ISO/IEC 14496-4:2004/Amd 24:2008

INTERNATIONAL ISO/IEC
STANDARD 14496-4
Second edition
2004-12-15
AMENDMENT 24
2008-06-01

Information technology — Coding of
audio-visual objects —
Part 4:
Conformance testing
AMENDMENT 24: File format conformance
Technologies de l'information — Codage des objets audiovisuels —
Partie 4: Essai de conformité
AMENDEMENT 24: Conformité de format de fichier




Reference number
ISO/IEC 14496-4:2004/Amd.24:2008(E)
©
ISO/IEC 2008

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ISO/IEC 14496-4:2004/Amd.24:2008(E)
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ISO/IEC 14496-4:2004/Amd.24:2008(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.
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.
Amendment 24 to ISO/IEC 14496-4:2004 was prepared by Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia
information.

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ISO/IEC 14496-4:2004/Amd.24:2008(E)

Information technology — Coding of audio-visual objects —
Part 4:
Conformance testing
AMENDMENT 24: File format conformance
Rename the title of 4.7:
4.7 MP4 File Format
to:
4.7 File Format

In 4.7 insert the following subclause: renumbering existing Subclauses 4.7.1 and 4.7.2 as 4.7.2 and 4.7.3
respectively:
4.7.1 Introduction
This subclause describes the conformance suite for the file format standards in MPEG-4. Since these
standards share a lot of technology, their conformance program is being handled together. These standards
are:
1) ISO/IEC 14496-12 (technically identical to ISO/IEC 15444-12): ISO base media file format
2) ISO/IEC 14496-14: MP4 file format
3) ISO/IEC 14496-15: Advanced Video Coding (AVC) file format (Storage of AVC in ISO files)
The purpose of the conformance suite is to cover the set of valid features that may be exercised in the file
format. Media conformance is not covered, though of course in order to exercise the file format features,
media has to be stored.
In order to assure coverage of features, the associated spreadsheet is used to list the features in groups, and
to document which files exercise each feature. Features not currently covered by any file are marked with the
sign “---“.

After 4.7.3: Reading, add the following subclauses:
4.7.4 Process
Those wishing to check the conformance of their implementation should perform the following checks. First, all
conformance should check the “basic box handling” section of the tests, as this is common to all
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ISO/IEC 14496-4:2004/Amd.24:2008(E)
specifications. Then, the mandatory features of the selected specification should be checked, and finally, of
course, those optional features that the implementation being checked also covers.
The suite of conformance tests do not currently cover deliberately errored files. However, such files do occur
in practice and implementations should be written to be resilient.
There is no tool provided to check the conformance of files. However, such tools do exist; the reference
software can be used to open files in ‘debug’ mode and provide a listing of what it finds, and other trade
associations and standards bodies may have validation tools tailored to their areas.
4.7.5 Areas tested
The attached Excel document has two spreadsheets. The first briefly lists the areas and features covered, and
then has a column for each proposed file. The second sheet provides a br
...