be of the kind

resident.

Figure 5a: Architecture for Pseudo-Interactive System.

As shown in the Figures 5a and 5b, the

interactive programs are produced by the

broadcaster station and transmitted via broadcasting

network until to reach the viewer STB. In this point,

for the case of pseudo-interactivity system, the

viewer can interact with applications, but no return

of information for the broadcaster. In other hand, in

a full-interactivity system, information generated by

viewer's interaction can return to broadcaster, using

the infrastructure of the ISP.

Figure 5b: Architecture for Full-Interactive System.

In this research, the JiTVPSI Studio was

developed for supporting all operations between the

follow entities (Figure 5b): 1) broadcaster to

viewer; 2) viewer to ISP and ISP to viewer; 3)

broadcaster to ISP; 4) ISP to broadcaster. For

supporting viewer's operations, the JiTVPSI Studio

provides functionalities for data receiving,

information storing, information sending to ISP.

For supporting broadcaster's operations, JiTVPSI

Studio offers functionalities as to select data filters

on the volume of data which is received from the

viewer's interaction. For validating of the JiTVPSI

Studio under the ISDTV-T test suite, two

applications for full-interactive system have been

developed. The first one, called JiTVDengue, has

been developed for health purposes; the another

application, called JiTVElection, has been

developed for government interests.

The JiTVDengue has been developed in order to

investigate the possibilities of the occurrence of

dengue (a typical disease which occurs in tropical

countries, like is the case of Brazil) into a residence,

allowing to the viewer to interact with the

interactive application in order to answer four

questions concerning the possible cause of dengue.

Soon after the interaction of the viewer, the data are

stored in the STB as a XML structure and sent to

the JiTVPSI Studio, which store these data for use

in government actions. In this context, the JiTVPSI

Studio offers a set of tools for filtering data before

sending reports to the government entities.

Another interactive application - JiTVElection -

has been developed to simulate an majory election

in a city, state or country, allowing to the viewer to

interact with the interactive program in order to

select in which candidate he wants to vote. After

the interaction and confirmation of the vote, the

data for related to the candidate are saved in an

XML file and sent to the JiTVPSI Studio, which

store these information for government interests.

In the broadcaster entity, the JiTVPSI Studio has

as main function to receive data from filtering

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proccess performed in ISP, containing information

stored about the viewer's interactivity. This module

completes the lifecycle of interactivity, which has

its cycle described in the creation of interactive

programs, interaction of the viewer, suite of

software for storing in the ISP.

6 FINAL REMARKS

This work presented aspects of the design and

implementation of strategies for prototyping

applications for interactive digital television system

using an Interactive Service Provider as

infrastructure for back channel. In this scenario, the

JiTV Platform is used for supporting the complete

lifecycle of interactive television digital programs.

As described in the Section 5, are being built two

real applications to demonstrate JiTVPSI Studio

applicability: 1) JiTVDengue (for health purposes);

2) JiTVElection (for government interests). In the

both cases, the JiTV Tools (JAKD and JAS) have

been used by TV producers and viewers. The first

results indicate the versatility of the JiTV Platform

for interactivity operations in the both Broadcasting

and IPTV infra-structures, specially in terms of the

needed infrastructure for supporting back channel

(main focus of this work). Furthermore, a new

business partner (SofTV Enterprise -

www.softv.com.br) has interest on use of JiTV

Tools (JiTV MobileTV Mode) for educational

purposes and applications; for this case, a new

application scenario is under definition and it should

be developed /tested on the next months.

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