IEC PAS 62298:2002

IEC/PAS 62298
Edition 1.0
2002-01
TeleWeb Application Profile 1
Reference Decoder
PUBLICLY AVAILABLE SPECIFICATION
INTERNATIONAL Reference number
ELECTROTECHNICAL
IEC/PAS 62298
COMMISSION
IEC/PAS 62298
Edition 1.0
2002-01
TeleWeb Application Profile 1
Reference Decoder
PUBLICLY AVAILABLE SPECIFICATION
INTERNATIONAL Reference number
ELECTROTECHNICAL
IEC/PAS 62298
COMMISSION
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
TELEWEB APPLICATION PROFILE 1
REFERENCE DECODER
FOREWORD
A PAS is a technical specification not fulfilling the requirements for a standard, but made available to the

public and established in an organization operating under given procedures.

IEC-PAS 62298 was submitted by the EACEM (European Association of Consumer Electronics Manufacturers)
and has been processed by IEC technical committee 100: Audio, video and multimedia systems and
equipment.
The text of this PAS is based on the This PAS was approved for
following document: publication by the P-members of the
committee concerned as indicated in
the following document:
Draft PAS Report on voting
100/407/PAS 100/438/RVD
Following publication of this PAS, the technical committee or subcommittee concerned will investigate
the possibility of transforming the PAS into an International Standard.
An IEC-PAS licence of copyright and assignment of copyright has been signed by the IEC and EACEM
and is recorded at the Central Office.
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising with
the IEC also participate in this preparation. The IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any divergence
between the IEC Standard and the corresponding national or regional standard shall be clearly indicated in the
latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this PAS may be the subject of patent rights.
The IEC shall not be held responsible for identifying any or all such patent rights.
Page i
GENERAL SECRETARIAT
EACEM Technical Report
TR-045-r01
Title:
TeleWeb Application Profile 1 Reference Decoder
Date: 23 April 2001
EACEM - International Association,  Diamant Building,  Bd. A. Reyers 80,  B-1030 BRUSSEL
Phone: +32 2 706 85 50   Fax: +32.2 706 85 51   E-mail: info@eacem.be

Version History
Version Date Author Description

1.0 21 Dec 2000 Alexander Wass First released version.

1.1 31 Jan 2001 Jan van Lier Add relation between logo and certification.

2.0 5 Feb 2001 Jo Vandale Adapting to the new EACEM references codes.

2.1 / r00 15 Feb 2001 Jo Vandale Adding the new EACEM template (Cover, Header, Footer, …)
3.0 / r0 1 23 April 2001 Jo Vandale EACEM Project Team 1.4 approved version.

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Contents
1 Introduction. 4

2 References. 4

3 Profile 1 Reference Decoder . 4

3.1 TeleWeb Reference Receiver. 4

3.2 TeleWeb Reference Browser . 4

Software Design. 5

3.3 Hardware Requirements. 5
4 Logo connected to Profile 1 Reference Decoder . 5
5 Contacts . 5
6 Schematic Overview . 6

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1 Introduction
TARA Systems developed on request of the TeleWeb Project a Reference Decoder (Receiver & Browser) for

TeleWeb profile 1. With the PC based GDI Display Simulator TeleWeb content can be displayed. This Profile 1

Reference Decoder is the basis for further porting activities to specific embedded hardware platforms. Further

information can be found in reference [4]

2 References
[1] EACEM TR-046: "TeleWeb Application Part 1, General Description".

[2] EACEM TR-047: "TeleWeb Application Part 2, Profile 1, Enhanced".
[3] EACEM TR-048: "TeleWeb Application Part 3, Delivery Methods".
[4] TARA Systems GMBH: "Available Documentation": Software Specifications for GDI, HTML-DOM
Implementation, Receiver, Memory Management, HTML Viewer, Application. Content Generation
Guidelines
3 Profile 1 Reference Decoder
The TeleWeb Profile 1 Reference Decoder consists of a Reference Receiver and a Reference Browser. This
Reference Decoder is platform independent and is the basis for further porting activities to specific embedded
hardware platforms. A PC based Graphical Device Interface Display Simulator is available for displaying TeleWeb
content. A TeleWeb Logo as pictured in section 4 is connected to this Reference Decoder. More information is
given in references [1], [2], [3] and [4]. Documentation can be achieved via the contact addresses in section 5.
A schematic overview of the Profile 1 Reference Decoder and GDI Display Simulator is given in section 6.
3.1 TeleWeb Reference Receiver
• Data transmission using IDL format B.
• Based on DVB Data Carousels
• FEC and CRC
• Prioritised File Database
• Pre-Filtering of pages
3.2 TeleWeb Reference Browser
• Implements a browser based on the requirements as specified in [2]
• Easy Navigation with left, right, up, down, select, colour and number keys
• Bookmark Management
• History Support
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Software Design
• Object Oriented ANSI C Design

• Platform independent
• Prepared for easy porting to embedded 16/32-bit platforms

• PC based development with slicer and display simulator

• Automatic test system
3.3 Hardware Requirements
• 16 or 32-bit controller
• 640x480 display for content
• min. 188 colours
• ~ 500 Kbytes for code (including GDI and fonts)
• >5 Mbytes RAM for database
• 1 Mbytes RAM workspace
4 Logo connected to Profile 1 Reference Decoder

5 Contacts
EACEM Brussels / Belgium Internet address: http//www.eacem.be
TARA Systems GmbH Munich / Germany Internet address: http//www.tara-systems.de
TeleWeb Project Internet address: http//www.superteletext.tv
- 5 -
6 Schematic Overview
TeleWeb Reference Receiver
IDL format B
Data
Files
File System Interface
TeleWeb Reference
File
Browser
Information
Decoding Requests
HTML
Rendering
Analyzer
Decoded Structures
Engine
Data
Object
Object Requests
Structure
Requests
Layout
Text
Display
Requests
Memory Management
Requests
Font Engine
GDI
Allocation
Calls
Requests GDI
Calls
Graphical Device Interface (GDI)
Memory Interface
GDI Display Simulator
- 6 -
GENERAL SECRETARIAT
EACEM Technical Report
TR-046-r02
Title:
TeleWeb Application Part 1, General Description
Proposed ETSI Title:
“TeleWeb Application Part 1, General Description”
Proposed ETSI keywords:
“TeleWeb, Superteletext, Browser, Enhanced, Internet, Interactive,
Profile, Overview, Teletext, HTML”
Date: 18 May 2001
EACEM - International Association,  Diamant Building,  Bd. A. Reyers 80,  B-1030 BRUSSEL
Phone: +32 2 706 85 50   Fax: +32.2 706 85 51   E-mail: info@eacem.be

History
Ver. Date Author Description
Initial split up from the original TeleWeb specification v1.6 in the TP1.4
0.1 15 Feb 2000 David Tarrant
meeting in Brussels
0.2 20 Juli 2000 Jo Vandale Adaptations during the EACEM TP1.4 and TeleWeb meeting in Rennes

0.21 8 Aug 2000 Jo Vandale Adaptations during the EACEM TP1.4 meeting in Brugge

0.22 31 Aug 2000 Jo Vandale Minor adaptations during the TeleWeb meeting in Rousset

0.3 24 Oct 2000 Jo Vandale Combining the requirement tables of profile 1.
0.4 2 Nov 2000 Jo Vandale Adding the review remarks on version 0.3 by David Tarrant.
1.0 3 Nov 2000 Jo Vandale Released version after review in the TeleWeb group.
1.9 4 Dec 2000 Jo Vandale Rework after specification changes of the steering board.
2.0 11 Dec 2000 Jo Vandale Released version after review in the Technical TeleWeb group.
2.1 31 Jan 2001 Jo Vandale Released version after minor changes during the TM of January.
3.0 5 Feb 2001 Jo Vandale Adapting to the new EACEM reference codes.
3.1 / r00 15 Feb 2001 Jo Vandale Adding the new EACEM template (Cover, Header, Footer, …)
23 April Adaptations resulting from the last Technical Meeting
4.0 / r01 Jo Vandale
2001 EACEM Project Team 1.4 approved.
Making nexTView links optional as a result of the EACEM TC support
4.1 / r02 5 May 2001 Jo Vandale
group meeting.
- 8 -
Contents
1 Scope . 12

2 References . 12

3 Definitions and abbreviations . 13

3.1 Definitions . 13

3.2 Abbreviations. 13

4 General description of TeleWeb . 14
4.1 Aims. 14
4.2 Overview . 14
4.3 OSI seven-layer model. 15
5 Documentation structure. 15
6 Application Profiles. 16
6.1 Profile 1 – Enhanced. 16
6.2 Profile 2 - Interactive TeleWeb. 17
6.3 Profile 3 – Internet TeleWeb . 17
7 Display model. 17
7.1 Display planes. 18
7.1.1 Types . 18
7.1.2 Overall sizes. 18
7.2 Usable areas. 18
7.2.1 Application Area. 19

7.2.2 Content Area. 19
7.2.3 User Interface Area. 20
7.3 Display priority. 20
8 Control model . 20
8.1 User control device . 20
8.2 Control functions . 20
8.2.1 Selecting hypertext links. 20
8.2.2 Primary link selection control. 20
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8.2.3 Mandatory functions . 20

9 Referencing. 21

10 General decoder architecture . 21

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(Blank Page)
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Intellectual Property Rights
The application described here is intended to be an open standard, free of licensing and royalty restrictions for all parties.

Apart from the Unisys patent on the LZW compression scheme used in the GIF [4] graphics format and the licensing of the
“Tiresias Screen” font from BITSTREAM [5], EACEM has not been informed of the existence of any Intellectual Property

Rights (IPR) that could be, or could become essential to the present document. However, no investigation, including IPR

searches, has been carried out. No guarantee can be given as to the existence of any IPRs that are, or may be, or may

become, essential to the present document.

The licensing options to use the Tiresias font should be discussed with BITSTREAM

[5] for each individual TeleWeb application. On a company level this licence
requirement can be already covered due to other projects like DVB, MHP,
1 Scope
This document gives a general overview of the TeleWeb application that allows Web-style text and graphics to be
broadcast to and displayed by suitable decoders.
TeleWeb services can be broadcast in a number of different ways, e.g. VBI, DVB, DAB, etc., and to a variety of decoder
types, e.g. TVs, portable decoders, PCs, etc. These transmission protocols are described in separate documents.
2 References
[4] CompuServe Incorporated: "Graphics Interchange Format, version GIF89a", July 1990.
[5] BITSTREAM is the leading developer of font technology, digital fonts, and custom typeface designs
for a wide variety of markets. Setting the standard of excellence in font technology, BITSTREAM
holds key patents covering the creation of portable fonts for the Internet. www.bitstream.com
[6] JPEG File Interchange Format Version 1.02 September 1, 1992
[7] Digital Compression and Coding of Continuous Still Images
Part 1, Requirements and Guidelines
ISO/IEC JTC1 Draft International Standard 10918-1, Nov 1991
[8] Digital Compression and Coding of Continuous Still Images
Part 2, Compliance Testing
ISO/IEC JTC1 Draft International Standard 10918-2, Dec 1991
[9] ETSI, ETS 300 472: "Digital Video Broadcasting (DVB); Specification for conveying ITU-R

System B Teletext in DVB bitstreams".
[10] ETSI, EN 301 192: "Digital Video Broadcasting (DVB); DVB specification for data broadcasting",
V1.2.1 (1999-011)
[11] ETSI, TR 101 202: "Implementation guidelines for data broadcasting", V1.1.1 (1999-02).
[12] EACEM TR-045: “TeleWeb Application Profile 1 Reference Decoder”.
[13] ETSI, EN 300 468: "Digital Video Broadcasting (DVB); Specification for Service Information (SI) in
DVB systems".
[14] EACEM TR-037: Proposal for introducing a trigger mechanism into TV transmissions.
[15] IETF RFC 1950 (1996): "ZLIB Compressed Data Format Specification version 3.3".
- 12 -
[16] ETSI TS 102 812: "Digital Video Broadcasting Multimedia Home Platform (MHP) Specification

1.1".
3 Definitions and abbreviations

3.1 Definitions
For the purposes of the present document, the following definitions apply:

Button: A part of the user interface that enables the viewer to select a page or trigger an event, etc. It may not necessarily
exist as a physical button on a remote control handset.
Independent Data Line (IDL): A standalone Teletext packet containing both control and application data. It does not form
part of a Teletext page. The packet address is either 30 or 31.
Semi-standby: A standby mode, currently known in the TV world, where the small-signal part of the set is powered to
support acquisition and signal processing. The picture tube, audio power amplifiers and other large-signal parts are not
powered. To the user the set appears to be switched off.
3.2 Abbreviations
For the purpose of the present document, the following abbreviations apply:
COP Code Of Practice
DAB Digital Audio Broadcasting
DARC DAta Radio Channel
DSM-CC Digital Storage Media Command and Control
DVB Digital Video Broadcasting
EPG Electronic Program Guide
ETSI European Telecommunication Standard Institute
FM Frequency Modulation
GIF Graphics Interchange Format
HTML Hyper Text Mark-up Language
IDL Independent Data Line
IPR Intellectual Property Rights
JPEG Joint Picture Experts Group [6][7][8]
LZW Lempel-Zif Welsh
MOT Multimedia Object Transfer (DAB Protocol)
MPEG Motion Picture Expert Group
OSI Open System Interconnection
PPP Point to Point Protocol
RGB Red Green Blue
TCP/IP Transmission Control Protocol / Internet Protocol
URL Uniform Resource Locator
VBI Vertical Blanking Interval
WAP Wireless Application Protocol
WWW World Wide Web
XHTML Extensible Hyper Text Mark-up Language
- 13 -
4 General description of TeleWeb

4.1 Aims
The aim of TeleWeb is to deliver World Wide Web-style content to the living room TV to give the viewer an enhanced

television experience without the inherent costs of connecting to the Internet via a modem and telephone line. A TeleWeb

service broadcasts data files containing text and high-definition graphics to suitable decoders. The data transmitted can be
clo sely linked to events within the accompanying TV programmes, or can be more general in nature to emulate a
traditional, but higher definition, Teletext service. Hooks are left for future expansion and enhancement.

It is the intention that TV-based decoders can be implemented in a cost-effective manner without recourse to the

technology normally associated with personal computers. In part, this is achieved by limiting the number of different types
of multimedia data that can be used within a service. By careful design of the user-interface, decoder manufacturers will be
able to offer easy to use equipment for accessing TeleWeb services without requiring the consumer to be computer literate.
In addition, they will be able to customise their products to differentiate them from those of their competitors.
The encoding and transmission scheme is designed to be as efficient and robust as possible consistent with conveying
potentially large data files via a unidirectional channel or bi-directional channel with a low or high data rate.
For example, TeleWeb data can be broadcast via Teletext packets using existing infrastructures. The TeleWeb data stream
can be encoded into independent data packets that can be transmitted with minimal interference to existing Teletext
services. In many instances it will be possible to recover otherwise wasted Teletext transmission capacity and the effect on
existing services will be negligible.
It is possible to carry multiple services from different service providers on the same television channel. The fast
transmission of services on analogue TV channels where there is no accompanying video component is also possible.
Three TeleWeb profiles are defined:
• Profile 1 - Enhanced Broadcast TeleWeb service without a return channel.
• Profile 2 - Interactive TeleWeb, extended from profile 1 with the addition of a return channel
• Profile 3 - Internet TeleWeb, extended from profile 2 offering full Internet access
Profiles 2 and 3 are designed to provide substantial backward compatibility with lower profile decoders.
4.2 Overview
A database of files is broadcast; some or all of which are captured and stored by a decoder. Certain files may be broadcast
repetitively; others may be transmitted only once when they contain real-time updates or are linked to events in the

accompanying TV programme. Each file has a set of attributes to define the file name, file type and other parameters as
required. One of these is the theme or content description. This allows a decoder to be programmed to receive only specific
information, or to exclude certain categories. This is useful where the volume of data transmitted exceeds the storage
capacity available in the decoder.
On selecting a TeleWeb service, the viewer is first presented with the home page of the service. Navigation to other pages
is via embedded links. It is possible that there may be more than one TeleWeb service on a given channel. Therefore each
service includes additional information to allow a menu of available services to be presented to the user. The user interface
is at the discretion of the decoder manufacturer, as is the provision of "bookmark" and "history" browser features.
- 14 -
4.3 OSI seven-layer model
Figure 1 shows an OSI-style seven-layer model for TeleWeb when broadcast via different delivery systems.

Layer 7: Application The TeleWeb Application

Layer 6: Presentation HTML, Text , graphics, and data files

Layer 5: Session
File attributes
Layer 4: Transport DSM-CC DSM-CC DSM-CC TCP/IP

Layer 3: Network IDL IDL DSM-CC PPP WAP MOT DARC

Layer 2: Link Teletext MPEG MPEG Serial

Layer 1: Physical VBI (1) DVB (2) DVB (3) Internet Mobile DAB FM Swift

Note 1: Any physical layer capable of carrying Teletext.
Note 2: DVB method according to reference [9].
Note 3: DVB method according to references [10] and [11].
Figure 1: OSI-style seven-layer model for different delivery systems
5 Documentation structure
Part I (this document) describes in general principles of TeleWeb and outlines the display and control models on which the
other parts are based. Part II specifies the 'Enhanced' profile and covers the format of the baseband data sent from a
headend database to decoders. Services can be delivered via a variety of methods as described in Part III.
Part IV describes the 'Interactive' profile and Part V the 'Internet' profile.
TeleWeb Documentation Structure
Part I Part II Part IV Part V
TeleWeb Application TeleWeb Application TeleWeb Application
Profile 1 Profile 2 Profile 3
ENHANCED INTERACTIVE INTERNET
TeleWeb Application Part III
Delivery Methods
Delivery Delivery
General
Protocols Profiles
Figure 2: Documentation structure
- 15 -
TeleWeb Application
General
6 Application Profiles
6.1 Profile 1 – Enhanced
This sub-clause lists the features of a TeleWeb Profile I service and a corresponding decoder. Each feature forms part of a

minimum specification for a service and/or decoder, unless marked as optional.

• Fixed content width and height (640 x 480 pixels).

• One proportional font, 5 sizes, 4 styles. The styles 'normal' is mandatory, the styles 'bold', 'italics' and 'bold &
italics' are optional.
• The “Tiresias Screen” font is used for the proportional font.
• One fixed font, 5 sizes, 4 styles. The styles 'normal' is mandatory, the styles 'bold', 'italics' and 'bold & italics' are
optional.
• Defined fixed font character cells (Height x Width in pixels).
• Support for all East and West European Latin-1 based languages.
• Minimum colour resolution of 12 bit (RGB = 444), 24 bit recommended (RGB 888).
• A minimum of 188 colours are defined in a colour palette (same as used by MHP [16] ).
• Bit-mapped graphics using the GIF and JPEG formats [4][6][7][8].
• Dithering to achieve best colour matching (optional).
• Support for full and partial transparency.
• Animation using animated GIF and marquee
• Accentuation using blink (optional).
• Display of text and graphics over video.
• The content is authored using a TeleWeb HTML.
• Additional navigation possibilities via coloured (Fastext, TOP, …) and numbered keys.
• Home page indication.
• Service identification.
• Content identification via themes.
• Age rating system based on the DVB-SI [13].
• Indication of a priority level (filtering possibilities in case of decoder memory restrictions).
• Control of primary link selection in the decoder.
• Decoder acquisition in semi-standby mode (Optional).
• 5 Mbytes of database broadcast capacity. If the broadcaster applies compression to the HTML pages and uses the
most appropriate encoding for images, more pages can be broadcasted. This broadcast capacity is divided over 2
services, a ‘Short TeleWeb Service’ (100Kbytes) and a ‘Full TeleWeb Service’ (4.9Mbytes).
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• Decoder must support one ‘Preferred’ Full TeleWeb Service.

• Decoder must support the Short TeleWeb Service on the currently tuned channel.

• Cross-linking between several services is supported through absolute TeleWeb URL’s (Optional).

• Supporting multiple Full TeleWeb Services is optional.

• Decoder support for internal links within the same TeleWeb service.

• Decoders supporting Teletext should also support links from TeleWeb to Teletext, for all other decoders this is
optional.
• Support of nexTView links from TeleWeb to nexTView (optional).
• Support of file compression based on ZLIB [15].
• Support of the trigger specification [14]
Restriction on the number of trigger streams and used transport layers will be defined in a COP.
• Decoder support for the processing of programme related information to build a TeleWeb EPG application
(Optional).
• Support for group and individual decoder addressing.
6.2 Profile 2 - Interactive TeleWeb
Decoder profile as for profile 1 adding a back channel for registration, voting, etc.
• Support of the Document Object Model and ECMAScript.
• Support of HTML Frames.
• Encryption possibilities
• HTML Forms
6.3 Profile 3 – Internet TeleWeb
As profile 2 and offering full Internet access including limited browser plug-in capabilities.

7 Display model
This section defines the features of a TeleWeb display. They are applicable to both editing stations and decoders. The
information is presented as a set of concepts to convey the general requirements. No particular method of realisation is
implied.
The behaviour of a Profile 1 display should conform to the TeleWeb reference decoder as described in [12]. The latter
should be used as a guideline to ensure conformity of all decoders in the market.
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7.1 Display planes
7.1.1 Types
The conceptual TeleWeb "Display Model" consists of up to five aligned planes, Figure 3.

The Cursor Plane does not form part of this specification. It is an option for the decoder manufacturer and might be
included as part of the user interface. If present it is assumed to have the highest display priority.

The Text/Graphics Plane is used to display all visible foreground elements of a TeleWeb service. This includes the text

and image data defined and invoked within the Body section of an HTML file.

The Background Image Plane displays an image behind the foreground elements.
The Background Colour Plane displays a single uniform colour.
The Video Plane contains the video of any accompanying TV signal. This plane has the lowest display priority.
Video Plane
Background Colour Plane
Background Image Plane
Text/Graphics Plane
Cursor Plane
Figure 3: Display planes and their priority order

7.1.2 Overall sizes
All planes are considered to be the same physical size. The Text/Graphics and Background Image planes are modelled as
720 x 576 pixels (Horizontal x Vertical) for reasons of compatibility with digital TV. The Background Colour plane can be
treated in the same way.
The Video Plane is capable of displaying the TV picture in full, regardless of the screen aspect ratio of the equipment.
7.2 Usable areas
The display area contains the TeleWeb content and the elements of the user interface. It is divided into Application,
Content and User Interface Areas.
- 18 -
An example of how the screen might be configured is shown in Figure 4. The design and contents of the user interface

areas marked as “Manufacturer defined” are not specified by the current document. They can differ depending on the

aspect ratio supported by the screen.

Limit of the
display plane
Content Area
(Service provider defined)
Manufacturer
defined
Limit of TV screen
(Application Area)
User Interface
Figure 4: Screen layout example.
7.2.1 Application Area
For information purposes only: The overscan found on most consumer TV receiving equipment has to be taken into
account. Typically this is 5% at each border. This reduces the effective area of the Text/Graphics and Background planes to
648 x 518 pixels. This "safe" area is referred to in this document as the Application Area. The Application Area will
normally be available unless the equipment is configured in a non-standard way, perhaps when the underlying and visible
4:3 format video has been manipulated to fill a 16:9 display.
7.2.2 Content Area
The Content Area is used for the display of the TeleWeb service. Its size is fixed at 640 x 480 pixels regardless of the
screen aspect ratio of the equipment. Content should be authored to take account of these limits if uniformity of display
across all decoders is considered to be essential. A decoder shall ensure that the Content Area is always visible in full
within the Application Area unless the equipment is configured in a non-standard way. Its exact position relative to the
boundaries of the Application Area is a manufacturer's option.
If a decoder is required to display content which exceeds the available space then the decoder may discard part of that
content and should initially display the upper left part.

A background image that is smaller than the background image plane should be tiled to fill the available area.
The Content Area is under the control of the TeleWeb service provider, although a decoder manufacturer may choose to
superimpose a cursor, or similar, within this area as part of the user interface. The contents of the Text/Graphics plane are
determined by the data in the text and image files. This shall be regarded as "foreground" information for the purposes of
determining display priorities. The background of an HTML table cell is also regarded as "foreground" information. The
"background" to the Content Area can consist of elements from the Background Image, Background Colour and Video
planes in any combination. The contents of the Background Image and Background Colour planes are determined by
HTML attributes. Video is displayed if the transparent colour is selected on both planes. The priority mechanism is
described in section 7.3.
Decoders with a screen aspect ratio of 16:9 can choose to render the TeleWeb content so that its 4:3 aspect ratio is
maintained. Thus a circle in an image should still appear as a circle.
Alternatively, a decoder may choose to expand the TeleWeb content to fill the available space, thus distorting the page to
some extent.
- 19 -
7.2.3 User Interface Area
In principle, the entire display area outside of the Content Area is under the control of the decoder manufacturer and can

accommodate elements of the user interface. However, to ensure visibility, the manufacturer is likely to restrict the

foreground elements of the user interface to the area lying within the Application Area.

The service provider is able to indicate when the data is best displayed without any user interface text or graphics. If this
condition is indicated (Suppress User Interface flag set), the screen areas under the control of the decoder manufacturer

should be set to display video. However, it shall be permitted to display user-interface information temporarily, for

example, in response to a command from the user or to indicate navigation options.

7.3 Display priority
The display priority order of the planes shown in Figure 3 is in the order "Cursor" down to "Video". This order is important
as the use of the 100% transparent colour feature at a given position makes visible the plane immediately below.
In general, 100% transparency should be assumed when there is no explicit definition for the colour of a particular pixel
within the Content Area. For example, in the absence of a background image file but in the presence of bgcolor=blue>, the background of the content area should be coloured blue overall.
It is possible to set an intermediate level of transparency, see TeleWeb Application Part 2. This semi-transparency only
takes effect when the lower plane is the video plane. If an intermediate level is selected elsewhere, the response of a
decoder is not defined.
8 Control model
8.1 User control device
The physical appearance of the control device and the method of interaction is not covered by this specification.
8.2 Control functions
8.2.1 Selecting hypertext links
The apparatus through which the user controls the decoder shall provide a means for choosing hypertext links displayed
within the Content Area. Conceptually, this may involve moving a cursor between the links and providing a method of
selection but other methods are not precluded (e.g. jumping highlights).

8.2.2 Primary link selection control
To provide better support for interactive applications an URL can hold extra selection information in the URL's fragment
defining the primary selected anchor in the page referenced by the URL.
8.2.3 Mandatory functions
Dedicated buttons (or their equivalent) numbered 0 to 9 shall be provided on the user control device, as shall four other
buttons (or their equivalent) coloured red, green, yellow and blue. The coloured buttons shall be grouped in that order
from left to right or top to bottom.
The function of all these buttons shall be under the control of the service provider while a TeleWeb page is displayed in
the Content Area.
Conceptually, hypertext links can be mapped to any of these buttons.
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9 Referencing
Referencing to other services, like Teletext, nexTView, Internet services, … will be provided using the standard TeleWeb

URL mechanism defined in TeleWeb Application Part 2.

These references provide a way to reuse data which is already being transmitted (or is otherwise available) within the

context of the TeleWeb application.

10 General decoder architecture

The  following drawing is an example of a TV-based Enhanced (P1) TeleWeb decoder architecture.

Sync
DECODER
alpha
Display
Memory RGB Display
Controller
Video/Data
Switch
Data
IR Remote
CPU
Tuner IR
Slicer Receiver Control
Data
Stream
Figure 5: Block diagram of a TV-based Enhanced TeleWeb Decoder

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EACEM Technical Report
TR-047-r01
Title:
TeleWeb Application Part 2 Profile 1 Enhanced
Proposed ETSI Title:
“TeleWeb Application Part 2 Profile 1 Enhanced”
Proposed ETSI keywords:
“TeleWeb, Enhanced, Superteletext, Teletext, HTML, Browser,
Profile”
Date: 23 April 2001
TP-14-00-???
EACEM PT 1.4 minutes, August 2000

History
Document history
V0.0 - V0.4 Jan. – June First drafts. Very incomplete.

V1.0 June 1998 First full draft containing HTML description and display model.

V1.1 October 1998 Updated following Brussels meeting, 13/10/98

V1.2 January 1999 Updated following Hamburg (25/11/98) and Fellbach (15/12/98) meetings
V1.3 March 1999 Updated following Southampton meeting (11/2/99)
V1.4 July 1999 Updated following Paris (23/3/99) and Fellbach (20/5/99) meetings, and
subsequent teleconferences up to 9/7/99.
V1.4.1 July 1999 Updated following Rousset meeting (19/7/99)
V1.5 December 1999 Updated following Redhill (30/9/99) and Rennes meetings (26/10/99) and
interim telephone conferences
V1.6 February 2000 Updated following Grenoble meeting (25/1/00). Profile information added
V1.7 July 2000 First splitted Version Part II
V1.8 September and Updated to reflect DTD and Style Sheet decisions
October 2000
V1.9 October 2000 Merge new HTML part and latest changes of TeleWeb group
V2.0 November 2000
Updated following the Munich Meeting (2,3/11/2000)
V2.1 December 5,
Updated following the Stuttgart Meeting (4,5/11/2000)
V2.2 8 Dec 2000 Updated according to the remarks of Manfred Schmidt
V3.0 5 Feb 2001 Adding the changes approved during the Nurnberg Technical Meeting (Jan.
2001)
Adapting to the new EACEM reference codes.
V3.1 / r00 15 Feb 2001 Adding the new EACEM template (Cover, Header, Footer, …)
V4.0 / r01 23 April 2001 Adaptations resulting from the Technical Meeting
EACEM Project Team Approved version.
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Contents
1 Scope . 31

2 References . 31

2.1 TeleWeb. 31

2.2 Character encoding . 31

2.3 HTML. 31
2.4 Image formats . 31
2.5 Analogue video broadcasting. 32
2.6 Digital video broadcasting . 32
2.7 Miscellaneous . 32
3 Definitions and abbreviations . 33
3.1 Definitions . 33
3.2 Abbreviations.
...