Rapport 3 Talking TV IRD Functional and technical specifications

Functional and technical specifications

DTT receiver with accessibility functionalities and text-to-

speech in french compatible with the french digital terrestrial

broadcast network

Version 0.1

mediatvcom – 16, rue J.-J. Rousseau – 92130 Issy-les-Moulineaux

Tél: 01 41 46 00 99

[email protected] – www.mediatvcom.com


DTT receiver with accessibility functionalities and text-to-speech in french compatible with the french terrestrial digital

broadcast network

Page 2

Produced by mediatvcom for the « Conseil supérieur de l'audiovisuel »,

16, rue Jean-Jacques Rousseau – 92130 Issy-Les-Moulineaux – +33 1 41 46 00 99 – [email protected]

SUMMARY

1 Introduction................................................................................................................................................ 5

2 Glossary ...................................................................................................................................................... 6

3 Context and purpose of this recommendations sheet................................................................................. 7

3.1 State of the accessibility for the television in France .....................................................................................7

3.2 French legislation............................................................................................................................................7

4 Recommendations for the compatibility with the french DTT network....................................................... 9

5 Recommendations to make accessible receiver ........................................................................................ 11

5.1 Design and ergonomics for the DTT receiver ...............................................................................................11

5.2 Design and ergonomics for the remote control ...........................................................................................12

5.3 Recommendation for the user manual, user guide......................................................................................14

6 Recommendations for the access to the applications ............................................................................... 16

6.1 Design and ergonomics for the user interface .............................................................................................16

6.1.1 Portal ....................................................................................................................................................16

6.1.2 Configuration........................................................................................................................................19

6.1.3 System interaction................................................................................................................................20

6.1.4 Visual signal ..........................................................................................................................................20

6.1.4.1 Sound signal......................................................................................................................................20

6.1.4.2 Speech synthesis...............................................................................................................................21

6.2 Receiver installation .....................................................................................................................................30

6.3 Access to electronic program guide .............................................................................................................31

6.4 Parental control ............................................................................................................................................32

7 Recommendations for content access....................................................................................................... 33

7.1 EIT Signaling in the french DTT network.......................................................................................................33

7.2 Subtitling.......................................................................................................................................................35



broadcast network

Page 3



7.2.1 Subtitles signaling for the french DTT broadcast network ...................................................................35

7.2.2 Accessibility for the subtitling...............................................................................................................37

7.3 Audio description .........................................................................................................................................40

7.3.1 Audio description signaling for the french DTT broadcast network.....................................................40

7.3.2 Accessibility for the audio description..................................................................................................42

7.4 Audio filtering ...............................................................................................................................................43

7.5 Advanced features........................................................................................................................................43

10 Bibliography, standards and reference documentations........................................................................... 46

11 Annexe...................................................................................................................................................... 49

FIGURES

Figure 2 - Tiresias font police intended to screen display ............................................................................................17

Figure 3 - Example of portal architecture.....................................................................................................................17

Figure 4 - « Color Contrast Analyser » window ............................................................................................................18

Figure 5 - Example of accessible portal: Tiresias font police and adapted contrast ....................................................18

Figure 6 - Example of accessible portal: presentation of the available user actions....................................................19

Figure 7 - Example of VoiceXML code ........................................................................................................................21

Figure 8 - Example of accessible EPG homepage .........................................................................................................31

Figure 9 - parental_rating_descriptor descriptor .........................................................................................................32

Figure 10 - Event_information_section descriptor.......................................................................................................33

Figure 11 - Subtitling_descriptor ..................................................................................................................................35

Figure 12 - Example of DVB subtitles with translucent banner....................................................................................37

Figure 14 – CLUT mechanism .......................................................................................................................................39

Figure 17 - HbbTV architecture ....................................................................................................................................49



broadcast network

Page 4



TABLES

Table 1 – Connectors used on television receiver........................................................................................................12

Table 2 - Keys used for accessibility functionalities......................................................................................................14

Table 3 – EPG information restitution..........................................................................................................................25

Table 4 – Summary table for TTS profile ......................................................................................................................30

Table 5 – Definition of the « rating » descriptor ..........................................................................................................32

Table 6 – Events classification for viewers users..........................................................................................................32

Table 7 – Descriptors transported in EIT table .............................................................................................................34

Table 8 - subtitling_type values....................................................................................................................................36

Table 9 – Values of the stream_content and component_type fields .........................................................................36

Table 10 - Stream_content and Component_type descriptors (broadcaster-mix) ......................................................41

Table 11 - component_type definition.........................................................................................................................42



broadcast network

Page 5



1 INTRODUCTION

The objective of this document is to define the minimum functional and technical specifications for a DTT receiver

with accessibility functionalities and text-to-speech in french compatible with the french terrestrial digital

broadcast network. It aims to be the reference document for the DTT receiver manufacturers by providing

specifications.

It addresses to all type of receivers: television and set-top-box, but more especially to all the other DTT receivers. It

doesn’t aim to define a restrictive framework of the functionalities to include in the receivers but to list the

recommendations and relevant standards, it must be consider like a “good practices guide” for the manufacturers

and suppliers.

This document also contains chapters providing the recommendations for the compatibility with the french DTT

broadcast network. The accessible receiver or universal receiver defines an equipment destined to receive the

digital television and which offers accessible functionalities for disabled and old people: text-to-speech, inclusive

design...

The technical and functional recommendations presented in this specification sheet are destined to inclusive DTT

receivers which offer these functionalities:

- Reception of DVB-T signal (EN 300 744)

- Restitution of streams with SD and HD quality

- Access to configuration menus of the receiver

- Access to essential services: program information, EPG…

- Access to accessibility services: subtitles, audio-description…

- Implementation of assistive functionalities: text-to-speech, accessible interfaces for visually impaired users

- …

The chapter on the text-to-speech is based on the DTG report with the agreement of the organization:

Implementation guidelines and recommendations for text-to-speech v1.4.

The recommendations for advanced functionalities (PVR, media center) are detailed in the chapter 7.5.



broadcast network

Page 6



2 GLOSSARY

Abbreviations Definition

AD Audio Description

CSA Conseil Supérieur de l’Audiovisuel (French audiovisual authority)

CI/CI+ Common Interface

CLUT Colour Look-Up Table

DTG Digital TV Group

DTT Digital Terrestrial Television

DVB-T Digital Video Broadcasting – Terrestrial

EIT Event Information Table

EPG Electronic Program Guide

HbbTV Hybrid Broadcast Broadband TV

HD High Definition

HDCP High-bandwidth Digital Content Protection

HDMI High Definition Multimedia Interface

IEC International Electrotechnical Commission

INTECO Instituto Nacional de Tecnologías de la comunicación

ISO International Organization for Standardization

LCN Logical Channel Number

NCAM National Center for Accessible Media

NID Network Identifier

NIT Network Information Table

ONID Original Network IDentifier

OSD On Screen Display

OTT Over-The-Top

PLS Pronunciation Lexicon Specification

PMT Program Map Table

PSI Program Specific Information

RCA Connector (audio or video)

RNIB Royal National Institute of Blind People

SD Standard Definition

SDT Service Description Table

SPDIF Sony/Philips Digital Interface

SSML Speech Synthesis Markup Language

TTS Text-To-Speech

UI User Interface

W3C World Wide Web Consortium

WAI Web Accessibility Initiative

WCAG Web Content Accessibility Guidelines



broadcast network

Page 7



3 CONTEXT AND PURPOSE OF THIS RECOMMENDATIONS SHEET

3.1 STATE OF THE ACCESSIBILITY FOR THE TELEVISION IN FRANCE

The digital TV switchover offers new solutions to improve the access to the television to the disabled people;

however, the TV receiver remains a blocking factor for the access to the audiovisual contents like subtitles and

audio-description.

The DTT receivers present on the french market provide little accessible functionalities for the elderly, the disabled

mainly for the visually impaired. In some countries like the United-Kingdom and the Spain, accessible receivers have

been marketed in the same time as the digital switchover. In this context, studies and recommendations were

written with the purpose of defining and implementing an accessible receiver.

3.2 FRENCH LEGISLATION

The legal framework aiming to enhance the accessibility to the television for the disabled exists since several years

in France. However, few laws describe the technical and functional specifications to render TV receivers accessible.

Law n°86-1067 of the September 30, 1986 concerning the subtitling:

The fifth point of the article number 28 (television services allowed for the broadcast) and the first part of the law

33-1 (others television services) defines that the CSA incorporates layouts on the accessibility of programs for deaf

and hearing impaired into the conventions on private television channels. The law imposes that the channels whose

average annual audience exceeds 2.5% of the total audience of television do have to make accessible all of their

programs (from February 12, 2010), with the exception to the advertising.

For the channels with audience lower than 2.5%, another convention established by the CSA set the proportion of

programs they have to make accessible.

Law n°86-1067 of the September 30, 1986 concerning the audio description:

This law defines that the channels which broadcast in digital and which the average annual audience exceeds 2.5%

of the total audience of television (for the public channel, this plan is specified in the scheme agreement must

propose accessible programs for peak time for blinds and visually impaired people by using adapted devices.

Public service channels

The group « France Télévisions » has implemented an audio description service from 2009 for the most important

national programs. The scheme agreement plans that the broadcast of one program with audio description service

should be available in 2012, every day on a single channel of the group.

Decree of the December 27, 2001 relating to the characteristics of the reception equipment for services

broadcasted by digital terrestrial television (Arrêté du 27 décembre 2001 relatif aux caractéristiques des

équipements de réception des services diffusés par voie hertzienne numérique terrestre )

Modified by:

- The decree of the May 26, 2005



broadcast network

Page 8



Sets the technical characteristics of the DTT receivers and especially specifies in the article 3 that “the reception

terminals […] allow to select and to display the subtitles when they are present in the signal, according to the

standard ISO/IEC 62216, especially those which are intended to the deaf and hard of hearing persons”

Decree of the December 24, 2001 relating to the digital terrestrial television and setting the characteristics of the

broadcasting signals (Arrêté du 24 décembre 2001 relatif à la télévision numérique hertzienne terrestre fixant les

caractéristiques des signaux émis )

Modified by:


- The decree of the august 25, 2010

Set the characteristics of the DTT signals broadcast in mainland and overseas France.

Quality charter for the subtitling destined for the hard of hearing and deaf people (Charte de qualité pour le

sous-titrage à destination des personnes sourdes ou malentendantes)

Define 16 criteria to improve the subtitling for the deaf and hard of hearing.

Article 34-2 of the September 30, 1986, paragraph III (Article 34-2 de la loi du 30 septembre 1986, alinéa III)

« Services distributors must make available services for the deaf, visual disabled, hard of hearing and blind persons

with their television services. The necessary technical dispositions are dependent upon. »

Law n°2007-309 of the March 5, 2007 relating to the modernization of the audiovisual broadcast and the

television of the future (Loi n° 2007-309 du 5 mars 2007 relative à la modernisation de la diffusion audiovisuelle

et à la télévision du futur.)

“From 1st December 2012, all the TVs for individuals which receive digital terrestrial television services, when they

are sold by a professional to an individual, must include an adapter that allows the reception of all the free

programs of terrestrial digital television in high definition and standard definition.”

“From 1st December 2012, all the set top boxes for individuals and receiving services for digital terrestrial

television, when they are sold by a professional to an individual, must include an adapter that allows the reception

of all the free programs of terrestrial digital television in high definition and standard definition.”



broadcast network

Page 9



4 RECOMMENDATIONS FOR THE COMPATIBILITY WITH THE FRENCH DTT NETWORK

The television terminal must be compatible with the signals broadcast on the french DTT network. Those signals are

conform to the recommendations of the CSA « Services et profil de signalisation pour la diffusion de la TV

numérique de terre métropolitaine et ultramarine version 3.2 juillet 2010 ».

Furthermore the decree of the December 27, 2001 (modified version) relating to the characteristics of the

reception equipment for services broadcast digital over-the-air television defines that the receivers are conform

with the ISO/IEC 62216 standard and allows the reception of the DTT signals (transmitted in isofrequency and

multifrequency network) specified in the decree of the December 24th 2001 relating to the digital terrestrial

television.

The DTT receiver shall be in keeping with the ISO/IEC 62216 and supports:

- The signal shall be broadcast in accordance with the DVB-T standard (EN 300 744)

- A NIT table splits into several sections with a minimal temporal space between two sections which is

equals to 25 ms. The document « Méthodologie de test de non-conformité à la segmentation de la table

NIT des récepteurs TNT vendus aux consommateurs » contains information used to valid that DTT receiver

can support the NIT segmentation.

- The descriptor Logical_Channel_Number_Descriptor which allows numbering of the services with this

descriptor as it is specified in the terminal decree (article 2, paragraph 3)

- The descriptor HD_Logical_Channel_Number_Descriptor which allows the substitution of the LCN for the

SD and HD services.

- A second repetition of the Logical_Channel_Number_Descriptor loop.

- The NIT version number which allows the automatic identification of the modifications on the services

plan, the apparition of new services and allows therefore a new services numbering for the different

multiplex.

- The network identifiers NId = 0NId = 0x20FA which are assigned to the France and which allows receiver to

identify the french network.

- The video components coded with MPEG-2 (ISO/IEC 13818-2).

- The video components coded with MPEG-4 (ISO/IEC 14496-10).

- The descriptor service_type 0x01 (MPEG-2 SD, MPEG-4 SD, MPEG-4 HD), 0x16 (MPEG-4 SD), 0x19 (MPEG-4

HD).

- The video formats 4:3 and 16:9.

- The audio components coded with MPEG-1 Layer II (ISO/IEC 13818-3).

- The audio components coded with AC3 and E_AC3, especially when the receiver supports HD.

- The language code « qaa » contents in the ISO_639_language_descriptor and which means “original

version”.

- The language code « qad » contents in the ISO_639_language_descriptor and which means “audio-

description”



broadcast network

Page 10



Furthermore, it is recommended that the implementation of the DTT receiver takes notice of the recommendations

on the loudness levels for each output connector (analogic, SPDIF, HDMI) and especially in the case of the audio-

description restitution contents according to the EBU-Tech 3344 (Practical guidelines for distribution systems in

accordance with EBU R 128) which is defines by the European Broadcasting Union.



broadcast network

Page 11



5 RECOMMENDATIONS TO MAKE ACCESSIBLE RECEIVER

The accessible ergonomic or universal design means that the implementation of a system or a service takes into

account all the diversity of user needs and the capabilities even. The purpose is to design solutions for the largest

number of users.

This approach for implementation takes notice of the following recommendations:

- It takes into account the capacities of all the users without discrimination.

- It brings flexibility in order to allow users to adapt the solution to their needs

- Implement a solution or a service the most simple and intuitive as possible for the user.

In the context of building accessible DTT receiver, it means to design the system which can be used by the largest

number of people taking into account the differences of each user: disability, technical knowledge… the receivers

shall not force high cognitive demands on the users; it must stay easy to use.

5.1 DESIGN AND ERGONOMICS FOR THE DTT RECEIVER

The DTT television receiver can be a television set or a set-top-box connected to a television set. The use and the

implementation shall be easy. The specific uses of each category of users shall be taken into consideration.

The implementation of the accessible receiver shall follow the recommendations described in these documents:

TR (Technical report) 22411 Ergonomics data and guidelines for the application of ISO/IEC Guide 71 to products

and services to address the needs of older persons and persons with disabilities

- Contains general recommendations on the universal ergonomic for the services and the solutions aimed at

the old and the disabled people.

9241-20 Ergonomics of human-system interaction — Part 20: Accessibility guidelines for information/

communication technology (ICT) equipment and services

- Contains recommendations on the universal ergonomic for human interfaces in the case of the ICT services

and solutions aimed at the old and the disabled people.

TR (Technical report) 29138-1 Information technology — Accessibility considerations for people with disabilities

— Part 1: User needs summary

- Contains information on the user’s needs for the ICT services and the products.

IEC/TR 62678 ed1.0 Audio, video and multimedia systems and equipment activities and considerations related to

accessibility and usability - 2010-10-05

- Contains a complete list of the information sources on the accessibility. There is also a synthesis of the

needs for the disabled people.

The main points that improve the accessibility for DTT receiver are:

- Accessible connectors: large space between each audio/video output

- Connectors easy to distinguish from all others: color, relief…

- Visual interface on the face of the DTT receiver: digital screen, ON/OFF LED

- Audio Jack connector 3,5 mm on the face of the DTT receiver

- Infrared remote control or radio remote control with a large operating angle.



broadcast network

Page 12



List of useable connectors:

Connector type Remarks

Scart connector Forecast at least one connector for the

video recorder

USB connector USB 2.0 – Used for Media Center and PVR

functionalities

RCA connectors

HDMI connector

(with HDCP)

HDMI 1.0/1.2/1.3, HDCP 1.1/1.3

Optical or coaxial

audio SPDIF

connector

Headphone jack

connector

Smart card reader Access to crypted contents

Coaxial cable

connectors

Common Interface Conditional-access module (DVB CI or DVB

CI+)

Table 1 – Connectors used on television receiver

The induction loop system helps deaf people to hear sounds more clearly by reducing or cutting out background

noise. This type of equipment can be connected to the scart or the headphone jack output. Receiver manufacturer

shall ensure that the audio is well streamed for the loop system; anymore it shall check the receiver doesn’t disrupt

the reception due to magnetic interference.

5.2 DESIGN AND ERGONOMICS FOR THE REMOTE CONTROL

Currently, no standard defines the elements that shall be implemented to make a remote control accessible.

However, the DTG: UK Digital TV Usability and Accessibility Guidelines recommendations, including Text to Speech

(chapter 1) contains essential points for accessible remote control:

1. The dimensions of the remote control must allow easy handling, it is necessary to promote such a large

width.

2. The number of keys must be limited.

3. The remote control shall have large and spaced keys.

4. The remote control shall have visual markers for all keys: texts and symbols. A special attention should be

provided to the quality of the markers which must last. The manufacturer shall improve the keys

readability, for example by used backlight on the remote control.

5. The texts shall be readable for everybody : high fonts and adapted contrast.

6. The remote control shall offer large amplitude for the emission of the infrared signal to the receiver. A

radio-frequency-capable remote control should be used in order to make it easier for the receiver to work.

7. The remote control shall have a shape or tactile markers to allow visual disabled and blind users to

distinguish the keys. The landmark on the key « 5 » (ETSI ES 201 381) is necessary same as the audio

description access key.



broadcast network

Page 13



8. The remote control should have a key allowed to turn on and turn off the television set (in the case that

the receiver is a set-top-box).

9. The choice of materials is important, those which have a pleasant feel must be promoted (avoid abrasive

surface) as well as materials that offer a good grip in the hand.

10. The remote control shall emit a beep, a visual signal or vibration to notify to user a key was pressed and

was received by the television set. This facility shall be switched off by the user.

11. The keys « OK » and « Return» shall have a position that allows an easier location.

12. If colors keys are used, important contrast and other elements of differentiation will be implemented.

13. The television receiver should be offered with two designs of remote controls:

- The first one should be simple with few keys

- The second one should be more sophisticated, with more keys and destined to the disabled

people.

14. The keys of the remote control shall be assorted by functionalities in separate areas to make their

locations easier.

The follow scheme gives an overview keys grouping:

Figure 1 - Example of accessible remote control

Keys associated to video recorder feature

Colors keys used for the interactive applications: HbbTV….

Accessibility functionalities (subtitles and audio description access, TTS)

Information key, menu access key, EPG key…

Navigation keys and CHP+/CHP-, V+/V-…

Numerical keyboard

On/Off receiver set-top-box or television



broadcast network

Page 14



15. The follow keys shall be available on the remote control to turn on and turn off the main accessible

functionalities.

Features Recommendation Remarks

Activation and deactivation of the

subtitles (DVB SUB)

Mandatory Direct access to DVB_Subtitling not to

DVB_teletext.


audio description

Mandatory


text-to-speech on the receiver

Mandatory

”Help” key to access to the help

menu

Mandatory Allow the user to know where he is:

- Provide information about the visualized event

(Channel name, duration of the event…) or the

name of the menu pages.

- Provide the content of a page or a pop up.

Standby key for the television set

(in the case that the receiver is a

set-top-box)

Recommended

Table 2 - Keys used for accessibility functionalities

5.3 RECOMMENDATION FOR THE USER MANUAL, USER GUIDE

The user manual or user guide is the document that describes the installation and the functioning of the DTT

receiver. It should be accessible and comprehensible for the largest number of users. This document should be

offered in different accessible formats. These recommendations define the best practices of implementation:

1. The user guide shall be written with a font police adapted for visual disabled people, the use of TIRESIAS LPfont

is recommended because it makes easier the readability. High size type is recommended, for example choose

16pt as minimum.

ABCDEF… abcdef… 12345678…

2. The user guide shall contain schemes to inform the user about the receiver connections to the other

equipment: television, digital recorder, headphones…

3. The document shall describe the functionalities with precision.

4. The used vocabulary shall be simple and clear, the use of technical terms should be avoided.

5. The receiver should be offered with a quick start guide of one or two pages, which allows the fast installation

of the receiver. This guide should contain the following points:

a. List of the elements provided with the receiver.

b. Schemes or pictures to illustrate the connection of the receiver (plug connectors, connection to the

antenna …).

c. Presentation of the remote control keys.

d. Presentation of the receiver installation steps.

6. The user guide should use screenshots and photos as illustrations.

TIRESIAS LPfont - Size 16



broadcast network

Page 15



7. The user guide should contain colors and symbols.

8. The user guide shall be available in the form of website and downloading files (accessible format):

1. A PDF file which follows the recommendations of the AcceDe PDF (http://www.pdf-accessible.com)

2. A text file (Word, odt…) which follows the recommendations of the « European Blind Union »

3. A website that follows the W3C accessibility standards:

- Web Content Accessibility Guidelines (WCAG) 2.0

- User Agent Accessibility Guidelines (UAAG) 1.0

9. The user guide should be available in a Braille format.

10. The user guide shall be available in audio format. If necessary, the file could be downloaded on a website.

11. The user guide should be contains special chapters for disabled. For example, a chapter should present the

functionalities aim to the blind and the visual disabled users (TTS activation, audio description activation,

contrast setting…).

12. Some user guides chapters should be also available directly from the receiver embedded portal, it make easier

the access to information.

13. The necessary accessories shall be furnished with the receiver: cables, batteries…



broadcast network

Page 16



6 RECOMMENDATIONS FOR THE ACCESS TO THE APPLICATIONS

6.1 DESIGN AND ERGONOMICS FOR THE USER INTERFACE

The user interface is composed of graphic elements which are displayed on the television screen and used to

inform the user about the system status and also to give information: displayed event, event summary, EPG… This

interface is organized with pages associated to the menus: audio and video settings, program guide… and contains

selectable elements to navigate, configure the receiver and/or launch actions.

6.1.1 PORTAL

The TV portal offers a front door on a wide range of features and services. It allows the user to access receiver and

service information; furthermore it allows to set the receiver according the needs and the usage of the user. It shall

be implemented in order to make easier the understanding of the displayed information and the access to the

menus.

The project « GUIDE » (Gentle User interfaces for elderly people) aims to create a software framework and design

tools to create interfaces intended for elders and disabled people. The software frameworks could be directly

integrated in the receiver middleware to implement accessible functionalities.

No standard defines the elements that are necessary to implement in order to create accessible portal. However,

the DTG wrote a document that shall be used as reference for the manufacturers and which contains a list of

recommendations for accessible receiver: UK Digital TV Usability and Accessibility Guidelines, including Text to

Speech. The chapter 4 contains the recommendations for an accessible user interface. Anymore, the Web

Accessibility Initiative (WAI) which is part of W3C defined recommendations to make accessible websites, these

recommendations shall be taken into account and adapted to TV portal: Web Content Accessibility Guidelines

(WCAG) 2.0.

1. The text shall be displayed on a uniform color background. Background with pictures and other textures

should be avoided.

2. The text shall be as much as possible in text format instead be inserted in a picture. It necessary to keep an

acceptable resolution when the user increases the text size.

3. The symbols contained in the portal shall respect the standard ISO 7001: Public Information Symbols.

4. Each word, group of words contained in the menus and sub menus shall start with a capital letter.

5. The use of large line spacing shall be privileged.

6. The portal shall not contain text with bold and italic letters, words.

7. The number shall be display with the Arabic format: 1, 2, 3…

8. The use of page scrolling shall be limited. The keys « up » and « down » are recommended for the page

scrolling in the case of long text.

9. The name of each menu shall be clearly display.

10. Portal elements (sub-menus, parameters) that are selectable by the user shall be preceded by number.



broadcast network

Page 17



11. The display text shall use a police font adapted to visual disabilities as Sans Serif, Verdana and Arial.

Remark: The police font Tiresias developed by the RNIB for the display on the digital screens is

recommended with a size font of 24 lines of pixels for the chapter name and 18 lines for the text.

Figure 2 - Tiresias font police intended to screen display

12. The text shall be left aligned.

13. The menu tree shall be limited to three levels.

14. Figure 3 - Example of portal architecture

15. The choice of the colors and contrast of the interface shall take into account the specific needs of the

visual disabled people. The colors shall give readability and inform user of the cursor position.

Choosing a high contrast can distort the text for some users. The combination between color with high

contrast and absolute black is not recommended. White and black in their sheer form (RGB: 255, 255, 255

and RGB: 0, 0, 0) are also not recommended. The saturation must be limited to 85%.

Several visual disabilities exist and the implementation of a mechanism allowing the user to change the

contrast is necessary to adapt the readability of each one.

The software « Color Contrast Analyser » developed by the association « Vision Australia » defines the

readability of a webpage on television set and text includes in picture. Information about the software and

the binary are available in this link: http://www.visionaustralia.org.au/info.aspx?page=961



broadcast network

Page 18



Figure 4 - « Color Contrast Analyser » window

In general, the following contrasts are recommended in the most cases:

- Dark background and light colors for the text displayed: white, yellow on

- Black on white background also offers a good contrast.

Figure 5 - Example of accessible portal: Tiresias font police and adapted contrast

RGB: 255, 255, 204

RGB: 255, 255, 128

RGB: 0, 0, 0

RGB: 0, 0, 128



broadcast network

Page 19



16. Each page shall contain indications on actions available on this page. These ones must be associated to the

remote control keys.

Figure 6 - Example of accessible portal: presentation of the available user actions

17. Simple vocabulary shall be employed; therefore technological vocabulary shall be avoided.

18. The user current position in the menu shall be clearly indicated (window, highlight…).

19. Menus and submenus shall be logically organized.

20. The portal should be available in high definition in order to offer the best readability. In general, the user

should choose the most adapted resolution for the used screen.

21. Colors shall not be used like the only way to communicate important information; other visual elements

shall be implemented: window, highlight, contrast…

6.1.2 CONFIGURATION

The receiver configuration shall allow the user to adapt setting to his needs. The standard ISO/IEC 24786:2009

Information technology -- User interfaces -- Accessible user interface for accessibility settings contains the

recommendations that define the elements to implement in the case of the user interface setting. Manufacturer

shall follow the recommendations define in this documents.

1. User shall be able to choose contrasts and colors use by the portal.

2. The receiver shall give to the user the means for sectioning, classing and filtering the channels of the

services plan in order to edit a favourite channels list for example.



broadcast network

Page 20



3. Give an overview of new receiver setting when the user wants to change a value. For example, when the

user wants to change the contrast, it should be possible to see the result without valid the choice.

4. The user shall choose the police font size. Three size profiles (normal, big and very big) should be offered.

It should be possible to change the police font (only if the receiver implements this feature).

5. The user shall choose the output video aspect ratio: 4:3 or 16:9.

Moreover, it should not be possible to switch off the sound with the key « V- », the key « MUTE » should be the

only key allowing this action. It allows the user to know the system state when a service is displayed.

6.1.3 SYSTEM INTERACTION

The system has many facilities to interact with the user. Those that shall be implemented for accessible receiver are

defined in this chapter.

They allow the user to access to the following information:

- System alerts (loss of signal, access to locked contents …).

- Navigation information (name of the menus and other display elements).

- Information contain in the EPG

6.1.4 VISUAL SIGNAL

The two most common ways to share information are:

- Display a « pop-up window ».

- Display a new page.

The visual messages shall respect the following recommendations in order to be accessible for the largest number

of users:

1. Only display the relevant information: bugs, alerts…

2. Associate the message with a sound signal.

3. Give information to the user about the means to resolve abnormal situations (check connectors…).

6.1.4.1 SOUND SIGNAL

The sound signal is a good way that should be used to give information and alerts to the user for the currents cases:

1. When system events are displayed and vocalized with the TTS system, the sound signal shall be used to inform

the user about the actions which are in progress: menu or channel change…

2. When alert pop-up are displayed, the system shall play sound signal.



broadcast network

Page 21



3. When selected service is broadcasted with audio description, the system shall play sound signal.

6.1.4.2 SPEECH SYNTHESIS

The speech synthesis is based on computer sound synthesis technique that creates artificial speech from any text.

Pieces of recorded speech are used to create synthesized speech. In general, speech synthesis is composed by

elementary sound database and rendering engine. The quality is dependent on the processor and memory

resources available: RAM, ROM and Flash memory. For information, the current solution’s needs are following

resources:

- 2.5 Mo of RAM for the application execution.

- 3.5 Mo of memory for the record of one language library.

The text-to-speech solutions could use markup languages to define the text for the vocalization. Most of languages

are based on the Voice Extensible Markup Language or VoiceXML (3.0 - W3C Working Draft 16 December 2010) :

- Pronunciation Lexicon Specification (PLS) Version 1.0 - W3C Recommendation – 2008

- Speech Synthesis Markup Language (SSML) Version 1.0 - W3C Recommendation 7 September 2004

- SABLE (version 1.0)

- …

<vxml version="2.0 » xmlns="http://www.w3.org/2001/vxml">

<form>

<block>

<prompt>

Bonjour !

</prompt>

</block>

</form>

</vxml>

Figure 7 - Example of VoiceXML code

Currently, many solutions with free software license and exclusive rights are implemented for embedded systems

as DTT receiver. They distinguish themselves by their size and the quality of the synthetized voice. Some solutions

allow the user to choose between male or female voices. The solution could be integrated directly in a television

receiver or in an external system.

In the case of the television receiver, the speech synthesis is used to vocalize the displayed text to user. For this,

television set speakers or receiver-connected headphones are used.

No standard defines how synthesis system shall be integrated on television receiver. For information, IEC

workgroup is currently working on: Text-to-Speech Functionality for Television - General requirements, Réf.

62731 Ed. 1.0

The implementation of text-to-speech solution shall follow the DTG recommendations: Implementation guidelines

and recommendations for text-to-speech v1.4. Currently, it is the only document which contains

recommendations that define the functioning of the vocalization for digital television receiver. The following

chapters 6.1.3.2.1, 6.1.3.2.2, 6.1.3.2.3 and 6.1.3.2.4 come from these recommendations.



broadcast network

Page 22



The DTG document defines three profiles for the speech synthesis. Each one defines a set of features:

1. Main profile

2. Enhanced profile

3. Full profile

An accessible television receiver that contains speech synthesis solution shall follow the functional

recommendations define in the « Main » profile. They are the minimum functionalities to implement. Others

profiles specify supplementary functionality levels.

6.1.4.2.1 FUNCTIONAL SPECIFICATIONS

This chapter contains the information presented in the DTG’s Implementation guidelines and recommendations

for text-to-speech v1.4. It corresponds with the chapter 2.1 of the original document.

The following functional guidelines describe how the text-to-speech solution shall be implemented on television

receiver:

1. All relevant information on the screen, as soon as it is displayed, shall be accessible to the user as audio

information. Relevant information includes any text and icons that are providing useful information to the user. The

following are excluded from this requirement:

a. Anything embedded in the broadcast video (e.g. news ticker).

b. Subtitles.

d. Text or graphics that are included for cosmetic reasons only (e.g. company logo).

e. Update to the display of the current time and date.

2. Audio information shall be ordered to present the most important items first. Important information shall be

presented as soon as it is displayed; other information (e.g. navigation information) may be presented only upon

request.

3. Audio information (as described above) or feedback (e.g. a key click sound) shall be provided after the user has

pressed a key (front panel or remote control). This should be within a maximum of three seconds. This is not

essential when the result of the key action is to put the receiver into a non-active state (e.g. going into standby or

power off state). However, this is essential when entering an active state (e.g. coming out of standby or power on

state).

4. Audio information shall be announced in response to the user pressing any front panel buttons. The audio

information shall be the same as when the equivalent remote control button is pressed.

5. The users shall be provided with audio information so that they always know where they are within the receiver

UI. For example, the title of a menu screen should be announced following a transition to a new screen.

6. It should be possible to cancel the presentation of the audio information currently playing with a user action, for

example by using a dedicated ‘shut up’ key.

7. If new information is displayed that takes priority over any currently playing audio information, the presentation

of the currently playing information shall be cancelled to allow the presentation of the new audio information. For

example, this could be in response to a user action like moving through the EPG or changing service.



broadcast network

Page 23



8. Notwithstanding the above points, receivers are allowed to block the cancellation of some audio information,

e.g. warnings about the result of invoking a factory reset feature.

9. It shall be possible to repeat the currently playing, or previously played (if none currently playing) audio

information. There should be a dedicated ‘repeat’ key to do this, which may also add additional audio information,

e.g. navigation information for the current screen. If the audio information has changed since the last presentation

(e.g. time display), the new audio information shall be presented rather than a simple repeat of the previous

information.

10. There shall be a way to turn Text to Speech on and off. There should be a dedicated key to do this.

11. A description of those buttons which are essential for the user to interact with the user interface within the

current context (but not necessarily displayed on screen) shall be included in the audio information. It is acceptable

that this information is included in the “additional information”.

12. When a progress bar or a changing numeric indicator (e.g. percent complete) or similar is displayed, it is not

required to provide audio information every time the screen is updated. However, its condition shall be accessible.

If the user interface design is such that the user is waiting for something to complete and the completeness is

indicated by this bar or indicator, audio information on the status shall be provided regularly.

13. For any delay in receiver operation of ten seconds or more for which there is no onscreen notification, some

form of audio feedback shall be provided, e.g. beeps or TTS audio information (if available).

15. The language of the audio information shall by default be the same as that set by the user for the receiver UI,

except for any text that has a different language provided with it. If the TTS engine does not support the signalled

language, it shall not attempt to pronounce the text, and shall indicate via audio information that the signalled

language is not supported.

16. Receivers may provide audio information that is not a literal reading of the visual information on the display, as

long as the equivalent meaning is conveyed to the user.

17. When the user mutes the audio, no further audio information shall be presented, except for feedback from

pressing the mute key. Audio beeps (e.g. from remote) will continue to be audible after pressing the mute key.

18. All static words (as opposed to dynamic content) should be pronounced correctly.

6.1.4.2.2 TECHNICAL SPECIFICATIONS

This chapter contains the information presented in the DTG’s Implementation guidelines and recommendations

for text-to-speech v1.4. It corresponds with the chapter 2.2 of the original document.

The follow functional guidelines describe how the text-to-speech setting shall be implemented on television

receiver:

1. The user should be able to change the amount of audio information (e.g. amount of help given within

prompts). It should be possible to at least set two levels of verbosity, one for beginners and one for expert

users.

2. The user shall be able to adjust the volume of the audio information, and the TTS engine shall announce

the change at the new volume level.

3. The user should be able to adjust the speed and where applicable other characteristics of the audio

information such as pitch and TTS voice type.



broadcast network

Page 24



6.1.4.2.3 IMPLEMENTATION RECOMMANDATIONS

This chapter contains the information which is presented in the DTG’s Implementation guidelines and

recommendations for text-to-speech v1.4. It corresponds with the chapter 3 of the original document.

The follow recommendations define how the text-to-speech setting shall be implemented on television receiver

and describe the specific scenarios for the most important receiver functionalities: Portal, EPG…

Generic guidelines:

1. When a screen title will help the understanding of the user, that title should be spoken, even if not visible

on the screen.

2. All audio information for screen options should not be unambiguous and make sense on its own.

3. For empty screens or lists (e.g. favourites lists with no favourites, media with no files), suitable audio

information will be provided, even if not visually presented.

4. Where a pop-up notification is presented on-screen, an unambiguous announcement should be made to

let the user know that a pop-up has been presented, before announcing the contents of the pop-up.

5. For complex screens containing large amounts of information (e.g. diagnostics) there should be a way for

the user to access the information in manageable sections.

6. Abbreviated words should be spoken in full by the TTS engine.

7. All numbers should be spoken in a suited manner suited to the context, e.g. as natural numbers, ordinals

or digit-by-digit.

8. Location -based content should be fully understandable in the context of other items on the screen. In this

event these other items should be output as TTS data. For example, in a grid based EPG the highlighter and

its (x,y) position within the grid also represents information. Therefore, the contents of the x-axis and y-

axis at the position of the highlighter should also be output, such as date/time & LCN.

Menus

1. When initially displaying a menu-style screen, the total number of menu entries and the currently

highlighted entry will be spoken.

2. All menu entries will be numbered and this number spoken with the menu corresponding entry. This does

not imply that the number is visible. The menu entry should be selectable with the numeric keys.

3. Possible options against a menu entry will follow rules 1 and 2 above.

Electronic Program Guide

In most cases, the implementation of the Electronic Program Guide consists of two pages: The first is the main page

that contains a list of services for each channel and the second is the individual page that contains service

description. The system gives information about the selected service when the user accede these pages. Program

information that came from EPG is also returned when the user accedes to new channel or when he uses the

information key from a visualized program. The follow table gives the list of the information that shall be vocalized

when the user selects an item of these pages:



broadcast network

Page 25



Information to be returned Main page Access to new service Selection of new event

Screen information e.g. screen title, screen

type (list versus grid view).

��

The Audio description beep, if applicable. ��

Channel number (LCN). ��

Service name. ��

Event title. ��

Start time including the date if not the

same as the current date. The name of the

day (e.g. Wednesday) or context dependent

references (e.g. tomorrow) are acceptable

as long as they are unambiguous.

��

End time or duration. ��

Audio description, if applicable (EIT data). In

this case, it is not AD Beep, but a message

spoken.

��

Subtitles, if applicable. ��

Recording and reminder notifications (set to

record/recording/recorded) if applicable.

��

Event synopsis. ��

Parental control lock status if set. ��

Information about the event classification

(Code that is contained in the

parental_rating_descriptor descriptor).

��

Information about page navigation. ��

Table 3 – EPG information restitution

Zapping banner

When changing channel, the receiver display zapping banner that contains event information (EIT data). The text-

to-speech shall give follow information:

1. Audio description beep, if applicable

2. Logical channel/service number, if displayed

3. Service name

4. Event title, if displayed

5. Event start time, if displayed

6. Event end time or duration, if displayed

Record menu

When record is started from the EPG pages or a visualized service, the receiver shall give the follow information:

1. Event title of the event to be recorded.

When accessing scheduled recordings, the receiver will state the following information:

1. Audio description beep if applicable



broadcast network

Page 26



2. Event title

3. Logical channel/service number

4. Service name

5. Recording start time

6. Recording end time

7. Date or Day. This may be in the form of a date such as “DD/MM” or “today, tomorrow, DD/MM” or

“Wednesday 3rd November”.

The order of the items above can be specified by the manufacturer. It is strongly recommended that the event title

is given first after the AD beep.

Menu that contains the list of event records

When accessing recorded events, the receiver will state the following information:

1. Audio description beep, if applicable

2. Event title

3. Recording status / date recorded e.g. “currently recording” or date shown as e.g. “DD/MM/YYYY” or “1st

November 2009”.

4. Duration of recording

5. Logical Channel/Service Number

6. Service Name

7. Recording protected, if applicable

8. Recording locked, if recorded on a locked channel

It is recommended that the above order be followed, however, the order can be as specified by the manufacturer

with the strong recommendation that the event title is given first after the AD beep.

In the case of the events which belong to V category (according to CSA code), the receiver shall implement the

necessary protection systems in order to lock contents (parental code…) for the young public.



broadcast network

Page 27



6.1.4.2.4 VOCALISATION PROFILES

This chapter contains the information which is presented in the DTG’s Implementation guidelines and

recommendations for text-to-speech v1.4. It corresponds with the chapter 4 of the original document.

Three profiles are defined and described in this document: Main, Enhanced and Full profile. Each profile defines the

functional edge that shall be implemented; the first one defines the minimum functionalities that shall be available

on the television receiver:

Main profile

Viewing and changing services

1. The user shall be informed of what event is on now and should be informed of what event is on next

(where available) . This shall include LCN, service name, event title, start and end time or duration.

2. The user shall be able to access the synopsis of the current event title and should be able to access

the synopsis of the next event title.

3. The user shall be informed of the number button that they have pressed (on changing service).

4. The user shall be informed of the service that they are viewing.

5. The user shall be informed of the service that they have changed to. This shall include LCN, service

name, event title, start and end time.

6. The user should be informed whether an event title has subtitles and/or AD is available (AD only has

to be announced if there is not audible notification - beep).

7. The user shall be able to navigate the service list (where available).

8. The user shall be informed if a service that has been tuned to is not available due to PIN control or

tuning issues.

Menus

1. The user shall be informed of any warnings and notifications, such as re-tuning or PIN control.

2. The user shall be able to navigate the menus i.e. the following shall be available as audio information:

entering a menu, exiting a menu, moving between and selecting items and change a setting in the

menu, as appropriate.

3. The user shall be informed of a change of setting.

PVR

1. For receivers that support PVR functionality the following buttons shall be announced when pressed:

Pause, Playback, Rewind, Fast Forward, Stop and Record.

Additional

1. The user shall be informed of the current status when the AD, subtitles, TTS and mute buttons are

pressed on the remote (subject to availability).



broadcast network

Page 28



2. The user shall be able to find out the current time where available.

3. The user shall be informed when the receiver has been switched to standby.

4. The user shall be informed of what service is on now when the receiver leaves standby. This shall

include service name and event title.

5. The user shall be informed of action in progress.

6. The user shall be able to alter the volume of the TTS.

7. The TTS should be off as a factory default but shall be temporarily on for set-up and factory reset.

8. The user shall be informed if the TTS audio information is not available when the user enters a function

or feature for which TTS audio information is not supported.

Enhanced profile

The features defined in the main profile are included in the enhanced profile.


1. The user shall be informed of what event is on now and next (where available). This shall include LCN,

service name, event title, start and end time or duration.

2. The user shall be able to access the synopsis of the current and next event titles.

3. The user shall be able to browse the EPG and find information on specific event titles.

4. The user shall be informed of an event start time.

5. The user shall be informed whether an event title has subtitles and/or AD are available (AD only has to

be announced if there is not audible notification - beep).

6. The user shall be able to access the synopsis for all event titles.

7. The user shall be informed of any filters that have been applied to the EPG, e.g. TV/radio.

8. The user shall be informed of a service lock or pay-TV service when in the EPG or service list (if

available).

Menus

1. The user shall be informed of the number of items available within menus.

Additional

1. The user shall be able to access any recorded events.

2. The TTS should be off as a factory default but shall be on for set-up and factory reset.

3. The user shall be able to alter the speed of the TTS

4. The user shall be able to alter the level of verbosity of the TTS

5. The user should be able to alter the pitch of the TTS



broadcast network

Page 29



6. The user should be able to alter the TTS voice type

Full profile

The features defined in the main and enhanced profiles are included in the full profile.


1. The user shall be able to access to advanced services (HbbTV…)

Additional

1. The user shall be able to alter the pitch of the TTS

2. The user shall be able to alter the TTS voice type

The follow table gives a synthesis of functionalities associated with each TTS profiles.

Guidelines Main

profile

Enhanced

profile

Full

Profile

Restitution of information about present events (not

summary)

��

Restitution of event summary ��

Restitution of the pressed keys ��

Restitution of the name of the visualised channel ��

Restitution of the channel name for zapping ��

Restitution of information about subtitles and audio

description availability (Beep or vocalization)

��

(if possible)

��

Restitution of information about the event list navigation ��

Announcement when an event is locked ��

Restitution of the receiver state notification ��

Restitution of information about the portal navigation ��

Restitution of information about receiver change settings ��

Restitution of functionalities for the video recorder ��

Restitution of the time ��

Announcement when the receiver is switched to standby ��

Restitution of information about the present event after

standby

��

Restitution of information about the system tasks

progress

��

Modification of the sound level ��

Vocalization temporally available for the receiver

installation

��

Announcement when the vocalization is not available for

action

��

Restitution of information about the present and next

events (not summary)

��

(if possible)

��

Activation of the vocalization for installation and reset

phases

��

Restitution of summary for the present and next events ��

Restitution of EPG page in order to select an event ��

Restitution of event start time ��

Restitution of event summary ��

Restitution of information about events filter ��



broadcast network

Page 30



Restitution of information about locked events

��

Restitution of information about items display in each

page of the menu

��

Restitution of information about the recorded events ��

Setting of the speed for the synthetic speech ��

Setting of the verbosity for the synthetic speech ��

Setting of the pitch for the synthetic speech ��

(if possible)

��

Choice of the type of voice: male, female ��

(if possible)

��

Vocalization of the advance functionalities (ex. HbbTV) ��

Table 4 – Summary table for TTS profile

6.2 RECEIVER INSTALLATION

This chapter contains the information which is presented in the DTG’s UK Digital TV Usability and Accessibility

Guidelines, including Text to Speech. It corresponds with the chapter 3 of the original document. It defines the

guidelines for the receiver installation: channel scanning, setting…

The guidelines for the first installation are:

1. A textual or vocal message shall inform the user on the need to connect the antenna to the receiver.

2. During the channel scan, the user shall be informed regularly about the number of found channels: display

and speech synthesis.

3. The user must be informed (display and speech synthesis) about the end of the channel scan and the

number of found channels.

4. The user shall enter his PIN code or parental code which shall be composed with 4 numbers. The code shall

be used for the channel locking. This code shall not be « 0000 ».

5. The user shall be able to set the receiver according to his needs for the installation phases:

1. Switch off the vocalisation (this one shall be available by default on the receiver),

2. Choose display settings: police font, police font size and contrast…

3. Choose the video and audio output,

4. Switch on the reading of audio description stream,

5. Switch on the reading of the deaf and hard of hearing subtitles



broadcast network

Page 31



6.3 ACCESS TO ELECTRONIC PROGRAM GUIDE

This chapter contains the information which is presented in the DTG’s UK Digital TV Usability and Accessibility

Guidelines, including Text to Speech. It corresponds with the chapter 4.6 of the original document. It defines the

guidelines for the access to electronic program guide:

1. The EPG shall be displayed to allow the user to compare and find events. It is recommended to display 5

channels in minimum by page for a period of two hours or two hours and thirty minutes.

2. The user shall be able to scroll through the EPG channels list and through programs list from time axe of

the zapping banner. The speed of the scrolling shall be determinate from user needs.

3. The color keys (if implemented on the remote control) should be used for EPG navigation.

4. The user should be able to create a callback or a record directly from EPG events.

5. EPG data given by providers shall be recorded and updated regularly by the receiver.

6. The user should be able to create favourite channels list for EPG displaying.

The follow picture describes the EPG homepage. The red arrows describe user movements on the page in order to

reach the event information.

Figure 8 - Example of accessible EPG homepage



broadcast network

Page 32



6.4 PARENTAL CONTROL

The descriptor parental_rating_descriptor contained in the EIT is used to define the event category according to the

CSA category. It is defined in the chapter 6.2.26 of the standard EN 300 468 V1.11.1, Digital Video Broadcasting

(DVB); Specification for Service Information (SI) in DVB systems.

Figure 9 - parental_rating_descriptor descriptor

- country_code: This code is composed of 3 characters and defines the country (ISO 3166, Codes for the

representation of names of countries). For example, the value of coutry_code for France is 0x66 0x72 0x61

and its mean « fra ».

- rating: Code defines the viewer minimum age

« rating » Description

0x00 No define

0x01 to 0x0F Minimum age = value (in decimal) + 3

For example: if the value of the descriptor rating is 0x0F the minimum age will be 18

in this case: 15 (0x0F in decimal) + 3

0x10 to 0xFF Used by broadcasters

Table 5 – Definition of the « rating » descriptor

The follow table contains the correspondence between the CSA descriptive code and the descriptor rating

contained in the parental_rating_descriptor:

Code Correspondence « rating » descriptor

I All age groups 0x00

II Not recommended for viewer under 10 years old 0x07

III Not recommended for viewer under 12 years old 0x09

IV Not recommended for viewer under 16 years old 0x0D

V Not recommended for viewer under 18 years old 0x0F

Table 6 – Events classification for viewersusers

The DTG document: UK Digital TV Usability and Accessibility Guidelines, including Text to Speech gives in the

chapter 4.10.1 the recommendations for the EPG.

1. The user shall be able to lock a channel in order to block the access to other users.

2. The user should be able to definitively delete a channel on the receiver (In this case, the channel scan will

be necessary to refind the channel).

3. The locked or deleted channels shall not be displayed in the EPG page.

4. The portal shall block the access to events which belong to the fifth category (that is not recommended for

viewers under 18 years old).



broadcast network

Page 33



7 RECOMMENDATIONS FOR CONTENT ACCESS

7.1 EIT SIGNALING IN THE FRENCH DTT NETWORK

EIT structure is detailed in the standard: ETSI EN 300 468 (V1.11.1 - chapter 5.2.4). The EIT tables are used to

transport the information for channels: name of the event, start time, duration, summary and parental control

code. The document written by the CSA: Services et profil de signalisation pour la diffusion de la télévision

numérique de terre métropolitaine et ultramarine - Version 3.2 juillet 2010 defines the format of the EIT table for

the french DTT network.

Figure 10 - Event_information_section descriptor

The table_id identifier is used to identify the EIT table type :

1. actual TS, present/following event information = table_id = "0x4E"

Table broadcasted in each network’s multiplex, inform about current and next events for the current

multiplex.

2. other TS, present/following event information = table_id = "0x4F"

Table broadcasted in each network’s multiplex, inform about current and next events for other network

multiplex.

3. actual TS, event schedule information = table_id = « 0x50 » to « 0x5F »

Table broadcasted in each network’s multiplex, inform the next events at large time scale for the current

multiplex.



broadcast network

Page 34



4. other TS, event schedule information = table_id = « 0x60 » to « 0x6F »

Table broadcasted in each network’s multiplex, inform the next events at large time scale for other

multiplexes.

Only the broadcasting of the EIT « present/following » table is mandatory in France. It’s specified in this decree:

“Arrêté signal du 24 décembre 2001, Article 2”.

The broadcasting of the EIT tables: EIT schedule Actual and EIT schedule Other is optional. However, they can be

broadcasted in each multiplex with information about the events for the next 7 days and an adapted data

repetition in order to limit the bit rate.

The standard ISO/IEC 62216 defines the list of descriptors (EN 300 468) that could be transported in EIT table and

that could be interpreted by the receiver.

Descriptor Header

stuffing_descriptor 0x42

linkage_descriptor 0x4A

short_event_descriptor 0x4D

extended_event_descriptor 0x4E

time_shifted_event_descriptor 0x4F

component_descriptor 0x50

CA_identifier_descriptor 0x53

content_descriptor 0x54

parental_rating_descriptor 0x55

telephone_descriptor 0x57

multilingual_component_descriptor 0x5E

private_data_specifier_descriptor 0x5F

short_smoothing_buffer_descriptor 0x61

data_broadcast_descriptor 0x64

PDC_descriptor 0x69

TVA_id_descriptor 0x75

content_identifier_descriptor 0x76

XAIT location descriptor 0x7D

extension descriptor 0x7F

stuffing_descriptor 0x42

Table 7 – Descriptors transported in EIT table

The follow descriptors are mandatory:

- component_descriptor

� Defines the format and contains textual elements.

- parental_rating_descriptor

� Defines the program category (CSA classification).

- short_event_descriptor

� Defines the format and contains some information about an event.

The CSA recommends that french broadcasters use the character type defines in the standard ISO/IEC 8859-9 if

accents are required in text (event name, summary….). In this case, it is necessary to precede the text with the

special character: 0x05. Moreover, transmitted texts in the different data fields shall not be written only with

capital letters but shall respect the french grammar: Capital letter for the beginning of sentence and proper nouns,

unless special cases, the rest of the sentence shall be written with lower case letter and if necessary accents and

other special characters. Some speech synthesis solutions use expressive forms in order to improve the realism of

the voice. Intonation is changed depending on punctuation to transcribe emotion of the word or the sentence.



broadcast network

Page 35



The EPG shall use the mandatory event information broadcasted in the SI tables and especially in the EIT tables.

Information is used by the receiver so as to be used for automatic characteristic selection of channels.

In that case, the following descriptors are transmitted (EN300468):

- parental_rating_descriptor

- component_descriptor that contains stream_content and component_type

The receiver shall interpret them to inform the user about event characteristics from EPG pages or zapping banner:

restriction age, availability of deaf or hard-of-hearing subtitles and audio-description.

7.2 SUBTITLING

7.2.1 SUBTITLES SIGNALING FOR THE FRENCH DTT BROADCAST NETWORK

The decree: “Arrêté « signal » du 24 décembre 2001” on digital terrestrial television which defines the

characteristics of DTT signals, specifies that subtitles (deaf and hard-of-hearing or original version subtitles) shall

broadcasted in accordance with the DVB Subtitling standard: ETSI EN 300 743: « Digital Video Broadcasting (DVB) ;

Subtitling systems ».

The standard ETSI EN 300 472 V1.3.1: Digital Video Broadcasting (DVB); Specification for conveying ITU-R System

B Teletext in DVB bitstreams is always in use in France for teletext subtitles and services. However, it will be

aborted in 2012.

The descriptor subtitling_descriptor (ETSI EN 300 468 V1.11.1) contained in the PMT table (ETSI EN 300 468

V1.11.1) gives information about the subtitle type as well as language.

Figure 11 - Subtitling_descriptor

- ISO_639_language_code: Field containing 24 bits that defines the subtitles language with 3 characters

code (ISO 639-2/B or ISO 639-2/T). Each character is coded on 8 bits. The french language for subtitles is

« fre », that is in hexadecimal: 0x66 0x72 0x61.

- subtitling_type: Field containing 8 bits that defines the subtitles type as well as display information. The

value is the same as the component_type when the stream_content value is 0x03.



broadcast network

Page 36



subtitling_type Description

0x10 DVB subtitles (normal) with no monitor aspect ratio criticality

0x11 DVB subtitles (normal) for display on 4:3 aspect ratio monitor

0x12 DVB subtitles (normal) for display on 16:9 aspect ratio monitor

0x13 DVB subtitles (normal) for display on 2.21: 1 aspect ratio monitor

0x14 DVB subtitles (normal) for display on a high definition monitor

0x20 DVB subtitles (for the hard of hearing) with no monitor aspect ratio criticality

0x21 DVB subtitles (for the hard of hearing) for display on 4:3 aspect ratio monitor

0x22 DVB subtitles (for the hard of hearing) for display on 16:9 aspect ratio monitor

0x23 DVB subtitles (for the hard of hearing) for display on 2.21:1 aspect ratio monitor

0x24 DVB subtitles (for the hard of hearing) for display on a high definition monitor

0x01 EBU Teletext subtitles

Table 8 - subtitling_type values

- composition_page_id: Field containing 16 bits that defines the PES identification header of the packets

that contain subtitle data: CLUT...

- ancillary_page_id: Optional field containing 16 bit that defines the PES identification header of the packets

that contain other subtitle data: CLUT definition table…

The fields stream_content and component_type (ETSI EN 300 468 V1.11.1) are contained in the descriptor

component_descriptor which is broadcasted in the EIT and SDT tables. They define the subtitles format and display

size (4:3, 16:9…).

stream_content Component_type Description

0x03 0x10 DVB subtitles (normal) with no monitor aspect ratio criticality

0x03 0x11 DVB subtitles (normal) for display on 4:3 aspect ratio monitor

0x03 0x12 DVB subtitles (normal) for display on 16:9 aspect ratio monitor

0x03 0x13 DVB subtitles (normal) for display on 2.21:1 aspect ratio monitor

0x03 0x14 DVB subtitles (normal) for display on a high definition monitor

0x03 0x20 DVB subtitles (for the hard of hearing) with no monitor aspect ratio

criticality

0x03 0x21 DVB subtitles (for the hard of hearing) for display on 4:3 aspect ratio

monitor

0x03 0x22 DVB subtitles (for the hard of hearing) for display on 16:9 aspect ratio

monitor

0x03 0x23 DVB subtitles (for the hard of hearing) for display on 2.21:1 aspect ratio

monitor

0x03 0x24 DVB subtitles (for the hard of hearing) for display on a high definition

monitor

0x03 0x01 EBU Teletext subtitles

Table 9 – Values of the stream_content and component_type fields

In the DVB subtitles structure, the base element that composes subtitles is called « segment » and corresponds to a

part of the subtitle data for one page. The segments are contained in PES packets: ISO/IEC 13818-1, the number of

segments is limited by the limit size of PES packet.

Currently, french broadcasters use the bitmap format for the DVB subtitles (ETSI EN 300 743). The text is converted

to graphic object and broadcasted as such format. This method allows them to choose and control presentation

options as police type and color. It ensures a better compatibility of subtitles with receivers that read the

DVB_Subtitling format (ETSI EN 300 743), because it is not necessary to store the police type library before.

The annexe B: ETSI EN 300 743 - Use of the DDS for HDTV gives recommendations for HD subtitles display.



broadcast network

Page 37



The descriptor display_definition_segment (ETSI EN 300 473 V1.3.1) contained in PES packet is used to define the

screen size associated for subtitles display. It gives the windows dimensions which is used to display subtitles for

HD

In France the DVB subtitles are broadcast on the DTT broadcast network with the follow values for the

subtitling_type:

For services with standard quality:

subtitling_type = 0x10, normal DVB subtitles (original version).

subtitling_type = 0x20, DVB subtitles provided for deaf and hard-of-hearing people.

For services with high definition quality:

subtitling_type = 0x14, normal DVB subtitles (original version).

subtitling_type = 0x24, DVB subtitles provided for deaf and hard-of-hearing people.

Figure 12 - Example of DVB subtitles with translucent banner

7.2.2 ACCESSIBILITY FOR THE SUBTITLING

The subtitling is an audio-visual technique that consists in displaying text over the video. There are two type types

of subtitles for television:

- Subtitles in french or in another foreign language

It consists on displaying synchronous with the dialogue a french translation if the audio is in french or any

other original language of a program,

- Subtitles for the deaf and hard of hearing people

This type of subtitles is achieved in the original language of the program. It is intended to deaf and hard-of-

hearing people and required a good readability.

In this context, the CSA defines a list of recommendations, for the broadcasters, on the subtitles for the deaf and

hard of hearing people:



broadcast network

Page 38



- The position of the subtitles on the screen shall be as close as possible to the sound source (character who

speaks…).

- The text of the subtitles shall be displayed with a black or translucent banner.

- Subtitles shall be displayed in accordance with the follow color codes:

• White when a visible (even partially) character is speaking

• Yellow when a no visible character is speaking

• Red for the noise indications

• Magenta for the musical indications and lyrics

• Cyan In the case of off-camera voice and thoughts of the narrator

• Green for the indications and foreign language transcription

• …

The decree: Arrêté terminal du 27 décembre 2001 defines that "receivers referred to the article 1 shall select and

display subtitles which are present in the received signal in accordance with ISO / IEC 62216, including those

destined for the hearing impaired". The functional implementation of subtitles shall follow the recommendations of

the ISO / IEC 62216 (Chapter 10). In the case where the "deaf or hard-of-hearing" subtitles are enabled (selection of

the subtitling_type = 0x20 for SD program or 0x24 for HD program), the receiver shall find and display the subtitles

(if they are available) for all viewed program. In this case, the user shall not have to enable this feature when he

selects a new program. The order of preference for the subtitles display when the feature is activated by the viewer

is the following in the case of an accessible receiver:

1. Subtitles for the deaf or hard-of-hearing people

2. Subtitles in french

Anymore, the activation or the deactivation of the subtitle display shall be easy. A special button shall be

implemented on the remote control and of course be accessible in the portal.

Currently, the “deaf or hard-of-hearing“ DVB subtitles (ETS 300 743) are generally displayed in a dark or black

banner. A modification of the subtitling display parameters (color, size and position) is necessary on the receiver in

order to improve the readability and to adapt the display in function of the viewer’s needs.

BACKGROUND BANNER CHANGE

The subtitling standard ETS 300 743 defines several means of transmitting the subtitles background banner. Even if

the standard does not define, manufacturers should implement a method in order to modify the CLUT table which

is used for the display color definition. It should be possible to define new values so as to create a black banner or

to delete it.

The broadcasters can decide to use the default CLUT table defined in the DVB standard or broadcast the desired

table.



broadcast network

Page 39



CLUT_definition_segment(){

sync_byte = 0F

segment_type = 0x12 (CLUT definition segment)

page_id = 2

segment_length = 98 Bytes

CLUT_id = 1

CLUT_version_number = 5

while (processed_length < segment_length)

CLUT_entry_id = 0

2-bit/entry_CLUT_flag = 0



full_range_flag = 1

Y = 0 Cr = 0 Cb = 0 T = 0

CLUT_entry_id = 1




full_range_flag = 1

…

}

CLUT is a mechanism that is used to reduce broadcasted information amount for each subtitle pixel. It allows to

transform broadcasted information in information used for color definition (RGB, YUV…). It is based on a

correspondence table that determines the colorimetric values from the transmitted data.

Figure 14 – CLUT mechanism

In the two previous cases, according to the used pixel depth, the values of the chrominance, the luminance and the

transparency (Y, Cr, Cb and T or R, G, B according to the used model) can be modified to obtain black or invisible

subtitle banner. To change these values, it is necessary to substitute the values contained in the CLUT table by

others to define the wanted display.

The receiver should recover the values contained in the broadcasted CLUT tables in order to substitute them by

new values according to viewer’s need for the colors and the contrasts. It is necessary to implement a mechanism

that allows analysing transmitted elements in order to determine which belong to the background banner. The

receiver will be able to change CLUT values: chrominance, luminance and transparency

CLUT table

00 -> 000 (RGB)

11 -> 111 (RGB)

Broadcasted

image 2 bits / pixel

00

00 00

11

Displayed

image

Figure 13 - Descriptor CLUT



broadcast network

Page 40



SUBTITLING SIZE CHANGE

Each pixel which constitutes the picture is transported by the signal as bits stream that defines display. The receiver

manufacturer should offer a mean to increase the subtitle size before send it to OSD. Scalability algorithms are

available and allow to change picture dimensions. Anymore, the use of spatial anti-aliasing methods should smooth

the forms shapes in order to limit edges distortion.

region_composition_segment()

sync_byte = 0F

segment_type = 0x11

page_id = 2

segment_length = 28

region_id = 0

region_version_number = 13

region_fill_flag = 1

region_width = 720

region_height = 38

region_level_of_compatibility = 2 (…)

while (processed_length < segment_length)

object_id = 31640

object_type = 0

object_provider_flag = 0

object_horizontal_position = 78

object_vertical_position = 0

…

}

A special attention should be brought to transmitted values that concern area dimensions and object position. In

the case of the increasing bitmap pictures for subtitles, it should be necessary to change these values in order to

obtain a good display.

SUBTITLING COLOR CHANGE

Manufacturer should implement a solution that allows to change subtitles color. Modification of the values

contained in the CLUT tables in the same way as background banner should be necessary.

Remark: The previous propositions are not defined in the DVB subtitling standard and in ISO/IEC 62216 standard,

they are provided to give indications for manufacturers.

7.3 AUDIO DESCRIPTION

7.3.1 AUDIO DESCRIPTION SIGNALING FOR THE FRENCH DTT BROADCAST NETWORK

Currently, audio description is broadcasted in France according to the « broadcaster-mix » mode. With this

technique, the description track and the main audio track are mixed together into a single stream. In this case, the

audio component is coded as a classical audio component, the format used in France are : MPEG-1 Layer II, AC3 or

E_AC3.

Audio description component is notified in the PMT and EIT tables that are associated with the event.

Figure 15 - Descripteur region_composition_segment



broadcast network

Page 41



PMT table signalling

Audio description track is signalled in the event’s PMT with the follow descriptors:

- The descriptor ISO_639_language_descriptor with a field audio_type = 0x00 means the stream

contains a track with main audio component mixed with audio description component. In this case,

the language of the component is given by the descriptor ISO_639_language_code = « qad »,

- The descriptor supplementary_audio_descriptor with a field mix_type =1. The language of the

component is defined by the descriptor ISO_639_language_code= « fre ».

EIT table signalling

The fields stream_content and component_type are transmitted with EIT tables and they inform about the audio

description component format:

Stream_content Component_type Description

0x02

0x47 Audio description coded with MPEG-1

Layer II mono or stereo.

0x04 0b01010xxx Audio description coded with AC3

(Dolby Digital)

0x04 0b11010xxx Audio description coded with E_AC3

(Dolby Digital+)

Table 10 - Stream_content and Component_type descriptors (broadcaster-mix)

Remark: The fields stream_content and component_type allows the differentiation of audio formats: AC3 or E_AC3.

Otherwise, the values of the last 3 bits of the descriptor component_type in the case of AC3 and E_AC3 audio

formats are used to inform about type, format and use of component as is defined the follow table extracted from

the standard EN 300468:



broadcast network

Page 42



Table 11 - component_type definition

In the future, some broadcaster could use in France the « receiver-mix » format for the audio description, especially

for HD format with A_C3 (Dolby Digital) or E_AC3 (Dolby Digital+).

7.3.2 ACCESSIBILITY FOR THE AUDIO DESCRIPTION

Receiver shall be able to:

• Receive audio description for the HD and SD programs,

• Access to the audio description regardless of the audio mode: broadcaster-mix or receiver-mix and

regardless of the signalling,

• Have a mean to access directly to the audio description track with the button « AD ». The descriptors

ISO_639_language_descriptor and supplementary_audio_descriptor used in the french network shall

be interpreted.

The implementation of the audio description feature for DTT receiver shall be compliant with the standard ISO/IEC

62216 (Chapter 7.4). The audio description track shall be read in priority when the viewer chose to use the feature.

Manufacturers should work on the implementation of the « receiver-mix » mode on the receiver. If this one is not

currently in use in France, it stays the better solution for the visual impaired people because it allows viewer to

change separately the sound levels.



broadcast network

Page 43



In this case, the receiver will be able to read two sound tracks at the same time in order to create a single output

stream. Receiver should be able to allow viewer to change the sound level for each track.

7.4 AUDIO FILTERING

Many solutions that allow the audio filtering for television soundtrack are available. These solutions make the

dialogue more intelligible. Receiver manufacturers should implement such solution so as to improve the audio

comfort for viewers. The annexe E of the standard ETSI TS 101 154 V1.9.1 gives informations to implement the

« clean audio » process, but this solution is based on the descriptor AD_descriptor() which is not yet used in France

on the DTT network.

The works of the Salford University (Manchester, UK) which is member of the UK Clean Audio Forum give elements

to improve understanding of dialogues in television programs.

7.5 ADVANCED FEATURES

Accessibility should be also brought to advances receiver features:

- Digital recording

The integration of a hard disk in the receiver allows viewers to access to recording and time shifting

functionalities. Implementation of these accessible features shall take into account the users specific

needs. The main recommendations are:

1. Access menus shall be vocalized and implemented respecting the recommendations for the user

interface.

2. Vocalization shall return the most important elements to manage record functionalities and time

shifting functionalities :

– Name of the function that is in use,

– Time offset from the direct,

– Position in the record,

– Speed information for the functions « Fast rewind » et « Fast forward »,

– …

3. Records on the hard disk shall contain the subtitles data and the audio description track.

Anymore, all the metadata transmitted with the program shall also be saved.

4. The mechanism that locks programs shall also be implemented for the records. Manufacturer

shall hide from the list the programs that are not recommended for viewer under 18 years old or

that have been locked by the user.

5. The follow scheme presents actions users can achieve and elements that should be returned

when the « pause » functionality is used.



broadcast network

Page 44



1. PLAY

PAUSE 2. RETURN/STOP/BACK

3. Other buttons

- Media center:

The Media center allows playing and organizing various types of medias that are available from various

data storage devices. Main recommendations are:

1. Access menus shall be vocalized and implemented respecting the recommendations for the user

interface.

2. Vocalization shall return the most important elements to manage record functionalities:

– Name of the function that is in use,

– Time offset from the direct,

– Position in the record,

– Speed information for the functions «Fast rewind » and « Fast forward »,

– …

- HbbTV

Interactivity according to the HbbTV standard (ETSI TS 102 796) is currently being deployed on DTT and

will in future be increasingly used by French broadcaster to provide additional services. The accessibility of

these services requires to adapt the display to the needs of visually impaired and a strategy to implement

the vocalization for the visual disabled people.

8 METHODOLOGY FOR ASSESSING THE ACCESSIBILITY OF A RECEIVER

The accessibility shall be validated throughout the implementation of the television receiver in order to control that

functionalities correspond to viewer needs. Writing and realization of tests plan are mandatory; these shall be

executed by people with disabilities.

The following questions allow to validate the viewers needs. They shall be used to throughout the project:

- Who will use the receiver?

- What are the specific viewer needs?

- What is the utilization context?

Figure 16 – Accessibility for the « PAUSE » function

– The system announces “pause” mode is active

– The system shows the time offset from the direct

– The system presents the user's possible actions, including how to

get back to direct


– The system asks viewer to confirm the action


– The system shows the time offset from the direct

– The system presents the user's possible actions, including

how to get back to direct



broadcast network

Page 45



- How it will be used?

- What is the user frequency of use?

- What is the level of knowledge required to use the television receiver?

- Is user interface adapted to people with disabilities?

The technical report IEC/TR 62678 ed1.0 gives a list of points that could be checked in order to validate the

equipment accessibility for people with disabilities (IEC/TR 62678 ed1.0: Table 4 – Checklist of accessibility and

usability considerations).

9 CONCLUSION

Today, no standard clearly defines the elements to be implemented in order to achieve an accessible and vocalize

DTT receiver. The only standards and standardization activities available that address the issues of accessibility are

either generic or cross-functional to technologies and services. They therefore do not permit manufacturers to

clearly define the technical and functional boundaries.

However, the conception shall follow as much as possible the existing recommendations which define accessibility

functionalities as vocalization for television receiver. The technical report IEC/TR 62678 ed1.0 and the two DTG list

of recommendations: UK Digital TV Usability and Accessibility Guidelines, including Text to Speech and

Implementation guidelines and recommendations for text-to-speech v1.4 give the list of the useable standard as

well as technical and functional recommendations in order to implement such a receiver.

The main recommendations are:

- Define in the specification sheet the necessary functionalities for helping the people who have the most

difficulty to watch television: deaf, hard-of-hearing, blind people and elderly…

- Appeal association for disabled people in order to identify the needs and validate the solution. This step

allow to ensure the receiver will respond user expectations,

- Implement user interface that is adapted for visual disabled people: contrast, color, sound signals…

- Implement a portal easy to use: terminology, organization of menus …

- Make the main features (access to subtitles and audio description ...) accessible by simply pressing a

button on the remote control which should have an accessible design,

- Integrate in the receiver a vocalization solution with an adapted implementation in order to return all the

needed information for visually impaired user,

- Rely on existing standards and recommendations from RNIB, INTECO, NCAM and DTG as well as European

and International standardization organizations,

- Ensure the receiver compatibility with the signaling used for DTT broadcasting in France. It shall be

necessary to achieve laboratory tests from audiovisual recordings of the broadcasted transport stream

multiplex.

The lack of accessibility standards in the area of audiovisual equipment and services for the general public shall be

promptly filled. Only the precise definition of functionalities and their implementation in standards validated by the

International and European organizations (ITU, ISO, IEC, EBU ...) will encourage manufacturers to develop solutions

and services usable by the largest number of users and which take into account their abilities and their needs.



broadcast network

Page 46



10 BIBLIOGRAPHY, STANDARDS AND REFERENCE DOCUMENTATIONS

LEGISLATION

1. Law n°86-1067 of the September 30, 1986 (Loi n°86-1067 du 30 septembre 1986)

Information available on the site www.legifrance.gouv.fr

2. Decree of the december 27, 2001 relating to the characteristics of the reception equipment for services

broadcasted by digital terrestrial television (Arrêté du 27 décembre 2001 relatif aux caractéristiques des

équipements de réception des services diffusés par voie hertzienne numérique terrestre )

Modified by the decree of the May 26, 2005

Information available on the site of the « Journal Officiel »

3. Decree of the December 24, 2001 relating to the digital terrestrial television and setting the characteristics of

the broadcasting signals (Arrêté du 24 décembre 2001 relatif à la télévision numérique hertzienne terrestre

fixant les caractéristiques des signaux émis )

Modified by:


- The decree of the august 25, 2010

Information available on the site of the « Journal Officiel »

4. Quality charter for the subtitling destined for the hard of hearing and deaf people (Charte de qualité pour le

sous-titrage à destination des personnes sourdes ou malentendantes)

Information available on the site www.csa.fr

5. Law n°2007-309 of the March 5, 2007 relating to the modernization of the audio-visual broadcast and the

television of the future (Loi n° 2007-309 du 5 mars 2007 relative à la modernisation de la diffusion

audiovisuelle et à la télévision du futur)

Information available on the site www.legifrance.gouv.fr

STANDARDS AND TECHNICAL REPORTS

1. Technical report « Services et profil de signalisation pour la diffusion de la télévision numérique de terre

métropolitaine et ultramarine - Version 3.2 juillet 2010 »

Document available on the CSA website: www.csa.fr

2. ISO/IEC 62216 (may 2009) Digital terrestrial television receivers for the DVB-T system

3. ISO/IEC 13818-2 Information technology - Generic coding of moving pictures and associated audio information:

Video



broadcast network

Page 47



4. ISO/IEC 14496-10 Information technology - Coding of audio-visual objects - Part 10: Advanced Video Coding

5. ISO/IEC 13818-3 Information technology - Generic coding of moving pictures and associated audio information

- Part 3: Audio

6. ISO/TR 22411:2008 Ergonomics data and guidelines for the application of ISO/IEC Guide 71 to products and

services to address the needs of older persons and persons with disabilities

7. ISO 9241-20:2008: Ergonomics of human-system interaction - Part 20: Accessibility guidelines for

information/communication technology (ICT) equipment and services

8. ISO/IEC TR 29138-1: Information technology - Accessibility considerations for people with disabilities — Part 1:

User needs summary

9. ISO/IEC 62731 Ed. 1.0 Text-to-Speech Functionality for Television - General requirements (In normalization

process)

10. IEC/TR 62678 ed1.0 Audio, video and multimedia systems and equipment activities and considerations related

to accessibility and usability - 2010-10-05

11. ES 201 381 Human Factors (HF); Telecommunications keypads and keyboards; Tactile identifiers

12. AcceDe PDF: http://www.pdf-accessible.com

13. European organization recommendations « European Blind Union »: http://www.euroblind.org/

14. Web Content Accessibility Guidelines (WCAG) 2.0: W3C

15. User Agent Accessibility Guidelines (UAAG) 1.0: W3C

16. ISO 7001:2007 Graphical symbols - Public information symbols

17. ISO/IEC 24786:2009 Information technology - User interfaces - Accessible user interface for accessibility

settings

18. ETSI EN 300 468 V1.11.1 Digital Video Broadcasting (DVB);Specification for Service Information (SI) in DVB

systems

19. ETSI EN 300 743 Digital Video Broadcasting (DVB) ; Subtitling systems

20. ISO/IEC Guide 71:2001 Guidelines for standards developers to address the needs of older persons and persons

with disabilities

21. ETSI EN 300 472 V1.3.1: Digital Video Broadcasting (DVB); Specification for conveying ITU-R System B Teletext

in DVB bitstreams

22. ISO 639-2/B Language code list

23. ISO 639-2/T Language code list

24. ISO 7001: Public Information Symbols.

25. ISO/IEC 13818-1 Information technology - Generic coding of moving pictures and associated audio information:

Systems.

26. VoiceXML 3.0 - W3C Working Draft 16 December 2010

27. HTML5: W3C



broadcast network

Page 48



RECOMMENDATIONS

1. UK Digital TV Usability and Accessibility Guidelines, including Text to Speech

Document available on the site www.dtg.org.uk

2. Implementation guidelines and recommendations for text-to-speech v1.4

Document available on the site www.dtg.org.uk

3. DIGITAL TERRESTRIAL TELEVISION (DTT) ACCESSIBILITY RECOMMENDATIONS - INTECO

Document available on the site www.inteco.es

4. Developer's Guide to Creating Talking Menus for Set-top Boxes and DVDs (NCAM - USA)

Document available on the site www.ncam.wgbh.org

5. EBU-Tech 3344 (Practical guidelines for distribution systems in accordance with EBU R 128)

Document available on the site http://tech.ebu.ch

ADDITIONAL INFORMATION

1. E-inclusion european project

Information available on the site http://ec.europa.eu/information_society/activities/einclusion/index_en.htm

2. TV-access

Information available on the site www.tvaccess.ie

3. RNIB

Information available on the site www.rnib.org.uk

4. Working group on the accessibility

Information available on the site www.tiresias.org

5. DTV4ALL

Information available on the site www.psp-dtv4all.org

6. e-Accessibility Policy Toolkit for Persons with Disabilities

Information available on the site www.e-accessibilitytoolkit.org/toolkit/technology_areas/television

7. « Color Contrast Analyser » software

Available on the following link: http://www.visionaustralia.org.au/info.aspx?page=961

8. Web Accessibility Initiative (WAI)

Information available on the site www.w3.org/WAI/users/Overview.html



broadcast network

Page 49



11 ANNEXE

This document presents only the technical functions that could be implemented in the context of television

receiver that receive broadcasted data from DTT. In this case, the receiver is only connected to an antenna for

receiving signal.

Hybrid solutions that associate broadcast and broadband broadcasting (OTT, HbbTV…) could allow to receive

additional accessibility contents: subtitles, audio description, but also to carry elements to portal in order to

increase for example the number of setting options (new police font, new colors…). HTML5 language could be used

to implement the vocalization.

For the distribution of audiovisual contents associated with accessibility (subtitles and audio description), existing

solutions allow the synchronizing of the stream of broadcast television with the data from the internet.

The use of tablets and other multimedia equipment such as smartphones can also bring new services to the user to

improve access to television. Touchscreens could become ergonomic remote or alternative interfaces for the

portal; the smartphones can also receive the audio description stream and then return it to a user.

Figure 17 - HbbTV architecture

Date post:	05-Jan-2017
Category:	Documents
Upload:	vanhanh
View:	223 times
Download:	3 times

Rapport 3 Talking TV IRD Functional and technical specifications

Documents