IEC 62731:2018

IEC 62731 ®
Edition 2.0 2018-01
INTERNATIONAL
STANDARD
Text-to-speech for television – General requirements
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 21 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - webstore.iec.ch/advsearchform IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 67 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC 62731 ®
Edition 2.0 2018-01
INTERNATIONAL
STANDARD
Text-to-speech for television – General requirements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.25; 33.160.99 ISBN 978-2-8322-5125-6

– 2 – IEC 62731:2018 © IEC 2018
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions . 5
3.2 Abbreviated terms . 6
4 Guiding principles and conventions . 7
5 User requirements of visually impaired people . 7
5.1 Users' needs . 7
5.2 Navigating channels . 8
5.3 Navigating TV inputs . 8
5.4 Additional data services . 8
5.5 Operating the TV . 8
5.6 TV use . 8
6 Functional requirements . 9
6.1 Functionality for TV, TTS device combination . 9
6.2 Functionality: TTS device/engine . 10
6.3 Functionality: TV . 10
6.4 Setting up: TV, TTS device combination . 11
7 TV events and TTS data . 11
7.1 TV context and events . 11
7.2 TTS data per event . 12
7.2.1 Details . 12
7.2.2 Channel change . 12
7.2.3 Additional information . 13
7.2.4 Navigation and selection . 13
7.2.5 Context switch . 14
7.2.6 Pop-up message . 16
8 TTS profiles . 16
8.1 Basic profile . 16
8.2 Main profile . 16
8.3 Enhanced profile . 17
8.4 Summary . 18
Bibliography . 19

Figure 1 – TV – TTS device system diagram . 9
Figure 2 – Context event state diagram . 12

Table 1 – Overview of profiles . 18

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TEXT-TO-SPEECH FOR TELEVISION –
GENERAL REQUIREMENTS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC
Publication(s)"). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62731 has been prepared by IEC technical committee 100: Audio,
video and multimedia systems and equipment.
This second edition cancels and replaces the first edition published in 2013. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) in 6.2, the levels of announcement quality were revised as well as considerations for ways
in which device users can provide service providers with feedback on incorrectly
announced terms.
b) in 6.3, the following TV functionality was added: the TV can receive updated words,
associated conversions and updated conversion rules for the TTS engine via a network
connection.
– 4 – IEC 62731:2018 © IEC 2018
The text of this standard is based on the following documents:
FDIS Report on voting
100/2989/FDIS 100/3013/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

TEXT-TO-SPEECH FOR TELEVISION –
GENERAL REQUIREMENTS
1 Scope
This International Standard specifies the text-to-speech functionality for a (broadcast) receiver
with a text-to-speech system. Such a system may be one device, i.e. a receiver with an
integrated text-to-speech generator, or may be two devices, i.e. a receiver interfacing with an
external text-to-speech device. This document applies only to completely functional stationary
(or semi-stationary) digital TV receivers such as set top boxes, integrated digital TVs,
recorders and other products whose primary function is to receive TV content. Where this
document refers to TV, this will be shorthand for all such receivers.
This document does not apply to products that are capable of receiving TV as a secondary
function (e.g. PCs or game consoles with digital television receivers). It also does not apply to
sub-assemblies (e.g. PC tuner cards).
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
context
one specific function of a TV
EXAMPLE: Watching TV, EPG.
3.1.2
DTV broadcast event classification
general category of programme/event content, or its classification
EXAMPLES: Movie (drama), news/current affairs, talk show, sports (football).
3.1.3
EPG filter
filter that organises or re
...