ISO/IEC 14496-18:2004/Amd 1:2014
(Amendment)Information technology — Coding of audio-visual objects — Part 18: Font compression and streaming — Amendment 1: Updated semantics of decoderSpecificInfo and font data description for ISOBMFF
Information technology — Coding of audio-visual objects — Part 18: Font compression and streaming — Amendment 1: Updated semantics of decoderSpecificInfo and font data description for ISOBMFF
Technologies de l'information — Codage des objets audiovisuels — Partie 18: Compression et transmission de polices de caractères — Amendement 1: Sémantique de decoderSpecificInfo mise à jour et description des données de police pour ISOBMFF
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INTERNATIONAL ISO/IEC
STANDARD 14496-18
First edition
2004-07-01
AMENDMENT 1
2014-10-01
Information technology — Coding of
audio-visual objects —
Part 18:
Font compression and streaming
AMENDMENT 1: Updated semantics
of decoderSpecificInfo and font data
description for ISOBMFF
Technologies de l’information — Codage des objets audiovisuels —
Partie 18: Compression et transmission de polices de caractères
AMENDEMENT 1: Sémantique de decoderSpecificInfo mise à jour et
description des données de police pour ISOBMFF
Reference number
ISO/IEC 14496-18:2004/Amd.1:2014(E)
©
ISO/IEC 2014
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ISO/IEC 14496-18:2004/Amd.1:2014(E)
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ISO/IEC 14496-18:2004/Amd.1:2014(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 ISO or IEC participate in the development of International Standards through technical
committees 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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for
the different types of document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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.
Details of any patent rights identified during the development of the document will be in the Introduction
and/or on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword — Supplementary information.
The committee responsible for this document is ISO/IEC JTC 1, Information technology, Subcommittee
SC 29, Coding of audio, picture, multimedia and hypermedia information.
This amendment modifies the description and format of some existing fields of the decoderSpecificInfo
and also provides a definition of font data box for ISO Base Media File Format.
© ISO/IEC 2014 – All rights reserved iii
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ISO/IEC 14496-18:2004/Amd.1:2014(E)
Information technology — Coding of audio-visual
objects —
Part 18:
Font compression and streaming
AMENDMENT 1: Updated semantics of decoderSpecificInfo and
font data description for ISOBMFF
In clause 2 “Normative References”, add the following text in the end of the clause:
ISO/IEC 14496-22, Information technology — Coding of audio-visual objects — Open Font Format
ISO/IEC 14496-28, Information technology — Coding of audio-visual objects — Composite Font
Representation
In clause 3 “Font Data Format”, replace the second paragraph with the following text:
MPEG-4 adopts ISO Open Font Format defined in ISO/IEC 14496-22 as its font data format for the purposes
1)
of uniform font data transmission and predictable text rendering. Originally based on OpenType® , it
has emerged as the font solution for high-quality text processing, multimedia applications and cross
platform Internet document portability. OFF is a full-featured font format that enables the highest
quality of text rendering on low-resolution displays, advanced typographic features and international
2)
character support. It is fully compatible with the existing and widely adopted TrueType™ fonts.
In subclause 5.2.3 “Semantics”, replace “Table 10” with the following:
Table 10 — fontFormat values for EnhancedAccessUnit
fontFormat
Access unit content
0x00 Forbidden
0x01 ISO OFF / OpenType font with TrueType outlines
(uncompressed)
0x02 ISO OFF / OpenType font with TrueType outlines
compressed using the compression mechanism described in
subclause 4.2
0x03 ISO OFF / OpenType font with CFF outlines
0x04 Composite Font Representation (as defined by
ISO/IEC 14496-28)
0x05 – 0x3F ISO reserved
0x40 – 0x7F User private
In subclause 5.2.3 “Semantics”, add the following text in the end of the subclause:
The ‘fontName’ field in the enhanced access unit header defines the font name that, together with the
supplied font data, shall be used for font matching and shall override the font name specified by the
underlying font data. This allows a content author to have a complete control over the font chosen for
1) OpenType is a registered trademark of Microsoft Corporation.
2) TrueType is a trademark of Apple Computer Incorporated.
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ISO/IEC 14496-18:2004/Amd.1:2014(E)
content presentation and to avoid any potential conflicts with similarly named fonts that may be present
in a given presentation environment.
The enhanced access units of a font stream can be used to deliver multiple fonts at the same time, and
each of those fonts can be delivered either as a single complete font or subdivided into smaller subsets.
In case when font subsets are used, each font subset shall have its own unique ‘fontSubsetID’. A font
subset may either contain a complete collection of glyphs that are needed to display a certain text
fragment and, therefore, be used for a period of time and then be replaced with another subset, or it may
be used to deliver only missing glyphs that were not included in the previously sent subset(s) of the same
font. In the latter case, the initial font subset shall have ‘storeFont’ flag set to indicate that a terminal
shall temporarily store the initial font subset, and all subsequent font subsets shall have ‘storeFont’
and ‘fontSubsetExtensionFlag’ set to indicate that a newly delivered font subset is an extension of the
previously delivered font subset.
A terminal should either combine multiple font subset extensions into a single font file or should treat
them as a virtual font collection, with each fon
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