ArviD-publications 02/2004
A Guide for Digital TV
Service Producers
Digital television cluster programme
ArviD-publications 02/2004
A Guide for Digital TV
Service Producers
ISBN 952-201-001-4
ArviD-publications
Helsinki 2004
The publisher DESCRIPTION
Date of publication
22.04.2004
Authors (from body, name, chairman and secretary of the Type of publication
body)
Guide
Mikael Rinnetmäki, Sofia Digital Oy.
Assigned by
Project steering group: Marko Heikkinen, Tekes;
Ismo Kosonen and Marjukka Saarijärvi, MTC; Ari Ministry of Transport and Communications
Pöyhtäri, Sofia Digital Oy.; Pekka Nykänen and Date when body appointed
Arto Saikanmäki, JP-Epstar Oy 16.12.2003
Name of the publication
A Guide for Digital TV Service Producers
Abstract
On March 4 2004 the Finnish Government made a policy decision according to which television broadcasts
will become digital in Finland from August 31 2007 onwards.
Ministry of Transport and Communications Finland (MTC) and The National Technology Agency of
Finland (Tekes) have ordered and funded this guide to promote the production and use of easy-to-use and
innovative digital TV content. The guide targets content producers and designers as well as other people in-
terested in creating interactive digital TV services. The guide introduces the basic features of digital televi-
sion and the design principles for digital television services.
As digital television services are going through an intensive development period, the maintenance of up-to-
date information in each topic area requires a short updating cycle. This is why alongside publishing the
guide at the ArviD program website (http://www.arvid.tv/) an updating section will be maintained.
Keywords
digital television, services, content, interactivity, ease-of-use
Miscellaneous
Serial Name and number ISBN
ArviD publications 02/2004 952-201-001-4
Pages, total Language Price Confidence status
71 English Public
Distributed by Published by
JP-Epstar Oy / Jaakko Pöyry Infra Ministry of Transport and Communications
Prologue
On March 4 2004 the Finnish Government made a policy decision according to which
television broadcasts will become digital in Finland from August 31 2007 onwards. The
Ministry of Transport and Communications Finland and Tekes (The National Technol-
ogy Agency of Finland) have ordered and funded this guide to promote the production
and use of easy-to-use and innovative digital TV content. In a TV environment targeted
at a wide audience the requirements for ease-of-use of applications should be empha-
sized. Compared to the PC world, television has its own special features which make
the development of the services challenging and interesting. The newest and most im-
portant information about digital TV has been gathered in this guide to be used by ser-
vice builders and other people interested in the subject.
The guide has been written by Software Development Manager Mikael Rinnetmäki
from Sofia Digital Oy. The work has been guided by a support group consisting of
Chief Technology Adviser Marko Heikkinen from Tekes, Counsellor of Communica-
tions Ismo Kosonen and Ministerial Adviser Marjukka Saarijärvi from the Ministry of
Transport and Communications Finland, Director Ari Pöyhtäri from Sofia Digital Oy,
Program Coordinator Pekka Nykänen and Consultant Arto Saikanmäki from JP-Epstar
Oy. The content of the guide has been commented on by the Finnish Broadcasting
Company, Tieke ry (Finnish Information Society Development Centre), Ortikon Inter-
active Oy, Suomen 3KTV Oy and Vaasan Läänin Puhelin Oy. The guide has been trans-
lated by Technical Writer Heidi Lehtinen from Sofia Digital Oy.
This guide is the first publication of the ArviD cluster program of the Ministry of
Transport and Communications Finland started in April 2004. Let’s work together to
make digital television a good channel for entertainment, information, participation,
learning and business for all Finns.
April 2004, Helsinki
Marjukka Saarijärvi
iii
Terminology and Abbreviations Used
Aspect ratio Aspect ratio is the ratio of the width and height of a TV
picture. Traditionally, the aspect ratio has been 4:3, but
with digital television a more movie-like aspect ratio 16:9
is becoming popular.
Digital TV service An application or a content entity transmitted on a digital
TV network.
Dithering A method for showing the colors in a bitmap image with a
smaller number of colors by forming the desired tones
from the adjacent pixels of different color.
DVB-HTML Part of the MHP specification which defines the XHTML-
based browser for MHP receivers and a markup language
for implementing MHP services.
Electronic program guide EPG. An application that shows information about upcom-
ing programs. Digital TV receivers usually have a built-in
program guide. See also Program Guide.
I-Frame A still image of an MPEG2 video. An I-Frame can be
shown in full color in the background of each MHP re-
ceiver even if the graphics device of the receivers other-
wise supports only a smaller color space.
Interactive application An MHP application which the viewer can interact with
by using a remote control for example.
MHP specification The Multimedia Home Platform specification defines an
open Application Programming Interface (API) for appli-
cations executed on digital TV receivers. The ETSI stan-
dard DVB-MHP is based on this specification.
Multiplex Multiplex is an MPEG2 program stream that can contain,
among other things, several TV and radio channels and in-
teractive services. The capacity of a multiplex depends on
the parameters used. In Finland, the capacity of a terres-
trial multiplex is about 22 Mbit/s which can contain about
4-5 TV channels with additional MHP services.
Network operator The holder of a network license who has been granted the
right of use of frequencies on the network. In practice, the
party in charge of supplying digital TV content to the
viewers.
iv
NorDig A cooperative organization consisting of Nordic television
and telecom companies that defines the Nordic classifica-
tion for digital TV receivers. http://www.nordig.org/.
Object carousel A method or system for sending applications and the files
they need together with the digital TV signal.
PNG An image format which enables the definition of translu-
cency for bitmap images.
Program Guide Program Guide used by the Finnish national main chan-
nels is an EPG MHP application transmitted with the TV
signal.
Program license holder A party with the right to regularly broadcast TV and radio
contents on the digital TV network.
Return channel A method or system for the viewer to send data to the ser-
vice provider or to search for more personalized, for in-
stance dynamically created, content.
Superteletext Superteksti-TV. A service platform based on an MHP ap-
plication which enables content-based services to be easily
provided. Superteletext is in use on the channels of the
biggest program license holders.
Usability Usability means the pleasantness of the use of a service for
the end user. Usability mostly consists of ease of use and
experiencing the use of an application as a real-life situa-
tion. Usability is achieved by user-centered design.
v
Contents
Prologue ...........................................................................................................................iii
Terminology and Abbreviations Used .............................................................................iv
Contents ...........................................................................................................................vi
1 Introduction............................................................................................................... 1
1.1 Background to the Guide and the Readers........................................................ 1
1.2 The Scope of the Guide..................................................................................... 1
2 Digital Television in Finland in 2004 ....................................................................... 2
2.1 Digital TV Operators ........................................................................................ 2
Program license holders............................................................................................ 2
Network operators..................................................................................................... 3
2.2 Receivers........................................................................................................... 3
2.3 MHP .................................................................................................................. 4
Additional regional specifications ............................................................................ 6
2.4 Software Updates .............................................................................................. 6
2.5 Digital TV Applications.................................................................................... 7
3 TV as an Application Environment ........................................................................ 10
3.1 Special Features of Television ........................................................................ 10
Cursor...................................................................................................................... 11
3.2 Usability .......................................................................................................... 12
3.3 User ................................................................................................................. 12
Find out the target group of the service .................................................................. 13
3.4 Use Situation ................................................................................................... 13
Remember the alertness of the viewer .................................................................... 13
Give everyone a chance to participate – or not to participate................................. 14
3.5 Interaction ....................................................................................................... 14
Use natural dialog ................................................................................................... 14
Support laziness and learning ................................................................................. 15
Give immediate feedback ....................................................................................... 16
Decide the roles for the remote control buttons...................................................... 16
Support different possibilities in text input............................................................. 17
vi
Be consistent ...........................................................................................................18
3.6 Instructions......................................................................................................19
Format the instructions according to the viewer’s need .........................................19
3.7 Usability Testing .............................................................................................20
Define the goals and the indicators .........................................................................20
Choose the correct method......................................................................................21
4 Properties of the MHP.............................................................................................23
4.1 The MHP Application .....................................................................................23
4.2 The Life Span of an Application.....................................................................23
Release resources in the paused state......................................................................23
4.3 File System......................................................................................................24
4.4 Return Channel................................................................................................24
4.5 Persistent Storage ............................................................................................25
4.6 Support for Smart Cards .................................................................................25
4.7 Drawing Layers...............................................................................................26
4.8 Resolution .......................................................................................................27
Avoid thin lines.......................................................................................................27
4.9 Colors ..............................................................................................................28
Avoid bright colors .................................................................................................28
Use brightness contrast ...........................................................................................29
4.10 Vector Graphics ..............................................................................................29
4.11 Pictures............................................................................................................29
Optimize the file size of the pictures ......................................................................30
4.12 Animation........................................................................................................30
4.13 User Interface Components.............................................................................30
4.14 Fonts................................................................................................................31
Use sans-serif fonts .................................................................................................32
4.15 Sounds .............................................................................................................33
Let the sound of the TV program be audible in the background ............................33
Pay attention to the size of the sound files..............................................................33
4.16 Video ...............................................................................................................33
Use TV picture with consideration .........................................................................34
4.17 Remote control ................................................................................................35
Visualize the color buttons as a group ....................................................................36
4.18 Data Security and Data Protection ..................................................................36
5 Superteletext............................................................................................................37
5.1 Superteletext Features .....................................................................................38
vii
Markup language .................................................................................................... 38
Browsing ................................................................................................................. 39
Links ....................................................................................................................... 40
Number buttons....................................................................................................... 40
Color button menus................................................................................................. 41
Return channel ........................................................................................................ 41
5.2 Content Production Process ............................................................................ 41
Define the size of the content.................................................................................. 41
Think through the need for updating ...................................................................... 42
Build a path for browsable content ......................................................................... 42
Make the search faster with a hierarchy ................................................................. 43
Combine navigation methods carefully .................................................................. 44
List the links one below the other ........................................................................... 44
Separate the content and layout .............................................................................. 45
5.3 Tools for Content Production.......................................................................... 45
6 Application Development ....................................................................................... 47
6.1 Testing............................................................................................................. 49
7 Adapting Finished Services to Digital TV.............................................................. 50
8 Distributing a Service.............................................................................................. 54
8.1 Superteletext Contents .................................................................................... 54
8.2 Service Menus................................................................................................. 55
8.3 Own Service Channel...................................................................................... 57
8.4 Terrestrial Distribution.................................................................................... 57
8.5 Cable Distribution ........................................................................................... 57
Sources ............................................................................................................................ 58
Portals and Link Lists ................................................................................................. 58
Reports and Publications............................................................................................. 58
Usability ...................................................................................................................... 58
Organizations and specifications ................................................................................ 59
Companies................................................................................................................... 60
Figures............................................................................................................................. 62
viii
1 Introduction
1.1 Background to the Guide and the Readers
The ArviD digital TV cluster program of the Ministry of Transport and Communica-
tions Finland and Tekes (The National Technology Agency of Finland) have jointly
funded this update of the Digi-TV:n palveluntarjoajan opas (A Guide for the Digital TV
Service Provider) written in 2001 as part of the USIX program of Tekes. In addition to
updating the guide, examples are provided of, among others, the first interactive MHP
applications.
The guide targets content producers and designers as well as other people interested in
creating interactive digital TV services. The guide introduces the basic features of digi-
tal television and the design principles for digital television services. The sources used
and recommended links for further reading can be found at the end of the guide.
1.2 The Scope of the Guide
With regard to DVB-HTML browsers, the guide mostly focuses on the Superteletext
platform used on digital terrestrial network by the Finnish Broadcasting Company
(YLE), MTV Group and Ruutunelonen. The reason for this is that when writing the
guide (in January and February 2004) other TV channels and cable operators had not
yet made any decisions concerning the aforementioned platform.
As digital television services are going through an intensive development period, the
maintenance of up-to-date information in each topic area requires a short updating cy-
cle. This is why alongside publishing the guide at the ArviD program website
(http://www.arvid.tv/) an updating section will be maintained. All current information
regarding service distribution will be provided at this website in addition to information
concerning the production of digital TV services.
1
2 Digital Television in Finland in 2004
2.1 Digital TV Operators
In Finland, digital television operation is divided into two parts. The program license
holders are in charge of program content; network operators, on the other hand, are re-
sponsible for the technical delivery to the viewers.
Program license holders
In the Finnish digital television there are several program license holders. Some of the
licenses are nationwide, some are local. When granting the licenses, the intention has
been to create a viable environment with several different services.
In addition to the digital versions of two analog channels, the Finnish Broadcasting
Company (YLE) offers three new TV channels on the digital side: YLE24 focuses on
news, FST on Swedish-language content and YLE Teema on culture, education and sci-
ence. In addition, YLE also broadcasts four radio channels on the digital TV network.
MTV Group’s MTV3 and Ruutunelonen’s Channel Four Finland are digital versions of
analog channels. Both also have supplemental channels MTV+ and Nelonen Plus which
offer programs less frequently.
New channels are The Finnish Sports Channel and a youth channel SubTV by SubTV
Oy. Both of these can also be seen on analog cable broadcast quite widely. Canal+
Finland Oy offers three subscription channels for movies, sports and TV series. The
shopping channel Viisi by Vizor Oy is a 24/7 shopping and lifestyle channel.
In addition to the licenses presented above, two other regional program licenses have
been granted: to Janton Plc in the Helsinki metropolitan area and in Pirkanmaa and to
Turun Kaapelitelevisio in the Turku region.
In December 2003 more regional TV program licenses and a national radio program
license for four radio channels were granted.
No program license is needed to broadcast only interactive applications or one-off pro-
grams. A short-term license is needed when the weekly duration of the programs is four
hours or more or when the total duration of broadcasting is less than three months. A
short-term license can be applied for from the Finnish Communications Regulatory Au-
thority (FICORA), and it is usually granted if the program content is in accordance with
Finnish law.
2
Network operators
One half of Finnish households receive their TV signal through a terrestrial antenna
network, the other half through a cable network.
Digita has been granted a network license for the digital terrestrial network regarding
three multiplexes. Geographically, there are already over 70 % of Finns in the digital
TV network coverage area. By September 2004, the coverage will be as much as 94 %
with regard to the multiplexes A and B while the multiplex C will remain in the 72 %
coverage area at least for now.
There are several regionally operating cable operators in Finland. The cable operators
transmit the TV programs of the holders of the terrestrial program license as well as dif-
ferent channels some of which are packed into subscription channel packages.
On the cable television side there are several cable operators. The largest distribution
network is Suomen 3KTV Oy, part of the Finnet group. There are 280,000 households
connected to the networks of Suomen 3KTV. 250,000 households are connected to the
network of HTV operating in the Helsinki metropolitan area and 150,000 households to
the networks of Tampereen tietoverkko (in Tampere, Jyväskylä, Joensuu and Uusimaa).
TeliaSonera has 70 cable TV networks all around Finland covering approximately
150,000 households. On the network of Turun kaapelitelevisio in the Turku region and
on the networks of Vaasan Läänin Puhelin in Pietarsaari and Kokkola there are about
80,000 households on each.
The third method of distributing TV signal, satellite distribution, reaches only 5 per cent
of the Finnish population. Satellite reception is typically an addition to some other type
of reception in Finnish households.
2.2 Receivers
An MHP receiver is needed to use interactive digital TV applications. The receiver is
most often a separate digital set-top box attached to the television (STB), but it might
also be a television with a built-in digital TV receiver and MHP capabilities (iDTV) or a
digital TV receiver board on a computer. At the moment, only a small number of digital
TV receivers are MHP devices.
The devices of different manufacturers differ from each other with regard to their prop-
erties and capacity. There are differences in the amount of memory, the graphics capa-
bilities and the processing speed. The internal user interfaces of the receivers and the
remote controls are also different. The MHP specification includes certain minimum
requirements which every MHP device must meet.
The performance of the first generation receivers can more or less be compared to the
first computers with a Pentium processor with regard to computing power. Of course,
there are big differences between the receivers. It also should be noted that the program
code of the MHP services run on the receivers is Java which needs to be separately in-
terpreted with a virtual processor, and hence it is significantly less efficient than native
code which can directly access the operating system.
3
There are typically 16 or 32 megabytes of memory on the devices. A big proportion of
this goes to the use of the operating system. The amount of memory available for an ap-
plication is dependent on other applications and their signaling as well as on the cache
memory of the receiver. There will be problems with the first generation MHP receivers
if one separate application requires more than one or two megabytes of memory. Other
simultaneously running applications also have to be taken into account when estimating
the sufficiency of memory.
Receivers naturally have chips especially optimized for processing television picture.
When this guide was being written, no digital TV receiver board with MHP properties
was available for a computer but anyone interested in the matter can follow the
MHP4Free project (http://www.mhp4free.de/).
2.3 MHP
MHP, Multimedia Home Platform, is a specification with which interactive digital TV
services are implemented. It is an open interface designed by the DVB organization, and
it defines what features MHP devices have and how applications can use those features.
Application 1 Application 2
MHP API
THE OPERATING SYSTEM OF THE RECEIVER
File system
Return channel Graphics
Figure 1. The MHP functions as a mid-layer with which applica-
tions can use the functions of any MHP device in the same way.
MHP applications are based on the Java programming language with some extensions
specific to TV domain and on features added to it which emphasize the distinctions of
the television environment. An MHP receiver downloads the files needed to execute an
application from the broadcast stream and executes the application with the java virtual
machine. The application uses the features of the device with interfaces described in the
MHP specification.
The MHP specification also includes the specification of the markup language, DVB-
HTML. With the help of the markup language, the implementation of simple content-
based services is significantly easier than by programming with the Java language.
4
DVB-HTML defines a universal built-in browser for MHP devices and its interfaces for
TV properties and Java applications. DVB-HTML is a modularization of the XHTML
language for the TV environment including interfaces for communicating with Java-
language MHP applications.
DVB-HTML is a language implemented in XML which is why it differs on some points
from the traditional HTML language used on the web. Generally, content described
with the XHTML language needs to be more carefully defined compared to HTML con-
tent.
Application 1 Application 2 Application 3
MHP API DVB-HTML
THE OPERATING SYSTEM OF THE RECEIVER
File system
Return channel Graphics
Figure 2. Version 1.1 of the MHP specification defines the DVB-
HTML markup language and the DVB-HTML browser which can op-
tionally be added to receivers.
However, the DVB-HTML support is not part of the specification of the first generation
MHP devices, and it is therefore not implemented on any receiver on the market at the
moment. Receivers that support the DVB-HTML specification are also not expected to
enter the market in the near future. Instead, there are separate MHP applications on the
market which implement a small subset of the DVB-HTML markup language and thus
allow the content producers to use the advantages of content-based service production.
One example of such services is the Superteletext application.
The current 1.0.2 version of the MHP includes support for encrypted channels and the
return channel (internet connection). The internet connection does not mean that the re-
ceivers have a web browser or an email, but the application can communicate with serv-
ers on the internet through this connection.
All functions in the MHP specification did not yet function in the receivers when this
guide was being written. Tests have not been developed for all features in the MHP con-
formance test suite yet. Due to this, some features may function differently on different
receivers or some functions may be missing. Version 1.0.3 of the test suite is meant to
be considerably more extensive. It has been estimated that it will be ready at the end of
2004. Chapter 4. Properties of the MHP deals with the features of the specification in
more detail.
5
Version 1.1 of the specification includes a more extensive support for smart cards, and
the possibility to download applications through the return channel and save them in
persistent storage. The subsequent versions further along in the future will add the sup-
port for hard disk recorders and for TV broadcast reception through an internet connec-
tion.
No estimate can be made of the time when new versions will be on the market. It may
be that the receivers take in parts from the later versions of the specification gradually
and according to need; for example, the MHP devices sold in Italy at the moment al-
ready have the more extensive OCF smart card support of version 1.1.
Additional regional specifications
Several regional organizations have tried to detail the MHP specification in certain
market areas to guarantee an adequate universal service level for the consumers in the
area. Examples of such additional specifications are the Nordic NorDig
(http://www.nordig.org/), F.U.N. (Free Universe Network, http://www.fun-tv.de/) in the
German-language market and the Italian DGTV (http://www.dgtvi.net/).
The goal of the device manufacturers is, however, to sell their devices on a wider mar-
ket, and the features of the devices are defined according to the market analyses of the
manufacturers. The manufacturers believe that MHP compatibility is an adequate guar-
antee that the services will function.
2.4 Software Updates
The operating system of MHP receivers can be updated automatically with the software
update in the TV signal. This way, new features can be added to the devices when the
MHP standard evolves, and the owner of the device does not have to take the device to
be serviced or to carry out complicated updating procedures.
Some of the new features of the MHP standard require changes in the hardware of the
receivers. One of these changes is adding a hard disk for program recording. It is not
possible to add these features to existing devices with a software update, but to be able
to use those features the viewer has to purchase a newer MHP receiver.
The frequency of software updates depends on the manufacturer of the device. The
usual updating frequency is one to four times a year.
Software updates also affect digital TV applications. The MHP standard develops fast,
especially at the beginning, and changes may occur in features that have already been
defined. In reality, the application has to be tested with the new software version after
each software update to make sure that it still functions appropriately.
6
2.5 Digital TV Applications
In this guide digital TV applications mean MHP applications transmitted along with the
TV signal. These services can be either independent or closely connected to the topic or
progress of a TV program.
Figure 3. Program Guide shows information about the current
and upcoming programs.
Examples of typical independent applications are Program Guide and service menus,
Superteletext and, for instance, banking services. An example of an application con-
nected to a program would be MTV3’s Hockey Night application which during a
hockey match offers results from other matches in that round, statistics and the possibil-
ity to capture images from the TV broadcast and to send them as an MMS messages to a
mobile phone.
Digital TV receivers may themselves have some built-in applications such as an EPG
which shows program information or an application list operating the MHP applica-
tions. However, these are different on each receiver, and their functions are usually
more limited than those of MHP applications.
7
Figure 4. The MTV3 service menu shows all available interactive
services.
Figure 5. The front page of the MTV3 Superteletext.
8
Figure 6. The memory game on YLE Teema is an independent
application which is not connected to any TV program.
Figure 7. The Nokia MHP receiver has built-in games.
9
3 TV as an Application Environment
Most of the programmed applications are implemented in a PC environment. This sec-
tion mostly deals with the differences between a PC and a TV. More information about
the differences can be found at http://www.ergogero.com/pages/digitaltv.html.
In a TV environment the requirements for the ease of use of an application are empha-
sized. TV is a medium for a larger audience than a PC and is used for entertainment.
In the PC environment, the usability of applications has already been studied. There are
recommendations and established methods of use regarding the structure of the user in-
terface, the positioning of the elements, naming conventions and colors. In the TV envi-
ronment no models have yet been established.
The know-how of experts of several fields is needed in implementing TV user inter-
faces. Graphic designers working with TV graphics know what type of graphics suit
television; web graphic designers, on the other hand, know how images can be com-
pressed to a smaller file size. Expert help is also available for usability design and us-
ability testing.
3.1 Special Features of Television
Although a TV screen is usually larger than a computer monitor, the viewing distance is
also greater and the resolution poorer, which is why much less information fits on one
television view than with computer applications, e.g. only about twenty lines of text fit
on one view.
In a TV application, a longer view should be divided into separate views. Scrollable
views are not recommended.
The way TV is used does not support direct manipulation in user interfaces similar to
PC use. No freely movable mouse cursor is available for moving or editing objects on
the screen.
The designing of TV applications should, therefore, rather be approached from the point
of view of mobile applications. With phone applications, as well as on TV, the use is
based on arrow buttons, selection and number buttons. The content of analog teletext
can be considered an example when designing content divided into several views.
In a PC user interface, it is essential to visualize which user interface component can be
activated or edited. In TV applications, on the other hand, it is essential to explain
which buttons on the remote control can be used and their corresponding functions. In-
teractive applications also have to stand out from other possible graphics on the screen
during a TV broadcast.
10
Cursor
Unlike the computer environment, the MHP does not offer a ready-made cursor for ap-
plications.
The most often used cursor type in television applications is a yellow-toned frame.
When using this type of cursor, it should be made sure that there are no yellow lines or
frames in the content of the page. It should be clear to the viewer from the first glance
which visible elements are part of the background and content and which is the cursor
that the viewer can move. The cursor should stand out clearly from the background, as
though it floated over the page. This helps the viewer to realize that it can be moved.
The mobility of the cursor can be illustrated with small arrows close to its borders. This
way it is better associated with the arrow button group on the remote control. There can
also be a symbol of the OK button with the cursor to make it clear to the viewer how the
selection is made.
Figure 8. Different types of cursors in digital TV services.
When thinking about the color of the cursor, one has to take into consideration the color
buttons. If the tones of the yellow color button symbol and the cursor are similar, the
viewer may wrongly associate their uses.
When thinking about the appearance of the cursor, one should consider a situation in
which there are two choices on the selection menu. Then the viewer does not necessar-
ily know which option is active if, for instance, only the text color and background
change.
However, not all navigation methods are based on a movable cursor. For example, when
browsing the Finnish national Program Guide, the cursor never moves, it is the
browsable content, such as the channels, that move.
11
3.2 Usability
In this guide the word usability refers to the feature of an application which makes it
easy and good to use and which produces a good use experience. Good usability is
achieved by user-centered design.
Contrary to common belief, usability is to a large extent a quality that can be measured.
Different indicators are, among others, efficiency, flawlessness and user satisfaction.
Effectiveness can be measured by observing how fast and with how few actions the user
finishes the task given. The use is flawless if the user behaves the way the designer had
intended on each occasion. An important indicator is the users’ subjective satisfaction;
for them a less efficient method may still be the most pleasant one.
As regards interactive television, two factors are emphasized: ease of use and enter-
tainment. Of these two, ease of use is clearly a priority at least in the beginning. People
are not used to use a television in any way other than by changing the channel, and no
other familiar ways have been established yet. This is why the first applications in inter-
active television should be very clear, and the use should be as intuitive as possible. The
user needs to be told very clearly what it is possible to do with the application and how
this can be done.
People are used to be entertained by television, and this should also be possible with
interactive television. An application that seems to be too simple may be considered
boring, uninteresting, and too business-like. This is why special attention also has to be
focused on the pleasant appearance of the application and on making the use seem as
real as possible compared to doing the same thing in its natural environment (experienc-
ing, as in banking services and banks). In some applications the element of surprise has
to be taken into consideration as well.
Experiencing is supported by a user interface which offers the user an experience of the
environment and of participating. The user interface can entice the user to try out differ-
ent options and features instead of merely presenting them.
3.3 User
Building usability always begins with identifying the user. The designer has to identify
the target group, their needs and goals and the most frequent use situations.
An uncontested majority of the Western population are television viewers. The group
contains all age groups and all social classes, people’s different life situations, emotions,
attitudes, hopes and needs. The user of digital television may be anyone.
The users of digital TV services are a more varied group than the users of PC applica-
tions. PC users are normally educated people of working age whereas all people from
children to pensioners watch television.
The methods of using TV are also diverse. People enjoy themselves in front of a televi-
sion; they watch it in groups, can be tired or sick. An application may invite the viewer
to participate and change the viewing experience, but it is certain that passive viewing
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of television will continue. In order for this to remain in mind, this guide mostly refers
to the user as the viewer.
Accessibility and availability are still problematic areas in digital TV. There is no
counter-part for TV browsers, such as Superteletext, which would provide an oral pres-
entation of the content instead of text.
Find out the target group of the service
Every service has its own primary target group. The characteristics of this group have to
be kept in mind when designing a service. The attitude of a Nintendo youngster who has
grown up with game consoles towards the services which television offers is different
from that of the older generation. The vocabulary used and the appearance of the service
as a whole have to be designed according to the target group.
In practice, the viewer’s history with computers and information technology greatly af-
fects the way they see the service, the possibilities it offers and its most common uses.
Assumption of the knowledge and know-how that the viewers have can be helpful when
designing modes of operation. For example, people who have used mobile phones a lot
and mobile services will also understand the models of interaction familiar from mobile
phones in the television environment. With services that are aimed at the younger popu-
lation, it is possible, for instance, to compromise a little the readability requirements by
using a smaller font.
The possible interpretations of language and symbols within the target groups are often
strongly associated with usability. Finland can mostly be regarded as a one-culture
country with respect to symbols; pictorial symbols are usually interpreted similarly
within each population group. However, with regard to cultural differences in Finland, it
is good to keep in mind at least the Swedish-speaking minority.
3.4 Use Situation
Television is rarely used. People mostly stay and enjoy themselves watching it Remem-
ber the alertness of the viewer.
Remember the alertness of the viewer
It is important to take the viewer’s state of alertness into consideration. When using
television services, the viewer may be extremely tired or in an emotional state of mind.
It is often a matter of relaxation, but the state of alertness may also be higher than in the
optimum situation if the viewer puts her heart and soul into sports, for instance. Con-
centration suffers as much in an excited state of mind as it does in a sleepy one. This
requires an extremely easy and clear user interface from television applications.
It is also good to remember the focus of the user’s attention in a use situation. The main
focus is usually on the television program enriched by an interactive application, but the
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remote control also needs a focus of its own. This is why the use should be based on the
most commonly used buttons and button combinations that the viewer can find intui-
tively.
Give everyone a chance to participate – or not to participate
There is often more than one person in front of a TV screen. Applications should, there-
fore, support group participation where possible. If the application asks for the age or
horoscope of the respondent at some point and gives the response according to the an-
swer, it is polite to allow the information to be input several times in order for everyone
to have the possibility to participate. It also is important for many people who enjoy
playing games to be able to save the best results under their own name and compare
them to those of others.
A situation where the viewer does not want to participate has to be taken into considera-
tion as well. The television is often merely an extra amusement alongside other tasks.
The viewer may, for example, glance at a quiz show on television while doing house
chores.
Therefore, is it useful to offer the viewer the possibility to answer the questions, but in-
teractivity should not be required. The application should move forward with the pro-
gram even if it is obvious that the viewer is not interested in participating in the interac-
tivity.
3.5 Interaction
The most essential part of interactivity is that the participants understand each other. It
is important for the application to correctly interpret the messages of the viewer and to
shape its own output into an understandable form.
Use natural dialog
The application should be understandable to the viewer as a whole. It should be clear at
the first glance what it is meant for, what it is possible to do with it and how it is possi-
ble to do something.
Interactivity should advance on the viewer’s terms and at least to some extent according
to the models of human or otherwise known interaction. If an application, for instance,
collects information about the viewer, it is good to collect the information in the usual
order – the usual list: name, address, postal code and postal area – and not in the order
in which the application happens to need it.
In order for the use to be easy and for it also to be possible while watching television no
remembering should be required of the user. All actions should be clearly in view and
ready to be used or at least easy to find in each situation with visible references.
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Too much information or options should not be placed on one view. People perceive
five to nine choices on one view, depending on the individual and the situation. Consid-
ering the diversity of the viewers and the use situation, it is good to use no more than
five to seven options at once. The correct grouping of the options helps the perceiving,
therefore it would be useful to divide eight options into two clearly distinct groups of
four.
Support laziness and learning
When designing an application, situations evolve many times when making one action
easy complicates the use of others. In this case, the best solution is to support the most
common mode of operation. The simplest actions need to be easy to use even if the
more difficult ones would then require learning and searching.
For example, with mobile phones, the most important functions are calling, answering
and speaking which are all easy to do with fairly few actions. When sending text mes-
sages and browsing the phonebook, on the other hand, the user might have to use the
menus. Furthermore, changing the settings of the phone requires even more familiariza-
tion.
The facilitation of the most commonly used actions is called supporting laziness.
Figure 9. Advanced features of Program Guide can be found
through the color button menus. In the picture, the old version of the
Program Guide which is no longer used.
The Finnish national Program Guide assumes that the viewer will primarily browse the
program information by channels. This is a common habit when reading program in-
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formation in a newspaper. The primary mode of action is in the viewer’s use as soon as
the Program Guide starts.
Another possibility is to browse the information by program genre. However, this is a
more advanced function and requires the use of a color button menu.
Give immediate feedback
Television has always responded immediately when it has been commanded with the
remote control, and this should not change for the worse. The viewer needs to receive
clear feedback immediately after each pressing of a remote control button. If no feed-
back appears, most viewers assume that the command has not succeeded and will press
the button again.
The actions that react to the pressing of a certain button should also not take very long.
Simple actions, such as changing the channel, should be done within half a second of
the viewer’s request. The more complex ones, such as search actions, should be deliv-
ered within two seconds. If the execution of an action requires time, the viewer should
definitely be informed, preferably in advance. It is also polite to offer the viewer the
possibility to cancel the action chosen.
An example of fast feedback can be found on several televisions on analog teletext.
Teletext immediately responds to each pressing of a number button by showing the cor-
responding number on the screen. When an action is being performed, the system tells
this to the viewer – expressing even where the search is going in the object carousel.
From this, the viewer can deduce the remaining time for the search to be concluded.
This type of loading animation buys surprisingly much time with an impatient viewer.
Decide the roles for the remote control buttons
Generally speaking, arrow buttons are used in digital TV user interfaces for stepping on
a menu to the correct menu item, and that choice is activated with the OK button. Color
buttons, which can be used for shortcuts, and number buttons from zero to nine are also
in use.
In Finland, the behavior of the color buttons is guided by loose recommendations de-
fined by Superteletext and the Program Guide according to which the red button should
show the content or the main page of an application and the blue button should show the
settings of the application or the receiver (e.g. language selection) and the instructions.
Figure 10. An example of the color button menu in Superteletext.
The main Finnish channels have adopted a practice according to which Superteletext is
always started with the TXT button, the Program Guide with the yellow color button
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and the service menu with the blue color button. The red color button is reserved for
starting an application attached to a program.
The BACK button found on some remote controls is meant for reversing the choice
made with the OK button, for returning to the previous menu level or for exiting a
menu.
Naturally, it is possible to use the buttons a little differently from the basic model. For
example, in the Finnish Program Guide, the viewer moves from the program listing to
the program description by pressing an arrow button, although this action might also be
considered a choice which should be activated by pressing the OK button. However, in
the Program Guide, the OK button is reserved for selecting the program or channel;
with its help, the viewer can watch the program selected or (in a later version) set re-
minder and save actions connected to the program. The arrow buttons are also used a
little more complexly in Superteletext.
The functions of the buttons should also be taken into consideration when designing in-
teractivity. For example, it is possible to calculate how a certain task can be carried out
with the smallest possible number of pressings. Of course, the mere number of pressings
does not function as an indicator of the efficiency of an application; pressing the same
button twice is faster than pressing two separate buttons. It is also worth noticing that
the most frequently used buttons are found most easily on the remote control.
Support different possibilities in text input
Many application types, such as communication applications, may require text input. A
wireless keyboard may come with some digital TV receivers with which it is easy and
fast to input text, but not all devices have a direct possibility for text input.
There are also alternative ways to input text. The number buttons on the remote control
can be used for character input in the same way as with mobile phones. In that case, it is
good to stick with the character arrangement familiar from telephones because it is not
likely that people want to learn a new mode of operation even if it would be more effi-
cient in connection with some applications.
Text can also be input with a virtual keyboard. The virtual keyboard is shown on the
television screen, and the characters are chosen with a cursor which can be moved with
the arrow buttons and the OK button.
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Figure 11. The virtual keyboard of Superteletext.
An alternative text input method that replaces the keyboard has to be built in an applica-
tion that requires text input. Nevertheless, the application also needs to support the nor-
mal keyboard in case the viewer has one in use.
Be consistent
When the basic lines have been chosen for the navigation and the use of keyboard in the
application, they should be followed in every situation. It is difficult for the viewer to
orientate to a new mode of operation on every view. The usage should also be based on
routine and experience, and the application should not require the viewer to learn ac-
tions separately on each view.
Especially in applications aimed at a wide user group, it would also be good to follow
the operating principles of Program Guide and Superteletext because the viewers use at
least these applications, and their conceptual models and customs are formed based on
them.
Similar to the use logic, the appearance of an application should also be uniform. The
viewer feels safe with a uniform and harmonious application, but if even only one view
greatly differs from other appearance of the application, a sense of being lost immedi-
ately enters the viewer’s mind. The same uniformity of appearance should also be abso-
lutely followed in applications that are connected to a certain television program. The
application has to be uniform with the general appearance of the program.
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3.6 Instructions
The primary goal when designing an application is, of course, that the viewer would
never need separate instructions. The use should be natural and intuitive. Nevertheless,
some instructions are always needed at some point.
There are different uses for guidance. The viewer may choose to read the instructions in
order to familiarize themselves with the application and its potential. They may also
want to check in the instructions whether they have found all the possibilities the appli-
cation has to offer and whether they are using them in the optimal way. On the other
hand, perhaps the viewer only uses the instructions when they are going through all the
functions found in the application.
One use, however, is the most commonly used and the most important one. When
viewer gets lost, do not find the function they are looking for or cannot execute that
function, they will resort to instructions – sooner or later. By the time this occurs, the
viewer has usually already tried to find or execute the function several times and, in
most cases, has been irritated or frustrated when the application has not functioned ex-
pectedly. For this reason, the instructions need to be considerate in a certain manner.
However, too many words in an instruction are also not recommended; the users should
be told exactly how the function is executed.
Format the instructions according to the viewer’s need
The better the instructions can take the user’s real need into consideration, the more use-
ful they are. Every view should, in principle, have its own instruction that would tell the
viewer what is possible on that particular view and how the function is carried out.
However, making this type of instructions can be very difficult. “Intelligent” instruc-
tions, which follow the user’s actions and change their contents accordingly, are not
usually good, because it is very difficult to predict a viewer’s wishes and needs.
A natural manner of offering an instruction is to keep the available options visible all
the time on the user interface and additionally tell about the nature of the functions in a
separate instruction manual.
In a separate instruction manual, it is useful to focus attention on the order in which the
instructions are presented. A manual written from the designer’s point of view often
tells what happens from which button. However, this is seldom the information that the
viewer is interested in. Therefore, the viewer should have an instruction which are based
on the functions or the tasks. “To the beginning: red color button” is better than “Red
color button: to the beginning.” It is also wise to use people not familiar with digital
television to make sure that the expressions are truly understood correctly
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Figure 12. The user interface of the Philips MHP television proto-
type gives a separate instruction at the bottom of the view.
3.7 Usability Testing
Usability testing is often considered vague, expensive and even useless as part of appli-
cation development. However, of all the different methods of usability testing, there is
certainly one that is suitable for all situations, schedules and budgets. In addition, us-
ability testing is practically the only way possible to find out the reaction of the future
users towards the application before the launch. Usability testing carries even more im-
portance in the applications created for interactive television – there are no standard de-
sign conventions formed yet. Therefore, the users do not yet have any idea of the use
methods of the applications, and the designers of the applications do not yet know
which use methods will become most popular.
It has to be noted, however, that no application can be perfectly usable because the users
experience the features of a user interface individually – one user interface cannot pos-
sibly suit everyone.
Define the goals and the indicators
The first useful task to do before beginning usability testing is to define the goals of the
testing. General ease of use is not necessarily always the best goal possible, but the goal
can also be making sure of the usability of some critical parts, such as learning or effi-
ciency.
The goals of usability testing can usually be set according to general design goals and
the target group. For example, in the basic services aimed at all viewers, it is important
that the application is easy to learn to use, whereas this is not equally important with
games that are aimed at youngsters. Alongside testing, it is possible to survey the opin-
ions of the users about the idea, interestingness and features desired of the service.
There have to be indicators for achieving the goals as well: for instance, the time used
for executing a certain task, the number of steps required or the number of mistakes the
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user makes. One important indicator is also the subjective satisfaction of the user.
Sometimes an inefficient user interface is pleasurable.
Points can be given to the results, or the percentages of different results can be used in
interpretation: “30 % of the users considered the user interface easy to use,” “The users
used approximately 5 to 7 pressings of the remote control buttons to execute the task.”
Choose the correct method
Some of the most common methods used in usability evaluation are introduced in the
following section. It is intended that such methods are introduced which are useful at
different stages of application development and suitable for different working habits.
The simplest and easiest methods are described first, the more extensive methods re-
quiring more resources last. Expert help in usability testing is provided by companies
specialized in the field, by Technical Research Centre of Finland (VTT) and by several
universities and colleges.
Usability evaluation should not be merely restricted to the testing of a ready-made ap-
plication – the intention is not to document the flaws of the user interface but to produce
an application suitable for its purpose and user group. At its best, usability testing is a
continuous process in which usability evaluation has been taken as part of the project
starting from the brainstorming and the prototype stage.
Heuristic evaluation means the going through of the functions of an application con-
ducted by an expert. A usability checklist is used as help. Probably the best-known one
is the checklist of heuristic evaluation designed by Molich and Nielsen. However, this
list is not applicable to the evaluation of all interactive television applications as such.
The lists meant for help in heuristic evaluation preferably need to be dealt with as being
approximate – general rules do not necessarily apply for every situation.
Nielsen’s list:
Simple and natural dialog.
Speak the user’s language.
Minimize the user’s memory load.
Be consistent.
Provide feedback.
Provide clearly marked exits.
Provide shortcuts.
Provide good error messages.
Error prevention.
Help and documentation.
Co-operative evaluation and pluralistic walkthrough are suitable to be used as a help
as early as in the design stage; the object of evaluation may just as well be a prototype
as a finished application. In co-operative evaluation both a usability expert and a test
user are present and in pluralistic walkthrough there are also people who have partici-
pated in the designing of the application.
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User testing is best suited for testing a nearly completed application or a functional pro-
totype. User testing is probably the most traditional and most widely used method of
usability evaluation with which it is possible to receive extremely accurate information
of the problem parts of an application and to make sure that the decisions made are the
right ones. In user testing, the application is used in a controlled environment and the
test situation is recorded for later analysis. The test user may have a series of predefined
tasks to perform, or the testing can be based on free form use of the application.
It is essential for the success of the testing that the right type of people are selected for
the task. The test users should correspond to the desired target group as well as possible
with regard to their age, interests and technical readiness.
The amount of orientation and information given to the user in advance should be de-
cided according to the test type and the goals of the test. If the test is only meant for ex-
amining the tasks relevant at the starting of the service, orientation only damages the
results. In long-term use, on the other hand, the viewers learn a lot about the logic and
the basic features of the application which should be explained to the test user when
testing more advanced features.
Three to five users is a good number to have for one test; with the help of five users,
85 % of the problems in an application are found. As many as 15 users are needed for a
100 % result. If the budget and schedule make it possible, it is useful to repeat the tests
after the first improvements and check the changes that were made.
Contextual inquiry means following and interviewing the users in an authentic operat-
ing environment and use situation. The inquiry can be used at the beginning of the de-
sign process to obtain information about the users’ needs or at the end stage of the pro-
duction to ensure the level of usability.
Customer feedback received after the market launch of an application is also an impor-
tant form of usability evaluation because users usually give their feedback based on the
user interface of the application. However, it is wise to verify the results of free form
feedback with some test methods because feedback does not always offer specific in-
formation about the reasons for usability problems.
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4 Properties of the MHP
This section deals with the features of version 1.0.2 of the MHP specification which is
the first version in use. The next version, version 1.0.3, will not have any new features,
but it will correct some of the shortcomings of the specification and define the testing of
different features in order to make all MHP devices function similarly.
The MHP specification can be downloaded at the ETSI website: http://www.etsi.org/.
The downloading requires registering but is free of charge.
4.1 The MHP Application
An MHP application is composed of program files in Java language and the data files
used by the application. The application is transmitted along with the TV signal, and an
MHP device downloads and executes it.
4.2 The Life Span of an Application
An MHP application can either start automatically or at the user’s request. While active,
it can draw graphics on the screen and interact with the viewer. The application can also
be set to a paused state in which case it will remain active in the background. When in
that state, the application can be set active fast.
The life span of an application most often ends when the channel is changed. It is also
possible to signal the same application on several channels so that the application re-
mains running after the channel change. After the application is terminated, the only
information that remains in the memory on the receiver is the data that the application
possibly wrote in persistent storage. Applications themselves cannot be saved in persis-
tent storage until the next generation receivers which comply with version 1.1 of the
MHP specification.
Some MHP receivers offer the viewer a separate menu which can be used to control the
applications. The viewer can see the state the applications are in and start, hide (set to
the paused state) and terminate them.
Release resources in the paused state
An MHP receiver can set an application to a paused state when it wants to show its own
screen graphics. In the paused state the application should release as much of its re-
sources as possible. The most important thing is, however, that the application hides it-
self from view.
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Service menus can also use the paused state of applications that can be started. The
most important applications can be kept in the background all the time in which case
they will start and be in the viewer’s use faster.
4.3 File System
A common way of transmitting files in the digital TV environment is an object carousel
in the broadcast stream. The name refers to a carousel-like action; files are sent continu-
ously in the same order from the transmission end. For the receiver this is shown as a
continuously rotating carousel.
The loading time of files in the digital TV environment is not in direct proportion to the
size of an individual file and bandwidth in use. Often much of the waiting time is spent
on the receiver waiting for the right file to appear. Therefore, in addition to the band-
width, the waiting time is affected by the combined file size of the object carousel. For
instance, the rotation time of a 256 kB carousel with the bandwidth of 128 kb/s is about
16 seconds.
A typical MHP application with its contents is dozens of kilobytes. However, the con-
tents of Superteletext services may require several megabytes altogether.
Special settings can be defined in the object carousel: the files needed to start an appli-
cation can be set to be transmitted every two seconds, or a critical file can be set to be
updated immediately, i.e. as the next file being transmitted to the carousel. A file which
is needed less frequently may be transmitted on every other rotation of the carousel.
The object carousel may also contain clues as to how the receiver should preserve the
files in its cache memory. Unchangeable files can be marked static in which case the
receiver can load them once to its cache, and then they are always quickly available for
the application.
4.4 Return Channel
All MHP devices on the market have some type of return channel. Nowadays it is still
most commonly a regular telephone modem, but Ethernet or cable modem devices are
expected to increasingly enter the market.
As far as the MHP is concerned, any device offering an internet connection can have the
return channel. The pleasantness of use and the price of the connection naturally vary.
Using a secure connection is also possible. The support of the MHP for secured return
channels requires a TLS (Transport Layer Security) server to be used as the server. TSL
differs from the commonly used SSL specification with regard to some parts.
The return channel does not always need to be in the application’s use. The application
can also tell the viewer to send an SMS or to call to a certain phone number. These
types of return channel solutions make it easy to bill from the services. For example, the
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application may allow access to a certain section only if the viewer inputs the right type
of activation code which they have received as a reply to a chargeable SMS.
Figure 13. The Sooda portal retrieves its dynamic content updated
in real time through the return channel.
4.5 Persistent Storage
MHP applications can write some important information in the persistent storage of the
receiver. The application can, for example, save the user information asked from the
user to avoid having to ask that every time the same person uses the application. The
following times it is enough to merely input the PIN code.
There may not be very much space in the persistent storage of the devices, and all the
space is used by all applications. However, if needed, the information written by the ap-
plications can of course be protected from other applications.
4.6 Support for Smart Cards
The current MHP receivers support only Conditional Access (CA) cards. The CA cards
can be used for offering chargeable services.
In the future, OCF-API (Open Card Framework Application Programming Interface,
http://www.opencard.org/) will also become more popular. With its help, smart cards
can be used even wider. For instance, a debit card with a chip can be used for paying or
an electronic ID card for user recognition and electronic signature.
25
4.7 Drawing Layers
There are three different drawing layers on MHP devices. A full sized, full colored I-
Frame picture or a background color can be set on the background layer. Either a full
size or scaled video image can be on the video layer on top of that. The graphics layer is
topmost, and all other graphics drawn by the application are placed there.
Figure 14. MHP graphics are composed of a combination of three
different layers.
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4.8 Resolution
The picture area of all the drawing layers is 720x576 pixels. The picture area is, never-
theless, stretched horizontally according to the aspect ratio chosen, and the pixels do not
remain square-shaped. In the traditional 4:3 aspect ratio, the aspect ratio of the pixels is
16:15, in the aspect ratio 16:9 it is 64:45.
Figure 15. Changes in the aspect ratio affect the graphics of the
screen. Graphics created with the 14:9 aspect ratio are shown too
narrow with the 4:3 aspect ratio, with 16:9 widescreen, on the other
hand, they are stretched horizontally.
A full screen image which is supposed to be shown in the right aspect ratio in wide-
screen should, therefore, be created in size 1024x576 pixels and shrunk at the end to a
720-pixel-wide image. An image meant for the 4:3 aspect ratio is, on the other hand,
created 768 pixels wide. An image that is supposed to be viewed tolerably with both
aspect ratios should be created with the 14:9 aspect ratio and 896 pixels wide. In this
case the image is shown a bit narrow when watching with the 4:3 aspect ratio and a bit
stretched horizontally with the 16:9 aspect ratio.
Avoid thin lines
Television alternately draws even and uneven horizontal lines of the image on the
screen. Owing to this, thin lines often flicker noticeably irritating the eye. Horizontal
lines should, therefore, be at least two pixels thick.
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4.9 Colors
MHP devices have, in principle, a 24-bit full color space with translucency. However,
the color space is often more limited on the graphics layer in real life. Receivers show
the colors in images and graphics as well as possible with fewer colors.
A so-called web-safe palette has been designed for the web environment. All web
browsers support the colors of this palette. The standard colors common for all receivers
have also been specified in the MHP specification.
Figure 16. The palette containing all the colors shown on all MHP
receivers includes 138 colors and 48 translucent colors derived from
those.
There are also restrictions on translucency. In principle, the whole alpha channel is in
use, but the only implementation absolutely required is a 30-% translucency. The re-
ceivers may support more values and always round the translucency to an appropriate
supported value. The implementation of translucency between the elements on the
drawing layer is very slow on many receivers. The translucency for the video layer
functions better instead.
Avoid bright colors
Due to the technology used on television screens, bright colors, especially bright red,
have the tendency to bleed on the screen, and thus full color values should be avoided.
A little less bright, desaturated hues are often also easier to adjust to each other.
With regard to readability, the best colors for text are the shades of white and yellow.
Dark blue or black are good for the background.
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Figure 17. Bright colors bleed on the TV screen.
Use brightness contrast
On the TV screen, brightness contrast stands out better than hue contrast. For instance,
light green text on a dark green background stands out better than dark red text on a
dark green background.
Especially with regard to readability, light-colored text on a dark background is better
than dark text on a light background.
4.10 Vector Graphics
The MHP specification offers the graphics primitives of version 1.1.8 of the Java lan-
guage for drawing vector graphics. Hence, an application can draw on the screen, for
example, lines and rectangles, text and images. However, these graphics have not been
antialized in any way, i.e. curved lines pixelate and seem serrated.
4.11 Pictures
The PNG and JPEG formats are used with certain limitations. In practice, it is always
good to choose the PNG format for pictures which need transparency or translucency.
Pictures should be optimized for the MHP palette. The method used by several receivers
which round the color values to the nearest supported color results in poorer results than
dithering.
29
Figure 18. The picture quality suffers from the limited number of
colors on the graphics layer. The result can be enhanced by convert-
ing the pictures congruous with the MHP palette by oneself. On the
left in the image there is the original picture, in the middle the same
picture converted to the MHP palette without dithering and on the
right the picture converted to the MHP palette with 75 % dithering.
Optimize the file size of the pictures
File size should be taken into consideration with bitmap images. It is often possible to
compress a picture file even to a fraction of the original size without a notable change
on the television screen. However, the optimizing should be done by specifically using a
television; a computer monitor shows pictures differently.
MPEG-2 I-Frame, a still image in accordance with the MPEG2 video format, can be
placed on the background layer. This picture is always shown behind the possible video
picture and graphics. Because the video processor of the device is used for drawing on
the background layer, the image shown on the background layer is always in full color.
4.12 Animation
There is no real support for animation on MHP devices. An application can draw graph-
ics similarly to regular graphic drawing but the somewhat low capacity of the devices
has to be taken into account. It is also possible to use HAVi user interface components
to build a very basic animation.
The MHP also supports the feeding of MPEG-2 P-Frame images to the video decoder,
which enables slow animation (two pictures per second at the most) from video.
4.13 User Interface Components
The Java version of the MHP specification does not include the JFC and Swing classes
which are commonly used in Java applications. Instead, HAVi L2 UI (Home Audio
Video Interoperability, Level 2, User Interface, http://www.havi.org/) user interface
30
component library which is somewhat similar to those classes has been added in the
specification. It includes ready-made user interface elements adapted to the TV envi-
ronment, e.g. text areas, buttons and menus. The HAVi specification has been modified
on some parts and adapted to the MHP specification.
Creating an application may be easier using existing user interface components. How-
ever, HAVi components generally use more memory and require more capacity of the
receiver. An application using HAVi components typically functions slower than an ap-
plication the user interface components of which have been implemented using the Java
language.
Figure 19. The layout of the HAVi components is different with
different receivers.
4.14 Fonts
Digital TV receivers have one built-in font, Tiresias. According to the MHP specifica-
tion, all receivers have to support at least the PLAIN type and sizes 24, 26, 31 and 36
points of Tiresias. In reality, there are more sizes on each receiver, but the sizes that are
specified always have good quality. Other sizes may be of worse quality. Some receiv-
ers support antializing and kerning. The latter influences the space that text requires,
which is why text may be positioned differently with different receivers.
In addition to a built-in font, there are font files which are transmitted with the applica-
tion and which can also be used. The file format of these files is PFR (Portable Font Re-
source, http://www.truedoc.com/). Bitstream (http://www.bitstream.com/) offers a tool
for converting TrueType and PostScript fonts into the PFR format.
When using downloadable PFR font files, it is good to pay attention to the file size. Few
applications need all characters specified for a font. The largest font files, containing all
Unicode characters, may be several megabytes in size whereas it is possible to reduce
the size of a font file to a few kilobytes by excluding characters.
Changes in aspect ratio also affect the drawing of the characters. The characters are
drawn by default according to the 14:9 aspect ratio (pixel resolution 896x576, pixel as-
pect ratio 56:45) in which case they are drawn a little too thin with the 4:3 aspect ratio
and horizontally a little spread with the 16:9 aspect ratio.
31
The MHP specification offers the possibility to adjust the aspect ratio according to
which the characters are drawn but that interface had not been implemented on any re-
ceiver on the market when this guide was being written.
Use sans-serif fonts
A sans-serif font drawn with an equal stroke thickness is the clearest font type on the
TV screen. Serifs and hairlines suffer from a low resolution and changes in aspect ratio,
making the characters illegible.
Figure 20. Sans-serif Tiresias drawn with a stroke of equal thick-
ness suffers from changes in the aspect ratio and low resolution less
than the serifed Garamond using a thin stroke.
More information on the readability of text in the TV environment can be found in
Jarkko Haataja’s Master’s thesis:
http://www.media.hut.fi/GTTS/Suomi/dt&raportit/DI_J_Haataja.pdf.
32
Licensing Tiresias
Many content producers need the Tiresias font in the PC environment
to be able to preview content looking as they should. The font is li-
censed by Bitstream under the name Tiresias Screenfont.
Contact information:
Bitstream Inc.
Sales Dept.
245 First Street
17th Floor
Cambridge, Massachusetts 02142, U.S.A.
E-mail: sales@bitstream.com
Web: http://www.bitstream.com/
4.15 Sounds
Applications may play sound from files. The format for sound files is MP2 (MPEG 2
Audio Layer 2 compression).
Depending on the receiver, the TV sound audible in the background may be audible to-
gether with sound played by the application or stop while sound is played. An applica-
tion cannot adjust the volume of sound attached to the TV broadcast but it can mute it
when needed.
Let the sound of the TV program be audible in the background
It is usually good to let the sound of the television broadcast be audible in the back-
ground of an application. This way the viewer knows what is happening in the back-
ground, and they can leave the application when they hear that the TV program they
have been waiting for begins.
Pay attention to the size of the sound files
Sound files are usually big in size, and thus they slow application downloading from the
carousel and take up more memory from the receiver.
4.16 Video
One of the most important elements of a digital TV application is naturally the TV
broadcast itself. The TV picture can be used as part of the application graphics either in
full size or scaled to a smaller size. The MHP specification requires that the devices
support the scaling of the TV picture to at least one fourth of the original size, but all
33
devices on the market change the size of the TV picture almost without restrictions.
Therefore, a smaller picture size can be used at the moment at least. A scaled picture
can be placed at any point on the screen.
Use TV picture with consideration
When used as a graphic element, a television picture should be used with consideration.
Even though it is good to let the viewer know what is happening in a TV program, the
sound of the program is often enough for this purpose. A moving picture draws the at-
tention of the eye towards itself and disturbs the reading and the perceiving of the appli-
cation.
Hence, the TV picture should mainly be used in applications connected to the TV pro-
gram and in which the TV program is meant to get attention. The TV picture is also of-
ten used on the main page of an application in order not to make the shift from a TV
program to an application covering the entire screen too sudden with regard to the use
experience.
Figure 21. The Eduskuntafakta (Parliament fact) application on
YLE24 shows the TV picture as part of the user interface. This way it
can be used for browsing information about the way the Parliament
operates while watching a talk show for example.
34
4.17 Remote control
The DVB-MHP standard specifies the minimum requirements for the remote controls of
digital television devices. A remote control should have at least the following buttons:
• arrow buttons up, down, left and right
• OK
• TXT
• number buttons 0-9
• Color buttons in the following order: red, green, yellow, blue
The OK and TXT buttons can be described in another way on the remote control, such
as with a symbol.
There may also be other buttons in the applications’ use, such as the BACK button, but
the application user interface should not require that these buttons be used. Instead,
there may be functions in an application the use of which is easier with the extra but-
tons.
Figure 22. Different remote controls of MHP devices.
There may be a wireless keyboard in use for text input. There have been different key-
boards and keyboards embedded in the remote control in prototypes of different device
manufacturers, but no keyboard was available for any receiver on the market even as an
accessory when this guide was being written (spring 2004).
35
Visualize the color buttons as a group
When color buttons are used in an application, it is important that all the color buttons
are always shown as a group and in the same order. The color buttons should be on the
remote control in the order of red, green, yellow, blue.
Figure 23. In an application, the color buttons should be visual-
ized as a group, similarly to the remote control.
If only a red ellipse and text connected to it is shown on the screen with an application,
that the red ellipse is only a spot for many viewers. Without anything to compare it to,
the viewer does not know whether they should pay attention to the shape or color of the
spot. When all colors are visualized as a group, they are more easily connected in the
viewer’s mind to the corresponding button group on the remote control.
Another reason for always presenting all the color buttons in the same order is color
blindness. It is difficult to choose between red and green if both colors look the same.
The colors are always difficult to distinguish on a black-and-white screen although not
many black-and-white TV sets will have the privilege of being connected to a digital
set-top box.
4.18 Data Security and Data Protection
The MHP specification has support for the security model of applications. For example,
applications using the return channel have to be signed electronically in order for the
receiver and the viewer to identify their origin. Otherwise an application which has been
connected to the program stream may at some point, for instance, call to a premium rate
phone number without the user knowing it. An application also has to be signed to be
able to use the persistent storage of the receiver or to change the channel. Detailed per-
missions are specified for signed applications for executing certain actions.
When this guide was being written (spring 2004), the security model had not been im-
plemented in full. The DVB organization is in the process of organizing co-operation
between the providers of authentication services to implement the whole certificate
chain. At the moment, the weaknesses of the chain are avoided with different methods
on different receivers.
36
5 Superteletext
Superteletext replaces the old analog teletext in the digital era. Compared to its prede-
cessor, it has plenty of new features, such as more impressive graphics, links familiar
from the web environment and the possibility to more extensive and targeted content
through the return channel.
Superteletext is a content-based service platform in the digital television environment. It
is significantly easier for content producers to provide services through Superteletext
than to implement their own MHP application.
The Superteletext browser itself is like a web browser in the internet environment. Its
XHTML-based markup language is very close to the HTML language on web pages.
Superteletext offers a ready-made user interface with which is it possible to show and
use services. When implementing Superteletext services, one only has to concentrate on
creating content.
Figure 24. The news page of the YLE Superteletext service.
Each channel may have its own Superteletext service but several channels can also use
the same Superteletext content.
Existing web services are also fairly easy to convert into functioning Superteletext ser-
vices. However, this process always requires a little adapting due to the different way of
use and interface of television.
37
Using an existing application can also significantly reduce the need for testing and
maintaining. The application is adapted to function on every MHP device on the Finnish
market, and the maintenance continues with software updates, and content producers do
not have to worry about this.
This section is mostly based on the Superteletext platform used by digital terrestrial op-
erators in Finland. The platform is implemented by Sofia Digital
(http://www.sofiadigital.fi/). Cable television operators will also mostly support Su-
perteletext-type browser solutions. Examples of other browser solutions are ACE by
Ortikon (http://www.ortikon.com/) and Pontegra by German Nionex
(http://www.nionex.com/). More detailed content production manuals for all the appli-
cations are available, and these manuals provide information about all the features of
the applications and of their use.
Figure 25. The course information of Helsinki University of Tech-
nology developed in the Motive project is built on the Ortikon Interac-
tive DVB-HTML browser.
5.1 Superteletext Features
Markup language
The markup language of Superteletext is based on the DVB-HTML specification of ver-
sion 1.1 of the MHP specification. However, only a small proportion of the features of
the DVB-HTML specification is in use. Content description is based on the XHTML
language, and the layout is defined with the CSS2 language.
38
Page layout is freely definable. Elements for text, images, television picture and links
are available. Some features of the appearance of the elements that can be defined are,
among other things, color, background and the color and thickness of the borders.
One special feature of Superteletext used by terrestrial operators is its support for full
color pictures. Hence, it is possible to place one or more pictures in the background in
the page content in addition to the I-Frame, and these pictures are shown in full color
regardless of the smaller color space on the receiver’s graphics layer. A separate tool is
needed to produce these pictures.
Browsing
The viewer can move between the pages in many different ways. The arrow buttons to
left and right are used for moving between the sub-pages to the beginning and the end.
When navigating from the first sub-page to the left, the viewer moves to the beginning
of the previous page, and correspondingly, from the last sub-page to the right, the
viewer moves to the beginning of the following page.
The Superteletext browser automatically divides the content of a page into sub-pages if
the content does not fit on one page. The browser shows the number of sub-pages and
the number of the current sub-page on the status bar.
It is possible to separately specify the previous and following page for each page. These
pages can also be given names which the browser will show on the status bar.
Figure 26. The arrow buttons left and right on the remote control
can be used for browsing between Superteletext pages. The arrow but-
tons up and down are used for traversing links.
39
No previous or following page is necessarily specified for pages. The viewer has to use
links or color buttons to move forward from this type of page.
Figure 27. Navigation can also be implemented entirely with links
in which case all arrow buttons are used to move the cursor.
Links
It is also possible to use links to navigate between the pages. The arrow buttons up and
down are used for traversing between the links, and a link is activated with the OK but-
ton.
Any element on a page can be a link. A link can refer to another Superteletext page or to
a separate application that will be started when the link is activated.
Number buttons
The three-number page codes familiar from analog teletext are also in use. The number
space available for one Superteletext service is from 000 to 999. However, not all pages
need to have their own page number.
The viewer moves to the page with a number code by entering the code of the page with
the number buttons.
The Superteletext browser itself does not show the number code specified for a page,
this has to be defined as part of the content of a page if it should appear on the page.
40
Color button menus
Color button menus are also in the viewer’s use. The red menu, Content, is defined ac-
cording to the service to include the main pages of the most important sections. The
content of the green and yellow menu can be defined according to the page. On the blue
Options menu there can generally be found instructions for the browser, the language
selection of the user interface (Finnish and Swedish in Finland) and the possibility to
increase the font size. The content of the menu opened by the blue color button is also
defined according to the service.
The green and yellow color buttons can also be used as shortcuts. In case only one menu
item is specified as the content in the color button menu, the color button in question
will function as a shortcut. In this case, the viewer will be directed straight to the page
specified and no menu will be opened.
Return channel
It is also possible to refer from Superteletext content to content on an internet server.
This type of content is retrieved through the return channel. It is also possible to refer
from the return channel content to files transmitted along with the TV broadcast.
Markup language also supports the commonest form elements with which it is easy to
communicate with regular web servers and to use already implemented web services.
5.2 Content Production Process
Define the size of the content
When the project for creating Superteletext content begins, the first task should be to
take a look at the communication needs and at the content which should be transferred
to television. There may already be existing content as the base, for instance an existing
web site. The amount and nature of content greatly defines the structure and use logic of
the site.
The Superteletext system does not itself really define any conditions for the content.
The information on a page may form a news site, a chat room, a product demonstration
or a trade place. Instead, it is the environment that sets conditions; the data transfer ca-
pacity is limited, and not all viewers have the possibility to use the return channel of
their MHP receiver.
On the Internet it is possible to provide any type of content. It is cost-effective to offer
content even for marginal groups of only a few people and, on the other hand, linking
makes it possible to present extensive topic entities and to have very detailed informa-
tion. In the television environment on the other hand the capacity is limited, and that is
why the content is more often of interest to a wide audience.
41
More personified content can be offered through the return channel. However, one has
to note that this content cannot be used by all digital TV viewers. The return channel
has not been connected on all receivers.
Think through the need for updating
The implementation of a page is greatly affected by whether it is a matter of static con-
tent which can be created once, or a dynamic, constantly changing site which does not
need to be updated frequently.
If a site is created to be a complete and fixed entity from the beginning, a specific, logi-
cal structure can be built between the pages. The size and structure of an entity and, for
instance, the headings of the next and previous page can be expressed to the viewer on
the pages. The appearance of the pages can also be improved to be optimal unlike with
the automatic creation of the pages.
Build a path for browsable content
Pages which the viewer is supposed to read in a certain order or to browse without a
specific need for information are good for a linear structure. The structure may be linear
in a product demonstration site where the viewer moves from a general description to a
more detailed description of the product features, technical features and finally to price
information. Another example could be a news site where domestic news forms a cer-
tain entity.
Figure 28. Browsing contents is easy when the pages are linked
directly to one another.
The pages on a product demonstration site are arranged in an order in which the pre-
senter wishes to tell about the product. Generally, the linear navigation method should
be supported. The pages should be linked to each other with “previous” and “next” links
which can also be labeled. This way the users know that on the Features page a pressing
to the left takes them back to the general descriptions whereas a pressing to the right
takes them to the technical description of the product.
42
With links to the previous and next page, the most common use method, reading from
start to finish, is supported. In addition, it is good to offer information on the scope of
the site and the content it has to the viewer as early as on the first page, that is, to tell
about all the pages included in the site. Because no remembering should be required of
the viewer, it would be useful to show this information on every page. All pages could
be collected to a link list from which the viewer can easily access different pages. How-
ever, if this takes too much space on the page or makes the content too confusing, color
buttons can also be used as links, as shortcuts or menus.
With sites using a linear navigation, it is important that the linearity remains logical and
uninterrupted all the time. Even though it is possible to define the links for the next and
previous pages to point at any page at all, the user only expects a certain navigation path
which advances from left to right. The link pointing back should, therefore, always take
the users back to the page from which they came to the current page.
Make the search faster with a hierarchy
If the content that a Superteletext site offers is extensive and only a limited part of the
pages are interesting to individual viewers, it is useful to arrange the pages according to
a tree-like hierarchy. From different types of news, the domestic and world news should
be in their respective sections similarly business and sports.
Even more clearly treelike structures appear in the possible contents. For example, the
classified advertisements might be divided into several categories for the viewer. On the
buying and selling sites, the items are divided into several categories and subcategories.
If a viewer wished to buy a new car, he or she would probably not want to go through
all the advertisements found on the site. This is why it is good to separately classify the
material to advertisements dealing with buying or selling. A category Transportation
could be found in the selling advertisements, and in there a category Vehicles which
would be further classified according to the make and possibly even model. On a site
classified this way, the viewer would find the first interesting advertisement after six
pages instead of after having to go through possibly two hundred other advertisements.
It would be useful to further continue the classification of the above example into
smaller categories. The makes of the cars could be classified into an alphabetical list
according to the first letter, in which case getting to “Volvo” would be faster. In any
case, the division into categories as small as possible is the best choice – there should be
no more than seven choices on a page. This is due to the way people perceive things and
to the requirement of the efficiency of the navigation as well: the user is faster directed
to the eighth option with one pressing to the right and after that with one pressing down
instead of eight pressings altogether.
On those Superteletext sites which support the treelike structure, it is also important to
offer a return route to an upper level of the hierarchy. This can be done with color but-
tons, for instance, either with a shortcut to an upper level or with a menu that lists all the
levels.
43
Figure 29. Getting to the contents of certain topic area is easy
with a menu.
Combine navigation methods carefully
The most flexible mode of operation is reached by combining the linear and tree-like
navigation methods. If there are several categories on one level in the tree hierarchy, the
categories can be divided into several consecutive pages, for example, six options on
each. This way the viewer easily finds the right category by browsing the pages.
However, when combining navigation methods, special attention has to be focused on
preserving the user interface as natural and uniform. Changing the navigation method
requires adjusting and adapting from the user.
If the page number of a certain page is to be emphasized, the page number should be an
essential part of the content of the page. Additionally, the page number can be repeated
on every link and color menu item in order for it to better stay in mind.
List the links one below the other
It has to be noted that the mode of operation of the digital teletext browser differs from
the use of a web browser. No freely movable mouse is in use, but the arrow buttons up
44
and down are used for moving between the links. This is why there should not be too
many links on a page.
Because of the way they are used, links should be placed on the page one below the
other. It is easier and more consistent to move between links on a separate list than be-
tween links that are placed in the text.
Separate the content and layout
Nowadays almost all news content is stored in and published from databases. Ready-
made page templates define the structure and layout of the pages, and only the text con-
tent and pictures change on the pages.
When creating dynamic content, attention has to be paid to creating style definitions for
them to function with all the content meant for a site. For example, separate page tem-
plates can be created for pages that contain only text and for those with only pictures. It
is simpler if all pictures in the page content are of the same size and fit in the same
place. Naturally, there is a difference in the direction of line – some of the images suit
better on the left side of the page, some of them on the right side.
Even if every page was created separately, it is, nevertheless, useful to separate the con-
tent and the definition of the formatting of its layout. When style definitions are com-
bined in one file, changes in the page layout are easier to make and the total file size of
the site remains small.
5.3 Tools for Content Production
XHTML content used by Superteletext can be produced with any text editor. Most of
the content is still published automatically from databases using ready-made page tem-
plates.
The best tool for creating page templates is the editor designed for Superteletext. It in-
cludes a number of useful tools, such as an image converter for creating full color pic-
tures optimized with regard to the file size and used by Superteletext and also a PC
emulator with which it is possible to preview the contents from everyone’s own work
station. The final testing should, however, be conducted in a more real environment.
The use experience with a real TV and a remote control differs greatly from browsing
with an emulator.
Other HTML and XML content development tools (e.g. Macromedia Dreamweaver,
http://www.macromedia.com/) can also be adjusted to Superteletext production.
45
Figure 30. The Superteletext emulator enables the previewing of
the contents on a computer screen.
Figure 31. The Editor tool meant for creating Superteletext page
templates.
46
6 Application Development
Not all services can be implemented as Superteletext contents. In those cases a separate
MHP application has to be implemented. Making and maintaining it requires more re-
sources but, on the other hand, an independent application also provides more possibili-
ties. It has to be noted that compared to the development of PC applications the devel-
opment of MHP applications is very demanding due to minimal device resources on the
one hand and to the requirements of reliability on the other. The immaturity of the re-
ceiver environment and the early development stage of specifications also bring forth
more challenges especially in the application testing.
An example of a separate MHP application is the service distributed as an enhancement
of the program Idol on MTV3. The service offered extra information about the competi-
tion and the competitors but also the possibility to capture still images from the TV pic-
ture and send them to MMS phones.
Figure 32. The application broadcast with the Idol program on
MTV3 with which it is possible to capture pictures from the TV pro-
gram and send them to MMS phones.
There are tools available for the development of separate applications. For example,
Finnish Cardinal Studio (http://www.cardinal.fi/) offers the possibility to compile appli-
cations with an easy-to-use user interface. Of course, application development tools
have their limitations and all features of the MHP specification can only be used by
programming the application with Java code.
47
Figure 33. NE-Spelet on FST in an independent game application.
Figure 34. Cardinal Studio is an easy-to-use application develop-
ment tool.
The development process can be helped with MHP emulators run in the PC environ-
ment (for example, XletView, http://sourceforge.net/projects/xletview/, and OpenMHP,
http://www.openmhp.org/). With an emulator it is possible to start the development
process but the application itself has to be tested with several real MHP receivers.
48
6.1 Testing
Content that has been developed by the content providers themselves require a lot more
testing than Superteletext content. Different receivers work differently and implement
different features of the MHP specification.
All features of an application have to be tested with all receivers on the market. Testing
also has to be repeated every time there is a software update for any receiver.
Light-weight signaling tools are available for testing. These tools create an object car-
ousel from the application files and attach it to a video file as complete multiplexes.
These tools are sold at least by Finnish Cardinal Systems (http://www.cardinal.fi/) and
Korean Aircode (http://www.aircode.com/) and DTV Interactive
(http://www.dtvinteractive.com/).
Figure 35. With Cardinal Playout, it is possible to create a testing
environment resembling a real broadcast network for the signaling of
the applications.
Devices needed in testing an application can also be rented. At least Digita
(http://www.digita.fi/) offers a complete testing environment as a service.
The MHP Interoperability Workshop meetings which are organized a couple of times a
year in Germany in the IRT (Institut für Rundfunktechnik, http://www.irt.de/) facilities
offer the best possibility to test applications with different signaling devices and receiv-
ers.
49
7 Adapting Finished Services to Digital TV
Many content producers and service providers see digital TV as merely one new distri-
bution channel for existing content and services.
Figure 36. Many content producers see digital TV as merely one
distribution channel among several. The contents of Savon Sanomat
can also be found on the digital TV network of 3KTV.
Web-based services can often be adapted to the Superteletext environment with only a
little effort. The adjustment does not usually work completely automatically, though;
there is such a big difference between the television user interface and a web browser.
The adapting is easiest from services built for mobile devices.
The layout has to be separately created for web pages when they are in the TV envi-
ronment. Use logic often has to be refined as well. However, most of the time it is
enough to once create page templates that define the structure of the service and the
style definitions (style sheets) that define the layout. After this, the content of the pages
can be retrieved from a database and input in ready-made page templates. The content
updating will be completely automatic from there on.
The Superteletext services of YLE, MTV3 and Channel Four Finland all use the same
content which is published on their web pages. The data in the database is merely at-
tached to different page templates according to the publishing medium.
50
Figure 37. The schedule information of Tampereen kaupungin
liikennelaitos is retrieved to a service in test use from the schedule
service on the Internet, and it is signaled along with the application.
Figure 38. Uutisrulla by YLE shows regularly updating news.
51
Figure 39. Converting existing web services into services that can
be used with digital TV browsers is often easy although the user inter-
face usually has to be separately created for the TV environment. The
image shows an email application on the 3KTV network.
In services using the return channel, the amount of content on broadcast network should
be minimized. The pilot version of the Lotto service by Veikkaus uses the Superteletext
page by MTV3 as the starting page and pages loaded via the return channel in the exe-
cution. The downloadable pages are on the same servers as the web pages. The pages
and use logic has been adjusted to the TV environment, and the user interface is being
developed stage by stage gathering use experiences by piloting the service publicly.
The banking service by Osuuspankki is an independent application which can also be
started from a Superteletext page. It, too, uses the bank’s already existing service archi-
tecture.
Existing Java applets can also be adapted as MHP applications. However, this often re-
quires significantly more work.
52
Figure 40. The pilot version of the Lotto service by Veikkaus uses
the return channel features of Superteletext.
Figure 41. A digital banking service of Osuuspankki.
53
8 Distributing a Service
The program license holders and network operators are in the process of preparing sys-
tems with which it is possible to publish and maintain applications and the content of
Superteletext. These systems are different for each party.
The general principle is for the service provider to deliver an application or the contents
to a program license holder or a network operator which then adds the service among
other services. It depends on the nature of the service and especially on its need for up-
dating what type of connection is needed between the service provider and the party re-
sponsible for the signalling.
Once a service has been created, it is enough that it is delivered to the operator with the
appropriate information. The contents of some applications may need frequent updating
in which case the method of updating has to be agreed upon. It is sometimes necessary
to create a separate, automated system which constantly updates the data on broadcast.
Signaling becomes even more complicated if the application is synchronized with the
TV program. Then the synchronization triggers have to be input into the broadcast
automation system, and it needs to be verified that they pass the system, and the possi-
ble delay has to be measured.
Applications may be on broadcast all the time or only at certain times, especially at a
certain time of day or during a certain TV program.
Signaling a service is not enough, though. The service, of course, has to be advertised,
and people have to know it exists. In addition, the service has to be easy to find and
start.
The following introduces some models with the help of which a service can be made
accessible to a big audience. More current information can be found at the ArviD pro-
gram web site (http://www.arvid.tv/).
8.1 Superteletext Contents
As part of the Superteletext service, signaled contents are most easily found on the main
page of a channel or with a link on any other well-known page. Another possibility is to
reserve a page number out of all the numbers in the Superteletext service for the main
page of the service offered. This page number can then be used when advertising the
service.
54
8.2 Service Menus
A service menu is a special MHP application with which other MHP applications are
managed. The service menu shows the viewer a list of applications and services avail-
able, it can also show a small icon on the screen whenever an interactive service has
been attached to a TV program. With the service menu, individual services can be pre-
loaded in which case they start faster when needed.
Figure 42. The YLE service menu is opened with the blue button
and shows a list of all applications that can be started.
Figure 43. The Do icon of MTV3 informs an interactive enhanced-
TV service available and encourages the viewer to press the red but-
ton.
The service menus can be dynamic and automatically list all applications that can be
started, or they can be more specified in which case different applications and services
can be grouped as different entities.
Program Guide can also list MHP applications and services found on the Internet. Al-
though, this feature has not yet been used very widely.
In the cable TV environment, the service menu is offered by the cable operator, and it is
similar on all channels.
55
Figure 44. In a service menu, applications and services can also
be grouped under different themes. The example image is from a pro-
totype of the TTV service menu.
Figure 45. Program Guide shows a list of available MHP ser-
vices.
56
8.3 Own Service Channel
Of course, one possibility is to set up a separate, for instance temporary, channel for a
service or a service group. Such a channel could function as a portal for several services
of the same topic area.
For example, a Tieke publication Julkishallinnon palvelut ja niiden mahdollisuudet
digitaalisessa televisiossa proposes an idea of a joint service portal for service providers
in the public sector.
8.4 Terrestrial Distribution
The content and applications on terrestrial distribution reach a wider audience. To reach
all digital TV viewers, commercial service providers have to, at least for now (spring
2004), agree on transmitting their services on cable distribution separately with the ca-
ble operators.
It is possible to have one’s own service in view either through a program license holder
(YLE channels, MTV3, SubTV and Channel Four Finland) or a network operator
(Digita).
8.5 Cable Distribution
The cable network offers significantly more capacity for services and content than the
terrestrial network. In addition, it is possible to implement local and regional content
more freely on a cable network than on a terrestrial one or in satellite transmission. On a
cable network, the desired services can be transmitted even to only one or two towns if
needed.
The services and applications transmitted on cable networks by cable operators are
mostly in the viewers’ use via a service menu provided by the operator. The service
menu is the same on all channels, and hence all services transmitted on a cable network
can be started on all channels transmitted by the operator.
Transmitting any type of commercial services on a cable network requires a contract
with the cable operator.
57
Sources
Portals and Link Lists
ArviD The web pages of the AdviD program by the Ministry of
Transport and Communications Finland.
http://www.arvid.tv/.
Digitv.fi An extensive, general digital TV site maintained by
Digita.
http://www.digitv.fi/.
Digi-TV sovelluskehittäjän A comprehensive link list of the MHP by Juha Laakso.
linkkilista http://koti.mbnet.fi/digitale/mhp/mhp.html.
Reports and Publications
Digi-TV:n palveluntekijän A Guide for the Digital TV Service Provider. This guide
opas was based on the Digital TV guide by Tekes.
http://www.tekes.fi/julkaisut/Digi_TV_opas.pdf.
Julkishallinnon palvelut Publications of Tieke, Finnish Information Society Devel-
ja niiden mahdollisuudet opment Centre, ISSN 1459-6490. Vol. 12 in the
digitaalisessa televisiossa publications. ISBN 952-9714-31-9. Downloadable at the
Tieke web site, http://www.tieke.fi/.
Kohti digiaikaa Publications of the Ministry of Transport and Communica-
tions Finland 52/2003. Downloadable at the web site of
the ArviD program, http://www.arvid.tv/.
Usability
Digitaalisen television The M. Sc. thesis by Jouni Haataja deals with readability
luettavuus in the digital TV environment.
http://www.media.hut.fi/GTTS/Suomi/dt&raportit/DI_J_H
aataja.pdf.
The Killer App is TV Designing the Digital TV Interface. Information about TV
user interface design.
http://www.ergogero.com/pages/digitaltv.html.
58
WWW-palveluiden Information about usability mostly adapted to the web en-
käytettävyys ja tuotanto vironment.
http://www2.uiah.fi/mediastudio/survey4/.
Organizations and specifications
DGTVI The Italian national digital TV organization.
http://www.dgtvi.net/.
DVB Digital Video Broadcasting organization has created the
DVB standards for digital TV distribution and the MHP
specification.
http://www.dvb.org/.
ETSI A standardizing organization at the web pages of which
the MHP standard can be downloaded (the downloading
requires registering).
http://www.etsi.org/.
F.U.N. Free Universe Network. A digital TV organization of the
German-language market.
http://www.fun-tv.de/.
HAVi A part of the user interface elements of the MHP are based
on the Home Audio Video Interoperability specifications.
http://www.havi.org/.
MHP Multimedia Home Platform.
http://www.mhp.org/.
NorDig A Nordic digital TV organization.
http://www.nordig.org/.
OCF The Open Card Framework interface is part of version 1.1
of the MHP specification. It has already been taken into
use on MHP receivers in Italy.
http://www.opencard.org/.
Truedoc Information about the PFR fonts included in the MHP
specification.
http://www.truedoc.com/.
59
Companies
ADB ADB manufactures MHP receivers and also sells special
versions manufactured for development use in their net
shop.
http://www.adbglobal.com/.
Aircode Aircode offers a light-weight signaling tool for test envi-
ronments.
http://www.aircode.com/.
Bitstream Bitstream licenses the Tiresias font for the PC environ-
ment and offers tools for converting fonts into the PFR
format.
http://www.bitstream.com/.
Cardinal Systems Cardinal Studio by Cardinal Systems is an easy-to-use ap-
plication development tool. With Cardinal Playout it is
possible to build a light-weight digital TV signaling envi-
ronment.
http://www.cardinal.fi/.
Digita The network operator of the Finnish digital terrestrial net-
work.
http://www.digita.fi/.
DTV Interactive DTV Interactive offers a light-weight signaling tool for
test environments.
http://www.dtvinteractive.com/.
Galaxis Galaxis Technologies offers MHP implementation for the
digital TV receiver boards of computers.
http://www.mhp4free.de/,
http://www.galaxis.de/.
IRT A research and development institute of German-language
broadcasting companies where MHP Interoperability
Workshops are organized to enhance the compatibility of
devices and applications.
http://www.irt.de/.
Macromedia Macromedia Dreamweaver is a popular HTML editing
tool which can also be adjusted to DVB-HTML content
production.
http://www.macromedia.com/.
Nionex The MHP browser by German Nionex is called Pontegra.
http://www.nionex.com/.
OpenMHP An MHP emulator for PC use developed in Finland.
http://www.openmhp.org/.
60
Ortikon Interactive Ortikon Interactive offers digital TV services and applica-
tions. Digita uses the browser solution by Ortikon.
http://www.ortikon.com/.
Sofia Digital Sofia Digital offers digital TV services and applications.
Sofia Digital has implemented the Superteletext system.
http://www.sofiadigital.fi/.
XletView With the XletView emulator, MHP applications can be
emulated in the PC environment.
http://sourceforge.net/projects/xletview/.
61
Figures
Figure 1. Illustration, © Sofia Digital. 4
Figure 2. Illustration, © Sofia Digital. 5
Figure 3. Screen capture, © Sofia Digital. 7
Figure 4. Screen capture, © Sofia Digital. 8
Figure 5. Screen capture, © Sofia Digital. 8
Figure 6. Screen capture, © Sofia Digital. 9
Figure 7. Screen capture, © Sofia Digital. 9
Figure 8. Illustration, © Sofia Digital. 11
Figure 9. Screen capture, © Sofia Digital. 15
Figure 10. Screen capture, © Sofia Digital. 16
Figure 11. Screen capture, © Sofia Digital. 18
Figure 12. Photo, © Sofia Digital. 20
Figure 13. Screen capture, © Ortikon Interactive. 25
Figure 14. Illustration, © Sofia Digital. 26
Figure 15. Illustration, © Sofia Digital. 27
Figure 16. Illustration, © Sofia Digital. 28
Figure 17. Photo, © Sofia Digital. 29
Figure 18. Illustration, © Sofia Digital. 30
Figure 19. Screen capture, © Sofia Digital, application © Twonky Vision. 31
Figure 20. Illustration, © Sofia Digital. 32
Figure 21. Screen capture, © Sofia Digital. 34
Figure 22. Photo, © Sofia Digital. 35
Figure 23. Illustration, © Sofia Digital. 36
Figure 24. Screen capture, © Sofia Digital. 37
Figure 25. Screen capture, © Ortikon Interactive. 38
Figure 26. Illustration, © Sofia Digital. 39
Figure 27. Illustration, © Sofia Digital. 40
Figure 28. Illustration, © Sofia Digital. 42
Figure 29. Illustration, © Sofia Digital. 44
Figure 30. Screen capture, © Sofia Digital. 46
62
Figure 31. Screen capture, © Sofia Digital. 46
Figure 32. Screen capture, © MTV3. 47
Figure 33. Screen capture, © Sofia Digital. 48
Figure 34. Screen capture, © Cardinal Systems. 48
Figure 35. Screen capture, © Cardinal Systems. 49
Figure 36. Screen capture, © 3KTV. 50
Figure 37. Screen capture, © Sofia Digital. 51
Figure 38. Screen capture, © Sofia Digital. 51
Figure 39. Screen capture, © 3KTV. 52
Figure 40. Screen capture, © Sofia Digital. 53
Figure 41. Screen capture, © Sofia Digital. 53
Figure 42. Screen capture, © Sofia Digital. 55
Figure 43. Illustration, © MTV3. 55
Figure 44. Screen capture, © Ortikon Interactive. 56
Figure 45. Screen capture, © Sofia Digital. 56
63
Further Information
ArviD-programme WWW-site
http://www.arvid.tv/
Ministry of Transport and Communications Finland WWW-site
www.mintc.fi