CAN CSA-ISO IEC 14496-18-2005 Information technology - Coding of audio-visual objects - Part 18 Font compression and streaming (Technical Corrigendum 1 August 2007).pdf

1、 Reference numberISO/IEC 14496-18:2004(E)ISO/IEC 2004Information technology Coding of audio-visual objects Part 18: Font compression and streaming Technologies de linformation Codage des objets audiovisuels Partie 18: Compression et transmission de polices de caractres National Standard of CanadaCAN

2、/CSA-ISO/IEC 14496-18:05(ISO/IEC 14496-18:2004)International Standard ISO/IEC 14496-18:2004 (first edition, 2004-07-01) has been adopted withoutmodification (IDT) as CSA Standard CAN/CSA-ISO/IEC 14496-18:05, which has been approved as a NationalStandard of Canada by the Standards Council of Canada.I

3、SBN 1-55397-954-0 October 2005The Canadian Standards Association (CSA), under whose auspices this National Standard has been produced, was chartered in 1919 and accredited by the Standards Council of Canada to the National Standards system in 1973. It is a not-for-profit, nonstatutory, voluntary mem

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10、al and international needs.For further information on CSA services, write toCanadian Standards Association5060 Spectrum Way, Suite 100Mississauga, Ontario, L4W 5N6CanadaThe Standards Council of Canada is the coordinating body of the National Standards system, a federation of independent, autonomous

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16、efore, users are cautioned to obtain the latest edition from the organization preparing the standard.The responsibility for approving National Standards of Canada rests with theStandards Council of Canada270 Albert Street, Suite 200Ottawa, Ontario, K1P 6N7CanadaAlthough the intended primary applicat

17、ion of this Standard is stated in its Scope, it is importantto note that it remains the responsibility of the users to judge its suitability for their particular purpose.Registered trade-mark of Canadian Standards AssociationCette norme est offerte en anglais seulement pour le moment. La CSA publier

18、a la version enfranais ds quelle sera produite par lorganisme rdacteur.ICS 35.040 Ref. No. ISO/IEC 14496-18:2004/Cor.1:2007(E) ISO/IEC 2007 All rights reserved INTERNATIONAL STANDARD ISO/IEC 14496-18:2004 TECHNICAL CORRIGENDUM 1 Published 2007-02-01 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORG

19、ANISATION INTERNATIONALE DE NORMALISATIONINTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION LECTROTECHNIQUE INTERNATIONALEInformation technology Coding of audio-visual objects Part 18: Font compression and streaming TECHNICAL CORRIGENDUM 1 Technologies de linformation Codage des objets audiovisuel

20、s Partie 18: Compression et transmission de polices de caractres RECTIFICATIF TECHNIQUE 1 Technical Corrigendum 1 to ISO/IEC 14496-18:2004 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia informat

21、ion. International Organization for Standardization (ISO), 2007. All rights reserved. International Electrotechnical Commission (IEC), 2007. All rights reserved. NOT FOR RESALE.Technical Corrigendum 1:2007 toNational Standard of CanadaCAN/CSA-ISO/IEC 14496-18:05Technical Corrigendum 1:2007 to Intern

22、ational Standard ISO/IEC 14496-18:2004 has been adopted withoutmodification (IDT) as Technical Corrigendum 1:2007 to CAN/CSA-ISO/IEC 14496-18:05. This TechnicalCorrigendum was reviewed by the CSA Technical Committee on Information Technology (TCIT) under thejurisdiction of the Strategic Steering Com

23、mittee on Information Technology and deemed acceptable for use inCanada.August 2007ISO/IEC 14496-18:2004/Cor.1:2007(E) 2 ISO/IEC 2007 All rights reservedIn subclause 4.2.4.7, replace the first 20 lines of Table 9 with the following: 0 2 0 8 N/A 0 N/A + 1 0 - 2 256 + 3 256 - 4 512 + 5 512 - 6 768 + 7

24、 768 - 8 1024 + 9 1024 - 10 2 8 0 0 N/A + N/A 11 0 - 12 256 + 13 256 - 14 512 + 15 512 - 16 768 + 17 768 - 18 1024 + 19 1024 - In subclause 5.2.1, replace the text of the first paragraph: A font data access unit conveys data for one single font, or a subset thereof. Two access unit formats are speci

25、fied, discriminated by the DecoderSpecificInfo for the font data stream (see subclause 5.4). Only one of these access unit formats can be selected for a given font data stream. with the following text: A font data access unit conveys data for one single font, or a subset thereof. Fonts may support a

26、 wide variety of different languages and may have a large number of glyphs. While there are some fonts that support, for example, full Latin character set, there are other fonts that support only English alphabet, which can be considered a subset of Latin characters. When a font is used for text ren

27、dering, only a limited number of glyphs can be utilized, and the transmission of the whole font may not be necessary. In order to reduce the amount of data sent, and to improve the efficiency of the font data streams, fonts can be reduced in size (subsetted) by keeping only those glyphs that are uti

28、lized in a particular text fragment, and the additional required general font information. Therefore, the font subsets are complete, self-sufficient and fully functional fonts containing a limited number of glyphs. A font subset shall be conformant to the fontFormat specified in the header of the ac

29、cess unit. When the value of fontFormat is 0x01, 0x02 or 0x03, the content of fontData shall be conformant to OpenType specification, containing, at least, all required tables specified by the OpenType specification. Two access unit formats are specified, discriminated by the DecoderSpecificInfo for

30、 the font data stream (see subclause 5.4). Only one of these access unit formats can be selected for a given font data stream. Technical Corrigendum 1:2007 toCAN/CSA-ISO/IEC 14496-18:05 ISO/IEC 14496-18:2004/Cor.1:2007(E) ISO/IEC 2007 All rights reserved 3In subclause 5.2.1, replace the text of the

31、second and third paragraphs: The basic access unit format permits to convey font data without any header information. The DecoderSpecificInfo provides the identification of the font and, possibly, the subset thereof that is conveyed. The content of subsequent basic access units in such a font data s

32、tream shall replace the font or font subset data of previous basic access units. The enhanced access unit format provides a self-contained format where an access unit header contains all necessary information about the font data conveyed in this access unit. with the following text: The basic access

33、 unit format permits to convey font data without any header information. The DecoderSpecificInfo provides the identification of the font and, possibly, the subset thereof that is conveyed. The content of subsequent basic access units in such a font data stream shall replace the font or font subset d

34、ata of previous basic access units with the same fontName and fontSubsetID (if applicable). The enhanced access unit format provides a self-contained format where an access unit header contains all necessary information about the font data conveyed in this access unit. The content of subsequent enha

35、nced access unit replaces or complements the font or font subset of the previous basic or enhanced access unit with the same fontName and fontSubsetID, based on the fontSubsetExtensionFlag, as described in subclause 5.2.3.This functionality allows incremental updates of font data and efficient font

36、streaming implementations. In subclause 5.2.3, replace the current description of: fontSubsetExtensionFlag if set to one indicates that the font data in this access unit is an extension of the previously sent font subset with the same fontName and fontSubsetID. Otherwise the font subset replaces any

37、 previous font subset with the same fontName and fontSubsetID. with the following text: fontSubsetExtensionFlag if set, indicates that the font data in this access unit is an extension of the previously sent font subset with the same fontName and fontSubsetID. The data presented in the current acces

38、s unit extends the previously sent font subset data, i.e. a new font subset provides additional glyphs that complement previously sent font subset with the same font name and font subset ID. These two subsets can either be merged in the decoder, or can be used concurrently as two different font subs

39、ets of the same original font. If fontSubsetExtensionFlag is not set, the font subset replaces any previous font subset with the same fontName and fontSubsetID. In Annex A “Patent Statements“, replace the table containing company names with the following: Company Apple Computer Microsoft Corporation

40、 Monotype Imaging Inc. Technical Corrigendum 1:2007 toCAN/CSA-ISO/IEC 14496-18:05CAN/CSA-ISO/IEC 14496-18:05Information technology Coding of audio-visualobjects Part 18: Font compression and streamingOctober 2005 Canadian Standards Association CSA/1CAN/CSA-ISO/IEC 14496-18:05Information technology C

41、oding of audio-visual objects Part 18: Font compression and streamingCSA PrefaceStandards development within the Information Technology sector is harmonized with international standards development. Through the CSA Technical Committee on Information Technology (TCIT), Canadians serve as the Canadian

42、 Advisory Committee (CAC) on ISO/IEC Joint Technical Committee 1 on Information Technology (ISO/IEC JTC1) for the Standards Council of Canada (SCC), the ISO member body for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of the International Telecommunication Unio

43、n (ITU), Canada participates in the International Telegraph and Telephone Consultative Committee (ITU-T).At the time of publication, ISO/IEC 14496-18:2004 is available from ISO and IEC in English only. CSA will publish the French version when it becomes available from ISO and IEC.This International

44、Standard was reviewed by the CSA TCIT under the jurisdiction of the Strategic Steering Committee on Information Technology and deemed acceptable for use in Canada. (A committee membership list is available on request from the CSA Project Manager.) From time to time, ISO/IEC may publish addenda, corr

45、igenda, etc. The CSA TCIT will review these documents for approval and publication. For a listing, refer to the CSA Information Products catalogue or CSA Info Update or contact a CSA Sales representative. This Standard has been formally approved, without modification, by the Technical Committee and

46、has been approved as a National Standard of Canada by the Standards Council of Canada.October 2005 Canadian Standards Association 2005All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permission ofthe publisher. ISO/IEC material is reprinted

47、with permission. Where the words “this International Standard” appear in the text, they should be interpreted as “this National Standard of Canada”.Inquiries regarding this National Standard of Canada should be addressed toCanadian Standards Association5060 Spectrum Way, Suite 100, Mississauga, Onta

48、rio, Canada L4W 5N61-800-463-6727 416-747-4044www.csa.caReference numberISO/IEC 14496-18:2004(E)ISO/IEC 2004INTERNATIONAL STANDARD ISO/IEC14496-18First edition2004-07-01Information technology Coding of audio-visual objects Part 18: Font compression and streaming Technologies de linformation Codage d

49、es objets audiovisuels Partie 18: Compression et transmission de polices de caractres ISO/IEC 14496-18:2004(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to