INTERNATIONAL ISO/IEC STANDARD 14496-17 First edition 2006-04-01 Information technology Coding of audio-visual objects - Part 17: Streaming text format Technologiesde I'information-Codagedes objetsaudiovisuels- Partie 17:Format detexteen flux Reference number ISO/IEC 14496-17:2006(E) IEC tso @ISO/IEC2006 ISO/IEC14496-17:2006(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation the unlikely event that a problem relating to it is found, please infom the Central Secretariat at the address given below. ISO/IEC2006 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 ISO at the address below or IsO's member body in the country of the requester. ISO copyright office Case postale 56.CH-1211Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland ii @ ISO/IEC 2006 All rights reserved ISO/IEC14496-17:2006(E) Contents Page Foreword. Introduction vi 1 Scope 2 Normativereferences 3 Terms and definitions... 4 Text stream format.. 5 Text access units.... 5.1 Timing and decoding of text access units . 5.2 Format of textaccess units... 5.3 TextConfig.... 5.4 Semantics. 6 Usage of a text stream within anMPEG-4 system context. 6.1 Signaling of a text stream.. 6.2 Usage in the scene description.. Text data format for 3GPP text streams.. 7.1 7.2 Carriageoftextsamplesandsampledescriptions in3GPPtextaccessunits 7.3 Transport of3GPPtextaccess units inTTUs... 7.4 TTU Syntax and Semantics...... 7.5 Positioningof3GPPtextstreams. 13 7.6 Formatspecificdecoderconfigurationfor3GPPtextstreams... 14 7.7 Hypothetical Text Decoder for 3GPP text stream decoding.... 7 7.8 Profile and Levelparameters for3GPPtext streams.. 18 Annex A (normative)Font Referencing... 19 AnnexB (informative)Transport ofTextStreams... @ ISO/IEC 2006 - All rights reserved ii ISO/IEC14496-17:2006(E) Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)form the specialized system for worldwide standardization. National bodies that are members of established by the respective organization to deal with particular fields of technical activity. IsO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with IsO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. ISO/IEC 14496-17 was prepared by Joint Technical Committee ISO/IEC JTC1,Information technology, SubcommitteeSC29,Codingofaudio,picture,multimediaandhypermedia information. ISO/lEC 14496 consists of the following parts, under the general title Information technolog